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Sample records for neurod1 specifies neuronal

  1. NeuroD1: developmental expression and regulated genes in the rodent pineal gland

    DEFF Research Database (Denmark)

    Muñoz, Estela M; Bailey, Michael J; Rath, Martin F

    2007-01-01

    NeuroD1/BETA2, a member of the bHLH transcription factor family, is known to influence the fate of specific neuronal, endocrine and retinal cells. We report here that NeuroD1 mRNA is highly abundant in the developing and adult rat pineal gland. Pineal expression begins in the 17-day embryo at which...... time it is also detectable in other brain regions. Expression in the pineal gland increases during the embryonic period and is maintained thereafter at levels equivalent to those found in the cerebellum and retina. In contrast, NeuroD1 mRNA decreases markedly in non-cerebellar brain regions during...... development. Pineal NeuroD1 levels are similar during the day and night, and do not appear to be influenced by sympathetic neural input. Gene expression analysis of the pineal glands from neonatal NeuroD1 knockout mice identifies 127 transcripts that are down-regulated (>twofold, p

  2. Synergistic nuclear import of NeuroD1 and its partner transcription factor, E47, via heterodimerization

    International Nuclear Information System (INIS)

    Mehmood, Rashid; Yasuhara, Noriko; Oe, Souichi; Nagai, Masahiro; Yoneda, Yoshihiro

    2009-01-01

    The transition from undifferentiated pluripotent cells to terminally differentiated neurons is coordinated by a repertoire of transcription factors. NeuroD1 is a type II basic helix loop helix (bHLH) transcription factor that plays critical roles in neuronal differentiation and maintenance in the central nervous system. Its dimerization with E47, a type I bHLH transcription factor, leads to the transcriptional regulation of target genes. Mounting evidence suggests that regulating the localization of transcription factors contributes to the regulation of their activity during development as defects in their localization underlie a variety of developmental disorders. In this study, we attempted to understand the nuclear import mannerisms of NeuroD1 and E47. We found that the nuclear import of NeuroD1 and E47 is energy-dependent and involves the Ran-mediated pathway. Herein, we demonstrate that NeuroD1 and E47 can dimerize inside the cytoplasm before their nuclear import. Moreover, this dimerization promotes nuclear import as the nuclear accumulation of NeuroD1 was enhanced in the presence of E47 in an in vitro nuclear import assay, and NLS-deficient NeuroD1 was successfully imported into the nucleus upon E47 overexpression. NeuroD1 also had a similar effect on the nuclear accumulation of NLS-deficient E47. These findings suggest a novel role for dimerization that may promote, at least partially, the nuclear import of transcription factors allowing them to function efficiently in the nucleus.

  3. NeuroD2 regulates the development of hippocampal mossy fiber synapses

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    Wilke Scott A

    2012-02-01

    Full Text Available Abstract Background The assembly of neural circuits requires the concerted action of both genetically determined and activity-dependent mechanisms. Calcium-regulated transcription may link these processes, but the influence of specific transcription factors on the differentiation of synapse-specific properties is poorly understood. Here we characterize the influence of NeuroD2, a calcium-dependent transcription factor, in regulating the structural and functional maturation of the hippocampal mossy fiber (MF synapse. Results Using NeuroD2 null mice and in vivo lentivirus-mediated gene knockdown, we demonstrate a critical role for NeuroD2 in the formation of CA3 dendritic spines receiving MF inputs. We also use electrophysiological recordings from CA3 neurons while stimulating MF axons to show that NeuroD2 regulates the differentiation of functional properties at the MF synapse. Finally, we find that NeuroD2 regulates PSD95 expression in hippocampal neurons and that PSD95 loss of function in vivo reproduces CA3 neuron spine defects observed in NeuroD2 null mice. Conclusion These experiments identify NeuroD2 as a key transcription factor that regulates the structural and functional differentiation of MF synapses in vivo.

  4. The neurogenic factor NeuroD1 is expressed in post-mitotic cells during juvenile and adult Xenopus neurogenesis and not in progenitor or radial glial cells.

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    Laure Anne D'Amico

    Full Text Available In contrast to mammals that have limited proliferation and neurogenesis capacities, the Xenopus frog exhibit a great potential regarding proliferation and production of new cells in the adult brain. This ability makes Xenopus a useful model for understanding the molecular programs required for adult neurogenesis. Transcriptional factors that control adult neurogenesis in vertebrate species undergoing widespread neurogenesis are unknown. NeuroD1 is a member of the family of proneural genes, which function during embryonic neurogenesis as a potent neuronal differentiation factor. Here, we study in detail the expression of NeuroD1 gene in the juvenile and adult Xenopus brains by in situ hybridization combined with immunodetections for proliferation markers (PCNA, BrdU or in situ hybridizations for cell type markers (Vimentin, Sox2. We found NeuroD1 gene activity in many brain regions, including olfactory bulbs, pallial regions of cerebral hemispheres, preoptic area, habenula, hypothalamus, cerebellum and medulla oblongata. We also demonstrated by double staining NeuroD1/BrdU experiments, after long post-BrdU administration survival times, that NeuroD1 gene activity was turned on in new born neurons during post-metamorphic neurogenesis. Importantly, we provided evidence that NeuroD1-expressing cells at this brain developmental stage were post-mitotic (PCNA- cells and not radial glial (Vimentin+ or progenitors (Sox2+ cells.

  5. Role of NeuroD1 on the negative regulation of Pomc expression by glucocorticoid.

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    Rehana Parvin

    Full Text Available The mechanism of the negative regulation of proopiomelanocortin gene (Pomc by glucocorticoids (Gcs is still unclear in many points. Here, we demonstrated the involvement of neurogenic differentiation factor 1 (NeuroD1 in the Gc-mediated negative regulation of Pomc. Murine pituitary adrenocorticotropic hormone (ACTH producing corticotroph tumor-derived AtT20 cells were treated with dexamethasone (DEX (1-100 nM and cultured for 24 hrs. Thereafter, Pomc mRNA expression was studied by quantitative real-time PCR and rat Pomc promoter (-703/+58 activity was examined by luciferase assay. Both Pomc mRNA expression and Pomc promoter activity were inhibited by DEX in a dose-dependent manner. Deletion and point mutant analyses of Pomc promoter suggested that the DEX-mediated transcriptional repression was mediated via E-box that exists at -376/-371 in the promoter. Since NeuroD1 is known to bind to and activate E-box of the Pomc promoter, we next examined the effect of DEX on NeuroD1 expression. Interestingly, DEX dose-dependently inhibited NeuroD1 mRNA expression, mouse NeuroD1 promoter (-2.2-kb activity, and NeuroD1 protein expression in AtT20 cells. In addition, we confirmed the inhibitory effect of DEX on the interaction of NeuroD1 and E-box on Pomc promoter by chromatin immunoprecipitation (ChIP assay. Finally, overexpression of mouse NeuroD1 could rescue the DEX-mediated inhibition of Pomc mRNA expression and Pomc promoter activity. Taken together, it is suggested that the suppression of NeuroD1 expression and the inhibition of NeuroD1/E-box interaction may play an important role in the Gc-mediated negative regulation of Pomc.

  6. The dosage of the neuroD2 transcription factor regulates amygdala development and emotional learning

    OpenAIRE

    Lin, Chin-Hsing; Hansen, Stacey; Wang, Zhenshan; Storm, Daniel R.; Tapscott, Stephen J.; Olson, James M.

    2005-01-01

    The amygdala is centrally involved in formation of emotional memory and response to fear or risk. We have demonstrated that the lateral and basolateral amygdala nuclei fail to form in neuroD2 null mice and neuroD2 heterozygotes have fewer neurons in this region. NeuroD2 heterozygous mice show profound deficits in emotional learning as assessed by fear conditioning. Unconditioned fear was also diminished in neuroD2 heterozygotes compared to wild-type controls. Several key molecular regulators ...

  7. Conditional induction of Math1 specifies embryonic stem cells to cerebellar granule neuron lineage and promotes differentiation into mature granule neurons.

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    Srivastava, Rupali; Kumar, Manoj; Peineau, Stéphane; Csaba, Zsolt; Mani, Shyamala; Gressens, Pierre; El Ghouzzi, Vincent

    2013-04-01

    Directing differentiation of embryonic stem cells (ESCs) to specific neuronal subtype is critical for modeling disease pathology in vitro. An attractive means of action would be to combine regulatory differentiation factors and extrinsic inductive signals added to the culture medium. In this study, we have generated mature cerebellar granule neurons by combining a temporally controlled transient expression of Math1, a master gene in granule neuron differentiation, with inductive extrinsic factors involved in cerebellar development. Using a Tetracyclin-On transactivation system, we overexpressed Math1 at various stages of ESCs differentiation and found that the yield of progenitors was considerably increased when Math1 was induced during embryonic body stage. Math1 triggered expression of Mbh1 and Mbh2, two target genes directly involved in granule neuron precursor formation and strong expression of early cerebellar territory markers En1 and NeuroD1. Three weeks after induction, we observed a decrease in the number of glial cells and an increase in that of neurons albeit still immature. Combining Math1 induction with extrinsic factors specifically increased the number of neurons that expressed Pde1c, Zic1, and GABAα6R characteristic of mature granule neurons, formed "T-shaped" axons typical of granule neurons, and generated synaptic contacts and action potentials in vitro. Finally, in vivo implantation of Math1-induced progenitors into young adult mice resulted in cell migration and settling of newly generated neurons in the cerebellum. These results show that conditional induction of Math1 drives ESCs toward the cerebellar fate and indicate that acting on both intrinsic and extrinsic factors is a powerful means to modulate ESCs differentiation and maturation into a specific neuronal lineage. Copyright © 2012 AlphaMed Press.

  8. Effect of NeuroD gene silencing on the migration and invasion of human pancreatic cancer cells PANC-1.

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    Wang, Yang; Su, Dong Wei; Gao, Li; Ding, Gui Ling; Ni, Can Rong; Zhu, Ming Hua

    2014-07-01

    The aim of this study is to investigate the influence of Lenti-EGFP-NeuroD-miR, RNAi lentiviral expression vector, on the expression level of NeuroD and migration, and invasion of PANC-1 cell line. PANC-1 cells were cultured and cotransfected with Lenti-EGFP-NeuroD-miR and Lenti-GFP. The infection rate of lentivirus was determined by fluorescence. The interfering effection by the expression of NeuroD mRNA in PANC-1 cells was analyzed by real-time PCR after transfected. Biological behavior of PANC-1 cells transinfected was observed, and the migration and invasion were studied by transwell assay. Intrapancreatic allografts model in nude mice was established to observe the effects of NeuroD on tumorigenesis, tumor growth, and invasion in vivo. The expression of NeuroD mRNA decreased significantly after RNAi lentivirus transinfecting PANC-1 cell. The cell's migration and invasion ability decreased obviously as soon as down regulate of NeuroD in PANC-1 cells. Comparing with control group, the tumors were smaller in size and the invasiveness was inhibited after 8 weeks intrapancreatic allografts in nude mice. Lenti-EGFP-NeuroD-miR transfected into PANC-1 cells shows a stable, effective, and especial blocking expression of NeuroD in mRNA level. The RNAi of lentiviral vector target NeuroD can reduce the migration and invasion abilities of PANC-1 cells.

  9. NEUROD2 and NEUROD3 genes map to human chromosomes 17q12 and 5q23-q31 and mouse chromosomes 11 and 13, respectively

    Energy Technology Data Exchange (ETDEWEB)

    Tamimi, R.M.; Montgomery-Dyer, K.; Tapscott, S.J. [Fred Hutchinson Cancer Research Center, Seattle, WA (United States)] [and others

    1997-03-01

    NEUROD2 and NEUROD3 are transcription factors involved in neurogenesis that are related to the basic helix-loop-helix protein NEUROD. NEUROD2 maps to human chromosome 17q12 and mouse chromosome 11. NEUROD3 maps to human chromosome 5q23-q31 and mouse chromosome 13. 16 refs., 2 figs.

  10. CLINICAL AND MORPHOLOGICAL RESEARCH INTO THE ROLE OF THE TRANSCRIPTION FACTOR NEUROD1 IN VARIOUS TYPES OF PITUITARY ADENOMAS

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    O. M. Raspopova

    2017-01-01

    Full Text Available The role of transcription factors in the pathogenesis of pituitary adenomas is extremely controversial.The aim of the study was to investigate the role of the transcription factor Neuro D1 in various types of pituitary adenomas.Materials and methods. A comparative clinico-morphological study was carried out with immunohistochemical analysis and confocal microscopy of the expression of the transcription factor NeuroD1, six adenohypophysis hormones and Ki-67 in 40 pituitary adenomas and 9 normal pituitary glands.Results. NeuroD1 was expressed in all cases and types of adenomas. The expression level of the transcription factor in adenomas was significantly different from that in the normal pituitary gland (p = 0.006. The average number of cells with expression of NeuroD1 in all tumors was higher than in the normal pituitary gland.Conclusion. NeuroD1 plays one of the key roles in the pathogenesis of pituitary adenomas, regardless of their hormonal status.

  11. NeuroD modulates opioid agonist-selective regulation of adult neurogenesis and contextual memory extinction.

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    Zheng, Hui; Zhang, Yue; Li, Wen; Loh, Horace H; Law, Ping-Yee

    2013-04-01

    Addictive drugs, including opioids, modulate adult neurogenesis. In order to delineate the probable implications of neurogenesis on contextual memory associated with addiction, we investigated opioid agonist-selective regulation of neurogenic differentiation 1 (NeuroD) activities under the conditioned place preference (CPP) paradigm. Training mice with equivalent doses of morphine and fentanyl produced different CPP extinction rates without measurable differences in the CPP acquisition rate or magnitude. Fentanyl-induced CPP required much longer time for extinction than morphine-induced CPP. We observed a parallel decrease in NeuroD activities and neurogenesis after morphine-induced CPP, but not after fentanyl-induced CPP. Increasing NeuroD activities with NeuroD-lentivirus (nd-vir) injection at the dentate gyrus before CPP training reversed morphine-induced decreases in NeuroD activities and neurogenesis, and prolonged the time required for extinction of morphine-induced CPP. On the other hand, decreasing NeuroD activities via injection of miRNA-190-virus (190-vir) reversed the fentanyl effect on NeuroD and neurogenesis and shortened the time required for extinction of fentanyl-induced CPP. Another contextual memory task, the Morris Water Maze (MWM), was affected similarly by alteration of NeuroD activities. The reduction in NeuroD activities either by morphine treatment or 190-vir injection decreased MWM task retention, while the increase in NeuroD activities by nd-vir prolonged MWM task retention. Thus, by controlling NeuroD activities, opioid agonists differentially regulate adult neurogenesis and subsequent contextual memory retention. Such drug-related memory regulation could have implications in eventual context-associated relapse.

  12. Autosomal inheritance of diabetes in two families characterized by obesity and a novel H241Q mutation in NEUROD1

    DEFF Research Database (Denmark)

    Gonsorcíková, Lucie; Pruhová, Stepánka; Cinek, Ondrej

    2008-01-01

    BACKGROUND: The aim of the study was to search for mutations in the NEUROD1 and IPF-1 genes in patients with clinical characteristics of maturity-onset diabetes of the young (MODY) but with no mutations in the HNF-4A (MODY1), GCK (MODY2) and TCF1 (MODY3) genes. METHODS: We studied 30 unrelated...... Czech probands with a clinical diagnosis of MODY (median age at testing, 18 yr; median age at the recognition of hyperglycaemia, 16 yr). The promoter, exons and exon/intron boundaries of the NEUROD1 and IPF-1 genes were examined by polymerase chain reaction-denaturing high performance liquid...... chromatography and direct sequencing. RESULTS: While no mutations were found in the IPF-1 gene, a novel H241Q substitution of NEUROD1 gene was identified in two unrelated families. In the first proband, the H241Q mutation led to early diagnosed (20 yr) hyperglycaemia followed by development of diabetic...

  13. Derivation of human differential photoreceptor-like cells from the iris by defined combinations of CRX, RX and NEUROD.

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    Yuko Seko

    Full Text Available Examples of direct differentiation by defined transcription factors have been provided for beta-cells, cardiomyocytes and neurons. In the human visual system, there are four kinds of photoreceptors in the retina. Neural retina and iris-pigmented epithelium (IPE share a common developmental origin, leading us to test whether human iris cells could differentiate to retinal neurons. We here define the transcription factor combinations that can determine human photoreceptor cell fate. Expression of rhodopsin, blue opsin and green/red opsin in induced photoreceptor cells were dependent on combinations of transcription factors: A combination of CRX and NEUROD induced rhodopsin and blue opsin, but did not induce green opsin; a combination of CRX and RX induced blue opsin and green/red opsin, but did not induce rhodopsin. Phototransduction-related genes as well as opsin genes were up-regulated in those cells. Functional analysis; i.e. patch clamp recordings, clearly revealed that generated photoreceptor cells, induced by CRX, RX and NEUROD, responded to light. The response was an inward current instead of the typical outward current. These data suggest that photosensitive photoreceptor cells can be generated by combinations of transcription factors. The combination of CRX and RX generate immature photoreceptors: and additional NEUROD promotes maturation. These findings contribute substantially to a major advance toward eventual cell-based therapy for retinal degenerative diseases.

  14. 5′UTR of the Neurogenic bHLH Nex1/MATH-2/NeuroD6 Gene Is Regulated by Two Distinct Promoters Through CRE and C/EBP Binding Sites

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    Uittenbogaard, Martine; Martinka, Debra L.; Johnson, Peter F.; Vinson, Charles; Chiaramello, Anne

    2009-01-01

    Expression of the bHLH transcription factor Nex1/MATH-2/NeuroD6, a member of the NeuroD subfamily, parallels overt neuronal differentiation and synaptogenesis during brain development. Our previous studies have shown that Nex1 is a critical effector of the NGF pathway and promotes neuronal differentiation and survival of PC12 cells in the absence of growth factors. In this study, we investigated the transcriptional regulation of the Nex1 gene during NGF-induced neuronal differentiation. We found that Nex1 expression is under the control of two conserved promoters, Nex1-P1 and Nex1-P2, located in two distinct non-coding exons. Both promoters are TATA-less with multiple transcription start sites, and are activated on NGF or cAMP exposure. Luciferase-reporter assays showed that the Nex1-P2 promoter activity is stronger than the Nex1-P1 promoter activity, which supports the previously reported differential expression levels of Nex1 transcripts throughout brain development. Using a combination of DNaseI footprinting, EMSA assays, and site-directed mutagenesis, we identified the essential regulatory elements within the first 2 kb of the Nex1 5′UTR. The Nex1-P1 promoter is mainly regulated by a conserved CRE element, whereas the Nex1-P2 promoter is under the control of a conserved C/EBP binding site. Overexpression of wild-type C/EBPβ resulted in increased Nex1-P2 promoter activity in NGF-differentiated PC12 cells. The fact that Nex1 is a target gene of C/EBPβ provides new insight into the C/EBP transcriptional cascade known to promote neurogenesis, while repressing gliogenesis. PMID:17075921

  15. Omega-3 Polyunsaturated Fatty Acids Enhance Neuronal Differentiation in Cultured Rat Neural Stem Cells

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    Masanori Katakura

    2013-01-01

    Full Text Available Polyunsaturated fatty acids (PUFAs can induce neurogenesis and recovery from brain diseases. However, the exact mechanisms of the beneficial effects of PUFAs have not been conclusively described. We recently reported that docosahexaenoic acid (DHA induced neuronal differentiation by decreasing Hes1 expression and increasing p27kip1 expression, which causes cell cycle arrest in neural stem cells (NSCs. In the present study, we examined the effect of eicosapentaenoic acid (EPA and arachidonic acid (AA on differentiation, expression of basic helix-loop-helix transcription factors (Hes1, Hes6, and NeuroD, and the cell cycle of cultured NSCs. EPA also increased mRNA levels of Hes1, an inhibitor of neuronal differentiation, Hes6, an inhibitor of Hes1, NeuroD, and Map2 mRNA and Tuj-1-positive cells (a neuronal marker, indicating that EPA induced neuronal differentiation. EPA increased the mRNA levels of p21cip1 and p27kip1, a cyclin-dependent kinase inhibitor, which indicated that EPA induced cell cycle arrest. Treatment with AA decreased Hes1 mRNA but did not affect NeuroD and Map2 mRNA levels. Furthermore, AA did not affect the number of Tuj-1-positive cells or cell cycle progression. These results indicated that EPA could be involved in neuronal differentiation by mechanisms alternative to those of DHA, whereas AA did not affect neuronal differentiation in NSCs.

  16. Direct Reprogramming of Spiral Ganglion Non-neuronal Cells into Neurons: Toward Ameliorating Sensorineural Hearing Loss by Gene Therapy

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    Teppei Noda

    2018-02-01

    Full Text Available Primary auditory neurons (PANs play a critical role in hearing by transmitting sound information from the inner ear to the brain. Their progressive degeneration is associated with excessive noise, disease and aging. The loss of PANs leads to permanent hearing impairment since they are incapable of regenerating. Spiral ganglion non-neuronal cells (SGNNCs, comprised mainly of glia, are resident within the modiolus and continue to survive after PAN loss. These attributes make SGNNCs an excellent target for replacing damaged PANs through cellular reprogramming. We used the neurogenic pioneer transcription factor Ascl1 and the auditory neuron differentiation factor NeuroD1 to reprogram SGNNCs into induced neurons (iNs. The overexpression of both Ascl1 and NeuroD1 in vitro generated iNs at high efficiency. Transcriptome analyses revealed that iNs displayed a transcriptome profile resembling that of endogenous PANs, including expression of several key markers of neuronal identity: Tubb3, Map2, Prph, Snap25, and Prox1. Pathway analyses indicated that essential pathways in neuronal growth and maturation were activated in cells upon neuronal induction. Furthermore, iNs extended projections toward cochlear hair cells and cochlear nucleus neurons when cultured with each respective tissue. Taken together, our study demonstrates that PAN-like neurons can be generated from endogenous SGNNCs. This work suggests that gene therapy can be a viable strategy to treat sensorineural hearing loss caused by degeneration of PANs.

  17. Wnt3a upregulates brain-derived insulin by increasing NeuroD1 via Wnt/β-catenin signaling in the hypothalamus.

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    Lee, Jaemeun; Kim, Kyungchan; Yu, Seong-Woon; Kim, Eun-Kyoung

    2016-03-08

    Insulin plays diverse roles in the brain. Although insulin produced by pancreatic β-cells that crosses the blood-brain barrier is a major source of brain insulin, recent studies suggest that insulin is also produced locally within the brain. However, the mechanisms underlying the production of brain-derived insulin (BDI) are not yet known. Here, we examined the effect of Wnt3a on BDI production in a hypothalamic cell line and hypothalamic tissue. In N39 hypothalamic cells, Wnt3a treatment significantly increased the expression of the Ins2 gene, which encodes the insulin isoform predominant in the mouse brain, by activating Wnt/β-catenin signaling. The concentration of insulin was higher in culture medium of Wnt3a-treated cells than in that of untreated cells. Interestingly, neurogenic differentiation 1 (NeuroD1), a target of Wnt/β-catenin signaling and one of transcription factors for insulin, was also induced by Wnt3a treatment in a time- and dose-dependent manner. In addition, the treatment of BIO, a GSK3 inhibitor, also increased the expression of Ins2 and NeuroD1. Knockdown of NeuroD1 by lentiviral shRNAs reduced the basal expression of Ins2 and suppressed Wnt3a-induced Ins2 expression. To confirm the Wnt3a-induced increase in Ins2 expression in vivo, Wnt3a was injected into the hypothalamus of mice. Wnt3a increased the expression of NeuroD1 and Ins2 in the hypothalamus in a manner similar to that observed in vitro. Taken together, these results suggest that BDI production is regulated by the Wnt/β-catenin/NeuroD1 pathway in the hypothalamus. Our findings will help to unravel the regulation of BDI production in the hypothalamus.

  18. Extremely Low-Frequency Electromagnetic Fields Promote In Vitro Neuronal Differentiation and Neurite Outgrowth of Embryonic Neural Stem Cells via Up-Regulating TRPC1

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    Ma, Qinlong; Chen, Chunhai; Deng, Ping; Zhu, Gang; Lin, Min; Zhang, Lei; Xu, Shangcheng; He, Mindi; Lu, Yonghui; Duan, Weixia; Pi, Huifeng; Cao, Zhengwang; Pei, Liping; Li, Min; Liu, Chuan; Zhang, Yanwen; Zhong, Min; Zhou, Zhou; Yu, Zhengping

    2016-01-01

    Exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) can enhance hippocampal neurogenesis in adult mice. However, little is focused on the effects of ELF-EMFs on embryonic neurogenesis. Here, we studied the potential effects of ELF-EMFs on embryonic neural stem cells (eNSCs). We exposed eNSCs to ELF-EMF (50 Hz, 1 mT) for 1, 2, and 3 days with 4 hours per day. We found that eNSC proliferation and maintenance were significantly enhanced after ELF-EMF exposure in proliferation medium. ELF-EMF exposure increased the ratio of differentiated neurons and promoted the neurite outgrowth of eNSC-derived neurons without influencing astrocyes differentiation and the cell apoptosis. In addition, the expression of the proneural genes, NeuroD and Ngn1, which are crucial for neuronal differentiation and neurite outgrowth, was increased after ELF-EMF exposure. Moreover, the expression of transient receptor potential canonical 1 (TRPC1) was significantly up-regulated accompanied by increased the peak amplitude of intracellular calcium level induced by ELF-EMF. Furthermore, silencing TRPC1 expression eliminated the up-regulation of the proneural genes and the promotion of neuronal differentiation and neurite outgrowth induced by ELF-EMF. These results suggest that ELF-EMF exposure promotes the neuronal differentiation and neurite outgrowth of eNSCs via up-regulation the expression of TRPC1 and proneural genes (NeuroD and Ngn1). These findings also provide new insights in understanding the effects of ELF-EMF exposure on embryonic brain development. PMID:26950212

  19. Multiple zebrafish atoh1 genes specify a diversity of neuronal types in the zebrafish cerebellum.

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    Kidwell, Chelsea U; Su, Chen-Ying; Hibi, Masahiko; Moens, Cecilia B

    2018-06-01

    A single Atoh1 basic-helix-loop-helix transcription factor specifies multiple neuron types in the mammalian cerebellum and anterior hindbrain. The zebrafish genome encodes three paralagous atoh1 genes whose functions in cerebellum and anterior hindbrain development we explore here. With use of a transgenic reporter, we report that zebrafish atoh1c-expressing cells are organized in two distinct domains that are separated both by space and developmental time. An early isthmic expression domain gives rise to an extracerebellar population in rhombomere 1 and an upper rhombic lip domain gives rise to granule cell progenitors that migrate to populate all four granule cell territories of the fish cerebellum. Using genetic mutants we find that of the three zebrafish atoh1 paralogs, atoh1c and atoh1a are required for the full complement of granule neurons. Surprisingly, the two genes are expressed in non-overlapping granule cell progenitor populations, indicating that fish use duplicate atoh1 genes to generate granule cell diversity that is not detected in mammals. Finally, live imaging of granule cell migration in wildtype and atoh1c mutant embryos reveals that while atoh1c is not required for granule cell specification per se, it is required for granule cells to delaminate and migrate away from the rhombic lip. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Small Molecules Modulate Chromatin Accessibility to Promote NEUROG2-Mediated Fibroblast-to-Neuron Reprogramming

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    Derek K. Smith

    2016-11-01

    Full Text Available Pro-neural transcription factors and small molecules can induce the reprogramming of fibroblasts into functional neurons; however, the immediate-early molecular events that catalyze this conversion have not been well defined. We previously demonstrated that neurogenin 2 (NEUROG2, forskolin (F, and dorsomorphin (D can reprogram fibroblasts into functional neurons with high efficiency. Here, we used this model to define the genetic and epigenetic events that initiate an acquisition of neuronal identity. We demonstrate that NEUROG2 is a pioneer factor, FD enhances chromatin accessibility and H3K27 acetylation, and synergistic transcription activated by these factors is essential to successful reprogramming. CREB1 promotes neuron survival and acts with NEUROG2 to upregulate SOX4, which co-activates NEUROD1 and NEUROD4. In addition, SOX4 targets SWI/SNF subunits and SOX4 knockdown results in extensive loss of open chromatin and abolishes reprogramming. Applying these insights, adult human glioblastoma cell and skin fibroblast reprogramming can be improved using SOX4 or chromatin-modifying chemicals.

  1. A BMP-mediated transcriptional cascade involving Cash1 and Tlx-3 specifies first-order relay sensory neurons in the developing hindbrain.

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    Hornbruch, Amata; Ma, Grace; Ballermann, Mark A; Tumova, Katerina; Liu, Dan; Cairine Logan, C

    2005-07-01

    The divergent homeobox-containing transcription factor, Tlx-3 (also known as Hox11L2/Rnx), is required for proper formation of first-order relay sensory neurons in the developing vertebrate brainstem. To date, however, the inductive signals and transcriptional regulatory cascade underlying their development are poorly understood. We previously isolated the chick Tlx-3 homologue and showed it is expressed early (i.e. beginning at HH15) in distinct subcomponents of both the trigeminal/solitary and vestibular nuclei. Here we show via in vivo rhombomere inversions that expression of Tlx-3 is under control of local environmental signals. Our RNA in situ analysis shows expression of the BMP-specific receptor, Bmpr-1b, correlates well with Tlx-3. Furthermore, manipulation of the BMP signaling pathway in vivo via electroporation of expression vectors encoding either BMP or NOGGIN coupled with MASH1 gain-of-function experiments demonstrate that a BMP-mediated transcriptional cascade involving Cash1 and Tlx-3 specifies first-order relay sensory neurons in the developing brainstem. Notably, high-level Noggin misexpression results in an increase in newly differentiated Tlx-3+ neurons that correlates with a corresponding increase in the number of Calretinin+ neurons in vestibular nuclei at later developmental stages strongly suggesting that Tlx-3, in addition to being required for proper formation of somatic as well as visceral sensory neurons in the trigeminal and solitary nuclei, respectively, is sufficient for proper formation of special somatic sensory neurons in vestibular nuclei.

  2. Terminal Differentiation of Adult Hippocampal Progenitor Cells Is a Step Functionally Dissociable from Proliferation and Is Controlled by Tis21, Id3 and NeuroD2

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    Laura Micheli

    2017-07-01

    Full Text Available Cell proliferation and differentiation are interdependent processes. Here, we have asked to what extent the two processes of neural progenitor cell amplification and differentiation are functionally separated. Thus, we analyzed whether it is possible to rescue a defect of terminal differentiation in progenitor cells of the dentate gyrus, where new neurons are generated throughout life, by inducing their proliferation and/or their differentiation with different stimuli appropriately timed. As a model we used the Tis21 knockout mouse, whose dentate gyrus neurons, as demonstrated by us and others, have an intrinsic defect of terminal differentiation. We first tested the effect of two proliferative as well as differentiative neurogenic stimuli, one pharmacological (fluoxetine, the other cognitive (the Morris water maze (MWM training. Both effectively enhanced the number of new dentate gyrus neurons produced, and fluoxetine also reduced the S-phase length of Tis21 knockout dentate gyrus progenitor cells and increased the rate of differentiation of control cells, but neither factor enhanced the defective rate of differentiation. In contrast, the defect of terminal differentiation was fully rescued by in vivo infection of proliferating dentate gyrus progenitor cells with retroviruses either silencing Id3, an inhibitor of neural differentiation, or expressing NeuroD2, a proneural gene expressed in terminally differentiated dentate gyrus neurons. This is the first demonstration that NeuroD2 or the silencing of Id3 can activate the differentiation of dentate gyrus neurons, complementing a defect of differentiation. It also highlights how the rate of differentiation of dentate gyrus neurons is regulated genetically at several levels and that a neurogenic stimulus for amplification of neural stem/progenitor cells may not be sufficient in itself to modify this rate.

  3. Associations of NEUROD2 polymorphisms and change of cognitive dysfunctions in schizophrenia and schizoaffective disorder after eight weeks of antipsychotic treatment.

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    Spellmann, Ilja; Riedel, Michael; Städtler, Julia; Zill, Peter; Obermeier, Michael; Cerovecki, Anja; Dehning, Sandra; Schennach, Rebecca; Epple, Maria; Opgen-Rhein, Markus; Müller, Norbert; Bondy, Brigitta; Möller, Hans-Jürgen; Musil, Richard

    2017-07-01

    NEUROD2 is a neurospecific helix-loop-helix transcription factor which has an impact on the regulation of glutamatergic and GABAergic genes. We investigated an association of NEUROD2 with neurocognitive dysfunctions in schizophrenia and schizoaffective disorder patients before and during treatment with different second-generation antipsychotics. Patients were genotyped for four different polymorphisms of the NEUROD2 gene ((rs9889354(A/G), rs1877032(C/T), rs12453682(C/T) and rs11078918(C/G)). Cognitive function was assessed at baseline and week 8. Results of individual neuropsychological tests were assigned to six cognitive domains (reaction time and quality; executive function; working, verbal and visual memory) and a general cognitive index. 167 patients were included in the study. The NEUROD2 exonic polymorphism rs11078918 showed significant associations with verbal memory and executive functions, whereas the NEUROD2 polymorphism rs12453682 was significantly associated with working and verbal memory, executive functions and with a cognitive index. Significant associations were found at baseline and after eight weeks. Moreover, significant associations between the change in neuropsychological test results during antipsychotic treatment and the NEUROD2 polymorphisms rs11078918 and rs12453682 were observed. Our findings suggest that the NEUROD2 gene could play a role in the pathophysiology of neurocognitive dysfunctions as well as in the change of cognitive symptoms under antipsychotic treatment in schizophrenia and schizoaffective disorder.

  4. The Herfa-Neurode hazardous waste repository in bedded salt as an operating model for safe mixed waste disposal

    International Nuclear Information System (INIS)

    Rempe, N.T.

    1991-01-01

    For 18 years, The Herfa-Neurode underground repository has demonstrated the environmentally sound disposal of hazardous waste in a former potash mine. Its principal characteristics make it an excellent analogue to the Waste Isolation Pilot Plant (WIPP). The Environmental Protection Agency has ruled in its first conditional no-migration determination that is reasonably certain that no hazardous constituents of the mixed waste, destined for the WIPP during its test phase, will migrate from the site for up to ten years. Knowledge of and reference to the Herfa-Neurode operating model may substantially improve the no-migration variance petition for the WIPP's disposal phase and thereby expedite its approval. 2 refs., 1 fig., 1 tab

  5. NeuroD Modulates Opioid Agonist-Selective Regulation of Adult Neurogenesis and Contextual Memory Extinction

    OpenAIRE

    Zheng, Hui; Zhang, Yue; Li, Wen; Loh, Horace H; Law, Ping-Yee

    2013-01-01

    Addictive drugs, including opioids, modulate adult neurogenesis. In order to delineate the probable implications of neurogenesis on contextual memory associated with addiction, we investigated opioid agonist-selective regulation of neurogenic differentiation 1 (NeuroD) activities under the conditioned place preference (CPP) paradigm. Training mice with equivalent doses of morphine and fentanyl produced different CPP extinction rates without measurable differences in the CPP acquisition rate o...

  6. Rosiglitazone stimulates the release and synthesis of insulin by enhancing GLUT-2, glucokinase and BETA2/NeuroD expression

    International Nuclear Information System (INIS)

    Kim, Hyo-Sup; Noh, Jung-Hyun; Hong, Seung-Hyun; Hwang, You-Cheol; Yang, Tae-Young; Lee, Myung-Shik; Kim, Kwang-Won; Lee, Moon-Kyu

    2008-01-01

    Peroxisome proliferator-activated receptor (PPAR)-γ is a member of the nuclear receptor superfamily, and its ligands, the thiazolidinediones, might directly stimulate insulin release and insulin synthesis in pancreatic β-cells. In the present study, we examined the effects of rosiglitazone (RGZ) on insulin release and synthesis in pancreatic β-cell (INS-1). Insulin release and synthesis were stimulated by treatment with RGZ for 24 h. RGZ upregulated the expressions of GLUT-2 and glucokinase (GCK). Moreover, it was found that RGZ increased the expression of BETA2/NeuroD gene which could regulate insulin gene expression. These results suggest that RGZ could stimulate the release and synthesis of insulin through the upregulation of GLUT-2, GCK, and BETA2/NeuroD gene expression

  7. Specification of spatial identities of cerebellar neuron progenitors by ptf1a and atoh1 for proper production of GABAergic and glutamatergic neurons.

    Science.gov (United States)

    Yamada, Mayumi; Seto, Yusuke; Taya, Shinichiro; Owa, Tomoo; Inoue, Yukiko U; Inoue, Takayoshi; Kawaguchi, Yoshiya; Nabeshima, Yo-Ichi; Hoshino, Mikio

    2014-04-02

    In the cerebellum, the bHLH transcription factors Ptf1a and Atoh1 are expressed in distinct neuroepithelial regions, the ventricular zone (VZ) and the rhombic lip (RL), and are required for producing GABAergic and glutamatergic neurons, respectively. However, it is unclear whether Ptf1a or Atoh1 is sufficient for specifying GABAergic or glutamatergic neuronal fates. To test this, we generated two novel knock-in mouse lines, Ptf1a(Atoh1) and Atoh1(Ptf1a), that are designed to express Atoh1 and Ptf1a ectopically in the VZ and RL, respectively. In Ptf1a(Atoh1) embryos, ectopically Atoh1-expressing VZ cells produced glutamatergic neurons, including granule cells and deep cerebellar nuclei neurons. Correspondingly, in Atoh1(Ptf1a) animals, ectopically Ptf1a-expressing RL cells produced GABAergic populations, such as Purkinje cells and GABAergic interneurons. Consistent results were also obtained from in utero electroporation of Ptf1a or Atoh1 into embryonic cerebella, suggesting that Ptf1a and Atoh1 are essential and sufficient for GABAergic versus glutamatergic specification in the neuroepithelium. Furthermore, birthdating analyses with BrdU in the knock-in mice or with electroporation studies showed that ectopically produced fate-changed neuronal types were generated at temporal schedules closely simulating those of the wild-type RL and VZ, suggesting that the VZ and RL share common temporal information. Observations of knock-in brains as well as electroporated brains revealed that Ptf1a and Atoh1 mutually negatively regulate their expression, probably contributing to formation of non-overlapping neuroepithelial domains. These findings suggest that Ptf1a and Atoh1 specify spatial identities of cerebellar neuron progenitors in the neuroepithelium, leading to appropriate production of GABAergic and glutamatergic neurons, respectively.

  8. EGL-13/SoxD specifies distinct O2 and CO2 sensory neuron fates in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Jakob Gramstrup Petersen

    2013-05-01

    Full Text Available Animals harbor specialized neuronal systems that are used for sensing and coordinating responses to changes in oxygen (O2 and carbon dioxide (CO2. In Caenorhabditis elegans, the O2/CO2 sensory system comprises functionally and morphologically distinct sensory neurons that mediate rapid behavioral responses to exquisite changes in O2 or CO2 levels via different sensory receptors. How the diversification of the O2- and CO2-sensing neurons is established is poorly understood. We show here that the molecular identity of both the BAG (O2/CO2-sensing and the URX (O2-sensing neurons is controlled by the phylogenetically conserved SoxD transcription factor homolog EGL-13. egl-13 mutant animals fail to fully express the distinct terminal gene batteries of the BAG and URX neurons and, as such, are unable to mount behavioral responses to changes in O2 and CO2. We found that the expression of egl-13 is regulated in the BAG and URX neurons by two conserved transcription factors-ETS-5(Ets factor in the BAG neurons and AHR-1(bHLH factor in the URX neurons. In addition, we found that EGL-13 acts in partially parallel pathways with both ETS-5 and AHR-1 to direct BAG and URX neuronal fate respectively. Finally, we found that EGL-13 is sufficient to induce O2- and CO2-sensing cell fates in some cellular contexts. Thus, the same core regulatory factor, egl-13, is required and sufficient to specify the distinct fates of O2- and CO2-sensing neurons in C. elegans. These findings extend our understanding of mechanisms of neuronal diversification and the regulation of molecular factors that may be conserved in higher organisms.

  9. EGL-13/SoxD Specifies Distinct O2 and CO2 Sensory Neuron Fates in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Gramstrup Petersen, Jakob; Rojo Romanos, Teresa; Juozaityte, Vaida

    2013-01-01

    that EGL-13 is sufficient to induce O2- and CO2-sensing cell fates in some cellular contexts. Thus, the same core regulatory factor, egl-13, is required and sufficient to specify the distinct fates of O2- and CO2-sensing neurons in C. elegans. These findings extend our understanding of mechanisms......Animals harbor specialized neuronal systems that are used for sensing and coordinating responses to changes in oxygen (O2) and carbon dioxide (CO2). In Caenorhabditis elegans, the O2/CO2 sensory system comprises functionally and morphologically distinct sensory neurons that mediate rapid behavioral...

  10. Separate transcriptionally regulated pathways specify distinct classes of sister dendrites in a nociceptive neuron.

    Science.gov (United States)

    O'Brien, Barbara M J; Palumbos, Sierra D; Novakovic, Michaela; Shang, Xueying; Sundararajan, Lakshmi; Miller, David M

    2017-12-15

    The dendritic processes of nociceptive neurons transduce external signals into neurochemical cues that alert the organism to potentially damaging stimuli. The receptive field for each sensory neuron is defined by its dendritic arbor, but the mechanisms that shape dendritic architecture are incompletely understood. Using the model nociceptor, the PVD neuron in C. elegans, we determined that two types of PVD lateral branches project along the dorsal/ventral axis to generate the PVD dendritic arbor: (1) Pioneer dendrites that adhere to the epidermis, and (2) Commissural dendrites that fasciculate with circumferential motor neuron processes. Previous reports have shown that the LIM homeodomain transcription factor MEC-3 is required for all higher order PVD branching and that one of its targets, the claudin-like membrane protein HPO-30, preferentially promotes outgrowth of pioneer branches. Here, we show that another MEC-3 target, the conserved TFIIA-like zinc finger transcription factor EGL-46, adopts the alternative role of specifying commissural dendrites. The known EGL-46 binding partner, the TEAD transcription factor EGL-44, is also required for PVD commissural branch outgrowth. Double mutants of hpo-30 and egl-44 show strong enhancement of the lateral branching defect with decreased numbers of both pioneer and commissural dendrites. Thus, HPO-30/Claudin and EGL-46/EGL-44 function downstream of MEC-3 and in parallel acting pathways to direct outgrowth of two distinct classes of PVD dendritic branches. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Generation of induced neurons by direct reprogramming in the mammalian cochlea.

    Science.gov (United States)

    Nishimura, K; Weichert, R M; Liu, W; Davis, R L; Dabdoub, A

    2014-09-05

    Primary auditory neurons (ANs) in the mammalian cochlea play a critical role in hearing as they transmit auditory information in the form of electrical signals from mechanosensory cochlear hair cells in the inner ear to the brainstem. Their progressive degeneration is associated with disease conditions, excessive noise exposure and aging. Replacement of ANs, which lack the ability to regenerate spontaneously, would have a significant impact on research and advancement in cochlear implants in addition to the amelioration of hearing impairment. The aim of this study was to induce a neuronal phenotype in endogenous non-neural cells in the cochlea, which is the essential organ of hearing. Overexpression of a neurogenic basic helix-loop-helix transcription factor, Ascl1, in the cochlear non-sensory epithelial cells induced neurons at high efficiency at embryonic, postnatal and juvenile stages. Moreover, induced neurons showed typical properties of neuron morphology, gene expression and electrophysiology. Our data indicate that Ascl1 alone or Ascl1 and NeuroD1 is sufficient to reprogram cochlear non-sensory epithelial cells into functional neurons. Generation of neurons from non-neural cells in the cochlea is an important step for the regeneration of ANs in the mature mammalian cochlea. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  12. Zebrafish diras1 Promoted Neurite Outgrowth in Neuro-2a Cells and Maintained Trigeminal Ganglion Neurons In Vivo via Rac1-Dependent Pathway.

    Science.gov (United States)

    Yeh, Chi-Wei; Hsu, Li-Sung

    2016-12-01

    The small GTPase Ras superfamily regulates several neuronal functions including neurite outgrowth and neuron proliferation. In this study, zebrafish diras1a and diras1b were identified and were found to be mainly expressed in the central nervous system and dorsal neuron ganglion. Overexpression of green fluorescent protein (GFP)-diras1a or GFP-diras1b triggered neurite outgrowth of Neuro-2a cells. The wild types, but not the C terminus truncated forms, of diras1a and diras1b elevated the protein level of Ras-related C3 botulinum toxin substrate 1 (Rac1) and downregulated Ras homologous member A (RhoA) expression. Glutathione S-transferase (GST) pull-down assay also revealed that diras1a and diras1b enhanced Rac1 activity. Interfering with Rac1, Pak1, or cyclin-dependent kinase 5 (CDK5) activity or with the Arp2/3 inhibitor prevented diras1a and diras1b from mediating the neurite outgrowth effects. In the zebrafish model, knockdown of diras1a and/or diras1b by morpholino antisense oligonucleotides not only reduced axon guidance but also caused the loss of trigeminal ganglion without affecting the precursor markers, such as ngn1 and neuroD. Co-injection with messenger RNA (mRNA) derived from mouse diras1 or constitutively active human Rac1 restored the population of trigeminal ganglion. In conclusion, we provided preliminary evidence that diras1 is involved in neurite outgrowth and maintains the number of trigeminal ganglions through the Rac1-dependent pathway.

  13. DNA methylation in the human cerebral cortex is dynamically regulated throughout the life span and involves differentiated neurons.

    Directory of Open Access Journals (Sweden)

    Kimberly D Siegmund

    Full Text Available The role of DNA cytosine methylation, an epigenetic regulator of chromatin structure and function, during normal and pathological brain development and aging remains unclear. Here, we examined by MethyLight PCR the DNA methylation status at 50 loci, encompassing primarily 5' CpG islands of genes related to CNS growth and development, in temporal neocortex of 125 subjects ranging in age from 17 weeks of gestation to 104 years old. Two psychiatric disease cohorts--defined by chronic neurodegeneration (Alzheimer's or lack thereof (schizophrenia--were included. A robust and progressive rise in DNA methylation levels across the lifespan was observed for 8/50 loci (GABRA2, GAD1, HOXA1, NEUROD1, NEUROD2, PGR, STK11, SYK typically in conjunction with declining levels of the corresponding mRNAs. Another 16 loci were defined by a sharp rise in DNA methylation levels within the first few months or years after birth. Disease-associated changes were limited to 2/50 loci in the Alzheimer's cohort, which appeared to reflect an acceleration of the age-related change in normal brain. Additionally, methylation studies on sorted nuclei provided evidence for bidirectional methylation events in cortical neurons during the transition from childhood to advanced age, as reflected by significant increases at 3, and a decrease at 1 of 10 loci. Furthermore, the DNMT3a de novo DNA methyl-transferase was expressed across all ages, including a subset of neurons residing in layers III and V of the mature cortex. Therefore, DNA methylation is dynamically regulated in the human cerebral cortex throughout the lifespan, involves differentiated neurons, and affects a substantial portion of genes predominantly by an age-related increase.

  14. Constitutive Overexpression of the Basic Helix-Loop-Helix Nex1/MATH-2 Transcription Factor Promotes Neuronal Differentiation of PC12 Cells and Neurite Regeneration

    Science.gov (United States)

    Uittenbogaard, Martine; Chiaramello, Anne

    2009-01-01

    Elucidation of the intricate transcriptional pathways leading to neural differentiation and the establishment of neuronal identity is critical to the understanding and design of therapeutic approaches. Among the important players, the basic helix-loop-helix (bHLH) transcription factors have been found to be pivotal regulators of neurogenesis. In this study, we investigate the role of the bHLH differentiation factor Nex1/MATH-2 in conjunction with the nerve growth factor (NGF) signaling pathway using the rat phenochromocytoma PC12 cell line. We report that the expression of Nex1 protein is induced after 5 hr of NGF treatment and reaches maximal levels at 24 hr, when very few PC12 cells have begun extending neurites and ceased cell division. Furthermore, our study demonstrates that Nex1 has the ability to trigger neuronal differentiation of PC12 cells in the absence of neurotrophic factor. We show that Nex1 plays an important role in neurite outgrowth and has the capacity to regenerate neurite outgrowth in the absence of NGF. These results are corroborated by the fact that Nex1 targets a repertoire of distinct types of genes associated with neuronal differentiation, such as GAP-43, βIII-tubulin, and NeuroD. In addition, our findings show that Nex1 up-regulates the expression of the mitotic inhibitor p21WAF1, thus linking neuronal differentiation to cell cycle withdrawal. Finally, our studies show that overexpression of a Nex1 mutant has the ability to block the execution of NGF-induced differentiation program, suggesting that Nex1 may be an important effector of the NGF signaling pathway. PMID:11782967

  15. Direct Conversion of Equine Adipose-Derived Stem Cells into Induced Neuronal Cells Is Enhanced in Three-Dimensional Culture.

    Science.gov (United States)

    Petersen, Gayle F; Hilbert, Bryan J; Trope, Gareth D; Kalle, Wouter H J; Strappe, Padraig M

    2015-12-01

    The ability to culture neurons from horses may allow further investigation into equine neurological disorders. In this study, we demonstrate the generation of induced neuronal cells from equine adipose-derived stem cells (EADSCs) using a combination of lentiviral vector expression of the neuronal transcription factors Brn2, Ascl1, Myt1l (BAM) and NeuroD1 and a defined chemical induction medium, with βIII-tubulin-positive induced neuronal cells displaying a distinct neuronal morphology of rounded and compact cell bodies, extensive neurite outgrowth, and branching of processes. Furthermore, we investigated the effects of dimensionality on neuronal transdifferentiation, comparing conventional two-dimensional (2D) monolayer culture against three-dimensional (3D) culture on a porous polystyrene scaffold. Neuronal transdifferentiation was enhanced in 3D culture, with evenly distributed cells located on the surface and throughout the scaffold. Transdifferentiation efficiency was increased in 3D culture, with an increase in mean percent conversion of more than 100% compared to 2D culture. Additionally, induced neuronal cells were shown to transit through a Nestin-positive precursor state, with MAP2 and Synapsin 2 expression significantly increased in 3D culture. These findings will help to increase our understanding of equine neuropathogenesis, with prospective roles in disease modeling, drug screening, and cellular replacement for treatment of equine neurological disorders.

  16. Distinct functional and temporal requirements for zebrafish Hdac1 during neural crest-derived craniofacial and peripheral neuron development.

    Directory of Open Access Journals (Sweden)

    Myron S Ignatius

    Full Text Available The regulation of gene expression is accomplished by both genetic and epigenetic means and is required for the precise control of the development of the neural crest. In hdac1(b382 mutants, craniofacial cartilage development is defective in two distinct ways. First, fewer hoxb3a, dlx2 and dlx3-expressing posterior branchial arch precursors are specified and many of those that are consequently undergo apoptosis. Second, in contrast, normal numbers of progenitors are present in the anterior mandibular and hyoid arches, but chondrocyte precursors fail to terminally differentiate. In the peripheral nervous system, there is a disruption of enteric, DRG and sympathetic neuron differentiation in hdac1(b382 mutants compared to wildtype embryos. Specifically, enteric and DRG-precursors differentiate into neurons in the anterior gut and trunk respectively, while enteric and DRG neurons are rarely present in the posterior gut and tail. Sympathetic neuron precursors are specified in hdac1(b382 mutants and they undergo generic neuronal differentiation but fail to undergo noradrenergic differentiation. Using the HDAC inhibitor TSA, we isolated enzyme activity and temporal requirements for HDAC function that reproduce hdac1(b382 defects in craniofacial and sympathetic neuron development. Our study reveals distinct functional and temporal requirements for zebrafish hdac1 during neural crest-derived craniofacial and peripheral neuron development.

  17. Distinct functional and temporal requirements for zebrafish Hdac1 during neural crest-derived craniofacial and peripheral neuron development.

    Science.gov (United States)

    Ignatius, Myron S; Unal Eroglu, Arife; Malireddy, Smitha; Gallagher, Glen; Nambiar, Roopa M; Henion, Paul D

    2013-01-01

    The regulation of gene expression is accomplished by both genetic and epigenetic means and is required for the precise control of the development of the neural crest. In hdac1(b382) mutants, craniofacial cartilage development is defective in two distinct ways. First, fewer hoxb3a, dlx2 and dlx3-expressing posterior branchial arch precursors are specified and many of those that are consequently undergo apoptosis. Second, in contrast, normal numbers of progenitors are present in the anterior mandibular and hyoid arches, but chondrocyte precursors fail to terminally differentiate. In the peripheral nervous system, there is a disruption of enteric, DRG and sympathetic neuron differentiation in hdac1(b382) mutants compared to wildtype embryos. Specifically, enteric and DRG-precursors differentiate into neurons in the anterior gut and trunk respectively, while enteric and DRG neurons are rarely present in the posterior gut and tail. Sympathetic neuron precursors are specified in hdac1(b382) mutants and they undergo generic neuronal differentiation but fail to undergo noradrenergic differentiation. Using the HDAC inhibitor TSA, we isolated enzyme activity and temporal requirements for HDAC function that reproduce hdac1(b382) defects in craniofacial and sympathetic neuron development. Our study reveals distinct functional and temporal requirements for zebrafish hdac1 during neural crest-derived craniofacial and peripheral neuron development.

  18. The Specification of Cortical Subcerebral Projection Neurons Depends on the Direct Repression of TBR1 by CTIP1/BCL11a.

    Science.gov (United States)

    Cánovas, José; Berndt, F Andrés; Sepúlveda, Hugo; Aguilar, Rodrigo; Veloso, Felipe A; Montecino, Martín; Oliva, Carlos; Maass, Juan C; Sierralta, Jimena; Kukuljan, Manuel

    2015-05-13

    The acquisition of distinct neuronal fates is fundamental for the function of the cerebral cortex. We find that the development of subcerebral projections from layer 5 neurons in the mouse neocortex depends on the high levels of expression of the transcription factor CTIP1; CTIP1 is coexpressed with CTIP2 in neurons that project to subcerebral targets and with SATB2 in those that project to the contralateral cortex. CTIP1 directly represses Tbr1 in layer 5, which appears as a critical step for the acquisition of the subcerebral fate. In contrast, lower levels of CTIP1 in layer 6 are required for TBR1 expression, which directs the corticothalamic fate. CTIP1 does not appear to play a critical role in the acquisition of the callosal projection fate in layer 5. These findings unravel a key step in the acquisition of cell fate for closely related corticofugal neurons and indicate that differential dosages of transcriptions factors are critical to specify different neuronal identities. Copyright © 2015 the authors 0270-6474/15/357552-13$15.00/0.

  19. CCAR1 is required for Ngn3-mediated endocrine differentiation

    International Nuclear Information System (INIS)

    Lu, Chung-Kuang; Lai, Yi-Chyi; Lin, Yung-Fu; Chen, Hau-Ren; Chiang, Ming-Ko

    2012-01-01

    Highlights: ► We identify CCAR1 to directly interact with Ngn3. ► CCAR1 is co-localized with Ngn3 in the nucleus. ► CCAR1 cooperates with Ngn3 in activating NeuroD expression. ► CCAR1 is required for Ngn3-mediated PANC-1 transdifferentiation. -- Abstract: Neurogenin3 (Ngn3) is a basic helix-loop-helix transcription factor that specifies pancreatic endocrine cell fates during pancreas development. It can also initiate a transdifferentiation program when expressed in pancreatic exocrine and ductal cells. However, how Ngn3 initiates a transcriptional cascade to achieve endocrine differentiation is still poorly understood. Here, we show that cell cycle and apoptosis regulator 1 (CCAR1), which is a transcriptional coactivator for nuclear receptors, also interacts with Ngn3. The association between Ngn3 and CCAR1 was verified by pull-down assays and co-immunoprecipitation analyses. Using gene reporter assays, we found that CCAR1 is essential for Ngn3 to activate the expression of the reporter genes containing the NeuroD promoter. Moreover, down-regulation of endogenous CCAR1 in the PANC-1 pancreatic ductal cell line inhibits the transdifferentiation program initiated by Ngn3. CCAR1 is, therefore, a novel partner of Ngn3 in mediating endocrine differentiation.

  20. Asymmetric cell division and Notch signaling specify dopaminergic neurons in Drosophila.

    Directory of Open Access Journals (Sweden)

    Murni Tio

    Full Text Available In Drosophila, dopaminergic (DA neurons can be found from mid embryonic stages of development till adulthood. Despite their functional involvement in learning and memory, not much is known about the developmental as well as molecular mechanisms involved in the events of DA neuronal specification, differentiation and maturation. In this report we demonstrate that most larval DA neurons are generated during embryonic development. Furthermore, we show that loss of function (l-o-f mutations of genes of the apical complex proteins in the asymmetric cell division (ACD machinery, such as inscuteable and bazooka result in supernumerary DA neurons, whereas l-o-f mutations of genes of the basal complex proteins such as numb result in loss or reduction of DA neurons. In addition, when Notch signaling is reduced or abolished, additional DA neurons are formed and conversely, when Notch signaling is activated, less DA neurons are generated. Our data demonstrate that both ACD and Notch signaling are crucial mechanisms for DA neuronal specification. We propose a model in which ACD results in differential Notch activation in direct siblings and in this context Notch acts as a repressor for DA neuronal specification in the sibling that receives active Notch signaling. Our study provides the first link of ACD and Notch signaling in the specification of a neurotransmitter phenotype in Drosophila. Given the high degree of conservation between Drosophila and vertebrate systems, this study could be of significance to mechanisms of DA neuronal differentiation not limited to flies.

  1. Valproic Acid Arrests Proliferation but Promotes Neuronal Differentiation of Adult Spinal NSPCs from SCI Rats.

    Science.gov (United States)

    Chu, Weihua; Yuan, Jichao; Huang, Lei; Xiang, Xin; Zhu, Haitao; Chen, Fei; Chen, Yanyan; Lin, Jiangkai; Feng, Hua

    2015-07-01

    Although the adult spinal cord contains a population of multipotent neural stem/precursor cells (NSPCs) exhibiting the potential to replace neurons, endogenous neurogenesis is very limited after spinal cord injury (SCI) because the activated NSPCs primarily differentiate into astrocytes rather than neurons. Valproic acid (VPA), a histone deacetylase inhibitor, exerts multiple pharmacological effects including fate regulation of stem cells. In this study, we cultured adult spinal NSPCs from chronic compressive SCI rats and treated with VPA. In spite of inhibiting the proliferation and arresting in the G0/G1 phase of NSPCs, VPA markedly promoted neuronal differentiation (β-tubulin III(+) cells) as well as decreased astrocytic differentiation (GFAP(+) cells). Cell cycle regulator p21(Cip/WAF1) and proneural genes Ngn2 and NeuroD1 were increased in the two processes respectively. In vivo, to minimize the possible inhibitory effects of VPA to the proliferation of NSPCs as well as avoid other neuroprotections of VPA in acute phase of SCI, we carried out a delayed intraperitoneal injection of VPA (150 mg/kg/12 h) to SCI rats from day 15 to day 22 after injury. Both of the newborn neuron marker doublecortin and the mature neuron marker neuron-specific nuclear protein were significantly enhanced after VPA treatment in the epicenter and adjacent segments of the injured spinal cord. Although the impaired corticospinal tracks had not significantly improved, Basso-Beattie-Bresnahan scores in VPA treatment group were better than control. Our study provide the first evidence that administration of VPA enhances the neurogenic potential of NSPCs after SCI and reveal the therapeutic value of delayed treatment of VPA to SCI.

  2. Merkel Cell-Driven BDNF Signaling Specifies SAI Neuron Molecular and Electrophysiological Phenotypes.

    Science.gov (United States)

    Reed-Geaghan, Erin G; Wright, Margaret C; See, Lauren A; Adelman, Peter C; Lee, Kuan Hsien; Koerber, H Richard; Maricich, Stephen M

    2016-04-13

    The extent to which the skin instructs peripheral somatosensory neuron maturation is unknown. We studied this question in Merkel cell-neurite complexes, where slowly adapting type I (SAI) neurons innervate skin-derived Merkel cells. Transgenic mice lacking Merkel cells had normal dorsal root ganglion (DRG) neuron numbers, but fewer DRG neurons expressed the SAI markers TrkB, TrkC, and Ret. Merkel cell ablation also decreased downstream TrkB signaling in DRGs, and altered the expression of genes associated with SAI development and function. Skin- and Merkel cell-specific deletion of Bdnf during embryogenesis, but not postnatal Bdnf deletion or Ntf3 deletion, reproduced these results. Furthermore, prototypical SAI electrophysiological signatures were absent from skin regions where Bdnf was deleted in embryonic Merkel cells. We conclude that BDNF produced by Merkel cells during a precise embryonic period guides SAI neuron development, providing the first direct evidence that the skin instructs sensory neuron molecular and functional maturation. Peripheral sensory neurons show incredible phenotypic and functional diversity that is initiated early by cell-autonomous and local environmental factors found within the DRG. However, the contribution of target tissues to subsequent sensory neuron development remains unknown. We show that Merkel cells are required for the molecular and functional maturation of the SAI neurons that innervate them. We also show that this process is controlled by BDNF signaling. These findings provide new insights into the regulation of somatosensory neuron development and reveal a novel way in which Merkel cells participate in mechanosensation. Copyright © 2016 the authors 0270-6474/16/364362-15$15.00/0.

  3. Hierarchical axon targeting of Drosophila olfactory receptor neurons specified by the proneural transcription factors Atonal and Amos.

    Science.gov (United States)

    Okumura, Misako; Kato, Tomoko; Miura, Masayuki; Chihara, Takahiro

    2016-01-01

    Sensory information is spatially represented in the brain to form a neural map. It has been suggested that axon-axon interactions are important for neural map formation; however, the underlying mechanisms are not fully understood. We used the Drosophila antennal lobe, the first olfactory center in the brain, as a model for studying neural map formation. Olfactory receptor neurons (ORNs) expressing the same odorant receptor target their axons to a single glomerulus out of approximately 50 glomeruli in the antennal lobe. Previous studies have showed that the axons of Atonal ORNs, specified by Atonal, a basic helix-loop-helix (bHLH) transcription factor, pioneer antennal lobe formation; however, the details remain to be elucidated. Here, we show that genetic ablation of Atonal ORNs affects antennal lobe structure and axon targeting of Amos ORNs, another type of ORN specified by the bHLH transcription factor Amos. During development, Atonal ORNs reach the antennal lobe and form the axon commissure before Amos ORNs. We also found that N-cadherin knockdown specifically in Atonal ORNs disrupts the glomerular boundary in the whole antennal lobe. Our results suggest that Atonal ORNs function as pioneer axons. Thus, correct axon targeting of Atonal ORNs is essential for formation of the whole antennal lobe. © 2015 The Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd.

  4. Divergent functions of the proneural genes Mash1 and Ngn2 in the specification of neuronal subtype identity

    Science.gov (United States)

    Parras, Carlos M.; Schuurmans, Carol; Scardigli, Raffaella; Kim, Jaesang; Anderson, David J.; Guillemot, François

    2002-01-01

    The neural bHLH genes Mash1 and Ngn2 are expressed in complementary populations of neural progenitors in the central and peripheral nervous systems. Here, we have systematically compared the activities of the two genes during neural development by generating replacement mutations in mice in which the coding sequences of Mash1 and Ngn2 were swapped. Using this approach, we demonstrate that Mash1 has the capacity to respecify the identity of neuronal populations normally derived from Ngn2-expressing progenitors in the dorsal telencephalon and ventral spinal cord. In contrast, misexpression of Ngn2 in Mash1-expressing progenitors does not result in any overt change in neuronal phenotype. Taken together, these results demonstrate that Mash1 and Ngn2 have divergent functions in specification of neuronal subtype identity, with Mash1 having the characteristics of an instructive determinant whereas Ngn2 functions as a permissive factor that must act in combination with other factors to specify neuronal phenotypes. Moreover, the ectopic expression of Ngn2 can rescue the neurogenesis defects of Mash1 null mutants in the ventral telencephalon and sympathetic ganglia but not in the ventral spinal cord and the locus coeruleus, indicating that Mash1 contribution to the specification of neuronal fates varies greatly in different lineages, presumably depending on the presence of other determinants of neuronal identity. PMID:11825874

  5. Parvalbumin+ Neurons and Npas1+ Neurons Are Distinct Neuron Classes in the Mouse External Globus Pallidus.

    Science.gov (United States)

    Hernández, Vivian M; Hegeman, Daniel J; Cui, Qiaoling; Kelver, Daniel A; Fiske, Michael P; Glajch, Kelly E; Pitt, Jason E; Huang, Tina Y; Justice, Nicholas J; Chan, C Savio

    2015-08-26

    Compelling evidence suggests that pathological activity of the external globus pallidus (GPe), a nucleus in the basal ganglia, contributes to the motor symptoms of a variety of movement disorders such as Parkinson's disease. Recent studies have challenged the idea that the GPe comprises a single, homogenous population of neurons that serves as a simple relay in the indirect pathway. However, we still lack a full understanding of the diversity of the neurons that make up the GPe. Specifically, a more precise classification scheme is needed to better describe the fundamental biology and function of different GPe neuron classes. To this end, we generated a novel multicistronic BAC (bacterial artificial chromosome) transgenic mouse line under the regulatory elements of the Npas1 gene. Using a combinatorial transgenic and immunohistochemical approach, we discovered that parvalbumin-expressing neurons and Npas1-expressing neurons in the GPe represent two nonoverlapping cell classes, amounting to 55% and 27% of the total GPe neuron population, respectively. These two genetically identified cell classes projected primarily to the subthalamic nucleus and to the striatum, respectively. Additionally, parvalbumin-expressing neurons and Npas1-expressing neurons were distinct in their autonomous and driven firing characteristics, their expression of intrinsic ion conductances, and their responsiveness to chronic 6-hydroxydopamine lesion. In summary, our data argue that parvalbumin-expressing neurons and Npas1-expressing neurons are two distinct functional classes of GPe neurons. This work revises our understanding of the GPe, and provides the foundation for future studies of its function and dysfunction. Until recently, the heterogeneity of the constituent neurons within the external globus pallidus (GPe) was not fully appreciated. We addressed this knowledge gap by discovering two principal GPe neuron classes, which were identified by their nonoverlapping expression of the

  6. Parvalbumin+ Neurons and Npas1+ Neurons Are Distinct Neuron Classes in the Mouse External Globus Pallidus

    Science.gov (United States)

    Hernández, Vivian M.; Hegeman, Daniel J.; Cui, Qiaoling; Kelver, Daniel A.; Fiske, Michael P.; Glajch, Kelly E.; Pitt, Jason E.; Huang, Tina Y.; Justice, Nicholas J.

    2015-01-01

    Compelling evidence suggests that pathological activity of the external globus pallidus (GPe), a nucleus in the basal ganglia, contributes to the motor symptoms of a variety of movement disorders such as Parkinson's disease. Recent studies have challenged the idea that the GPe comprises a single, homogenous population of neurons that serves as a simple relay in the indirect pathway. However, we still lack a full understanding of the diversity of the neurons that make up the GPe. Specifically, a more precise classification scheme is needed to better describe the fundamental biology and function of different GPe neuron classes. To this end, we generated a novel multicistronic BAC (bacterial artificial chromosome) transgenic mouse line under the regulatory elements of the Npas1 gene. Using a combinatorial transgenic and immunohistochemical approach, we discovered that parvalbumin-expressing neurons and Npas1-expressing neurons in the GPe represent two nonoverlapping cell classes, amounting to 55% and 27% of the total GPe neuron population, respectively. These two genetically identified cell classes projected primarily to the subthalamic nucleus and to the striatum, respectively. Additionally, parvalbumin-expressing neurons and Npas1-expressing neurons were distinct in their autonomous and driven firing characteristics, their expression of intrinsic ion conductances, and their responsiveness to chronic 6-hydroxydopamine lesion. In summary, our data argue that parvalbumin-expressing neurons and Npas1-expressing neurons are two distinct functional classes of GPe neurons. This work revises our understanding of the GPe, and provides the foundation for future studies of its function and dysfunction. SIGNIFICANCE STATEMENT Until recently, the heterogeneity of the constituent neurons within the external globus pallidus (GPe) was not fully appreciated. We addressed this knowledge gap by discovering two principal GPe neuron classes, which were identified by their nonoverlapping

  7. Complexity of hierarchically and 1-dimensional periodically specified problems

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    Marathe, M.V.; Hunt, H.B. III; Stearns, R.E.; Radhakrishnan, V.

    1995-08-23

    We study the complexity of various combinatorial and satisfiability problems when instances are specified using one of the following specifications: (1) the 1-dimensional finite periodic narrow specifications of Wanke and Ford et al. (2) the 1-dimensional finite periodic narrow specifications with explicit boundary conditions of Gale (3) the 2-way infinite1-dimensional narrow periodic specifications of Orlin et al. and (4) the hierarchical specifications of Lengauer et al. we obtain three general types of results. First, we prove that there is a polynomial time algorithm that given a 1-FPN- or 1-FPN(BC)specification of a graph (or a C N F formula) constructs a level-restricted L-specification of an isomorphic graph (or formula). This theorem along with the hardness results proved here provides alternative and unified proofs of many hardness results proved in the past either by Lengauer and Wagner or by Orlin. Second, we study the complexity of generalized CNF satisfiability problems of Schaefer. Assuming P {ne} PSPACE, we characterize completely the polynomial time solvability of these problems, when instances are specified as in (1), (2),(3) or (4). As applications of our first two types of results, we obtain a number of new PSPACE-hardness and polynomial time algorithms for problems specified as in (1), (2), (3) or(4). Many of our results also hold for O(log N) bandwidth bounded planar instances.

  8. Pαx6 expression in postmitotic neurons mediates the growth of axons in response to SFRP1.

    Directory of Open Access Journals (Sweden)

    Alvaro Sebastián-Serrano

    Full Text Available During development, the mechanisms that specify neuronal subclasses are coupled to those that determine their axonal response to guidance cues. Pax6 is a homedomain transcription factor required for the specification of a variety of neural precursors. After cell cycle exit, Pax6 expression is often shut down in the precursor progeny and most postmitotic neurons no longer express detectable levels of the protein. There are however exceptions and high Pax6 protein levels are found, for example, in postmitotic retinal ganglion cells (RGCs, dopaminergic neurons of the olfactory bulb and the limbic system in the telencephalon. The function of Pax6 in these differentiating neurons remains mostly elusive. Here, we demonstrate that Pax6 mediates the response of growing axons to SFRP1, a secreted molecule expressed in several Pax6-positive forebrain territories. Forced expression of Pax6 in cultured postmitotic cortical neurons, which do not normally express Pax6, was sufficient to increment axonal length. Growth was blocked by the addition of anti-SFRP1 antibodies, whereas exogenously added SFRP1 increased axonal growth of Pax6-transfected neurons but not that of control or untransfected cortical neurons. In the reverse scenario, shRNA-mediated knock-down of Pax6 in mouse retinal explants specifically abolished RGCs axonal growth induced by SFRP1, but had no effect on RGCs differentiation and it did not modify the effect of Shh or Netrin on axon growth. Taken together these results demonstrate that expression of Pax6 is necessary and sufficient to render postmitotic neurons competent to respond to SFRP1. These results reveal a novel and unexpected function of Pax6 in postmitotic neurons and situate Pax6 and SFRP1 as pair regulators of axonal connectivity.

  9. Zebrafish transgenic constructs label specific neurons in Xenopus laevis spinal cord and identify frog V0v spinal neurons.

    Science.gov (United States)

    Juárez-Morales, José L; Martinez-De Luna, Reyna I; Zuber, Michael E; Roberts, Alan; Lewis, Katharine E

    2017-09-01

    A correctly functioning spinal cord is crucial for locomotion and communication between body and brain but there are fundamental gaps in our knowledge of how spinal neuronal circuitry is established and functions. To understand the genetic program that regulates specification and functions of this circuitry, we need to connect neuronal molecular phenotypes with physiological analyses. Studies using Xenopus laevis tadpoles have increased our understanding of spinal cord neuronal physiology and function, particularly in locomotor circuitry. However, the X. laevis tetraploid genome and long generation time make it difficult to investigate how neurons are specified. The opacity of X. laevis embryos also makes it hard to connect functional classes of neurons and the genes that they express. We demonstrate here that Tol2 transgenic constructs using zebrafish enhancers that drive expression in specific zebrafish spinal neurons label equivalent neurons in X. laevis and that the incorporation of a Gal4:UAS amplification cassette enables cells to be observed in live X. laevis tadpoles. This technique should enable the molecular phenotypes, morphologies and physiologies of distinct X. laevis spinal neurons to be examined together in vivo. We have used an islet1 enhancer to label Rohon-Beard sensory neurons and evx enhancers to identify V0v neurons, for the first time, in X. laevis spinal cord. Our work demonstrates the homology of spinal cord circuitry in zebrafish and X. laevis, suggesting that future work could combine their relative strengths to elucidate a more complete picture of how vertebrate spinal cord neurons are specified, and function to generate behavior. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1007-1020, 2017. © 2017 Wiley Periodicals, Inc.

  10. Sensory Neuron Fates Are Distinguished by a Transcriptional Switch that Regulates Dendrite Branch Stabilization

    Science.gov (United States)

    Smith, Cody J.; O’Brien, Timothy; Chatzigeorgiou, Marios; Spencer, W. Clay; Feingold-Link, Elana; Husson, Steven J.; Hori, Sayaka; Mitani, Shohei; Gottschalk, Alexander; Schafer, William R.; Miller, David M.

    2013-01-01

    SUMMARY Sensory neurons adopt distinct morphologies and functional modalities to mediate responses to specific stimuli. Transcription factors and their downstream effectors orchestrate this outcome but are incompletely defined. Here, we show that different classes of mechanosensory neurons in C. elegans are distinguished by the combined action of the transcription factors MEC-3, AHR-1, and ZAG-1. Low levels of MEC-3 specify the elaborate branching pattern of PVD nociceptors, whereas high MEC-3 is correlated with the simple morphology of AVM and PVM touch neurons. AHR-1 specifies AVM touch neuron fate by elevating MEC-3 while simultaneously blocking expression of nociceptive genes such as the MEC-3 target, the claudin-like membrane protein HPO-30, that promotes the complex dendritic branching pattern of PVD. ZAG-1 exercises a parallel role to prevent PVM from adopting the PVD fate. The conserved dendritic branching function of the Drosophila AHR-1 homolog, Spineless, argues for similar pathways in mammals. PMID:23889932

  11. A New Method for Generating Insulin-Secreting Cells from Human Pancreatic Epithelial Cells After Islet Isolation Transformed by NeuroD1

    Science.gov (United States)

    Shimoda, Masayuki; Chen, Shuyuan; Noguchi, Hirofumi; Takita, Morihito; Sugimoto, Koji; Itoh, Takeshi; Chujo, Daisuke; Iwahashi, Shuichi; Naziruddin, Bashoo; Levy, Marlon F.

    2014-01-01

    Abstract The generation of insulin-secreting cells from nonendocrine pancreatic epithelial cells (NEPEC) has been demonstrated for potential clinical use in the treatment of diabetes. However, previous methods either had limited efficacy or required viral vectors, which hinder clinical application. In this study, we aimed to establish an efficient method of insulin-secreting cell generation from NEPEC without viral vectors. We used nonislet fractions from both research-grade human pancreata from brain-dead donors and clinical pancreata after total pancreatectomy with autologous islet transplantation to treat chronic pancreatitis. It is of note that a few islets could be mingled in the nonislet fractions, but their influence could be limited. The NeuroD1 gene was induced into NEPEC using an effective triple lipofection method without viral vectors to generate insulin-secreting cells. The differentiation was promoted by adding a growth factor cocktail into the culture medium. Using the research-grade human pancreata, the effective method showed high efficacy in the differentiation of NEPEC into insulin-positive cells that secreted insulin in response to a glucose challenge and improved diabetes after being transplanted into diabetic athymic mice. Using the clinical pancreata, similar efficacy was obtained, even though those pancreata suffered chronic pancreatitis. In conclusion, our effective differentiation protocol with triple lipofection method enabled us to achieve very efficient insulin-secreting cell generation from human NEPEC without viral vectors. This method offers the potential for supplemental insulin-secreting cell transplantation for both allogeneic and autologous islet transplantation. PMID:24845703

  12. A distance constrained synaptic plasticity model of C. elegans neuronal network

    Science.gov (United States)

    Badhwar, Rahul; Bagler, Ganesh

    2017-03-01

    Brain research has been driven by enquiry for principles of brain structure organization and its control mechanisms. The neuronal wiring map of C. elegans, the only complete connectome available till date, presents an incredible opportunity to learn basic governing principles that drive structure and function of its neuronal architecture. Despite its apparently simple nervous system, C. elegans is known to possess complex functions. The nervous system forms an important underlying framework which specifies phenotypic features associated to sensation, movement, conditioning and memory. In this study, with the help of graph theoretical models, we investigated the C. elegans neuronal network to identify network features that are critical for its control. The 'driver neurons' are associated with important biological functions such as reproduction, signalling processes and anatomical structural development. We created 1D and 2D network models of C. elegans neuronal system to probe the role of features that confer controllability and small world nature. The simple 1D ring model is critically poised for the number of feed forward motifs, neuronal clustering and characteristic path-length in response to synaptic rewiring, indicating optimal rewiring. Using empirically observed distance constraint in the neuronal network as a guiding principle, we created a distance constrained synaptic plasticity model that simultaneously explains small world nature, saturation of feed forward motifs as well as observed number of driver neurons. The distance constrained model suggests optimum long distance synaptic connections as a key feature specifying control of the network.

  13. Conserved gene regulatory module specifies lateral neural borders across bilaterians.

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    Li, Yongbin; Zhao, Di; Horie, Takeo; Chen, Geng; Bao, Hongcun; Chen, Siyu; Liu, Weihong; Horie, Ryoko; Liang, Tao; Dong, Biyu; Feng, Qianqian; Tao, Qinghua; Liu, Xiao

    2017-08-01

    The lateral neural plate border (NPB), the neural part of the vertebrate neural border, is composed of central nervous system (CNS) progenitors and peripheral nervous system (PNS) progenitors. In invertebrates, PNS progenitors are also juxtaposed to the lateral boundary of the CNS. Whether there are conserved molecular mechanisms determining vertebrate and invertebrate lateral neural borders remains unclear. Using single-cell-resolution gene-expression profiling and genetic analysis, we present evidence that orthologs of the NPB specification module specify the invertebrate lateral neural border, which is composed of CNS and PNS progenitors. First, like in vertebrates, the conserved neuroectoderm lateral border specifier Msx/vab-15 specifies lateral neuroblasts in Caenorhabditis elegans Second, orthologs of the vertebrate NPB specification module ( Msx/vab-15 , Pax3/7/pax-3 , and Zic/ref-2 ) are significantly enriched in worm lateral neuroblasts. In addition, like in other bilaterians, the expression domain of Msx/vab-15 is more lateral than those of Pax3/7/pax-3 and Zic/ref- 2 in C. elegans Third, we show that Msx/vab-15 regulates the development of mechanosensory neurons derived from lateral neural progenitors in multiple invertebrate species, including C. elegans , Drosophila melanogaster , and Ciona intestinalis We also identify a novel lateral neural border specifier, ZNF703/tlp-1 , which functions synergistically with Msx/vab- 15 in both C. elegans and Xenopus laevis These data suggest a common origin of the molecular mechanism specifying lateral neural borders across bilaterians.

  14. Target-specific M1 inputs to infragranular S1 pyramidal neurons

    Science.gov (United States)

    Fanselow, Erika E.; Simons, Daniel J.

    2016-01-01

    The functional role of input from the primary motor cortex (M1) to primary somatosensory cortex (S1) is unclear; one key to understanding this pathway may lie in elucidating the cell-type specific microcircuits that connect S1 and M1. Recently, we discovered that a subset of pyramidal neurons in the infragranular layers of S1 receive especially strong input from M1 (Kinnischtzke AK, Simons DJ, Fanselow EE. Cereb Cortex 24: 2237–2248, 2014), suggesting that M1 may affect specific classes of pyramidal neurons differently. Here, using combined optogenetic and retrograde labeling approaches in the mouse, we examined the strengths of M1 inputs to five classes of infragranular S1 neurons categorized by their projections to particular cortical and subcortical targets. We found that the magnitude of M1 synaptic input to S1 pyramidal neurons varies greatly depending on the projection target of the postsynaptic neuron. Of the populations examined, M1-projecting corticocortical neurons in L6 received the strongest M1 inputs, whereas ventral posterior medial nucleus-projecting corticothalamic neurons, also located in L6, received the weakest. Each population also possessed distinct intrinsic properties. The results suggest that M1 differentially engages specific classes of S1 projection neurons, thereby regulating the motor-related influence S1 exerts over subcortical structures. PMID:27334960

  15. Engrafted human induced pluripotent stem cell-derived anterior specified neural progenitors protect the rat crushed optic nerve.

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    Leila Satarian

    Full Text Available BACKGROUND: Degeneration of retinal ganglion cells (RGCs is a common occurrence in several eye diseases. This study examined the functional improvement and protection of host RGCs in addition to the survival, integration and neuronal differentiation capabilities of anterior specified neural progenitors (NPs following intravitreal transplantation. METHODOLOGY/PRINCIPAL FINDINGS: NPs were produced under defined conditions from human induced pluripotent stem cells (hiPSCs and transplanted into rats whose optic nerves have been crushed (ONC. hiPSCs were induced to differentiate into anterior specified NPs by the use of Noggin and retinoic acid. The hiPSC-NPs were labeled by green fluorescent protein or a fluorescent tracer 1,1' -dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI and injected two days after induction of ONC in hooded rats. Functional analysis according to visual evoked potential recordings showed significant amplitude recovery in animals transplanted with hiPSC-NPs. Retrograde labeling by an intra-collicular DiI injection showed significantly higher numbers of RGCs and spared axons in ONC rats treated with hiPSC-NPs or their conditioned medium (CM. The analysis of CM of hiPSC-NPs showed the secretion of ciliary neurotrophic factor, basic fibroblast growth factor, and insulin-like growth factor. Optic nerve of cell transplanted groups also had increased GAP43 immunoreactivity and myelin staining by FluoroMyelin™ which imply for protection of axons and myelin. At 60 days post-transplantation hiPSC-NPs were integrated into the ganglion cell layer of the retina and expressed neuronal markers. CONCLUSIONS/SIGNIFICANCE: The transplantation of anterior specified NPs may improve optic nerve injury through neuroprotection and differentiation into neuronal lineages. These NPs possibly provide a promising new therapeutic approach for traumatic optic nerve injuries and loss of RGCs caused by other diseases.

  16. The role of the transcription factor Rbpj in the development of dorsal root ganglia

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    Chen Jia-Yin

    2011-04-01

    Full Text Available Abstract Background The dorsal root ganglion (DRG is composed of well-characterized populations of sensory neurons and glia derived from a common pool of neural crest stem cells (NCCs, and is a good system to study the mechanisms of neurogenesis and gliogenesis. Notch signaling is known to play important roles in DRG development, but the full scope of Notch functions in mammalian DRG development remains poorly understood. Results In the present study, we used Wnt1-Cre to conditionally inactivate the transcription factor Rbpj, a critical integrator of activation signals from all Notch receptors, in NCCs and their derived cells. Deletion of Rbpj caused the up-regulation of NeuroD1 and precocious neurogenesis in DRG early development but led to an eventual deficit of sensory neurons at later stages, due to reduced cell proliferation and abnormal cell death. In addition, gliogenesis was delayed initially, but a near-complete loss of glia was observed finally in Rbpj-deficient DRG. Furthermore, we found P75 and Sox10, which are normally expressed exclusively in neuronal and glial progenitors of the DRG after the NCCs have completed their migration, were co-expressed in many cells of the DRG of Rbpj conditional knock-out mice. Conclusions Our data indicate that Rbpj-mediated canonical Notch signaling inhibits DRG neuronal differentiation, possibly by regulating NeuroD1 expression, and is required for DRG gliogenesis in vivo.

  17. Conversion of MyoD to a Neurogenic Factor: Binding Site Specificity Determines Lineage

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    Abraham P. Fong

    2015-03-01

    Full Text Available MyoD and NeuroD2, master regulators of myogenesis and neurogenesis, bind to a “shared” E-box sequence (CAGCTG and a “private” sequence (CAGGTG or CAGATG, respectively. To determine whether private-site recognition is sufficient to confer lineage specification, we generated a MyoD mutant with the DNA-binding specificity of NeuroD2. This chimeric mutant gained binding to NeuroD2 private sites but maintained binding to a subset of MyoD-specific sites, activating part of both the muscle and neuronal programs. Sequence analysis revealed an enrichment for PBX/MEIS motifs at the subset of MyoD-specific sites bound by the chimera, and point mutations that prevent MyoD interaction with PBX/MEIS converted the chimera to a pure neurogenic factor. Therefore, redirecting MyoD binding from MyoD private sites to NeuroD2 private sites, despite preserved binding to the MyoD/NeuroD2 shared sites, is sufficient to change MyoD from a master regulator of myogenesis to a master regulator of neurogenesis.

  18. Activity of Tachykinin1-Expressing Pet1 Raphe Neurons Modulates the Respiratory Chemoreflex.

    Science.gov (United States)

    Hennessy, Morgan L; Corcoran, Andrea E; Brust, Rachael D; Chang, YoonJeung; Nattie, Eugene E; Dymecki, Susan M

    2017-02-15

    Homeostatic control of breathing, heart rate, and body temperature relies on circuits within the brainstem modulated by the neurotransmitter serotonin (5-HT). Mounting evidence points to specialized neuronal subtypes within the serotonergic neuronal system, borne out in functional studies, for the modulation of distinct facets of homeostasis. Such functional differences, read out at the organismal level, are likely subserved by differences among 5-HT neuron subtypes at the cellular and molecular levels, including differences in the capacity to coexpress other neurotransmitters such as glutamate, GABA, thyrotropin releasing hormone, and substance P encoded by the Tachykinin-1 ( Tac1 ) gene. Here, we characterize in mice a 5-HT neuron subtype identified by expression of Tac1 and the serotonergic transcription factor gene Pet1 , referred to as the Tac1-Pet1 neuron subtype. Transgenic cell labeling showed Tac1-Pet1 soma resident largely in the caudal medulla. Chemogenetic [clozapine -N- oxide (CNO)-hM4Di] perturbation of Tac1-Pet1 neuron activity blunted the ventilatory response of the respiratory CO 2 chemoreflex, which normally augments ventilation in response to hypercapnic acidosis to restore normal pH and PCO 2 Tac1-Pet1 axonal boutons were found localized to brainstem areas implicated in respiratory modulation, with highest density in motor regions. These findings demonstrate that the activity of a Pet1 neuron subtype with the potential to release both 5-HT and substance P is necessary for normal respiratory dynamics, perhaps via motor outputs that engage muscles of respiration and maintain airway patency. These Tac1-Pet1 neurons may act downstream of Egr2-Pet1 serotonergic neurons, which were previously established in respiratory chemoreception, but do not innervate respiratory motor nuclei. SIGNIFICANCE STATEMENT Serotonin (5-HT) neurons modulate physiological processes and behaviors as diverse as body temperature, respiration, aggression, and mood. Using

  19. Neuronal Rac1 Is Required for Learning-Evoked Neurogenesis

    Science.gov (United States)

    Anderson, Matthew P.; Freewoman, Julia; Cord, Branden; Babu, Harish; Brakebusch, Cord

    2013-01-01

    Hippocampus-dependent learning and memory relies on synaptic plasticity as well as network adaptations provided by the addition of adult-born neurons. We have previously shown that activity-induced intracellular signaling through the Rho family small GTPase Rac1 is necessary in forebrain projection neurons for normal synaptic plasticity in vivo, and here we show that selective loss of neuronal Rac1 also impairs the learning-evoked increase in neurogenesis in the adult mouse hippocampus. Earlier work has indicated that experience elevates the abundance of adult-born neurons in the hippocampus primarily by enhancing the survival of neurons produced just before the learning event. Loss of Rac1 in mature projection neurons did reduce learning-evoked neurogenesis but, contrary to our expectations, these effects were not mediated by altering the survival of young neurons in the hippocampus. Instead, loss of neuronal Rac1 activation selectively impaired a learning-evoked increase in the proliferation and accumulation of neural precursors generated during the learning event itself. This indicates that experience-induced alterations in neurogenesis can be mechanistically resolved into two effects: (1) the well documented but Rac1-independent signaling cascade that enhances the survival of young postmitotic neurons; and (2) a previously unrecognized Rac1-dependent signaling cascade that stimulates the proliferative production and retention of new neurons generated during learning itself. PMID:23884931

  20. Dnmt1-dependent Chk1 pathway suppression is protective against neuron division.

    Science.gov (United States)

    Oshikawa, Mio; Okada, Kei; Tabata, Hidenori; Nagata, Koh-Ichi; Ajioka, Itsuki

    2017-09-15

    Neuronal differentiation and cell-cycle exit are tightly coordinated, even in pathological situations. When pathological neurons re-enter the cell cycle and progress through the S phase, they undergo cell death instead of division. However, the mechanisms underlying mitotic resistance are mostly unknown. Here, we have found that acute inactivation of retinoblastoma (Rb) family proteins (Rb, p107 and p130) in mouse postmitotic neurons leads to cell death after S-phase progression. Checkpoint kinase 1 (Chk1) pathway activation during the S phase prevented the cell death, and allowed the division of cortical neurons that had undergone acute Rb family inactivation, oxygen-glucose deprivation (OGD) or in vivo hypoxia-ischemia. During neurogenesis, cortical neurons became protected from S-phase Chk1 pathway activation by the DNA methyltransferase Dnmt1, and underwent cell death after S-phase progression. Our results indicate that Chk1 pathway activation overrides mitotic safeguards and uncouples neuronal differentiation from mitotic resistance. © 2017. Published by The Company of Biologists Ltd.

  1. C1 neurons: the body's EMTs.

    Science.gov (United States)

    Guyenet, Patrice G; Stornetta, Ruth L; Bochorishvili, Genrieta; Depuy, Seth D; Burke, Peter G R; Abbott, Stephen B G

    2013-08-01

    The C1 neurons reside in the rostral and intermediate portions of the ventrolateral medulla (RVLM, IVLM). They use glutamate as a fast transmitter and synthesize catecholamines plus various neuropeptides. These neurons regulate the hypothalamic pituitary axis via direct projections to the paraventricular nucleus and regulate the autonomic nervous system via projections to sympathetic and parasympathetic preganglionic neurons. The presympathetic C1 cells, located in the RVLM, are probably organized in a roughly viscerotopic manner and most of them regulate the circulation. C1 cells are variously activated by hypoglycemia, infection or inflammation, hypoxia, nociception, and hypotension and contribute to most glucoprivic responses. C1 cells also stimulate breathing and activate brain stem noradrenergic neurons including the locus coeruleus. Based on the various effects attributed to the C1 cells, their axonal projections and what is currently known of their synaptic inputs, subsets of C1 cells appear to be differentially recruited by pain, hypoxia, infection/inflammation, hemorrhage, and hypoglycemia to produce a repertoire of stereotyped autonomic, metabolic, and neuroendocrine responses that help the organism survive physical injury and its associated cohort of acute infection, hypoxia, hypotension, and blood loss. C1 cells may also contribute to glucose and cardiovascular homeostasis in the absence of such physical stresses, and C1 cell hyperactivity may contribute to the increase in sympathetic nerve activity associated with diseases such as hypertension.

  2. C1 neurons: the body's EMTs

    Science.gov (United States)

    Stornetta, Ruth L.; Bochorishvili, Genrieta; DePuy, Seth D.; Burke, Peter G. R.; Abbott, Stephen B. G.

    2013-01-01

    The C1 neurons reside in the rostral and intermediate portions of the ventrolateral medulla (RVLM, IVLM). They use glutamate as a fast transmitter and synthesize catecholamines plus various neuropeptides. These neurons regulate the hypothalamic pituitary axis via direct projections to the paraventricular nucleus and regulate the autonomic nervous system via projections to sympathetic and parasympathetic preganglionic neurons. The presympathetic C1 cells, located in the RVLM, are probably organized in a roughly viscerotopic manner and most of them regulate the circulation. C1 cells are variously activated by hypoglycemia, infection or inflammation, hypoxia, nociception, and hypotension and contribute to most glucoprivic responses. C1 cells also stimulate breathing and activate brain stem noradrenergic neurons including the locus coeruleus. Based on the various effects attributed to the C1 cells, their axonal projections and what is currently known of their synaptic inputs, subsets of C1 cells appear to be differentially recruited by pain, hypoxia, infection/inflammation, hemorrhage, and hypoglycemia to produce a repertoire of stereotyped autonomic, metabolic, and neuroendocrine responses that help the organism survive physical injury and its associated cohort of acute infection, hypoxia, hypotension, and blood loss. C1 cells may also contribute to glucose and cardiovascular homeostasis in the absence of such physical stresses, and C1 cell hyperactivity may contribute to the increase in sympathetic nerve activity associated with diseases such as hypertension. PMID:23697799

  3. The PM1 neurons, movement sensitive centrifugal visual brain neurons in the locust: anatomy, physiology, and modulation by identified octopaminergic neurons.

    Science.gov (United States)

    Stern, Michael

    2009-02-01

    The locust's optic lobe contains a system of wide-field, multimodal, centrifugal neurons. Two of these cells, the protocerebrum-medulla-neurons PM4a and b, are octopaminergic. This paper describes a second pair of large centrifugal neurons (the protocerebrum-medulla-neurons PM1a and PM1b) from the brain of Locusta migratoria based on intracellular cobalt fills, electrophysiology, and immunocytochemistry. They originate and arborise in the central brain and send processes into the medulla of the optic lobe. Double intracellular recording from the same cell suggests input in the central brain and output in the optic lobe. The neurons show immunoreactivity to gamma-amino-butyric acid and its synthesising enzyme, glutamate decarboxylase. The PM1 cells are movement sensitive and show habituation to repeated visual stimulation. Bath application of octopamine causes the response to dishabituate. A very similar effect is produced by electrical stimulation of one of an octopaminergic PM4 neuron. This effect can be blocked by application of the octopamine antagonists, mianserin and phentolamine. This readily accessible system of four wide-field neurons provides a system suitable for the investigation of octopaminergic effects on the visual system at the cellular level.

  4. Persistence of the cell-cycle checkpoint kinase Wee1 in SadA- and SadB-deficient neurons disrupts neuronal polarity.

    Science.gov (United States)

    Müller, Myriam; Lutter, Daniela; Püschel, Andreas W

    2010-01-15

    Wee1 is well characterized as a cell-cycle checkpoint kinase that regulates the entry into mitosis in dividing cells. Here we identify a novel function of Wee1 in postmitotic neurons during the establishment of distinct axonal and dendritic compartments, which is an essential step during neuronal development. Wee1 is expressed in unpolarized neurons but is downregulated after neurons have extended an axon. Suppression of Wee1 impairs the formation of minor neurites but does not interfere with axon formation. However, neuronal polarity is disrupted when neurons fail to downregulate Wee1. The kinases SadA and SadB (Sad kinases) phosphorylate Wee1 and are required to initiate its downregulation in polarized neurons. Wee1 expression persists in neurons that are deficient in SadA and SadB and disrupts neuronal polarity. Knockdown of Wee1 rescues the Sada(-/-);Sadb(-/-) mutant phenotype and restores normal polarity in these neurons. Our results demonstrate that the regulation of Wee1 by SadA and SadB kinases is essential for the differentiation of polarized neurons.

  5. DRP1 Suppresses Leptin and Glucose Sensing of POMC Neurons.

    Science.gov (United States)

    Santoro, Anna; Campolo, Michela; Liu, Chen; Sesaki, Hiromi; Meli, Rosaria; Liu, Zhong-Wu; Kim, Jung Dae; Diano, Sabrina

    2017-03-07

    Hypothalamic pro-opiomelanocortin (POMC) neurons regulate energy and glucose metabolism. Intracellular mechanisms that enable these neurons to respond to changes in metabolic environment are ill defined. Here we show reduced expression of activated dynamin-related protein (pDRP1), a mitochondrial fission regulator, in POMC neurons of fed mice. These POMC neurons displayed increased mitochondrial size and aspect ratio compared to POMC neurons of fasted animals. Inducible deletion of DRP1 of mature POMC neurons (Drp1 fl/fl -POMC-cre:ER T2 ) resulted in improved leptin sensitivity and glucose responsiveness. In Drp1 fl/fl -POMC-cre:ER T2 mice, POMC neurons showed increased mitochondrial size, ROS production, and neuronal activation with increased expression of Kcnj11 mRNA regulated by peroxisome proliferator-activated receptor (PPAR). Furthermore, deletion of DRP1 enhanced the glucoprivic stimulus in these neurons, causing their stronger inhibition and a greater activation of counter-regulatory responses to hypoglycemia that were PPAR dependent. Together, these data unmasked a role for mitochondrial fission in leptin sensitivity and glucose sensing of POMC neurons. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. The role of mirror neurons in language acquisition and evolution.

    Science.gov (United States)

    Behme, Christina

    2014-04-01

    I argue that Cook et al.'s attack of the genetic hypothesis of mirror neurons misses its target because the authors miss the point that genetics may specify how neurons may learn, not what they learn. Paying more attention to recent work linking mirror neurons to language acquisition and evolution would strengthen Cook et al.'s arguments against a rigid genetic hypothesis.

  7. Dync1h1 Mutation Causes Proprioceptive Sensory Neuron Loss and Impaired Retrograde Axonal Transport of Dorsal Root Ganglion Neurons.

    Science.gov (United States)

    Zhao, Jing; Wang, Yi; Xu, Huan; Fu, Yuan; Qian, Ting; Bo, Deng; Lu, Yan-Xin; Xiong, Yi; Wan, Jun; Zhang, Xiang; Dong, Qiang; Chen, Xiang-Jun

    2016-07-01

    Sprawling (Swl) is a radiation-induced mutation which has been identified to have a nine base pair deletion in dynein heavy chain 1 (DYNC1H1: encoded by a single gene Dync1h1). This study is to investigate the phenotype and the underlying mechanism of the Dync1h1 mutant. To display the phenotype of Swl mutant mice, we examined the embryos of homozygous (Swl/Swl) and heterozygous (Swl/+) mice and their postnatal dorsal root ganglion (DRG) of surviving Swl/+ mice. The Swl/+ mice could survive for a normal life span, while Swl/Swl could only survive till embryonic (E) 8.5 days. Excessive apoptosis of Swl/+ DRG neurons was revealed during E11.5-E15.5 days, and the peak rate was at E13.5 days. In vitro study of mutated DRG neurons showed impaired retrograde transport of dynein-driven nerve growth factor (NGF). Mitochondria, another dynein-driven cargo, demonstrated much slower retrograde transport velocity in Swl/+ neurons than in wild-type (WT) neurons. Nevertheless, the Swl, Loa, and Cra mutations did not affect homodimerization of DYNC1H1. The Swl/Swl mutation of Dync1h1 gene led to embryonic mal-development and lethality, whereas the Swl/+ DRG neurons demonstrated deficient retrograde transport in dynein-driven cargos and excessive apoptosis during mid- to late-developmental stages. The underlying mechanism of the mutation may not be due to impaired homodimerization of DYNC1H1. © 2016 John Wiley & Sons Ltd.

  8. Glass promotes the differentiation of neuronal and non-neuronal cell types in the Drosophila eye

    Science.gov (United States)

    Morrison, Carolyn A.; Chen, Hao; Cook, Tiffany; Brown, Stuart

    2018-01-01

    Transcriptional regulators can specify different cell types from a pool of equivalent progenitors by activating distinct developmental programs. The Glass transcription factor is expressed in all progenitors in the developing Drosophila eye, and is maintained in both neuronal and non-neuronal cell types. Glass is required for neuronal progenitors to differentiate as photoreceptors, but its role in non-neuronal cone and pigment cells is unknown. To determine whether Glass activity is limited to neuronal lineages, we compared the effects of misexpressing it in neuroblasts of the larval brain and in epithelial cells of the wing disc. Glass activated overlapping but distinct sets of genes in these neuronal and non-neuronal contexts, including markers of photoreceptors, cone cells and pigment cells. Coexpression of other transcription factors such as Pax2, Eyes absent, Lozenge and Escargot enabled Glass to induce additional genes characteristic of the non-neuronal cell types. Cell type-specific glass mutations generated in cone or pigment cells using somatic CRISPR revealed autonomous developmental defects, and expressing Glass specifically in these cells partially rescued glass mutant phenotypes. These results indicate that Glass is a determinant of organ identity that acts in both neuronal and non-neuronal cells to promote their differentiation into functional components of the eye. PMID:29324767

  9. Isl1 is required for multiple aspects of motor neuron development.

    Science.gov (United States)

    Liang, Xingqun; Song, Mi-Ryoung; Xu, ZengGuang; Lanuza, Guillermo M; Liu, Yali; Zhuang, Tao; Chen, Yihan; Pfaff, Samuel L; Evans, Sylvia M; Sun, Yunfu

    2011-07-01

    The LIM homeodomain transcription factor Islet1 (Isl1) is expressed in multiple organs and plays essential roles during embryogenesis. Isl1 is required for the survival and specification of spinal cord motor neurons. Due to early embryonic lethality and loss of motor neurons, the role of Isl1 in other aspects of motor neuron development remains unclear. In this study, we generated Isl1 mutant mouse lines expressing graded doses of Isl1. Our study has revealed essential roles of Isl1 in multiple aspects of motor neuron development, including motor neuron cell body localization, motor column formation and axon growth. In addition, Isl1 is required for survival of cranial ganglia neurons. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Generation of Regionally Specified Neural Progenitors and Functional Neurons from Human Embryonic Stem Cells under Defined Conditions

    Directory of Open Access Journals (Sweden)

    Agnete Kirkeby

    2012-06-01

    Full Text Available To model human neural-cell-fate specification and to provide cells for regenerative therapies, we have developed a method to generate human neural progenitors and neurons from human embryonic stem cells, which recapitulates human fetal brain development. Through the addition of a small molecule that activates canonical WNT signaling, we induced rapid and efficient dose-dependent specification of regionally defined neural progenitors ranging from telencephalic forebrain to posterior hindbrain fates. Ten days after initiation of differentiation, the progenitors could be transplanted to the adult rat striatum, where they formed neuron-rich and tumor-free grafts with maintained regional specification. Cells patterned toward a ventral midbrain (VM identity generated a high proportion of authentic dopaminergic neurons after transplantation. The dopamine neurons showed morphology, projection pattern, and protein expression identical to that of human fetal VM cells grafted in parallel. VM-patterned but not forebrain-patterned neurons released dopamine and reversed motor deficits in an animal model of Parkinson's disease.

  11. Identification of Noncanonical Wnt Receptors Required for Wnt-3a-Induced Early Differentiation of Human Neural Stem Cells.

    Science.gov (United States)

    Bengoa-Vergniory, Nora; Gorroño-Etxebarria, Irantzu; López-Sánchez, Inmaculada; Marra, Michele; Di Chiaro, Pierluigi; Kypta, Robert

    2017-10-01

    Wnt proteins preferentially activate either β-catenin-dependent or β-catenin-independent signals, but the activity of a particular Wnt also depends on cellular context and receptor availability. We previously reported that Wnt-3a induces neural differentiation of human embryonic stem cell-derived neural stem cells (NSCs) in a β-catenin-independent manner by activating a signal involving JNK and the AP-1 family member ATF-2. Here, we report the results of a gene silencing approach to identify the Wnt receptors that mediate this response to Wnt-3a. Silencing of ROR2 increased neuronal differentiation, as measured by expression of the genes DCX, NEUROD1, and NGN1, suggesting ROR2 signals normally prevent differentiation. Silencing of the other Wnt receptors singly did not affect Wnt-3a-induced neuronal differentiation. However, pairwise silencing of ROR1 and FZD4 or FZD5 and of LRP6 and FZD4 or FZD5 inhibited neuronal differentiation, as detected by reductions in the expression of neuronal genes and immunocytochemical detection of DCX, NEUROD1 and DCX. Ectopic expression of these receptors in HEK 293 cells increased ATF2-dependent transcription. In addition, ROR1 coimmunoprecipitated with FZD4 and LRP6 in transfected HEK 293 cells and colocalized with FZD4 and with LRP6 at the cell surface of transfected L cells. Wnt-3a did not appear to affect these interactions but did alter the interactions between LRP6 and FZD4/5. Together, these observations highlight roles for ROR1, LRP6, FZD4, and FZD5 in neural stem cell differentiation and provide support for a model in which dynamic interactions among these receptors mediate Wnt-3a activation of ATF2 signaling.

  12. Rac1 regulates neuronal polarization through the WAVE complex

    DEFF Research Database (Denmark)

    Tahirovic, Sabina; Hellal, Farida; Neukirchen, Dorothee

    2010-01-01

    the physiological function of Rac1 in neuronal development, we have generated a conditional knock-out mouse, in which Rac1 is ablated in the whole brain. Rac1-deficient cerebellar granule neurons, which do not express other Rac isoforms, showed impaired neuronal migration and axon formation both in vivo...... and in vitro. In addition, Rac1 ablation disrupts lamellipodia formation in growth cones. The analysis of Rac1 effectors revealed the absence of the Wiskott-Aldrich syndrome protein (WASP) family verprolin-homologous protein (WAVE) complex from the plasma membrane of knock-out growth cones. Loss of WAVE...... function inhibited axon growth, whereas overexpression of a membrane-tethered WAVE mutant partially rescued axon growth in Rac1-knock-out neurons. In addition, pharmacological inhibition of the WAVE complex effector Arp2/3 also reduced axon growth. We propose that Rac1 recruits the WAVE complex...

  13. A deleterious Nav1.1 mutation selectively impairs telencephalic inhibitory neurons derived from Dravet Syndrome patients

    Science.gov (United States)

    Sun, Yishan; Paşca, Sergiu P; Portmann, Thomas; Goold, Carleton; Worringer, Kathleen A; Guan, Wendy; Chan, Karen C; Gai, Hui; Vogt, Daniel; Chen, Ying-Jiun J; Mao, Rong; Chan, Karrie; Rubenstein, John LR; Madison, Daniel V; Hallmayer, Joachim; Froehlich-Santino, Wendy M; Bernstein, Jonathan A; Dolmetsch, Ricardo E

    2016-01-01

    Dravet Syndrome is an intractable form of childhood epilepsy associated with deleterious mutations in SCN1A, the gene encoding neuronal sodium channel Nav1.1. Earlier studies using human induced pluripotent stem cells (iPSCs) have produced mixed results regarding the importance of Nav1.1 in human inhibitory versus excitatory neurons. We studied a Nav1.1 mutation (p.S1328P) identified in a pair of twins with Dravet Syndrome and generated iPSC-derived neurons from these patients. Characterization of the mutant channel revealed a decrease in current amplitude and hypersensitivity to steady-state inactivation. We then differentiated Dravet-Syndrome and control iPSCs into telencephalic excitatory neurons or medial ganglionic eminence (MGE)-like inhibitory neurons. Dravet inhibitory neurons showed deficits in sodium currents and action potential firing, which were rescued by a Nav1.1 transgene, whereas Dravet excitatory neurons were normal. Our study identifies biophysical impairments underlying a deleterious Nav1.1 mutation and supports the hypothesis that Dravet Syndrome arises from defective inhibitory neurons. DOI: http://dx.doi.org/10.7554/eLife.13073.001 PMID:27458797

  14. Temporal dynamics of glyoxalase 1 in secondary neuronal injury.

    Directory of Open Access Journals (Sweden)

    Philipp Pieroh

    Full Text Available BACKGROUND: Enhanced glycolysis leads to elevated levels of the toxic metabolite methylglyoxal which contributes to loss of protein-function, metabolic imbalance and cell death. Neurons were shown being highly susceptible to methylglyoxal toxicity. Glyoxalase 1 as an ubiquitous enzyme reflects the main detoxifying enzyme of methylglyoxal and underlies changes during aging and neurodegeneration. However, little is known about dynamics of Glyoxalase 1 following neuronal lesions so far. METHODS: To determine a possible involvement of Glyoxalase 1 in acute brain injury, we analysed the temporal dynamics of Glyoxalase 1 distribution and expression by immunohistochemistry and Western Blot analysis. Organotypic hippocampal slice cultures were excitotoxically (N-methyl-D-aspartate, 50 µM for 4 hours lesioned in vitro (5 minutes to 72 hours. Additionally, permanent middle cerebral artery occlusion was performed (75 minutes to 60 days. RESULTS: We found (i a predominant localisation of Glyoxalase 1 in endothelial cells in non-lesioned brains (ii a time-dependent up-regulation and re-distribution of Glyoxalase 1 in neurons and astrocytes and (iii a strong increase in Glyoxalase 1 dimers after neuronal injury (24 hours to 72 hours when compared to monomers of the protein. CONCLUSIONS: The high dynamics of Glyoxalase 1 expression and distribution following neuronal injury may indicate a novel role of Glyoxalase 1.

  15. The chemokine CXCL1/growth related oncogene increases sodium currents and neuronal excitability in small diameter sensory neurons

    Directory of Open Access Journals (Sweden)

    Wick Dayna M

    2008-09-01

    Full Text Available Abstract Background Altered Na+ channel expression, enhanced excitability, and spontaneous activity occur in nerve-injury and inflammatory models of pathological pain, through poorly understood mechanisms. The cytokine GRO/KC (growth related oncogene; CXCL1 shows strong, rapid upregulation in dorsal root ganglion in both nerve injury and inflammatory models. Neurons and glia express its receptor (CXCR2. CXCL1 has well-known effects on immune cells, but little is known about its direct effects on neurons. Results We report that GRO/KC incubation (1.5 nM, overnight caused marked upregulation of Na+ currents in acutely isolated small diameter rat (adult sensory neurons in vitro. In both IB4-positive and IB4-negative sensory neurons, TTX-resistant and TTX-sensitive currents increased 2- to 4 fold, without altered voltage dependence or kinetic changes. These effects required long exposures, and were completely blocked by co-incubation with protein synthesis inhibitor cycloheximide. Amplification of cDNA from the neuronal cultures showed that 3 Na channel isoforms were predominant both before and after GRO/KC treatment (Nav 1.1, 1.7, and 1.8. TTX-sensitive isoforms 1.1 and 1.7 significantly increased 2 – 3 fold after GRO/KC incubation, while 1.8 showed a trend towards increased expression. Current clamp experiments showed that GRO/KC caused a marked increase in excitability, including resting potential depolarization, decreased rheobase, and lower action potential threshold. Neurons acquired a striking ability to fire repetitively; IB4-positive cells also showed marked broadening of action potentials. Immunohistochemical labelling confirmed that the CXCR2 receptor was present in most neurons both in dissociated cells and in DRG sections, as previously shown for neurons in the CNS. Conclusion Many studies on the role of chemokines in pain conditions have focused on their rapid and indirect effects on neurons, via release of inflammatory mediators

  16. ASIC1A in neurons is critical for fear-related behaviors.

    Science.gov (United States)

    Taugher, R J; Lu, Y; Fan, R; Ghobbeh, A; Kreple, C J; Faraci, F M; Wemmie, J A

    2017-11-01

    Acid-sensing ion channels (ASICs) have been implicated in fear-, addiction- and depression-related behaviors in mice. While these effects have been attributed to ASIC1A in neurons, it has been reported that ASICs may also function in nonneuronal cells. To determine if ASIC1A in neurons is indeed required, we generated neuron-specific knockout (KO) mice with floxed Asic1a alleles disrupted by Cre recombinase driven by the neuron-specific synapsin I promoter (SynAsic1a KO mice). We confirmed that Cre expression occurred in neurons, but not all neurons, and not in nonneuronal cells including astrocytes. Consequent loss of ASIC1A in some but not all neurons was verified by western blotting, immunohistochemistry and electrophysiology. We found ASIC1A was disrupted in fear circuit neurons, and SynAsic1a KO mice exhibited prominent deficits in multiple fear-related behaviors including Pavlovian fear conditioning to cue and context, predator odor-evoked freezing and freezing responses to carbon dioxide inhalation. In contrast, in the nucleus accumbens ASIC1A expression was relatively normal in SynAsic1a KO mice, and consistent with this observation, cocaine conditioned place preference (CPP) was normal. Interestingly, depression-related behavior in the forced swim test, which has been previously linked to ASIC1A in the amygdala, was also normal. Together, these data suggest neurons are an important site of ASIC1A action in fear-related behaviors, whereas other behaviors likely depend on ASIC1A in other neurons or cell types not targeted in SynAsic1a KO mice. These findings highlight the need for further work to discern the roles of ASICs in specific cell types and brain sites. © 2017 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

  17. Identification of distinct telencephalic progenitor pools for neuronal diversity in the amygdala.

    Science.gov (United States)

    Hirata, Tsutomu; Li, Peijun; Lanuza, Guillermo M; Cocas, Laura A; Huntsman, Molly M; Corbin, Joshua G

    2009-02-01

    The development of the amygdala, a central structure of the limbic system, remains poorly understood. We found that two spatially distinct and early-specified telencephalic progenitor pools marked by the homeodomain transcription factor Dbx1 are major sources of neuronal cell diversity in the mature mouse amygdala. We found that Dbx1-positive cells of the ventral pallium generate the excitatory neurons of the basolateral complex and cortical amygdala nuclei. Moreover, Dbx1-derived cells comprise a previously unknown migratory stream that emanates from the preoptic area (POA), a ventral telencephalic domain adjacent to the diencephalic border. The Dbx1-positive, POA-derived population migrated specifically to the amygdala and, as defined by both immunochemical and electrophysiological criteria, generated a unique subclass of inhibitory neurons in the medial amygdala nucleus. Thus, this POA-derived population represents a previously unknown progenitor pool dedicated to the limbic system.

  18. Overexpression of survival motor neuron improves neuromuscular function and motor neuron survival in mutant SOD1 mice.

    Science.gov (United States)

    Turner, Bradley J; Alfazema, Neza; Sheean, Rebecca K; Sleigh, James N; Davies, Kay E; Horne, Malcolm K; Talbot, Kevin

    2014-04-01

    Spinal muscular atrophy results from diminished levels of survival motor neuron (SMN) protein in spinal motor neurons. Low levels of SMN also occur in models of amyotrophic lateral sclerosis (ALS) caused by mutant superoxide dismutase 1 (SOD1) and genetic reduction of SMN levels exacerbates the phenotype of transgenic SOD1(G93A) mice. Here, we demonstrate that SMN protein is significantly reduced in the spinal cords of patients with sporadic ALS. To test the potential of SMN as a modifier of ALS, we overexpressed SMN in 2 different strains of SOD1(G93A) mice. Neuronal overexpression of SMN significantly preserved locomotor function, rescued motor neurons, and attenuated astrogliosis in spinal cords of SOD1(G93A) mice. Despite this, survival was not prolonged, most likely resulting from SMN mislocalization and depletion of gems in motor neurons of symptomatic mice. Our results reveal that SMN upregulation slows locomotor deficit onset and motor neuron loss in this mouse model of ALS. However, disruption of SMN nuclear complexes by high levels of mutant SOD1, even in the presence of SMN overexpression, might limit its survival promoting effects in this specific mouse model. Studies in emerging mouse models of ALS are therefore warranted to further explore the potential of SMN as a modifier of ALS. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Netrin-1 Confines Rhombic Lip-Derived Neurons to the CNS

    Directory of Open Access Journals (Sweden)

    Andrea R. Yung

    2018-02-01

    Full Text Available During brainstem development, newborn neurons originating from the rhombic lip embark on exceptionally long migrations to generate nuclei important for audition, movement, and respiration. Along the way, this highly motile population passes several cranial nerves yet remains confined to the CNS. We found that Ntn1 accumulates beneath the pial surface separating the CNS from the PNS, with gaps at nerve entry sites. In mice null for Ntn1 or its receptor DCC, hindbrain neurons enter cranial nerves and migrate into the periphery. CNS neurons also escape when Ntn1 is selectively lost from the sub-pial region (SPR, and conversely, expression of Ntn1 throughout the mutant hindbrain can prevent their departure. These findings identify a permissive role for Ntn1 in maintaining the CNS-PNS boundary. We propose that Ntn1 confines rhombic lip-derived neurons by providing a preferred substrate for tangentially migrating neurons in the SPR, preventing their entry into nerve roots.

  20. Sensory experience regulates cortical inhibition by inducing IGF1 in VIP neurons.

    Science.gov (United States)

    Mardinly, A R; Spiegel, I; Patrizi, A; Centofante, E; Bazinet, J E; Tzeng, C P; Mandel-Brehm, C; Harmin, D A; Adesnik, H; Fagiolini, M; Greenberg, M E

    2016-03-17

    Inhibitory neurons regulate the adaptation of neural circuits to sensory experience, but the molecular mechanisms by which experience controls the connectivity between different types of inhibitory neuron to regulate cortical plasticity are largely unknown. Here we show that exposure of dark-housed mice to light induces a gene program in cortical vasoactive intestinal peptide (VIP)-expressing neurons that is markedly distinct from that induced in excitatory neurons and other subtypes of inhibitory neuron. We identify Igf1 as one of several activity-regulated genes that are specific to VIP neurons, and demonstrate that IGF1 functions cell-autonomously in VIP neurons to increase inhibitory synaptic input onto these neurons. Our findings further suggest that in cortical VIP neurons, experience-dependent gene transcription regulates visual acuity by activating the expression of IGF1, thus promoting the inhibition of disinhibitory neurons and affecting inhibition onto cortical pyramidal neurons.

  1. Optogenetic stimulation of locus ceruleus neurons augments inhibitory transmission to parasympathetic cardiac vagal neurons via activation of brainstem α1 and β1 receptors.

    Science.gov (United States)

    Wang, Xin; Piñol, Ramón A; Byrne, Peter; Mendelowitz, David

    2014-04-30

    Locus ceruleus (LC) noradrenergic neurons are critical in generating alertness. In addition to inducing cortical arousal, the LC also orchestrates changes in accompanying autonomic system function that compliments increased attention, such as during stress, excitation, and/or exposure to averse or novel stimuli. Although the association between arousal and increased heart rate is well accepted, the neurobiological link between the LC and parasympathetic neurons that control heart rate has not been identified. In this study, we test directly whether activation of noradrenergic neurons in the LC influences brainstem parasympathetic cardiac vagal neurons (CVNs). CVNs were identified in transgenic mice that express channel-rhodopsin-2 (ChR2) in LC tyrosine hydroxylase neurons. Photoactivation evoked a rapid depolarization, increased firing, and excitatory inward currents in ChR2-expressing neurons in the LC. Photostimulation of LC neurons did not alter excitatory currents, but increased inhibitory neurotransmission to CVNs. Optogenetic activation of LC neurons increased the frequency of isolated glycinergic IPSCs by 27 ± 8% (p = 0.003, n = 26) and augmented GABAergic IPSCs in CVNs by 21 ± 5% (p = 0.001, n = 26). Inhibiting α1, but not α2, receptors blocked the evoked responses. Inhibiting β1 receptors prevented the increase in glycinergic, but not GABAergic, IPSCs in CVNs. This study demonstrates LC noradrenergic neurons inhibit the brainstem CVNs that generate parasympathetic activity to the heart. This inhibition of CVNs would increase heart rate and risks associated with tachycardia. The receptors activated within this pathway, α1 and/or β1 receptors, are targets for clinically prescribed antagonists that promote slower, cardioprotective heart rates during heightened vigilant states.

  2. TRPA1 expression levels and excitability brake by KV channels influence cold sensitivity of TRPA1-expressing neurons.

    Science.gov (United States)

    Memon, Tosifa; Chase, Kevin; Leavitt, Lee S; Olivera, Baldomero M; Teichert, Russell W

    2017-06-14

    The molecular sensor of innocuous (painless) cold sensation is well-established to be transient receptor potential cation channel, subfamily M, member 8 (TRPM8). However, the role of transient receptor potential cation channel, subfamily A, member 1 (TRPA1) in noxious (painful) cold sensation has been controversial. We find that TRPA1 channels contribute to the noxious cold sensitivity of mouse somatosensory neurons, independent of TRPM8 channels, and that TRPA1-expressing neurons are largely non-overlapping with TRPM8-expressing neurons in mouse dorsal-root ganglia (DRG). However, relatively few TRPA1-expressing neurons (e.g., responsive to allyl isothiocyanate or AITC, a selective TRPA1 agonist) respond overtly to cold temperature in vitro, unlike TRPM8-expressing neurons, which almost all respond to cold. Using somatosensory neurons from TRPM8-/- mice and subtype-selective blockers of TRPM8 and TRPA1 channels, we demonstrate that responses to cold temperatures from TRPA1-expressing neurons are mediated by TRPA1 channels. We also identify two factors that affect the cold-sensitivity of TRPA1-expressing neurons: (1) cold-sensitive AITC-sensitive neurons express relatively more TRPA1 transcripts than cold-insensitive AITC-sensitive neurons and (2) voltage-gated potassium (K V ) channels attenuate the cold-sensitivity of some TRPA1-expressing neurons. The combination of these two factors, combined with the relatively weak agonist-like activity of cold temperature on TRPA1 channels, partially explains why few TRPA1-expressing neurons respond to cold. Blocking K V channels also reveals another subclass of noxious cold-sensitive DRG neurons that do not express TRPM8 or TRPA1 channels. Altogether, the results of this study provide novel insights into the cold-sensitivity of different subclasses of somatosensory neurons. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  3. Orthodenticle is required for the development of olfactory projection neurons and local interneurons in Drosophila

    Directory of Open Access Journals (Sweden)

    Sonia Sen

    2014-07-01

    Full Text Available The accurate wiring of nervous systems involves precise control over cellular processes like cell division, cell fate specification, and targeting of neurons. The nervous system of Drosophila melanogaster is an excellent model to understand these processes. Drosophila neurons are generated by stem cell like precursors called neuroblasts that are formed and specified in a highly stereotypical manner along the neuroectoderm. This stereotypy has been attributed, in part, to the expression and function of transcription factors that act as intrinsic cell fate determinants in the neuroblasts and their progeny during embryogenesis. Here we focus on the lateral neuroblast lineage, ALl1, of the antennal lobe and show that the transcription factor-encoding cephalic gap gene orthodenticle is required in this lineage during postembryonic brain development. We use immunolabelling to demonstrate that Otd is expressed in the neuroblast of this lineage during postembryonic larval stages. Subsequently, we use MARCM clonal mutational methods to show that the majority of the postembryonic neuronal progeny in the ALl1 lineage undergoes apoptosis in the absence of orthodenticle. Moreover, we demonstrate that the neurons that survive in the orthodenticle loss-of-function condition display severe targeting defects in both the proximal (dendritic and distal (axonal neurites. These findings indicate that the cephalic gap gene orthodenticle acts as an important intrinsic determinant in the ALl1 neuroblast lineage and, hence, could be a member of a putative combinatorial code involved in specifying the fate and identity of cells in this lineage.

  4. Control of nuclear material specified equipment and specified material

    International Nuclear Information System (INIS)

    1982-04-01

    The goal and application field of NE 2.02 regulatory guide of CNEN (Comissao Nacional de Energia Nuclear), are described. This regulatory guide is about nuclear material management, specified equipment and specified material. (E.G.) [pt

  5. Block of voltage-gated potassium channels by Pacific ciguatoxin-1 contributes to increased neuronal excitability in rat sensory neurons

    International Nuclear Information System (INIS)

    Birinyi-Strachan, Liesl C.; Gunning, Simon J.; Lewis, Richard J.; Nicholson, Graham M.

    2005-01-01

    The present study investigated the actions of the polyether marine toxin Pacific ciguatoxin-1 (P-CTX-1) on neuronal excitability in rat dorsal root ganglion (DRG) neurons using patch-clamp recording techniques. Under current-clamp conditions, bath application of 2-20 nM P-CTX-1 caused a rapid, concentration-dependent depolarization of the resting membrane potential in neurons expressing tetrodotoxin (TTX)-sensitive voltage-gated sodium (Na v ) channels. This action was completely suppressed by the addition of 200 nM TTX to the external solution, indicating that this effect was mediated through TTX-sensitive Na v channels. In addition, P-CTX-1 also prolonged action potential and afterhyperpolarization (AHP) duration. In a subpopulation of neurons, P-CTX-1 also produced tonic action potential firing, an effect that was not accompanied by significant oscillation of the resting membrane potential. Conversely, in neurons expressing TTX-resistant Na v currents, P-CTX-1 failed to alter any parameter of neuronal excitability examined in this study. Under voltage-clamp conditions in rat DRG neurons, P-CTX-1 inhibited both delayed-rectifier and 'A-type' potassium currents in a dose-dependent manner, actions that occurred in the absence of alterations to the voltage dependence of activation. These actions appear to underlie the prolongation of the action potential and AHP, and contribute to repetitive firing. These data indicate that a block of potassium channels contributes to the increase in neuronal excitability, associated with a modulation of Na v channel gating, observed clinically in response to ciguatera poisoning

  6. The splicing regulator PTBP1 controls the activity of the transcription factor Pbx1 during neuronal differentiation.

    Science.gov (United States)

    Linares, Anthony J; Lin, Chia-Ho; Damianov, Andrey; Adams, Katrina L; Novitch, Bennett G; Black, Douglas L

    2015-12-24

    The RNA-binding proteins PTBP1 and PTBP2 control programs of alternative splicing during neuronal development. PTBP2 was found to maintain embryonic splicing patterns of many synaptic and cytoskeletal proteins during differentiation of neuronal progenitor cells (NPCs) into early neurons. However, the role of the earlier PTBP1 program in embryonic stem cells (ESCs) and NPCs was not clear. We show that PTBP1 controls a program of neuronal gene expression that includes the transcription factor Pbx1. We identify exons specifically regulated by PTBP1 and not PTBP2 as mouse ESCs differentiate into NPCs. We find that PTBP1 represses Pbx1 exon 7 and the expression of the neuronal Pbx1a isoform in ESCs. Using CRISPR-Cas9 to delete regulatory elements for exon 7, we induce Pbx1a expression in ESCs, finding that this activates transcription of neuronal genes. Thus, PTBP1 controls the activity of Pbx1 to suppress its neuronal transcriptional program prior to induction of NPC development.

  7. Gemfibrozil, a lipid-lowering drug, upregulates interleukin-1 receptor antagonist in mouse cortical neurons: Implications for neuronal self-defense

    Science.gov (United States)

    Corbett, Grant T.; Roy, Avik; Pahan, Kalipada

    2012-01-01

    Chronic inflammation is becoming a hallmark of several neurodegenerative disorders and accordingly, interleukin-1 beta (IL-1β), a proinflammatory cytokine, is implicated in the pathogenesis of neurodegenerative diseases. While IL-1β binds to its high-affinity receptor, interleukin-1 receptor (IL-1R), and upregulates proinflammatory signaling pathways, interleukin-1 receptor antagonist (IL-1Ra) adheres to the same receptor and inhibits proinflammatory cell signaling. Therefore, upregulation of IL-1Ra is considered important in attenuating inflammation. The present study underlines a novel application of gemfibrozil, an FDA-approved lipid-lowering drug, in increasing the expression of IL-1Ra in primary mouse and human neurons. Gemfibrozil alone induced an early and pronounced increase in the expression of IL-1Ra in primary mouse cortical neurons. Activation of type IA p110α phosphatidylinositol 3-kinase (PI3-K) and Akt by gemfibrozil and abrogation of gemfibrozil-induced upregulation of IL-1Ra by inhibitors of PI3-K and Akt indicate a role of the PI3-K – Akt pathway in the upregulation of IL-1Ra. Gemfibrozil also induced the activation of cAMP response element-binding (CREB) via the PI3-K – Akt pathway and siRNA attenuation of CREB abolished the gemfibrozil-mediated increase in IL-1Ra. Furthermore, gemfibrozil was able to protect neurons from IL-1β insult. However, siRNA knockdown of neuronal IL-1Ra abrogated the protective effect of gemfibrozil against IL-1β suggesting that this drug increases the defense mechanism of cortical neurons via upregulation of IL-1Ra. Together, these results highlight the importance of the PI3-K – Akt – CREB pathway in mediating gemfibrozil-induced upregulation of IL-1Ra in neurons and suggest gemfibrozil as a possible therapeutic treatment for propagating neuronal self defense in neuroinflammatory and neurodegenerative disorders. PMID:22706077

  8. Neuronal Cx3cr1 Deficiency Protects against Amyloid β-Induced Neurotoxicity

    Science.gov (United States)

    Dworzak, Jenny; Renvoisé, Benoît; Habchi, Johnny; Yates, Emma V.; Combadière, Christophe; Knowles, Tuomas P.; Dobson, Christopher M.; Blackstone, Craig; Paulsen, Ole; Murphy, Philip M.

    2015-01-01

    Cx3cr1, the receptor for the chemokine Cx3cl1 (fractalkine), has been implicated in the progression and severity of Alzheimer’s disease-like pathology in mice, but the underlying mechanisms remain unclear. A complicating factor is that Cx3cr1 has been demonstrated in both neurons and microglia. Here, we have dissected the differences between neuronal and microglial Cx3cr1, specifically by comparing direct amyloid-β-induced toxicity in cultured, mature, microglia-depleted hippocampal neurons from wild-type and Cx3cr1-/- mice. Wild-type neurons expressed both Cx3cl1 and Cx3cr1 and released Cx3cl1 in response to amyloid-β. Knockout of neuronal Cx3cr1 abated amyloid-β-induced lactate dehydrogenase release. Furthermore, amyloid-β differentially induced depression of pre- and postsynaptic components of miniature excitatory postsynaptic currents, in a peptide conformation-dependent manner. Knockout of neuronal Cx3cr1 abated effects of both amyloid-β conformational states, which were differentiable by aggregation kinetics and peptide morphology. We obtained similar results after both acute and chronic treatment of cultured neurons with the Cx3cr1 antagonist F1. Thus, neuronal Cx3cr1 may impact Alzheimer’s disease-like pathology by modulating conformational state-dependent amyloid-β-induced synaptotoxicity. PMID:26038823

  9. Neuronal Cx3cr1 Deficiency Protects against Amyloid β-Induced Neurotoxicity.

    Directory of Open Access Journals (Sweden)

    Jenny Dworzak

    Full Text Available Cx3cr1, the receptor for the chemokine Cx3cl1 (fractalkine, has been implicated in the progression and severity of Alzheimer's disease-like pathology in mice, but the underlying mechanisms remain unclear. A complicating factor is that Cx3cr1 has been demonstrated in both neurons and microglia. Here, we have dissected the differences between neuronal and microglial Cx3cr1, specifically by comparing direct amyloid-β-induced toxicity in cultured, mature, microglia-depleted hippocampal neurons from wild-type and Cx3cr1-/- mice. Wild-type neurons expressed both Cx3cl1 and Cx3cr1 and released Cx3cl1 in response to amyloid-β. Knockout of neuronal Cx3cr1 abated amyloid-β-induced lactate dehydrogenase release. Furthermore, amyloid-β differentially induced depression of pre- and postsynaptic components of miniature excitatory postsynaptic currents, in a peptide conformation-dependent manner. Knockout of neuronal Cx3cr1 abated effects of both amyloid-β conformational states, which were differentiable by aggregation kinetics and peptide morphology. We obtained similar results after both acute and chronic treatment of cultured neurons with the Cx3cr1 antagonist F1. Thus, neuronal Cx3cr1 may impact Alzheimer's disease-like pathology by modulating conformational state-dependent amyloid-β-induced synaptotoxicity.

  10. CALHM1 deficiency impairs cerebral neuron activity and memory flexibility in mice.

    Science.gov (United States)

    Vingtdeux, Valérie; Chang, Eric H; Frattini, Stephen A; Zhao, Haitian; Chandakkar, Pallavi; Adrien, Leslie; Strohl, Joshua J; Gibson, Elizabeth L; Ohmoto, Makoto; Matsumoto, Ichiro; Huerta, Patricio T; Marambaud, Philippe

    2016-04-12

    CALHM1 is a cell surface calcium channel expressed in cerebral neurons. CALHM1 function in the brain remains unknown, but recent results showed that neuronal CALHM1 controls intracellular calcium signaling and cell excitability, two mechanisms required for synaptic function. Here, we describe the generation of Calhm1 knockout (Calhm1(-/-)) mice and investigate CALHM1 role in neuronal and cognitive functions. Structural analysis revealed that Calhm1(-/-) brains had normal regional and cellular architecture, and showed no evidence of neuronal or synaptic loss, indicating that CALHM1 deficiency does not affect brain development or brain integrity in adulthood. However, Calhm1(-/-) mice showed a severe impairment in memory flexibility, assessed in the Morris water maze, and a significant disruption of long-term potentiation without alteration of long-term depression, measured in ex vivo hippocampal slices. Importantly, in primary neurons and hippocampal slices, CALHM1 activation facilitated the phosphorylation of NMDA and AMPA receptors by protein kinase A. Furthermore, neuronal CALHM1 activation potentiated the effect of glutamate on the expression of c-Fos and C/EBPβ, two immediate-early gene markers of neuronal activity. Thus, CALHM1 controls synaptic activity in cerebral neurons and is required for the flexible processing of memory in mice. These results shed light on CALHM1 physiology in the mammalian brain.

  11. Kv2 Channel Regulation of Action Potential Repolarization and Firing Patterns in Superior Cervical Ganglion Neurons and Hippocampal CA1 Pyramidal Neurons

    Science.gov (United States)

    Liu, Pin W.

    2014-01-01

    Kv2 family “delayed-rectifier” potassium channels are widely expressed in mammalian neurons. Kv2 channels activate relatively slowly and their contribution to action potential repolarization under physiological conditions has been unclear. We explored the function of Kv2 channels using a Kv2-selective blocker, Guangxitoxin-1E (GxTX-1E). Using acutely isolated neurons, mixed voltage-clamp and current-clamp experiments were done at 37°C to study the physiological kinetics of channel gating and action potentials. In both rat superior cervical ganglion (SCG) neurons and mouse hippocampal CA1 pyramidal neurons, 100 nm GxTX-1E produced near-saturating block of a component of current typically constituting ∼60–80% of the total delayed-rectifier current. GxTX-1E also reduced A-type potassium current (IA), but much more weakly. In SCG neurons, 100 nm GxTX-1E broadened spikes and voltage clamp experiments using action potential waveforms showed that Kv2 channels carry ∼55% of the total outward current during action potential repolarization despite activating relatively late in the spike. In CA1 neurons, 100 nm GxTX-1E broadened spikes evoked from −70 mV, but not −80 mV, likely reflecting a greater role of Kv2 when other potassium channels were partially inactivated at −70 mV. In both CA1 and SCG neurons, inhibition of Kv2 channels produced dramatic depolarization of interspike voltages during repetitive firing. In CA1 neurons and some SCG neurons, this was associated with increased initial firing frequency. In all neurons, inhibition of Kv2 channels depressed maintained firing because neurons entered depolarization block more readily. Therefore, Kv2 channels can either decrease or increase neuronal excitability depending on the time scale of excitation. PMID:24695716

  12. Orexin-A increases the firing activity of hippocampal CA1 neurons through orexin-1 receptors.

    Science.gov (United States)

    Chen, Xin-Yi; Chen, Lei; Du, Yi-Feng

    2017-07-01

    Orexins including two peptides, orexin-A and orexin-B, are produced in the posterior lateral hypothalamus. Much evidence has indicated that central orexinergic systems play numerous functions including energy metabolism, feeding behavior, sleep/wakefulness, and neuroendocrine and sympathetic activation. Morphological studies have shown that the hippocampal CA1 regions receive orexinergic innervation originating from the hypothalamus. Positive orexin-1 (OX 1 ) receptors are detected in the CA1 regions. Previous behavioral studies have shown that microinjection of OX 1 receptor antagonist into the hippocampus impairs acquisition and consolidation of spatial memory. However, up to now, little has been known about the direct electrophysiological effects of orexin-A on hippocampal CA1 neurons. Employing multibarrel single-unit extracellular recordings, the present study showed that micropressure administration of orexin-A significantly increased the spontaneous firing rate from 2.96 ± 0.85 to 8.45 ± 1.86 Hz (P neurons in male rats. Furthermore, application of the specific OX 1 receptor antagonist SB-334867 alone significantly decreased the firing rate from 4.02 ± 1.08 to 2.11 ± 0.58 Hz in 7 out of the 17 neurons (P neurons. Coapplication of SB-334867 completely blocked orexin-A-induced excitation of hippocampal CA1 neurons. The PLC pathway may be involved in activation of OX 1 receptor-induced excitation of CA1 neurons. Taken together, the present study's results suggest that orexin-A produces excitatory effects on hippocampal neurons via OX 1 receptors. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  13. Abnormal development of monoaminergic neurons is implicated in mood fluctuations and bipolar disorder.

    Science.gov (United States)

    Jukic, Marin M; Carrillo-Roa, Tania; Bar, Michal; Becker, Gal; Jovanovic, Vukasin M; Zega, Ksenija; Binder, Elisabeth B; Brodski, Claude

    2015-03-01

    Subtle mood fluctuations are normal emotional experiences, whereas drastic mood swings can be a manifestation of bipolar disorder (BPD). Despite their importance for normal and pathological behavior, the mechanisms underlying endogenous mood instability are largely unknown. During embryogenesis, the transcription factor Otx2 orchestrates the genetic networks directing the specification of dopaminergic (DA) and serotonergic (5-HT) neurons. Here we behaviorally phenotyped mouse mutants overexpressing Otx2 in the hindbrain, resulting in an increased number of DA neurons and a decreased number of 5-HT neurons in both developing and mature animals. Over the course of 1 month, control animals exhibited stable locomotor activity in their home cages, whereas mutants showed extended periods of elevated or decreased activity relative to their individual average. Additional behavioral paradigms, testing for manic- and depressive-like behavior, demonstrated that mutants showed an increase in intra-individual fluctuations in locomotor activity, habituation, risk-taking behavioral parameters, social interaction, and hedonic-like behavior. Olanzapine, lithium, and carbamazepine ameliorated the behavioral alterations of the mutants, as did the mixed serotonin receptor agonist quipazine and the specific 5-HT2C receptor agonist CP-809101. Testing the relevance of the genetic networks specifying monoaminergic neurons for BPD in humans, we applied an interval-based enrichment analysis tool for genome-wide association studies. We observed that the genes specifying DA and 5-HT neurons exhibit a significant level of aggregated association with BPD but not with schizophrenia or major depressive disorder. The results of our translational study suggest that aberrant development of monoaminergic neurons leads to mood fluctuations and may be associated with BPD.

  14. Generation of Induced Neuronal Cells by the Single Reprogramming Factor ASCL1

    Directory of Open Access Journals (Sweden)

    Soham Chanda

    2014-08-01

    Full Text Available Direct conversion of nonneural cells to functional neurons holds great promise for neurological disease modeling and regenerative medicine. We previously reported rapid reprogramming of mouse embryonic fibroblasts (MEFs into mature induced neuronal (iN cells by forced expression of three transcription factors: ASCL1, MYT1L, and BRN2. Here, we show that ASCL1 alone is sufficient to generate functional iN cells from mouse and human fibroblasts and embryonic stem cells, indicating that ASCL1 is the key driver of iN cell reprogramming in different cell contexts and that the role of MYT1L and BRN2 is primarily to enhance the neuronal maturation process. ASCL1-induced single-factor neurons (1F-iN expressed mature neuronal markers, exhibited typical passive and active intrinsic membrane properties, and formed functional pre- and postsynaptic structures. Surprisingly, ASCL1-induced iN cells were predominantly excitatory, demonstrating that ASCL1 is permissive but alone not deterministic for the inhibitory neuronal lineage.

  15. CNF1 improves astrocytic ability to support neuronal growth and differentiation in vitro.

    Directory of Open Access Journals (Sweden)

    Fiorella Malchiodi-Albedi

    Full Text Available Modulation of cerebral Rho GTPases activity in mice brain by intracerebral administration of Cytotoxic Necrotizing Factor 1 (CNF1 leads to enhanced neurotransmission and synaptic plasticity and improves learning and memory. To gain more insight into the interactions between CNF1 and neuronal cells, we used primary neuronal and astrocytic cultures from rat embryonic brain to study CNF1 effects on neuronal differentiation, focusing on dendritic tree growth and synapse formation, which are strictly modulated by Rho GTPases. CNF1 profoundly remodeled the cytoskeleton of hippocampal and cortical neurons, which showed philopodia-like, actin-positive projections, thickened and poorly branched dendrites, and a decrease in synapse number. CNF1 removal, however, restored dendritic tree development and synapse formation, suggesting that the toxin can reversibly block neuronal differentiation. On differentiated neurons, CNF1 had a similar effacing effect on synapses. Therefore, a direct interaction with CNF1 is apparently deleterious for neurons. Since astrocytes play a pivotal role in neuronal differentiation and synaptic regulation, we wondered if the beneficial in vivo effect could be mediated by astrocytes. Primary astrocytes from embryonic cortex were treated with CNF1 for 48 hours and used as a substrate for growing hippocampal neurons. Such neurons showed an increased development of neurites, in respect to age-matched controls, with a wider dendritic tree and a richer content in synapses. In CNF1-exposed astrocytes, the production of interleukin 1β, known to reduce dendrite development and complexity in neuronal cultures, was decreased. These results demonstrate that astrocytes, under the influence of CNF1, increase their supporting activity on neuronal growth and differentiation, possibly related to the diminished levels of interleukin 1β. These observations suggest that the enhanced synaptic plasticity and improved learning and memory described

  16. CNF1 Improves Astrocytic Ability to Support Neuronal Growth and Differentiation In vitro

    Science.gov (United States)

    Malchiodi-Albedi, Fiorella; Paradisi, Silvia; Di Nottia, Michela; Simone, Daiana; Travaglione, Sara; Falzano, Loredana; Guidotti, Marco; Frank, Claudio; Cutarelli, Alessandro; Fabbri, Alessia; Fiorentini, Carla

    2012-01-01

    Modulation of cerebral Rho GTPases activity in mice brain by intracerebral administration of Cytotoxic Necrotizing Factor 1 (CNF1) leads to enhanced neurotransmission and synaptic plasticity and improves learning and memory. To gain more insight into the interactions between CNF1 and neuronal cells, we used primary neuronal and astrocytic cultures from rat embryonic brain to study CNF1 effects on neuronal differentiation, focusing on dendritic tree growth and synapse formation, which are strictly modulated by Rho GTPases. CNF1 profoundly remodeled the cytoskeleton of hippocampal and cortical neurons, which showed philopodia-like, actin-positive projections, thickened and poorly branched dendrites, and a decrease in synapse number. CNF1 removal, however, restored dendritic tree development and synapse formation, suggesting that the toxin can reversibly block neuronal differentiation. On differentiated neurons, CNF1 had a similar effacing effect on synapses. Therefore, a direct interaction with CNF1 is apparently deleterious for neurons. Since astrocytes play a pivotal role in neuronal differentiation and synaptic regulation, we wondered if the beneficial in vivo effect could be mediated by astrocytes. Primary astrocytes from embryonic cortex were treated with CNF1 for 48 hours and used as a substrate for growing hippocampal neurons. Such neurons showed an increased development of neurites, in respect to age-matched controls, with a wider dendritic tree and a richer content in synapses. In CNF1-exposed astrocytes, the production of interleukin 1β, known to reduce dendrite development and complexity in neuronal cultures, was decreased. These results demonstrate that astrocytes, under the influence of CNF1, increase their supporting activity on neuronal growth and differentiation, possibly related to the diminished levels of interleukin 1β. These observations suggest that the enhanced synaptic plasticity and improved learning and memory described in CNF1-injected

  17. The brain-specific factor FEZ1 is a determinant of neuronal susceptibility to HIV-1 infection.

    LENUS (Irish Health Repository)

    Haedicke, Juliane

    2009-08-18

    Neurons are one of the few cell types in the human body that do not support HIV type-1 (HIV-1) replication. Although the lack of key receptors is a major obstacle to infection, studies suggest that additional functions inhibit virus replication to explain the exquisite resistance of neurons to HIV-1. However, specific neuronal factors that may explain this resistance remain to be discovered. In a screen for antiviral factors using a fibroblast line chemically mutagenized and selected for resistance to retroviral infection, we recently identified induction of rat FEZ1 (fasciculation and elongation protein zeta-1), a brain-specific protein, as the cause of this resistance. When exogenously expressed in nonneuronal cell lines rat FEZ1 blocked nuclear entry of retroviral DNA. Here, we demonstrate that among human brain cells, neurons naturally express high levels of FEZ1 compared to astrocytes or microglia cells and are correspondingly less susceptible to infection with pseudotyped HIV-1 that bypasses receptor-mediated viral entry. Demonstrating that endogenous FEZ1 was functionally important in the resistance of neurons to HIV-1 infection, siRNA-mediated knockdown of endogenous FEZ1 increased the infectivity of neurons while sensitive brain cell types like microglia became more resistant upon FEZ1 overexpression. In addition, FEZ1 expression was not induced in response to IFN treatment. As such, in contrast to other widely expressed, IFN-inducible antiviral factors, FEZ1 appears to represent a unique neuron-specific determinant of cellular susceptibility to infection in a cell type that is naturally resistant to HIV-1.

  18. A small population of hypothalamic neurons govern fertility: the critical role of VAX1 in GnRH neuron development and fertility maintenance.

    Science.gov (United States)

    Hoffmann, Hanne M; Mellon, Pamela L

    2016-01-01

    Fertility depends on the correct maturation and function of approximately 800 gonadotropin-releasing hormone (GnRH) neurons in the brain. GnRH neurons are at the apex of the hypothalamic-pituitary-gonadal axis that regulates fertility. In adulthood, GnRH neurons are scattered throughout the anterior hypothalamic area and project to the median eminence, where GnRH is released into the portal vasculature to stimulate release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary. LH and FSH then regulate gonadal steroidogenesis and gametogenesis. Absence of GnRH neurons or inappropriate GnRH release leads to infertility. Despite the critical role of GnRH neurons in fertility, we still have a limited understanding of the genes responsible for proper GnRH neuron development and function in adulthood. GnRH neurons originate in the olfactory placode then migrate into the brain. Homeodomain transcription factors expressed within GnRH neurons or along their migratory path are candidate genes for inherited infertility. Using a combined in vitro and in vivo approach, we have identified Ventral Anterior Homeobox 1 ( Vax1 ) as a novel homeodomain transcription factor responsible for GnRH neuron maturation and fertility. GnRH neuron counts in Vax1 knock-out embryos revealed Vax1 to be required for the presence of GnRH-expressing cells at embryonic day 17.5 (E17.5), but not at E13.5. To localize the effects of Vax1 on fertility, we generated Vax1 flox mice and crossed them with Gnrh cre mice to specifically delete Vax1 within GnRH neurons. GnRH staining in Vax1 flox/flox :GnRH cre mice show a total absence of GnRH expression in the adult. We performed lineage tracing in Vax1 flox/flox :GnRH cre :RosaLacZ mice which proved GnRH neurons to be alive, but incapable of expressing GnRH. The absence of GnRH leads to delayed puberty, hypogonadism and complete infertility in both sexes. Finally, using the immortalized model GnRH neuron cell lines, GN11 and

  19. Regulatory Mechanisms Controlling Maturation of Serotonin Neuron Identity and Function.

    Science.gov (United States)

    Spencer, William C; Deneris, Evan S

    2017-01-01

    The brain serotonin (5-hydroxytryptamine; 5-HT) system has been extensively studied for its role in normal physiology and behavior, as well as, neuropsychiatric disorders. The broad influence of 5-HT on brain function, is in part due to the vast connectivity pattern of 5-HT-producing neurons throughout the CNS. 5-HT neurons are born and terminally specified midway through embryogenesis, then enter a protracted period of maturation, where they functionally integrate into CNS circuitry and then are maintained throughout life. The transcriptional regulatory networks controlling progenitor cell generation and terminal specification of 5-HT neurons are relatively well-understood, yet the factors controlling 5-HT neuron maturation are only recently coming to light. In this review, we first provide an update on the regulatory network controlling 5-HT neuron development, then delve deeper into the properties and regulatory strategies governing 5-HT neuron maturation. In particular, we discuss the role of the 5-HT neuron terminal selector transcription factor (TF) Pet-1 as a key regulator of 5-HT neuron maturation. Pet-1 was originally shown to positively regulate genes needed for 5-HT synthesis, reuptake and vesicular transport, hence 5-HT neuron-type transmitter identity. It has now been shown to regulate, both positively and negatively, many other categories of genes in 5-HT neurons including ion channels, GPCRs, transporters, neuropeptides, and other transcription factors. Its function as a terminal selector results in the maturation of 5-HT neuron excitability, firing characteristics, and synaptic modulation by several neurotransmitters. Furthermore, there is a temporal requirement for Pet-1 in the control of postmitotic gene expression trajectories thus indicating a direct role in 5-HT neuron maturation. Proper regulation of the maturation of cellular identity is critical for normal neuronal functioning and perturbations in the gene regulatory networks controlling

  20. Interferon-γ increases neuronal death in response to amyloid-β1-42

    Directory of Open Access Journals (Sweden)

    Williams Alun

    2006-03-01

    Full Text Available Abstract Background Alzheimer's disease is a neurodegenerative disorder characterized by a progressive cognitive impairment, the consequence of neuronal dysfunction and ultimately the death of neurons. The amyloid hypothesis proposes that neuronal damage results from the accumulation of insoluble, hydrophobic, fibrillar peptides such as amyloid-β1-42. These peptides activate enzymes resulting in a cascade of second messengers including prostaglandins and platelet-activating factor. Apoptosis of neurons is thought to follow as a consequence of the uncontrolled release of second messengers. Biochemical, histopathological and genetic studies suggest that pro-inflammatory cytokines play a role in neurodegeneration during Alzheimer's disease. In the current study we examined the effects of interferon (IFN-γ, tumour necrosis factor (TNFα, interleukin (IL-1β and IL-6 on neurons. Methods Primary murine cortical or cerebellar neurons, or human SH-SY5Y neuroblastoma cells, were grown in vitro. Neurons were treated with cytokines prior to incubation with different neuronal insults. Cell survival, caspase-3 activity (a measure of apoptosis and prostaglandin production were measured. Immunoblots were used to determine the effects of cytokines on the levels of cytoplasmic phospholipase A2 or phospholipase C γ-1. Results While none of the cytokines tested were directly neurotoxic, pre-treatment with IFN-γ sensitised neurons to the toxic effects of amyloid-β1-42 or HuPrP82-146 (a neurotoxic peptide found in prion diseases. The effects of IFN-γ were seen on cortical and cerebellar neurons, and on SH-SY5Y neuroblastoma cells. However, pre-treatment with IFN-γ did not affect the sensitivity to neurons treated with staurosporine or hydrogen peroxide. Pre-treatment with IFN-γ increased the levels of cytoplasmic phospholipase A2 in SH-SY5Y cells and increased prostaglandin E2 production in response to amyloid-β1-42. Conclusion Treatment of neuronal cells

  1. Neuronal sFlt1 and Vegfaa determine venous sprouting and spinal cord vascularization

    DEFF Research Database (Denmark)

    Wild, Raphael; Klems, Alina; Takamiya, Masanari

    2017-01-01

    Formation of organ-specific vasculatures requires cross-talk between developing tissue and specialized endothelial cells. Here we show how developing zebrafish spinal cord neurons coordinate vessel growth through balancing of neuron-derived Vegfaa, with neuronal sFlt1 restricting Vegfaa......-Kdrl mediated angiogenesis at the neurovascular interface. Neuron-specific loss of flt1 or increased neuronal vegfaa expression promotes angiogenesis and peri-neural tube vascular network formation. Combining loss of neuronal flt1 with gain of vegfaa promotes sprout invasion into the neural tube. On loss...... of neuronal flt1, ectopic sprouts emanate from veins involving special angiogenic cell behaviours including nuclear positioning and a molecular signature distinct from primary arterial or secondary venous sprouting. Manipulation of arteriovenous identity or Notch signalling established that ectopic sprouting...

  2. Molecular marker differences relate to developmental position and subsets of mesodiencephalic dopaminergic neurons.

    Directory of Open Access Journals (Sweden)

    Simone M Smits

    Full Text Available The development of mesodiencephalic dopaminergic (mdDA neurons located in the substantia nigra compacta (SNc and ventral tegmental area (VTA follow a number of stages marked by distinct events. After preparation of the region by signals that provide induction and patterning, several transcription factors have been identified, which are involved in specifying the neuronal fate of these cells. The specific vulnerability of SNc neurons is thought to root in these specific developmental programs. The present study examines the positions of young postmitotic mdDA neurons to relate developmental position to mdDA subset specific markers. MdDA neurons were mapped relative to the neuromeric domains (prosomeres 1-3 (P1-3, midbrain, and hindbrain as well as the longitudinal subdivisions (floor plate, basal plate, alar plate, as proposed by the prosomeric model. We found that postmitotic mdDA neurons are located mainly in the floorplate domain and very few in slightly more lateral domains. Moreover, mdDA neurons are present along a large proportion of the anterior/posterior axis extending from the midbrain to P3 in the diencephalon. The specific positions relate to some extent to the presence of specific subset markers as Ahd2. In the adult stage more of such subsets specific expressed genes are present and may represent a molecular map defining molecularly distinct groups of mdDA neurons.

  3. The sex of specific neurons controls female body growth in Drosophila.

    Science.gov (United States)

    Sawala, Annick; Gould, Alex P

    2017-10-01

    Sexual dimorphisms in body size are widespread throughout the animal kingdom but their underlying mechanisms are not well characterized. Most models for how sex chromosome genes specify size dimorphism have emphasized the importance of gonadal hormones and cell-autonomous influences in mammals versus strictly cell-autonomous mechanisms in Drosophila melanogaster. Here, we use tissue-specific genetics to investigate how sexual size dimorphism (SSD) is established in Drosophila. We find that the larger body size characteristic of Drosophila females is established very early in larval development via an increase in the growth rate per unit of body mass. We demonstrate that the female sex determination gene, Sex-lethal (Sxl), functions in central nervous system (CNS) neurons as part of a relay that specifies the early sex-specific growth trajectories of larval but not imaginal tissues. Neuronal Sxl acts additively in 2 neuronal subpopulations, one of which corresponds to 7 median neurosecretory cells: the insulin-producing cells (IPCs). Surprisingly, however, male-female differences in the production of insulin-like peptides (Ilps) from the IPCs do not appear to be involved in establishing SSD in early larvae, although they may play a later role. These findings support a relay model in which Sxl in neurons and Sxl in local tissues act together to specify the female-specific growth of the larval body. They also reveal that, even though the sex determination pathways in Drosophila and mammals are different, they both modulate body growth via a combination of tissue-autonomous and nonautonomous inputs.

  4. Neuronal calcium-binding proteins 1/2 localize to dorsal root ganglia and excitatory spinal neurons and are regulated by nerve injury

    DEFF Research Database (Denmark)

    Zhang, Ming Dong; Tortoriello, Giuseppe; Hsueh, Brian

    2014-01-01

    , and nerve injury-induced regulation of NECAB1/NECAB2 in mouse dorsal root ganglia (DRGs) and spinal cord. In DRGs, NECAB1/2 are expressed in around 70% of mainly small- and medium-sized neurons. Many colocalize with calcitonin gene-related peptide and isolectin B4, and thus represent nociceptors. NECAB1....../2 neurons are much more abundant in DRGs than the Ca2+-binding proteins (parvalbumin, calbindin, calretinin, and secretagogin) studied to date. In the spinal cord, the NECAB1/2 distribution is mainly complementary. NECAB1 labels interneurons and a plexus of processes in superficial layers of the dorsal horn....... In the dorsal horn, most NECAB1/2 neurons are glutamatergic. Both NECAB1/2 are transported into dorsal roots and peripheral nerves. Peripheral nerve injury reduces NECAB2, but not NECAB1, expression in DRG neurons. Our study identifies NECAB1/2 as abundant Ca2+-binding proteins in pain-related DRG neurons...

  5. Running rescues defective adult neurogenesis by shortening the length of the cell cycle of neural stem and progenitor cells.

    Science.gov (United States)

    Farioli-Vecchioli, Stefano; Mattera, Andrea; Micheli, Laura; Ceccarelli, Manuela; Leonardi, Luca; Saraulli, Daniele; Costanzi, Marco; Cestari, Vincenzo; Rouault, Jean-Pierre; Tirone, Felice

    2014-07-01

    Physical exercise increases the generation of new neurons in adult neurogenesis. However, only few studies have investigated the beneficial effects of physical exercise in paradigms of impaired neurogenesis. Here, we demonstrate that running fully reverses the deficient adult neurogenesis within the hippocampus and subventricular zone of the lateral ventricle, observed in mice lacking the antiproliferative gene Btg1. We also evaluated for the first time how running influences the cell cycle kinetics of stem and precursor subpopulations of wild-type and Btg1-null mice, using a new method to determine the cell cycle length. Our data show that in wild-type mice running leads to a cell cycle shortening only of NeuroD1-positive progenitor cells. In contrast, in Btg1-null mice, physical exercise fully reactivates the defective hippocampal neurogenesis, by shortening the S-phase length and the overall cell cycle duration of both neural stem (glial fibrillary acidic protein(+) and Sox2(+)) and progenitor (NeuroD1(+)) cells. These events are sufficient and necessary to reactivate the hyperproliferation observed in Btg1-null early-postnatal mice and to expand the pool of adult neural stem and progenitor cells. Such a sustained increase of cell proliferation in Btg1-null mice after running provides a long-lasting increment of proliferation, differentiation, and production of newborn neurons, which rescues the impaired pattern separation previously identified in Btg1-null mice. This study shows that running positively affects the cell cycle kinetics of specific subpopulations of newly generated neurons and suggests that the plasticity of neural stem cells without cell cycle inhibitory control is reactivated by running, with implications for the long-term modulation of neurogenesis. © 2014 AlphaMed Press.

  6. Cav1.3 channels control D2-autoreceptor responses via NCS-1 in substantia nigra dopamine neurons

    Science.gov (United States)

    Dragicevic, Elena; Poetschke, Christina; Duda, Johanna; Schlaudraff, Falk; Lammel, Stephan; Schiemann, Julia; Fauler, Michael; Hetzel, Andrea; Watanabe, Masahiko; Lujan, Rafael; Malenka, Robert C.; Striessnig, Joerg

    2014-01-01

    Dopamine midbrain neurons within the substantia nigra are particularly prone to degeneration in Parkinson’s disease. Their selective loss causes the major motor symptoms of Parkinson’s disease, but the causes for the high vulnerability of SN DA neurons, compared to neighbouring, more resistant ventral tegmental area dopamine neurons, are still unclear. Consequently, there is still no cure available for Parkinson’s disease. Current therapies compensate the progressive loss of dopamine by administering its precursor l-DOPA and/or dopamine D2-receptor agonists. D2-autoreceptors and Cav1.3-containing L-type Ca2+ channels both contribute to Parkinson’s disease pathology. L-type Ca2+ channel blockers protect SN DA neurons from degeneration in Parkinson’s disease and its mouse models, and they are in clinical trials for neuroprotective Parkinson’s disease therapy. However, their physiological functions in SN DA neurons remain unclear. D2-autoreceptors tune firing rates and dopamine release of SN DA neurons in a negative feedback loop through activation of G-protein coupled potassium channels (GIRK2, or KCNJ6). Mature SN DA neurons display prominent, non-desensitizing somatodendritic D2-autoreceptor responses that show pronounced desensitization in PARK-gene Parkinson’s disease mouse models. We analysed surviving human SN DA neurons from patients with Parkinson’s disease and from controls, and detected elevated messenger RNA levels of D2-autoreceptors and GIRK2 in Parkinson’s disease. By electrophysiological analysis of postnatal juvenile and adult mouse SN DA neurons in in vitro brain-slices, we observed that D2-autoreceptor desensitization is reduced with postnatal maturation. Furthermore, a transient high-dopamine state in vivo, caused by one injection of either l-DOPA or cocaine, induced adult-like, non-desensitizing D2-autoreceptor responses, selectively in juvenile SN DA neurons, but not ventral tegmental area dopamine neurons. With pharmacological

  7. Grin1 receptor deletion within CRF neurons enhances fear memory.

    Directory of Open Access Journals (Sweden)

    Georgette Gafford

    Full Text Available Corticotropin releasing factor (CRF dysregulation is implicated in mood and anxiety disorders such as posttraumatic stress disorder (PTSD. CRF is expressed in areas engaged in fear and anxiety processing including the central amygdala (CeA. Complicating our ability to study the contribution of CRF-containing neurons to fear and anxiety behavior is the wide variety of cell types in which CRF is expressed. To manipulate specific subpopulations of CRF containing neurons, our lab has developed a mouse with a Cre recombinase gene driven by a CRF promoter (CRFp3.0Cre (Martin et al., 2010. In these studies, mice that have the gene that encodes NR1 (Grin1 flanked by loxP sites (floxed were crossed with our previously developed CRFp3.0Cre mouse to selectively disrupt Grin1 within CRF containing neurons (Cre+/fGrin1+. We find that disruption of Grin1 in CRF neurons did not affect baseline levels of anxiety, locomotion, pain sensitivity or exploration of a novel object. However, baseline expression of Grin1 was decreased in Cre+/fGrin1+ mice as measured by RTPCR. Cre+/fGrin1+ mice showed enhanced auditory fear acquisition and retention without showing any significant effect on fear extinction. We measured Gria1, the gene that encodes AMPAR1 and the CREB activator Creb1 in the amygdala of Cre+/fGrin1+ mice after fear conditioning. Both Gria1 and Creb1 were enhanced in the amygdala after training. To determine if the Grin1-expressing CRF neurons within the CeA are responsible for the enhancement of fear memory in adults, we infused a lentivirus with Cre driven by a CRF promoter (LV pCRF-Cre/fGrin1+ into the CeA of floxed Grin1 mice. Cre driven deletion of Grin1 specifically within CRF expressing cells in the CeA also resulted in enhanced fear memory acquisition and retention. Altogether, these findings suggest that selective disruption of Grin1 within CeA CRF neurons strongly enhances fear memory.

  8. Development of raphe serotonin neurons from specification to guidance.

    Science.gov (United States)

    Kiyasova, Vera; Gaspar, Patricia

    2011-11-01

    The main features of the development of the serotonin (5-HT) raphe neurons have been known for many years but more recent molecular studies, using mouse genetics, have since unveiled several intriguing aspects of the specification of the raphe serotonergic system. These studies indicated that, although all 5-HT neurons in the raphe follow the same general program for their specification, there are also clear regional differences in the way that these neurons are specified and are guided towards different brain targets. Here we overview recent progress made in the understanding of the developmental programming of serotonergic neurons in the mouse raphe, emphasizing data showing how heterogeneous subsets of 5-HT neurons may be generated. Serotonergic progenitors are produced in the brainstem in different rhombomeres under the influence of a set of secreted factors, sonic hedgehog and fibroblast growth factors, which determine their position in the neural tube. Two main transcriptional gene networks are involved in the specification of 5-HT identity, with Lmx1b and Pet1 transcription factors as main players. A differential requirement for Pet1 was, however, revealed, which underlies an anatomical and functional diversity. Transcriptional programs controlling 5-HT identity could also impact axon guidance mechanisms directing 5-HT neurons to their targets. Although no direct links have yet been established, a large set of molecular determinants have already been shown to be involved in the growth, axon guidance and targeting of 5-HT raphe neurons, particularly within the forebrain. Alterations in the molecular mechanisms involved in 5-HT development are likely to have significant roles in mood disease predisposition. © 2011 The Authors. European Journal of Neuroscience © 2011 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

  9. 50 CFR 216.211 - Specified activity and specified geographical region.

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    2010-10-01

    ... OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE MAMMALS Taking of Marine Mammals Incidental to Explosive Severance.... Gulf of Mexico § 216.211 Specified activity and specified geographical region. (a) Regulations in this...

  10. 50 CFR 216.250 - Specified activity and specified geographical region.

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    2010-10-01

    ... OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE MARINE MAMMALS REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE MAMMALS Taking Marine Mammals Incidental to Conducting Precision Strike Weapon Missions in the Gulf of Mexico § 216.250 Specified activity and specified geographical region. (a...

  11. Neuronal SIRT1 (Silent Information Regulator 2 Homologue 1) Regulates Glycolysis and Mediates Resveratrol-Induced Ischemic Tolerance.

    Science.gov (United States)

    Koronowski, Kevin B; Khoury, Nathalie; Saul, Isabel; Loris, Zachary B; Cohan, Charles H; Stradecki-Cohan, Holly M; Dave, Kunjan R; Young, Juan I; Perez-Pinzon, Miguel A

    2017-11-01

    Resveratrol, at least in part via SIRT1 (silent information regulator 2 homologue 1) activation, protects against cerebral ischemia when administered 2 days before injury. However, it remains unclear if SIRT1 activation must occur, and in which brain cell types, for the induction of neuroprotection. We hypothesized that neuronal SIRT1 is essential for resveratrol-induced ischemic tolerance and sought to characterize the metabolic pathways regulated by neuronal Sirt1 at the cellular level in the brain. We assessed infarct size and functional outcome after transient 60 minute middle cerebral artery occlusion in control and inducible, neuronal-specific SIRT1 knockout mice. Nontargeted primary metabolomics analysis identified putative SIRT1-regulated pathways in brain. Glycolytic function was evaluated in acute brain slices from adult mice and primary neuronal-enriched cultures under ischemic penumbra-like conditions. Resveratrol-induced neuroprotection from stroke was lost in neuronal Sirt1 knockout mice. Metabolomics analysis revealed alterations in glucose metabolism on deletion of neuronal Sirt1 , accompanied by transcriptional changes in glucose metabolism machinery. Furthermore, glycolytic ATP production was impaired in acute brain slices from neuronal Sirt1 knockout mice. Conversely, resveratrol increased glycolytic rate in a SIRT1-dependent manner and under ischemic penumbra-like conditions in vitro. Our data demonstrate that resveratrol requires neuronal SIRT1 to elicit ischemic tolerance and identify a novel role for SIRT1 in the regulation of glycolytic function in brain. Identification of robust neuroprotective mechanisms that underlie ischemia tolerance and the metabolic adaptations mediated by SIRT1 in brain are crucial for the translation of therapies in cerebral ischemia and other neurological disorders. © 2017 American Heart Association, Inc.

  12. From Neurons to Newtons

    DEFF Research Database (Denmark)

    Nielsen, Bjørn Gilbert

    2001-01-01

    proteins generate forces, to the macroscopic levels where overt arm movements are vol- untarily controlled within an unpredictable environment by legions of neurons¯ring in orderly fashion. An extensive computer simulation system has been developed for this thesis, which at present contains a neural...... network scripting language for specifying arbitrary neural architectures, de¯nition ¯les for detailed spinal networks, various biologically realistic models of neurons, and dynamic synapses. Also included are structurally accurate models of intrafusal and extra-fusal muscle ¯bers and a general body...... that an explicit function may be derived which expresses the force that the spindle contractile elements must produce to exactly counter spindle unloading during muscle shortening. This information was used to calculate the corresponding "optimal" °-motoneuronal activity level. For some simple arm movement tasks...

  13. Nuclear depletion of apurinic/apyrimidinic endonuclease 1 (Ape1/Ref-1) is an indicator of energy disruption in neurons.

    Science.gov (United States)

    Singh, Shilpee; Englander, Ella W

    2012-11-01

    Apurinic/apyrimidinic endonuclease 1 (Ape1/Ref-1) is a multifunctional protein critical for cellular survival. Its involvement in adaptive survival responses includes key roles in redox sensing, transcriptional regulation, and repair of DNA damage via the base excision repair (BER) pathway. Ape1 is abundant in most cell types and central in integrating the first BER step catalyzed by different DNA glycosylases. BER is the main process for removal of oxidative DNA lesions in postmitotic brain cells, and after ischemic brain injury preservation of Ape1 coincides with neuronal survival, while its loss has been associated with neuronal death. Here, we report that in cultured primary neurons, diminution of cellular ATP by either oligomycin or H(2)O(2) is accompanied by depletion of nuclear Ape1, while other BER proteins are unaffected and retain their nuclear localization under these conditions. Importantly, while H(2)O(2) induces γH2AX phosphorylation, indicative of chromatin rearrangements in response to DNA damage, oligomycin does not. Furthermore, despite comparable diminution of ATP content, H(2)O(2) and oligomycin differentially affect critical parameters of mitochondrial respiration that ultimately determine cellular ATP content. Taken together, our findings demonstrate that in neurons, nuclear compartmentalization of Ape1 depends on ATP and loss of nuclear Ape1 reflects disruption of neuronal energy homeostasis. Energy crisis is a hallmark of stroke and other ischemic/hypoxic brain injuries. In vivo studies have shown that Ape1 deficit precedes neuronal loss in injured brain regions. Thus, our findings bring to light the possibility that energy failure-induced Ape1 depletion triggers neuronal death in ischemic brain injuries. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. CDKL5 and Shootin1 Interact and Concur in Regulating Neuronal Polarization.

    Directory of Open Access Journals (Sweden)

    Mohammad Sarfaraz Nawaz

    Full Text Available In the last years, the X-linked cyclin-dependent kinase-like 5 (CDKL5 gene has been associated with epileptic encephalopathies characterized by the early onset of intractable epilepsy, severe developmental delay, autistic features, and often the development of Rett syndrome-like features. Still, the role of CDKL5 in neuronal functions is not fully understood. By way of a yeast two hybrid screening we identified the interaction of CDKL5 with shootin1, a brain specific protein acting as a determinant of axon formation during neuronal polarization. We found evidence that CDKL5 is involved, at least in part, in regulating neuronal polarization through its interaction with shootin1. Indeed, the two proteins interact in vivo and both are localized in the distal tip of outgrowing axons. By using primary hippocampal neurons as model system we find that adequate CDKL5 levels are required for axon specification. In fact, a significant number of neurons overexpressing CDKL5 is characterized by supernumerary axons, while the silencing of CDKL5 disrupts neuronal polarization. Interestingly, shootin1 phosphorylation is reduced in neurons silenced for CDKL5 suggesting that the kinase affects, directly or indirectly, the post-translational modification of shootin1. Finally, we find that the capacity of CDKL5 to generate surplus axons is attenuated in neurons with reduced shootin1 levels, in agreement with the notion that two proteins act in a common pathway. Altogether, these results point to a role of CDKL5 in the early steps of neuronal differentiation that can be explained, at least in part, by its association with shootin1.

  15. CDKL5 and Shootin1 Interact and Concur in Regulating Neuronal Polarization.

    Science.gov (United States)

    Nawaz, Mohammad Sarfaraz; Giarda, Elisa; Bedogni, Francesco; La Montanara, Paolo; Ricciardi, Sara; Ciceri, Dalila; Alberio, Tiziana; Landsberger, Nicoletta; Rusconi, Laura; Kilstrup-Nielsen, Charlotte

    2016-01-01

    In the last years, the X-linked cyclin-dependent kinase-like 5 (CDKL5) gene has been associated with epileptic encephalopathies characterized by the early onset of intractable epilepsy, severe developmental delay, autistic features, and often the development of Rett syndrome-like features. Still, the role of CDKL5 in neuronal functions is not fully understood. By way of a yeast two hybrid screening we identified the interaction of CDKL5 with shootin1, a brain specific protein acting as a determinant of axon formation during neuronal polarization. We found evidence that CDKL5 is involved, at least in part, in regulating neuronal polarization through its interaction with shootin1. Indeed, the two proteins interact in vivo and both are localized in the distal tip of outgrowing axons. By using primary hippocampal neurons as model system we find that adequate CDKL5 levels are required for axon specification. In fact, a significant number of neurons overexpressing CDKL5 is characterized by supernumerary axons, while the silencing of CDKL5 disrupts neuronal polarization. Interestingly, shootin1 phosphorylation is reduced in neurons silenced for CDKL5 suggesting that the kinase affects, directly or indirectly, the post-translational modification of shootin1. Finally, we find that the capacity of CDKL5 to generate surplus axons is attenuated in neurons with reduced shootin1 levels, in agreement with the notion that two proteins act in a common pathway. Altogether, these results point to a role of CDKL5 in the early steps of neuronal differentiation that can be explained, at least in part, by its association with shootin1.

  16. Regulation of neuronal APL-1 expression by cholesterol starvation.

    Directory of Open Access Journals (Sweden)

    Mary Wiese

    Full Text Available BACKGROUND: Alzheimer's disease (AD is a neurodegenerative disorder characterized by the deposition of β-amyloid plaques composed primarily of the amyloid-β peptide, a cleavage product of amyloid precursor protein (APP. While mutations in APP lead to the development of Familial Alzheimer's Disease (FAD, sporadic AD has only one clear genetic modifier: the ε4 allele of the apolipoprotein E (ApoE gene. Cholesterol starvation in Caenorhabditis elegans leads to molting and arrest phenotypes similar to loss-of-function mutants of the APP ortholog, apl-1 (amyloid precursor-like protein 1, and lrp-1 (lipoprotein receptor-related protein 1, suggesting a potential interaction between apl-1 and cholesterol metabolism. METHODOLOGY/PRINCIPAL FINDINGS: Previously, we found that RNAi knock-down of apl-1 leads to aldicarb hypersensitivity, indicating a defect in synaptic function. Here we find the same defect is recapitulated during lrp-1 knock-down and by cholesterol starvation. A cholesterol-free diet or loss of lrp-1 directly affects APL-1 levels as both lead to loss of APL-1::GFP fluorescence in neurons. However, loss of cholesterol does not affect global transcription or protein levels as seen by qPCR and Western blot. CONCLUSIONS: Our results show that cholesterol and lrp-1 are involved in the regulation of synaptic transmission, similar to apl-1. Both are able to modulate APL-1 protein levels in neurons, however cholesterol changes do not affect global apl-1 transcription or APL-1 protein indicating the changes are specific to neurons. Thus, regulation of synaptic transmission and molting by LRP-1 and cholesterol may be mediated by their ability to control APL-1 neuronal protein expression.

  17. PACAP decides neuronal laminar fate via PKA signaling in the developing cerebral cortex

    International Nuclear Information System (INIS)

    Ohtsuka, Masanari; Fukumitsu, Hidefumi; Furukawa, Shoei

    2008-01-01

    Laminar formation in the developing cerebral cortex requires the precisely regulated generation of phenotype-specified neurons. To test the possible involvement of pituitary adenylate cyclase-activating polypeptide (PACAP) in this formation, we investigated the effects of PACAP administered into the telencephalic ventricular space of 13.5-day-old mouse embryos. PACAP partially inhibited the proliferation of cortical progenitors and altered the position and gene-expression profiles of newly generated neurons otherwise expected for layer IV to those of neurons for the deeper layers, V and VI, of the cerebral cortex. The former and latter effects were seen only when the parent progenitor cells were exposed to PACAP in the later and in earlier G1 phase, respectively; and these effects were suppressed by co-treatment with a protein kinase A (PKA) inhibitor. These observations suggest that PACAP participates in the processes forming the neuronal laminas in the developing cortex via the intracellular PKA pathway

  18. A Wnt1 regulated Frizzled-1/β-Catenin signaling pathway as a candidate regulatory circuit controlling mesencephalic dopaminergic neuron-astrocyte crosstalk: Therapeutical relevance for neuron survival and neuroprotection

    Directory of Open Access Journals (Sweden)

    Pluchino Stefano

    2011-07-01

    Full Text Available Abstract Background Dopamine-synthesizing (dopaminergic, DA neurons in the ventral midbrain (VM constitute a pivotal neuronal population controlling motor behaviors, cognitive and affective brain functions, which generation critically relies on the activation of Wingless-type MMTV integration site (Wnt/β-catenin pathway in their progenitors. In Parkinson's disease, DA cell bodies within the substantia nigra pars compacta (SNpc progressively degenerate, with causes and mechanisms poorly understood. Emerging evidence suggests that Wnt signaling via Frizzled (Fzd receptors may play a role in different degenerative states, but little is known about Wnt signaling in the adult midbrain. Using in vitro and in vivo model systems of DA degeneration, along with functional studies in both intact and SN lesioned mice, we herein highlight an intrinsic Wnt1/Fzd-1/β-catenin tone critically contributing to the survival and protection of adult midbrain DA neurons. Results In vitro experiments identifie Fzd-1 receptor expression at a mRNA and protein levels in dopamine transporter (DAT expressing neurons, and demonstrate the ability of exogenous Wnt1 to exert robust neuroprotective effects against Caspase-3 activation, the loss of tyrosine hydroxylase-positive (TH+ neurons and [3H] dopamine uptake induced by different DA-specific insults, including serum and growth factor deprivation, 6-hydroxydopamine and MPTP/MPP+. Co-culture of DA neurons with midbrain astrocytes phenocopies Wnt1 neuroprotective effects, whereas RNA interference-mediated knockdown of Wnt1 in midbrain astrocytes markedly reduces astrocyte-induced TH+ neuroprotection. Likewise, silencing β-catenin mRNA or knocking down Fzd-1 receptor expression in mesencephalic neurons counteract astrocyte-induced TH+ neuroprotection. In vivo experiments document Fzd-1 co-localization with TH+ neurons within the intact SNpc and blockade of Fzd/β-catenin signaling by unilateral infusion of a Fzd

  19. Neurokinin-1 enables measles virus trans-synaptic spread in neurons

    International Nuclear Information System (INIS)

    Makhortova, Nina R.; Askovich, Peter; Patterson, Catherine E.; Gechman, Lisa A.; Gerard, Norma P.; Rall, Glenn F.

    2007-01-01

    Measles virus (MV), a morbillivirus that remains a significant human pathogen, can infect the central nervous system, resulting in rare but often fatal diseases, such as subacute sclerosing panencephalitis. Previous work demonstrated that MV was transmitted trans-synaptically and that, while a cellular receptor for the hemagglutinin (H) protein was required for MV entry, it was dispensable for subsequent cell-to-cell spread. Here, we explored what role the other envelope protein, fusion (F), played in trans-synaptic transport. We made the following observations: (1) MV-F expression in infected neurons was similar to that seen in infected fibroblasts; (2) fusion inhibitory peptide (FIP), an inhibitor of MV fusion, prevented both infection and spread in primary neurons; (3) Substance P, a neurotransmitter with the same active site as FIP, also blocked neuronal MV spread; and (4) both genetic deletion and pharmacological inhibition of the Substance P receptor, neurokinin-1 (NK-1), reduced infection of susceptible mice. Together, these data implicate a role for NK-1 in MV CNS infection and spread, perhaps serving as an MV-F receptor or co-receptor on neurons

  20. 29 CFR 4.2 - Payment of minimum wage specified in section 6(a)(1) of the Fair Labor Standards Act of 1938...

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Payment of minimum wage specified in section 6(a)(1) of the... and Procedures § 4.2 Payment of minimum wage specified in section 6(a)(1) of the Fair Labor Standards... employees shall pay any employees engaged in such work less than the minimum wage specified in section 6(a...

  1. V1 spinal neurons regulate the speed of vertebrate locomotor outputs

    DEFF Research Database (Denmark)

    Gosgnach, Simon; Lanuza, Guillermo M.; Butt, Simon J B

    2006-01-01

    The neuronal networks that generate vertebrate movements such as walking and swimming are embedded in the spinal cord1-3. These networks, which are referred to as central pattern generators (CPGs), are ideal systems for determining how ensembles of neurons generate simple behavioural outputs...... for inhibition in regulating the frequency of the locomotor CPG rhythm, and also suggest that V1 neurons may have an evolutionarily conserved role in controlling the speed of vertebrate locomotor movements....

  2. The zinc finger E-box-binding homeobox 1 (Zeb1) promotes the conversion of mouse fibroblasts into functional neurons.

    Science.gov (United States)

    Yan, Long; Li, Yue; Shi, Zixiao; Lu, Xiaoyin; Ma, Jiao; Hu, Baoyang; Jiao, Jianwei; Wang, Hongmei

    2017-08-04

    The zinc finger E-box-binding transcription factor Zeb1 plays a pivotal role in the epithelial-mesenchymal transition. Numerous studies have focused on the molecular mechanisms by which Zeb1 contributes to this process. However, the functions of Zeb1 beyond the epithelial-mesenchymal transition remain largely elusive. Using a transdifferentiation system to convert mouse embryonic fibroblasts (MEFs) into functional neurons via the neuronal transcription factors achaete-scute family bHLH (basic helix-loop-helix) transcription factor1 ( Ascl1 ), POU class 3 homeobox 2 (POU3F2/ Brn2 ), and neurogenin 2 (Neurog2, Ngn2 ) (ABN), we found that Zeb1 was up-regulated during the early stages of transdifferentiation. Knocking down Zeb1 dramatically attenuated the transdifferentiation efficiency, whereas Zeb1 overexpression obviously increased the efficiency of transdifferentiation from MEFs to neurons. Interestingly, Zeb1 improved the transdifferentiation efficiency induced by even a single transcription factor ( e.g. Asc1 or Ngn2 ). Zeb1 also rapidly promoted the maturation of induced neuron cells to functional neurons and improved the formation of neuronal patterns and electrophysiological characteristics. Induced neuron cells could form functional synapse in vivo after transplantation. Genome-wide RNA arrays showed that Zeb1 overexpression up-regulated the expression of neuron-specific genes and down-regulated the expression of epithelial-specific genes during conversion. Taken together, our results reveal a new role for Zeb1 in the transdifferentiation of MEFs into neurons. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Protective role of AgRP neuron's PDK1 against salt-induced hypertension.

    Science.gov (United States)

    Zhang, Boyang; Nakata, Masanori; Lu, Ming; Nakae, Jun; Okada, Takashi; Ogawa, Wataru; Yada, Toshihiko

    2018-06-12

    In the hypothalamic arcuate nucleus (ARC), orexigenic agouti-related peptide (AgRP) neurons regulate feeding behavior and energy homeostasis. The 3-phosphoinositide-dependent protein kinase-1 (PDK1) in AgRP neurons serves as a major signaling molecule for leptin and insulin, the hormones regulating feeding behavior, energy homeostasis and circulation. However, it is unclear whether PDK1 in AGRP neurons is also involved in regulation of blood pressure. This study explored it by generating and analyzing AgRP neuron-specific PDK1 knockout (Agrp-Pdk1 flox/flox ) mice and effect of high salt diet on blood pressure in KO and WT mice was analyzed. Under high salt diet feeding, systolic blood pressure (SBP) of Agrp-Pdk1 flox/flox mice was significantly elevated compared to Agrp-Cre mice. When the high salt diet was switched to control low salt diet, SBP of Agrp-Pdk1 flox/flox mice returned to the basal level observed in Agrp-Cre mice within 1 week. In Agrp-Pdk1 flox/flox mice, urinary noradrenalin excretion and NUCB2 mRNA expression in hypothalamic paraventricular nucleus (PVN) were markedly upregulated. Moreover, silencing of NUCB2 in the PVN counteracted the rises in urinary noradrenalin excretions and SBP. These results demonstrate a novel role of PDK1 in AgRP neurons to counteract the high salt diet-induced hypertension by preventing hyperactivation of PVN nesfatin-1 neurons. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Deletion of Lkb1 in pro-opiomelanocortin neurons impairs peripheral glucose homeostasis in mice.

    Science.gov (United States)

    Claret, Marc; Smith, Mark A; Knauf, Claude; Al-Qassab, Hind; Woods, Angela; Heslegrave, Amanda; Piipari, Kaisa; Emmanuel, Julian J; Colom, André; Valet, Philippe; Cani, Patrice D; Begum, Ghazala; White, Anne; Mucket, Phillip; Peters, Marco; Mizuno, Keiko; Batterham, Rachel L; Giese, K Peter; Ashworth, Alan; Burcelin, Remy; Ashford, Michael L; Carling, David; Withers, Dominic J

    2011-03-01

    AMP-activated protein kinase (AMPK) signaling acts as a sensor of nutrients and hormones in the hypothalamus, thereby regulating whole-body energy homeostasis. Deletion of Ampkα2 in pro-opiomelanocortin (POMC) neurons causes obesity and defective neuronal glucose sensing. LKB1, the Peutz-Jeghers syndrome gene product, and Ca(2+)-calmodulin-dependent protein kinase kinase β (CaMKKβ) are key upstream activators of AMPK. This study aimed to determine their role in POMC neurons upon energy and glucose homeostasis regulation. Mice lacking either Camkkβ or Lkb1 in POMC neurons were generated, and physiological, electrophysiological, and molecular biology studies were performed. Deletion of Camkkβ in POMC neurons does not alter energy homeostasis or glucose metabolism. In contrast, female mice lacking Lkb1 in POMC neurons (PomcLkb1KO) display glucose intolerance, insulin resistance, impaired suppression of hepatic glucose production, and altered expression of hepatic metabolic genes. The underlying cellular defect in PomcLkb1KO mice involves a reduction in melanocortin tone caused by decreased α-melanocyte-stimulating hormone secretion. However, Lkb1-deficient POMC neurons showed normal glucose sensing, and body weight was unchanged in PomcLkb1KO mice. Our findings demonstrate that LKB1 in hypothalamic POMC neurons plays a key role in the central regulation of peripheral glucose metabolism but not body-weight control. This phenotype contrasts with that seen in mice lacking AMPK in POMC neurons with defects in body-weight regulation but not glucose homeostasis, which suggests that LKB1 plays additional functions distinct from activating AMPK in POMC neurons.

  5. Cells from the adult corneal stroma can be reprogrammed to a neuron-like cell using exogenous growth factors

    Energy Technology Data Exchange (ETDEWEB)

    Greene, Carol Ann, E-mail: carol.greene@auckland.ac.nz; Chang, Chuan-Yuan; Fraser, Cameron J.; Nelidova, Dasha E.; Chen, Jing A.; Lim, Angela; Brebner, Alex; McGhee, Jennifer; Sherwin, Trevor; Green, Colin R.

    2014-03-10

    Cells thought to be stem cells isolated from the cornea of the eye have been shown to exhibit neurogenic potential. We set out to uncover the identity and location of these cells within the cornea and to elucidate their neuronal protein and gene expression profile during the process of switching to a neuron-like cell. Here we report that every cell of the adult human and rat corneal stroma is capable of differentiating into a neuron-like cell when treated with neurogenic differentiation specifying growth factors. Furthermore, the expression of genes regulating neurogenesis and mature neuronal structure and function was increased. The switch from a corneal stromal cell to a neuron-like cell was also shown to occur in vivo in intact corneas of living rats. Our results clearly indicate that lineage specifying growth factors can affect changes in the protein and gene expression profiles of adult cells, suggesting that possibly many adult cell populations can be made to switch into another type of mature cell by simply modifying the growth factor environment. - Highlights: • Adult corneal stromal cells can differentiated into neuron-like cells. • Neuronal specification of the adult stromal cell population is stochastic. • Neuronal specification in an adult cell population can be brought about by growth factors.

  6. Cells from the adult corneal stroma can be reprogrammed to a neuron-like cell using exogenous growth factors

    International Nuclear Information System (INIS)

    Greene, Carol Ann; Chang, Chuan-Yuan; Fraser, Cameron J.; Nelidova, Dasha E.; Chen, Jing A.; Lim, Angela; Brebner, Alex; McGhee, Jennifer; Sherwin, Trevor; Green, Colin R.

    2014-01-01

    Cells thought to be stem cells isolated from the cornea of the eye have been shown to exhibit neurogenic potential. We set out to uncover the identity and location of these cells within the cornea and to elucidate their neuronal protein and gene expression profile during the process of switching to a neuron-like cell. Here we report that every cell of the adult human and rat corneal stroma is capable of differentiating into a neuron-like cell when treated with neurogenic differentiation specifying growth factors. Furthermore, the expression of genes regulating neurogenesis and mature neuronal structure and function was increased. The switch from a corneal stromal cell to a neuron-like cell was also shown to occur in vivo in intact corneas of living rats. Our results clearly indicate that lineage specifying growth factors can affect changes in the protein and gene expression profiles of adult cells, suggesting that possibly many adult cell populations can be made to switch into another type of mature cell by simply modifying the growth factor environment. - Highlights: • Adult corneal stromal cells can differentiated into neuron-like cells. • Neuronal specification of the adult stromal cell population is stochastic. • Neuronal specification in an adult cell population can be brought about by growth factors

  7. Morphological Analysis of the Axonal Projections of EGFP-Labeled Esr1-Expressing Neurons in Transgenic Female Medaka.

    Science.gov (United States)

    Zempo, Buntaro; Karigo, Tomomi; Kanda, Shinji; Akazome, Yasuhisa; Oka, Yoshitaka

    2018-02-01

    Some hypothalamic neurons expressing estrogen receptor α (Esr1) are thought to transmit a gonadal estrogen feedback signal to gonadotropin-releasing hormone 1 (GnRH1) neurons, which is the final common pathway for feedback regulation of reproductive functions. Moreover, estrogen-sensitive neurons are suggested to control sexual behaviors in coordination with reproduction. In mammals, hypothalamic estrogen-sensitive neurons release the peptide kisspeptin and regulate GnRH1 neurons. However, a growing body of evidence in nonmammalian species casts doubt on the regulation of GnRH1 neurons by kisspeptin neurons. As a step toward understanding how estrogen regulates neuronal circuits for reproduction and sex behavior in vertebrates in general, we generated a transgenic (Tg) medaka that expresses enhanced green fluorescent protein (EGFP) specifically in esr1-expressing neurons (esr1 neurons) and analyzed their axonal projections. We found that esr1 neurons in the preoptic area (POA) project to the gnrh1 neurons. We also demonstrated by transcriptome and histological analyses that these esr1 neurons are glutamatergic or γ-aminobutyric acidergic (GABAergic) but not kisspeptinergic. We therefore suggest that glutamatergic and GABAergic esr1 neurons in the POA regulate gnrh1 neurons. This hypothesis is consistent with previous studies in mice that found that glutamatergic and GABAergic transmission is critical for estrogen-dependent changes in GnRH1 neuron firing. Thus, we propose that this neuronal circuit may provide an evolutionarily conserved mechanism for regulation of reproduction. In addition, we showed that telencephalic esr1 neurons project to medulla, which may control sexual behavior. Moreover, we found that some POA-esr1 neurons coexpress progesterone receptors. These neurons may form the neuronal circuits that regulate reproduction and sex behavior in response to the serum estrogen/progesterone. Copyright © 2018 Endocrine Society.

  8. Deletion of Lkb1 in Pro-Opiomelanocortin Neurons Impairs Peripheral Glucose Homeostasis in Mice

    Science.gov (United States)

    Claret, Marc; Smith, Mark A.; Knauf, Claude; Al-Qassab, Hind; Woods, Angela; Heslegrave, Amanda; Piipari, Kaisa; Emmanuel, Julian J.; Colom, André; Valet, Philippe; Cani, Patrice D.; Begum, Ghazala; White, Anne; Mucket, Phillip; Peters, Marco; Mizuno, Keiko; Batterham, Rachel L.; Giese, K. Peter; Ashworth, Alan; Burcelin, Remy; Ashford, Michael L.; Carling, David; Withers, Dominic J.

    2011-01-01

    OBJECTIVE AMP-activated protein kinase (AMPK) signaling acts as a sensor of nutrients and hormones in the hypothalamus, thereby regulating whole-body energy homeostasis. Deletion of Ampkα2 in pro-opiomelanocortin (POMC) neurons causes obesity and defective neuronal glucose sensing. LKB1, the Peutz-Jeghers syndrome gene product, and Ca2+-calmodulin–dependent protein kinase kinase β (CaMKKβ) are key upstream activators of AMPK. This study aimed to determine their role in POMC neurons upon energy and glucose homeostasis regulation. RESEARCH DESIGN AND METHODS Mice lacking either Camkkβ or Lkb1 in POMC neurons were generated, and physiological, electrophysiological, and molecular biology studies were performed. RESULTS Deletion of Camkkβ in POMC neurons does not alter energy homeostasis or glucose metabolism. In contrast, female mice lacking Lkb1 in POMC neurons (PomcLkb1KO) display glucose intolerance, insulin resistance, impaired suppression of hepatic glucose production, and altered expression of hepatic metabolic genes. The underlying cellular defect in PomcLkb1KO mice involves a reduction in melanocortin tone caused by decreased α-melanocyte–stimulating hormone secretion. However, Lkb1-deficient POMC neurons showed normal glucose sensing, and body weight was unchanged in PomcLkb1KO mice. CONCLUSIONS Our findings demonstrate that LKB1 in hypothalamic POMC neurons plays a key role in the central regulation of peripheral glucose metabolism but not body-weight control. This phenotype contrasts with that seen in mice lacking AMPK in POMC neurons with defects in body-weight regulation but not glucose homeostasis, which suggests that LKB1 plays additional functions distinct from activating AMPK in POMC neurons. PMID:21266325

  9. Role of CB1 cannabinoid receptors on GABAergic neurons in brain aging.

    Science.gov (United States)

    Albayram, Onder; Alferink, Judith; Pitsch, Julika; Piyanova, Anastasia; Neitzert, Kim; Poppensieker, Karola; Mauer, Daniela; Michel, Kerstin; Legler, Anne; Becker, Albert; Monory, Krisztina; Lutz, Beat; Zimmer, Andreas; Bilkei-Gorzo, Andras

    2011-07-05

    Brain aging is associated with cognitive decline that is accompanied by progressive neuroinflammatory changes. The endocannabinoid system (ECS) is involved in the regulation of glial activity and influences the progression of age-related learning and memory deficits. Mice lacking the Cnr1 gene (Cnr1(-/-)), which encodes the cannabinoid receptor 1 (CB1), showed an accelerated age-dependent deficit in spatial learning accompanied by a loss of principal neurons in the hippocampus. The age-dependent decrease in neuronal numbers in Cnr1(-/-) mice was not related to decreased neurogenesis or to epileptic seizures. However, enhanced neuroinflammation characterized by an increased density of astrocytes and activated microglia as well as an enhanced expression of the inflammatory cytokine IL-6 during aging was present in the hippocampus of Cnr1(-/-) mice. The ongoing process of pyramidal cell degeneration and neuroinflammation can exacerbate each other and both contribute to the cognitive deficits. Deletion of CB1 receptors from the forebrain GABAergic, but not from the glutamatergic neurons, led to a similar neuronal loss and increased neuroinflammation in the hippocampus as observed in animals lacking CB1 receptors in all cells. Our results suggest that CB1 receptor activity on hippocampal GABAergic neurons protects against age-dependent cognitive decline by reducing pyramidal cell degeneration and neuroinflammation.

  10. Antioxidant enzyme gene delivery to protect from HIV-1 gp120-induced neuronal apoptosis.

    Science.gov (United States)

    Agrawal, L; Louboutin, J-P; Reyes, B A S; Van Bockstaele, E J; Strayer, D S

    2006-12-01

    Human immunodeficiency virus-1 (HIV-1) infection in the central nervous system (CNS) may lead to neuronal loss and progressively deteriorating CNS function: HIV-1 gene products, especially gp120, induce free radical-mediated apoptosis. Reactive oxygen species (ROS), are among the potential mediators of these effects. Neurons readily form ROS after gp120 exposure, and so might be protected from ROS-mediated injury by antioxidant enzymes such as Cu/Zn-superoxide dismutase (SOD1) and/or glutathione peroxidase (GPx1). Both enzymes detoxify oxygen free radicals. As they are highly efficient gene delivery vehicles for neurons, recombinant SV40-derived vectors were used for these studies. Cultured mature neurons derived from NT2 cells and primary fetal neurons were transduced with rSV40 vectors carrying human SOD1 and/or GPx1 cDNAs, then exposed to gp120. Apoptosis was measured by terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay. Transduction efficiency of both neuron populations was >95%, as assayed by immunostaining. Transgene expression was also ascertained by Western blotting and direct assays of enzyme activity. Gp120 induced apoptosis in a high percentage of unprotected NT2-N. Transduction with SV(SOD1) and SV(GPx1) before gp120 challenge reduced neuronal apoptosis by >90%. Even greater protection was seen in cells treated with both vectors in sequence. Given singly or in combination, they protect neuronal cells from HIV-1-gp120 induced apoptosis. We tested whether rSV40 s can deliver antioxidant enzymes to the CNS in vivo: intracerebral injection of SV(SOD1) or SV(GPx1) into the caudate putamen of rat brain yielded excellent transgene expression in neurons. In vivo transduction using SV(SOD1) also protected neurons from subsequent gp120-induced apoptosis after injection of both into the caudate putamen of rat brain. Thus, SOD1 and GPx1 can be delivered by SV40 vectors in vitro or in vivo. This approach may merit consideration for

  11. Leptin and insulin engage specific PI3K subunits in hypothalamic SF1 neurons

    Directory of Open Access Journals (Sweden)

    Jong-Woo Sohn

    2016-08-01

    Full Text Available Objective: The ventromedial hypothalamic nucleus (VMH regulates energy balance and glucose homeostasis. Leptin and insulin exert metabolic effects via their cognate receptors expressed by the steroidogenic factor 1 (SF1 neurons within the VMH. However, detailed cellular mechanisms involved in the regulation of these neurons by leptin and insulin remain to be identified. Methods: We utilized genetically-modified mouse models and performed patch-clamp electrophysiology experiments to resolve this issue. Results: We identified distinct populations of leptin-activated and leptin-inhibited SF1 neurons. In contrast, insulin uniformly inhibited SF1 neurons. Notably, we found that leptin-activated, leptin-inhibited, and insulin-inhibited SF1 neurons are distinct subpopulations within the VMH. Leptin depolarization of SF1 neuron also required the PI3K p110β catalytic subunit. This effect was mediated by the putative transient receptor potential C (TRPC channel. On the other hand, hyperpolarizing responses of SF1 neurons by leptin and insulin required either of the p110α or p110β catalytic subunits, and were mediated by the putative ATP-sensitive K+ (KATP channel. Conclusions: Our results demonstrate that specific PI3K catalytic subunits are responsible for the acute effects of leptin and insulin on VMH SF1 neurons, and provide insights into the cellular mechanisms of leptin and insulin action on VMH SF1 neurons that regulate energy balance and glucose homeostasis. Author Video: Author Video Watch what authors say about their articles Keywords: Cellular mechanism, Conditional knockout mouse, Patch clamp technique, Functional heterogeneity, Homeostasis

  12. Activation of CRH receptor type 1 expressed on glutamatergic neurons increases excitability of CA1 pyramidal neurons by the modulation of voltage-gated ion channels

    Directory of Open Access Journals (Sweden)

    Stephan eKratzer

    2013-07-01

    Full Text Available Corticotropin-releasing hormone (CRH plays an important role in a substantial number of patients with stress-related mental disorders, such as anxiety disorders and depression. CRH has been shown to increase neuronal excitability in the hippocampus, but the underlying mechanisms are poorly understood. The effects of CRH on neuronal excitability were investigated in acute hippocampal brain slices. Population spikes (PS and field excitatory postsynaptic potentials (fEPSP were evoked by stimulating Schaffer-collaterals and recorded simultaneously from the somatic and dendritic region of CA1 pyramidal neurons. CRH was found to increase PS amplitudes (mean  Standard error of the mean; 231.8  31.2% of control; n=10 while neither affecting fEPSPs (104.3 ± 4.2%; n=10 nor long-term potentiation (LTP. However, when Schaffer-collaterals were excited via action potentials (APs generated by stimulation of CA3 pyramidal neurons, CRH increased fEPSP amplitudes (119.8 ± 3.6%; n=8 and the magnitude of LTP in the CA1 region. Experiments in slices from transgenic mice revealed that the effect on PS amplitude is mediated exclusively by CRH receptor 1 (CRHR1 expressed on glutamatergic neurons. The effects of CRH on PS were dependent on phosphatase-2B, L- and T-type calcium channels and voltage-gated potassium channels but independent on intracellular Ca2+-elevation. In patch-clamp experiments, CRH increased the frequency and decay times of APs and decreased currents through A-type and delayed-rectifier potassium channels. These results suggest that CRH does not affect synaptic transmission per se, but modulates voltage-gated ion currents important for the generation of APs and hence elevates by this route overall neuronal activity.

  13. Decreased α1-adrenergic receptor-mediated inositide hydrolysis in neurons from hypertensive rat brain

    International Nuclear Information System (INIS)

    Feldstein, J.B.; Gonzales, R.A.; Baker, S.P.; Sumners, C.; Crews, F.T.; Raizada, M.K.

    1986-01-01

    The expression of α 1 -adrenergic receptors and norepinephrine (NE)-stimulated hydrolysis of inositol phospholipid has been studied in neuronal cultures from the brains of normotensive (Wistar-Kyoto, WKY) and spontaneously hypertensive (SH) rats. Binding of 125 I-1-[β-(4-hydroxyphenyl)-ethyl-aminomethyl] tetralone (HEAT) to neuronal membranes was 68-85% specific and was rapid. Competition-inhibition experiments with various agonists and antagonists suggested that 125 I-HEAT bound selectively to α 1 -adrenergic receptors. Specific binding of 125 I-HEAT to neuronal membranes from SH rat brain cultures was 30-45% higher compared with binding in WKY normotensive controls. This increase was attributed to an increase in the number of α 1 -adrenergic receptors on SH rat brain neurons. Incubation of neuronal cultures of rat brain from both strains with NE resulted in a concentration-dependent stimulation of release of inositol phosphates, although neurons from SH rat brains were 40% less responsive compared with WKY controls. The decrease in responsiveness of SH rat brain neurons to NE, even though the α 1 -adrenergic receptors are increased, does not appear to be due to a general defect in membrane receptors and postreceptor signal transduction mechanisms. This is because neither the number of muscarinic-cholinergic receptors nor the carbachol-stimulated release of inositol phosphates is different in neuronal cultures from the brains of SH rats compared with neuronal cultures from the brains of WKY rats. These observations suggest that the increased expression of α 1 -adrenergic receptors does not parallel the receptor-mediated inositol phosphate hydrolysis in neuronal cultures from SH rat brain

  14. Nrdp1 Increases Ischemia Induced Primary Rat Cerebral Cortical Neurons and Pheochromocytoma Cells Apoptosis Via Downregulation of HIF-1α Protein

    Directory of Open Access Journals (Sweden)

    Yuan Zhang

    2017-09-01

    Full Text Available Neuregulin receptor degradation protein-1 (Nrdp1 is an E3 ubiquitin ligase that targets proteins for degradation and regulates cell growth, apoptosis and oxidative stress in various cell types. We have previously shown that Nrdp1 is implicated in ischemic cardiomyocyte death. In this study, we investigated the change of Nrdp1 expression in ischemic neurons and its role in ischemic neuronal injury. Primary rat cerebral cortical neurons and pheochromocytoma (PC12 cells were infected with adenoviral constructs expressing Nrdp1 gene or its siRNA before exposing to oxygen-glucose deprivation (OGD treatment. Our data showed that Nrdp1 was upregulated in ischemic brain tissue 3 h after middle cerebral artery occlusion (MCAO and in OGD-treated neurons. Of note, Nrdp1 overexpression by Ad-Nrdp1 enhanced OGD-induced neuron apoptosis, while knockdown of Nrdp1 with siRNA attenuated this effect, implicating a role of Nrdp1 in ischemic neuron injury. Moreover, Nrdp1 upregulation is accompanied by increased protein ubiquitylation and decreased protein levels of ubiquitin-specific protease 8 (USP8 in OGD-treated neurons, which led to a suppressed interaction between USP8 and HIF-1α and subsequently a reduction in HIF-1α protein accumulation in neurons under OGD conditions. In conclusion, our data support an important role of Nrdp1 upregulation in ischemic neuronal death, and suppressing the interaction between USP8 and HIF-1α and consequently the hypoxic adaptive response of neurons may account for this detrimental effect.

  15. Endothelial HIF-1α Enables Hypothalamic Glucose Uptake to Drive POMC Neurons.

    Science.gov (United States)

    Varela, Luis; Suyama, Shigetomo; Huang, Yan; Shanabrough, Marya; Tschöp, Matthias H; Gao, Xiao-Bing; Giordano, Frank J; Horvath, Tamas L

    2017-06-01

    Glucose is the primary driver of hypothalamic proopiomelanocortin (POMC) neurons. We show that endothelial hypoxia-inducible factor 1α (HIF-1α) controls glucose uptake in the hypothalamus and that it is upregulated in conditions of undernourishment, during which POMC neuronal activity is decreased. Endothelium-specific knockdown of HIF-1α impairs the ability of POMC neurons to adapt to the changing metabolic environment in vivo, resulting in overeating after food deprivation in mice. The impaired functioning of POMC neurons was reversed ex vivo or by parenchymal glucose administration. These observations indicate an active role for endothelial cells in the central control of metabolism and suggest that central vascular impairments may cause metabolic disorders. © 2017 by the American Diabetes Association.

  16. CNF1 Improves Astrocytic Ability to Support Neuronal Growth and Differentiation In vitro

    OpenAIRE

    Malchiodi-Albedi, Fiorella; Paradisi, Silvia; Di Nottia, Michela; Simone, Daiana; Travaglione, Sara; Falzano, Loredana; Guidotti, Marco; Frank, Claudio; Cutarelli, Alessandro; Fabbri, Alessia; Fiorentini, Carla

    2012-01-01

    Modulation of cerebral Rho GTPases activity in mice brain by intracerebral administration of Cytotoxic Necrotizing Factor 1 (CNF1) leads to enhanced neurotransmission and synaptic plasticity and improves learning and memory. To gain more insight into the interactions between CNF1 and neuronal cells, we used primary neuronal and astrocytic cultures from rat embryonic brain to study CNF1 effects on neuronal differentiation, focusing on dendritic tree growth and synapse formation, which are stri...

  17. Neuronal Antibodies in Children with or without Narcolepsy following H1N1-AS03 Vaccination.

    Directory of Open Access Journals (Sweden)

    Simon Thebault

    Full Text Available Type 1 narcolepsy is caused by deficiency of hypothalamic orexin/hypocretin. An autoimmune basis is suspected, but no specific antibodies, either causative or as biomarkers, have been identified. However, the AS03 adjuvanted split virion H1N1 (H1N1-AS03 vaccine, created to protect against the 2009 Pandemic, has been implicated as a trigger of narcolepsy particularly in children. Sera and CSFs from 13 H1N1-AS03-vaccinated patients (12 children, 1 young adult with type 1 narcolepsy were tested for autoantibodies to known neuronal antigens including the N-methyl-D-aspartate receptor (NMDAR and contactin-associated protein 2 (CASPR2, both associated with encephalopathies that include disordered sleep, to rodent brain tissue including the lateral hypothalamus, and to live hippocampal neurons in culture. When sufficient sample was available, CSF levels of melanin-concentrating hormone (MCH were measured. Sera from 44 H1N1-ASO3-vaccinated children without narcolepsy were also examined. None of these patients' CSFs or sera was positive for NMDAR or CASPR2 antibodies or binding to neurons; 4/13 sera bound to orexin-neurons in rat brain tissue, but also to other neurons. MCH levels were a marginally raised (n = 8; p = 0.054 in orexin-deficient narcolepsy patients compared with orexin-normal children (n = 6. In the 44 H1N1-AS03-vaccinated healthy children, there was no rise in total IgG levels or in CASPR2 or NMDAR antibodies three weeks following vaccination. In conclusion, there were no narcolepsy-specific autoantibodies identified in type 1 narcolepsy sera or CSFs, and no evidence for a general increase in immune reactivity following H1N1-AS03 vaccination in the healthy children. Antibodies to other neuronal specific membrane targets, with their potential for directing use of immunotherapies, are still an important goal for future research.

  18. Neuronal Antibodies in Children with or without Narcolepsy following H1N1-AS03 Vaccination.

    Science.gov (United States)

    Thebault, Simon; Waters, Patrick; Snape, Matthew D; Cottrell, Dominic; Darin, Niklas; Hallböök, Tove; Huutoniemi, Anne; Partinen, Markku; Pollard, Andrew J; Vincent, Angela

    2015-01-01

    Type 1 narcolepsy is caused by deficiency of hypothalamic orexin/hypocretin. An autoimmune basis is suspected, but no specific antibodies, either causative or as biomarkers, have been identified. However, the AS03 adjuvanted split virion H1N1 (H1N1-AS03) vaccine, created to protect against the 2009 Pandemic, has been implicated as a trigger of narcolepsy particularly in children. Sera and CSFs from 13 H1N1-AS03-vaccinated patients (12 children, 1 young adult) with type 1 narcolepsy were tested for autoantibodies to known neuronal antigens including the N-methyl-D-aspartate receptor (NMDAR) and contactin-associated protein 2 (CASPR2), both associated with encephalopathies that include disordered sleep, to rodent brain tissue including the lateral hypothalamus, and to live hippocampal neurons in culture. When sufficient sample was available, CSF levels of melanin-concentrating hormone (MCH) were measured. Sera from 44 H1N1-ASO3-vaccinated children without narcolepsy were also examined. None of these patients' CSFs or sera was positive for NMDAR or CASPR2 antibodies or binding to neurons; 4/13 sera bound to orexin-neurons in rat brain tissue, but also to other neurons. MCH levels were a marginally raised (n = 8; p = 0.054) in orexin-deficient narcolepsy patients compared with orexin-normal children (n = 6). In the 44 H1N1-AS03-vaccinated healthy children, there was no rise in total IgG levels or in CASPR2 or NMDAR antibodies three weeks following vaccination. In conclusion, there were no narcolepsy-specific autoantibodies identified in type 1 narcolepsy sera or CSFs, and no evidence for a general increase in immune reactivity following H1N1-AS03 vaccination in the healthy children. Antibodies to other neuronal specific membrane targets, with their potential for directing use of immunotherapies, are still an important goal for future research.

  19. A possible role of the non-GAT1 GABA transporters in transfer of GABA from GABAergic to glutamatergic neurons in mouse cerebellar neuronal cultures

    DEFF Research Database (Denmark)

    Suñol, C; Babot, Z; Cristòfol, R

    2010-01-01

    Cultures of dissociated cerebellum from 7-day-old mice were used to investigate the mechanism involved in synthesis and cellular redistribution of GABA in these cultures consisting primarily of glutamatergic granule neurons and a smaller population of GABAergic Golgi and stellate neurons......3 transporters. Only a small population of cells were immuno-stained for GAD while many cells exhibited VGlut-1 like immuno-reactivity which, however, never co-localized with GAD positive neurons. This likely reflects the small number of GABAergic neurons compared to the glutamatergic granule......M concentrations (95%). Essentially all neurons showed GABA like immunostaining albeit with differences in intensity. The results indicate that GABA which is synthesized in a small population of GAD-positive neurons is redistributed to essentially all neurons including the glutamatergic granule cells. GAT1...

  20. Carbon Monoxide Releasing Molecule-A1 (CORM-A1) Improves Neurogenesis: Increase of Neuronal Differentiation Yield by Preventing Cell Death.

    Science.gov (United States)

    Almeida, Ana S; Soares, Nuno L; Vieira, Melissa; Gramsbergen, Jan Bert; Vieira, Helena L A

    2016-01-01

    Cerebral ischemia and neurodegenerative diseases lead to impairment or death of neurons in the central nervous system. Stem cell based therapies are promising strategies currently under investigation. Carbon monoxide (CO) is an endogenous product of heme degradation by heme oxygenase (HO) activity. Administration of CO at low concentrations produces several beneficial effects in distinct tissues, namely anti-apoptotic and anti-inflammatory. Herein the CO role on modulation of neuronal differentiation was assessed. Three different models with increasing complexity were used: human neuroblastoma SH-S5Y5 cell line, human teratocarcinoma NT2 cell line and organotypic hippocampal slice cultures (OHSC). Cell lines were differentiated into post-mitotic neurons by treatment with retinoic acid (RA) supplemented with CO-releasing molecule A1 (CORM-A1). CORM-A1 positively modulated neuronal differentiation, since it increased final neuronal production and enhanced the expression of specific neuronal genes: Nestin, Tuj1 and MAP2. Furthermore, during neuronal differentiation process, there was an increase in proliferative cell number (ki67 mRNA expressing cells) and a decrease in cell death (lower propidium iodide (PI) uptake, limitation of caspase-3 activation and higher Bcl-2 expressing cells). CO supplementation did not increase the expression of RA receptors. In the case of SH-S5Y5 model, small amounts of reactive oxygen species (ROS) generation emerges as important signaling molecules during CO-promoted neuronal differentiation. CO's improvement of neuronal differentiation yield was validated using OHSC as ex vivo model. CORM-A1 treatment of OHSC promoted higher levels of cells expressing the neuronal marker Tuj1. Still, CORM-A1 increased cell proliferation assessed by ki67 expression and also prevented cell death, which was followed by increased Bcl-2 expression, decreased levels of active caspase-3 and PI uptake. Likewise, ROS signaling emerged as key factors in CO

  1. Liraglutide Modulates Appetite and Body Weight Via GLP-1R-Expressing Glutamatergic Neurons.

    Science.gov (United States)

    Adams, Jessica M; Pei, Hongjuan; Sandoval, Darleen A; Seeley, Randy J; Chang, Rui B; Liberles, Stephen D; Olson, David P

    2018-05-18

    Glucagon-like peptide-1 receptor (GLP-1R) agonists are FDA-approved weight loss drugs. Despite their widespread use, the sites of action through which GLP-1R agonists (GLP1RAs) impact appetite and body weight are still not fully understood. Here, we determined whether GLP-1Rs in either GABAergic or glutamatergic neurons are necessary for the acute and chronic effects of the GLP1RA liraglutide on food intake, visceral illness, body weight and neural network activation. We found that mice lacking GLP-1Rs in vGAT -expressing GABAergic neurons responded identically to controls in all parameters measured, whereas deletion of GLP-1Rs in vGlut2 -expressing glutamatergic neurons eliminated liraglutide-induced weight loss and visceral illness and severely attenuated its effects on feeding. Concomitantly, deletion of GLP-1Rs from glutamatergic neurons completely abolished the neural network activation observed after liraglutide administration. We conclude that liraglutide activates a dispersed but discrete neural network to mediate its physiological effects, and that these effects require GLP-1R expression on glutamatergic but not GABAergic neurons. © 2018 by the American Diabetes Association.

  2. PD-L1 expression by neurons nearby tumors indicates better prognosis in glioblastoma patients

    DEFF Research Database (Denmark)

    Liu, Yawei; Carlsson, Robert; Ambjørn, Malene

    2013-01-01

    Glioblastoma multiforme (GBM) is the most aggressive form of brain tumor. In general, tumor growth requires disruption of the tissue microenvironment, yet how this affects glioma progression is unknown. We studied program death-ligand (PD-L)1 in neurons and gliomas in tumors from GBM patients...... and associated the findings with clinical outcome. Remarkably, we found that upregulation of PD-L1 by neurons in tumor-adjacent brain tissue (TABT) associated positively with GBM patient survival, whereas lack of neuronal PD-L1 expression was associated with high PD-L1 in tumors and unfavorable prognosis...... in GBM patients, better survival in wild-type mice was associated with high neuronal PD-L1 in TABT and downregulation of PD-L1 in tumors, which was defective in Ifnb-/- mice. Our data indicated that neuronal PD-L1 signaling in brain cells was important for GBM patient survival. Reciprocal PD-L1...

  3. Neuroprotective effects of curcumin on endothelin-1 mediated cell death in hippocampal neurons.

    Science.gov (United States)

    Stankowska, Dorota L; Krishnamoorthy, Vignesh R; Ellis, Dorette Z; Krishnamoorthy, Raghu R

    2017-06-01

    Alzheimer's disease is a progressive neurodegenerative disease characterized by loss of hippocampal neurons leading to memory deficits and cognitive decline. Studies suggest that levels of the vasoactive peptide endothelin-1 (ET-1) are increased in the brain tissue of Alzheimer's patients. Curcumin, the main ingredient of the spice turmeric, has been shown to have anti-inflammatory, anti-cancer, and neuroprotective effects. However, the mechanisms underlying some of these beneficial effects are not completely understood. The objective of this study was to determine if curcumin could protect hippocampal neurons from ET-1 mediated cell death and examine the involvement of c-Jun in this pathway. Primary hippocampal neurons from rat pups were isolated using a previously published protocol. Viability of the cells was measured by the live/dead assay. Immunoblot and immunohistochemical analyses were performed to analyze c-Jun levels in hippocampal neurons treated with either ET-1 or a combination of ET-1 and curcumin. Apoptotic changes were evaluated by immunoblot detection of cleaved caspase-3, cleaved fodrin, and a caspase 3/7 activation assay. ET-1 treatment produced a 2-fold increase in the levels of c-Jun as determined by an immunoblot analysis in hippocampal neurons. Co-treatment with curcumin significantly attenuated the ET-1 mediated increase in c-Jun levels. ET-1 caused increased neuronal cell death of hippocampal neurons indicated by elevation of cleaved caspase-3, cleaved fodrin and an increased activity of caspases 3 and 7 which was attenuated by co-treatment with curcumin. Blockade of JNK, an upstream effector of c-Jun by specific inhibitor SP600125 did not fully protect from ET-1 mediated activation of pro-apoptotic enzymes in primary hippocampal cells. Our data suggests that one mechanism by which curcumin protects against ET-1-mediated cell death is through blocking an increase in c-Jun levels. Other possible mechanisms include decreasing pro

  4. FoxO1 in dopaminergic neurons regulates energy homeostasis and targets tyrosine hydroxylase

    Science.gov (United States)

    Doan, Khanh V.; Kinyua, Ann W.; Yang, Dong Joo; Ko, Chang Mann; Moh, Sang Hyun; Shong, Ko Eun; Kim, Hail; Park, Sang-Kyu; Kim, Dong-Hoon; Kim, Inki; Paik, Ji-Hye; DePinho, Ronald A.; Yoon, Seul Gi; Kim, Il Yong; Seong, Je Kyung; Choi, Yun-Hee; Kim, Ki Woo

    2016-01-01

    Dopaminergic (DA) neurons are involved in the integration of neuronal and hormonal signals to regulate food consumption and energy balance. Forkhead transcriptional factor O1 (FoxO1) in the hypothalamus plays a crucial role in mediation of leptin and insulin function. However, the homoeostatic role of FoxO1 in DA system has not been investigated. Here we report that FoxO1 is highly expressed in DA neurons and mice lacking FoxO1 specifically in the DA neurons (FoxO1 KODAT) show markedly increased energy expenditure and interscapular brown adipose tissue (iBAT) thermogenesis accompanied by reduced fat mass and improved glucose/insulin homoeostasis. Moreover, FoxO1 KODAT mice exhibit an increased sucrose preference in concomitance with higher dopamine and norepinephrine levels. Finally, we found that FoxO1 directly targets and negatively regulates tyrosine hydroxylase (TH) expression, the rate-limiting enzyme of the catecholamine synthesis, delineating a mechanism for the KO phenotypes. Collectively, these results suggest that FoxO1 in DA neurons is an important transcriptional factor that directs the coordinated control of energy balance, thermogenesis and glucose homoeostasis. PMID:27681312

  5. An ALS-Associated Mutant SOD1 Rapidly Suppresses KCNT1 (Slack) Na+-Activated K+ Channels in Aplysia Neurons.

    Science.gov (United States)

    Zhang, Yalan; Ni, Weiming; Horwich, Arthur L; Kaczmarek, Leonard K

    2017-02-22

    Mutations that alter levels of Slack (KCNT1) Na + -activated K + current produce devastating effects on neuronal development and neuronal function. We now find that Slack currents are rapidly suppressed by oligomers of mutant human Cu/Zn superoxide dismutase 1 (SOD1), which are associated with motor neuron toxicity in an inherited form of amyotrophic lateral sclerosis (ALS). We recorded from bag cell neurons of Aplysia californica , a model system to study neuronal excitability. We found that injection of fluorescent wild-type SOD1 (wt SOD1YFP) or monomeric mutant G85R SOD1YFP had no effect on net ionic currents measured under voltage clamp. In contrast, outward potassium currents were significantly reduced by microinjection of mutant G85R SOD1YFP that had been preincubated at 37°C or of cross-linked dimers of G85R SOD1YFP. Reduction of potassium current was also seen with multimeric G85R SOD1YFP of ∼300 kDa or >300 kDa that had been cross-linked. In current clamp recordings, microinjection of cross-linked 300 kDa increased excitability by depolarizing the resting membrane potential, and decreasing the latency of action potentials triggered by depolarization. The effect of cross-linked 300 kDa on potassium current was reduced by removing Na + from the bath solution, or by knocking down levels of Slack using siRNA. It was also prevented by pharmacological inhibition of ASK1 (apoptosis signal-regulating kinase 1) or of c-Jun N-terminal kinase, but not by an inhibitor of p38 mitogen-activated protein kinase. These results suggest that soluble mutant SOD1 oligomers rapidly trigger a kinase pathway that regulates the activity of Na + -activated K + channels in neurons. SIGNIFICANCE STATEMENT Slack Na + -activated K + channels (KCNT1, K Na 1.1) regulate neuronal excitability but are also linked to cytoplasmic signaling pathways that control neuronal protein translation. Mutations that alter the amplitude of these currents have devastating effects on neuronal

  6. Expression of the transient receptor potential channels TRPV1, TRPA1 and TRPM8 in mouse trigeminal primary afferent neurons innervating the dura

    Science.gov (United States)

    2012-01-01

    Background Migraine and other headache disorders affect a large percentage of the population and cause debilitating pain. Activation and sensitization of the trigeminal primary afferent neurons innervating the dura and cerebral vessels is a crucial step in the “headache circuit”. Many dural afferent neurons respond to algesic and inflammatory agents. Given the clear role of the transient receptor potential (TRP) family of channels in both sensing chemical stimulants and mediating inflammatory pain, we investigated the expression of TRP channels in dural afferent neurons. Methods We used two fluorescent tracers to retrogradely label dural afferent neurons in adult mice and quantified the abundance of peptidergic and non-peptidergic neuron populations using calcitonin gene-related peptide immunoreactivity (CGRP-ir) and isolectin B4 (IB4) binding as markers, respectively. Using immunohistochemistry, we compared the expression of TRPV1 and TRPA1 channels in dural afferent neurons with the expression in total trigeminal ganglion (TG) neurons. To examine the distribution of TRPM8 channels, we labeled dural afferent neurons in mice expressing farnesylated enhanced green fluorescent protein (EGFPf) from a TRPM8 locus. We used nearest-neighbor measurement to predict the spatial association between dural afferent neurons and neurons expressing TRPA1 or TRPM8 channels in the TG. Results and conclusions We report that the size of dural afferent neurons is significantly larger than that of total TG neurons and facial skin afferents. Approximately 40% of dural afferent neurons exhibit IB4 binding. Surprisingly, the percentage of dural afferent neurons containing CGRP-ir is significantly lower than those of total TG neurons and facial skin afferents. Both TRPV1 and TRPA1 channels are expressed in dural afferent neurons. Furthermore, nearest-neighbor measurement indicates that TRPA1-expressing neurons are clustered around a subset of dural afferent neurons. Interestingly, TRPM

  7. Direct Thy-1/alphaVbeta3 integrin interaction mediates neuron to astrocyte communication.

    Science.gov (United States)

    Hermosilla, Tamara; Muñoz, Daniel; Herrera-Molina, Rodrigo; Valdivia, Alejandra; Muñoz, Nicolás; Nham, Sang-Uk; Schneider, Pascal; Burridge, Keith; Quest, Andrew F G; Leyton, Lisette

    2008-06-01

    Thy-1 is an abundant neuronal glycoprotein of poorly defined function. We recently provided evidence indicating that Thy-1 clusters a beta3-containing integrin in astrocytes to induce tyrosine phosphorylation, RhoA activation and the formation of focal adhesions and stress fibers. To date, the alpha subunit partner of beta3 integrin in DI TNC1 astrocytes is unknown. Similarly, the ability of neuronal, membrane-bound Thy-1 to trigger astrocyte signaling via integrin engagement remains speculation. Here, evidence that alphav forms an alphavbeta3 heterodimer in DI TNC1 astrocytes was obtained. In neuron-astrocyte association assays, the presence of either anti-alphav or anti-beta3 integrin antibodies reduced cell-cell interaction demonstrating the requirement of both integrin subunits for this association. Moreover, anti-Thy-1 antibodies blocked stimulation of astrocytes by neurons but not the binding of these two cell types. Thus, neuron-astrocyte association involved binding between molecular components in addition to the Thy-1-integrin; however, the signaling events leading to focal adhesion formation in astrocytes depended exclusively on the latter interaction. Additionally, wild-type (RLD) but not mutated (RLE) Thy-1 was shown to directly interact with alphavbeta3 integrin by Surface Plasmon Resonance analysis. This interaction was promoted by divalent cations and was species-independent. Together, these results demonstrate that the alphavbeta3 integrin heterodimer interacts directly with Thy-1 present on neuronal cells to stimulate astrocytes.

  8. LRP1 controls biosynthetic and endocytic trafficking of neuronal prion protein

    DEFF Research Database (Denmark)

    Parkyn, Celia J; Vermeulen, Esmeralda G M; Mootoosamy, Roy C

    2008-01-01

    The trafficking of normal cellular prion protein (PrP(C)) is believed to control its conversion to the altered conformation (designated PrP(Sc)) associated with prion disease. Although anchored to the membrane by means of glycosylphosphatidylinositol (GPI), PrP(C) on neurons is rapidly and consti......The trafficking of normal cellular prion protein (PrP(C)) is believed to control its conversion to the altered conformation (designated PrP(Sc)) associated with prion disease. Although anchored to the membrane by means of glycosylphosphatidylinositol (GPI), PrP(C) on neurons is rapidly...... required for this process. Moreover, sustained inhibition of LRP1 levels by siRNA leads to the accumulation of PrP(C) in biosynthetic compartments, with a concomitant lowering of surface PrP(C), suggesting that LRP1 expedites the trafficking of PrP(C) to the neuronal surface. PrP(C) and LRP1 can be co......-immunoprecipitated from the endoplasmic reticulum in normal neurons. The N-terminal domain of PrP(C) binds to purified human LRP1 with nanomolar affinity, even in the presence of 1 microM of the LRP-specific chaperone, receptor-associated protein (RAP). Taken together, these data argue that LRP1 controls both the surface...

  9. PINK1 is necessary for long term survival and mitochondrial function in human dopaminergic neurons.

    Directory of Open Access Journals (Sweden)

    Alison Wood-Kaczmar

    2008-06-01

    Full Text Available Parkinson's disease (PD is a common age-related neurodegenerative disease and it is critical to develop models which recapitulate the pathogenic process including the effect of the ageing process. Although the pathogenesis of sporadic PD is unknown, the identification of the mendelian genetic factor PINK1 has provided new mechanistic insights. In order to investigate the role of PINK1 in Parkinson's disease, we studied PINK1 loss of function in human and primary mouse neurons. Using RNAi, we created stable PINK1 knockdown in human dopaminergic neurons differentiated from foetal ventral mesencephalon stem cells, as well as in an immortalised human neuroblastoma cell line. We sought to validate our findings in primary neurons derived from a transgenic PINK1 knockout mouse. For the first time we demonstrate an age dependent neurodegenerative phenotype in human and mouse neurons. PINK1 deficiency leads to reduced long-term viability in human neurons, which die via the mitochondrial apoptosis pathway. Human neurons lacking PINK1 demonstrate features of marked oxidative stress with widespread mitochondrial dysfunction and abnormal mitochondrial morphology. We report that PINK1 plays a neuroprotective role in the mitochondria of mammalian neurons, especially against stress such as staurosporine. In addition we provide evidence that cellular compensatory mechanisms such as mitochondrial biogenesis and upregulation of lysosomal degradation pathways occur in PINK1 deficiency. The phenotypic effects of PINK1 loss-of-function described here in mammalian neurons provides mechanistic insight into the age-related degeneration of nigral dopaminergic neurons seen in PD.

  10. Proneural transcription factor Atoh1 drives highly efficient differentiation of human pluripotent stem cells into dopaminergic neurons.

    Science.gov (United States)

    Sagal, Jonathan; Zhan, Xiping; Xu, Jinchong; Tilghman, Jessica; Karuppagounder, Senthilkumar S; Chen, Li; Dawson, Valina L; Dawson, Ted M; Laterra, John; Ying, Mingyao

    2014-08-01

    Human pluripotent stem cells (PSCs) are a promising cell resource for various applications in regenerative medicine. Highly efficient approaches that differentiate human PSCs into functional lineage-specific neurons are critical for modeling neurological disorders and testing potential therapies. Proneural transcription factors are crucial drivers of neuron development and hold promise for driving highly efficient neuronal conversion in PSCs. Here, we study the functions of proneural transcription factor Atoh1 in the neuronal differentiation of PSCs. We show that Atoh1 is induced during the neuronal conversion of PSCs and that ectopic Atoh1 expression is sufficient to drive PSCs into neurons with high efficiency. Atoh1 induction, in combination with cell extrinsic factors, differentiates PSCs into functional dopaminergic (DA) neurons with >80% purity. Atoh1-induced DA neurons recapitulate key biochemical and electrophysiological features of midbrain DA neurons, the degeneration of which is responsible for clinical symptoms in Parkinson's disease (PD). Atoh1-induced DA neurons provide a reliable disease model for studying PD pathogenesis, such as neurotoxin-induced neurodegeneration in PD. Overall, our results determine the role of Atoh1 in regulating neuronal differentiation and neuron subtype specification of human PSCs. Our Atoh1-mediated differentiation approach will enable large-scale applications of PD patient-derived midbrain DA neurons in mechanistic studies and drug screening for both familial and sporadic PD. ©AlphaMed Press.

  11. Bovine Herpes Virus 1 (BHV-1) and Herpes Simplex Virus Type 1 (HSV-1) Promote Survival of Latently Infected Sensory Neurons, in Part by Inhibiting Apoptosis

    Science.gov (United States)

    Jones, Clinton

    2013-01-01

    α-Herpesvirinae subfamily members, including herpes simplex virus type 1 (HSV-1) and bovine herpes virus 1 (BHV-1), initiate infection in mucosal surfaces. BHV-1 and HSV-1 enter sensory neurons by cell-cell spread where a burst of viral gene expression occurs. When compared to non-neuronal cells, viral gene expression is quickly extinguished in sensory neurons resulting in neuronal survival and latency. The HSV-1 latency associated transcript (LAT), which is abundantly expressed in latently infected neurons, inhibits apoptosis, viral transcription, and productive infection, and directly or indirectly enhances reactivation from latency in small animal models. Three anti-apoptosis genes can be substituted for LAT, which will restore wild type levels of reactivation from latency to a LAT null mutant virus. Two small non-coding RNAs encoded by LAT possess anti-apoptosis functions in transfected cells. The BHV-1 latency related RNA (LR-RNA), like LAT, is abundantly expressed during latency. The LR-RNA encodes a protein (ORF2) and two microRNAs that are expressed in certain latently infected neurons. Wild-type expression of LR gene products is required for stress-induced reactivation from latency in cattle. ORF2 has anti-apoptosis functions and interacts with certain cellular transcription factors that stimulate viral transcription and productive infection. ORF2 is predicted to promote survival of infected neurons by inhibiting apoptosis and sequestering cellular transcription factors which stimulate productive infection. In addition, the LR encoded microRNAs inhibit viral transcription and apoptosis. In summary, the ability of BHV-1 and HSV-1 to interfere with apoptosis and productive infection in sensory neurons is crucial for the life-long latency-reactivation cycle in their respective hosts. PMID:25278776

  12. BACE1 Deficiency Causes Abnormal Neuronal Clustering in the Dentate Gyrus

    Directory of Open Access Journals (Sweden)

    Hailong Hou

    2017-07-01

    Full Text Available BACE1 is validated as Alzheimer's β-secretase and a therapeutic target for Alzheimer's disease. In examining BACE1-null mice, we discovered that BACE1 deficiency develops abnormal clusters of immature neurons, forming doublecortin-positive neuroblasts, in the developing dentate gyrus, mainly in the subpial zone (SPZ. Such clusters were rarely observed in wild-type SPZ and not reported in other mouse models. To understand their origins and fates, we examined how neuroblasts in BACE1-null SPZ mature and migrate during early postnatal development. We show that such neuroblasts are destined to form Prox1-positive granule cells in the dentate granule cell layer, and mainly mature to form excitatory neurons, but not inhibitory neurons. Mechanistically, higher levels of reelin potentially contribute to abnormal neurogenesis and timely migration in BACE1-null SPZ. Altogether, we demonstrate that BACE1 is a critical regulator in forming the dentate granule cell layer through timely maturation and migration of SPZ neuroblasts.

  13. Wnt1 from cochlear schwann cells enhances neuronal differentiation of transplanted neural stem cells in a rat spiral ganglion neuron degeneration model.

    Science.gov (United States)

    He, Ya; Zhang, Peng-Zhi; Sun, Dong; Mi, Wen-Juan; Zhang, Xin-Yi; Cui, Yong; Jiang, Xing-Wang; Mao, Xiao-Bo; Qiu, Jian-Hua

    2014-04-01

    Although neural stem cell (NSC) transplantation is widely expected to become a therapy for nervous system degenerative diseases and injuries, the low neuronal differentiation rate of NSCs transplanted into the inner ear is a major obstacle for the successful treatment of spiral ganglion neuron (SGN) degeneration. In this study, we validated whether the local microenvironment influences the neuronal differentiation of transplanted NSCs in the inner ear. Using a rat SGN degeneration model, we demonstrated that transplanted NSCs were more likely to differentiate into microtubule-associated protein 2 (MAP2)-positive neurons in SGN-degenerated cochleae than in control cochleae. Using real-time quantitative PCR and an immunofluorescence assay, we also proved that the expression of Wnt1 (a ligand of Wnt signaling) increases significantly in Schwann cells in the SGN-degenerated cochlea. We further verified that NSC cultures express receptors and signaling components for Wnts. Based on these expression patterns, we hypothesized that Schwann cell-derived Wnt1 and Wnt signaling might be involved in the regulation of the neuronal differentiation of transplanted NSCs. We verified our hypothesis in vitro using a coculture system. We transduced a lentiviral vector expressing Wnt1 into cochlear Schwann cell cultures and cocultured them with NSC cultures. The coculture with Wnt1-expressing Schwann cells resulted in a significant increase in the percentage of NSCs that differentiated into MAP2-positive neurons, whereas this differentiation-enhancing effect was prevented by Dkk1 (an inhibitor of the Wnt signaling pathway). These results suggested that Wnt1 derived from cochlear Schwann cells enhanced the neuronal differentiation of transplanted NSCs through Wnt signaling pathway activation. Alterations of the microenvironment deserve detailed investigation because they may help us to conceive effective strategies to overcome the barrier of the low differentiation rate of transplanted

  14. Scalable control of mounting and attack by Esr1+ neurons in the ventromedial hypothalamus.

    Science.gov (United States)

    Lee, Hyosang; Kim, Dong-Wook; Remedios, Ryan; Anthony, Todd E; Chang, Angela; Madisen, Linda; Zeng, Hongkui; Anderson, David J

    2014-05-29

    Social behaviours, such as aggression or mating, proceed through a series of appetitive and consummatory phases that are associated with increasing levels of arousal. How such escalation is encoded in the brain, and linked to behavioural action selection, remains an unsolved problem in neuroscience. The ventrolateral subdivision of the murine ventromedial hypothalamus (VMHvl) contains neurons whose activity increases during male-male and male-female social encounters. Non-cell-type-specific optogenetic activation of this region elicited attack behaviour, but not mounting. We have identified a subset of VMHvl neurons marked by the oestrogen receptor 1 (Esr1), and investigated their role in male social behaviour. Optogenetic manipulations indicated that Esr1(+) (but not Esr1(-)) neurons are sufficient to initiate attack, and that their activity is continuously required during ongoing agonistic behaviour. Surprisingly, weaker optogenetic activation of these neurons promoted mounting behaviour, rather than attack, towards both males and females, as well as sniffing and close investigation. Increasing photostimulation intensity could promote a transition from close investigation and mounting to attack, within a single social encounter. Importantly, time-resolved optogenetic inhibition experiments revealed requirements for Esr1(+) neurons in both the appetitive (investigative) and the consummatory phases of social interactions. Combined optogenetic activation and calcium imaging experiments in vitro, as well as c-Fos analysis in vivo, indicated that increasing photostimulation intensity increases both the number of active neurons and the average level of activity per neuron. These data suggest that Esr1(+) neurons in VMHvl control the progression of a social encounter from its appetitive through its consummatory phases, in a scalable manner that reflects the number or type of active neurons in the population.

  15. 31 CFR 129.6 - Penalties specified by law.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Penalties specified by law. 129.6 Section 129.6 Money and Finance: Treasury Regulations Relating to Money and Finance PORTFOLIO INVESTMENT SURVEY REPORTING § 129.6 Penalties specified by law. Reporters are advised that the Act provides the...

  16. Reactive oxygen species mediate TNFR1 increase after TRPV1 activation in mouse DRG neurons

    Directory of Open Access Journals (Sweden)

    Westlund Karin N

    2009-06-01

    Full Text Available Abstract Background Transient receptor potential vanilloid subtype 1 (TRPV1 is activated by low pH/protons and is well known to be involved in hyperalgesia during inflammation. Tumor necrosis factor α (TNF-α, a proinflammatory cytokine, is involved in nociceptive responses causing hyperalgesia through TNF receptor type 1 (TNFR1 activation. Reactive oxygen species (ROS production is also prominently increased in inflamed tissue. The present study investigated TNFR1 receptors in primary cultured mouse dorsal root ganglion (DRG neurons after TRPV1 activation and the involvement of ROS. C57BL/6 mice, both TRPV1 knockout and wild type, were used for immunofluorescent and live cell imaging. The L4 and L5 DRGs were dissected bilaterally and cultured overnight. TRPV1 was stimulated with capsaicin or its potent analog, resiniferatoxin. ROS production was measured with live cell imaging and TNFR1 was detected with immunofluorescence in DRG primary cultures. The TRPV1 knockout mice, TRPV1 antagonist, capsazepine, and ROS scavenger, N-tert-Butyl-α-phenylnitrone (PBN, were employed to explore the functional relationship among TRPV1, ROS and TNFR1 in these studies. Results The results demonstrate that TRPV1 activation increases TNFR1 receptors and ROS generation in primary cultures of mouse DRG neurons. Activated increases in TNFR1 receptors and ROS production are absent in TRPV1 deficient mice. The PBN blocks increases in TNFR1 and ROS production induced by capsaicin/resiniferatoxin. Conclusion TRPV1 activation increases TNFR1 in cultured mouse DRG neurons through a ROS signaling pathway, a novel sensitization mechanism in DRG neurons.

  17. Methamphetamine induces heme oxygenase-1 expression in cortical neurons and glia to prevent its toxicity

    International Nuclear Information System (INIS)

    Huang, Y.-N.; Wu, C.-H.; Lin, T.-C.; Wang, J.-Y.

    2009-01-01

    The impairment of cognitive and motor functions in humans and animals caused by methamphetamine (METH) administration underscores the importance of METH toxicity in cortical neurons. The heme oxygenase-1 (HO-1) exerts a cytoprotective effect against various neuronal injures; however, it remains unclear whether HO-1 is involved in METH-induced toxicity. We used primary cortical neuron/glia cocultures to explore the role of HO-1 in METH-induced toxicity. Exposure of cultured cells to various concentrations of METH (0.1, 0.5, 1, 3, 5, and 10 mM) led to cytotoxicity in a concentration-dependent manner. A METH concentration of 5 mM, which caused 50% of neuronal death and glial activation, was chosen for subsequent experiments. RT-PCR and Western blot analysis revealed that METH significantly induced HO-1 mRNA and protein expression, both preceded cell death. Double and triple immunofluorescence staining further identified HO-1-positive cells as activated astrocytes, microglia, and viable neurons, but not dying neurons. Inhibition of the p38 mitogen-activated protein kinase pathway significantly blocked HO-1 induction by METH and aggravated METH neurotoxicity. Inhibition of HO activity using tin protoporphyrine IX significantly reduced HO activity and exacerbated METH neurotoxicity. However, prior induction of HO-1 using cobalt protoporphyrine IX partially protected neurons from METH toxicity. Taken together, our results suggest that induction of HO-1 by METH via the p38 signaling pathway may be protective, albeit insufficient to completely protect cortical neurons from METH toxicity.

  18. Developmental wiring of specific neurons is regulated by RET-1/Nogo-A in Caenorhabditis elegans

    DEFF Research Database (Denmark)

    Torpe, Nanna; Nørgaard, Steffen; Høye, Anette M.

    2017-01-01

    Nogo-A is a membrane-bound protein that functions to inhibit neuronal migration, adhesion, and neurite outgrowth during development. In the mature nervous system, Nogo-A stabilizes neuronal wiring to inhibit neuronal plasticity and regeneration after injury. Here, we show that RET-1, the sole Nog...... present a previously unidentified function for RET-1 in the nervous system of C. elegans.......-A homolog in Caenorhabditis elegans, is required to control developmental wiring of a specific subset of neurons. In ret-1 deletion mutant animals, specific ventral nerve cord axons are misguided where they fail to respect the ventral midline boundary. We found that ret-1 is expressed in multiple neurons...

  19. AP4M1 is abnormally expressed in oxygen-glucose deprived hippocampal neurons.

    Science.gov (United States)

    Zhang, J; Cheng, X Y; Sheng, G Y

    2014-03-20

    AP4M1 mutations have been suggested to be associated with autosomal recessive cerebral palsy syndrome. But the pathogenic mechanism remains uncertain. The purpose of this study is to investigate whether and how AP4M1 expression is changed in injured neurons. Primary cultured hippocampal neurons were prepared for this experiment. They were subjected to oxygen-glucose deprivation (OGD) leading to apoptosis, mimicking brain ischemia. Neuron-specific enolase (NSE) was labeled immunofluorescently to confirm that the purity of neuron was higher than 90%. Real-time PCR and western blotting were performed to measure the gene expression. AP4M1 was labeled with MAP2 or Tau-1 to observe the distribution. We found that the AP4M1 protein levels immediately after the procedure were similar between the OGD group and the sham group. However, down-regulation was observed 12h after the reperfusion, and became more notable at 24h. The real-time PCR showed similar results, except that the down-regulation of mRNA was able to be detected immediately after the OGD. Immunofluorescent labeling revealed AP4M1 distributed in the dendrites of normal neurons, but it redistributed to the axons after the OGD procedure. In conclusion, AP4M1 is not only down-regulated at both the mRNA and protein levels, but also redistributed from dendrites to axons in oxygen-glucose deprived hippocampal neurons. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  20. Nav 1.8-null mice show stimulus-dependent deficits in spinal neuronal activity

    Directory of Open Access Journals (Sweden)

    Wood John N

    2006-02-01

    Full Text Available Abstract Background The voltage gated sodium channel Nav 1.8 has a highly restricted expression pattern to predominantly nociceptive peripheral sensory neurones. Behaviourally Nav 1.8-null mice show an increased acute pain threshold to noxious mechanical pressure and also deficits in inflammatory and visceral, but not neuropathic pain. Here we have made in vivo electrophysiology recordings of dorsal horn neurones in intact anaesthetised Nav 1.8-null mice, in response to a wide range of stimuli to further the understanding of the functional roles of Nav 1.8 in pain transmission from the periphery to the spinal cord. Results Nav 1.8-null mice showed marked deficits in the coding by dorsal horn neurones to mechanical, but not thermal, -evoked responses over the non-noxious and noxious range compared to littermate controls. Additionally, responses evoked to other stimulus modalities were also significantly reduced in Nav 1.8-null mice where the reduction observed to pinch > brush. The occurrence of ongoing spontaneous neuronal activity was significantly less in mice lacking Nav 1.8 compared to control. No difference was observed between groups in the evoked activity to electrical activity of the peripheral receptive field. Conclusion This study demonstrates that deletion of the sodium channel Nav 1.8 results in stimulus-dependent deficits in the dorsal horn neuronal coding to mechanical, but not thermal stimuli applied to the neuronal peripheral receptive field. This implies that Nav 1.8 is either responsible for, or associated with proteins involved in mechanosensation.

  1. Glucose and insulin induce Ca2+ signaling in nesfatin-1 neurons in the hypothalamic paraventricular nucleus.

    Science.gov (United States)

    Gantulga, Darambazar; Maejima, Yuko; Nakata, Masanori; Yada, Toshihiko

    2012-04-20

    Nucleobindin-2 derived nesfatin-1 in the hypothalamic paraventricular nucleus (PVN) plays a role in inhibition of feeding. The neural pathways downstream of PVN nesfatin-1 have been extensively investigated. However, regulation of the PVN nesfatin-1 neurons remains unclear. Since starvation decreases and refeeding stimulates nesfatin-1 expression specifically in the PVN, this study aimed to clarify direct effects of meal-evoked metabolic factors, glucose and insulin, on PVN nesfatin-1 neurons. High glucose (10mM) and insulin (10(-13)M) increased cytosolic calcium concentration ([Ca(2+)](i)) in 55 of 331 (16.6%) and 32 of 249 (12.9%) PVN neurons, respectively. Post [Ca(2+)](i) measurement immunocytochemistry identified that 58.2% of glucose-responsive and 62.5% of insulin-responsive neurons were immunoreactive to nesfatin-1. Furthermore, a fraction of the glucose-responsive nesfatin-1 neurons also responded to insulin, and vice versa. Some of the neurons that responded to neither glucose nor insulin were recruited to [Ca(2+)](i) increases by glucose and insulin in combination. Our data demonstrate that glucose and insulin directly interact with and increase [Ca(2+)](i) in nesfatin-1 neurons in the PVN, and that the nesfatin-1 neuron is the primary target for them in the PVN. The results suggest that high glucose- and insulin-induced activation of PVN nesfatin-1 neurons serves as a mechanism through which meal ingestion stimulates nesfatin-1 neurons in the PVN and thereby produces satiety. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Neuronal human BACE1 knockin induces systemic diabetes in mice.

    Science.gov (United States)

    Plucińska, Kaja; Dekeryte, Ruta; Koss, David; Shearer, Kirsty; Mody, Nimesh; Whitfield, Phillip D; Doherty, Mary K; Mingarelli, Marco; Welch, Andy; Riedel, Gernot; Delibegovic, Mirela; Platt, Bettina

    2016-07-01

    β-Secretase 1 (BACE1) is a key enzyme in Alzheimer's disease pathogenesis that catalyses the amyloidogenic cleavage of amyloid precursor protein (APP). Recently, global Bace1 deletion was shown to protect against diet-induced obesity and diabetes, suggesting that BACE1 is a potential regulator of glucose homeostasis. Here, we investigated whether increased neuronal BACE1 is sufficient to alter systemic glucose metabolism, using a neuron-specific human BACE1 knockin mouse model (PLB4). Glucose homeostasis and adiposity were determined by glucose tolerance tests and EchoMRI, lipid species were measured by quantitative lipidomics, and biochemical and molecular alterations were assessed by western blotting, quantitative PCR and ELISAs. Glucose uptake in the brain and upper body was measured via (18)FDG-PET imaging. Physiological and molecular analyses demonstrated that centrally expressed human BACE1 induced systemic glucose intolerance in mice from 4 months of age onward, alongside a fatty liver phenotype and impaired hepatic glycogen storage. This diabetic phenotype was associated with hypothalamic pathology, i.e. deregulation of the melanocortin system, and advanced endoplasmic reticulum (ER) stress indicated by elevated central C/EBP homologous protein (CHOP) signalling and hyperphosphorylation of its regulator eukaryotic translation initiation factor 2α (eIF2α). In vivo (18)FDG-PET imaging further confirmed brain glucose hypometabolism in these mice; this corresponded with altered neuronal insulin-related signalling, enhanced protein tyrosine phosphatase 1B (PTP1B) and retinol-binding protein 4 (RBP4) levels, along with upregulation of the ribosomal protein and lipid translation machinery. Increased forebrain and plasma lipid accumulation (i.e. ceramides, triacylglycerols, phospholipids) was identified via lipidomics analysis. Our data reveal that neuronal BACE1 is a key regulator of metabolic homeostasis and provide a potential mechanism for the high

  3. 77 FR 9877 - Reporting of Specified Foreign Financial Assets; Correction

    Science.gov (United States)

    2012-02-21

    ... Reporting of Specified Foreign Financial Assets; Correction AGENCY: Internal Revenue Service (IRS). ACTION... the reporting of specified foreign financial assets. FOR FURTHER INFORMATION CONTACT: Joseph S.... List of Subjects in 26 CFR Part 1 Income taxes, Reporting and recordkeeping requirements. PART 1...

  4. Shp-1 dephosphorylates TRPV1 in dorsal root ganglion neurons and alleviates CFA-induced inflammatory pain in rats.

    Science.gov (United States)

    Xiao, Xing; Zhao, Xiao-Tao; Xu, Ling-Chi; Yue, Lu-Peng; Liu, Feng-Yu; Cai, Jie; Liao, Fei-Fei; Kong, Jin-Ge; Xing, Guo-Gang; Yi, Ming; Wan, You

    2015-04-01

    Transient receptor potential vanilloid 1 (TRPV1) receptors are expressed in nociceptive neurons of rat dorsal root ganglions (DRGs) and mediate inflammatory pain. Nonspecific inhibition of protein-tyrosine phosphatases (PTPs) increases the tyrosine phosphorylation of TRPV1 and sensitizes TRPV1. However, less is known about tyrosine phosphorylation's implication in inflammatory pain, compared with that of serine/threonine phosphorylation. Src homology 2 domain-containing tyrosine phosphatase 1 (Shp-1) is a key phosphatase dephosphorylating TRPV1. In this study, we reported that Shp-1 colocalized with and bound to TRPV1 in nociceptive DRG neurons. Shp-1 inhibitors, including sodium stibogluconate and PTP inhibitor III, sensitized TRPV1 in cultured DRG neurons. In naive rats, intrathecal injection of Shp-1 inhibitors increased both TRPV1 and tyrosine-phosphorylated TRPV1 in DRGs and induced thermal hyperalgesia, which was abolished by pretreatment with TRPV1 antagonists capsazepine, BCTC, or AMG9810. Complete Freund's adjuvant (CFA)-induced inflammatory pain in rats significantly increased the expression of Shp-1, TRPV1, and tyrosine-phosphorylated TRPV1, as well as the colocalization of Shp-1 and TRPV1 in DRGs. Intrathecal injection of sodium stibogluconate aggravated CFA-induced inflammatory pain, whereas Shp-1 overexpression in DRG neurons alleviated it. These results suggested that Shp-1 dephosphorylated and inhibited TRPV1 in DRG neurons, contributing to maintain thermal nociceptive thresholds in normal rats, and as a compensatory mechanism, Shp-1 increased in DRGs of rats with CFA-induced inflammatory pain, which was involved in protecting against excessive thermal hyperalgesia.

  5. Th17 Cells Induce Dopaminergic Neuronal Death via LFA-1/ICAM-1 Interaction in a Mouse Model of Parkinson's Disease.

    Science.gov (United States)

    Liu, Zhan; Huang, Yan; Cao, Bei-Bei; Qiu, Yi-Hua; Peng, Yu-Ping

    2017-12-01

    T helper (Th)17 cells, a subset of CD4 + T lymphocytes, have strong pro-inflammatory property and appear to be essential in the pathogenesis of many inflammatory diseases. However, the involvement of Th17 cells in Parkinson's disease (PD) that is characterized by a progressive degeneration of dopaminergic (DAergic) neurons in the nigrostriatal system is unclear. Here, we aimed to demonstrate that Th17 cells infiltrate into the brain parenchyma and induce neuroinflammation and DAergic neuronal death in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)- or 1-methyl-4-phenylpyridinium (MPP + )-induced PD models. Blood-brain barrier (BBB) disruption in the substantia nigra (SN) was assessed by the signal of FITC-labeled albumin that was injected into blood circulation via the ascending aorta. Live cell imaging system was used to observe a direct contact of Th17 cells with neurons by staining these cells using the two adhesion molecules, leukocyte function-associated antigen (LFA)-1 and intercellular adhesion molecule (ICAM)-1, respectively. Th17 cells invaded into the SN where BBB was disrupted in MPTP-induced PD mice. Th17 cells exacerbated DAergic neuronal loss and pro-inflammatory/neurotrophic factor disorders in MPP + -treated ventral mesencephalic (VM) cell cultures. A direct contact of LFA-1-stained Th17 cells with ICAM-1-stained VM neurons was dynamically captured. Either blocking LFA-1 in Th17 cells or blocking ICAM-1 in VM neurons with neutralizing antibodies abolished Th17-induced DAergic neuronal death. These results establish that Th17 cells infiltrate into the brain parenchyma of PD mice through lesioned BBB and exert neurotoxic property by promoting glial activation and importantly by a direct damage to neurons depending on LFA-1/ICAM-1 interaction.

  6. Activation of temperature-sensitive TRPV1-like receptors in ARC POMC neurons reduces food intake.

    Directory of Open Access Journals (Sweden)

    Jae Hoon Jeong

    2018-04-01

    Full Text Available Proopiomelanocortin (POMC neurons in the arcuate nucleus of the hypothalamus (ARC respond to numerous hormonal and neural signals, resulting in changes in food intake. Here, we demonstrate that ARC POMC neurons express capsaicin-sensitive transient receptor potential vanilloid 1 receptor (TRPV1-like receptors. To show expression of TRPV1-like receptors in ARC POMC neurons, we use single-cell reverse transcription-polymerase chain reaction (RT-PCR, immunohistochemistry, electrophysiology, TRPV1 knock-out (KO, and TRPV1-Cre knock-in mice. A small elevation of temperature in the physiological range is enough to depolarize ARC POMC neurons. This depolarization is blocked by the TRPV1 receptor antagonist and by Trpv1 gene knockdown. Capsaicin-induced activation reduces food intake that is abolished by a melanocortin receptor antagonist. To selectively stimulate TRPV1-like receptor-expressing ARC POMC neurons in the ARC, we generate an adeno-associated virus serotype 5 (AAV5 carrying a Cre-dependent channelrhodopsin-2 (ChR2-enhanced yellow fluorescent protein (eYFP expression cassette under the control of the two neuronal POMC enhancers (nPEs. Optogenetic stimulation of TRPV1-like receptor-expressing POMC neurons decreases food intake. Hypothalamic temperature is rapidly elevated and reaches to approximately 39 °C during treadmill running. This elevation is associated with a reduction in food intake. Knockdown of the Trpv1 gene exclusively in ARC POMC neurons blocks the feeding inhibition produced by increased hypothalamic temperature. Taken together, our findings identify a melanocortinergic circuit that links acute elevations in hypothalamic temperature with acute reductions in food intake.

  7. Dysfunction in endoplasmic reticulum-mitochondria crosstalk underlies SIGMAR1 loss of function mediated motor neuron degeneration.

    Science.gov (United States)

    Bernard-Marissal, Nathalie; Médard, Jean-Jacques; Azzedine, Hamid; Chrast, Roman

    2015-04-01

    Mutations in Sigma 1 receptor (SIGMAR1) have been previously identified in patients with amyotrophic lateral sclerosis and disruption of Sigmar1 in mouse leads to locomotor deficits. However, cellular mechanisms underlying motor phenotypes in human and mouse with disturbed SIGMAR1 function have not been described so far. Here we used a combination of in vivo and in vitro approaches to investigate the role of SIGMAR1 in motor neuron biology. Characterization of Sigmar1(-/-) mice revealed that affected animals display locomotor deficits associated with muscle weakness, axonal degeneration and motor neuron loss. Using primary motor neuron cultures, we observed that pharmacological or genetic inactivation of SIGMAR1 led to motor neuron axonal degeneration followed by cell death. Disruption of SIGMAR1 function in motor neurons disturbed endoplasmic reticulum-mitochondria contacts, affected intracellular calcium signalling and was accompanied by activation of endoplasmic reticulum stress and defects in mitochondrial dynamics and transport. These defects were not observed in cultured sensory neurons, highlighting the exacerbated sensitivity of motor neurons to SIGMAR1 function. Interestingly, the inhibition of mitochondrial fission was sufficient to induce mitochondria axonal transport defects as well as axonal degeneration similar to the changes observed after SIGMAR1 inactivation or loss. Intracellular calcium scavenging and endoplasmic reticulum stress inhibition were able to restore mitochondrial function and consequently prevent motor neuron degeneration. These results uncover the cellular mechanisms underlying motor neuron degeneration mediated by loss of SIGMAR1 function and provide therapeutically relevant insight into motor neuronal diseases. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Nod-like receptor protein 1 inflammasome mediates neuron injury under high glucose.

    Science.gov (United States)

    Meng, Xian-Fang; Wang, Xiao-Lan; Tian, Xiu-Juan; Yang, Zhi-Hua; Chu, Guang-Pin; Zhang, Jing; Li, Man; Shi, Jing; Zhang, Chun

    2014-04-01

    Diabetic encephalopathy is one of the most common complications of diabetes. Inflammatory events during diabetes may be an important mechanism of diabetic encephalopathy. Inflammasome is a multiprotein complex consisting of Nod-like receptor proteins (NLRPs), apoptosis-associated speck-like protein (ASC), and caspase 1 or 5, which functions to switch on the inflammatory process and the release of inflammatory factors. The present study hypothesized that the formation and activation of NLRP1 inflammasome turns on neuroinflammation and neuron injury during hyperglycemia. The results demonstrated that the levels of interleukin-1 beta (IL-1β) were increased in the cortex of streptozocin (STZ)-induced diabetic rats. The levels of mature IL-1β and IL-18 were also elevated in culture medium of neurons treated with high glucose (50 mM). The expression of three essential components of the NLRP1 inflammasome complex, namely, NLRP1, ASC, and caspase 1, was also upregulated in vivo and in vitro under high glucose. Silencing the ASC gene prevented the caspase-1 activation, and inhibiting caspase 1 activity blocked hyperglycemia-induced release of inflammatory factors and neuron injury. Moreover, we found that pannexin 1 mediated the actvitation of NLRP1 inflammasome under high glucose. These results suggest that hyperglycemia induces neuroinflammation through activation of NLRP1 inflammasome, which represents a novel mechanism of diabetes-associated neuron injury.

  9. Stalling for Time: It's Not the Magnitude, but the Way Neurons Fire that Matters.

    Science.gov (United States)

    Scott, Stephen H

    2017-07-05

    In this issue of Neuron, Stavisky et al. (2017) demonstrate that visual feedback in M1 during reaching initially reflects a specific pattern of neural activity that does not generate motor output and then is altered to a pattern that does generate motor output. This switch likely provides time for the motor system to consider various behavioral factors when specifying the appropriate motor response during voluntary motor actions. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Activation of Six1 Expression in Vertebrate Sensory Neurons.

    Directory of Open Access Journals (Sweden)

    Shigeru Sato

    Full Text Available SIX1 homeodomain protein is one of the essential key regulators of sensory organ development. Six1-deficient mice lack the olfactory epithelium, vomeronasal organs, cochlea, vestibule and vestibuloacoustic ganglion, and also show poor neural differentiation in the distal part of the cranial ganglia. Simultaneous loss of both Six1 and Six4 leads to additional abnormalities such as small trigeminal ganglion and abnormal dorsal root ganglia (DRG. The aim of this study was to understand the molecular mechanism that controls Six1 expression in sensory organs, particularly in the trigeminal ganglion and DRG. To this end, we focused on the sensory ganglia-specific Six1 enhancer (Six1-8 conserved between chick and mouse. In vivo reporter assays using both animals identified an important core region comprising binding consensus sequences for several transcription factors including nuclear hormone receptors, TCF/LEF, SMAD, POU homeodomain and basic-helix-loop-helix proteins. The results provided information on upstream factors and signals potentially relevant to Six1 regulation in sensory neurons. We also report the establishment of a new transgenic mouse line (mSix1-8-NLSCre that expresses Cre recombinase under the control of mouse Six1-8. Cre-mediated recombination was detected specifically in ISL1/2-positive sensory neurons of Six1-positive cranial sensory ganglia and DRG. The unique features of the mSix1-8-NLSCre line are the absence of Cre-mediated recombination in SOX10-positive glial cells and central nervous system and ability to induce recombination in a subset of neurons derived from the olfactory placode/epithelium. This mouse model can be potentially used to advance research on sensory development.

  11. HSPB1 mutations causing hereditary neuropathy in humans disrupt non-cell autonomous protection of motor neurons.

    Science.gov (United States)

    Heilman, Patrick L; Song, SungWon; Miranda, Carlos J; Meyer, Kathrin; Srivastava, Amit K; Knapp, Amy; Wier, Christopher G; Kaspar, Brian K; Kolb, Stephen J

    2017-11-01

    Heat shock protein beta-1 (HSPB1), is a ubiquitously expressed, multifunctional protein chaperone. Mutations in HSPB1 result in the development of a late-onset, distal hereditary motor neuropathy type II (dHMN) and axonal Charcot-Marie Tooth disease with sensory involvement (CMT2F). The functional consequences of HSPB1 mutations associated with hereditary neuropathy are unknown. HSPB1 also displays neuroprotective properties in many neuronal disease models, including the motor neuron disease amyotrophic lateral sclerosis (ALS). HSPB1 is upregulated in SOD1-ALS animal models during disease progression, predominately in glial cells. Glial cells are known to contribute to motor neuron loss in ALS through a non-cell autonomous mechanism. In this study, we examined the non-cell autonomous role of wild type and mutant HSPB1 in an astrocyte-motor neuron co-culture model system of ALS. Astrocyte-specific overexpression of wild type HSPB1 was sufficient to attenuate SOD1(G93A) astrocyte-mediated toxicity in motor neurons, whereas, overexpression of mutHSPB1 failed to ameliorate motor neuron toxicity. Expression of a phosphomimetic HSPB1 mutant in SOD1(G93A) astrocytes also reduced toxicity to motor neurons, suggesting that phosphorylation may contribute to HSPB1 mediated-neuroprotection. These data provide evidence that astrocytic HSPB1 expression may play a central role in motor neuron health and maintenance. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. The Effects of IGF-1 on Trk Expressing DRG Neurons with HIV-gp120- Induced Neurotoxicity.

    Science.gov (United States)

    Li, Hao; Liu, Zhen; Chi, Heng; Bi, Yanwen; Song, Lijun; Liu, Huaxiang

    2016-01-01

    HIV envelope glycoprotein gp120 is the main protein that causes HIVassociated sensory neuropathy. However, the underlying mechanisms of gp120-induced neurotoxicity are still unclear. There are lack effective treatments for relieving HIV-related neuropathic symptoms caused by gp120-induced neurotoxicity. In the present study, tyrosine kinase receptor (Trk)A, TrkB, and TrkC expression in primary cultured dorsal root ganglion (DRG) neurons with gp120-induced neurotoxicity was investigated. The effects of IGF-1 on distinct Trk-positive DRG neurons with gp120-induced neurotoxicity were also determined. The results showed that gp120 not only dose-dependently induced DRG neuronal apoptosis and inhibited neuronal survival and neurite outgrowth, but also decreased distinct Trk expression levels. IGF-1 rescued DRG neurons from apoptosis and improved neuronal survival of gp120 neurotoxic DRG neurons in vitro. IGF-1 also improved TrkA and TrkB, but not TrkC, expression in gp120 neurotoxic conditions. The effects of IGF-1 could be blocked by preincubation with the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. These results suggested that gp120 may have a wide range of neurotoxicity on different subpopulations of DRG neurons, while IGF-1 might only relieve some subpopulations of DRG neurons with gp120-induced neurotoxicity. These data provide novel information of mechanisms of gp120 neurotoxicity on primary sensory neurons and the potential therapeutic effects of IGF-1 on gp120-induced neurotoxicity.

  13. Sphingosine-1-Phosphate and the S1P3 Receptor Initiate Neuronal Retraction via RhoA/ROCK Associated with CRMP2 Phosphorylation

    Science.gov (United States)

    Quarta, Serena; Camprubí-Robles, Maria; Schweigreiter, Rüdiger; Matusica, Dusan; Haberberger, Rainer V.; Proia, Richard L.; Bandtlow, Christine E.; Ferrer-Montiel, Antonio; Kress, Michaela

    2017-01-01

    The bioactive lipid sphingosine-1-phosphate (S1P) is an important regulator in the nervous system. Here, we explored the role of S1P and its receptors in vitro and in preclinical models of peripheral nerve regeneration. Adult sensory neurons and motor neuron-like cells were exposed to S1P in an in vitro assay, and virtually all neurons responded with a rapid retraction of neurites and growth cone collapse which were associated with RhoA and ROCK activation. The S1P1 receptor agonist SEW2871 neither activated RhoA or neurite retraction, nor was S1P-induced neurite retraction mitigated in S1P1-deficient neurons. Depletion of S1P3 receptors however resulted in a dramatic inhibition of S1P-induced neurite retraction and was on the contrary associated with a significant elongation of neuronal processes in response to S1P. Opposing responses to S1P could be observed in the same neuron population, where S1P could activate S1P1 receptors to stimulate elongation or S1P3 receptors and retraction. S1P was, for the first time in sensory neurons, linked to the phosphorylation of collapsin response-mediated protein-2 (CRMP2), which was inhibited by ROCK inhibition. The improved sensory recovery after crush injury further supported the relevance of a critical role for S1P and receptors in fine-tuning axonal outgrowth in peripheral neurons. PMID:29066950

  14. Neuronal expression of glucosylceramide synthase in central nervous system regulates body weight and energy homeostasis.

    Science.gov (United States)

    Nordström, Viola; Willershäuser, Monja; Herzer, Silke; Rozman, Jan; von Bohlen Und Halbach, Oliver; Meldner, Sascha; Rothermel, Ulrike; Kaden, Sylvia; Roth, Fabian C; Waldeck, Clemens; Gretz, Norbert; de Angelis, Martin Hrabě; Draguhn, Andreas; Klingenspor, Martin; Gröne, Hermann-Josef; Jennemann, Richard

    2013-01-01

    Hypothalamic neurons are main regulators of energy homeostasis. Neuronal function essentially depends on plasma membrane-located gangliosides. The present work demonstrates that hypothalamic integration of metabolic signals requires neuronal expression of glucosylceramide synthase (GCS; UDP-glucose:ceramide glucosyltransferase). As a major mechanism of central nervous system (CNS) metabolic control, we demonstrate that GCS-derived gangliosides interacting with leptin receptors (ObR) in the neuronal membrane modulate leptin-stimulated formation of signaling metabolites in hypothalamic neurons. Furthermore, ganglioside-depleted hypothalamic neurons fail to adapt their activity (c-Fos) in response to alterations in peripheral energy signals. Consequently, mice with inducible forebrain neuron-specific deletion of the UDP-glucose:ceramide glucosyltransferase gene (Ugcg) display obesity, hypothermia, and lower sympathetic activity. Recombinant adeno-associated virus (rAAV)-mediated Ugcg delivery to the arcuate nucleus (Arc) significantly ameliorated obesity, specifying gangliosides as seminal components for hypothalamic regulation of body energy homeostasis.

  15. Alpha2delta-1 in SF1+ Neurons of the Ventromedial Hypothalamus Is an Essential Regulator of Glucose and Lipid Homeostasis.

    Science.gov (United States)

    Felsted, Jennifer A; Chien, Cheng-Hao; Wang, Dongqing; Panessiti, Micaella; Ameroso, Dominique; Greenberg, Andrew; Feng, Guoping; Kong, Dong; Rios, Maribel

    2017-12-05

    The central mechanisms controlling glucose and lipid homeostasis are inadequately understood. We show that α2δ-1 is an essential regulator of glucose and lipid balance, acting in steroidogenic factor-1 (SF1) neurons of the ventromedial hypothalamus (VMH). These effects are body weight independent and involve regulation of SF1 + neuronal activity and sympathetic output to metabolic tissues. Accordingly, mice with α2δ-1 deletion in SF1 neurons exhibit glucose intolerance, altered lipolysis, and decreased cholesterol content in adipose tissue despite normal energy balance regulation. Profound reductions in the firing rate of SF1 neurons, decreased sympathetic output, and elevated circulating levels of serotonin are associated with these alterations. Normal calcium currents but reduced excitatory postsynaptic currents in mutant SF1 neurons implicate α2δ-1 in the promotion of excitatory synaptogenesis separate from its canonical role as a calcium channel subunit. Collectively, these findings identify an essential mechanism that regulates VMH neuronal activity and glycemic and lipid control and may be a target for tackling metabolic disease. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  16. Alpha2delta-1 in SF1+ Neurons of the Ventromedial Hypothalamus Is an Essential Regulator of Glucose and Lipid Homeostasis

    Directory of Open Access Journals (Sweden)

    Jennifer A. Felsted

    2017-12-01

    Full Text Available Summary: The central mechanisms controlling glucose and lipid homeostasis are inadequately understood. We show that α2δ-1 is an essential regulator of glucose and lipid balance, acting in steroidogenic factor-1 (SF1 neurons of the ventromedial hypothalamus (VMH. These effects are body weight independent and involve regulation of SF1+ neuronal activity and sympathetic output to metabolic tissues. Accordingly, mice with α2δ-1 deletion in SF1 neurons exhibit glucose intolerance, altered lipolysis, and decreased cholesterol content in adipose tissue despite normal energy balance regulation. Profound reductions in the firing rate of SF1 neurons, decreased sympathetic output, and elevated circulating levels of serotonin are associated with these alterations. Normal calcium currents but reduced excitatory postsynaptic currents in mutant SF1 neurons implicate α2δ-1 in the promotion of excitatory synaptogenesis separate from its canonical role as a calcium channel subunit. Collectively, these findings identify an essential mechanism that regulates VMH neuronal activity and glycemic and lipid control and may be a target for tackling metabolic disease. : Felsted et al. show a required role of the calcium channel subunit and thrombospondin receptor α2δ-1 in regulating glucose and lipid homeostasis in the ventromedial hypothalamus (VMH. These effects are caused by regulation of SF1+ neuronal activity in the VMH through non-canonical mechanisms and concomitant influences on sympathetic output. Keywords: diabetes, VMH, hypothalamus, glucose, norepinephrine, serotonin, excitability, lipid, SF1

  17. Cognitive Deficits Associated with Nav1.1 Alterations: Involvement of Neuronal Firing Dynamics and Oscillations.

    Directory of Open Access Journals (Sweden)

    Alex C Bender

    Full Text Available Brain oscillations play a critical role in information processing and may, therefore, be essential to uncovering the mechanisms of cognitive impairment in neurological disease. In Dravet syndrome (DS, a mutation in SCN1A, coding for the voltage-gated sodium channel Nav1.1, is associated with severe cognitive impairment and seizures. While seizure frequency and severity do not correlate with the extent of impairment, the slowing of brain rhythms may be involved. Here we investigate the role of Nav1.1 on brain rhythms and cognition using RNA interference. We demonstrate that knockdown of Nav1.1 impairs fast- and burst-firing properties of neurons in the medial septum in vivo. The proportion of neurons that fired phase-locked to hippocampal theta oscillations was reduced, and medial septal regulation of theta rhythm was disrupted. During a working memory task, this deficit was characterized by a decrease in theta frequency and was negatively correlated with performance. These findings suggest a fundamental role for Nav1.1 in facilitating fast-firing properties in neurons, highlight the importance of precise temporal control of theta frequency for working memory, and imply that Nav1.1 deficits may disrupt information processing in DS via a dysregulation of brain rhythms.

  18. ERK1/2 mediates glucose-regulated POMC gene expression in hypothalamic neurons.

    Science.gov (United States)

    Zhang, Juan; Zhou, Yunting; Chen, Cheng; Yu, Feiyuan; Wang, Yun; Gu, Jiang; Ma, Lian; Ho, Guyu

    2015-04-01

    Hypothalamic glucose-sensing neurons regulate the expression of genes encoding feeding-related neuropetides POMC, AgRP, and NPY - the key components governing metabolic homeostasis. AMP-activated protein kinase (AMPK) is postulated to be the molecular mediator relaying glucose signals to regulate the expression of these neuropeptides. Whether other signaling mediator(s) plays a role is not clear. In this study, we investigated the role of ERK1/2 using primary hypothalamic neurons as the model system. The primary neurons were differentiated from hypothalamic progenitor cells. The differentiated neurons possessed the characteristic neuronal cell morphology and expressed neuronal post-mitotic markers as well as leptin-regulated orexigenic POMC and anorexigenic AgRP/NPY genes. Treatment of cells with glucose dose-dependently increased POMC and decreased AgRP/NPY expression with a concurrent suppression of AMPK phosphorylation. In addition, glucose treatment dose-dependently increased the ERK1/2 phosphorylation. Blockade of ERK1/2 activity with its specific inhibitor PD98059 partially (approximately 50%) abolished glucose-induced POMC expression, but had little effect on AgRP/NPY expression. Conversely, blockade of AMPK activity with its specific inhibitor produced a partial (approximately 50%) reversion of low-glucose-suppressed POMC expression, but almost completely blunted the low-glucose-induced AgRP/NPY expression. The results indicate that ERK1/2 mediated POMC but not AgRP/NPY expression. Confirming the in vitro findings, i.c.v. administration of PD98059 in rats similarly attenuated glucose-induced POMC expression in the hypothalamus, but again had little effect on AgRP/NPY expression. The results are indicative of a novel role of ERK1/2 in glucose-regulated POMC expression and offer new mechanistic insights into hypothalamic glucose sensing. © 2015 Society for Endocrinology.

  19. Fluoxetine protects against IL-1β-induced neuronal apoptosis via downregulation of p53.

    Science.gov (United States)

    Shan, Han; Bian, Yaqi; Shu, Zhaoma; Zhang, Linxia; Zhu, Jialei; Ding, Jianhua; Lu, Ming; Xiao, Ming; Hu, Gang

    2016-08-01

    Fluoxetine, a selective serotonin reuptake inhibitor, exerts neuroprotective effects in a variety of neurological diseases including stroke, but the underlying mechanism remains obscure. In the present study, we addressed the molecular events in fluoxetine against ischemia/reperfusion-induced acute neuronal injury and inflammation-induced neuronal apoptosis. We showed that treatment of fluoxetine (40 mg/kg, i.p.) with twice injections at 1 h and 12 h after transient middle cerebral artery occlusion (tMCAO) respectively alleviated neurological deficits and neuronal apoptosis in a mouse ischemic stroke model, accompanied by inhibiting interleukin-1β (IL-1β), Bax and p53 expression and upregulating anti-apoptotic protein Bcl-2 level. We next mimicked neuroinflammation in ischemic stroke with IL-1β in primary cultured cortical neurons and found that pretreatment with fluoxetine (1 μM) prevented IL-1β-induced neuronal apoptosis and upregulation of p53 expression. Furthermore, we demonstrated that p53 overexpression in N2a cell line abolished the anti-apoptotic effect of fluoxetine, indicating that p53 downregulation is required for the protective role of fluoxetine in IL-1β-induced neuronal apoptosis. Fluoxetine downregulating p53 expression could be mimicked by SB203580, a specific inhibitor of p38, but blocked by anisomycin, a p38 activator. Collectively, our findings have revealed that fluoxetine protects against IL-1β-induced neuronal apoptosis via p38-p53 dependent pathway, which give us an insight into the potential of fluoxetine in terms of opening up novel therapeutic avenues for neurological diseases including stroke. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Infection and Transport of Herpes Simplex Virus Type 1 in Neurons: Role of the Cytoskeleton

    Science.gov (United States)

    2018-01-01

    Herpes simplex virus type 1 (HSV-1) is a neuroinvasive human pathogen that has the ability to infect and replicate within epithelial cells and neurons and establish a life-long latent infection in sensory neurons. HSV-1 depends on the host cellular cytoskeleton for entry, replication, and exit. Therefore, HSV-1 has adapted mechanisms to promote its survival by exploiting the microtubule and actin cytoskeletons to direct its active transport, infection, and spread between neurons and epithelial cells during primary and recurrent infections. This review will focus on the currently known mechanisms utilized by HSV-1 to harness the neuronal cytoskeleton, molecular motors, and the secretory and exocytic pathways for efficient virus entry, axonal transport, replication, assembly, and exit from the distinct functional compartments (cell body and axon) of the highly polarized sensory neurons. PMID:29473915

  1. Function and coding in the blowfly H1 neuron during naturalistic optic flow

    NARCIS (Netherlands)

    Hateren, J.H. van; Kern, R.; Schwerdtfeger, G.; Egelhaaf, M.

    2005-01-01

    Naturalistic stimuli, reconstructed from measured eye movements of flying blowflies, were replayed on a panoramic stimulus device. The directional movement-sensitive H1 neuron was recorded from blowflies watching these stimuli. The response of the H1 neuron is dominated by the response to fast

  2. Effects of Forskolin on Trefoil factor 1 expression in cultured ventral mesencephalic dopaminergic neurons

    DEFF Research Database (Denmark)

    Jensen, Pia; Ducray, A D; Widmer, H R

    2015-01-01

    shown that TFF1 is expressed in developing and adult rat ventral mesencephalic tyrosine hydroxylase-immunoreactive (TH-ir) dopaminergic neurons. Here, we investigated the expression of TFF1 in rat ventral mesencephalic dopaminergic neurons (embryonic day 14) grown in culture for 5, 7 or 10days......, suggesting that Forskolin induced TFF1 expression through diverse signaling pathways. In conclusion, distinct populations of cultured dopaminergic neurons express TFF1, and their numbers can be increased by factors known to influence survival and differentiation of dopaminergic cells....... to neuronal cells, and the percentage of TH/TFF1 co-expressing cells was increased to the same extent in GDNF and Forskolin-treated cultures (4-fold) as compared to controls. Interestingly, the combination of GDNF and Forskolin resulted in a significantly increased co-expression (8-fold) of TH/TFF1, which...

  3. Thy1.2 YFP-16 transgenic mouse labels a subset of large-diameter sensory neurons that lack TRPV1 expression.

    Directory of Open Access Journals (Sweden)

    Thomas E Taylor-Clark

    Full Text Available The Thy1.2 YFP-16 mouse expresses yellow fluorescent protein (YFP in specific subsets of peripheral and central neurons. The original characterization of this model suggested that YFP was expressed in all sensory neurons, and this model has been subsequently used to study sensory nerve structure and function. Here, we have characterized the expression of YFP in the sensory ganglia (DRG, trigeminal and vagal of the Thy1.2 YFP-16 mouse, using biochemical, functional and anatomical analyses. Despite previous reports, we found that YFP was only expressed in approximately half of DRG and trigeminal neurons and less than 10% of vagal neurons. YFP-expression was only found in medium and large-diameter neurons that expressed neurofilament but not TRPV1. YFP-expressing neurons failed to respond to selective agonists for TRPV1, P2X(2/3 and TRPM8 channels in Ca2+ imaging assays. Confocal analysis of glabrous skin, hairy skin of the back and ear and skeletal muscle indicated that YFP was expressed in some peripheral terminals with structures consistent with their presumed non-nociceptive nature. In summary, the Thy1.2 YFP-16 mouse expresses robust YFP expression in only a subset of sensory neurons. But this mouse model is not suitable for the study of nociceptive nerves or the function of such nerves in pain and neuropathies.

  4. VPS35 regulates developing mouse hippocampal neuronal morphogenesis by promoting retrograde trafficking of BACE1

    Directory of Open Access Journals (Sweden)

    Chun-Lei Wang

    2012-10-01

    VPS35, a major component of the retromer, plays an important role in the selective endosome-to-Golgi retrieval of membrane proteins. Dysfunction of retromer is a risk factor for neurodegenerative disorders, but its function in developing mouse brain remains poorly understood. Here we provide evidence for VPS35 promoting dendritic growth and maturation, and axonal protein transport in developing mouse hippocampal neurons. Embryonic hippocampal CA1 neurons suppressing Vps35 expression by in utero electroporation of its micro RNAs displayed shortened apical dendrites, reduced dendritic spines, and swollen commissural axons in the neonatal stage, those deficits reflecting a defective protein transport/trafficking in developing mouse neurons. Further mechanistic studies showed that Vps35 depletion in neurons resulted in an impaired retrograde trafficking of BACE11-secretase and altered BACE1 distribution. Suppression of BACE1 expression in CA1 neurons partially rescued both dendritic and axonal deficits induced by Vps35-deficiency. These results thus demonstrate that BACE1 acts as a critical cargo of retromer in vitro and in vivo, and suggest that VPS35 plays an essential role in regulating apical dendritic maturation and in preventing axonal spheroid formation in developing hippocampal neurons.

  5. Transcription factors Foxa1 and Foxa2 are required for adult dopamine neurons maintenance

    Directory of Open Access Journals (Sweden)

    Andrii eDomanskyi

    2014-09-01

    Full Text Available The proteins Foxa1 and Foxa2 belong to the forkhead family of transcription factors and are involved in the development of several tissues, including liver, pancreas, lung, prostate, and the neural system. Both Foxa1 and Foxa2 are also crucial for the specification and differentiation of dopamine (DA neurons during embryonic development, while about 30% of mice with an embryonic deletion of a single allele of the Foxa2 gene exhibit an age-related asymmetric loss of DA neurons and develop locomotor symptoms resembling Parkinson’s disease (PD. Notably, both Foxa1 and Foxa2 factors continue to be expressed in the adult dopamine system. To directly assess their functions selectively in adult DA neurons, we induced genetic deletions of Foxa1/2 transcription factors in mice using a tamoxifen inducible tissue-specific CreERT2 recombinase expressed under control of the dopamine transporter (DAT promoter (DATCreERT2. The conditional DA neurons-specific ablation of both genes, but not of Foxa2 alone, in early adulthood, caused a decline of striatal dopamine and its metabolites, along with locomotor deficits. At early pre-symptomatic stages, we observed a decline in aldehyde dehydrogenase family 1, subfamily A1 (Aldh1a1 protein expression in DA neurons. Further analyses revealed a decline of aromatic amino acid decarboxylase (AADC and a complete loss of DAT expression in these neurons. These molecular changes ultimately led to a reduction of DA neuron numbers in the substantia nigra pars compacta (SNpc of aged cFoxa1/2-/- mice, resembling the progressive course of PD in humans. Altogether, in this study, we address the molecular, cellular and functional role of both Foxa1 and Foxa2 factors in the maintenance of the adult dopamine system which may help to find better approaches for PD treatment.

  6. Insulin and Leptin Signaling Interact in the Mouse Kiss1 Neuron during the Peripubertal Period.

    Directory of Open Access Journals (Sweden)

    Xiaoliang Qiu

    Full Text Available Reproduction requires adequate energy stores for parents and offspring to survive. Kiss1 neurons, which are essential for fertility, have the potential to serve as the central sensors of metabolic factors that signal to the reproductive axis the presence of stored calories. Paradoxically, obesity is often accompanied by infertility. Despite excess circulating levels of insulin and leptin, obese individuals exhibit resistance to both metabolic factors in many neuron types. Thus, resistance to insulin or leptin in Kiss1 neurons could lead to infertility. Single deletion of the receptors for either insulin or the adipokine leptin from Kiss1 neurons does not impair adult reproductive dysfunction. However, insulin and leptin signaling pathways may interact in such a way as to obscure their individual functions. We hypothesized that in the presence of genetic or obesity-induced concurrent insulin and leptin resistance, Kiss1 neurons would be unable to maintain reproductive function. We therefore induced a chronic hyperinsulinemic and hyperleptinemic state in mice lacking insulin receptors in Kiss1 neurons through high fat feeding and examined the impact on fertility. In an additional, genetic model, we ablated both leptin and insulin signaling in Kiss1 neurons (IR/LepRKiss mice. Counter to our hypothesis, we found that the addition of leptin insensitivity did not alter the reproductive phenotype of IRKiss mice. We also found that weight gain, body composition, glucose and insulin tolerance were normal in mice of both genders. Nonetheless, leptin and insulin receptor deletion altered pubertal timing as well as LH and FSH levels in mid-puberty in a reciprocal manner. Our results confirm that Kiss1 neurons do not directly mediate the critical role that insulin and leptin play in reproduction. However, during puberty kisspeptin neurons may experience a critical window of susceptibility to the influence of metabolic factors that can modify the onset of

  7. U1 snRNP Alteration and Neuronal Cell Cycle Reentry in Alzheimer Disease

    Directory of Open Access Journals (Sweden)

    Bing Bai

    2018-03-01

    Full Text Available The aberrancy of U1 small nuclear ribonucleoprotein (snRNP complex and RNA splicing has been demonstrated in Alzheimer’s disease (AD. Importantly, the U1 proteopathy is AD-specific, widespread and early-occurring, thus providing a very unique clue to the AD pathogenesis. The prominent feature of U1 histopathology is its nuclear depletion and redistribution in the neuronal cytoplasm. According to the preliminary data, the initial U1 cytoplasmic distribution pattern is similar to the subcellular translocation of the spliceosome in cells undergoing mitosis. This implies that the U1 mislocalization might reflect the neuronal cell cycle-reentry (CCR which has been extensively evidenced in AD brains. The CCR phenomenon explains the major molecular and cellular events in AD brains, such as Tau and amyloid precursor protein (APP phosphorylation, and the possible neuronal death through mitotic catastrophe (MC. Furthermore, the CCR might be mechanistically linked to inflammation, a critical factor in the AD etiology according to the genetic evidence. Therefore, the discovery of U1 aberrancy might strengthen the involvement of CCR in the AD neuronal degeneration.

  8. Cre-expressing neurons in the cortical white matter of Ntsr1-Cre GN220 mice.

    Science.gov (United States)

    Sundberg, Sofie C; Granseth, Björn

    2018-03-23

    Genetically modified mouse strains that express Cre-recombinase in specific neuronal sub-populations have become widely used tools for investigating neuronal function. The Ntsr1-Cre GN220 mouse expresses this enzyme in corticothalamic neurons in layer 6 of cerebral cortex. We observed that about 7% of Cre-expressing cells in the primary visual cortex are found within the white matter bordering layer 6. By using the immunohistochemical marker for layer 6 neurons, Forkhead box protein 2 (FoxP2), and fluorescently conjugated latex beads injected into the dorsal lateral geniculate nucleus, we show that about half of these cells are similar to and could belong to the layer 6 corticothalamic neuron population. The other half seems to be a distinct white matter (WM) neuron sub-population that we estimate to constitute 2-4% of the total cortical Cre-expressing population. Staining for the neuronal marker Neuronal nuclei (NeuN) revealed that about 15-40% of WM neurons are Cre-expressing. Thus, the potential contribution from WM neurons needs to be considered when interpreting the results from experiments using the Ntsr1-Cre GN220 mouse for investigating corticothalamic neuronal function. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. TRPA1 is functionally expressed primarily by IB4-binding, non-peptidergic mouse and rat sensory neurons.

    Directory of Open Access Journals (Sweden)

    Marie E Barabas

    Full Text Available Subpopulations of somatosensory neurons are characterized by functional properties and expression of receptor proteins and surface markers. CGRP expression and IB4-binding are commonly used to define peptidergic and non-peptidergic subpopulations. TRPA1 is a polymodal, plasma membrane ion channel that contributes to mechanical and cold hypersensitivity during tissue injury, making it a key target for pain therapeutics. Some studies have shown that TRPA1 is predominantly expressed by peptidergic sensory neurons, but others indicate that TRPA1 is expressed extensively within non-peptidergic, IB4-binding neurons. We used FURA-2 calcium imaging to define the functional distribution of TRPA1 among peptidergic and non-peptidergic adult mouse (C57BL/6J DRG neurons. Approximately 80% of all small-diameter (<27 µm neurons from lumbar 1-6 DRGs that responded to TRPA1 agonists allyl isothiocyanate (AITC; 79% or cinnamaldehyde (84% were IB4-positive. Retrograde labeling via plantar hind paw injection of WGA-Alexafluor594 showed similarly that most (81% cutaneous neurons responding to TRPA1 agonists were IB4-positive. Additionally, we cultured DRG neurons from a novel CGRP-GFP mouse where GFP expression is driven by the CGRPα promoter, enabling identification of CGRP-expressing live neurons. Interestingly, 78% of TRPA1-responsive neurons were CGRP-negative. Co-labeling with IB4 revealed that the majority (66% of TRPA1 agonist responders were IB4-positive but CGRP-negative. Among TRPA1-null DRGs, few small neurons (2-4% responded to either TRPA1 agonist, indicating that both cinnamaldehyde and AITC specifically target TRPA1. Additionally, few large neurons (≥27 µm diameter responded to AITC (6% or cinnamaldehyde (4%, confirming that most large-diameter somata lack functional TRPA1. Comparison of mouse and rat DRGs showed that the majority of TRPA1-responsive neurons in both species were IB4-positive. Together, these data demonstrate that TRPA1 is

  10. TRPA1 Is Functionally Expressed Primarily by IB4-Binding, Non-Peptidergic Mouse and Rat Sensory Neurons

    Science.gov (United States)

    Stucky, Cheryl L.

    2012-01-01

    Subpopulations of somatosensory neurons are characterized by functional properties and expression of receptor proteins and surface markers. CGRP expression and IB4-binding are commonly used to define peptidergic and non-peptidergic subpopulations. TRPA1 is a polymodal, plasma membrane ion channel that contributes to mechanical and cold hypersensitivity during tissue injury, making it a key target for pain therapeutics. Some studies have shown that TRPA1 is predominantly expressed by peptidergic sensory neurons, but others indicate that TRPA1 is expressed extensively within non-peptidergic, IB4-binding neurons. We used FURA-2 calcium imaging to define the functional distribution of TRPA1 among peptidergic and non-peptidergic adult mouse (C57BL/6J) DRG neurons. Approximately 80% of all small-diameter (neurons from lumbar 1–6 DRGs that responded to TRPA1 agonists allyl isothiocyanate (AITC; 79%) or cinnamaldehyde (84%) were IB4-positive. Retrograde labeling via plantar hind paw injection of WGA-Alexafluor594 showed similarly that most (81%) cutaneous neurons responding to TRPA1 agonists were IB4-positive. Additionally, we cultured DRG neurons from a novel CGRP-GFP mouse where GFP expression is driven by the CGRPα promoter, enabling identification of CGRP-expressing live neurons. Interestingly, 78% of TRPA1-responsive neurons were CGRP-negative. Co-labeling with IB4 revealed that the majority (66%) of TRPA1 agonist responders were IB4-positive but CGRP-negative. Among TRPA1-null DRGs, few small neurons (2–4%) responded to either TRPA1 agonist, indicating that both cinnamaldehyde and AITC specifically target TRPA1. Additionally, few large neurons (≥27 µm diameter) responded to AITC (6%) or cinnamaldehyde (4%), confirming that most large-diameter somata lack functional TRPA1. Comparison of mouse and rat DRGs showed that the majority of TRPA1-responsive neurons in both species were IB4-positive. Together, these data demonstrate that TRPA1 is functionally expressed

  11. Tiam1 Regulates the Wnt/Dvl/Rac1 Signaling Pathway and the Differentiation of Midbrain Dopaminergic Neurons

    Science.gov (United States)

    Čajánek, Lukáš; Ganji, Ranjani Sri; Henriques-Oliveira, Catarina; Theofilopoulos, Spyridon; Koník, Peter

    2013-01-01

    Understanding the mechanisms that drive the differentiation of dopaminergic (DA) neurons is crucial for successful development of novel therapies for Parkinson's disease, in which DA neurons progressively degenerate. However, the mechanisms underlying the differentiation-promoting effects of Wnt5a on DA precursors are poorly understood. Here, we present the molecular and functional characterization of a signaling pathway downstream of Wnt5a, the Wnt/Dvl/Rac1 pathway. First, we characterize the interaction between Rac1 and Dvl and identify the N-terminal part of Dvl3 as necessary for Rac1 binding. Next, we show that Tiam1, a Rac1 guanosine exchange factor (GEF), is expressed in the ventral midbrain, interacts with Dvl, facilitates Dvl-Rac1 interaction, and is required for Dvl- or Wnt5a-induced activation of Rac1. Moreover, we show that Wnt5a promotes whereas casein kinase 1 (CK1), a negative regulator of the Wnt/Dvl/Rac1 pathway, abolishes the interactions between Dvl and Tiam1. Finally, using ventral midbrain neurosphere cultures, we demonstrate that the generation of DA neurons in culture is impaired after Tiam1 knockdown, indicating that Tiam1 is required for midbrain DA differentiation. In summary, our data identify Tiam1 as a novel regulator of DA neuron development and as a Dvl-associated and Rac1-specific GEF acting in the Wnt/Dvl/Rac1 pathway. PMID:23109420

  12. [Morphological changes of neurons and neuroglial cells in the brain of senescence-accelerated prone 1 (SAMP1) mice].

    Science.gov (United States)

    Khudoerkov, R M; Sal'kov, V N; Sal'nikova, O V; Sobolev, V B

    2014-01-01

    Computerized morphometry was used to examine the sizes of neuronal bodies and the compactness of arrangement of neurons and neuroglial cells in layers III and V of the sensorimotor cortex in senescence-accelerated prone 1 (SAMP1) mice (an experimental group) and senescence-accelerated-resistant strain 1 (SAMR1) ones (a control group). In the SAMP1 mice as compared to the SAMR1 ones, the neuronal body sizes were significantly unchanged; the compactness of their arrangement decreased by 17 and 20% in layers III and V, respectively; that of neuroglial cells significantly increased by 14% in layer III only. In the SAMP1 mice versus the SAMR1 ones, the glial index rose by 36% in layer III and by 24% in layer V. During simulation of physiological aging, the sizes of neuronal bodies were shown to be virtually unchanged in the cerebral cortex; the compactness of their arrangement (cell counts) moderately reduced and that of neuroglial cells increased, which caused a rise in the glioneuronal index that was indicative of the enhanced supporting function of neuroglial cells during the physiological aging of brain structures.

  13. BIG1 is required for the survival of deep layer neurons, neuronal polarity, and the formation of axonal tracts between the thalamus and neocortex in developing brain.

    Directory of Open Access Journals (Sweden)

    Jia-Jie Teoh

    Full Text Available BIG1, an activator protein of the small GTPase, Arf, and encoded by the Arfgef1 gene, is one of candidate genes for epileptic encephalopathy. To know the involvement of BIG1 in epileptic encephalopathy, we analyzed BIG1-deficient mice and found that BIG1 regulates neurite outgrowth and brain development in vitro and in vivo. The loss of BIG1 decreased the size of the neocortex and hippocampus. In BIG1-deficient mice, the neuronal progenitor cells (NPCs and the interneurons were unaffected. However, Tbr1+ and Ctip2+ deep layer (DL neurons showed spatial-temporal dependent apoptosis. This apoptosis gradually progressed from the piriform cortex (PIR, peaked in the neocortex, and then progressed into the hippocampus from embryonic day 13.5 (E13.5 to E17.5. The upper layer (UL and DL order in the neocortex was maintained in BIG1-deficient mice, but the excitatory neurons tended to accumulate before their destination layers. Further pulse-chase migration assay showed that the migration defect was non-cell autonomous and secondary to the progression of apoptosis into the BIG1-deficient neocortex after E15.5. In BIG1-deficient mice, we observed an ectopic projection of corticothalamic axons from the primary somatosensory cortex (S1 into the dorsal lateral geniculate nucleus (dLGN. The thalamocortical axons were unable to cross the diencephalon-telencephalon boundary (DTB. In vitro, BIG1-deficient neurons showed a delay in neuronal polarization. BIG1-deficient neurons were also hypersensitive to low dose glutamate (5 μM, and died via apoptosis. This study showed the role of BIG1 in the survival of DL neurons in developing embryonic brain and in the generation of neuronal polarity.

  14. The transcription factor Nerfin-1 prevents reversion of neurons into neural stem cells.

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    Froldi, Francesca; Szuperak, Milan; Weng, Chen-Fang; Shi, Wei; Papenfuss, Anthony T; Cheng, Louise Y

    2015-01-15

    Cellular dedifferentiation is the regression of a cell from a specialized state to a more multipotent state and is implicated in cancer. However, the transcriptional network that prevents differentiated cells from reacquiring stem cell fate is so far unclear. Neuroblasts (NBs), the Drosophila neural stem cells, are a model for the regulation of stem cell self-renewal and differentiation. Here we show that the Drosophila zinc finger transcription factor Nervous fingers 1 (Nerfin-1) locks neurons into differentiation, preventing their reversion into NBs. Following Prospero-dependent neuronal specification in the ganglion mother cell (GMC), a Nerfin-1-specific transcriptional program maintains differentiation in the post-mitotic neurons. The loss of Nerfin-1 causes reversion to multipotency and results in tumors in several neural lineages. Both the onset and rate of neuronal dedifferentiation in nerfin-1 mutant lineages are dependent on Myc- and target of rapamycin (Tor)-mediated cellular growth. In addition, Nerfin-1 is required for NB differentiation at the end of neurogenesis. RNA sequencing (RNA-seq) and chromatin immunoprecipitation (ChIP) analysis show that Nerfin-1 administers its function by repression of self-renewing-specific and activation of differentiation-specific genes. Our findings support the model of bidirectional interconvertibility between neural stem cells and their post-mitotic progeny and highlight the importance of the Nerfin-1-regulated transcriptional program in neuronal maintenance. © 2015 Froldi et al.; Published by Cold Spring Harbor Laboratory Press.

  15. Synaptic and genomic responses to JNK and AP-1 signaling in Drosophila neurons

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    Bohmann Dirk

    2005-06-01

    Full Text Available Abstract Background The transcription factor AP-1 positively controls synaptic plasticity at the Drosophila neuromuscular junction. Although in motor neurons, JNK has been shown to activate AP-1, a positive regulator of growth and strength at the larval NMJ, the consequences of JNK activation are poorly studied. In addition, the downstream transcriptional targets of JNK and AP-1 signaling in the Drosophila nervous system have yet to be identified. Here, we further investigated the role of JNK signaling at this model synapse employing an activated form of JNK-kinase; and using Serial Analysis of Gene Expression and oligonucleotide microarrays, searched for candidate early targets of JNK or AP-1 dependent transcription in neurons. Results Temporally-controlled JNK induction in postembryonic motor neurons triggers synaptic growth at the NMJ indicating a role in developmental plasticity rather than synaptogenesis. An unexpected observation that JNK activation also causes a reduction in transmitter release is inconsistent with JNK functioning solely through AP-1 and suggests an additional, yet-unidentified pathway for JNK signaling in motor neurons. SAGE profiling of mRNA expression helps define the neural transcriptome in Drosophila. Though many putative AP-1 and JNK target genes arose from the genomic screens, few were confirmed in subsequent validation experiments. One potentially important neuronal AP-1 target discovered, CG6044, was previously implicated in olfactory associative memory. In addition, 5 mRNAs regulated by RU486, a steroid used to trigger conditional gene expression were identified. Conclusion This study demonstrates a novel role for JNK signaling at the larval neuromuscular junction and provides a quantitative profile of gene transcription in Drosophila neurons. While identifying potential JNK/AP-1 targets it reveals the limitations of genome-wide analyses using complex tissues like the whole brain.

  16. Ctip2-, Satb2-, Prox1-, and GAD65-Expressing Neurons in Rat Cultures: Preponderance of Single- and Double-Positive Cells, and Cell Type-Specific Expression of Neuron-Specific Gene Family Members, Nsg-1 (NEEP21) and Nsg-2 (P19).

    Science.gov (United States)

    Digilio, Laura; Yap, Chan Choo; Winckler, Bettina

    2015-01-01

    The brain consists of many distinct neuronal cell types, but which cell types are present in widely used primary cultures of embryonic rodent brain is often not known. We characterized how abundantly four cell type markers (Ctip2, Satb2, Prox1, GAD65) were represented in cultured rat neurons, how easily neurons expressing different markers can be transfected with commonly used plasmids, and whether neuronal-enriched endosomal proteins Nsg-1 (NEEP21) and Nsg-2 (P19) are ubiquitously expressed in all types of cultured neurons. We found that cultured neurons stably maintain cell type identities that are reflective of cell types in vivo. This includes neurons maintaining simultaneous expression of two transcription factors, such as Ctip2+/Satb2+ or Prox1+/Ctip2+ double-positive cells, which have also been described in vivo. Secondly, we established the superior efficiency of CAG promoters for both Lipofectamine-mediated transfection as well as for electroporation. Thirdly, we discovered that Nsg-1 and Nsg-2 were not expressed equally in all neurons: whereas high levels of both Nsg-1 and Nsg-2 were found in Satb2-, Ctip2-, and GAD65-positive neurons, Prox1-positive neurons in hippocampal cultures expressed low levels of both. Our findings thus highlight the importance of identifying neuronal cell types for doing cell biology in cultured neurons: Keeping track of neuronal cell type might uncover effects in assays that might otherwise be masked by the mixture of responsive and non-responsive neurons in the dish.

  17. Fractalkine/CX3CL1 protects striatal neurons from synergistic morphine and HIV-1 Tat-induced dendritic losses and death

    Directory of Open Access Journals (Sweden)

    Suzuki Masami

    2011-11-01

    Full Text Available Abstract Background Fractalkine/CX3CL1 and its cognate receptor CX3CR1 are abundantly expressed in the CNS. Fractalkine is an unusual C-X3-C motif chemokine that is important in neuron-microglial communication, a co-receptor for HIV infection, and can be neuroprotective. To assess the effects of fractalkine on opiate-HIV interactive neurotoxicity, wild-type murine striatal neurons were co-cultured with mixed glia from the striata of wild-type or Cx3cr1 knockout mice ± HIV-1 Tat and/or morphine. Time-lapse digital images were continuously recorded at 20 min intervals for up to 72 h using computer-aided microscopy to track the same cells repeatedly. Results Co-exposure to Tat and morphine caused synergistic increases in neuron death, dendritic pruning, and microglial motility as previously reported. Exogenous fractalkine prevented synergistic Tat and morphine-induced dendritic losses and neuron death even though the inflammatory mediator TNF-α remained significantly elevated. Antibody blockade of CX3CR1 mimicked the toxic effects of morphine plus Tat, but did not add to their toxicity; while fractalkine failed to protect wild-type neurons co-cultured with Cx3cr1-/--null glia against morphine and Tat toxicity. Exogenous fractalkine also normalized microglial motility, which is elevated by Tat and morphine co-exposure, presumably limiting microglial surveillance that may lead to toxic effects on neurons. Fractalkine immunofluorescence was expressed in neurons and to a lesser extent by other cell types, whereas CX3CR1 immunoreactivity or GFP fluorescence in cells cultured from the striatum of Cx3cr1-/- (Cx3cr1GFP/GFP mice were associated with microglia. Immunoblotting shows that fractalkine levels were unchanged following Tat and/or morphine exposure and there was no increase in released fractalkine as determined by ELISA. By contrast, CX3CR1 protein levels were markedly downregulated. Conclusions The results suggest that deficits in fractalkine

  18. The digital bee brain: integrating and managing neurons in a common 3D reference system

    Directory of Open Access Journals (Sweden)

    Jürgen Rybak

    2010-07-01

    Full Text Available The honeybee standard brain (HSB serves as an interactive tool for relating morphologies of bee brain neurons and provides a reference system for functional and bibliographical properties (http://www.neurobiologie.fu-berlin.de/beebrain/. The ultimate goal is to document not only the morphological network properties of neurons collected from separate brains, but also to establish a graphical user interface for a neuron-related data base. Here, we review the current methods and protocols used to incorporate neuronal reconstructions into the HSB. Our registration protocol consists of two separate steps applied to imaging data from two-channel confocal microscopy scans: (1 The reconstruction of the neuron, facilitated by an automatic extraction of the neuron’s skeleton based on threshold segmentation, and (2 the semi-automatic 3D segmentation of the neuropils and their registration with the HSB. The integration of neurons in the HSB is performed by applying the transformation computed in step (2 to the reconstructed neurons of step (1. The most critical issue of this protocol in terms of user interaction time – the segmentation process – is drastically improved by the use of a model-based segmentation process. Furthermore, the underlying statistical shape models (SSM allow the visualization and analysis of characteristic variations in large sets of bee brain data. The anatomy of neural networks composed of multiple neurons that are registered into the HSB are visualized by depicting the 3D reconstructions together with semantic information with the objective to integrate data from multiple sources (electrophysiology, imaging, immunocytochemistry, molecular biology. Ultimately, this will allow the user to specify cell types and retrieve their morphologies along with physiological characterizations.

  19. Delta-like 1 participates in the specification of ventral midbrain progenitor derived dopaminergic neurons

    DEFF Research Database (Denmark)

    Bauer, Matthias; Szulc, Jolanta; Meyer, Morten

    2008-01-01

    function of Dlk1 in VM neuron development, we investigated the effect of soluble Dlk1 protein as well as the intrinsic Dlk1 function in the course of VM progenitor expansion and dopaminergic (DA) neuron differentiation in vitro. Dlk1 treatment during expansion increased DA progenitor proliferation...

  20. miR-34b/c Regulates Wnt1 and Enhances Mesencephalic Dopaminergic Neuron Differentiation

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    Roberto De Gregorio

    2018-04-01

    Full Text Available Summary: The differentiation of dopaminergic neurons requires concerted action of morphogens and transcription factors acting in a precise and well-defined time window. Very little is known about the potential role of microRNA in these events. By performing a microRNA-mRNA paired microarray screening, we identified miR-34b/c among the most upregulated microRNAs during dopaminergic differentiation. Interestingly, miR-34b/c modulates Wnt1 expression, promotes cell cycle exit, and induces dopaminergic differentiation. When combined with transcription factors ASCL1 and NURR1, miR-34b/c doubled the yield of transdifferentiated fibroblasts into dopaminergic neurons. Induced dopaminergic (iDA cells synthesize dopamine and show spontaneous electrical activity, reversibly blocked by tetrodotoxin, consistent with the electrophysiological properties featured by brain dopaminergic neurons. Our findings point to a role for miR-34b/c in neuronal commitment and highlight the potential of exploiting its synergy with key transcription factors in enhancing in vitro generation of dopaminergic neurons. : In this article, Bellenchi and colleagues show that the microRNA miR-34b/c is expressed in FACS-purified Pitx3-GFP+ neurons and promotes dopaminergic differentiation by negative modulating Wnt1 and the downstream WNT signaling pathway. Induced dopaminergic cells, expressing miR-34b/c, synthesize dopamine and show the electrophysiological properties featured by brain dopaminergic neurons. Keywords: microRNA, dopamine, mESC, miR34b/c, epiSC, transdifferentiation, Wnt1, Wnt pathway, reprogramming

  1. PINK1 Primes Parkin-Mediated Ubiquitination of PARIS in Dopaminergic Neuronal Survival

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    Yunjong Lee

    2017-01-01

    Full Text Available Mutations in PTEN-induced putative kinase 1 (PINK1 and parkin cause autosomal-recessive Parkinson’s disease through a common pathway involving mitochondrial quality control. Parkin inactivation leads to accumulation of the parkin interacting substrate (PARIS, ZNF746 that plays an important role in dopamine cell loss through repression of proliferator-activated receptor gamma coactivator-1-alpha (PGC-1α promoter activity. Here, we show that PARIS links PINK1 and parkin in a common pathway that regulates dopaminergic neuron survival. PINK1 interacts with and phosphorylates serines 322 and 613 of PARIS to control its ubiquitination and clearance by parkin. PINK1 phosphorylation of PARIS alleviates PARIS toxicity, as well as repression of PGC-1α promoter activity. Conditional knockdown of PINK1 in adult mouse brains leads to a progressive loss of dopaminergic neurons in the substantia nigra that is dependent on PARIS. Altogether, these results uncover a function of PINK1 to direct parkin-PARIS-regulated PGC-1α expression and dopaminergic neuronal survival.

  2. Imaging of intracranial neuronal and mixed neuronal-glial tumours

    International Nuclear Information System (INIS)

    Cui Shimin; Qin Jinxi; Zhang Leili; Liu Meili; Jin Song; Yan Shixin; Liu Li; Dai Weiying; Li Tao; Gao Man

    2001-01-01

    Objective: To investigate the characteristic clinical, imaging , and pathologic findings of intracranial neuronal and mixed neuronal-glial tumours. Methods: The imaging findings of surgery and pathobiology proved intracranial neuronal and mixed neuronal-glial tumours in 14 cases (7 male and 7 female, ranging in age from 6-56 years; mean age 33.8 years) were retrospectively analyzed. Results: Eight gangliogliomas were located in the frontal lobe (4 cases), temporal lobe (1 case), front- temporal lobe (2 cases), and pons (1 case). They appeared as iso-or low density on CT, iso-or low signal intensity on T 1 WI, and high signal intensity on T 2 WI on MR imaging. Two central neurocytomas were located in the supratentorial ventricles. Four desmoplastic gangliogliomas were seen as cystic masses, appearing as low signal intensity on T 1 WI and high signal intensity on T 2 WI. Conclusion: Intracranial neuronal and mixed neuronal-glial tumours had imaging characteristics. Combined with clinical history, it was possible to make a tendency preoperative diagnosis using CT or MR

  3. PI3K/Akt1 signalling specifies foregut precursors by generating regionalized extra-cellular matrix

    DEFF Research Database (Denmark)

    Villegas, S Nahuel; Rothová, Michaela; Barrios-Llerena, Martin E

    2013-01-01

    -to-mesenchymal transition (EMT). Akt1 transduced this activity via modifications to the extracellular matrix (ECM) and appropriate ECM could itself induce anterior endodermal identity in the absence of PI3K signalling. PI3K/Akt1-modified ECM contained low levels of Fibronectin (Fn1) and we found that Fn1 dose was key...... to specifying anterior endodermal identity in vivo and in vitro. Thus, localized PI3K activity affects ECM composition and ECM in turn patterns the endoderm. DOI: http://dx.doi.org/10.7554/eLife.00806.001....

  4. Enhancement of synchronized activity between hippocampal CA1 neurons during initial storage of associative fear memory.

    Science.gov (United States)

    Liu, Yu-Zhang; Wang, Yao; Shen, Weida; Wang, Zhiru

    2017-08-01

    Learning and memory storage requires neuronal plasticity induced in the hippocampus and other related brain areas, and this process is thought to rely on synchronized activity in neural networks. We used paired whole-cell recording in vivo to examine the synchronized activity that was induced in hippocampal CA1 neurons by associative fear learning. We found that both membrane potential synchronization and spike synchronization of CA1 neurons could be transiently enhanced after task learning, as observed on day 1 but not day 5. On day 1 after learning, CA1 neurons showed a decrease in firing threshold and rise times of suprathreshold membrane potential changes as well as an increase in spontaneous firing rates, possibly contributing to the enhancement of spike synchronization. The transient enhancement of CA1 neuronal synchronization may play important roles in the induction of neuronal plasticity for initial storage and consolidation of associative memory. The hippocampus is critical for memory acquisition and consolidation. This function requires activity- and experience-induced neuronal plasticity. It is known that neuronal plasticity is largely dependent on synchronized activity. As has been well characterized, repetitive correlated activity of presynaptic and postsynaptic neurons can lead to long-term modifications at their synapses. Studies on network activity have also suggested that memory processing in the hippocampus may involve learning-induced changes of neuronal synchronization, as observed in vivo between hippocampal CA3 and CA1 networks as well as between the rhinal cortex and the hippocampus. However, further investigation of learning-induced synchronized activity in the hippocampus is needed for a full understanding of hippocampal memory processing. In this study, by performing paired whole-cell recording in vivo on CA1 pyramidal cells (PCs) in anaesthetized adult rats, we examined CA1 neuronal synchronization before and after associative fear

  5. Xbp1s in Pomc neurons connects ER stress with energy balance and glucose homeostasis.

    Science.gov (United States)

    Williams, Kevin W; Liu, Tiemin; Kong, Xingxing; Fukuda, Makoto; Deng, Yingfeng; Berglund, Eric D; Deng, Zhuo; Gao, Yong; Liu, Tianya; Sohn, Jong-Woo; Jia, Lin; Fujikawa, Teppei; Kohno, Daisuke; Scott, Michael M; Lee, Syann; Lee, Charlotte E; Sun, Kai; Chang, Yongsheng; Scherer, Philipp E; Elmquist, Joel K

    2014-09-02

    The molecular mechanisms underlying neuronal leptin and insulin resistance in obesity and diabetes remain unclear. Here we show that induction of the unfolded protein response transcription factor spliced X-box binding protein 1 (Xbp1s) in pro-opiomelanocortin (Pomc) neurons alone is sufficient to protect against diet-induced obesity as well as improve leptin and insulin sensitivity, even in the presence of strong activators of ER stress. We also demonstrate that constitutive expression of Xbp1s in Pomc neurons contributes to improved hepatic insulin sensitivity and suppression of endogenous glucose production. Notably, elevated Xbp1s levels in Pomc neurons also resulted in activation of the Xbp1s axis in the liver via a cell-nonautonomous mechanism. Together our results identify critical molecular mechanisms linking ER stress in arcuate Pomc neurons to acute leptin and insulin resistance as well as liver metabolism in diet-induced obesity and diabetes. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Mitochondrial Dynamics Mediated by Mitofusin 1 Is Required for POMC Neuron Glucose-Sensing and Insulin Release Control.

    Science.gov (United States)

    Ramírez, Sara; Gómez-Valadés, Alicia G; Schneeberger, Marc; Varela, Luis; Haddad-Tóvolli, Roberta; Altirriba, Jordi; Noguera, Eduard; Drougard, Anne; Flores-Martínez, Álvaro; Imbernón, Mónica; Chivite, Iñigo; Pozo, Macarena; Vidal-Itriago, Andrés; Garcia, Ainhoa; Cervantes, Sara; Gasa, Rosa; Nogueiras, Ruben; Gama-Pérez, Pau; Garcia-Roves, Pablo M; Cano, David A; Knauf, Claude; Servitja, Joan-Marc; Horvath, Tamas L; Gomis, Ramon; Zorzano, Antonio; Claret, Marc

    2017-06-06

    Proopiomelanocortin (POMC) neurons are critical sensors of nutrient availability implicated in energy balance and glucose metabolism control. However, the precise mechanisms underlying nutrient sensing in POMC neurons remain incompletely understood. We show that mitochondrial dynamics mediated by Mitofusin 1 (MFN1) in POMC neurons couple nutrient sensing with systemic glucose metabolism. Mice lacking MFN1 in POMC neurons exhibited defective mitochondrial architecture remodeling and attenuated hypothalamic gene expression programs during the fast-to-fed transition. This loss of mitochondrial flexibility in POMC neurons bidirectionally altered glucose sensing, causing abnormal glucose homeostasis due to defective insulin secretion by pancreatic β cells. Fed mice lacking MFN1 in POMC neurons displayed enhanced hypothalamic mitochondrial oxygen flux and reactive oxygen species generation. Central delivery of antioxidants was able to normalize the phenotype. Collectively, our data posit MFN1-mediated mitochondrial dynamics in POMC neurons as an intrinsic nutrient-sensing mechanism and unveil an unrecognized link between this subset of neurons and insulin release. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Hoxb1 controls anteroposterior identity of vestibular projection neurons.

    Science.gov (United States)

    Chen, Yiju; Takano-Maruyama, Masumi; Fritzsch, Bernd; Gaufo, Gary O

    2012-01-01

    The vestibular nuclear complex (VNC) consists of a collection of sensory relay nuclei that integrates and relays information essential for coordination of eye movements, balance, and posture. Spanning the majority of the hindbrain alar plate, the rhombomere (r) origin and projection pattern of the VNC have been characterized in descriptive works using neuroanatomical tracing. However, neither the molecular identity nor developmental regulation of individual nucleus of the VNC has been determined. To begin to address this issue, we found that Hoxb1 is required for the anterior-posterior (AP) identity of precursors that contribute to the lateral vestibular nucleus (LVN). Using a gene-targeted Hoxb1-GFP reporter in the mouse, we show that the LVN precursors originate exclusively from r4 and project to the spinal cord in the stereotypic pattern of the lateral vestibulospinal tract that provides input into spinal motoneurons driving extensor muscles of the limb. The r4-derived LVN precursors express the transcription factors Phox2a and Lbx1, and the glutamatergic marker Vglut2, which together defines them as dB2 neurons. Loss of Hoxb1 function does not alter the glutamatergic phenotype of dB2 neurons, but alters their stereotyped spinal cord projection. Moreover, at the expense of Phox2a, the glutamatergic determinants Lmx1b and Tlx3 were ectopically expressed by dB2 neurons. Our study suggests that the Hox genes determine the AP identity and diversity of vestibular precursors, including their output target, by coordinating the expression of neurotransmitter determinant and target selection properties along the AP axis.

  8. Neuregulin-1 is neuroprotective in a rat model of organophosphate-induced delayed neuronal injury

    International Nuclear Information System (INIS)

    Li, Yonggang; Lein, Pamela J.; Liu, Cuimei; Bruun, Donald A.; Giulivi, Cecilia; Ford, Gregory D.; Tewolde, Teclemichael; Ross-Inta, Catherine; Ford, Byron D.

    2012-01-01

    Current medical countermeasures against organophosphate (OP) nerve agents are effective in reducing mortality, but do not sufficiently protect the CNS from delayed brain damage and persistent neurological symptoms. In this study, we examined the efficacy of neuregulin-1 (NRG-1) in protecting against delayed neuronal cell death following acute intoxication with the OP diisopropylflurophosphate (DFP). Adult male Sprague–Dawley rats were pretreated with pyridostigmine (0.1 mg/kg BW, i.m.) and atropine methylnitrate (20 mg/kg BW, i.m.) prior to DFP (9 mg/kg BW, i.p.) intoxication to increase survival and reduce peripheral signs of cholinergic toxicity but not prevent DFP-induced seizures or delayed neuronal injury. Pretreatment with NRG-1 did not protect against seizures in rats exposed to DFP. However, neuronal injury was significantly reduced in most brain regions by pretreatment with NRG-1 isoforms NRG-EGF (3.2 μg/kg BW, i.a) or NRG-GGF2 (48 μg/kg BW, i.a.) as determined by FluroJade-B labeling in multiple brain regions at 24 h post-DFP injection. NRG-1 also blocked apoptosis and oxidative stress-mediated protein damage in the brains of DFP-intoxicated rats. Administration of NRG-1 at 1 h after DFP injection similarly provided significant neuroprotection against delayed neuronal injury. These findings identify NRG-1 as a promising adjuvant therapy to current medical countermeasures for enhancing neuroprotection against acute OP intoxication. -- Highlights: ► NRG-1 blocked DFP induced neuronal injury. ► NRG-1 did not protect against seizures in rats exposed to DFP. ► NRG-1 blocked apoptosis and oxidative stress in the brains of DFP-intoxicated rats. ► Administration of NRG-1 at 1 h after DFP injection prevented delayed neuronal injury.

  9. Forgetting in C. elegans Is Accelerated by Neuronal Communication via the TIR-1/JNK-1 Pathway

    Directory of Open Access Journals (Sweden)

    Akitoshi Inoue

    2013-03-01

    Full Text Available The control of memory retention is important for proper responses to constantly changing environments, but the regulatory mechanisms underlying forgetting have not been fully elucidated. Our genetic analyses in C. elegans revealed that mutants of the TIR-1/JNK-1 pathway exhibited prolonged retention of olfactory adaptation and salt chemotaxis learning. In olfactory adaptation, conditioning induces attenuation of odor-evoked Ca2+ responses in olfactory neurons, and this attenuation is prolonged in the TIR-1/JNK-1-pathway mutant animals. We also found that a pair of neurons in which the pathway functions is required for the acceleration of forgetting, but not for sensation or adaptation, in wild-type animals. In addition, the neurosecretion from these cells is important for the acceleration of forgetting. Therefore, we propose that these neurons accelerate forgetting through the TIR-1/JNK-1 pathway by sending signals that directly or indirectly stimulate forgetting.

  10. Neuron-specific antioxidant OXR1 extends survival of a mouse model of amyotrophic lateral sclerosis.

    Science.gov (United States)

    Liu, Kevin X; Edwards, Benjamin; Lee, Sheena; Finelli, Mattéa J; Davies, Ben; Davies, Kay E; Oliver, Peter L

    2015-05-01

    Amyotrophic lateral sclerosis is a devastating neurodegenerative disorder characterized by the progressive loss of spinal motor neurons. While the aetiological mechanisms underlying the disease remain poorly understood, oxidative stress is a central component of amyotrophic lateral sclerosis and contributes to motor neuron injury. Recently, oxidation resistance 1 (OXR1) has emerged as a critical regulator of neuronal survival in response to oxidative stress, and is upregulated in the spinal cord of patients with amyotrophic lateral sclerosis. Here, we tested the hypothesis that OXR1 is a key neuroprotective factor during amyotrophic lateral sclerosis pathogenesis by crossing a new transgenic mouse line that overexpresses OXR1 in neurons with the SOD1(G93A) mouse model of amyotrophic lateral sclerosis. Interestingly, we report that overexpression of OXR1 significantly extends survival, improves motor deficits, and delays pathology in the spinal cord and in muscles of SOD1(G93A) mice. Furthermore, we find that overexpression of OXR1 in neurons significantly delays non-cell-autonomous neuroinflammatory response, classic complement system activation, and STAT3 activation through transcriptomic analysis of spinal cords of SOD1(G93A) mice. Taken together, these data identify OXR1 as the first neuron-specific antioxidant modulator of pathogenesis and disease progression in SOD1-mediated amyotrophic lateral sclerosis, and suggest that OXR1 may serve as a novel target for future therapeutic strategies. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain.

  11. Trafficking of cholesterol from cell bodies to distal axons in Niemann Pick C1-deficient neurons.

    Science.gov (United States)

    Karten, Barbara; Vance, Dennis E; Campenot, Robert B; Vance, Jean E

    2003-02-07

    Niemann Pick type C (NPC) disease is a progressive neurodegenerative disorder. In cells lacking functional NPC1 protein, endocytosed cholesterol accumulates in late endosomes/lysosomes. We utilized primary neuronal cultures in which cell bodies and distal axons reside in separate compartments to investigate the requirement of NPC1 protein for transport of cholesterol from cell bodies to distal axons. We have recently observed that in NPC1-deficient neurons compared with wild-type neurons, cholesterol accumulates in cell bodies but is reduced in distal axons (Karten, B., Vance, D. E., Campenot, R. B., and Vance, J. E. (2002) J. Neurochem. 83, 1154-1163). We now show that NPC1 protein is expressed in both cell bodies and distal axons. In NPC1-deficient neurons, cholesterol delivered to cell bodies from low density lipoproteins (LDLs), high density lipoproteins, or cyclodextrin complexes was transported into axons in normal amounts, whereas transport of endogenously synthesized cholesterol was impaired. Inhibition of cholesterol synthesis with pravastatin in wild-type and NPC1-deficient neurons reduced axonal growth. However, LDLs restored a normal rate of growth to wild-type but not NPC1-deficient neurons treated with pravastatin. Thus, although LDL cholesterol is transported into axons of NPC1-deficient neurons, this source of cholesterol does not sustain normal axonal growth. Over the lifespan of NPC1-deficient neurons, these defects in cholesterol transport might be responsible for the observed altered distribution of cholesterol between cell bodies and axons and, consequently, might contribute to the neurological dysfunction in NPC disease.

  12. Midbrain Gene Screening Identifies a New Mesoaccumbal Glutamatergic Pathway and a Marker for Dopamine Cells Neuroprotected in Parkinson's Disease.

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    Viereckel, Thomas; Dumas, Sylvie; Smith-Anttila, Casey J A; Vlcek, Bianca; Bimpisidis, Zisis; Lagerström, Malin C; Konradsson-Geuken, Åsa; Wallén-Mackenzie, Åsa

    2016-10-20

    The ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) of the midbrain are associated with Parkinson's disease (PD), schizophrenia, mood disorders and addiction. Based on the recently unraveled heterogeneity within the VTA and SNc, where glutamate, GABA and co-releasing neurons have been found to co-exist with the classical dopamine neurons, there is a compelling need for identification of gene expression patterns that represent this heterogeneity and that are of value for development of human therapies. Here, several unique gene expression patterns were identified in the mouse midbrain of which NeuroD6 and Grp were expressed within different dopaminergic subpopulations of the VTA, and TrpV1 within a small heterogeneous population. Optogenetics-coupled in vivo amperometry revealed a previously unknown glutamatergic mesoaccumbal pathway characterized by TrpV1-Cre-expression. Human GRP was strongly detected in non-melanized dopaminergic neurons within the SNc of both control and PD brains, suggesting GRP as a marker for neuroprotected neurons in PD. This study thus unravels markers for distinct subpopulations of neurons within the mouse and human midbrain, defines unique anatomical subregions within the VTA and exposes an entirely new glutamatergic pathway. Finally, both TRPV1 and GRP are implied in midbrain physiology of importance to neurological and neuropsychiatric disorders.

  13. Midbrain Gene Screening Identifies a New Mesoaccumbal Glutamatergic Pathway and a Marker for Dopamine Cells Neuroprotected in Parkinson’s Disease

    Science.gov (United States)

    Viereckel, Thomas; Dumas, Sylvie; Smith-Anttila, Casey J. A.; Vlcek, Bianca; Bimpisidis, Zisis; Lagerström, Malin C.; Konradsson-Geuken, Åsa; Wallén-Mackenzie, Åsa

    2016-01-01

    The ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) of the midbrain are associated with Parkinson’s disease (PD), schizophrenia, mood disorders and addiction. Based on the recently unraveled heterogeneity within the VTA and SNc, where glutamate, GABA and co-releasing neurons have been found to co-exist with the classical dopamine neurons, there is a compelling need for identification of gene expression patterns that represent this heterogeneity and that are of value for development of human therapies. Here, several unique gene expression patterns were identified in the mouse midbrain of which NeuroD6 and Grp were expressed within different dopaminergic subpopulations of the VTA, and TrpV1 within a small heterogeneous population. Optogenetics-coupled in vivo amperometry revealed a previously unknown glutamatergic mesoaccumbal pathway characterized by TrpV1-Cre-expression. Human GRP was strongly detected in non-melanized dopaminergic neurons within the SNc of both control and PD brains, suggesting GRP as a marker for neuroprotected neurons in PD. This study thus unravels markers for distinct subpopulations of neurons within the mouse and human midbrain, defines unique anatomical subregions within the VTA and exposes an entirely new glutamatergic pathway. Finally, both TRPV1 and GRP are implied in midbrain physiology of importance to neurological and neuropsychiatric disorders. PMID:27762319

  14. IGF-1: elixir for motor neuron diseases.

    Science.gov (United States)

    Papanikolaou, Theodora; Ellerby, Lisa M

    2009-08-13

    Modulation of testosterone levels is a therapeutic approach for spinal and bulbar muscular atrophy (SBMA), a polyglutamine disorder that affects the motor neurons. The article by Palazzolo et al. in this issue of Neuron provides compelling evidence that the expression of insulin growth hormone is a potential therapeutic for SBMA.

  15. [Empathy and mirror neurons. A view on contemporary neuropsychological empathy research].

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    Häusser, Leonard F

    2012-01-01

    Neurons firing both to specific actions performed by self and matching actions performed by others are classified as mirror neurons. Since its discovery in 1991, this phenomenon has been surveyed in the field of motor and sensorimotor function and incipiently in the field of language and emotions. The research group of Giacomo Rizzolatti assumes that mirror neurons form the biological basis of compassion and thereby of affective empathic experience. The research regarding mirror neurons is yet in early stages and further research is required to specify mirror neuron systems. In view of empathy it is the insula which is of central importance for the recognition of disgust. The discovery of mirror neurons allows a comprehension of empathy as an immediate and compassionate partaking of a response, enabling an understanding of the other persons feeling. At the same time, the resonating affect remains allocated to the other person, distinguishing this comprehensive process from a mere emotional contagion. At present, the phenomenon of mirror neurons is gaining clinical relevance in the field of autism spectrum disorders and apoplexia. One's own ability for empathy as well as promoting empathetic abilities of others is of central importance for the clinical praxis, in particular concerning the treatment of children and adolescents.

  16. Differential induction of Toll-like receptors & type 1 interferons by Sabin attenuated & wild type 1 polioviruses in human neuronal cells.

    Science.gov (United States)

    Mohanty, Madhu C; Deshpande, Jagadish M

    2013-01-01

    Polioviruses are the causative agent of paralytic poliomyelitis. Attenuated polioviruses (Sabin oral poliovirus vaccine strains) do not replicate efficiently in neurons as compared to the wild type polioviruses and therefore do not cause disease. This study was aimed to investigate the differential host immune response to wild type 1 poliovirus (wild PV) and Sabin attenuated type 1 poliovirus (Sabin PV) in cultured human neuronal cells. By using flow cytometry and real time PCR methods we examined host innate immune responses and compared the role of toll like receptors (TLRs) and cytoplasmic RNA helicases in cultured human neuronal cells (SK-N-SH) infected with Sabin PV and wild PV. Human neuronal cells expressed very low levels of TLRs constitutively. Sabin PV infection induced significantly higher expression of TLR3, TLR7 and melanoma differentiation-associated protein-5 (MDA-5) m-RNA in neuronal cells at the beginning of infection (up to 4 h) as compared to wild PV. Further, Sabin PV also induced the expression of interferon α/β at early time point of infection. The induced expression of IFN α/β gene by Sabin PV in neuronal cells could be suppressed by inhibiting TLR7. Neuronal cell innate immune response to Sabin and wild polioviruses differ significantly for TLR3, TLR7, MDA5 and type 1 interferons. Effects of TLR7 activation and interferon production and Sabin virus replication in neuronal cells need to be actively investigated in future studies.

  17. Neuronal Rho GTPase Rac1 elimination confers neuroprotection in a mouse model of permanent ischemic stroke.

    Science.gov (United States)

    Karabiyik, Cansu; Fernandes, Rui; Figueiredo, Francisco Rosário; Socodato, Renato; Brakebusch, Cord; Lambertsen, Kate Lykke; Relvas, João Bettencourt; Santos, Sofia Duque

    2017-09-28

    The Rho GTPase Rac1 is a multifunctional protein involved in distinct pathways ranging from development to pathology. The aim of the present study was to unravel the contribution of neuronal Rac1 in regulating the response to brain injury induced by permanent focal cerebral ischemia (pMCAO). Our results show that pMCAO significantly increased total Rac1 levels in wild type mice, mainly through rising nuclear Rac1, while a reduction in Rac1 activation was observed. Such changes preceded cell death induced by excitotoxic stress. Pharmacological inhibition of Rac1 in primary neuronal cortical cells prevented the increase in oxidative stress induced after overactivation of glutamate receptors. However, this was not sufficient to prevent the associated neuronal cell death. In contrast, RNAi-mediated knock down of Rac1 in primary cortical neurons prevented cell death elicited by glutamate excitotoxicity and decreased the activity of NADPH oxidase. To test whether in vivo down regulation of neuronal Rac1 was neuroprotective after pMCAO, we used tamoxifen-inducible neuron-specific conditional Rac1-knockout mice. We observed a significant 50% decrease in brain infarct volume of knockout mice and a concomitant increase in HIF-1α expression compared to littermate control mice, demonstrating that ablation of Rac1 in neurons is neuroprotective. Transmission electron microscopy performed in the ischemic brain showed that lysosomes in the infarct of Rac1- knockout mice were preserved at similar levels to those of non-infarcted tissue, while littermate mice displayed a decrease in the number of lysosomes, further corroborating the notion that Rac1 ablation in neurons is neuroprotective. Our results demonstrate that Rac1 plays important roles in the ischemic pathological cascade and that modulation of its levels is of therapeutic interest. © 2017 International Society of Neuropathology.

  18. NMDA receptor dependent PGC-1alpha up-regulation protects the cortical neuron against oxygen-glucose deprivation/reperfusion injury.

    Science.gov (United States)

    Luo, Yun; Zhu, Wenjing; Jia, Jia; Zhang, Chenyu; Xu, Yun

    2009-09-01

    The peroxisome proliferator activated receptor coactivator 1 alpha (PGC-1alpha) is a nuclear transcriptional coactivator that is widely expressed in the brain areas. Over-expression of PGC-1alpha can protect neuronal cells from oxidant-induced injury. The purpose of the current study is to investigate the role of PGC-1alpha in the oxygen (anoxia) deprivation (OGD) neurons. The PGC-1alpha mRNA and protein level between control and OGD neurons were examined by real-time PCR and Western blot. More PGC-1alpha expression was found in the OGD neurons compared with the normal group. Over-expression of PGC-1alpha suppressed cell apoptosis while inhibition of the PGC-1alpha expression induced cell apoptosis in OGD neurons. Furthermore, increase of PGC-1alpha resulted in activation of N-methyl-D-aspartate (NMDA) receptor, p38, and ERK mitogen-activated protein kinase (MAPK) pathway. The blocking of the NMDA receptor by its antagonists MK-801 reduced PGC-1alpha mRNA expression in OGD neurons, while NMDA itself can directly induce the expression of PGC-1alpha in neuronal cells. At the same time, PD98059 (ERK MAPK inhibitor) and SB203580 (P38 MAPK inhibitor) also prevented the up-regulation of PGC-1alpha in OGD neurons and MK801 can inhibit the expression of P38 and ERK MAPK. These data suggested that the expression of PGC-1alpha was up-regulated in OGD mice cortical neurons, which protected the neurons against OGD injury. Moreover, this effect was correlated to the NMDA receptor and the ERK and P38 MAPK pathway. The protective effect of PGC-1alpha on OGD cortical neurons may be useful for stroke therapy.

  19. Assimilation of Biophysical Neuronal Dynamics in Neuromorphic VLSI.

    Science.gov (United States)

    Wang, Jun; Breen, Daniel; Akinin, Abraham; Broccard, Frederic; Abarbanel, Henry D I; Cauwenberghs, Gert

    2017-12-01

    Representing the biophysics of neuronal dynamics and behavior offers a principled analysis-by-synthesis approach toward understanding mechanisms of nervous system functions. We report on a set of procedures assimilating and emulating neurobiological data on a neuromorphic very large scale integrated (VLSI) circuit. The analog VLSI chip, NeuroDyn, features 384 digitally programmable parameters specifying for 4 generalized Hodgkin-Huxley neurons coupled through 12 conductance-based chemical synapses. The parameters also describe reversal potentials, maximal conductances, and spline regressed kinetic functions for ion channel gating variables. In one set of experiments, we assimilated membrane potential recorded from one of the neurons on the chip to the model structure upon which NeuroDyn was designed using the known current input sequence. We arrived at the programmed parameters except for model errors due to analog imperfections in the chip fabrication. In a related set of experiments, we replicated songbird individual neuron dynamics on NeuroDyn by estimating and configuring parameters extracted using data assimilation from intracellular neural recordings. Faithful emulation of detailed biophysical neural dynamics will enable the use of NeuroDyn as a tool to probe electrical and molecular properties of functional neural circuits. Neuroscience applications include studying the relationship between molecular properties of neurons and the emergence of different spike patterns or different brain behaviors. Clinical applications include studying and predicting effects of neuromodulators or neurodegenerative diseases on ion channel kinetics.

  20. Reduced sensory synaptic excitation impairs motor neuron function via Kv2.1 in spinal muscular atrophy.

    Science.gov (United States)

    Fletcher, Emily V; Simon, Christian M; Pagiazitis, John G; Chalif, Joshua I; Vukojicic, Aleksandra; Drobac, Estelle; Wang, Xiaojian; Mentis, George Z

    2017-07-01

    Behavioral deficits in neurodegenerative diseases are often attributed to the selective dysfunction of vulnerable neurons via cell-autonomous mechanisms. Although vulnerable neurons are embedded in neuronal circuits, the contributions of their synaptic partners to disease process are largely unknown. Here we show that, in a mouse model of spinal muscular atrophy (SMA), a reduction in proprioceptive synaptic drive leads to motor neuron dysfunction and motor behavior impairments. In SMA mice or after the blockade of proprioceptive synaptic transmission, we observed a decrease in the motor neuron firing that could be explained by the reduction in the expression of the potassium channel Kv2.1 at the surface of motor neurons. Chronically increasing neuronal activity pharmacologically in vivo led to a normalization of Kv2.1 expression and an improvement in motor function. Our results demonstrate a key role of excitatory synaptic drive in shaping the function of motor neurons during development and the contribution of its disruption to a neurodegenerative disease.

  1. [ERK activation effects on GABA secretion inhibition induced by SDF-1 in hippocampal neurons of rats].

    Science.gov (United States)

    Zhang, Zi-juan; Guo, Mei-xia; Xing, Ying

    2015-09-01

    To investigate the effect of extracellular regulating kinase (ERK) signaling pathway on the secretion of gamma-aminobutyric acid (GABA) in cultured rat hippocampal neurons induced by stromal cell derived factor-1 (SDF-1). The hippocampal neurons of newborn SD rats were cultured and identified in vitro; the phosphorylation level of ERK1/2 was examined by Western blot; ELISA was used to detect the effect of PD98059, a ERK1/2 specific blocker on GABA secretion of cultured hippocampal neurons and Western blot were adopted to measure the protein expression levels of glutamate decarboxylase (GAD65/67) and gamma aminobutyric acid transporter (GAT); after blocking ERK1/2 signaling pathway with PD98059; RT-PCR was used to detect the mRNA expression levels of GAT-1 and GAD65 after treated with PD98059. The levels of ERKl/2 phosphorylation were increased significantly by SDF1 acting on hippocampal neurons, and CX-CR4 receptor blocker AMD3100, could inhibit SDF-1 induced ERK1/2 activation; SDF-1 could inhibit the secretion of GABA in cultured hippocampal neurons, and ERK1/2 specific inhibitor PD98059, could partly reverse the inhibition of GABA secretion by SDF-1. The effects of SDF-1 on cultured hippocampal neurons was to decrease the mRNA genesis of glutamic acid decarboxylase GAD65 and GABA transporter GAT-1, besides, ERK inhibitor PD98059 could effectively flip the effect of SDF-1. The results of Western blot showed that SDF-1 could inhibit the protein expression of GAT-1 and GAD65/67 in hippocampal neurons and the inhibition of GAT-1 and GAD65/67 protein expression could be partially restored by ERK1/2 blocker. SDF-1 acts on the CXCR4 of hippocampal neurons in vitro, and inhibits the expression of GAD by activating the ERK1/2 signaling pathway, and this may represent one possible pathway of GABA secretion inhibition.

  2. Neuroprotective effects of ginsenoside Rg1 against oxygen-glucose deprivation in cultured hippocampal neurons.

    Science.gov (United States)

    He, Qing; Sun, Jianguo; Wang, Qin; Wang, Wei; He, Bin

    2014-03-01

    Ginsenoside Rg1 (Rg1) is believed to be one of the main active principles in ginseng, a traditional Chinese medicine extensively used to enhance stamina and deal with fatigue as well as physical stress. It has been reported that Rg1 performs multiple biological activities, including neuroprotective activity. In this study, we investigated the efficacy of ginsenoside Rg1 on ischemia-reperfusion injury in cultured hippocampal cells and also probed its possible mechanisms. To establish a model of oxygen-glucose deprivation (OGD) and reperfusion, cultured hippocampal neurons were exposed to OGD for 2.5 hours, followed by a 24-hour reoxygenation. Cultured hippocampal neurons were randomly divided into control group, model group (vehicle), and ginsenoside Rg1 treatment groups (5μM, 20μM, 60μM). At 24 hours post-OGD, the intracellular free calcium concentration was detected using Furo-3/AM-loaded hippocampal neurons deprived of oxygen and glucose. Neuronal nitric oxide synthase (nNOS) activity was measured by chemical colorimetry. Cell apoptosis was evaluated by Hoechst staining, and the neuron viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Excitotoxic neuronal injury of OGD was demonstrated by the increase of intracellular free calcium concentrations and elevated nNOS activity in the model group compared with the control group. The intracellular free calcium concentrations and the nNOS activity in the groups receiving intermediate and high dose of ginsenoside Rg1 were significantly lower than those of the control group (p cell viability loss (p cell apoptosis induced by OGD. Ginsenoside Rg1 has neuroprotective effect on ischemia-reperfusion injury in cultured hippocampal cells mediated by blocking calcium over-influx into neuronal cells and decreasing the nNOS activity after OGD exposure. We infer that ginsenoside Rg1 may serve as a potential therapeutic agent for cerebral ischemia injury. Copyright © 2014

  3. Ebi/AP-1 suppresses pro-apoptotic genes expression and permits long-term survival of Drosophila sensory neurons.

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    Young-Mi Lim

    Full Text Available Sensory organs are constantly exposed to physical and chemical stresses that collectively threaten the survival of sensory neurons. Failure to protect stressed neurons leads to age-related loss of neurons and sensory dysfunction in organs in which the supply of new sensory neurons is limited, such as the human auditory system. Transducin β-like protein 1 (TBL1 is a candidate gene for ocular albinism with late-onset sensorineural deafness, a form of X-linked age-related hearing loss. TBL1 encodes an evolutionarily conserved F-box-like and WD40 repeats-containing subunit of the nuclear receptor co-repressor/silencing mediator for retinoid and thyroid hormone receptor and other transcriptional co-repressor complexes. Here we report that a Drosophila homologue of TBL1, Ebi, is required for maintenance of photoreceptor neurons. Loss of ebi function caused late-onset neuronal apoptosis in the retina and increased sensitivity to oxidative stress. Ebi formed a complex with activator protein 1 (AP-1 and was required for repression of Drosophila pro-apoptotic and anti-apoptotic genes expression. These results suggest that Ebi/AP-1 suppresses basal transcription levels of apoptotic genes and thereby protects sensory neurons from degeneration.

  4. Hoxb1 controls anteroposterior identity of vestibular projection neurons.

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    Yiju Chen

    Full Text Available The vestibular nuclear complex (VNC consists of a collection of sensory relay nuclei that integrates and relays information essential for coordination of eye movements, balance, and posture. Spanning the majority of the hindbrain alar plate, the rhombomere (r origin and projection pattern of the VNC have been characterized in descriptive works using neuroanatomical tracing. However, neither the molecular identity nor developmental regulation of individual nucleus of the VNC has been determined. To begin to address this issue, we found that Hoxb1 is required for the anterior-posterior (AP identity of precursors that contribute to the lateral vestibular nucleus (LVN. Using a gene-targeted Hoxb1-GFP reporter in the mouse, we show that the LVN precursors originate exclusively from r4 and project to the spinal cord in the stereotypic pattern of the lateral vestibulospinal tract that provides input into spinal motoneurons driving extensor muscles of the limb. The r4-derived LVN precursors express the transcription factors Phox2a and Lbx1, and the glutamatergic marker Vglut2, which together defines them as dB2 neurons. Loss of Hoxb1 function does not alter the glutamatergic phenotype of dB2 neurons, but alters their stereotyped spinal cord projection. Moreover, at the expense of Phox2a, the glutamatergic determinants Lmx1b and Tlx3 were ectopically expressed by dB2 neurons. Our study suggests that the Hox genes determine the AP identity and diversity of vestibular precursors, including their output target, by coordinating the expression of neurotransmitter determinant and target selection properties along the AP axis.

  5. Opposing effects of sirtuins on neuronal survival: SIRT1-mediated neuroprotection is independent of its deacetylase activity.

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    Jason A Pfister

    Full Text Available BACKGROUND: Growing evidence suggests that sirtuins, a family of seven distinct NAD-dependent enzymes, are involved in the regulation of neuronal survival. Indeed, SIRT1 has been reported to protect against neuronal death, while SIRT2 promotes neurodegeneration. The effect of SIRTs 3-7 on the regulation of neuronal survival, if any, has yet to be reported. METHODOLOGY AND PRINCIPAL FINDINGS: We examined the effect of expressing each of the seven SIRT proteins in healthy cerebellar granule neurons (CGNs or in neurons induced to die by low potassium (LK treatment. We report that SIRT1 protects neurons from LK-induced apoptosis, while SIRT2, SIRT3 and SIRT6 induce apoptosis in otherwise healthy neurons. SIRT5 is generally localized to both the nucleus and cytoplasm of CGNs and exerts a protective effect. In a subset of neurons, however, SIRT5 localizes to the mitochondria and in this case it promotes neuronal death. Interestingly, the protective effect of SIRT1 in neurons is not reduced by treatments with nicotinamide or sirtinol, two pharmacological inhibitors of SIRT1. Neuroprotection was also observed with two separate mutant forms of SIRT1, H363Y and H355A, both of which lack deacetylase activity. Furthermore, LK-induced neuronal death was not prevented by resveratrol, a pharmacological activator of SIRT1, at concentrations at which it activates SIRT1. We extended our analysis to HT-22 neuroblastoma cells which can be induced to die by homocysteic acid treatment. While the effects of most of the SIRT proteins were similar to that observed in CGNs, SIRT6 was modestly protective against homocysteic acid toxicity in HT-22 cells. SIRT5 was generally localized in the mitochondria of HT-22 cells and was apoptotic. CONCLUSIONS/SIGNIFICANCE: Overall, our study makes three contributions - (a it represents the first analysis of SIRT3-7 in the regulation of neuronal survival, (b it shows that neuroprotection by SIRT1 can be mediated by a novel, non

  6. Astrocytic αVβ3 integrin inhibits neurite outgrowth and promotes retraction of neuronal processes by clustering Thy-1.

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    Rodrigo Herrera-Molina

    Full Text Available Thy-1 is a membrane glycoprotein suggested to stabilize or inhibit growth of neuronal processes. However, its precise function has remained obscure, because its endogenous ligand is unknown. We previously showed that Thy-1 binds directly to α(Vβ(3 integrin in trans eliciting responses in astrocytes. Nonetheless, whether α(Vβ(3 integrin might also serve as a Thy-1-ligand triggering a neuronal response has not been explored. Thus, utilizing primary neurons and a neuron-derived cell line CAD, Thy-1-mediated effects of α(Vβ(3 integrin on growth and retraction of neuronal processes were tested. In astrocyte-neuron co-cultures, endogenous α(Vβ(3 integrin restricted neurite outgrowth. Likewise, α(Vβ(3-Fc was sufficient to suppress neurite extension in Thy-1(+, but not in Thy-1(- CAD cells. In differentiating primary neurons exposed to α(Vβ(3-Fc, fewer and shorter dendrites were detected. This effect was abolished by cleavage of Thy-1 from the neuronal surface using phosphoinositide-specific phospholipase C (PI-PLC. Moreover, α(Vβ(3-Fc also induced retraction of already extended Thy-1(+-axon-like neurites in differentiated CAD cells as well as of axonal terminals in differentiated primary neurons. Axonal retraction occurred when redistribution and clustering of Thy-1 molecules in the plasma membrane was induced by α(Vβ(3 integrin. Binding of α(Vβ(3-Fc was detected in Thy-1 clusters during axon retraction of primary neurons. Moreover, α(Vβ(3-Fc-induced Thy-1 clustering correlated in time and space with redistribution and inactivation of Src kinase. Thus, our data indicates that α(Vβ(3 integrin is a ligand for Thy-1 that upon binding not only restricts the growth of neurites, but also induces retraction of already existing processes by inducing Thy-1 clustering. We propose that these events participate in bi-directional astrocyte-neuron communication relevant to axonal repair after neuronal damage.

  7. AKAP localizes in a specific subset of TRPV1 and CaV1.2 positive nociceptive rat DRG neurons

    Science.gov (United States)

    Brandao, Katherine E.; Dell’Acqua, Mark L.; Levinson, Simon R.

    2016-01-01

    Modulation of phosphorylation states of ion channels is a critical step in the development of hyperalgesia during inflammation. Modulatory enhancement of channel activity may increase neuronal excitability and affect downstream targets such as gene transcription. The specificity required for such regulation of ion channels quickly occurs via targeting of protein kinases and phosphatases by the scaffolding A-kinase anchoring protein 79/150 (AKAP79/150). AKAP79/150 has been implicated in inflammatory pain by targeting PKA and PKC to the TRPV1 channel in peripheral sensory neurons, thus lowering threshold for activation by multiple inflammatory reagents. However, the expression pattern of AKAP79/150 in peripheral sensory neurons is unknown. In this study we use immunofluorescence microscopy to identify in DRG sections the peripheral neuron subtypes that express the rodent isoform AKAP150, as well as the subcellular distribution of AKAP150 and its potential target ion channels. We found that AKAP150 is predominantly expressed in a subset of small DRG sensory neurons where it is localized at the plasma membrane of the soma, axon initial segment and small fibers. The majority of these neurons is peripherin positive and produces c-fibers, though a small portion produces Aδ-fibers. Furthermore, we demonstrate that AKAP79/150 colocalizes with TRPV1 and CaV1.2 in the soma and axon initial segment. Thus AKAP150 is expressed in small, nociceptive DRG neurons where it is targeted to membrane regions and where it may play a role in the modulation of ion channel phosphorylation states required for hyperalgesia. PMID:21674494

  8. Differential induction of Toll-like receptors & type 1 interferons by Sabin attenuated & wild type 1 polioviruses in human neuronal cells

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    Madhu C Mohanty

    2013-01-01

    Full Text Available Background & objectives: Polioviruses are the causative agent of paralytic poliomyelitis. Attenuated polioviruses (Sabin oral poliovirus vaccine strains do not replicate efficiently in neurons as compared to the wild type polioviruses and therefore do not cause disease. This study was aimed to investigate the differential host immune response to wild type 1 poliovirus (wild PV and Sabin attenuated type 1 poliovirus (Sabin PV in cultured human neuronal cells. Methods: By using flow cytometry and real time PCR methods we examined host innate immune responses and compared the role of toll like receptors (TLRs and cytoplasmic RNA helicases in cultured human neuronal cells (SK-N-SH infected with Sabin PV and wild PV. Results: Human neuronal cells expressed very low levels of TLRs constitutively. Sabin PV infection induced significantly higher expression of TLR3, TLR7 and melanoma differentiation-associated protein-5 (MDA-5 m-RNA in neuronal cells at the beginning of infection (up to 4 h as compared to wild PV. Further, Sabin PV also induced the expression of interferon α/β at early time point of infection. The induced expression of IFN α/β gene by Sabin PV in neuronal cells could be suppressed by inhibiting TLR7. Interpretation & conclusions: Neuronal cell innate immune response to Sabin and wild polioviruses differ significantly for TLR3, TLR7, MDA5 and type 1 interferons. Effects of TLR7 activation and interferon production and Sabin virus replication in neuronal cells need to be actively investigated in future studies.

  9. POMT1-associated walker-warburg syndrome: a disorder of dendritic development of neocortical neurons.

    Science.gov (United States)

    Judas, M; Sedmak, G; Rados, M; Sarnavka, V; Fumić, K; Willer, T; Gross, C; Hehr, U; Strahl, S; Cuk, M; Barić, I

    2009-02-01

    We have analyzed the morphology and dendritic development of neocortical neurons in a 2.5-month-old infant with Walker-Warburg syndrome homozygotic for a novel POMT1 gene mutation, by Golgi methods. We found that pyramidal neurons frequently displayed abnormal (oblique, horizontal, or inverted) orientation. A novel finding of this study is that members of the same population of pyramidal neurons display different stages of development of their dendritic arborizations: some neurons had poorly developed dendrites and thus resembled pyramidal neurons of the late fetal cortex; for some neurons, the level of differentiation corresponded to that in the newborn cortex; finally, some neurons had quite elaborate dendritic trees as expected for the cortex of 2.5-month-old infant. In addition, apical dendrites of many pyramidal neurons were conspiciously bent to one side, irrespective to the general orientation of the pyramidal neuron. These findings suggest that Walker-Warburg lissencephaly is characterized by two hitherto unnoticed pathogenetic changes in the cerebral cortex: (a) heterochronic decoupling of dendritic maturation within the same neuronal population (with some members significantly lagging behind the normal maturational schedule) and (b) anisotropically distorted shaping of dendritic trees, probably caused by patchy displacement of molecular guidance cues for dendrites in the malformed cortex. Copyright Georg Thieme Verlag KG Stuttgart New York.

  10. RAGE-dependent potentiation of TRPV1 currents in sensory neurons exposed to high glucose.

    Science.gov (United States)

    Lam, Doris; Momeni, Zeinab; Theaker, Michael; Jagadeeshan, Santosh; Yamamoto, Yasuhiko; Ianowski, Juan P; Campanucci, Verónica A

    2018-01-01

    Diabetes mellitus is associated with sensory abnormalities, including exacerbated responses to painful (hyperalgesia) or non-painful (allodynia) stimuli. These abnormalities are symptoms of diabetic peripheral neuropathy (DPN), which is the most common complication that affects approximately 50% of diabetic patients. Yet, the underlying mechanisms linking hyperglycemia and symptoms of DPN remain poorly understood. The transient receptor potential vanilloid 1 (TRPV1) channel plays a central role in such sensory abnormalities and shows elevated expression levels in animal models of diabetes. Here, we investigated the function of TRPV1 channels in sensory neurons cultured from the dorsal root ganglion (DRG) of neonatal mice, under control (5mM) and high glucose (25mM) conditions. After maintaining DRG neurons in high glucose for 1 week, we observed a significant increase in capsaicin (CAP)-evoked currents and CAP-evoked depolarizations, independent of TRPV1 channel expression. These functional changes were largely dependent on the expression of the receptor for Advanced Glycation End-products (RAGE), calcium influx, cytoplasmic ROS accumulation, PKC, and Src kinase activity. Like cultured neurons from neonates, mature neurons from adult mice also displayed a similar potentiation of CAP-evoked currents in the high glucose condition. Taken together, our data demonstrate that under the diabetic condition, DRG neurons are directly affected by elevated levels of glucose, independent of vascular or glial signals, and dependent on RAGE expression. These early cellular and molecular changes to sensory neurons in vitro are potential mechanisms that might contribute to sensory abnormalities that can occur in the very early stages of diabetes.

  11. A chemical-genetic strategy reveals distinct temporal requirements for SAD-1 kinase in neuronal polarization and synapse formation

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    Shokat Kevan M

    2008-09-01

    Full Text Available Abstract Background Neurons assemble into a functional network through a sequence of developmental processes including neuronal polarization and synapse formation. In Caenorhabditis elegans, the serine/threonine SAD-1 kinase is essential for proper neuronal polarity and synaptic organization. To determine if SAD-1 activity regulates the establishment or maintenance of these neuronal structures, we examined its temporal requirements using a chemical-genetic method that allows for selective and reversible inactivation of its kinase activity in vivo. Results We generated a PP1 analog-sensitive variant of SAD-1. Through temporal inhibition of SAD-1 kinase activity we show that its activity is required for the establishment of both neuronal polarity and synaptic organization. However, while SAD-1 activity is needed strictly when neurons are polarizing, the temporal requirement for SAD-1 is less stringent in synaptic organization, which can also be re-established during maintenance. Conclusion This study reports the first temporal analysis of a neural kinase activity using the chemical-genetic system. It reveals that neuronal polarity and synaptic organization have distinct temporal requirements for SAD-1.

  12. Unexpected neuronal protection of SU5416 against 1-Methyl-4-phenylpyridinium ion-induced toxicity via inhibiting neuronal nitric oxide synthase.

    Directory of Open Access Journals (Sweden)

    Wei Cui

    Full Text Available SU5416 was originally designed as a potent and selective inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2 for cancer therapy. In this study, we have found for the first time that SU5416 unexpectedly prevented 1-methyl-4-phenylpyridinium ion (MPP(+-induced neuronal apoptosis in cerebellar granule neurons, and decreased 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP-induced loss of dopaminergic neurons and impairment of swimming behavior in zebrafish in a concentration-dependent manner. However, VEGFR-2 kinase inhibitor II, another specific VEGFR-2 inhibitor, failed to reverse neurotoxicity at the concentration exhibiting anti-angiogenic activity, strongly suggesting that the neuroprotective effect of SU5416 is independent from its anti-angiogenic action. SU5416 potently reversed MPP(+-increased intracellular nitric oxide level with an efficacy similar to 7-nitroindazole, a specific neuronal nitric oxide synthase (nNOS inhibitor. Western blotting analysis showed that SU5416 reduced the elevation of nNOS protein expression induced by MPP(+. Furthermore, SU5416 directly inhibited the enzyme activity of rat cerebellum nNOS with an IC(50 value of 22.7 µM. In addition, knock-down of nNOS expression using short hairpin RNA (shRNA abolished the neuroprotective effects of SU5416 against MPP(+-induced neuronal loss. Our results strongly demonstrate that SU5416 might exert its unexpected neuroprotective effects by concurrently reducing nNOS protein expression and directly inhibiting nNOS enzyme activity. In view of the capability of SU5416 to cross the blood-brain barrier and the safety for human use, our findings further indicate that SU5416 might be a novel drug candidate for neurodegenerative disorders, particularly those associated with NO-mediated neurotoxicity.

  13. Metabolomic profiling reveals a role for CPT1c in neuronal oxidative metabolism

    OpenAIRE

    Lee, Jieun; Wolfgang, Michael J

    2012-01-01

    Abstract Background Carnitine Palmitoyltransferase-1c (CPT1c) is a neuron specific homologue of the carnitine acyltransferase family of enzymes. CPT1 isoenzymes transfer long chain acyl groups to carnitine. This constitutes a rate setting step for mitochondrial fatty acid beta-oxidation by facilitating the initial step in acyl transfer to the mitochondrial matrix. In general, neurons do not heavily utilize fatty acids for bioenergetic needs and definitive enzymatic activity has been unable to...

  14. Reconstruction of phrenic neuron identity in embryonic stem cell-derived motor neurons.

    Science.gov (United States)

    Machado, Carolina Barcellos; Kanning, Kevin C; Kreis, Patricia; Stevenson, Danielle; Crossley, Martin; Nowak, Magdalena; Iacovino, Michelina; Kyba, Michael; Chambers, David; Blanc, Eric; Lieberam, Ivo

    2014-02-01

    Air breathing is an essential motor function for vertebrates living on land. The rhythm that drives breathing is generated within the central nervous system and relayed via specialised subsets of spinal motor neurons to muscles that regulate lung volume. In mammals, a key respiratory muscle is the diaphragm, which is innervated by motor neurons in the phrenic nucleus. Remarkably, relatively little is known about how this crucial subtype of motor neuron is generated during embryogenesis. Here, we used direct differentiation of motor neurons from mouse embryonic stem cells as a tool to identify genes that direct phrenic neuron identity. We find that three determinants, Pou3f1, Hoxa5 and Notch, act in combination to promote a phrenic neuron molecular identity. We show that Notch signalling induces Pou3f1 in developing motor neurons in vitro and in vivo. This suggests that the phrenic neuron lineage is established through a local source of Notch ligand at mid-cervical levels. Furthermore, we find that the cadherins Pcdh10, which is regulated by Pou3f1 and Hoxa5, and Cdh10, which is controlled by Pou3f1, are both mediators of like-like clustering of motor neuron cell bodies. This specific Pcdh10/Cdh10 activity might provide the means by which phrenic neurons are assembled into a distinct nucleus. Our study provides a framework for understanding how phrenic neuron identity is conferred and will help to generate this rare and inaccessible yet vital neuronal subtype directly from pluripotent stem cells, thus facilitating subsequent functional investigations.

  15. Creatine protects against mitochondrial dysfunction associated with HIV-1 Tat-induced neuronal injury

    Science.gov (United States)

    Stevens, Patrick R.; Gawryluk, Jeremy W.; Hui, Liang; Chen, Xuesong; Geiger, Jonathan D.

    2015-01-01

    HIV-1 infected individuals are living longer but experiencing a prevalence rate of over 50% for HIV-1 associated neurocognitive disorders (HAND) for which no effective treatment is available. Viral and cellular factors secreted by HIV-1 infected cells leads to neuronal injury and HIV-1 Tat continues to be implicated in the pathogenesis of HAND. Here we tested the hypothesis that creatine protected against HIV-1 Tat-induced neuronal injury by preventing mitochondrial bioenergetic crisis and/or redox catastrophe. Creatine blocked HIV-1 Tat1-72-induced increases in neuron cell death and synaptic area loss. Creatine protected against HIV-1 Tat-induced decreases in ATP. Creatine and creatine plus HIV-1 Tat increased cellular levels of creatine, and creatine plus HIV-1 Tat further decreased ratios of phosphocreatine to creatine observed with creatine or HIV-1 Tat treatments alone. Additionally, creatine protected against HIV-1 Tat-induced mitochondrial hypopolarization and HIV-1 Tat-induced mitochondrial permeability transition pore opening. Thus, creatine may be a useful adjunctive therapy against HAND. PMID:25613139

  16. Deletion of the Kv2.1 delayed rectifier potassium channel leads to neuronal and behavioral hyperexcitability

    Science.gov (United States)

    Speca, David J.; Ogata, Genki; Mandikian, Danielle; Bishop, Hannah I.; Wiler, Steve W.; Eum, Kenneth; Wenzel, H. Jürgen; Doisy, Emily T.; Matt, Lucas; Campi, Katharine L.; Golub, Mari S.; Nerbonne, Jeanne M.; Hell, Johannes W.; Trainor, Brian C.; Sack, Jon T.; Schwartzkroin, Philip A.; Trimmer, James S.

    2014-01-01

    The Kv2.1 delayed rectifier potassium channel exhibits high-level expression in both principal and inhibitory neurons throughout the central nervous system, including prominent expression in hippocampal neurons. Studies of in vitro preparations suggest that Kv2.1 is a key yet conditional regulator of intrinsic neuronal excitability, mediated by changes in Kv2.1 expression, localization and function via activity-dependent regulation of Kv2.1 phosphorylation. Here we identify neurological and behavioral deficits in mutant (Kv2.1−/−) mice lacking this channel. Kv2.1−/− mice have grossly normal characteristics. No impairment in vision or motor coordination was apparent, although Kv2.1−/− mice exhibit reduced body weight. The anatomic structure and expression of related Kv channels in the brains of Kv2.1−/− mice appears unchanged. Delayed rectifier potassium current is diminished in hippocampal neurons cultured from Kv2.1−/− animals. Field recordings from hippocampal slices of Kv2.1−/− mice reveal hyperexcitability in response to the convulsant bicuculline, and epileptiform activity in response to stimulation. In Kv2.1−/− mice, long-term potentiation at the Schaffer collateral – CA1 synapse is decreased. Kv2.1−/− mice are strikingly hyperactive, and exhibit defects in spatial learning, failing to improve performance in a Morris Water Maze task. Kv2.1−/− mice are hypersensitive to the effects of the convulsants flurothyl and pilocarpine, consistent with a role for Kv2.1 as a conditional suppressor of neuronal activity. Although not prone to spontaneous seizures, Kv2.1−/− mice exhibit accelerated seizure progression. Together, these findings suggest homeostatic suppression of elevated neuronal activity by Kv2.1 plays a central role in regulating neuronal network function. PMID:24494598

  17. Islet-1 is required for ventral neuron survival in Xenopus

    International Nuclear Information System (INIS)

    Shi, Yu; Zhao, Shuhua; Li, Jiejing; Mao, Bingyu

    2009-01-01

    Islet-1 is a LIM domain transcription factor involved in several processes of embryonic development. Xenopus Islet-1 (Xisl-1) has been shown to be crucial for proper heart development. Here we show that Xisl-1 and Xisl-2 are differentially expressed in the nervous system in Xenopus embryos. Knock-down of Xisl-1 by specific morpholino leads to severe developmental defects, including eye and heart failure. Staining with the neuronal markers N-tubulin and Xisl-1 itself reveals that the motor neurons and a group of ventral interneurons are lost in the Xisl-1 morphants. Terminal dUTP nick-end labeling (TUNEL) analysis shows that Xisl-1 morpholino injection induces extensive apoptosis in the ventral neural plate, which can be largely inhibited by the apoptosis inhibitor M50054. We also find that over-expression of Xisl-1 is able to promote cell proliferation and induce Xstat3 expression in the injected side, suggesting a potential role for Xisl-1 in the regulation of cell proliferation in co-operation with the Jak-Stat pathway.

  18. Nonautonomous Regulation of Neuronal Migration by Insulin Signaling, DAF-16/FOXO, and PAK-1

    Directory of Open Access Journals (Sweden)

    Lisa M. Kennedy

    2013-09-01

    Full Text Available Neuronal migration is essential for nervous system development in all organisms and is regulated in the nematode, C. elegans, by signaling pathways that are conserved in humans. Here, we demonstrate that the insulin/IGF-1-PI3K signaling pathway modulates the activity of the DAF-16/FOXO transcription factor to regulate the anterior migrations of the hermaphrodite-specific neurons (HSNs during embryogenesis of C. elegans. When signaling is reduced, DAF-16 is activated and promotes migration; conversely, when signaling is enhanced, DAF-16 is inactivated, and migration is inhibited. We show that DAF-16 acts nonautonomously in the hypodermis to promote HSN migration. Furthermore, we identify PAK-1, a p21-activated kinase, as a downstream mediator of insulin/IGF-1-DAF-16 signaling in the nonautonomous control of HSN migration. Because a FOXO-Pak1 pathway was recently shown to regulate mammalian neuronal polarity, our findings indicate that the roles of FOXO and Pak1 in neuronal migration are most likely conserved from C. elegans to higher organisms.

  19. Spatially tuned normalization explains attention modulation variance within neurons.

    Science.gov (United States)

    Ni, Amy M; Maunsell, John H R

    2017-09-01

    Spatial attention improves perception of attended parts of a scene, a behavioral enhancement accompanied by modulations of neuronal firing rates. These modulations vary in size across neurons in the same brain area. Models of normalization explain much of this variance in attention modulation with differences in tuned normalization across neurons (Lee J, Maunsell JHR. PLoS One 4: e4651, 2009; Ni AM, Ray S, Maunsell JHR. Neuron 73: 803-813, 2012). However, recent studies suggest that normalization tuning varies with spatial location both across and within neurons (Ruff DA, Alberts JJ, Cohen MR. J Neurophysiol 116: 1375-1386, 2016; Verhoef BE, Maunsell JHR. eLife 5: e17256, 2016). Here we show directly that attention modulation and normalization tuning do in fact covary within individual neurons, in addition to across neurons as previously demonstrated. We recorded the activity of isolated neurons in the middle temporal area of two rhesus monkeys as they performed a change-detection task that controlled the focus of spatial attention. Using the same two drifting Gabor stimuli and the same two receptive field locations for each neuron, we found that switching which stimulus was presented at which location affected both attention modulation and normalization in a correlated way within neurons. We present an equal-maximum-suppression spatially tuned normalization model that explains this covariance both across and within neurons: each stimulus generates equally strong suppression of its own excitatory drive, but its suppression of distant stimuli is typically less. This new model specifies how the tuned normalization associated with each stimulus location varies across space both within and across neurons, changing our understanding of the normalization mechanism and how attention modulations depend on this mechanism. NEW & NOTEWORTHY Tuned normalization studies have demonstrated that the variance in attention modulation size seen across neurons from the same cortical

  20. Calcium current homeostasis and synaptic deficits in hippocampal neurons from Kelch-like 1 knockout mice

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    Paula Patricia Perissinotti

    2015-01-01

    Full Text Available Kelch-like 1 (KLHL1 is a neuronal actin-binding protein that modulates voltage-gated CaV2.1 (P/Q-type and CaV3.2 (α1H T-type calcium channels; KLHL1 knockdown experiments (KD cause down-regulation of both channel types and altered synaptic properties in cultured rat hippocampal neurons (Perissinotti et al., 2014. Here, we studied the effect of ablation of KLHL1 on calcium channel function and synaptic properties in cultured hippocampal neurons from KLHL1 knockout (KO mice. Western blot data showed the P/Q-type channel α1A subunit was less abundant in KO hippocampus compared to wildtype (WT; and PQ-type calcium currents were smaller in KO neurons than WT during early days in vitro, although this decrease was compensated for at late stages by increases in L-type calcium current. In contrast, T-type currents did not change in culture. However, biophysical properties and western blot analysis revealed a differential contribution of T-type channel isoforms in the KO, with CaV3.2 α1H subunit being down-regulated and CaV3.1 α1G up-regulated. Synapsin I levels were reduced in the KO hippocampus; cultured neurons displayed a concomitant reduction in synapsin I puncta and decreased miniature excitatory postsynaptic current (mEPSC frequency. In summary, genetic ablation of the calcium channel modulator resulted in compensatory mechanisms to maintain calcium current homeostasis in hippocampal KO neurons; however, synaptic alterations resulted in a reduction of excitatory synapse number, causing an imbalance of the excitatory-inhibitory synaptic input ratio favoring inhibition.

  1. Planar polarity pathway and Nance-Horan syndrome-like 1b have essential cell-autonomous functions in neuronal migration.

    Science.gov (United States)

    Walsh, Gregory S; Grant, Paul K; Morgan, John A; Moens, Cecilia B

    2011-07-01

    Components of the planar cell polarity (PCP) pathway are required for the caudal tangential migration of facial branchiomotor (FBM) neurons, but how PCP signaling regulates this migration is not understood. In a forward genetic screen, we identified a new gene, nhsl1b, required for FBM neuron migration. nhsl1b encodes a WAVE-homology domain-containing protein related to human Nance-Horan syndrome (NHS) protein and Drosophila GUK-holder (Gukh), which have been shown to interact with components of the WAVE regulatory complex that controls cytoskeletal dynamics and with the polarity protein Scribble, respectively. Nhsl1b localizes to FBM neuron membrane protrusions and interacts physically and genetically with Scrib to control FBM neuron migration. Using chimeric analysis, we show that FBM neurons have two modes of migration: one involving interactions between the neurons and their planar-polarized environment, and an alternative, collective mode involving interactions between the neurons themselves. We demonstrate that the first mode of migration requires the cell-autonomous functions of Nhsl1b and the PCP components Scrib and Vangl2 in addition to the non-autonomous functions of Scrib and Vangl2, which serve to polarize the epithelial cells in the environment of the migrating neurons. These results define a role for Nhsl1b as a neuronal effector of PCP signaling and indicate that proper FBM neuron migration is directly controlled by PCP signaling between the epithelium and the migrating neurons.

  2. Neurons other than motor neurons in motor neuron disease.

    Science.gov (United States)

    Ruffoli, Riccardo; Biagioni, Francesca; Busceti, Carla L; Gaglione, Anderson; Ryskalin, Larisa; Gambardella, Stefano; Frati, Alessandro; Fornai, Francesco

    2017-11-01

    Amyotrophic lateral sclerosis (ALS) is typically defined by a loss of motor neurons in the central nervous system. Accordingly, morphological analysis for decades considered motor neurons (in the cortex, brainstem and spinal cord) as the neuronal population selectively involved in ALS. Similarly, this was considered the pathological marker to score disease severity ex vivo both in patients and experimental models. However, the concept of non-autonomous motor neuron death was used recently to indicate the need for additional cell types to produce motor neuron death in ALS. This means that motor neuron loss occurs only when they are connected with other cell types. This concept originally emphasized the need for resident glia as well as non-resident inflammatory cells. Nowadays, the additional role of neurons other than motor neurons emerged in the scenario to induce non-autonomous motor neuron death. In fact, in ALS neurons diverse from motor neurons are involved. These cells play multiple roles in ALS: (i) they participate in the chain of events to produce motor neuron loss; (ii) they may even degenerate more than and before motor neurons. In the present manuscript evidence about multi-neuronal involvement in ALS patients and experimental models is discussed. Specific sub-classes of neurons in the whole spinal cord are reported either to degenerate or to trigger neuronal degeneration, thus portraying ALS as a whole spinal cord disorder rather than a disease affecting motor neurons solely. This is associated with a novel concept in motor neuron disease which recruits abnormal mechanisms of cell to cell communication.

  3. Protective Effect of SGK1 in Rat Hippocampal Neurons Subjected to Ischemia Reperfusion

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    Wei Zhang

    2014-07-01

    Full Text Available Background/Aims: To investigate the protective effect of SGK1 (serum- and glucocorticoid-inducible protein kinase 1 in rat hippocampal neurons in vitro and in vivo following ischemia reperfusion (I/R. Methods: Isolated rat hippocampal neurons were subjected to 2 h of oxygen and glucose deprivation (OGD then returned to normoxic conditions for 10, 30 or 60 min. Cell apoptosis and protein expression of SGK1 were analyzed. To examine SGK1 function, we overexpressed SGK1 in rat hippocampal neurons. Finally we examined the involvement of PI3K/Akt/GSK3β signaling by treating the cells (untransfected or transfected with expression vector encoding SGK1 with the PI3K inhibitor LY294002. Findings were confirmed in vivo in a rat model of middle cerebral artery occlusion. Results: I/R caused a time-dependent increase in apoptosis, both in vitro and in vivo. SGK1 protein levels decreased significantly under the same conditions. Overexpression of SGK1 reduced apoptosis following OGD or I/R compared to cells transfected with empty vector and subjected to the same treatment, or sham-operated animals. Addition of LY294002 revealed that the action of SGK1 in suppressing apoptosis was mediated by the PI3K/Akt/GSK3β pathway. Conclusion: SGK1 plays a protective role in ischemia reperfusion in rat hippocampal neurons, exerting its effects via the PI3K/Akt/GSK3β pathway.

  4. Fibroblast growth factor 10 protects neuron against oxygen–glucose deprivation injury through inducing heme oxygenase-1

    International Nuclear Information System (INIS)

    Li, Yong-Hua; Yang, Li-Ye; Chen, Wei; Li, Ying-Ke; Yuan, Hong-Bin

    2015-01-01

    Highlights: • FGF10 attenuates OGD induced injury in cortical neuron. • FGF10 reduces OGD triggered ROS level in cortical neuron. • FGF10 induces HO-1 expression upon OGD stimuli in cortical neuron. • Knockdown of HO-1 impairs the neuroprotection of FGF10 in OGD model. - Abstract: Fibroblast growth factors (FGFs) are a family of structurally related heparin-binding proteins with diverse biological functions. FGFs participate in mitogenesis, angiogenesis, cell proliferation, development, differentiation and cell migration. Here, we investigated the potential effect of FGF10, a member of FGFs, on neuron survival in oxygen–glucose deprivation (OGD) model. In primary cultured mouse cortical neurons upon OGD, FGF10 treatment (100 and 1000 ng/ml) attenuated the decrease of cell viability and rescued the LDH release. Tuj-1 immunocytochemistry assay showed that FGF10 promoted neuronal survival. Apoptosis assay with Annexin V + PI by flow cytometry demonstrated that FGF10 treatment reduced apoptotic cell proportion. Moreover, immunoblotting showed that FGF10 alleviated the cleaved caspase-3 upregulation caused by OGD. FGF10 treatment also depressed the OGD-induced increase of caspase-3, -8 and -9 activities. At last, we found FGF10 triggered heme oxygenase-1 (HO-1) protein expression rather than hypoxia-inducible factor-1 (HIF-1), AMP-activated protein kinase (AMPK) signaling and extracellular signal-regulated kinases 1/2 (ERK1/2) signaling. Knockdown of HO-1 by siRNA partly abolished the neuroprotection of FGF10 in OGD model. In summary, our observations provide the first evidence for the neuroprotective function of FGF10 against ischemic neuronal injury and suggest that FGF10 may be a promising agent for treatment of ischemic stroke

  5. Fibroblast growth factor 10 protects neuron against oxygen–glucose deprivation injury through inducing heme oxygenase-1

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yong-Hua; Yang, Li-Ye; Chen, Wei; Li, Ying-Ke, E-mail: liyingke6f@126.com; Yuan, Hong-Bin, E-mail: yuanhongbin6f@126.com

    2015-01-02

    Highlights: • FGF10 attenuates OGD induced injury in cortical neuron. • FGF10 reduces OGD triggered ROS level in cortical neuron. • FGF10 induces HO-1 expression upon OGD stimuli in cortical neuron. • Knockdown of HO-1 impairs the neuroprotection of FGF10 in OGD model. - Abstract: Fibroblast growth factors (FGFs) are a family of structurally related heparin-binding proteins with diverse biological functions. FGFs participate in mitogenesis, angiogenesis, cell proliferation, development, differentiation and cell migration. Here, we investigated the potential effect of FGF10, a member of FGFs, on neuron survival in oxygen–glucose deprivation (OGD) model. In primary cultured mouse cortical neurons upon OGD, FGF10 treatment (100 and 1000 ng/ml) attenuated the decrease of cell viability and rescued the LDH release. Tuj-1 immunocytochemistry assay showed that FGF10 promoted neuronal survival. Apoptosis assay with Annexin V + PI by flow cytometry demonstrated that FGF10 treatment reduced apoptotic cell proportion. Moreover, immunoblotting showed that FGF10 alleviated the cleaved caspase-3 upregulation caused by OGD. FGF10 treatment also depressed the OGD-induced increase of caspase-3, -8 and -9 activities. At last, we found FGF10 triggered heme oxygenase-1 (HO-1) protein expression rather than hypoxia-inducible factor-1 (HIF-1), AMP-activated protein kinase (AMPK) signaling and extracellular signal-regulated kinases 1/2 (ERK1/2) signaling. Knockdown of HO-1 by siRNA partly abolished the neuroprotection of FGF10 in OGD model. In summary, our observations provide the first evidence for the neuroprotective function of FGF10 against ischemic neuronal injury and suggest that FGF10 may be a promising agent for treatment of ischemic stroke.

  6. Adrenergic receptors inhibit TRPV1 activity in the dorsal root ganglion neurons of rats.

    Science.gov (United States)

    Matsushita, Yumi; Manabe, Miki; Kitamura, Naoki; Shibuya, Izumi

    2018-01-01

    Transient receptor potential vanilloid type 1 (TRPV1) is a polymodal receptor channel that responds to multiple types of stimuli, such as heat, acid, mechanical pressure and some vanilloids. Capsaicin is the most commonly used vanilloid to stimulate TRPV1. TRPV1 channels are expressed in dorsal root ganglion neurons that extend to Aδ- and C-fibers and have a role in the transduction of noxious inputs to the skin into the electrical signals of the sensory nerve. Although noradrenergic nervous systems, including the descending antinociceptive system and the sympathetic nervous system, are known to modulate pain sensation, the functional association between TRPV1 and noradrenaline in primary sensory neurons has rarely been examined. In the present study, we examined the effects of noradrenaline on capsaicin-evoked currents in cultured dorsal root ganglion neurons of the rat by the whole-cell voltage clamp method. Noradrenaline at concentrations higher than 0.1 pM significantly reduced the amplitudes of the inward capsaicin currents recorded at -60 mV holding potential. This inhibitory action was reversed by either yohimbine (an α2 antagonist, 10 nM) or propranolol (a β antagonist, 10 nM). The α2 agonists, clonidine (1 pM) and dexmedetomidine (1 pM) inhibited capsaicin currents, and yohimbine (1 nM) reversed the effects of clonidine. The inhibitory action of noradrenaline was not seen in the neurons pretreated with pertussis toxin (100 μg/ml for 24 h) and the neurons dialyzed intracellularly with guanosine 5'- [β-thio] diphosphate (GDPβS, 200 μM), the catalytic subunit of protein kinase A (250 U/ml) or okadaic acid (1 μM). These results suggest that noradrenaline directly acts on dorsal root ganglion neurons to inhibit the activity of TRPV1 depending on the activation of α2-adrenoceptors followed by the inhibition of the adenylate cyclase/cAMP/protein kinase A pathway.

  7. Vasculo-Neuronal Coupling: Retrograde Vascular Communication to Brain Neurons.

    Science.gov (United States)

    Kim, Ki Jung; Ramiro Diaz, Juan; Iddings, Jennifer A; Filosa, Jessica A

    2016-12-14

    Continuous cerebral blood flow is essential for neuronal survival, but whether vascular tone influences resting neuronal function is not known. Using a multidisciplinary approach in both rat and mice brain slices, we determined whether flow/pressure-evoked increases or decreases in parenchymal arteriole vascular tone, which result in arteriole constriction and dilation, respectively, altered resting cortical pyramidal neuron activity. We present evidence for intercellular communication in the brain involving a flow of information from vessel to astrocyte to neuron, a direction opposite to that of classic neurovascular coupling and referred to here as vasculo-neuronal coupling (VNC). Flow/pressure increases within parenchymal arterioles increased vascular tone and simultaneously decreased resting pyramidal neuron firing activity. On the other hand, flow/pressure decreases evoke parenchymal arteriole dilation and increased resting pyramidal neuron firing activity. In GLAST-CreERT2; R26-lsl-GCaMP3 mice, we demonstrate that increased parenchymal arteriole tone significantly increased intracellular calcium in perivascular astrocyte processes, the onset of astrocyte calcium changes preceded the inhibition of cortical pyramidal neuronal firing activity. During increases in parenchymal arteriole tone, the pyramidal neuron response was unaffected by blockers of nitric oxide, GABA A , glutamate, or ecto-ATPase. However, VNC was abrogated by TRPV4 channel, GABA B , as well as an adenosine A 1 receptor blocker. Differently to pyramidal neuron responses, increases in flow/pressure within parenchymal arterioles increased the firing activity of a subtype of interneuron. Together, these data suggest that VNC is a complex constitutive active process that enables neurons to efficiently adjust their resting activity according to brain perfusion levels, thus safeguarding cellular homeostasis by preventing mismatches between energy supply and demand. We present evidence for vessel-to-neuron

  8. Resveratrol via sirtuin-1 downregulates RE1-silencing transcription factor (REST) expression preventing PCB-95-induced neuronal cell death.

    Science.gov (United States)

    Guida, Natascia; Laudati, Giusy; Anzilotti, Serenella; Secondo, Agnese; Montuori, Paolo; Di Renzo, Gianfranco; Canzoniero, Lorella M T; Formisano, Luigi

    2015-11-01

    Resveratrol (3,5,4'-trihydroxystilbene) (RSV), a polyphenol widely present in plants, exerts a neuroprotective function in several neurological conditions; it is an activator of class III histone deacetylase sirtuin1 (SIRT1), a crucial regulator in the pathophysiology of neurodegenerative diseases. By contrast, the RE1-silencing transcription factor (REST) is involved in the neurotoxic effects following exposure to polychlorinated biphenyl (PCB) mixture A1254. The present study investigated the effects of RSV-induced activation of SIRT1 on REST expression in SH-SY5Y cells. Further, we investigated the possible relationship between the non-dioxin-like (NDL) PCB-95 and REST through SIRT1 to regulate neuronal death in rat cortical neurons. Our results revealed that RSV significantly decreased REST gene and protein levels in a dose- and time-dependent manner. Interestingly, overexpression of SIRT1 reduced REST expression, whereas EX-527, an inhibitor of SIRT1, increased REST expression and blocked RSV-induced REST downregulation. These results suggest that RSV downregulates REST through SIRT1. In addition, RSV enhanced activator protein 1 (AP-1) transcription factor c-Jun expression and its binding to the REST promoter gene. Indeed, c-Jun knockdown reverted RSV-induced REST downregulation. Intriguingly, in SH-SY5Y cells and rat cortical neurons the NDL PCB-95 induced necrotic cell death in a concentration-dependent manner by increasing REST mRNA and protein expression. In addition, SIRT1 knockdown blocked RSV-induced neuroprotection in rat cortical neurons treated with PCB-95. Collectively, these results indicate that RSV via SIRT1 activates c-Jun, thereby reducing REST expression in SH-SY5Y cells under physiological conditions and blocks PCB-95-induced neuronal cell death by activating the same SIRT1/c-Jun/REST pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Pretreatment with apoaequorin protects hippocampal CA1 neurons from oxygen-glucose deprivation.

    Science.gov (United States)

    Detert, Julia A; Adams, Erin L; Lescher, Jacob D; Lyons, Jeri-Anne; Moyer, James R

    2013-01-01

    Ischemic stroke affects ∼795,000 people each year in the U.S., which results in an estimated annual cost of $73.7 billion. Calcium is pivotal in a variety of neuronal signaling cascades, however, during ischemia, excess calcium influx can trigger excitotoxic cell death. Calcium binding proteins help neurons regulate/buffer intracellular calcium levels during ischemia. Aequorin is a calcium binding protein isolated from the jellyfish Aequorea victoria, and has been used for years as a calcium indicator, but little is known about its neuroprotective properties. The present study used an in vitro rat brain slice preparation to test the hypothesis that an intra-hippocampal infusion of apoaequorin (the calcium binding component of aequorin) protects neurons from ischemic cell death. Bilaterally cannulated rats received an apoaequorin infusion in one hemisphere and vehicle control in the other. Hippocampal slices were then prepared and subjected to 5 minutes of oxygen-glucose deprivation (OGD), and cell death was assayed by trypan blue exclusion. Apoaequorin dose-dependently protected neurons from OGD--doses of 1% and 4% (but not 0.4%) significantly decreased the number of trypan blue-labeled neurons. This effect was also time dependent, lasting up to 48 hours. This time dependent effect was paralleled by changes in cytokine and chemokine expression, indicating that apoaequorin may protect neurons via a neuroimmunomodulatory mechanism. These data support the hypothesis that pretreatment with apoaequorin protects neurons against ischemic cell death, and may be an effective neurotherapeutic.

  10. Resveratrol via sirtuin-1 downregulates RE1-silencing transcription factor (REST) expression preventing PCB-95-induced neuronal cell death

    International Nuclear Information System (INIS)

    Guida, Natascia; Laudati, Giusy; Anzilotti, Serenella; Secondo, Agnese; Montuori, Paolo; Di Renzo, Gianfranco; Canzoniero, Lorella M.T.; Formisano, Luigi

    2015-01-01

    Resveratrol (3,5,4′-trihydroxystilbene) (RSV), a polyphenol widely present in plants, exerts a neuroprotective function in several neurological conditions; it is an activator of class III histone deacetylase sirtuin1 (SIRT1), a crucial regulator in the pathophysiology of neurodegenerative diseases. By contrast, the RE1-silencing transcription factor (REST) is involved in the neurotoxic effects following exposure to polychlorinated biphenyl (PCB) mixture A1254. The present study investigated the effects of RSV-induced activation of SIRT1 on REST expression in SH-SY5Y cells. Further, we investigated the possible relationship between the non-dioxin-like (NDL) PCB-95 and REST through SIRT1 to regulate neuronal death in rat cortical neurons. Our results revealed that RSV significantly decreased REST gene and protein levels in a dose- and time-dependent manner. Interestingly, overexpression of SIRT1 reduced REST expression, whereas EX-527, an inhibitor of SIRT1, increased REST expression and blocked RSV-induced REST downregulation. These results suggest that RSV downregulates REST through SIRT1. In addition, RSV enhanced activator protein 1 (AP-1) transcription factor c-Jun expression and its binding to the REST promoter gene. Indeed, c-Jun knockdown reverted RSV-induced REST downregulation. Intriguingly, in SH-SY5Y cells and rat cortical neurons the NDL PCB-95 induced necrotic cell death in a concentration-dependent manner by increasing REST mRNA and protein expression. In addition, SIRT1 knockdown blocked RSV-induced neuroprotection in rat cortical neurons treated with PCB-95. Collectively, these results indicate that RSV via SIRT1 activates c-Jun, thereby reducing REST expression in SH-SY5Y cells under physiological conditions and blocks PCB-95-induced neuronal cell death by activating the same SIRT1/c-Jun/REST pathway. - Highlights: • Resveratrol via SIRT1/c-Jun downregulates REST mRNA and protein in SH-SY5Y cells. • Non-dioxin-like (NDL) PCB-95 is cytotoxic to

  11. Resveratrol via sirtuin-1 downregulates RE1-silencing transcription factor (REST) expression preventing PCB-95-induced neuronal cell death

    Energy Technology Data Exchange (ETDEWEB)

    Guida, Natascia [IRCSS SDN, Naples 80131 (Italy); Laudati, Giusy [Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, “Federico II” University of Naples, Via Pansini, 5, 80131 Naples (Italy); Anzilotti, Serenella [IRCSS SDN, Naples 80131 (Italy); Secondo, Agnese [Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, “Federico II” University of Naples, Via Pansini, 5, 80131 Naples (Italy); Montuori, Paolo [Department of Public Health, ‘Federico II’ University of Naples, Naples (Italy); Di Renzo, Gianfranco [Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, “Federico II” University of Naples, Via Pansini, 5, 80131 Naples (Italy); Canzoniero, Lorella M.T. [Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, “Federico II” University of Naples, Via Pansini, 5, 80131 Naples (Italy); Division of Pharmacology, Department of Science and Technology, University of Sannio, Via Port' Arsa 11, 82100 Benevento (Italy); Formisano, Luigi, E-mail: cformisa@unisannio.it [Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, “Federico II” University of Naples, Via Pansini, 5, 80131 Naples (Italy); Division of Pharmacology, Department of Science and Technology, University of Sannio, Via Port' Arsa 11, 82100 Benevento (Italy)

    2015-11-01

    Resveratrol (3,5,4′-trihydroxystilbene) (RSV), a polyphenol widely present in plants, exerts a neuroprotective function in several neurological conditions; it is an activator of class III histone deacetylase sirtuin1 (SIRT1), a crucial regulator in the pathophysiology of neurodegenerative diseases. By contrast, the RE1-silencing transcription factor (REST) is involved in the neurotoxic effects following exposure to polychlorinated biphenyl (PCB) mixture A1254. The present study investigated the effects of RSV-induced activation of SIRT1 on REST expression in SH-SY5Y cells. Further, we investigated the possible relationship between the non-dioxin-like (NDL) PCB-95 and REST through SIRT1 to regulate neuronal death in rat cortical neurons. Our results revealed that RSV significantly decreased REST gene and protein levels in a dose- and time-dependent manner. Interestingly, overexpression of SIRT1 reduced REST expression, whereas EX-527, an inhibitor of SIRT1, increased REST expression and blocked RSV-induced REST downregulation. These results suggest that RSV downregulates REST through SIRT1. In addition, RSV enhanced activator protein 1 (AP-1) transcription factor c-Jun expression and its binding to the REST promoter gene. Indeed, c-Jun knockdown reverted RSV-induced REST downregulation. Intriguingly, in SH-SY5Y cells and rat cortical neurons the NDL PCB-95 induced necrotic cell death in a concentration-dependent manner by increasing REST mRNA and protein expression. In addition, SIRT1 knockdown blocked RSV-induced neuroprotection in rat cortical neurons treated with PCB-95. Collectively, these results indicate that RSV via SIRT1 activates c-Jun, thereby reducing REST expression in SH-SY5Y cells under physiological conditions and blocks PCB-95-induced neuronal cell death by activating the same SIRT1/c-Jun/REST pathway. - Highlights: • Resveratrol via SIRT1/c-Jun downregulates REST mRNA and protein in SH-SY5Y cells. • Non-dioxin-like (NDL) PCB-95 is cytotoxic to

  12. High-frequency stimulation-induced peptide release synchronizes arcuate kisspeptin neurons and excites GnRH neurons

    Science.gov (United States)

    Qiu, Jian; Nestor, Casey C; Zhang, Chunguang; Padilla, Stephanie L; Palmiter, Richard D

    2016-01-01

    Kisspeptin (Kiss1) and neurokinin B (NKB) neurocircuits are essential for pubertal development and fertility. Kisspeptin neurons in the hypothalamic arcuate nucleus (Kiss1ARH) co-express Kiss1, NKB, dynorphin and glutamate and are postulated to provide an episodic, excitatory drive to gonadotropin-releasing hormone 1 (GnRH) neurons, the synaptic mechanisms of which are unknown. We characterized the cellular basis for synchronized Kiss1ARH neuronal activity using optogenetics, whole-cell electrophysiology, molecular pharmacology and single cell RT-PCR in mice. High-frequency photostimulation of Kiss1ARH neurons evoked local release of excitatory (NKB) and inhibitory (dynorphin) neuropeptides, which were found to synchronize the Kiss1ARH neuronal firing. The light-evoked synchronous activity caused robust excitation of GnRH neurons by a synaptic mechanism that also involved glutamatergic input to preoptic Kiss1 neurons from Kiss1ARH neurons. We propose that Kiss1ARH neurons play a dual role of driving episodic secretion of GnRH through the differential release of peptide and amino acid neurotransmitters to coordinate reproductive function. DOI: http://dx.doi.org/10.7554/eLife.16246.001 PMID:27549338

  13. Neuronal Rac1 is required for learning-evoked neurogenesis

    DEFF Research Database (Denmark)

    Haditsch, Ursula; Anderson, Matthew P; Freewoman, Julia

    2013-01-01

    Hippocampus-dependent learning and memory relies on synaptic plasticity as well as network adaptations provided by the addition of adult-born neurons. We have previously shown that activity-induced intracellular signaling through the Rho family small GTPase Rac1 is necessary in forebrain projection...

  14. Identification of neural transcription factors required for the differentiation of three neuronal subtypes in the sea urchin embryo.

    Science.gov (United States)

    Slota, Leslie A; McClay, David R

    2018-03-15

    Correct patterning of the nervous system is essential for an organism's survival and complex behavior. Embryologists have used the sea urchin as a model for decades, but our understanding of sea urchin nervous system patterning is incomplete. Previous histochemical studies identified multiple neurotransmitters in the pluteus larvae of several sea urchin species. However, little is known about how, where and when neural subtypes are differentially specified during development. Here, we examine the molecular mechanisms of neuronal subtype specification in 3 distinct neural subtypes in the Lytechinus variegatus larva. We show that these subtypes are specified through Delta/Notch signaling and identify a different transcription factor required for the development of each neural subtype. Our results show achaete-scute and neurogenin are proneural for the serotonergic neurons of the apical organ and cholinergic neurons of the ciliary band, respectively. We also show that orthopedia is not proneural but is necessary for the differentiation of the cholinergic/catecholaminergic postoral neurons. Interestingly, these transcription factors are used similarly during vertebrate neurogenesis. We believe this study is a starting point for building a neural gene regulatory network in the sea urchin and for finding conserved deuterostome neurogenic mechanisms. Copyright © 2018 Elsevier Inc. All rights reserved.

  15. Control of sympathetic vasomotor tone by catecholaminergic C1 neurones of the rostral ventrolateral medulla oblongata

    Science.gov (United States)

    Marina, Nephtali; Abdala, Ana P.L.; Korsak, Alla; Simms, Annabel E.; Allen, Andrew M.; Paton, Julian F.R.; Gourine, Alexander V.

    2011-01-01

    Aims Increased sympathetic tone in obstructive sleep apnoea results from recurrent episodes of systemic hypoxia and hypercapnia and might be an important contributor to the development of cardiovascular disease. In this study, we re-evaluated the role of a specific population of sympathoexcitatory catecholaminergic C1 neurones of the rostral ventrolateral medulla oblongata in the control of sympathetic vasomotor tone, arterial blood pressure, and hypercapnia-evoked sympathetic and cardiovascular responses. Methods and results In anaesthetized rats in vivo and perfused rat working heart brainstem preparations in situ, C1 neurones were acutely silenced by application of the insect peptide allatostatin following cell-specific targeting with a lentiviral vector to express the inhibitory Drosophila allatostatin receptor. In anaesthetized rats with denervated peripheral chemoreceptors, acute inhibition of 50% of the C1 neuronal population resulted in ∼50% reduction in renal sympathetic nerve activity and a profound fall in arterial blood pressure (by ∼25 mmHg). However, under these conditions systemic hypercapnia still evoked vigorous sympathetic activation and the slopes of the CO2-evoked sympathoexcitatory and cardiovascular responses were not affected by inhibition of C1 neurones. Inhibition of C1 neurones in situ resulted in a reversible fall in perfusion pressure and the amplitude of respiratory-related bursts of thoracic sympathetic nerve activity. Conclusion These data confirm a fundamental physiological role of medullary catecholaminergic C1 neurones in maintaining resting sympathetic vasomotor tone and arterial blood pressure. However, C1 neurones do not appear to mediate sympathoexcitation evoked by central actions of CO2. PMID:21543384

  16. CDKL5, a protein associated with rett syndrome, regulates neuronal morphogenesis via Rac1 signaling.

    Science.gov (United States)

    Chen, Qian; Zhu, Yong-Chuan; Yu, Jing; Miao, Sheng; Zheng, Jing; Xu, Li; Zhou, Yang; Li, Dan; Zhang, Chi; Tao, Jiong; Xiong, Zhi-Qi

    2010-09-22

    Mutations in cyclin-dependent kinase-like 5 (CDKL5), also known as serine/threonine kinase 9 (STK9), have been identified in patients with Rett syndrome (RTT) and X-linked infantile spasm. However, the function of CDKL5 in the brain remains unknown. Here, we report that CDKL5 is a critical regulator of neuronal morphogenesis. We identified a neuron-specific splicing variant of CDKL5 whose expression was markedly induced during postnatal development of the rat brain. Downregulating CDKL5 by RNA interference (RNAi) in cultured cortical neurons inhibited neurite growth and dendritic arborization, whereas overexpressing CDKL5 had opposite effects. Furthermore, knocking down CDKL5 in the rat brain by in utero electroporation resulted in delayed neuronal migration, and severely impaired dendritic arborization. In contrast to its proposed function in the nucleus, we found that CDKL5 regulated dendrite development through a cytoplasmic mechanism. In fibroblasts and in neurons, CDKL5 colocalized and formed a protein complex with Rac1, a critical regulator of actin remodeling and neuronal morphogenesis. Overexpression of Rac1 prevented the inhibition of dendrite growth caused by CDKL5 knockdown, and the growth-promoting effect of ectopically expressed CDKL5 on dendrites was abolished by coexpressing a dominant-negative form of Rac1. Moreover, CDKL5 was required for brain-derived neurotrophic factor (BDNF)-induced activation of Rac1. Together, these results demonstrate a critical role of CDKL5 in neuronal morphogenesis and identify a Rho GTPase signaling pathway which may contribute to CDKL5-related disorders.

  17. Bach2 is involved in neuronal differentiation of N1E-115 neuroblastoma cells

    International Nuclear Information System (INIS)

    Shim, Ki Shuk; Rosner, Margit; Freilinger, Angelika; Lubec, Gert; Hengstschlaeger, Markus

    2006-01-01

    Bach1 and Bach2 are evolutionarily related members of the BTB-basic region leucine zipper transcription factor family. We found that Bach2 downregulates cell proliferation of N1E-115 cells and negatively affects their potential to differentiate. Nuclear localization of the cyclin-dependent kinase inhibitor p21 is known to arrest cell cycle progression, and cytoplasmic p21 has been shown to promote neuronal differentiation of N1E-115 cells. We found that ectopic Bach2 causes upregulation of p21 expression in the nucleus and in the cytoplasm in undifferentiated N1E-115 cells. In differentiated cells, Bach2 specifically triggers upregulation of cytoplasmic p21. Our data suggest that Bach2 expression could represent a switch during the process of neuronal differentiation. Bach2 is not expressed in neuronal precursor cells. It would have negative effects on proliferation and differentiation of these cells. In differentiated neuronal cells Bach2 expression is upregulated, which could allow Bach2 to function as a gatekeeper of the differentiated status

  18. Neuronal IFN-beta-induced PI3K/Akt-FoxA1 signalling is essential for generation of FoxA1(+)Treg cells

    DEFF Research Database (Denmark)

    Liu, Yawei; Marin, Andrea; Ejlerskov, Patrick

    2017-01-01

    Neurons reprogramme encephalitogenic T cells (Tenc) to regulatory T cells (Tregs), either FoxP3(+)Tregs or FoxA1(+)Tregs. We reported previously that neuronal ability to generate FoxA1(+)Tregs was central to preventing neuroinflammation in experimental autoimmune encephalomyelitis (EAE). Mice...... lacking interferon (IFN)-β were defective in generating FoxA1(+)Tregs in the brain. Here we show that lack of neuronal IFNβ signalling is associated with the absence of programme death ligand-1 (PDL1), which prevents their ability to reprogramme Tenc cells to FoxA1(+)Tregs. Passive transfer-EAE via IFNβ......-competent Tenc cells to mice lacking IFNβ and active induced-EAE in mice lacking its receptor, IFNAR, in the brain (Nes(Cre):Ifnar(fl/fl)) result in defective FoxA1(+)Tregs generation and aggravated neuroinflammation. IFNβ activates neuronal PI3K/Akt signalling and Akt binds to transcription factor FoxA1...

  19. EAAC1 Gene Deletion Increases Neuronal Death and Blood Brain Barrier Disruption after Transient Cerebral Ischemia in Female Mice

    Directory of Open Access Journals (Sweden)

    Bo Young Choi

    2014-10-01

    Full Text Available EAAC1 is important in modulating brain ischemic tolerance. Mice lacking EAAC1 exhibit increased susceptibility to neuronal oxidative stress in mice after transient cerebral ischemia. EAAC1 was first described as a glutamate transporter but later recognized to also function as a cysteine transporter in neurons. EAAC1-mediated transport of cysteine into neurons contributes to neuronal antioxidant function by providing cysteine substrates for glutathione synthesis. Here we evaluated the effects of EAAC1 gene deletion on hippocampal blood vessel disorganization after transient cerebral ischemia. EAAC1−/− female mice subjected to transient cerebral ischemia by common carotid artery occlusion for 30 min exhibited twice as much hippocampal neuronal death compared to wild-type female mice as well as increased reduction of neuronal glutathione, blood–brain barrier (BBB disruption and vessel disorganization. Pre-treatment of N-acetyl cysteine, a membrane-permeant cysteine prodrug, increased basal glutathione levels in the EAAC1−/− female mice and reduced ischemic neuronal death, BBB disruption and vessel disorganization. These findings suggest that cysteine uptake by EAAC1 is important for neuronal antioxidant function under ischemic conditions.

  20. Differential regulation of the Rac1 GTPase-activating protein (GAP) BCR during oxygen/glucose deprivation in hippocampal and cortical neurons.

    Science.gov (United States)

    Smith, Katharine R; Rajgor, Dipen; Hanley, Jonathan G

    2017-12-08

    Brain ischemia causes oxygen and glucose deprivation (OGD) in neurons, triggering a cascade of events leading to synaptic accumulation of glutamate. Excessive activation of glutamate receptors causes excitotoxicity and delayed cell death in vulnerable neurons. Following global cerebral ischemia, hippocampal CA1 pyramidal neurons are more vulnerable to injury than their cortical counterparts, but the mechanisms that underlie this difference are unclear. Signaling via Rho-family small GTPases, their upstream guanine nucleotide exchange factors, and GTPase-activating proteins (GAPs) is differentially dysregulated in response to OGD/ischemia in hippocampal and cortical neurons. Increased Rac1 activity caused by OGD/ischemia contributes to neuronal death in hippocampal neurons via diverse effects on NADPH oxidase activity and dendritic spine morphology. The Rac1 guanine nucleotide exchange factor Tiam1 mediates an OGD-induced increase in Rac1 activity in hippocampal neurons; however, the identity of an antagonistic GAP remains elusive. Here we show that the Rac1 GAP breakpoint cluster region (BCR) associates with NMDA receptors (NMDARs) along with Tiam1 and that this protein complex is more abundant in hippocampal compared with cortical neurons. Although total BCR is similar in the two neuronal types, BCR is more active in hippocampal compared with cortical neurons. OGD causes an NMDAR- and Ca 2+ -permeable AMPAR-dependent deactivation of BCR in hippocampal but not cortical neurons. BCR knockdown occludes OGD-induced Rac1 activation in hippocampal neurons. Furthermore, disrupting the Tiam1-NMDAR interaction with a fragment of Tiam1 blocks OGD-induced Tiam1 activation but has no effect on the deactivation of BCR. This work identifies BCR as a critical player in Rac1 regulation during OGD in hippocampal neurons. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  1. Labeling of neuronal differentiation and neuron cells with biocompatible fluorescent nanodiamonds.

    Science.gov (United States)

    Hsu, Tzu-Chia; Liu, Kuang-Kai; Chang, Huan-Cheng; Hwang, Eric; Chao, Jui-I

    2014-05-16

    Nanodiamond is a promising carbon nanomaterial developed for biomedical applications. Here, we show fluorescent nanodiamond (FND) with the biocompatible properties that can be used for the labeling and tracking of neuronal differentiation and neuron cells derived from embryonal carcinoma stem (ECS) cells. The fluorescence intensities of FNDs were increased by treatment with FNDs in both the mouse P19 and human NT2/D1 ECS cells. FNDs were taken into ECS cells; however, FNDs did not alter the cellular morphology and growth ability. Moreover, FNDs did not change the protein expression of stem cell marker SSEA-1 of ECS cells. The neuronal differentiation of ECS cells could be induced by retinoic acid (RA). Interestingly, FNDs did not affect on the morphological alteration, cytotoxicity and apoptosis during the neuronal differentiation. Besides, FNDs did not alter the cell viability and the expression of neuron-specific marker β-III-tubulin in these differentiated neuron cells. The existence of FNDs in the neuron cells can be identified by confocal microscopy and flow cytometry. Together, FND is a biocompatible and readily detectable nanomaterial for the labeling and tracking of neuronal differentiation process and neuron cells from stem cells.

  2. Neutralization of LINGO-1 during in vitro differentiation of neural stem cells results in proliferation of immature neurons.

    Directory of Open Access Journals (Sweden)

    Camilla Lööv

    Full Text Available Identifying external factors that can be used to control neural stem cells division and their differentiation to neurons, astrocytes and oligodendrocytes is of high scientific and clinical interest. Here we show that the Nogo-66 receptor interacting protein LINGO-1 is a potent regulator of neural stem cell maturation to neurons. LINGO-1 is expressed by cortical neural stem cells from E14 mouse embryos and inhibition of LINGO-1 during the first days of neural stem cell differentiation results in decreased neuronal maturation. Compared to neurons in control cultures, which after 6 days of differentiation have long extending neurites, neurons in cultures treated with anti-LINGO-1 antibodies retain an immature, round phenotype with only very short processes. Furthermore, neutralization of LINGO-1 results in a threefold increase in βIII tubulin-positive cells compared to untreated control cultures. By using BrdU incorporation assays we show that the immature neurons in LINGO-1 neutralized cultures are dividing neuroblasts. In contrast to control cultures, in which no cells were double positive for βIII tubulin and BrdU, 36% of the neurons in cultures treated with anti-LINGO-1 antibodies were proliferating after three days of differentiation. TUNEL assays revealed that the amount of cells going through apoptosis during the early phase of differentiation was significantly decreased in cultures treated with anti-LINGO-1 antibodies compared to untreated control cultures. Taken together, our results demonstrate a novel role for LINGO-1 in neural stem cell differentiation to neurons and suggest a possibility to use LINGO-1 inhibitors to compensate for neuronal cell loss in the injured brain.

  3. Coherence resonance in globally coupled neuronal networks with different neuron numbers

    International Nuclear Information System (INIS)

    Ning Wei-Lian; Zhang Zheng-Zhen; Zeng Shang-You; Luo Xiao-Shu; Hu Jin-Lin; Zeng Shao-Wen; Qiu Yi; Wu Hui-Si

    2012-01-01

    Because a brain consists of tremendous neuronal networks with different neuron numbers ranging from tens to tens of thousands, we study the coherence resonance due to ion channel noises in globally coupled neuronal networks with different neuron numbers. We confirm that for all neuronal networks with different neuron numbers there exist the array enhanced coherence resonance and the optimal synaptic conductance to cause the maximal spiking coherence. Furthermoremore, the enhancement effects of coupling on spiking coherence and on optimal synaptic conductance are almost the same, regardless of the neuron numbers in the neuronal networks. Therefore for all the neuronal networks with different neuron numbers in the brain, relative weak synaptic conductance (0.1 mS/cm 2 ) is sufficient to induce the maximal spiking coherence and the best sub-threshold signal encoding. (interdisciplinary physics and related areas of science and technology)

  4. Lung inflammation induces IL-1β expression in hypoglossal neurons in rat brainstem

    Science.gov (United States)

    Jafri, Anjum; Belkadi, Abdelmadjid; Zaidi, Syed I. A.; Getsy, Paulina; Wilson, Christopher G.; Martin, Richard J.

    2013-01-01

    Perinatal inflammation is associated with respiratory morbidity. Immune modulation of brainstem respiratory control centers may provide a link for this pathobiology. We exposed 11-day old rats to intratracheal lipopolysaccharide (LPS, 0.5 µg/g) to test the hypothesis that intrapulmonary inflammation increases expression of the proinflammatory cytokine IL-1β within respiratory-related brainstem regions. Intratracheal LPS resulted in a 32% increase in IL-1β protein expression in the medulla oblongata. In situ hybridization showed increased intensity of IL-1β mRNA but no change in neuronal numbers. Co-localization experiments showed that hypoglossal neurons express IL-1β mRNA and immunostaining showed a 43% increase in IL-1β protein-expressing cells after LPS exposure. LPS treatment also significantly increased microglial cell numbers though they did not express IL-1β mRNA. LPS-induced brainstem expression of neuronal IL-1β mRNA and protein may have implications for our understanding of the vulnerability of neonatal respiratory control in response to a peripheral pro-inflammatory stimulus. PMID:23648475

  5. Subgroup-Elimination Transcriptomics Identifies Signaling Proteins that Define Subclasses of TRPV1-Positive Neurons and a Novel Paracrine Circuit

    Science.gov (United States)

    Isensee, Jörg; Wenzel, Carsten; Buschow, Rene; Weissmann, Robert; Kuss, Andreas W.; Hucho, Tim

    2014-01-01

    Normal and painful stimuli are detected by specialized subgroups of peripheral sensory neurons. The understanding of the functional differences of each neuronal subgroup would be strongly enhanced by knowledge of the respective subgroup transcriptome. The separation of the subgroup of interest, however, has proven challenging as they can hardly be enriched. Instead of enriching, we now rapidly eliminated the subgroup of neurons expressing the heat-gated cation channel TRPV1 from dissociated rat sensory ganglia. Elimination was accomplished by brief treatment with TRPV1 agonists followed by the removal of compromised TRPV1(+) neurons using density centrifugation. By differential microarray and sequencing (RNA-Seq) based expression profiling we compared the transcriptome of all cells within sensory ganglia versus the same cells lacking TRPV1 expressing neurons, which revealed 240 differentially expressed genes (adj. p1.5). Corroborating the specificity of the approach, many of these genes have been reported to be involved in noxious heat or pain sensitization. Beyond the expected enrichment of ion channels, we found the TRPV1 transcriptome to be enriched for GPCRs and other signaling proteins involved in adenosine, calcium, and phosphatidylinositol signaling. Quantitative population analysis using a recent High Content Screening (HCS) microscopy approach identified substantial heterogeneity of expressed target proteins even within TRPV1-positive neurons. Signaling components defined distinct further subgroups within the population of TRPV1-positive neurons. Analysis of one such signaling system showed that the pain sensitizing prostaglandin PGD2 activates DP1 receptors expressed predominantly on TRPV1(+) neurons. In contrast, we found the PGD2 producing prostaglandin D synthase to be expressed exclusively in myelinated large-diameter neurons lacking TRPV1, which suggests a novel paracrine neuron-neuron communication. Thus, subgroup analysis based on the elimination

  6. Hindbrain Catecholamine Neurons Activate Orexin Neurons During Systemic Glucoprivation in Male Rats.

    Science.gov (United States)

    Li, Ai-Jun; Wang, Qing; Elsarelli, Megan M; Brown, R Lane; Ritter, Sue

    2015-08-01

    Hindbrain catecholamine neurons are required for elicitation of feeding responses to glucose deficit, but the forebrain circuitry required for these responses is incompletely understood. Here we examined interactions of catecholamine and orexin neurons in eliciting glucoprivic feeding. Orexin neurons, located in the perifornical lateral hypothalamus (PeFLH), are heavily innervated by hindbrain catecholamine neurons, stimulate food intake, and increase arousal and behavioral activation. Orexin neurons may therefore contribute importantly to appetitive responses, such as food seeking, during glucoprivation. Retrograde tracing results showed that nearly all innervation of the PeFLH from the hindbrain originated from catecholamine neurons and some raphe nuclei. Results also suggested that many catecholamine neurons project collaterally to the PeFLH and paraventricular hypothalamic nucleus. Systemic administration of the antiglycolytic agent, 2-deoxy-D-glucose, increased food intake and c-Fos expression in orexin neurons. Both responses were eliminated by a lesion of catecholamine neurons innervating orexin neurons using the retrogradely transported immunotoxin, anti-dopamine-β-hydroxylase saporin, which is specifically internalized by dopamine-β-hydroxylase-expressing catecholamine neurons. Using designer receptors exclusively activated by designer drugs in transgenic rats expressing Cre recombinase under the control of tyrosine hydroxylase promoter, catecholamine neurons in cell groups A1 and C1 of the ventrolateral medulla were activated selectively by peripheral injection of clozapine-N-oxide. Clozapine-N-oxide injection increased food intake and c-Fos expression in PeFLH orexin neurons as well as in paraventricular hypothalamic nucleus neurons. In summary, catecholamine neurons are required for the activation of orexin neurons during glucoprivation. Activation of orexin neurons may contribute to appetitive responses required for glucoprivic feeding.

  7. Curcumin protects microglia and primary rat cortical neurons against HIV-1 gp120-mediated inflammation and apoptosis.

    Directory of Open Access Journals (Sweden)

    Luyan Guo

    Full Text Available Curcumin is a molecule found in turmeric root that has anti-inflammatory, antioxidant, and anti-tumor properties and has been widely used as both an herbal drug and a food additive to treat or prevent neurodegenerative diseases. To explore whether curcumin is able to ameliorate HIV-1-associated neurotoxicity, we treated a murine microglial cell line (N9 and primary rat cortical neurons with curcumin in the presence or absence of neurotoxic HIV-1 gp120 (V3 loop protein. We found that HIV-1 gp120 profoundly induced N9 cells to produce reactive oxygen species (ROS, tumor necrosis factor-α (TNF-α and monocyte chemoattractant protein-1 (MCP-1. HIV-1 gp120 also induced apoptosis of primary rat cortical neurons. Curcumin exerted a powerful inhibitory effect against HIV-1 gp120-induced neuronal damage, reducing the production of ROS, TNF-α and MCP-1 by N9 cells and inhibiting apoptosis of primary rat cortical neurons. Curcumin may exert its biological activities through inhibition of the delayed rectification and transient outward potassium (K(+ current, as curcumin effectively reduced HIV-1 gp120-mediated elevation of the delayed rectification and transient outward K(+ channel current in neurons. We conclude that HIV-1 gp120 increases ROS, TNF-α and MCP-1 production in microglia, and induces cortical neuron apoptosis by affecting the delayed rectification and transient outward K(+ channel current. Curcumin reduces production of ROS and inflammatory mediators in HIV-1-gp120-stimulated microglia, and protects cortical neurons against HIV-1-mediated apoptosis, most likely through inhibition of HIV-1 gp120-induced elevation of the delayed rectification and transient outward K(+ current.

  8. The Intrinsic Electrophysiological Properties of Mammalian Neurons: Insights into Central Nervous System Function

    Science.gov (United States)

    Llinas, Rodolfo R.

    1988-12-01

    This article reviews the electroresponsive properties of single neurons in the mammalian central nervous system (CNS). In some of these cells the ionic conductances responsible for their excitability also endow them with autorhythmic electrical oscillatory properties. Chemical or electrical synaptic contacts between these neurons often result in network oscillations. In such networks, autorhytmic neurons may act as true oscillators (as pacemakers) or as resonators (responding preferentially to certain firing frequencies). Oscillations and resonance in the CNS are proposed to have diverse functional roles, such as (i) determining global functional states (for example, sleep-wakefulness or attention), (ii) timing in motor coordination, and (iii) specifying connectivity during development. Also, oscillation, especially in the thalamo-cortical circuits, may be related to certain neurological and psychiatric disorders. This review proposes that the autorhythmic electrical properties of central neurons and their connectivity form the basis for an intrinsic functional coordinate system that provides internal context to sensory input.

  9. Histamine induces microglia activation and dopaminergic neuronal toxicity via H1 receptor activation.

    Science.gov (United States)

    Rocha, Sandra M; Saraiva, Tatiana; Cristóvão, Ana C; Ferreira, Raquel; Santos, Tiago; Esteves, Marta; Saraiva, Cláudia; Je, Goun; Cortes, Luísa; Valero, Jorge; Alves, Gilberto; Klibanov, Alexander; Kim, Yoon-Seong; Bernardino, Liliana

    2016-06-04

    Histamine is an amine widely known as a peripheral inflammatory mediator and as a neurotransmitter in the central nervous system. Recently, it has been suggested that histamine acts as an innate modulator of microglial activity. Herein, we aimed to disclose the role of histamine in microglial phagocytic activity and reactive oxygen species (ROS) production and to explore the consequences of histamine-induced neuroinflammation in dopaminergic (DA) neuronal survival. The effect of histamine on phagocytosis was assessed both in vitro by using a murine N9 microglial cell line and primary microglial cell cultures and in vivo. Cells were exposed to IgG-opsonized latex beads or phosphatidylserine (PS) liposomes to evaluate Fcγ or PS receptor-mediated microglial phagocytosis, respectively. ROS production and protein levels of NADPH oxidases and Rac1 were assessed as a measure of oxidative stress. DA neuronal survival was evaluated in vivo by counting the number of tyrosine hydroxylase-positive neurons in the substantia nigra (SN) of mice. We found that histamine triggers microglial phagocytosis via histamine receptor 1 (H1R) activation and ROS production via H1R and H4R activation. By using apocynin, a broad NADPH oxidase (Nox) inhibitor, and Nox1 knockout mice, we found that the Nox1 signaling pathway is involved in both phagocytosis and ROS production induced by histamine in vitro. Interestingly, both apocynin and annexin V (used as inhibitor of PS-induced phagocytosis) fully abolished the DA neurotoxicity induced by the injection of histamine in the SN of adult mice in vivo. Blockade of H1R protected against histamine-induced Nox1 expression and death of DA neurons in vivo. Overall, our results highlight the relevance of histamine in the modulation of microglial activity that ultimately may interfere with neuronal survival in the context of Parkinson's disease (PD) and, eventually, other neurodegenerative diseases which are accompanied by microglia

  10. Xbp1s in Pomc neurons connects ER stress with energy balance and glucose homeostasis

    Science.gov (United States)

    The molecular mechanisms underlying neuronal leptin and insulin resistance in obesity and diabetes remain unclear. Here we show that induction ofthe unfolded protein response transcription factor spliced X-box binding protein 1(Xbp1s) in pro-opio-melanocortin (Pomc) neurons alone is sufficient to pr...

  11. Evidence that OGG1 glycosylase protects neurons against oxidative DNA damage and cell death under ischemic conditions

    DEFF Research Database (Denmark)

    Liu, Dong; Croteau, Deborah L; Souza-Pinto, Nadja

    2011-01-01

    to ischemic and oxidative stress. After exposure of cultured neurons to oxidative and metabolic stress levels of OGG1 in the nucleus were elevated and mitochondria exhibited fragmentation and increased levels of the mitochondrial fission protein dynamin-related protein 1 (Drp1) and reduced membrane potential......7,8-Dihydro-8-oxoguanine DNA glycosylase (OGG1) is a major DNA glycosylase involved in base-excision repair (BER) of oxidative DNA damage to nuclear and mitochondrial DNA (mtDNA). We used OGG1-deficient (OGG1(-/-)) mice to examine the possible roles of OGG1 in the vulnerability of neurons....... Cortical neurons isolated from OGG1(-/-) mice were more vulnerable to oxidative insults than were OGG1(+/+) neurons, and OGG1(-/-) mice developed larger cortical infarcts and behavioral deficits after permanent middle cerebral artery occlusion compared with OGG1(+/+) mice. Accumulations of oxidative DNA...

  12. MONOMERIC ß-AMYLOID INTERACTS WITH TYPE-1 INSULIN-LIKE GROWTH FACTOR RECEPTORS TO PROVIDE ENERGY SUPPLY TO NEURONS

    Directory of Open Access Journals (Sweden)

    Maria Laura eGiuffrida

    2015-08-01

    Full Text Available ß-amyloid (Aß1-42 is produced by proteolytic cleavage of the transmembrane type-1 protein, amyloid precursor protein. Under pathological conditions, Aß1-42 self-aggregates into oligomers, which cause synaptic dysfunction and neuronal loss, and are considered the culprit of Alzheimer’s disease (AD. However, Aß1-42 is mainly monomeric at physiological concentrations, and the precise role of monomeric Aß1-42 in neuronal function is largely unknown. We report that the monomer of Aß1-42 activates type-1 insulin-like growth factor receptors and enhances glucose uptake in neurons and peripheral cells by promoting the translocation of the Glut3 glucose transporter from the cytosol to the plasma membrane. In neurons, activity-dependent glucose uptake was blunted after blocking endogenous Aß production, and re-established in the presence of cerebrospinal fluid Aß. APP-null neurons failed to enhance depolarization-stimulated glucose uptake unless exogenous monomeric Aß1-42 was added. These data suggest that Aß1-42 monomers were critical for maintaining neuronal glucose homeostasis. Accordingly, exogenous Aß1-42 monomers were able to rescue the low levels of glucose consumption observed in brain slices from AD mutant mice.

  13. [Effect of electromagnetic radiation on discharge activity of neurons in the hippocampus CA1 in rats].

    Science.gov (United States)

    Tong, Jun; Chen, Su; Liu, Xiang-Ming; Hao, Dong-Mei

    2013-09-01

    In order to explore effect of electromagnetic radiation on learning and memory ability of hippocampus neuron in rats, the changes in discharge patterns and overall electrical activity of hippocampus neuron after electromagnetic radiation were observed. Rat neurons discharge was recorded with glass electrode extracellular recording technology and a polygraph respectively. Radiation frequency of electromagnetic wave was 900 MHZ and the power was 10 W/m2. In glass electrode extracellular recording, the rats were separately irradiated for 10, 20, 30, 40, 50 and 60 min, every points repeated 10 times and updated interval of 1h, observing the changes in neuron discharge and spontaneous discharge patterns after electromagnetic radiation. In polygraph recording experiments, irradiation group rats for five days a week, 6 hours per day, repeatedly for 10 weeks, memory electrical changes in control group and irradiation group rats when they were feeding were repeatedly monitored by the implanted electrodes, observing the changes in peak electric digits and the largest amplitude in hippocampal CA1 area, and taking some electromagnetic radiation sampling sequence for correlation analysis. (1) Electromagnetic radiation had an inhibitory role on discharge frequency of the hippocampus CA1 region neurons. After electromagnetic radiation, discharge frequency of the hippocampus CA1 region neurons was reduced, but the changes in scale was not obvious. (2) Electromagnetic radiation might change the spontaneous discharge patterns of hippocampus CA1 region neurons, which made the explosive discharge pattern increased obviously. (3) Peak potential total number within 5 min in irradiation group was significantly reduced, the largest amplitude was less than that of control group. (4) Using mathematical method to make the correlation analysis of the electromagnetic radiation sampling sequence, that of irradiation group was less than that of control group, indicating that there was a tending

  14. Hippocampal Neuron Number Is Unchanged 1 Year After Fractionated Whole-Brain Irradiation at Middle Age

    International Nuclear Information System (INIS)

    Shi Lei; Molina, Doris P.; Robbins, Michael E.; Wheeler, Kenneth T.; Brunso-Bechtold, Judy K.

    2008-01-01

    Purpose: To determine whether hippocampal neurons are lost 12 months after middle-aged rats received a fractionated course of whole-brain irradiation (WBI) that is expected to be biologically equivalent to the regimens used clinically in the treatment of brain tumors. Methods and Materials: Twelve-month-old Fischer 344 X Brown Norway male rats were divided into WBI and control (CON) groups (n = 6 per group). Anesthetized WBI rats received 45 Gy of 137 Cs γ rays delivered as 9 5-Gy fractions twice per week for 4.5 weeks. Control rats were anesthetized but not irradiated. Twelve months after WBI completion, all rats were anesthetized and perfused with paraformaldehyde, and hippocampal sections were immunostained with the neuron-specific antibody NeuN. Using unbiased stereology, total neuron number and the volume of the neuronal and neuropil layers were determined in the dentate gyrus, CA3, and CA1 subregions of hippocampus. Results: No differences in tissue integrity or neuron distribution were observed between the WBI and CON groups. Moreover, quantitative analysis demonstrated that neither total neuron number nor the volume of neuronal or neuropil layers differed between the two groups for any subregion. Conclusions: Impairment on a hippocampal-dependent learning and memory test occurs 1 year after fractionated WBI at middle age. The same WBI regimen, however, does not lead to a loss of neurons or a reduction in the volume of hippocampus

  15. Neurons from the adult human dentate nucleus: neural networks in the neuron classification.

    Science.gov (United States)

    Grbatinić, Ivan; Marić, Dušica L; Milošević, Nebojša T

    2015-04-07

    Topological (central vs. border neuron type) and morphological classification of adult human dentate nucleus neurons according to their quantified histomorphological properties using neural networks on real and virtual neuron samples. In the real sample 53.1% and 14.1% of central and border neurons, respectively, are classified correctly with total of 32.8% of misclassified neurons. The most important result present 62.2% of misclassified neurons in border neurons group which is even greater than number of correctly classified neurons (37.8%) in that group, showing obvious failure of network to classify neurons correctly based on computational parameters used in our study. On the virtual sample 97.3% of misclassified neurons in border neurons group which is much greater than number of correctly classified neurons (2.7%) in that group, again confirms obvious failure of network to classify neurons correctly. Statistical analysis shows that there is no statistically significant difference in between central and border neurons for each measured parameter (p>0.05). Total of 96.74% neurons are morphologically classified correctly by neural networks and each one belongs to one of the four histomorphological types: (a) neurons with small soma and short dendrites, (b) neurons with small soma and long dendrites, (c) neuron with large soma and short dendrites, (d) neurons with large soma and long dendrites. Statistical analysis supports these results (pneurons can be classified in four neuron types according to their quantitative histomorphological properties. These neuron types consist of two neuron sets, small and large ones with respect to their perykarions with subtypes differing in dendrite length i.e. neurons with short vs. long dendrites. Besides confirmation of neuron classification on small and large ones, already shown in literature, we found two new subtypes i.e. neurons with small soma and long dendrites and with large soma and short dendrites. These neurons are

  16. Neurochemical and toxic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and 1-methyl-4-phenylpyridine to rat serotonin neurons in dissociated cell cultures

    International Nuclear Information System (INIS)

    Friedman, L.K.; Mytilineou, C.

    1990-01-01

    Dissociated cell cultures from the pontine area of embryonic rat brain were used to study the sensitivity of serotonin (5-hydroxy-tryptamine (5-HT)) neurons to the neurotoxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridine (MPP+). Treatment with MPTP (up to 100 microM) for 7 days did not cause degeneration of 5-HT neurons. A 50% inhibition of [3H]5-HT uptake caused by 100 microM MPTP was a direct effect on the 5-HT uptake carrier, reversed by washing for 7 days. Incubation of cultures with MPTP increased the intraneuronal levels of 5-HT and reduced the levels of 5-hydroxyindoleacetic acid, suggesting a reduction in 5-HT metabolism. MPTP reduced monoamine oxidase activity in the cultures, which probably led to the reduction in 5-HT metabolism. Exposure to MPP+ (0.5-10 microM) for 4 to 7 days decreased [3H]5-HT uptake and induced loss of neurons stained with antibodies against 5-HT. Comparison between 5-HT and dopamine (DA) neurons indicated a differential sensitivity to MPP+ toxicity with DA neurons being more susceptible. Analysis of the competition of MPP+ with the natural substrates for uptake sites of 5-HT and DA neurons demonstrated higher affinity of MPP+ for DA compared to 5-HT neurons. The lower affinity of MPP+ for 5-HT neurons could be responsible for the accumulation of lower MPP+ levels observed in pontine cultures and explain the resistance of 5-HT neurons to this toxin

  17. Neuron-specific caveolin-1 overexpression improves motor function and preserves memory in mice subjected to brain trauma.

    Science.gov (United States)

    Egawa, Junji; Schilling, Jan M; Cui, Weihua; Posadas, Edmund; Sawada, Atsushi; Alas, Basheer; Zemljic-Harpf, Alice E; Fannon-Pavlich, McKenzie J; Mandyam, Chitra D; Roth, David M; Patel, Hemal H; Patel, Piyush M; Head, Brian P

    2017-08-01

    Studies in vitro and in vivo demonstrate that membrane/lipid rafts and caveolin (Cav) organize progrowth receptors, and, when overexpressed specifically in neurons, Cav-1 augments neuronal signaling and growth and improves cognitive function in adult and aged mice; however, whether neuronal Cav-1 overexpression can preserve motor and cognitive function in the brain trauma setting is unknown. Here, we generated a neuron-targeted Cav-1-overexpressing transgenic (Tg) mouse [synapsin-driven Cav-1 (SynCav1 Tg)] and subjected it to a controlled cortical impact model of brain trauma and measured biochemical, anatomic, and behavioral changes. SynCav1 Tg mice exhibited increased hippocampal expression of Cav-1 and membrane/lipid raft localization of postsynaptic density protein 95, NMDA receptor, and tropomyosin receptor kinase B. When subjected to a controlled cortical impact, SynCav1 Tg mice demonstrated preserved hippocampus-dependent fear learning and memory, improved motor function recovery, and decreased brain lesion volume compared with wild-type controls. Neuron-targeted overexpression of Cav-1 in the adult brain prevents hippocampus-dependent learning and memory deficits, restores motor function after brain trauma, and decreases brain lesion size induced by trauma. Our findings demonstrate that neuron-targeted Cav-1 can be used as a novel therapeutic strategy to restore brain function and prevent trauma-associated maladaptive plasticity.-Egawa, J., Schilling, J. M., Cui, W., Posadas, E., Sawada, A., Alas, B., Zemljic-Harpf, A. E., Fannon-Pavlich, M. J., Mandyam, C. D., Roth, D. M., Patel, H. H., Patel, P. M., Head, B. P. Neuron-specific caveolin-1 overexpression improves motor function and preserves memory in mice subjected to brain trauma. © FASEB.

  18. Innervation by a GABAergic neuron depresses spontaneous release in glutamatergic neurons and unveils the clamping phenotype of synaptotagmin-1

    DEFF Research Database (Denmark)

    Wierda, Keimpe D B; Sørensen, Jakob Balslev

    2014-01-01

    The role of spontaneously occurring release events in glutamatergic and GABAergic neurons and their regulation is intensely debated. To study the interdependence of glutamatergic and GABAergic spontaneous release, we compared reciprocally connected "mixed" glutamatergic/GABAergic neuronal pairs...... from mice cultured on astrocyte islands with "homotypic" glutamatergic or GABAergic pairs and autaptic neurons. We measured mEPSC and mIPSC frequencies simultaneously from both neurons. Neuronal pairs formed both interneuronal synaptic and autaptic connections indiscriminately. We find that whereas m......EPSC and mIPSC frequencies did not deviate between autaptic and synaptic connections, the frequency of mEPSCs in mixed pairs was strongly depressed compared with either autaptic neurons or glutamatergic pairs. Simultaneous imaging of synapses, or comparison to evoked release amplitudes, showed...

  19. Deletion or Inhibition of the Oxygen Sensor PHD1 Protects against Ischemic Stroke via Reprogramming of Neuronal Metabolism.

    Science.gov (United States)

    Quaegebeur, Annelies; Segura, Inmaculada; Schmieder, Roberta; Verdegem, Dries; Decimo, Ilaria; Bifari, Francesco; Dresselaers, Tom; Eelen, Guy; Ghosh, Debapriva; Davidson, Shawn M; Schoors, Sandra; Broekaert, Dorien; Cruys, Bert; Govaerts, Kristof; De Legher, Carla; Bouché, Ann; Schoonjans, Luc; Ramer, Matt S; Hung, Gene; Bossaert, Goele; Cleveland, Don W; Himmelreich, Uwe; Voets, Thomas; Lemmens, Robin; Bennett, C Frank; Robberecht, Wim; De Bock, Katrien; Dewerchin, Mieke; Ghesquière, Bart; Fendt, Sarah-Maria; Carmeliet, Peter

    2016-02-09

    The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network. Instead, PHD1(-/-) neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1(-/-) neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose away from glycolysis. As a result, PHD1(-/-) neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Brain pericyte-derived soluble factors enhance insulin sensitivity in GT1-7 hypothalamic neurons.

    Science.gov (United States)

    Takahashi, Hiroyuki; Takata, Fuyuko; Matsumoto, Junichi; Machida, Takashi; Yamauchi, Atsushi; Dohgu, Shinya; Kataoka, Yasufumi

    2015-02-20

    Insulin signaling in the hypothalamus plays an important role in food intake and glucose homeostasis. Hypothalamic neuronal functions are modulated by glial cells; these form an extensive network connecting the neurons and cerebral vasculature, known as the neurovascular unit (NVU). Brain pericytes are periendothelial accessory structures of the blood-brain barrier and integral members of the NVU. However, the interaction between pericytes and neurons is largely unexplored. Here, we investigate whether brain pericytes could affect hypothalamic neuronal insulin signaling. Our immunohistochemical observations demonstrated the existence of pericytes in the mouse hypothalamus, exhibiting immunoreactivity of platelet-derived growth factor receptor β (a pericyte marker), and laminin, a basal lamina marker. We then exposed a murine hypothalamic neuronal cell line, GT1-7, to conditioned medium obtained from primary cultures of rat brain pericytes. Pericyte-conditioned medium (PCM), but not astrocyte- or aortic smooth muscle cell-conditioned medium, increased the insulin-stimulated phosphorylation of Akt in GT1-7 cells in a concentration-dependent manner. PCM also enhanced insulin-stimulated tyrosine phosphorylation of insulin receptor β without changing its expression or localization in cytosolic or plasma membrane fractions. These results suggest that pericytes, rather than astrocytes, increase insulin sensitivity in hypothalamic neurons by releasing soluble factors under physiological conditions in the NVU. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Non-autonomous Regulation of Neuronal Migration by Insulin Signaling, DAF-16/FOXO and PAK-1

    Science.gov (United States)

    Kennedy, Lisa M.; Pham, Steven C.D.L.; Grishok, Alla

    2013-01-01

    SUMMARY Neuronal migration is essential for nervous system development in all organisms and is regulated in the nematode, C. elegans, by signaling pathways that are conserved in humans. Here, we demonstrate that the Insulin/IGF-1-PI3K signaling pathway modulates the activity of the DAF-16/FOXO transcription factor to promote the anterior migrations of the hermaphrodite-specific neurons (HSNs) during embryogenesis of C. elegans. When signaling is reduced, DAF-16 is activated and promotes migration, conversely, when signaling is enhanced, DAF-16 is inactivated and migration is inhibited. We show that DAF-16 acts non-autonomously in the hypodermis to promote HSN migration. Furthermore, we identify PAK-1, a p21-activated kinase, as a downstream mediator of Insulin/IGF-1-DAF-16 signaling in the non-autonomous control of HSN migration. As a FOXO-Pak1 pathway was recently shown to regulate mammalian neuronal polarity, our findings indicate that the roles of FOXO and Pak1 in neuronal migration are likely conserved from C. elegans to higher organisms. PMID:23994474

  2. What do we really know about 5-HT1A receptor signaling in neuronal cells?

    Directory of Open Access Journals (Sweden)

    JENNY LUCY FIEDLER

    2016-11-01

    Full Text Available Serotonin (5-HT is a neurotransmitter that plays an important role in neuronal plasticity. Variations in the levels of 5-HT at the synaptic cleft, expression or dysfunction of serotonin receptors may alter brain development and predispose to various mental diseases. Here, we review the transduction pathways described in various cell types transfected with recombinant 5-HT1A receptor (5-HT1AR, specially contrasting with those findings obtained in neuronal cells. The 5-HT1AR is detected in early stages of neural development and is located in the soma, dendrites and spines of hippocampal neurons. The 5-HT1AR differs from other serotonin receptors because it is coupled to different pathways, depending on the targeted cell. The signaling pathway associated with this receptor is determined by Gα isoforms and some cascades involve βγ signaling. The activity of 5-HT1AR usually promotes a reduction in neuronal excitability and firing, provokes a variation in cAMP and Ca2+, levels which may be linked to specific types of behavior and cognition. Furthermore, evidence indicates that 5-HT1AR induces neuritogesis and synapse formation, probably by modulation of the neuronal cytoskeleton through MAPK and PI3K-Akt signaling pathways. Advances in understanding the actions of 5-HT1AR and its association with different signaling pathways in the central nervous system will reveal their pivotal role in health and disease.

  3. Balance of excitation and inhibition determines 1/f power spectrum in neuronal networks.

    Science.gov (United States)

    Lombardi, F; Herrmann, H J; de Arcangelis, L

    2017-04-01

    The 1/f-like decay observed in the power spectrum of electro-physiological signals, along with scale-free statistics of the so-called neuronal avalanches, constitutes evidence of criticality in neuronal systems. Recent in vitro studies have shown that avalanche dynamics at criticality corresponds to some specific balance of excitation and inhibition, thus suggesting that this is a basic feature of the critical state of neuronal networks. In particular, a lack of inhibition significantly alters the temporal structure of the spontaneous avalanche activity and leads to an anomalous abundance of large avalanches. Here, we study the relationship between network inhibition and the scaling exponent β of the power spectral density (PSD) of avalanche activity in a neuronal network model inspired in Self-Organized Criticality. We find that this scaling exponent depends on the percentage of inhibitory synapses and tends to the value β = 1 for a percentage of about 30%. More specifically, β is close to 2, namely, Brownian noise, for purely excitatory networks and decreases towards values in the interval [1, 1.4] as the percentage of inhibitory synapses ranges between 20% and 30%, in agreement with experimental findings. These results indicate that the level of inhibition affects the frequency spectrum of resting brain activity and suggest the analysis of the PSD scaling behavior as a possible tool to study pathological conditions.

  4. Estradiol upregulates progesterone receptor and orphanin FQ colocalization in arcuate nucleus neurons and opioid receptor-like receptor-1 expression in proopiomelanocortin neurons that project to the medial preoptic nucleus in the female rat

    Science.gov (United States)

    Sanathara, Nayna M.; Moreas, Justine; Mahavongtrakul, Matthew; Sinchak, Kevin

    2014-01-01

    Background Ovarian steroids regulate sexual receptivity in the female rat by acting on neurons that converge on proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARH) that project to the medial preoptic nucleus (MPN). Estradiol rapidly activates these neurons to release β-endorphin that activates MPN μ-opioid receptors (MOP) to inhibit lordosis. Lordosis is facilitated by the subsequent action of progesterone that deactivates the estradiol-induced MPN MOP activation. Orphanin FQ (OFQ/N; aka nociceptin) infusions into the ARH, like progesterone, deactivate MPN MOP and facilitate lordosis in estradiol-primed rats. OFQ/N reduces the activity of ARH β-endorphin neurons through post- and presynaptic mechanisms via its cognate receptor, ORL-1. Methods We tested the hypotheses that progesterone receptors (PR) are expressed in ARH OFQ/N neurons by immunohistochemistry and ORL-1 is expressed in POMC neurons that project to the MPN by combining Fluoro-Gold injection into the MPN and double-label fluorescent in situ hybridization (FISH). We also hypothesized that estradiol increases coexpression of PR-OFQ/N and ORL-1-POMC in ARH neurons of ovariectomized rats. Results The number of PR and OFQ/N immunopositive ARH neurons was increased as was their colocalization by estradiol treatment. FISH for ORL-1 and POMC mRNA revealed a subpopulation of ARH neurons that was triple-labeled indicating these neurons project to the MPN and coexpress ORL-1 and POMC mRNA. Estradiol was shown to upregulate ORL-1 and POMC expression in MPN-projecting ARH neurons. Conclusion Estradiol upregulates the ARH OFQ/N-ORL-1 system projecting to the MPN that regulates lordosis. PMID:24821192

  5. Serotonin-mediated modulation of Na+/K+ pump current in rat hippocampal CA1 pyramidal neurons.

    Science.gov (United States)

    Zhang, Li Nan; Su, Su Wen; Guo, Fang; Guo, Hui Cai; Shi, Xiao Lu; Li, Wen Ya; Liu, Xu; Wang, Yong Li

    2012-01-19

    The aim of this study was to investigate whether serotonin (5-hydroxytryptamine, 5-HT) can modulate Na+/K+ pump in rat hippocampal CA1 pyramidal neurons. 5-HT (0.1, 1 mM) showed Na+/K+ pump current (Ip) densities of 0.40 ± 0.04, 0.34 ± 0.03 pA/pF contrast to 0.63 ± 0.04 pA/pF of the control of 0.5 mM strophanthidin (Str), demonstrating 5-HT-induced inhibition of Ip in a dose-dependent manner in hippocampal CA1 pyramidal neurons. The effect was partly attenuated by ondasetron, a 5-HT3 receptor (5-HT3R) antagonist, not by WAY100635, a 5-HT1AR antagonist, while 1-(3-Chlorophenyl) biguanide hydrochloride (m-CPBG), a 5-HT3R specific agonist, mimicked the effect of 5-HT on Ip. 5-HT inhibits neuronal Na+/K+ pump activity via 5-HT3R in rat hippocampal CA1 pyramidal neurons. This discloses novel mechanisms for the function of 5-HT in learning and memory, which may be a useful target to benefit these patients with cognitive disorder.

  6. In vitro evidence of glucose-induced toxicity in GnRH secreting neurons: high glucose concentrations influence GnRH secretion, impair cell viability, and induce apoptosis in the GT1-1 neuronal cell line.

    Science.gov (United States)

    Pal, Lubna; Chu, Hsiao-Pai; Shu, Jun; Topalli, Ilir; Santoro, Nanette; Karkanias, George

    2007-10-01

    To evaluate for direct toxic effects of high glucose concentrations on cellular physiology in GnRH secreting immortalized GT1-1 neurons. Prospective experimental design. In vitro experimental model using a cell culture system. GT1-1 cells were cultured in replicates in media with two different glucose concentrations (450 mg/dL and 100 mg/dL, respectively) for varying time intervals (24, 48, and 72 hours). Effects of glucose concentrations on GnRH secretion by the GT1-1 neurons were evaluated using a static culture model. Cell viability, cellular apoptosis, and cell cycle events in GT1-1 neurons maintained in two different glucose concentrations were assessed by flow cytometry (fluorescence-activated cell sorter) using Annexin V-PI staining. Adverse influences of high glucose concentrations on GnRH secretion and cell viability were noted in cultures maintained in high glucose concentration (450 mg/dL) culture medium for varying time intervals. A significantly higher percentage of cells maintained in high glucose concentration medium demonstrated evidence of apoptosis by a fluorescence-activated cell sorter. We provide in vitro evidence of glucose-induced cellular toxicity in GnRH secreting GT1-1 neurons. Significant alterations in GnRH secretion, reduced cell viability, and a higher percentage of apoptotic cells were observed in GT1-1 cells maintained in high (450 mg/dL) compared with low (100 mg/dL) glucose concentration culture medium.

  7. Schaffer collateral inputs to CA1 excitatory and inhibitory neurons follow different connectivity rules.

    Science.gov (United States)

    Kwon, Osung; Feng, Linqing; Druckmann, Shaul; Kim, Jinhyun

    2018-05-04

    Neural circuits, governed by a complex interplay between excitatory and inhibitory neurons, are the substrate for information processing, and the organization of synaptic connectivity in neural network is an important determinant of circuit function. Here, we analyzed the fine structure of connectivity in hippocampal CA1 excitatory and inhibitory neurons innervated by Schaffer collaterals (SCs) using mGRASP in male mice. Our previous study revealed spatially structured synaptic connectivity between CA3-CA1 pyramidal cells (PCs). Surprisingly, parvalbumin-positive interneurons (PVs) showed a significantly more random pattern spatial structure. Notably, application of Peters' Rule for synapse prediction by random overlap between axons and dendrites enhanced structured connectivity in PCs, but, by contrast, made the connectivity pattern in PVs more random. In addition, PCs in a deep sublayer of striatum pyramidale appeared more highly structured than PCs in superficial layers, and little or no sublayer specificity was found in PVs. Our results show that CA1 excitatory PCs and inhibitory PVs innervated by the same SC inputs follow different connectivity rules. The different organizations of fine scale structured connectivity in hippocampal excitatory and inhibitory neurons provide important insights into the development and functions of neural networks. SIGNIFICANCE STATEMENT Understanding how neural circuits generate behavior is one of the central goals of neuroscience. An important component of this endeavor is the mapping of fine-scale connection patterns that underlie, and help us infer, signal processing in the brain. Here, using our recently developed synapse detection technology (mGRASP and neuTube), we provide detailed profiles of synaptic connectivity in excitatory (CA1 pyramidal) and inhibitory (CA1 parvalbumin-positive) neurons innervated by the same presynaptic inputs (CA3 Schaffer collaterals). Our results reveal that these two types of CA1 neurons follow

  8. Microfluidic measurement of effects of ACF7/MACF1 gene on the mechanics of primary cortical neurons

    Science.gov (United States)

    Lee, Donghee; Ka, Minhan; Kim, Woo-Yang; Ryu, Sangjin

    2014-03-01

    Actin filaments and microtubules play important roles in determining the mechanics of cells, and ACF7/MACF1 (Actin Crosslinking Family 7/Microtubule And Actin Crosslinking Factor 1) gene seems to be closely related to connections between actin filaments and microtubules. To identify such roles of the ACF7/MACF1 gene of primary cortical neurons, we isolated neuronal cells from the cerebral cortex of the embryonic mouse brain, which is important in memory, language and perception. We exerted viscous shear flow to normal neuronal cells and ACF7/MACF1 gene knockout neuronal cells using rectangular microfluidic channels. While changing viscous shear stress on the cells, we recorded changes in the morphology of the two cell types using video microscopy. Having analyzed the deformation of the cells, we could quantitatively correlate differences in the morphological change between the both normal and ACF7/MACF1 gene knockout neuronal cells to the applied shear force, which will contribute toward identifying cell mechanical roles of the ACF7/MACF1 gene.

  9. Microglia kill amyloid-beta1-42 damaged neurons by a CD14-dependent process

    NARCIS (Netherlands)

    Bate, Clive; Veerhuis, Robert; Eikelenboom, Piet; Williams, Alun

    2004-01-01

    Activated microglia are closely associated with neuronal damage in Alzheimer's disease. In the present study, neurons exposed to low concentrations of amyloid-beta1-42, a toxic fragment of the amyloid-beta protein, were killed by microglia in a process that required cell-cell contact. Pre-treating

  10. Activity of D1/2 Receptor Expressing Neurons in the Nucleus Accumbens Regulates Running, Locomotion, and Food Intake

    Directory of Open Access Journals (Sweden)

    Xianglong eZhu

    2016-04-01

    Full Text Available While weight gain is clearly promoted by excessive energy intake and reduced expenditure, the underlying neural mechanisms of energy balance remain unclear. The NAc is one brain region that has received attention for its role in the regulation of energy balance; its D1 and D2 receptor containing neurons have distinct functions in regulating reward behavior and require further examination. The goal of the present study is to investigate how activation and inhibition of D1 and D2 neurons in the NAc influences behaviors related to energy intake and expenditure. Specific manipulation of D1 vs D2 neurons was done in both low expenditure and high expenditure (wheel running conditions to assess behavioral effects in these different states. Direct control of neural activity was achieved using a DREADD (Designer Receptors Exclusively Activated by Designer Drugs strategy. Activation of NAc D1 neurons increased food intake, wheel running and locomotor activity. In contrast, activation of D2 neurons in the NAc reduced running and locomotion while D2 neuron inhibition had opposite effects. These results highlight the importance of considering both intake and expenditure in the analysis of D1 and D2 neuronal manipulations. Moreover, the behavioral outcomes from D1 NAc neuronal manipulations depend upon the activity state of the animals (wheel running vs non-running. The data support and complement the hypothesis of specific NAc dopamine pathways facilitating energy expenditure and suggest a potential strategy for human weight control.

  11. Finding small OBDDs for incompletely specified truth tables is hard

    DEFF Research Database (Denmark)

    Miltersen, Peter Bro; Kristensen, Jesper Torp

    2006-01-01

    We present an efficient reduction mapping undirected graphs G with n = 2^k vertices for integers k to tables of partially specified Boolean functions g: {0,1}^(4k+1) -> {0,1,*} so that for any integer m, G has a vertex colouring using m colours if and only if g has a consistent ordered binary dec...... decision diagram with at most (2m + 2)n^2 + 4n decision nodes. From this it follows that the problem of finding a minimum-sized consistent OBDD for an incompletely specified truth table is NP-hard and also hard to approximate....

  12. Stochastic optimal control of single neuron spike trains

    DEFF Research Database (Denmark)

    Iolov, Alexandre; Ditlevsen, Susanne; Longtin, Andrë

    2014-01-01

    stimulation of a neuron to achieve a target spike train under the physiological constraint to not damage tissue. Approach. We pose a stochastic optimal control problem to precisely specify the spike times in a leaky integrate-and-fire (LIF) model of a neuron with noise assumed to be of intrinsic or synaptic...... origin. In particular, we allow for the noise to be of arbitrary intensity. The optimal control problem is solved using dynamic programming when the controller has access to the voltage (closed-loop control), and using a maximum principle for the transition density when the controller only has access...... to the spike times (open-loop control). Main results. We have developed a stochastic optimal control algorithm to obtain precise spike times. It is applicable in both the supra-threshold and sub-threshold regimes, under open-loop and closed-loop conditions and with an arbitrary noise intensity; the accuracy...

  13. Taste bud cells and nerves

    OpenAIRE

    武田,正子/内田,暢彦/鈴木,裕子; タケダ,マサコ/ウチダ,ノブヒコ/スズキ,ユウコ; TAKEDA,Masako/UCHIDA,Nobuhiko/SUZUKI,Yuko

    2002-01-01

    Sectioning of glossopharyngeal nerves which innervate the taste buds in the circumvallate papillae caused apoptosis of taste buds, the numbers decreasing and the taste buds disappearing after 11 days. This indicates that gustatory nerves may release a trophic substance that induces and maintains taste buds. Taste bud cells contain neurotrophins, NCAM, NSE, PGP9.5, and NeuroD which are specific markers of neurons. The BDNF and GDNF of neurotrophins, and Trk B and GFRαl of their receptors were ...

  14. DELETION OR INHIBITION OF THE OXYGEN SENSOR PHD1 PROTECTS AGAINST ISCHEMIC STROKE VIA REPROGRAMMING OF NEURONAL METABOLISM

    Science.gov (United States)

    Quaegebeur, Annelies; Segura, Inmaculada; Schmieder, Roberta; Verdegem, Dries; Decimo, Ilaria; Bifari, Francesco; Dresselaers, Tom; Eelen, Guy; Ghosh, Debapriva; Schoors, Sandra; Janaki Raman, Sudha Rani; Cruys, Bert; Govaerts, Kristof; De Legher, Carla; Bouché, Ann; Schoonjans, Luc; Ramer, Matt S.; Hung, Gene; Bossaert, Goele; Cleveland, Don W.; Himmelreich, Uwe; Voets, Thomas; Lemmens, Robin; Bennett, C. Frank; Robberecht, Wim; De Bock, Katrien; Dewerchin, Mieke; Fendt, Sarah-Maria; Ghesquière, Bart; Carmeliet, Peter

    2016-01-01

    Summary The oxygen-sensing prolyl hydroxylase domain proteins (PHDs) regulate cellular metabolism, but their role in neuronal metabolism during stroke is unknown. Here we report that PHD1 deficiency provides neuroprotection in a murine model of permanent brain ischemia. This was not due to an increased collateral vessel network, nor to enhanced neurotrophin expression. Instead, PHD1−/− neurons were protected against oxygen-nutrient deprivation by reprogramming glucose metabolism. Indeed, PHD1−/− neurons enhanced glucose flux through the oxidative pentose phosphate pathway by diverting glucose from glycolysis. As a result, PHD1−/− neurons increased their redox buffering capacity to scavenge oxygen radicals in ischemia. Intracerebroventricular injection of PHD1-antisense oligonucleotides reduced the cerebral infarct size and neurological deficits following stroke. These data identify PHD1 as a novel regulator of neuronal metabolism and a potential therapeutic target in ischemic stroke. PMID:26774962

  15. Tuberal hypothalamic neurons secreting the satiety molecule Nesfatin-1 are critically involved in paradoxical (REM sleep homeostasis.

    Directory of Open Access Journals (Sweden)

    Sonia Jego

    Full Text Available The recently discovered Nesfatin-1 plays a role in appetite regulation as a satiety factor through hypothalamic leptin-independent mechanisms. Nesfatin-1 is co-expressed with Melanin-Concentrating Hormone (MCH in neurons from the tuberal hypothalamic area (THA which are recruited during sleep states, especially paradoxical sleep (PS. To help decipher the contribution of this contingent of THA neurons to sleep regulatory mechanisms, we thus investigated in rats whether the co-factor Nesfatin-1 is also endowed with sleep-modulating properties. Here, we found that the disruption of the brain Nesfatin-1 signaling achieved by icv administration of Nesfatin-1 antiserum or antisense against the nucleobindin2 (NUCB2 prohormone suppressed PS with little, if any alteration of slow wave sleep (SWS. Further, the infusion of Nesfatin-1 antiserum after a selective PS deprivation, designed for elevating PS needs, severely prevented the ensuing expected PS recovery. Strengthening these pharmacological data, we finally demonstrated by using c-Fos as an index of neuronal activation that the recruitment of Nesfatin-1-immunoreactive neurons within THA is positively correlated to PS but not to SWS amounts experienced by rats prior to sacrifice. In conclusion, this work supports a functional contribution of the Nesfatin-1 signaling, operated by THA neurons, to PS regulatory mechanisms. We propose that these neurons, likely releasing MCH as a synergistic factor, constitute an appropriate lever by which the hypothalamus may integrate endogenous signals to adapt the ultradian rhythm and maintenance of PS in a manner dictated by homeostatic needs. This could be done through the inhibition of downstream targets comprised primarily of the local hypothalamic wake-active orexin- and histamine-containing neurons.

  16. Involvement of cyclin D1/CDK4 and pRb mediated by PI3K/AKT pathway activation in Pb2+-induced neuronal death in cultured hippocampal neurons

    International Nuclear Information System (INIS)

    Li Chenchen; Xing Tairan; Tang Mingliang; Yong Wu; Yan Dan; Deng Hongmin; Wang Huili; Wang Ming; Chen Jutao; Ruan Diyun

    2008-01-01

    Lead (Pb) is widely recognized as a neurotoxicant. One of the suggested mechanisms of lead neurotoxicity is apoptotic cell death. And the mechanism by which Pb 2+ causes neuronal death is not well understood. The present study sought to examine the obligate nature of cyclin D1/cyclin-dependent kinase 4 (CDK4), phosphorylation of its substrate retinoblastoma protein (pRb) and its select upstream signal phosphoinositide 3-kinase (PI3K)/AKT pathway in the death of primary cultured rat hippocampal neurons evoked by Pb 2+ . Our data showed that lead treatment of primary hippocampal cultures results in dose-dependent cell death. Inhibition of CDK4 prevented Pb 2+ -induced neuronal death significantly but was incomplete. In addition, we demonstrated that the levels of cyclin D1 and pRb/p107 were increased during Pb 2+ treatment. These elevated expression persisted up to 48 h, returning to control levels after 72 h. We also presented pharmacological and morphological evidences that cyclin D1/CDK4 and pRb/p107 were required for such kind of neuronal death. Addition of the PI3K inhibitor LY294002 (30 μM) or wortmannin (100 nM) significantly rescued the cultured hippocampal neurons from death caused by Pb 2+ . And that Pb 2+ -elicited phospho-AKT (Ser473) participated in the induction of cyclin D1 and partial pRb/p107 expression. These results provide evidences that cell cycle elements play a required role in the death of neurons evoked by Pb 2+ and suggest that certain signaling elements upstream of cyclin D1/CDK4 are modified and/or required for this form of neuronal death

  17. Transduced PEP-1-PON1 proteins regulate microglial activation and dopaminergic neuronal death in a Parkinson's disease model.

    Science.gov (United States)

    Kim, Mi Jin; Park, Meeyoung; Kim, Dae Won; Shin, Min Jea; Son, Ora; Jo, Hyo Sang; Yeo, Hyeon Ji; Cho, Su Bin; Park, Jung Hwan; Lee, Chi Hern; Kim, Duk-Soo; Kwon, Oh-Shin; Kim, Joon; Han, Kyu Hyung; Park, Jinseu; Eum, Won Sik; Choi, Soo Young

    2015-09-01

    Parkinson's disease (PD) is an oxidative stress-mediated neurodegenerative disorder caused by selective dopaminergic neuronal death in the midbrain substantia nigra. Paraoxonase 1 (PON1) is a potent inhibitor of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) against oxidation by destroying biologically active phospholipids with potential protective effects against oxidative stress-induced inflammatory disorders. In a previous study, we constructed protein transduction domain (PTD) fusion PEP-1-PON1 protein to transduce PON1 into cells and tissue. In this study, we examined the role of transduced PEP-1-PON1 protein in repressing oxidative stress-mediated inflammatory response in microglial BV2 cells after exposure to lipopolysaccharide (LPS). Moreover, we identified the functions of transduced PEP-1-PON1 proteins which include, mitigating mitochondrial damage, decreasing reactive oxidative species (ROS) production, matrix metalloproteinase-9 (MMP-9) expression and protecting against 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity in SH-SY5Y cells. Furthermore, transduced PEP-1-PON1 protein reduced MMP-9 expression and protected against dopaminergic neuronal cell death in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice model. Taken together, these results suggest a promising therapeutic application of PEP-1-PON1 proteins against PD and other inflammation and oxidative stress-related neuronal diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. eGFP expression under the Uchl1 promoter labels corticospinal motor neurons and a subpopulation of degeneration resistant spinal motor neurons in ALS mouse models

    Science.gov (United States)

    Yasvoina, Marina V.

    Current understanding of basic cellular and molecular mechanisms for motor neuron vulnerability during motor neuron disease initiation and progression is incomplete. The complex cytoarchitecture and cellular heterogeneity of the cortex and spinal cord greatly impedes our ability to visualize, isolate, and study specific neuron populations in both healthy and diseased states. We generated a novel reporter line, the Uchl1-eGFP mouse, in which cortical and spinal components of motor neuron circuitry are genetically labeled with eGFP under the Uchl1 promoter. A series of cellular and anatomical analyses combined with retrograde labeling, molecular marker expression, and electrophysiology were employed to determine identity of eGFP expressing cells in the motor cortex and the spinal cord of novel Uchl1-eGFP reporter mice. We conclude that eGFP is expressed in corticospinal motor neurons (CSMN) in the motor cortex and a subset of S-type alpha and gamma spinal motor neurons (SMN) in the spinal cord. hSOD1G93A and Alsin-/- mice, mouse models for amyotrophic lateral sclerosis (ALS), were bred to Uchl1-eGFP reporter mouse line to investigate the pathophysiology and underlying mechanisms of CSMN degeneration in vivo. Evidence suggests early and progressive degeneration of CSMN and SMN in the hSOD1G93A transgenic mice. We show an early increase of autophagosome formation in the apical dendrites of vulnerable CSMN in hSOD1G93A-UeGFP mice, which is localized to the apical dendrites. In addition, labeling S-type alpha and gamma SMN in the hSOD1G93A-UeGFP mice provide a unique opportunity to study basis of their resistance to degeneration. Mice lacking alsin show moderate clinical phenotype and mild CSMN axon degeneration in the spinal cord, which suggests vulnerability of CSMN. Therefore, we investigated the CSMN cellular and axon defects in aged Alsin-/- mice bred to Uchl1-eGFP reporter mouse line. We show that while CSMN are preserved and lack signs of degeneration, CSMN axons

  19. The LIM and POU homeobox genes ttx-3 and unc-86 act as terminal selectors in distinct cholinergic and serotonergic neuron types.

    Science.gov (United States)

    Zhang, Feifan; Bhattacharya, Abhishek; Nelson, Jessica C; Abe, Namiko; Gordon, Patricia; Lloret-Fernandez, Carla; Maicas, Miren; Flames, Nuria; Mann, Richard S; Colón-Ramos, Daniel A; Hobert, Oliver

    2014-01-01

    Transcription factors that drive neuron type-specific terminal differentiation programs in the developing nervous system are often expressed in several distinct neuronal cell types, but to what extent they have similar or distinct activities in individual neuronal cell types is generally not well explored. We investigate this problem using, as a starting point, the C. elegans LIM homeodomain transcription factor ttx-3, which acts as a terminal selector to drive the terminal differentiation program of the cholinergic AIY interneuron class. Using a panel of different terminal differentiation markers, including neurotransmitter synthesizing enzymes, neurotransmitter receptors and neuropeptides, we show that ttx-3 also controls the terminal differentiation program of two additional, distinct neuron types, namely the cholinergic AIA interneurons and the serotonergic NSM neurons. We show that the type of differentiation program that is controlled by ttx-3 in different neuron types is specified by a distinct set of collaborating transcription factors. One of the collaborating transcription factors is the POU homeobox gene unc-86, which collaborates with ttx-3 to determine the identity of the serotonergic NSM neurons. unc-86 in turn operates independently of ttx-3 in the anterior ganglion where it collaborates with the ARID-type transcription factor cfi-1 to determine the cholinergic identity of the IL2 sensory and URA motor neurons. In conclusion, transcription factors operate as terminal selectors in distinct combinations in different neuron types, defining neuron type-specific identity features.

  20. NDRG2 promoted secreted miR-375 in microvesicles shed from M1 microglia, which induced neuron damage.

    Science.gov (United States)

    Tang, Li-li; Wu, Yuan-bo; Fang, Chuan-qin; Qu, Ping; Gao, Zong-liang

    2016-01-15

    Microglia microvesicles (MVs) has shown to have significant biological functions under normal conditions. A diversity of miRNAs is involved in neuronal development, survival, function, and plasticity, but the exact functional role of NDRG2 and secreted miR-375 in MVs in neuron damage is poorly understood. We investigated the effect of NDRG2 and secreted miR-375 in MVs shed from M1 microglia on neuron damage. Expression of Nos2, Arg-1, miR-375, syntaxin-1A, NDRG2 and Pdk 1 were evaluated using RT-PCR or western blotting. Cell viability of N2A neuron was quantified by a MTT assay. Microglia can be polarized into different functional phenotypes. Expression of NDRG2 and Nos2 were significantly increased by LPS treatment on N9 cells, whereas treatment with IL-4 dramatically suppressed the expression of NDRG2 and remarkably elevated expression of Arg-1. Besides, MVs shed from LPS-treated N9 microglia significantly inhibited cell viability of N2A neurons and expression of syntaxin-1A, and NDRG2 interference reversed the up-regulated miR-375 in LPS-treated N9 microglia and MVs shed from LPS-treated N9 cells. Furthermore, NDRG2 could modulate miR-375 expression in N9 microglia and MVs. And miR-375 inhibitor remarkably elevated Pdk1 expression in N2A neurons. Finally, miR-375 inhibitor could reverse suppression effect of NDRG2 overexpression on cell viability of N2A neurons and expression of syntaxin-1A. Our results demonstrated that NDRG2 promoted secreted miR-375 in microvesicles shed from M1 microglia, which induced neuron damage. The suppression of NDRG2 and secreted miR-375 in MVs shed from M1 microglia may be potential targets for alleviation of neuron damage. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Stress-induced localization of HSPA6 (HSP70B') and HSPA1A (HSP70-1) proteins to centrioles in human neuronal cells.

    Science.gov (United States)

    Khalouei, Sam; Chow, Ari M; Brown, Ian R

    2014-05-01

    The localization of yellow fluorescent protein (YFP)-tagged HSP70 proteins was employed to identify stress-sensitive sites in human neurons following temperature elevation. Stable lines of human SH-SY5Y neuronal cells were established that expressed YFP-tagged protein products of the human inducible HSP70 genes HSPA6 (HSP70B') and HSPA1A (HSP70-1). Following a brief period of thermal stress, YFP-tagged HSPA6 and HSPA1A rapidly appeared at centrioles in the cytoplasm of human neuronal cells, with HSPA6 demonstrating a more prolonged signal compared to HSPA1A. Each centriole is composed of a distal end and a proximal end, the latter linking the centriole doublet. The YFP-tagged HSP70 proteins targeted the proximal end of centrioles (identified by γ-tubulin marker) rather than the distal end (centrin marker). Centrioles play key roles in cellular polarity and migration during neuronal differentiation. The proximal end of the centriole, which is involved in centriole stabilization, may be stress-sensitive in post-mitotic, differentiating human neurons.

  2. Neuronal Kmt2a/Mll1 histone methyltransferase is essential for prefrontal synaptic plasticity and working memory.

    Science.gov (United States)

    Jakovcevski, Mira; Ruan, Hongyu; Shen, Erica Y; Dincer, Aslihan; Javidfar, Behnam; Ma, Qi; Peter, Cyril J; Cheung, Iris; Mitchell, Amanda C; Jiang, Yan; Lin, Cong L; Pothula, Venu; Stewart, A Francis; Ernst, Patricia; Yao, Wei-Dong; Akbarian, Schahram

    2015-04-01

    Neuronal histone H3-lysine 4 methylation landscapes are defined by sharp peaks at gene promoters and other cis-regulatory sequences, but molecular and cellular phenotypes after neuron-specific deletion of H3K4 methyl-regulators remain largely unexplored. We report that neuronal ablation of the H3K4-specific methyltransferase, Kmt2a/Mixed-lineage leukemia 1 (Mll1), in mouse postnatal forebrain and adult prefrontal cortex (PFC) is associated with increased anxiety and robust cognitive deficits without locomotor dysfunction. In contrast, only mild behavioral phenotypes were observed after ablation of the Mll1 ortholog Kmt2b/Mll2 in PFC. Impaired working memory after Kmt2a/Mll1 ablation in PFC neurons was associated with loss of training-induced transient waves of Arc immediate early gene expression critical for synaptic plasticity. Medial prefrontal layer V pyramidal neurons, a major output relay of the cortex, demonstrated severely impaired synaptic facilitation and temporal summation, two forms of short-term plasticity essential for working memory. Chromatin immunoprecipitation followed by deep sequencing in Mll1-deficient cortical neurons revealed downregulated expression and loss of the transcriptional mark, trimethyl-H3K4, at <50 loci, including the homeodomain transcription factor Meis2. Small RNA-mediated Meis2 knockdown in PFC was associated with working memory defects similar to those elicited by Mll1 deletion. Therefore, mature prefrontal neurons critically depend on maintenance of Mll1-regulated H3K4 methylation at a subset of genes with an essential role in cognition and emotion. Copyright © 2015 the authors 0270-6474/15/355097-12$15.00/0.

  3. Detection of phasic dopamine by D1 and D2 striatal medium spiny neurons.

    Science.gov (United States)

    Yapo, Cedric; Nair, Anu G; Clement, Lorna; Castro, Liliana R; Hellgren Kotaleski, Jeanette; Vincent, Pierre

    2017-12-15

    Brief dopamine events are critical actors of reward-mediated learning in the striatum; the intracellular cAMP-protein kinase A (PKA) response of striatal medium spiny neurons to such events was studied dynamically using a combination of biosensor imaging in mouse brain slices and in silico simulations. Both D1 and D2 medium spiny neurons can sense brief dopamine transients in the sub-micromolar range. While dopamine transients profoundly change cAMP levels in both types of medium spiny neurons, the PKA-dependent phosphorylation level remains unaffected in D2 neurons. At the level of PKA-dependent phosphorylation, D2 unresponsiveness depends on protein phosphatase-1 (PP1) inhibition by DARPP-32. Simulations suggest that D2 medium spiny neurons could detect transient dips in dopamine level. The phasic release of dopamine in the striatum determines various aspects of reward and action selection, but the dynamics of the dopamine effect on intracellular signalling remains poorly understood. We used genetically encoded FRET biosensors in striatal brain slices to quantify the effect of transient dopamine on cAMP or PKA-dependent phosphorylation levels, and computational modelling to further explore the dynamics of this signalling pathway. Medium-sized spiny neurons (MSNs), which express either D 1 or D 2 dopamine receptors, responded to dopamine by an increase or a decrease in cAMP, respectively. Transient dopamine showed similar sub-micromolar efficacies on cAMP in both D1 and D2 MSNs, thus challenging the commonly accepted notion that dopamine efficacy is much higher on D 2 than on D 1 receptors. However, in D2 MSNs, the large decrease in cAMP level triggered by transient dopamine did not translate to a decrease in PKA-dependent phosphorylation level, owing to the efficient inhibition of protein phosphatase 1 by DARPP-32. Simulations further suggested that D2 MSNs can also operate in a 'tone-sensing' mode, allowing them to detect transient dips in basal dopamine

  4. PRRT2 controls neuronal excitability by negatively modulating Na+ channel 1.2/1.6 activity.

    Science.gov (United States)

    Fruscione, Floriana; Valente, Pierluigi; Sterlini, Bruno; Romei, Alessandra; Baldassari, Simona; Fadda, Manuela; Prestigio, Cosimo; Giansante, Giorgia; Sartorelli, Jacopo; Rossi, Pia; Rubio, Alicia; Gambardella, Antonio; Nieus, Thierry; Broccoli, Vania; Fassio, Anna; Baldelli, Pietro; Corradi, Anna; Zara, Federico; Benfenati, Fabio

    2018-04-01

    See Lerche (doi:10.1093/brain/awy073) for a scientific commentary on this article.Proline-rich transmembrane protein 2 (PRRT2) is the causative gene for a heterogeneous group of familial paroxysmal neurological disorders that include seizures with onset in the first year of life (benign familial infantile seizures), paroxysmal kinesigenic dyskinesia or a combination of both. Most of the PRRT2 mutations are loss-of-function leading to haploinsufficiency and 80% of the patients carry the same frameshift mutation (c.649dupC; p.Arg217Profs*8), which leads to a premature stop codon. To model the disease and dissect the physiological role of PRRT2, we studied the phenotype of neurons differentiated from induced pluripotent stem cells from previously described heterozygous and homozygous siblings carrying the c.649dupC mutation. Single-cell patch-clamp experiments on induced pluripotent stem cell-derived neurons from homozygous patients showed increased Na+ currents that were fully rescued by expression of wild-type PRRT2. Closely similar electrophysiological features were observed in primary neurons obtained from the recently characterized PRRT2 knockout mouse. This phenotype was associated with an increased length of the axon initial segment and with markedly augmented spontaneous and evoked firing and bursting activities evaluated, at the network level, by multi-electrode array electrophysiology. Using HEK-293 cells stably expressing Nav channel subtypes, we demonstrated that the expression of PRRT2 decreases the membrane exposure and Na+ current of Nav1.2/Nav1.6, but not Nav1.1, channels. Moreover, PRRT2 directly interacted with Nav1.2/Nav1.6 channels and induced a negative shift in the voltage-dependence of inactivation and a slow-down in the recovery from inactivation. In addition, by co-immunoprecipitation assays, we showed that the PRRT2-Nav interaction also occurs in brain tissue. The study demonstrates that the lack of PRRT2 leads to a hyperactivity of voltage

  5. PRRT2 controls neuronal excitability by negatively modulating Na+ channel 1.2/1.6 activity

    Science.gov (United States)

    Fruscione, Floriana; Valente, Pierluigi; Sterlini, Bruno; Romei, Alessandra; Baldassari, Simona; Fadda, Manuela; Prestigio, Cosimo; Giansante, Giorgia; Sartorelli, Jacopo; Rossi, Pia; Rubio, Alicia; Gambardella, Antonio; Nieus, Thierry; Broccoli, Vania; Fassio, Anna; Baldelli, Pietro; Corradi, Anna; Zara, Federico

    2018-01-01

    Abstract See Lerche (doi:10.1093/brain/awy073) for a scientific commentary on this article. Proline-rich transmembrane protein 2 (PRRT2) is the causative gene for a heterogeneous group of familial paroxysmal neurological disorders that include seizures with onset in the first year of life (benign familial infantile seizures), paroxysmal kinesigenic dyskinesia or a combination of both. Most of the PRRT2 mutations are loss-of-function leading to haploinsufficiency and 80% of the patients carry the same frameshift mutation (c.649dupC; p.Arg217Profs*8), which leads to a premature stop codon. To model the disease and dissect the physiological role of PRRT2, we studied the phenotype of neurons differentiated from induced pluripotent stem cells from previously described heterozygous and homozygous siblings carrying the c.649dupC mutation. Single-cell patch-clamp experiments on induced pluripotent stem cell-derived neurons from homozygous patients showed increased Na+ currents that were fully rescued by expression of wild-type PRRT2. Closely similar electrophysiological features were observed in primary neurons obtained from the recently characterized PRRT2 knockout mouse. This phenotype was associated with an increased length of the axon initial segment and with markedly augmented spontaneous and evoked firing and bursting activities evaluated, at the network level, by multi-electrode array electrophysiology. Using HEK-293 cells stably expressing Nav channel subtypes, we demonstrated that the expression of PRRT2 decreases the membrane exposure and Na+ current of Nav1.2/Nav1.6, but not Nav1.1, channels. Moreover, PRRT2 directly interacted with Nav1.2/Nav1.6 channels and induced a negative shift in the voltage-dependence of inactivation and a slow-down in the recovery from inactivation. In addition, by co-immunoprecipitation assays, we showed that the PRRT2-Nav interaction also occurs in brain tissue. The study demonstrates that the lack of PRRT2 leads to a hyperactivity of

  6. PGC-1α expression in murine AgRP neurons regulates food intake and energy balance

    Directory of Open Access Journals (Sweden)

    Jonathan F. Gill

    2016-07-01

    Full Text Available Objective: Food intake and whole-body energy homeostasis are controlled by agouti-related protein (AgRP and pro-opiomelanocortin (POMC neurons located in the arcuate nucleus of the hypothalamus. Key energy sensors, such as the AMP-activated protein kinase (AMPK or sirtuin 1 (SIRT1, are essential in AgRP and POMC cells to ensure proper energy balance. In peripheral tissues, the transcriptional coactivator PGC-1α closely associates with these sensors to regulate cellular metabolism. The role of PGC-1α in the ARC nucleus, however, remains unknown. Methods: Using AgRP and POMC neurons specific knockout (KO mouse models we studied the consequences of PGC-1α deletion on metabolic parameters during fed and fasted states and on ghrelin and leptin responses. We also took advantage of an immortalized AgRP cell line to assess the impact of PGC-1α modulation on fasting induced AgRP expression. Results: PGC-1α is dispensable for POMC functions in both fed and fasted states. In stark contrast, mice carrying a specific deletion of PGC-1α in AgRP neurons display increased adiposity concomitant with significantly lower body temperature and RER values during nighttime. In addition, the absence of PGC-1α in AgRP neurons reduces food intake in the fed and fasted states and alters the response to leptin. Finally, both in vivo and in an immortalized AgRP cell line, PGC-1α modulates AgRP expression induction upon fasting. Conclusions: Collectively, our results highlight a role for PGC-1α in the regulation of AgRP neuronal functions in the control of food intake and peripheral metabolism. Author Video: Author Video Watch what authors say about their articles Keywords: PGC-1α, Agouti-related protein, Metabolism, Energy homeostasis, Pro-opiomelanocortin, Transcriptional regulation

  7. Amyloid-β triggers the release of neuronal hexokinase 1 from mitochondria.

    Directory of Open Access Journals (Sweden)

    Leonardo M Saraiva

    2010-12-01

    Full Text Available Brain accumulation of the amyloid-β peptide (Aβ and oxidative stress underlie neuronal dysfunction and memory loss in Alzheimer's disease (AD. Hexokinase (HK, a key glycolytic enzyme, plays important pro-survival roles, reducing mitochondrial reactive oxygen species (ROS generation and preventing apoptosis in neurons and other cell types. Brain isozyme HKI is mainly associated with mitochondria and HK release from mitochondria causes a significant decrease in enzyme activity and triggers oxidative damage. We here investigated the relationship between Aβ-induced oxidative stress and HK activity. We found that Aβ triggered HKI detachment from mitochondria decreasing HKI activity in cortical neurons. Aβ oligomers further impair energy metabolism by decreasing neuronal ATP levels. Aβ-induced HKI cellular redistribution was accompanied by excessive ROS generation and neuronal death. 2-deoxyglucose blocked Aβ-induced oxidative stress and neuronal death. Results suggest that Aβ-induced cellular redistribution and inactivation of neuronal HKI play important roles in oxidative stress and neurodegeneration in AD.

  8. SIRT1-mediated deacetylation of PGC1α attributes to the protection of curcumin against glutamate excitotoxicity in cortical neurons

    International Nuclear Information System (INIS)

    Jia, Ning; Sun, Qinru; Su, Qian; Chen, Guomin

    2016-01-01

    It is widely accepted that accumulation of extracellular glutamate mediates neuronal injuries in a number of neurological disorders via binding glutamate receptors. However, usage of the glutamate receptor antagonists aimed to prevent glutamate excitotoxicity is still controversial. As a polyphenol natural product, curcumin, has been implied multiple bioactivities. In this study, we explored whether the silent information regulator 1 (SIRT1)-peroxisome proliferator-activated receptor-coactivator 1α (PGC1α) pathway participated in the protection of curcumin against glutamate excitotoxicity. The cultured primary cortical neurons were treated with glutamate to set up a neuronal excitotoxicity model. The MTT and TUNEL methods were employed to measure cell viability and apoptosis, respectively. The mitochondrial function, the expression levels of SIRT1, PGC1α and acetylated PGC1α (ac-PGC1α) were measured to explore the mechanism of curcumin against glutamate excitotoxicity. The results showed that glutamate significantly induced cell death and apoptosis, which was blocked by pretreatment with curcumin. Meanwhile, curcumin preserved mitochondrial function, increased the expression level of SIRT1 and reduced the level of ac-PGC1α in the presence of glutamate. These results suggest that SIRT1-mediated deacetylation of PGC1α attributes to the neuroprotection of curcumin against glutamate excitotoxicity. - Highlights: • Curcumin attenuates glutamate induced cell death and apoptosis in cultured neurons. • Curcumin preserves mitochondrial function in the presence of glutamate. • Curcumin enhanced the expression of SIRT1 in the glutamate rich environment. • SIRT1-mediated deacetylation of PGC1α attributes to the neuroprotection of curcumin.

  9. The morphological and chemical characteristics of striatal neurons immunoreactive for the alpha1-subunit of the GABA(A) receptor in the rat.

    Science.gov (United States)

    Waldvogel, H J; Kubota, Y; Trevallyan, S C; Kawaguchi, Y; Fritschy, J M; Mohler, H; Faull, R L

    1997-10-01

    The distribution, morphology and chemical characteristics of neurons immunoreactive for the alpha1-subunit of the GABA(A) receptor in the striatum of the basal ganglia in the rat brain were investigated at the light, confocal and electron microscope levels using single, double and triple immunohistochemical labelling techniques. The results showed that alpha1-subunit immunoreactive neurons were sparsely distributed throughout the rat striatum. Double and triple labelling results showed that all the alpha1-subunit-immunoreactive neurons were positive for glutamate decarboxylase and immunoreactive for the beta2,3 and gamma2 subunits of the GABA(A) receptor. Three types of alpha1-subunit-immunoreactive neurons were identified in the striatum on the basis of cellular morphology and chemical characteristics. The most numerous alpha1-subunit-immunoreactive neurons were medium-sized, aspiny neurons with a widely branching dendritic tree. They were parvalbumin-negative and were located mainly in the dorsolateral regions of the striatum. Electron microscopy showed that these neurons had an indented nuclear membrane, typical of striatal interneurons, and were surrounded by small numbers of axon terminals which established alpha1-subunit-immunoreactive synaptic contacts with the soma and dendrites. These cells were classified as type 1 alpha1-subunit-immunoreactive neurons and comprised 75% of the total population of alpha1-subunit-immunoreactive neurons in the striatum. The remaining alpha1-subunit-immunoreactive neurons comprised of a heterogeneous population of large-sized neurons localized in the ventral and medial regions of the striatum. The most numerous large-sized cells were parvalbumin-negative, had two to three relatively short branching dendrites and were designated type 2 alpha1-subunit-immunoreactive neurons. Electron microscopy showed that the type 2 neurons were characterized by a highly convoluted nuclear membrane and were sparsely covered with small axon

  10. Conditional Deletion of PDK1 in the Forebrain Causes Neuron Loss and Increased Apoptosis during Cortical Development

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    Congyu Xu

    2017-10-01

    Full Text Available Decreased expression but increased activity of PDK1 has been observed in neurodegenerative disease. To study in vivo function of PDK1 in neuron survival during cortical development, we generate forebrain-specific PDK1 conditional knockout (cKO mice. We demonstrate that PDK1 cKO mice display striking neuron loss and increased apoptosis. We report that PDK1 cKO mice exhibit deficits on several behavioral tasks. Moreover, PDK1 cKO mice show decreased activities for Akt and mTOR. These results highlight an essential role of endogenous PDK1 in the maintenance of neuronal survival during cortical development.

  11. Pancreatic Transdifferentiation and Glucose-Regulated Production of Human Insulin in the H4IIE Rat Liver Cell Line

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    Binhai Ren

    2016-04-01

    Full Text Available Due to the limitations of current treatment regimes, gene therapy is a promising strategy being explored to correct blood glucose concentrations in diabetic patients. In the current study, we used a retroviral vector to deliver either the human insulin gene alone, the rat NeuroD1 gene alone, or the human insulin gene and rat NeuroD1 genes together, to the rat liver cell line, H4IIE, to determine if storage of insulin and pancreatic transdifferentiation occurred. Stable clones were selected and expanded into cell lines: H4IIEins (insulin gene alone, H4IIE/ND (NeuroD1 gene alone, and H4IIEins/ND (insulin and NeuroD1 genes. The H4IIEins cells did not store insulin; however, H4IIE/ND and H4IIEins/ND cells stored 65.5 ± 5.6 and 1475.4 ± 171.8 pmol/insulin/5 × 106 cells, respectively. Additionally, several β cell transcription factors and pancreatic hormones were expressed in both H4IIE/ND and H4IIEins/ND cells. Electron microscopy revealed insulin storage vesicles in the H4IIE/ND and H4IIEins/ND cell lines. Regulated secretion of insulin to glucose (0–20 mmol/L was seen in the H4IIEins/ND cell line. The H4IIEins/ND cells were transplanted into diabetic immunoincompetent mice, resulting in normalization of blood glucose. This data shows that the expression of NeuroD1 and insulin in liver cells may be a useful strategy for inducing islet neogenesis and reversing diabetes.

  12. Direct effects of HIV-1 Tat on excitability and survival of primary dorsal root ganglion neurons: possible contribution to HIV-1-associated pain.

    Directory of Open Access Journals (Sweden)

    Xianxun Chi

    Full Text Available The vast majority of people living with human immunodeficiency virus type 1 (HIV-1 have pain syndrome, which has a significant impact on their quality of life. The underlying causes of HIV-1-associated pain are not likely attributable to direct viral infection of the nervous system due to the lack of evidence of neuronal infection by HIV-1. However, HIV-1 proteins are possibly involved as they have been implicated in neuronal damage and death. The current study assesses the direct effects of HIV-1 Tat, one of potent neurotoxic viral proteins released from HIV-1-infected cells, on the excitability and survival of rat primary dorsal root ganglion (DRG neurons. We demonstrated that HIV-1 Tat triggered rapid and sustained enhancement of the excitability of small-diameter rat primary DRG neurons, which was accompanied by marked reductions in the rheobase and resting membrane potential (RMP, and an increase in the resistance at threshold (R(Th. Such Tat-induced DRG hyperexcitability may be a consequence of the inhibition of cyclin-dependent kinase 5 (Cdk5 activity. Tat rapidly inhibited Cdk5 kinase activity and mRNA production, and roscovitine, a well-known Cdk5 inhibitor, induced a very similar pattern of DRG hyperexcitability. Indeed, pre-application of Tat prevented roscovitine from having additional effects on the RMP and action potentials (APs of DRGs. However, Tat-mediated actions on the rheobase and R(Th were accelerated by roscovitine. These results suggest that Tat-mediated changes in DRG excitability are partly facilitated by Cdk5 inhibition. In addition, Cdk5 is most abundant in DRG neurons and participates in the regulation of pain signaling. We also demonstrated that HIV-1 Tat markedly induced apoptosis of primary DRG neurons after exposure for longer than 48 h. Together, this work indicates that HIV-1 proteins are capable of producing pain signaling through direct actions on excitability and survival of sensory neurons.

  13. Analyzing and Specifying Reusable Security Requirements

    Science.gov (United States)

    2003-09-01

    avionics applications and ecommerce applications need to specify levels of identification, authentication, authorization, integrity, privacy , etc. At...sections specifying functional requirements. Thus, the functional requirements for an embedded avionics application and an ecommerce website may have... Privacy (a.k.a., confidentiality), which is the degree to which sensitive data and communications are kept private from unauthorized individuals and

  14. Mitogen-activated protein kinase phosphatase (MKP)-1 as a neuroprotective agent: promotion of the morphological development of midbrain dopaminergic neurons.

    Science.gov (United States)

    Collins, Louise M; O'Keeffe, Gerard W; Long-Smith, Caitriona M; Wyatt, Sean L; Sullivan, Aideen M; Toulouse, André; Nolan, Yvonne M

    2013-06-01

    A greater understanding of the mechanisms that promote the survival and growth of dopaminergic neurons is essential for the advancement of cell replacement therapies for Parkinson's disease (PD). Evidence supports a role for the mitogen-activated protein kinase p38 in the demise of dopaminergic neurons, while mitogen-activated protein kinase phosphatase-1 (MKP-1), which negatively regulates p38 activity, has not yet been investigated in this context. Here, we show that MKP-1 is expressed in dopaminergic neurons cultured from E14 rat ventral mesencephalon (VM). When dopaminergic neurons were transfected to overexpress MKP-1, they displayed a more complex morphology than their control counterparts in vitro. Specifically, MKP-1-transfection induced significant increases in neurite length and branching with a maximum increase observed in primary branches. We demonstrate that inhibition of dopaminergic neurite growth induced by treatment of rat VM neurons with the dopaminergic neurotoxin 6-hydroxydopamine (6-OHDA) in vitro is mediated by p38 and is concomitant with a significant and selective decrease in MKP-1 expression in these neurons. We further show that overexpression of MKP-1 in dopaminergic neurons contributes to neuroprotection against the effects of 6-OHDA. Collectively, we report that MKP-1 can promote the growth and elaboration of dopaminergic neuronal processes and can help protect them from the neurotoxic effects of 6-OHDA. Thus, we propose that strategies aimed at augmenting MKP-1 expression or activity may be beneficial in protecting dopaminergic neurons and may provide potential therapeutic approaches for PD.

  15. Sim1 Neurons Are Sufficient for MC4R-Mediated Sexual Function in Male Mice.

    Science.gov (United States)

    Semple, Erin; Hill, Jennifer W

    2018-01-01

    Sexual dysfunction is a poorly understood condition that affects up to one-third of men around the world. Existing treatments that target the periphery do not work for all men. Previous studies have shown that central melanocortins, which are released by pro-opiomelanocortin neurons in the arcuate nucleus of the hypothalamus, can lead to male erection and increased libido. Several studies specifically implicate the melanocortin 4 receptor (MC4R) in the central control of sexual function, but the specific neural circuitry involved is unknown. We hypothesized that single-minded homolog 1 (Sim1) neurons play an important role in the melanocortin-mediated regulation of male sexual behavior. To test this hypothesis, we examined the sexual behavior of mice expressing MC4R only on Sim1-positive neurons (tbMC4Rsim1 mice) in comparison with tbMC4R null mice and wild-type controls. In tbMC4Rsim1 mice, MC4R reexpression was found in the medial amygdala and paraventricular nucleus of the hypothalamus. These mice were paired with sexually experienced females, and their sexual function and behavior was scored based on mounting, intromission, and ejaculation. tbMC4R null mice showed a longer latency to mount, a reduced intromission efficiency, and an inability to reach ejaculation. Expression of MC4R only on Sim1 neurons reversed the sexual deficits seen in tbMC4R null mice. This study implicates melanocortin signaling via the MC4R on Sim1 neurons in the central control of male sexual behavior. Copyright © 2018 Endocrine Society.

  16. Advanced type 1 diabetes is associated with ASIC alterations in mouse lower thoracic dorsal root ganglia neurons.

    Science.gov (United States)

    Radu, Beatrice Mihaela; Dumitrescu, Diana Ionela; Marin, Adela; Banciu, Daniel Dumitru; Iancu, Adina Daniela; Selescu, Tudor; Radu, Mihai

    2014-01-01

    Acid-sensing ion channels (ASICs) from dorsal root ganglia (DRG) neurons are proton sensors during ischemia and inflammation. Little is known about their role in type 1 diabetes (T1D). Our study was focused on ASICs alterations determined by advanced T1D status. Primary neuronal cultures were obtained from lower (T9-T12) thoracic DRG neurons from Balb/c and TCR-HA(+/-)/Ins-HA(+/-) diabetic male mice (16 weeks of age). Patch-clamp recordings indicate a change in the number of small DRG neurons presenting different ASIC-type currents. Multiple molecular sites of ASICs are distinctly affected in T1D, probably due to particular steric constraints for glycans accessibility to the active site: (i) ASIC1 current inactivates faster, while ASIC2 is slower; (ii) PcTx1 partly reverts diabetes effects against ASIC1- and ASIC2-inactivations; (iii) APETx2 maintains unaltered potency against ASIC3 current amplitude, but slows ASIC3 inactivation. Immunofluorescence indicates opposite regulation of different ASIC transcripts while qRT-PCR shows that ASIC mRNA ranking (ASIC2 > ASIC1 > ASIC3) remains unaltered. In conclusion, our study has identified biochemical and biophysical ASIC changes in lower thoracic DRG neurons due to advanced T1D. As hypoalgesia is present in advanced T1D, ASICs alterations might be the cause or the consequence of diabetic insensate neuropathy.

  17. Roles for the VCP co-factors Npl4 and Ufd1 in neuronal function in Drosophila melanogaster.

    Science.gov (United States)

    Byrne, Dwayne J; Harmon, Mark J; Simpson, Jeremy C; Blackstone, Craig; O'Sullivan, Niamh C

    2017-10-20

    The VCP-Ufd1-Npl4 complex regulates proteasomal processing within cells by delivering ubiquitinated proteins to the proteasome for degradation. Mutations in VCP are associated with two neurodegenerative diseases, amyotrophic lateral sclerosis (ALS) and inclusion body myopathy with Paget's disease of the bone and frontotemporal dementia (IBMPFD), and extensive study has revealed crucial functions of VCP within neurons. By contrast, little is known about the functions of Npl4 or Ufd1 in vivo. Using neuronal-specific knockdown of Npl4 or Ufd1 in Drosophila melanogaster, we infer that Npl4 contributes to microtubule organization within developing motor neurons. Moreover, Npl4 RNAi flies present with neurodegenerative phenotypes including progressive locomotor deficits, reduced lifespan and increased accumulation of TAR DNA-binding protein-43 homolog (TBPH). Knockdown, but not overexpression, of TBPH also exacerbates Npl4 RNAi-associated adult-onset neurodegenerative phenotypes. In contrast, we find that neuronal knockdown of Ufd1 has little effect on neuromuscular junction (NMJ) organization, TBPH accumulation or adult behaviour. These findings suggest the differing neuronal functions of Npl4 and Ufd1 in vivo. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. SPARC and GluA1-Containing AMPA Receptors Promote Neuronal Health Following CNS Injury

    Directory of Open Access Journals (Sweden)

    Emma V. Jones

    2018-02-01

    Full Text Available The proper formation and maintenance of functional synapses in the central nervous system (CNS requires communication between neurons and astrocytes and the ability of astrocytes to release neuromodulatory molecules. Previously, we described a novel role for the astrocyte-secreted matricellular protein SPARC (Secreted Protein, Acidic and Rich in Cysteine in regulating α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs and plasticity at developing synapses. SPARC is highly expressed by astrocytes and microglia during CNS development but its level is reduced in adulthood. Interestingly, SPARC has been shown to be upregulated in CNS injury and disease. However, the role of SPARC upregulation in these contexts is not fully understood. In this study, we investigated the effect of chronic SPARC administration on glutamate receptors on mature hippocampal neuron cultures and following CNS injury. We found that SPARC treatment increased the number of GluA1-containing AMPARs at synapses and enhanced synaptic function. Furthermore, we determined that the increase in synaptic strength induced by SPARC could be inhibited by Philanthotoxin-433, a blocker of homomeric GluA1-containing AMPARs. We then investigated the effect of SPARC treatment on neuronal health in an injury context where SPARC expression is upregulated. We found that SPARC levels are increased in astrocytes and microglia following middle cerebral artery occlusion (MCAO in vivo and oxygen-glucose deprivation (OGD in vitro. Remarkably, chronic pre-treatment with SPARC prevented OGD-induced loss of synaptic GluA1. Furthermore, SPARC treatment reduced neuronal death through Philanthotoxin-433 sensitive GluA1 receptors. Taken together, this study suggests a novel role for SPARC and GluA1 in promoting neuronal health and recovery following CNS damage.

  19. Essential Roles for ARID1B in Dendritic Arborization and Spine Morphology of Developing Pyramidal Neurons

    Science.gov (United States)

    Ka, Minhan; Chopra, Divyan A.; Dravid, Shashank M.

    2016-01-01

    De novo truncating mutations in ARID1B, a chromatin-remodeling gene, cause Coffin–Siris syndrome, a developmental disorder characterized by intellectual disability and speech impairment; however, how the genetic elimination leads to cognitive dysfunction remains unknown. Thus, we investigated the neural functions of ARID1B during brain development. Here, we show that ARID1B regulates dendritic differentiation in the developing mouse brain. We knocked down ARID1B expression in mouse pyramidal neurons using in utero gene delivery methodologies. ARID1B knockdown suppressed dendritic arborization of cortical and hippocampal pyramidal neurons in mice. The abnormal development of dendrites accompanied a decrease in dendritic outgrowth into layer I. Furthermore, knockdown of ARID1B resulted in aberrant dendritic spines and synaptic transmission. Finally, ARID1B deficiency led to altered expression of c-Fos and Arc, and overexpression of these factors rescued abnormal differentiation induced by ARID1B knockdown. Our results demonstrate a novel role for ARID1B in neuronal differentiation and provide new insights into the origin of cognitive dysfunction associated with developmental intellectual disability. SIGNIFICANCE STATEMENT Haploinsufficiency of ARID1B, a component of chromatin remodeling complex, causes intellectual disability. However, the role of ARID1B in brain development is unknown. Here, we demonstrate that ARID1B is required for neuronal differentiation in the developing brain, such as in dendritic arborization and synapse formation. Our findings suggest that ARID1B plays a critical role in the establishment of cognitive circuitry by regulating dendritic complexity. Thus, ARID1B deficiency may cause intellectual disability via abnormal brain wiring induced by the defective differentiation of cortical neurons. PMID:26937011

  20. Treatment of trigeminal ganglion neurons in vitro with NGF, GDNF or BDNF: effects on neuronal survival, neurochemical properties and TRPV1-mediated neuropeptide secretion

    Directory of Open Access Journals (Sweden)

    Patwardhan Amol M

    2005-01-01

    Full Text Available Abstract Background Nerve growth factor (NGF, glial cell line-derived neurotrophic factor (GDNF and brain-derived neurotrophic factor (BDNF all play important roles in the development of the peripheral sensory nervous system. Additionally, these growth factors are proposed to modulate the properties of the sensory system in the adult under pathological conditions brought about by nerve injury or inflammation. We have examined the effects of NGF, GDNF and BDNF on adult rat trigeminal ganglion (TG neurons in culture to gain a better understanding of how these growth factors alter the cytochemical and functional phenotype of these neurons, with special attention to properties associated with nociception. Results Compared with no growth factor controls, GDNF, at 1 and 100 ng/ml, significantly increased by nearly 100% the number of neurons in culture at 5 days post-plating. A significant, positive, linear trend of increasing neuron number as a function of BDNF concentration was observed, also peaking at nearly 100%. NGF treatment was without effect. Chronic treatment with NGF and GDNF significantly and concentration-dependently increased 100 nM capsaicin (CAP-evoked calcitonin gene-related peptide (CGRP release, reaching approximately 300% at the highest concentration tested (100 ng/ml. Also, NGF and GDNF each augmented anandamide (AEA- and arachidonyl-2-chloroethylamide (ACEA-evoked CGRP release, while BDNF was without effect. Utilizing immunohistochemistry to account for the proportions of TRPV1- or CGRP-positive neurons under each growth factor treatment condition and then standardizing evoked CGRP release to these proportions, we observed that NGF was much more effective in enhancing CAP- and 50 mM K+-evoked CGRP release than was GDNF. Furthermore, NGF and GDNF each altered the concentration-response function for CAP- and AEA-evoked CGRP release, increasing the Emax without altering the EC50 for either compound. Conclusions Taken together, our

  1. A neuroprotective astrocyte state is induced by neuronal signal EphB1 but fails in ALS models.

    Science.gov (United States)

    Tyzack, Giulia E; Hall, Claire E; Sibley, Christopher R; Cymes, Tomasz; Forostyak, Serhiy; Carlino, Giulia; Meyer, Ione F; Schiavo, Giampietro; Zhang, Su-Chun; Gibbons, George M; Newcombe, Jia; Patani, Rickie; Lakatos, András

    2017-10-27

    Astrocyte responses to neuronal injury may be beneficial or detrimental to neuronal recovery, but the mechanisms that determine these different responses are poorly understood. Here we show that ephrin type-B receptor 1 (EphB1) is upregulated in injured motor neurons, which in turn can activate astrocytes through ephrin-B1-mediated stimulation of signal transducer and activator of transcription-3 (STAT3). Transcriptional analysis shows that EphB1 induces a protective and anti-inflammatory signature in astrocytes, partially linked to the STAT3 network. This is distinct from the response evoked by interleukin (IL)-6 that is known to induce both pro inflammatory and anti-inflammatory processes. Finally, we demonstrate that the EphB1-ephrin-B1 pathway is disrupted in human stem cell derived astrocyte and mouse models of amyotrophic lateral sclerosis (ALS). Our work identifies an early neuronal help-me signal that activates a neuroprotective astrocytic response, which fails in ALS, and therefore represents an attractive therapeutic target.

  2. Direct effects of glucose, insulin, GLP-1, and GIP on bulbospinal neurons in the rostral ventrolateral medulla in neonatal wistar rats.

    Science.gov (United States)

    Oshima, Naoki; Onimaru, Hiroshi; Matsubara, Hidehito; Uchida, Takahiro; Watanabe, Atsushi; Imakiire, Toshihiko; Nishida, Yasuhiro; Kumagai, Hiroo

    2017-03-06

    Although patients with diabetes mellitus (DM) often exhibit hypertension, the mechanisms responsible for this correlation are not well known. We hypothesized that the bulbospinal neurons in the rostral ventrolateral medulla (RVLM) are affected by the levels of glucose, insulin, or incretins (glucagon like peptide-1 [GLP-1] or glucose-dependent insulinotropic peptide [GIP]) in patients with DM. To investigate whether RVLM neurons are activated by glucose, insulin, GLP-1, or GIP, we examined changes in the membrane potentials of bulbospinal RVLM neurons using whole-cell patch-clamp technique during superfusion with various levels of glucose or these hormones in neonatal Wistar rats. A brainstem-spinal cord preparation was used for the experiments. A low level of glucose stimulated bulbospinal RVLM neurons. During insulin superfusion, almost all the RVLM neurons were depolarized, while during GLP-1 or GIP superfusion, almost all the RVLM neurons were hyperpolarized. Next, histological examinations were performed to examine transporters for glucose and receptors for insulin, GLP-1, and GIP on RVLM neurons. Low-level glucose-depolarized RVLM neurons exhibited the presence of glucose transporter 3 (GLUT3). Meanwhile, insulin-depolarized, GLP-1-hyperpolarized, and GIP-hyperpolarized RVLM neurons showed each of the respective specific receptor. These results indicate that a low level of glucose stimulates bulbospinal RVLM neurons via specific transporters on these neurons, inducing hypertension. Furthermore, an increase in insulin or a reduction in incretins may also activate the sympathetic nervous system and induce hypertension by activating RVLM neurons via their own receptors. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  3. Olfactory map formation in the Drosophila brain: genetic specificity and neuronal variability.

    Science.gov (United States)

    Brochtrup, Anna; Hummel, Thomas

    2011-02-01

    The development of the Drosophila olfactory system is a striking example of how genetic programs specify a large number of different neuron types and assemble them into functional circuits. To ensure precise odorant perception, each sensory neuron has to not only select a single olfactory receptor (OR) type out of a large genomic repertoire but also segregate its synaptic connections in the brain according to the OR class identity. Specification and patterning of second-order interneurons in the olfactory brain center occur largely independent of sensory input, followed by a precise point-to-point matching of sensory and relay neurons. Here we describe recent progress in the understanding of how cell-intrinsic differentiation programs and context-dependent cellular interactions generate a stereotyped sensory map in the Drosophila brain. Recent findings revealed an astonishing morphological diversity among members of the same interneuron class, suggesting an unexpected variability in local microcircuits involved in insect sensory processing. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Human Nav1.8: enhanced persistent and ramp currents contribute to distinct firing properties of human DRG neurons

    Science.gov (United States)

    Han, Chongyang; Estacion, Mark; Huang, Jianying; Vasylyev, Dymtro; Zhao, Peng; Dib-Hajj, Sulayman D.

    2015-01-01

    Although species-specific differences in ion channel properties are well-documented, little has been known about the properties of the human Nav1.8 channel, an important contributor to pain signaling. Here we show, using techniques that include voltage clamp, current clamp, and dynamic clamp in dorsal root ganglion (DRG) neurons, that human Nav1.8 channels display slower inactivation kinetics and produce larger persistent current and ramp current than previously reported in other species. DRG neurons expressing human Nav1.8 channels unexpectedly produce significantly longer-lasting action potentials, including action potentials with half-widths in some cells >10 ms, and increased firing frequency compared with the narrower and usually single action potentials generated by DRG neurons expressing rat Nav1.8 channels. We also show that native human DRG neurons recapitulate these properties of Nav1.8 current and the long-lasting action potentials. Together, our results demonstrate strikingly distinct properties of human Nav1.8, which contribute to the firing properties of human DRG neurons. PMID:25787950

  5. Β-amyloid 1-42 oligomers impair function of human embryonic stem cell-derived forebrain cholinergic neurons.

    Directory of Open Access Journals (Sweden)

    Linn Wicklund

    Full Text Available Cognitive impairment in Alzheimer's disease (AD patients is associated with a decline in the levels of growth factors, impairment of axonal transport and marked degeneration of basal forebrain cholinergic neurons (BFCNs. Neurogenesis persists in the adult human brain, and the stimulation of regenerative processes in the CNS is an attractive prospect for neuroreplacement therapy in neurodegenerative diseases such as AD. Currently, it is still not clear how the pathophysiological environment in the AD brain affects stem cell biology. Previous studies investigating the effects of the β-amyloid (Aβ peptide on neurogenesis have been inconclusive, since both neurogenic and neurotoxic effects on progenitor cell populations have been reported. In this study, we treated pluripotent human embryonic stem (hES cells with nerve growth factor (NGF as well as with fibrillar and oligomeric Aβ1-40 and Aβ1-42 (nM-µM concentrations and thereafter studied the differentiation in vitro during 28-35 days. The process applied real time quantitative PCR, immunocytochemistry as well as functional studies of intracellular calcium signaling. Treatment with NGF promoted the differentiation into functionally mature BFCNs. In comparison to untreated cells, oligomeric Aβ1-40 increased the number of functional neurons, whereas oligomeric Aβ1-42 suppressed the number of functional neurons. Interestingly, oligomeric Aβ exposure did not influence the number of hES cell-derived neurons compared with untreated cells, while in contrast fibrillar Aβ1-40 and Aβ1-42 induced gliogenesis. These findings indicate that Aβ1-42 oligomers may impair the function of stem cell-derived neurons. We propose that it may be possible for future AD therapies to promote the maturation of functional stem cell-derived neurons by altering the brain microenvironment with trophic support and by targeting different aggregation forms of Aβ.

  6. β1 integrin signaling promotes neuronal migration along vascular scaffolds in the post-stroke brain

    Directory of Open Access Journals (Sweden)

    Teppei Fujioka

    2017-02-01

    Full Text Available Cerebral ischemic stroke is a main cause of chronic disability. However, there is currently no effective treatment to promote recovery from stroke-induced neurological symptoms. Recent studies suggest that after stroke, immature neurons, referred to as neuroblasts, generated in a neurogenic niche, the ventricular-subventricular zone, migrate toward the injured area, where they differentiate into mature neurons. Interventions that increase the number of neuroblasts distributed at and around the lesion facilitate neuronal repair in rodent models for ischemic stroke, suggesting that promoting neuroblast migration in the post-stroke brain could improve efficient neuronal regeneration. To move toward the lesion, neuroblasts form chain-like aggregates and migrate along blood vessels, which are thought to increase their migration efficiency. However, the molecular mechanisms regulating these migration processes are largely unknown. Here we studied the role of β1-class integrins, transmembrane receptors for extracellular matrix proteins, in these migrating neuroblasts. We found that the neuroblast chain formation and blood vessel-guided migration critically depend on β1 integrin signaling. β1 integrin facilitated the adhesion of neuroblasts to laminin and the efficient translocation of their soma during migration. Moreover, artificial laminin-containing scaffolds promoted neuroblast chain formation and migration toward the injured area. These data suggest that laminin signaling via β1 integrin supports vasculature-guided neuronal migration to efficiently supply neuroblasts to injured areas. This study also highlights the importance of vascular scaffolds for cell migration in development and regeneration.

  7. Cerebral CBM1 neuron contributes to synaptic modulation appearing during rejection of seaweed in Aplysia kurodai.

    Science.gov (United States)

    Narusuye, Kenji; Nagahama, Tatsumi

    2002-11-01

    The Japanese species Aplysia kurodai feeds well on Ulva but rejects Gelidium with distinctive rhythmic patterned movements of the jaws and radula. We have previously shown that the patterned jaw movements during the rejection of Gelidium might be caused by long-lasting suppression of the monosynaptic transmission from the multiaction MA neurons to the jaw-closing (JC) motor neurons in the buccal ganglia and that the modulation might be directly produced by some cerebral neurons. In the present paper, we have identified a pair of catecholaminergic neurons (CBM1) in bilateral cerebral M clusters. The CBM1, probably equivalent to CBI-1 in A. californica, simultaneously produced monosynaptic excitatory postsynaptic potentials (EPSPs) in the MA and JC neurons. Firing of the CBM1 reduced the size of the inhibitory postsynaptic currents (IPSCs) in the JC neuron, evoked by the MA spikes, for >100 s. Moreover, the application of dopamine mimicked the CBM1 modulatory effects and pretreatment with a D1 antagonist, SCH23390, blocked the modulatory effects induced by dopamine. It could also largely block the modulatory effects induced by the CBM1 firing. These results suggest that the CBM1 may directly modulate the synaptic transmission by releasing dopamine. Moreover, we explored the CBM1 spike activity induced by taste stimulation of the animal lips with seaweed extracts by the use of calcium imaging. The calcium-sensitive dye, Calcium Green-1, was iontophoretically loaded into a cell body of the CBM1 using a microelectrode. Application of either Ulva or Gelidium extract to the lips increased the fluorescence intensity, but the Gelidium extract always induced a larger change in fluorescence compared with the Ulva extract, although the solution used induced the maximum spike responses of the CBM1 for each of the seaweed extracts. When the firing frequency of the CBM1 activity after taste stimulation was estimated, the Gelidium extract induced a spike activity of ~30 spikes

  8. Metabolic reprogramming during neuronal differentiation from aerobic glycolysis to neuronal oxidative phosphorylation.

    Science.gov (United States)

    Zheng, Xinde; Boyer, Leah; Jin, Mingji; Mertens, Jerome; Kim, Yongsung; Ma, Li; Ma, Li; Hamm, Michael; Gage, Fred H; Hunter, Tony

    2016-06-10

    How metabolism is reprogrammed during neuronal differentiation is unknown. We found that the loss of hexokinase (HK2) and lactate dehydrogenase (LDHA) expression, together with a switch in pyruvate kinase gene splicing from PKM2 to PKM1, marks the transition from aerobic glycolysis in neural progenitor cells (NPC) to neuronal oxidative phosphorylation. The protein levels of c-MYC and N-MYC, transcriptional activators of the HK2 and LDHA genes, decrease dramatically. Constitutive expression of HK2 and LDHA during differentiation leads to neuronal cell death, indicating that the shut-off aerobic glycolysis is essential for neuronal survival. The metabolic regulators PGC-1α and ERRγ increase significantly upon neuronal differentiation to sustain the transcription of metabolic and mitochondrial genes, whose levels are unchanged compared to NPCs, revealing distinct transcriptional regulation of metabolic genes in the proliferation and post-mitotic differentiation states. Mitochondrial mass increases proportionally with neuronal mass growth, indicating an unknown mechanism linking mitochondrial biogenesis to cell size.

  9. Activation of SF1 Neurons in the Ventromedial Hypothalamus by DREADD Technology Increases Insulin Sensitivity in Peripheral Tissues.

    Science.gov (United States)

    Coutinho, Eulalia A; Okamoto, Shiki; Ishikawa, Ayako Wendy; Yokota, Shigefumi; Wada, Nobuhiro; Hirabayashi, Takahiro; Saito, Kumiko; Sato, Tatsuya; Takagi, Kazuyo; Wang, Chen-Chi; Kobayashi, Kenta; Ogawa, Yoshihiro; Shioda, Seiji; Yoshimura, Yumiko; Minokoshi, Yasuhiko

    2017-09-01

    The ventromedial hypothalamus (VMH) regulates glucose and energy metabolism in mammals. Optogenetic stimulation of VMH neurons that express steroidogenic factor 1 (SF1) induces hyperglycemia. However, leptin acting via the VMH stimulates whole-body glucose utilization and insulin sensitivity in some peripheral tissues, and this effect of leptin appears to be mediated by SF1 neurons. We examined the effects of activation of SF1 neurons with DREADD (designer receptors exclusively activated by designer drugs) technology. Activation of SF1 neurons by an intraperitoneal injection of clozapine- N -oxide (CNO), a specific hM3Dq ligand, reduced food intake and increased energy expenditure in mice expressing hM3Dq in SF1 neurons. It also increased whole-body glucose utilization and glucose uptake in red-type skeletal muscle, heart, and interscapular brown adipose tissue, as well as glucose production and glycogen phosphorylase a activity in the liver, thereby maintaining blood glucose levels. During hyperinsulinemic-euglycemic clamp, such activation of SF1 neurons increased insulin-induced glucose uptake in the same peripheral tissues and tended to enhance insulin-induced suppression of glucose production by suppressing gluconeogenic gene expression and glycogen phosphorylase a activity in the liver. DREADD technology is thus an important tool for studies of the role of the brain in the regulation of insulin sensitivity in peripheral tissues. © 2017 by the American Diabetes Association.

  10. Neuronal-glial trafficking

    International Nuclear Information System (INIS)

    Bachelard, H.S.

    2001-01-01

    Full text: The name 'glia' originates from the Greek word for glue, because astro glia (or astrocytes) were thought only to provide an anatomical framework for the electrically-excitable neurones. However, awareness that astrocytes perform vital roles in protecting the neurones, which they surround, emerged from evidence that they act as neuroprotective K + -sinks, and that they remove potentially toxic extracellular glutamate from the vicinity of the neurones. The astrocytes convert the glutamate to non-toxic glutamine which is returned to the neurones and used to replenish transmitter glutamate. This 'glutamate-glutamine cycle' (established in the 1960s by Berl and his colleagues) also contributes to protecting the neurones against a build-up of toxic ammonia. Glial cells also supply the neurones with components for free-radical scavenging glutathione. Recent studies have revealed that glial cells play a more positive interactive role in furnishing the neurones with fuels. Studies using radioactive 14 C, 13 C-MRS and 15 N-GCMS have revealed that glia produce alanine, lactate and proline for consumption by neurones, with increased formation of neurotransmitter glutamate. On neuronal activation the release of NH 4 + and glutamate from the neurones stimulates glucose uptake and glycolysis in the glia to produce more alanine, which can be regarded as an 'alanine-glutamate cycle' Use of 14 C-labelled precursors provided early evidence that neurotransmitter GABA may be partly derived from glial glutamine, and this has been confirmed recently in vivo by MRS isotopomer analysis of the GABA and glutamine labelled from 13 C-acetate. Relative rates of intermediary metabolism in glia and neurones can be calculated using a combination of [1- 13 C] glucose and [1,2- 13 C] acetate. When glutamate is released by neurones there is a net neuronal loss of TCA intermediates which have to be replenished. Part of this is derived from carboxylation of pyruvate, (pyruvate carboxylase

  11. Transcriptional coupling of synaptic transmission and energy metabolism: role of nuclear respiratory factor 1 in co-regulating neuronal nitric oxide synthase and cytochrome c oxidase genes in neurons.

    Science.gov (United States)

    Dhar, Shilpa S; Liang, Huan Ling; Wong-Riley, Margaret T T

    2009-10-01

    Neuronal activity is highly dependent on energy metabolism; yet, the two processes have traditionally been regarded as independently regulated at the transcriptional level. Recently, we found that the same transcription factor, nuclear respiratory factor 1 (NRF-1) co-regulates an important energy-generating enzyme, cytochrome c oxidase, as well as critical subunits of glutamatergic receptors. The present study tests our hypothesis that the co-regulation extends to the next level of glutamatergic synapses, namely, neuronal nitric oxide synthase, which generates nitric oxide as a downstream signaling molecule. Using in silico analysis, electrophoretic mobility shift assay, chromatin immunoprecipitation, promoter mutations, and NRF-1 silencing, we documented that NRF-1 functionally bound to Nos1, but not Nos2 (inducible) and Nos3 (endothelial) gene promoters. Both COX and Nos1 transcripts were up-regulated by depolarizing KCl treatment and down-regulated by TTX-mediated impulse blockade in neurons. However, NRF-1 silencing blocked the up-regulation of both Nos1 and COX induced by KCl depolarization, and over-expression of NRF-1 rescued both Nos1 and COX transcripts down-regulated by TTX. These findings are consistent with our hypothesis that synaptic neuronal transmission and energy metabolism are tightly coupled at the molecular level.

  12. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity.

    Science.gov (United States)

    Shi, Xuemei; Chacko, Shaji; Li, Feng; Li, Depei; Burrin, Douglas; Chan, Lawrence; Guan, Xinfu

    2017-11-01

    Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose homeostasis. The objective of this study was to determine whether activation of PPG neurons per se modulates glucose homeostasis and insulin sensitivity in vivo. We generated glucagon (Gcg) promoter-driven Cre transgenic mice and injected excitatory hM3Dq-mCherry AAV into their brainstem NTS. We characterized the metabolic impact of PPG neuron activation on glucose homeostasis and insulin sensitivity using stable isotopic tracers coupled with hyperinsulinemic euglycemic clamp. We showed that after ip injection of clozapine N-oxide, Gcg-Cre lean mice transduced with hM3Dq in the brainstem NTS downregulated basal endogenous glucose production and enhanced glucose tolerance following ip glucose tolerance test. Moreover, acute activation of PPG neurons NTS enhanced whole-body insulin sensitivity as indicated by increased glucose infusion rate as well as augmented insulin-suppression of endogenous glucose production and gluconeogenesis. In contrast, insulin-stimulation of glucose disposal was not altered significantly. We conclude that acute activation of PPG neurons in the brainstem reduces basal glucose production, enhances intraperitoneal glucose tolerance, and augments hepatic insulin sensitivity, suggesting an important physiological role of PPG neurons-mediated circuitry in promoting glycemic control and insulin sensitivity. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  13. Regulation of autophagy by AMP-activated protein kinase/sirtuin 1 pathway reduces spinal cord neurons damage.

    Science.gov (United States)

    Yan, Peng; Bai, Liangjie; Lu, Wei; Gao, Yuzhong; Bi, Yunlong; Lv, Gang

    2017-09-01

    AMP-activated protein kinase/sirtuin 1 (AMPK/SIRT1) signaling pathway has been proved to be involved in the regulation of autophagy in various models. The aim of this study was to evaluate the effect of AMPK/SIRT1 pathway on autophagy after spinal cord injury (SCI). The SCI model was established in rats in vivo and the primary spinal cord neurons were subjected to mechanical injury (MI) in vitro . The apoptosis in spinal cord tissue and neurons was assessed by TUNEL staining and Hoechst 33342 staining, respectively. The autophagy-related proteins levels were detected by Western blot. The activation of AMPK/SIRT1 pathway was determined by Western blot and immunohistochemical staining. We found that the apoptosis of spinal cord tissue and cell damage of spinal cord neurons was obvious after the trauma. The ratio of LC3II/LC3I and level of p62 were first increased significantly and then decreased after the trauma in vivo and in vitro , indicating the defect in autophagy. The levels of p-AMPK and SIRT1 were increased obviously after the trauma in vivo and in vitro . Further activation of the AMPK/SIRT1 pathway by pretreatment with resveratrol, a confirmed activator of the AMPK/SIRT1 pathway, alleviated the cell damage and promoted the autophagy flux via downregulation of p62 in spinal cord neurons at 24 hr after MI. Our results demonstrate that regulation of autophagy by AMPK/SIRT1 pathway can restrain spinal cord neurons damage, which may be a potential intervention of SCI.

  14. Histamine Excites Rat Superior Vestibular Nuclear Neurons via Postsynaptic H1 and H2 Receptors in vitro

    Directory of Open Access Journals (Sweden)

    Qian-Xing Zhuang

    2012-09-01

    Full Text Available The superior vestibular nucleus (SVN, which holds a key position in vestibulo-ocular reflexes and nystagmus, receives direct hypothalamic histaminergic innervations. By using rat brainstem slice preparations and extracellular unitary recordings, we investigated the effect of histamine on SVN neurons and the underlying receptor mechanisms. Bath application of histamine evoked an excitatory response of the SVN neurons, which was not blocked by the low-Ca2+/high-Mg2+ medium, indicating a direct postsynaptic effect of the amine. Selective histamine H1 receptor agonist 2-pyridylethylamine and H2 receptor agonist dimaprit, rather than VUF8430, a selective H4 receptor agonist, mimicked the excitation of histamine on SVN neurons. In addition, selective H1 receptor antagonist mepyramine and H2 receptor antagonist ranitidine, but not JNJ7777120, a selective H4 receptor antagonist, partially blocked the excitatory response of SVN neurons to histamine. Moreover, mepyramine together with ranitidine nearly totally blocked the histamine-induced excitation. Immunostainings further showed that histamine H1 and H2 instead of H4 receptors existed in the SVN. These results demonstrate that histamine excites the SVN neurons via postsynaptic histamine H1 and H2 receptors, and suggest that the central histaminergic innervation from the hypothalamus may actively bias the SVN neuronal activity and subsequently modulate the SVN-mediated vestibular functions and gaze control.

  15. Layer 5 Callosal Parvalbumin-Expressing Neurons: A Distinct Functional Group of GABAergic Neurons.

    Science.gov (United States)

    Zurita, Hector; Feyen, Paul L C; Apicella, Alfonso Junior

    2018-01-01

    Previous studies have shown that parvalbumin-expressing neurons (CC-Parv neurons) connect the two hemispheres of motor and sensory areas via the corpus callosum, and are a functional part of the cortical circuit. Here we test the hypothesis that layer 5 CC-Parv neurons possess anatomical and molecular mechanisms which dampen excitability and modulate the gating of interhemispheric inhibition. In order to investigate this hypothesis we use viral tracing to determine the anatomical and electrophysiological properties of layer 5 CC-Parv and parvalbumin-expressing (Parv) neurons of the mouse auditory cortex (AC). Here we show that layer 5 CC-Parv neurons had larger dendritic fields characterized by longer dendrites that branched farther from the soma, whereas layer 5 Parv neurons had smaller dendritic fields characterized by shorter dendrites that branched nearer to the soma. The layer 5 CC-Parv neurons are characterized by delayed action potential (AP) responses to threshold currents, lower firing rates, and lower instantaneous frequencies compared to the layer 5 Parv neurons. Kv1.1 containing K + channels are the main source of the AP repolarization of the layer 5 CC-Parv and have a major role in determining both the spike delayed response, firing rate and instantaneous frequency of these neurons.

  16. Sodium/bicarbonate cotransporter NBCn1/slc4a7 increases cytotoxicity in magnesium depletion in primary cultures of hippocampal neurons

    Science.gov (United States)

    Cooper, Deborah S.; Yang, Han Soo; He, Peijian; Kim, Eunjin; Rajbhandari, Ira; Yun, Chris C.; Choi, Inyeong

    2009-01-01

    Growing evidence suggests that pharmacological inhibition of Na/H exchange and Na/HCO3 transport provides protection against damage or injury in cardiac ischemia. In this study, we examined the contribution of the sodium/bicarbonate cotransporter NBCn1 (slc4a7) to cytotoxicity in cultured hippocampal neurons of rats. In neurons exposed to extracellular pH (pHo) ranging from 6.2 to 8.3, NBCn1 protein expression increased by fivefold at pH < 6.5 compared to the expression at pHo 7.4. At pHo 6.5, the intracellular pH of neurons was ~1 unit lower than that at pH 7.4. Immunochemistry showed a marked increase in NBCn1 immunofluorescence in plasma membranes and cytosol of the soma as well as in dendrites, at pHo 6.5. NBCn1 expression also increased by 40% in a prolonged Mg2+-free incubation at normal pHo. Knockdown of NBCn1 in neurons had negligible effect on cell viability. The effect of NBCn1 knockdown on cytotoxicity was then determined by exposing neurons to 0.5 mM glutamate for 10 min and measuring lactate dehydrogenase (LDH) release from neurons. Compared to normal incubation (pHo 7.2 for 6 h) after glutamate exposure, acidic incubation (pHo 6.3 for 6 h) reduced cytotoxicity by 75% for control neurons and 78% for NBCn1-knockdown neurons. Thus, both controls and knockdown neurons showed acidic protection from cytotoxicity. However, in Mg2+-free incubation after glutamate exposure, NBCn1 knockdown progressively attenuated cytotoxicity. This attenuation was unaffected by acidic preincubation before glutamate exposure. We conclude that NBCn1 has a dynamic upregulation in low pHo and Mg2+ depletion. NBCn1 is not required for acidic protection, but increases cytotoxicity in Mg2+-free conditions. PMID:19170751

  17. Nesfatin-1 activates cardiac vagal neurons of nucleus ambiguus and elicits bradycardia in conscious rats.

    Science.gov (United States)

    Brailoiu, G Cristina; Deliu, Elena; Tica, Andrei A; Rabinowitz, Joseph E; Tilley, Douglas G; Benamar, Khalid; Koch, Walter J; Brailoiu, Eugen

    2013-09-01

    Nesfatin-1, a peptide whose receptor is yet to be identified, has been involved in the modulation of feeding, stress, and metabolic responses. More recently, increasing evidence supports a modulatory role for nesfatin-1 in autonomic and cardiovascular activity. This study was undertaken to test if the expression of nesfatin-1 in the nucleus ambiguus, a key site for parasympathetic cardiac control, may be correlated with a functional role. As we have previously demonstrated that nesfatin-1 elicits Ca²⁺ signaling in hypothalamic neurons, we first assessed the effect of this peptide on cytosolic Ca²⁺ in cardiac pre-ganglionic neurons of nucleus ambiguus. We provide evidence that nesfatin-1 increases cytosolic Ca²⁺ concentration via a Gi/o-coupled mechanism. The nesfatin-1-induced Ca²⁺ rise is critically dependent on Ca²⁺ influx via P/Q-type voltage-activated Ca²⁺ channels. Repeated administration of nesfatin-1 leads to tachyphylaxis. Furthermore, nesfatin-1 produces a dose-dependent depolarization of cardiac vagal neurons via a Gi/o-coupled mechanism. In vivo studies, using telemetric and tail-cuff monitoring of heart rate and blood pressure, indicate that microinjection of nesfatin-1 into the nucleus ambiguus produces bradycardia not accompanied by a change in blood pressure in conscious rats. Taken together, our results identify for the first time that nesfatin-1 decreases heart rate by activating cardiac vagal neurons of nucleus ambiguus. Our results indicate that nesfatin-1, one of the most potent feeding peptides, increases cytosolic Ca²⁺ by promoting Ca²⁺ influx via P/Q channels and depolarizes nucleus ambiguus neurons; both effects are Gi/o-mediated. In vivo studies indicate that microinjection of nesfatin-1 into nucleus ambiguus produces bradycardia in conscious rats. This is the first report that nesfatin-1 increases the parasympathetic cardiac tone. © 2013 International Society for Neurochemistry.

  18. 31 CFR 560.803 - Customs procedures: Goods specified in § 560.201.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Customs procedures: Goods specified... REGULATIONS Procedures § 560.803 Customs procedures: Goods specified in § 560.201. (a) With respect to goods... Customs officers shall not accept or allow any: (1) Entry for consumption or warehouse (including any...

  19. Contextual Learning Requires Functional Diversity at Excitatory and Inhibitory Synapses onto CA1 Pyramidal Neurons

    Directory of Open Access Journals (Sweden)

    Dai Mitsushima

    2015-01-01

    Full Text Available Although the hippocampus is processing temporal and spatial information in particular context, the encoding rule creating memory is completely unknown. To examine the mechanism, we trained rats on an inhibitory avoidance (IA task, a hippocampus-dependent rapid one-trial contextual learning paradigm. By combining Herpes virus-mediated in vivo gene delivery with in vitro patch-clamp recordings, I reported contextual learning drives GluR1-containing AMPA receptors into CA3-CA1 synapses. The molecular event is required for contextual memory, since bilateral expression of delivery blocker in CA1 successfully blocked IA learning. Moreover, I found a logarithmic correlation between the number of delivery blocking cells and learning performance. Considering that one all-or-none device can process 1-bit of data per clock (Nobert Wiener 1961, the logarithmic correlation may provides evidence that CA1 neurons transmit essential data of contextual information. Further, I recently reported critical role of acetylcholine as an intrinsic trigger of learning-dependent synaptic plasticity. IA training induced ACh release in CA1 that strengthened not only AMPA receptor-mediated excitatory synapses, but also GABAA receptor-mediated inhibitory synapses on each CA1 neuron. More importantly, IA-trained rats showed individually different excitatory and inhibitory synaptic inputs with wide variation on each CA1 neuron. Here I propose a new hypothesis that the diversity of synaptic inputs on CA1 neurons may depict cell-specific outputs processing experienced episodes after training.

  20. ApoSOD1 lacking dismutase activity neuroprotects motor neurons exposed to beta-methylamino-L-alanine through the Ca2+/Akt/ERK1/2 prosurvival pathway

    Science.gov (United States)

    Petrozziello, Tiziana; Secondo, Agnese; Tedeschi, Valentina; Esposito, Alba; Sisalli, MariaJosè; Scorziello, Antonella; Di Renzo, Gianfranco; Annunziato, Lucio

    2017-01-01

    Amyotrophic lateral sclerosis (ALS) is a severe human adult-onset neurodegenerative disease affecting lower and upper motor neurons. In >20% of cases, the familial form of ALS is caused by mutations in the gene encoding Cu,Zn-superoxide dismutase (SOD1). Interestingly, administration of wild-type SOD1 to SOD1G93A transgenic rats ameliorates motor symptoms through an unknown mechanism. Here we investigated whether the neuroprotective effects of SOD1 are due to the Ca2+-dependent activation of such prosurvival signaling pathway and not to its catalytic activity. To this aim, we also examined the mechanism of neuroprotective action of ApoSOD1, the metal-depleted state of SOD1 that lacks dismutase activity, in differentiated motor neuron-like NSC-34 cells and in primary motor neurons exposed to the cycad neurotoxin beta-methylamino-L-alanine (L-BMAA). Preincubation of ApoSOD1 and SOD1, but not of human recombinant SOD1G93A, prevented cell death in motor neurons exposed to L-BMAA. Moreover, ApoSOD1 elicited ERK1/2 and Akt phosphorylation in motor neurons through an early increase of intracellular Ca2+ concentration ([Ca2+]i). Accordingly, inhibition of ERK1/2 by siMEK1 and PD98059 counteracted ApoSOD1- and SOD1-induced neuroprotection. Similarly, transfection of the dominant-negative form of Akt in NSC-34 motor neurons and treatment with the selective PI3K inhibitor LY294002 prevented ApoSOD1- and SOD1-mediated neuroprotective effects in L-BMAA-treated motor neurons. Furthermore, ApoSOD1 and SOD1 prevented the expression of the two markers of L-BMAA-induced ER stress GRP78 and caspase-12. Collectively, our data indicate that ApoSOD1, which is devoid of any catalytic dismutase activity, exerts a neuroprotective effect through an early activation of Ca2+/Akt/ERK1/2 pro-survival pathway that, in turn, prevents ER stress in a neurotoxic model of ALS. PMID:28085149

  1. Identification of a subset of perpheral T-cell lymphoma, not otherwise specified, characterized by FOXP3-positive regulatory T-cell phenotype, HTLV-1 negativity and poor outcome

    DEFF Research Database (Denmark)

    Pedersen, Martin Bjerregård; Hamilton-Dutoit, Stephen Jacques; Bendix, Knud

    2014-01-01

    Identification of a subset of perpheral T-cell lymphoma, not otherwise specified, characterized by FOXP3-positive regulatory T-cell phenotype, HTLV-1 negativity and poor outcome.......Identification of a subset of perpheral T-cell lymphoma, not otherwise specified, characterized by FOXP3-positive regulatory T-cell phenotype, HTLV-1 negativity and poor outcome....

  2. Ribosomal S6K1 in POMC and AgRP Neurons Regulates Glucose Homeostasis but Not Feeding Behavior in Mice

    Directory of Open Access Journals (Sweden)

    Mark A. Smith

    2015-04-01

    Full Text Available Hypothalamic ribosomal S6K1 has been suggested as a point of convergence for hormonal and nutrient signals in the regulation of feeding behavior, bodyweight, and glucose metabolism. However, the long-term effects of manipulating hypothalamic S6K1 signaling on energy homeostasis and the cellular mechanisms underlying these roles are unclear. We therefore inactivated S6K1 in pro-opiomelanocortin (POMC and agouti-related protein (AgRP neurons, key regulators of energy homeostasis, but in contrast to the current view, we found no evidence that S6K1 regulates food intake and bodyweight. In contrast, S6K1 signaling in POMC neurons regulated hepatic glucose production and peripheral lipid metabolism and modulated neuronal excitability. S6K1 signaling in AgRP neurons regulated skeletal muscle insulin sensitivity and was required for glucose sensing by these neurons. Our findings suggest that S6K1 signaling is not a general integrator of energy homeostasis in the mediobasal hypothalamus but has distinct roles in the regulation of glucose homeostasis by POMC and AgRP neurons.

  3. BlastNeuron for Automated Comparison, Retrieval and Clustering of 3D Neuron Morphologies.

    Science.gov (United States)

    Wan, Yinan; Long, Fuhui; Qu, Lei; Xiao, Hang; Hawrylycz, Michael; Myers, Eugene W; Peng, Hanchuan

    2015-10-01

    Characterizing the identity and types of neurons in the brain, as well as their associated function, requires a means of quantifying and comparing 3D neuron morphology. Presently, neuron comparison methods are based on statistics from neuronal morphology such as size and number of branches, which are not fully suitable for detecting local similarities and differences in the detailed structure. We developed BlastNeuron to compare neurons in terms of their global appearance, detailed arborization patterns, and topological similarity. BlastNeuron first compares and clusters 3D neuron reconstructions based on global morphology features and moment invariants, independent of their orientations, sizes, level of reconstruction and other variations. Subsequently, BlastNeuron performs local alignment between any pair of retrieved neurons via a tree-topology driven dynamic programming method. A 3D correspondence map can thus be generated at the resolution of single reconstruction nodes. We applied BlastNeuron to three datasets: (1) 10,000+ neuron reconstructions from a public morphology database, (2) 681 newly and manually reconstructed neurons, and (3) neurons reconstructions produced using several independent reconstruction methods. Our approach was able to accurately and efficiently retrieve morphologically and functionally similar neuron structures from large morphology database, identify the local common structures, and find clusters of neurons that share similarities in both morphology and molecular profiles.

  4. Astrocytes protect neurons against methylmercury via ATP/P2Y(1) receptor-mediated pathways in astrocytes.

    Science.gov (United States)

    Noguchi, Yusuke; Shinozaki, Youichi; Fujishita, Kayoko; Shibata, Keisuke; Imura, Yoshio; Morizawa, Yosuke; Gachet, Christian; Koizumi, Schuichi

    2013-01-01

    Methylmercury (MeHg) is a well known environmental pollutant that induces serious neuronal damage. Although MeHg readily crosses the blood-brain barrier, and should affect both neurons and glial cells, how it affects glia or neuron-to-glia interactions has received only limited attention. Here, we report that MeHg triggers ATP/P2Y1 receptor signals in astrocytes, thereby protecting neurons against MeHg via interleukin-6 (IL-6)-mediated pathways. MeHg increased several mRNAs in astrocytes, among which IL-6 was the highest. For this, ATP/P2Y1 receptor-mediated mechanisms were required because the IL-6 production was (i) inhibited by a P2Y1 receptor antagonist, MRS2179, (ii) abolished in astrocytes obtained from P2Y1 receptor-knockout mice, and (iii) mimicked by exogenously applied ATP. In addition, (iv) MeHg released ATP by exocytosis from astrocytes. As for the intracellular mechanisms responsible for IL-6 production, p38 MAP kinase was involved. MeHg-treated astrocyte-conditioned medium (ACM) showed neuro-protective effects against MeHg, which was blocked by anti-IL-6 antibody and was mimicked by the application of recombinant IL-6. As for the mechanism of neuro-protection by IL-6, an adenosine A1 receptor-mediated pathway in neurons seems to be involved. Taken together, when astrocytes sense MeHg, they release ATP that autostimulates P2Y1 receptors to upregulate IL-6, thereby leading to A1 receptor-mediated neuro-protection against MeHg.

  5. GPER1 mediates estrogen-induced neuroprotection against oxygen-glucose deprivation in the primary hippocampal neurons.

    Science.gov (United States)

    Zhao, Tian-Zhi; Shi, Fei; Hu, Jun; He, Shi-Ming; Ding, Qian; Ma, Lian-Ting

    2016-07-22

    It is well-known that the neuroprotective effects of estrogen have potential in the prevention and amelioration of ischemic and degenerative neurological disorders, while the underlying mechanisms for estrogen actions are undefined. As an important mediator for the non-genomic functions of estrogen, GPER1 (G Protein-coupled Estrogen Receptor 1) has been suggested to involve in the beneficial roles of estrogen in neural cells. Here our studies on primary hippocampal neurons have focused on GPER1 in an in vitro model of ischemia using oxygen-glucose deprivation (OGD). GPER1 expression in the primary hippocampal neurons was stimulated by the OGD treatments. Both E2 (estradiol) and E2-BSA (membrane impermeable estradiol by covalent conjugation of bovine serum albumin) attenuated OGD-induced cell death in primary cultures of hippocampal neurons. Importantly, this membrane-mediated estrogen function requires GPER1 protein. Knocking down of GPER1 diminished, while overexpression of GPER1 potentiated, the protective roles of E2/E2-BSA following OGD. Additionally, the downstream mechanisms employed by membrane-associated estrogen signaling were found to include PI3K/Akt-dependent Ask1 inhibition in the primary hippocampal neurons. Overall, these research results could enhance our understanding of the neuroprotective actions for estrogen, and provide a new therapeutic target for improving stroke outcome and ameliorating degenerative neurological diseases. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  6. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity

    OpenAIRE

    Xuemei Shi; Shaji Chacko; Feng Li; Depei Li; Douglas Burrin; Lawrence Chan; Xinfu Guan

    2017-01-01

    Objective: Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose homeostasis. The objective of this study was to determine whether activation of PPG neurons per se modulates glucose homeostasis and insulin sensitivity in vivo. Methods: We generated glucagon (Gcg) promoter-driven Cre transgenic mice and injected...

  7. Dysregulated Expression of Neuregulin-1 by Cortical Pyramidal Neurons Disrupts Synaptic Plasticity

    Directory of Open Access Journals (Sweden)

    Amit Agarwal

    2014-08-01

    Full Text Available Neuregulin-1 (NRG1 gene variants are associated with increased genetic risk for schizophrenia. It is unclear whether risk haplotypes cause elevated or decreased expression of NRG1 in the brains of schizophrenia patients, given that both findings have been reported from autopsy studies. To study NRG1 functions in vivo, we generated mouse mutants with reduced and elevated NRG1 levels and analyzed the impact on cortical functions. Loss of NRG1 from cortical projection neurons resulted in increased inhibitory neurotransmission, reduced synaptic plasticity, and hypoactivity. Neuronal overexpression of cysteine-rich domain (CRD-NRG1, the major brain isoform, caused unbalanced excitatory-inhibitory neurotransmission, reduced synaptic plasticity, abnormal spine growth, altered steady-state levels of synaptic plasticity-related proteins, and impaired sensorimotor gating. We conclude that an “optimal” level of NRG1 signaling balances excitatory and inhibitory neurotransmission in the cortex. Our data provide a potential pathomechanism for impaired synaptic plasticity and suggest that human NRG1 risk haplotypes exert a gain-of-function effect.

  8. Dysregulated expression of neuregulin-1 by cortical pyramidal neurons disrupts synaptic plasticity.

    Science.gov (United States)

    Agarwal, Amit; Zhang, Mingyue; Trembak-Duff, Irina; Unterbarnscheidt, Tilmann; Radyushkin, Konstantin; Dibaj, Payam; Martins de Souza, Daniel; Boretius, Susann; Brzózka, Magdalena M; Steffens, Heinz; Berning, Sebastian; Teng, Zenghui; Gummert, Maike N; Tantra, Martesa; Guest, Peter C; Willig, Katrin I; Frahm, Jens; Hell, Stefan W; Bahn, Sabine; Rossner, Moritz J; Nave, Klaus-Armin; Ehrenreich, Hannelore; Zhang, Weiqi; Schwab, Markus H

    2014-08-21

    Neuregulin-1 (NRG1) gene variants are associated with increased genetic risk for schizophrenia. It is unclear whether risk haplotypes cause elevated or decreased expression of NRG1 in the brains of schizophrenia patients, given that both findings have been reported from autopsy studies. To study NRG1 functions in vivo, we generated mouse mutants with reduced and elevated NRG1 levels and analyzed the impact on cortical functions. Loss of NRG1 from cortical projection neurons resulted in increased inhibitory neurotransmission, reduced synaptic plasticity, and hypoactivity. Neuronal overexpression of cysteine-rich domain (CRD)-NRG1, the major brain isoform, caused unbalanced excitatory-inhibitory neurotransmission, reduced synaptic plasticity, abnormal spine growth, altered steady-state levels of synaptic plasticity-related proteins, and impaired sensorimotor gating. We conclude that an "optimal" level of NRG1 signaling balances excitatory and inhibitory neurotransmission in the cortex. Our data provide a potential pathomechanism for impaired synaptic plasticity and suggest that human NRG1 risk haplotypes exert a gain-of-function effect. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  9. The neurotoxicant PCB-95 by increasing the neuronal transcriptional repressor REST down-regulates caspase-8 and increases Ripk1, Ripk3 and MLKL expression determining necroptotic neuronal death.

    Science.gov (United States)

    Guida, Natascia; Laudati, Giusy; Serani, Angelo; Mascolo, Luigi; Molinaro, Pasquale; Montuori, Paolo; Di Renzo, Gianfranco; Canzoniero, Lorella M T; Formisano, Luigi

    2017-10-15

    Our previous study showed that the environmental neurotoxicant non-dioxin-like polychlorinated biphenyl (PCB)-95 increases RE1-silencing transcription factor (REST) expression, which is related to necrosis, but not apoptosis, of neurons. Meanwhile, necroptosis is a type of a programmed necrosis that is positively regulated by receptor interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain-like (MLKL) and negatively regulated by caspase-8. Here we evaluated whether necroptosis contributes to PCB-95-induced neuronal death through REST up-regulation. Our results demonstrated that in cortical neurons PCB-95 increased RIPK1, RIPK3, and MLKL expression and decreased caspase-8 at the gene and protein level. Furthermore, the RIPK1 inhibitor necrostatin-1 or siRNA-mediated RIPK1, RIPK3 and MLKL expression knockdown significantly reduced PCB-95-induced neuronal death. Intriguingly, PCB-95-induced increases in RIPK1, RIPK3, MLKL expression and decreases in caspase-8 expression were reversed by knockdown of REST expression with a REST-specific siRNA (siREST). Notably, in silico analysis of the rat genome identified a REST consensus sequence in the caspase-8 gene promoter (Casp8-RE1), but not the RIPK1, RIPK3 and MLKL promoters. Interestingly, in PCB-95-treated neurons, REST binding to the Casp8-RE1 sequence increased in parallel with a reduction in its promoter activity, whereas under the same experimental conditions, transfection of siREST or mutation of the Casp8-RE1 sequence blocked PCB-95-induced caspase-8 reduction. Since RIPK1, RIPK3 and MLKL rat genes showed no putative REST binding site, we assessed whether the transcription factor cAMP Responsive Element Binding Protein (CREB), which has a consensus sequence in all three genes, affected neuronal death. In neurons treated with PCB-95, CREB protein expression decreased in parallel with a reduction in binding to the RIPK1, RIPK3 and MLKL gene promoter sequence. Furthermore, CREB overexpression was

  10. PINK1 regulates mitochondrial trafficking in dendrites of cortical neurons through mitochondrial PKA.

    Science.gov (United States)

    Das Banerjee, Tania; Dagda, Raul Y; Dagda, Marisela; Chu, Charleen T; Rice, Monica; Vazquez-Mayorga, Emmanuel; Dagda, Ruben K

    2017-08-01

    Mitochondrial Protein Kinase A (PKA) and PTEN-induced kinase 1 (PINK1), which is linked to Parkinson's disease, are two neuroprotective serine/threonine kinases that regulate dendrite remodeling and mitochondrial function. We have previously shown that PINK1 regulates dendrite morphology by enhancing PKA activity. Here, we show the molecular mechanisms by which PINK1 and PKA in the mitochondrion interact to regulate dendrite remodeling, mitochondrial morphology, content, and trafficking in dendrites. PINK1-deficient cortical neurons exhibit impaired mitochondrial trafficking, reduced mitochondrial content, fragmented mitochondria, and a reduction in dendrite outgrowth compared to wild-type neurons. Transient expression of wild-type, but not a PKA-binding-deficient mutant of the PKA-mitochondrial scaffold dual-specificity A Kinase Anchoring Protein 1 (D-AKAP1), restores mitochondrial trafficking, morphology, and content in dendrites of PINK1-deficient cortical neurons suggesting that recruiting PKA to the mitochondrion reverses mitochondrial pathology in dendrites induced by loss of PINK1. Mechanistically, full-length and cleaved forms of PINK1 increase the binding of the regulatory subunit β of PKA (PKA/RIIβ) to D-AKAP1 to enhance the autocatalytic-mediated phosphorylation of PKA/RIIβ and PKA activity. D-AKAP1/PKA governs mitochondrial trafficking in dendrites via the Miro-2/TRAK2 complex and by increasing the phosphorylation of Miro-2. Our study identifies a new role of D-AKAP1 in regulating mitochondrial trafficking through Miro-2, and supports a model in which PINK1 and mitochondrial PKA participate in a similar neuroprotective signaling pathway to maintain dendrite connectivity. © 2017 International Society for Neurochemistry.

  11. TBC1D24 regulates neuronal migration and maturation through modulation of the ARF6-dependent pathway

    Science.gov (United States)

    Falace, Antonio; Buhler, Emmanuelle; Fadda, Manuela; Watrin, Françoise; Lippiello, Pellegrino; Pallesi-Pocachard, Emilie; Baldelli, Pietro; Benfenati, Fabio; Zara, Federico; Represa, Alfonso; Fassio, Anna; Cardoso, Carlos

    2014-01-01

    Alterations in the formation of brain networks are associated with several neurodevelopmental disorders. Mutations in TBC1 domain family member 24 (TBC1D24) are responsible for syndromes that combine cortical malformations, intellectual disability, and epilepsy, but the function of TBC1D24 in the brain remains unknown. We report here that in utero TBC1D24 knockdown in the rat developing neocortex affects the multipolar-bipolar transition of neurons leading to delayed radial migration. Furthermore, we find that TBC1D24-knockdown neurons display an abnormal maturation and retain immature morphofunctional properties. TBC1D24 interacts with ADP ribosylation factor (ARF)6, a small GTPase crucial for membrane trafficking. We show that in vivo, overexpression of the dominant-negative form of ARF6 rescues the neuronal migration and dendritic outgrowth defects induced by TBC1D24 knockdown, suggesting that TBC1D24 prevents ARF6 activation. Overall, our findings demonstrate an essential role of TBC1D24 in neuronal migration and maturation and highlight the physiological relevance of the ARF6-dependent membrane-trafficking pathway in brain development. PMID:24469796

  12. Regulation of autophagy by AMP-activated protein kinase/ sirtuin 1 pathway reduces spinal cord neurons damage

    Directory of Open Access Journals (Sweden)

    Peng Yan

    2017-09-01

    Full Text Available Objective(s: AMP-activated protein kinase/sirtuin 1 (AMPK/SIRT1 signaling pathway has been proved to be involved in the regulation of autophagy in various models. The aim of this study was to evaluate the effect of AMPK/SIRT1 pathway on autophagy after spinal cord injury (SCI. Materials and Methods:The SCI model was established in rats in vivo and the primary spinal cord neurons were subjected to mechanical injury (MI in vitro. The apoptosis in spinal cord tissue and neurons was assessed by TUNEL staining and Hoechst 33342 staining, respectively. The autophagy-related proteins levels were detected by Western blot. The activation of AMPK/SIRT1 pathway was determined by Western blot and immunohistochemical staining. Results: We found that the apoptosis of spinal cord tissue and cell damage of spinal cord neurons was obvious after the trauma. The ratio of LC3II/LC3I and level of p62 were first increased significantly and then decreased after the trauma in vivo and in vitro, indicating the defect in autophagy. The levels of p-AMPK and SIRT1 were increased obviously after the trauma in vivo and in vitro. Further activation of the AMPK/SIRT1 pathway by pretreatment with resveratrol, a confirmed activator of the AMPK/SIRT1 pathway, alleviated the cell damage and promoted the autophagy flux via downregulation of p62 in spinal cord neurons at 24 hr after MI. Conclusion: Our results demonstrate that regulation of autophagy by AMPK/SIRT1 pathway can restrain spinal cord neurons damage, which may be a potential intervention of SCI.

  13. The spinal muscular atrophy with pontocerebellar hypoplasia gene VRK1 regulates neuronal migration through an amyloid-β precursor protein-dependent mechanism.

    Science.gov (United States)

    Vinograd-Byk, Hadar; Sapir, Tamar; Cantarero, Lara; Lazo, Pedro A; Zeligson, Sharon; Lev, Dorit; Lerman-Sagie, Tally; Renbaum, Paul; Reiner, Orly; Levy-Lahad, Ephrat

    2015-01-21

    Spinal muscular atrophy with pontocerebellar hypoplasia (SMA-PCH) is an infantile SMA variant with additional manifestations, particularly severe microcephaly. We previously identified a nonsense mutation in Vaccinia-related kinase 1 (VRK1), R358X, as a cause of SMA-PCH. VRK1-R358X is a rare founder mutation in Ashkenazi Jews, and additional mutations in patients of different origins have recently been identified. VRK1 is a nuclear serine/threonine protein kinase known to play multiple roles in cellular proliferation, cell cycle regulation, and carcinogenesis. However, VRK1 was not known to have neuronal functions before its identification as a gene mutated in SMA-PCH. Here we show that VRK1-R358X homozygosity results in lack of VRK1 protein, and demonstrate a role for VRK1 in neuronal migration and neuronal stem cell proliferation. Using shRNA in utero electroporation in mice, we show that Vrk1 knockdown significantly impairs cortical neuronal migration, and affects the cell cycle of neuronal progenitors. Expression of wild-type human VRK1 rescues both proliferation and migration phenotypes. However, kinase-dead human VRK1 rescues only the migration impairment, suggesting the role of VRK1 in neuronal migration is partly noncatalytic. Furthermore, we found that VRK1 deficiency in human and mouse leads to downregulation of amyloid-β precursor protein (APP), a known neuronal migration gene. APP overexpression rescues the phenotype caused by Vrk1 knockdown, suggesting that VRK1 affects neuronal migration through an APP-dependent mechanism. Copyright © 2015 the authors 0270-6474/15/350936-08$15.00/0.

  14. TRANSGENIC GDNF POSITIVELY INFLUENCES PROLIFERATION, DIFFERENTIATION, MATURATION AND SURVIVAL OF MOTOR NEURONS PRODUCED FROM MOUSE EMBRYONIC STEM CELLS.

    Directory of Open Access Journals (Sweden)

    Daniel Édgar Cortés

    2016-09-01

    Full Text Available Embryonic stem cells (ESC are pluripotent and thus can differentiate into every cell type present in the body. Directed differentiation into motor neurons has been described for pluripotent cells. Although neurotrophic factors promote neuronal survival, their role in neuronal commitment is elusive. Here, we developed double-transgenic lines of mouse ESC that constitutively produce Glial cell-derived neurotrophic factor (GDNF and also contain a GFP reporter, driven by HB9, which is expressed only by postmitotic motor neurons. After lentiviral transduction, ESC lines integrated and expressed the human GDNF gene without altering pluripotency markers before differentiation. Further, GDNF-ESC showed significantly higher spontaneous release of this neurotrophin to the medium, when compared to controls. To study motor neuron induction, control and GDNF cell lines were grown as embryoid bodies and stimulated with retinoic acid and Sonic Hedgehog. In GDNF-overexpressing cells, a significant increase of proliferative Olig2+ precursors, which are specified as spinal motor neurons, was found. Accordingly, GDNF increases the yield of cells with the pan motor neuronal markers HB9, monitored by GFP expression, and Isl1. At terminal differentiation, almost all differentiated neurons express phenotypic markers of motor neurons in GDNF cultures, with lower proportions in control cells. To test if the effects of GDNF were present at early differentiation stages, exogenous recombinant human GDNF was added to control ESC, also resulting in enhanced motor neuron differentiation. This effect was abolished by the co-addition of neutralizing anti-GDNF antibodies, strongly suggesting that differentiating ESC are responsive to GDNF. Using the HB9::GFP reporter, motor neurons were selected for electrophysiological recordings. Motor neurons differentiated from GDNF-ESC, compared to control motor neurons, showed greater electrophysiological maturation, characterized by

  15. Effects of DISC1 Polymorphisms on Resting-State Spontaneous Neuronal Activity in the Early-Stage of Schizophrenia

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    Ningzhi Gou

    2018-05-01

    Full Text Available Background: Localized abnormalities in the synchrony of spontaneous neuronal activity, measured with regional homogeneity (ReHo, has been consistently reported in patients with schizophrenia (SCZ and their unaffected siblings. To date, little is known about the genetic influences affecting the spontaneous neuronal activity in SCZ. DISC1, a strong susceptible gene for SCZ, has been implicated in neuronal excitability and synaptic function possibly associated with regional spontaneous neuronal activity. This study aimed to examine the effects of DISC1 variations on the regional spontaneous neuronal activity in SCZ.Methods: Resting-state fMRI data were obtained from 28 SCZ patients and 21 healthy controls (HC for ReHo analysis. Six single nucleotide polymorphisms (SNPs of DISC1 gene were genotyped using the PCR and direct sequencing.Results: Significant diagnosis × genotype interactions were noted for three SNPs (rs821616, rs821617, and rs2738880. For rs821617, the interactions were localized to the precuneus, basal ganglia and pre-/post-central regions. Significant interactive effects were identified at the temporal and post-central gyri for rs821616 (Ser704Cys and the inferior temporal gyrus for rs2738880. Furthermore, post-hoc analysis revealed that the DISC1 variations on these SNPs exerted different influences on ReHo between SCZ patients and HC.Conclusion: To our knowledge this is the first study to unpick the influence of DISC1 variations on spontaneous neuronal activity in SCZ; Given the emerging evidence that ReHo is a stable inheritable phenotype for schizophrenia, our findings suggest the DISC1 variations are possibly an inheritable source for the altered ReHo in this disorder.

  16. Human Na(v)1.8: enhanced persistent and ramp currents contribute to distinct firing properties of human DRG neurons.

    Science.gov (United States)

    Han, Chongyang; Estacion, Mark; Huang, Jianying; Vasylyev, Dymtro; Zhao, Peng; Dib-Hajj, Sulayman D; Waxman, Stephen G

    2015-05-01

    Although species-specific differences in ion channel properties are well-documented, little has been known about the properties of the human Nav1.8 channel, an important contributor to pain signaling. Here we show, using techniques that include voltage clamp, current clamp, and dynamic clamp in dorsal root ganglion (DRG) neurons, that human Na(v)1.8 channels display slower inactivation kinetics and produce larger persistent current and ramp current than previously reported in other species. DRG neurons expressing human Na(v)1.8 channels unexpectedly produce significantly longer-lasting action potentials, including action potentials with half-widths in some cells >10 ms, and increased firing frequency compared with the narrower and usually single action potentials generated by DRG neurons expressing rat Na(v)1.8 channels. We also show that native human DRG neurons recapitulate these properties of Na(v)1.8 current and the long-lasting action potentials. Together, our results demonstrate strikingly distinct properties of human Na(v)1.8, which contribute to the firing properties of human DRG neurons.

  17. Ribosomal S6K1 in POMC and AgRP Neurons Regulates Glucose Homeostasis but Not Feeding Behavior in Mice.

    Science.gov (United States)

    Smith, Mark A; Katsouri, Loukia; Irvine, Elaine E; Hankir, Mohammed K; Pedroni, Silvia M A; Voshol, Peter J; Gordon, Matthew W; Choudhury, Agharul I; Woods, Angela; Vidal-Puig, Antonio; Carling, David; Withers, Dominic J

    2015-04-21

    Hypothalamic ribosomal S6K1 has been suggested as a point of convergence for hormonal and nutrient signals in the regulation of feeding behavior, bodyweight, and glucose metabolism. However, the long-term effects of manipulating hypothalamic S6K1 signaling on energy homeostasis and the cellular mechanisms underlying these roles are unclear. We therefore inactivated S6K1 in pro-opiomelanocortin (POMC) and agouti-related protein (AgRP) neurons, key regulators of energy homeostasis, but in contrast to the current view, we found no evidence that S6K1 regulates food intake and bodyweight. In contrast, S6K1 signaling in POMC neurons regulated hepatic glucose production and peripheral lipid metabolism and modulated neuronal excitability. S6K1 signaling in AgRP neurons regulated skeletal muscle insulin sensitivity and was required for glucose sensing by these neurons. Our findings suggest that S6K1 signaling is not a general integrator of energy homeostasis in the mediobasal hypothalamus but has distinct roles in the regulation of glucose homeostasis by POMC and AgRP neurons. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  18. TLX activates MASH1 for induction of neuronal lineage commitment of adult hippocampal neuroprogenitors.

    Science.gov (United States)

    Elmi, Muna; Matsumoto, Yoshiki; Zeng, Zhao-jun; Lakshminarasimhan, Pavithra; Yang, Weiwen; Uemura, Akiyoshi; Nishikawa, Shin-ichi; Moshiri, Alicia; Tajima, Nobuyoshi; Agren, Hans; Funa, Keiko

    2010-10-01

    The orphan nuclear receptor TLX has been proposed to act as a repressor of cell cycle inhibitors to maintain the neural stem cells in an undifferentiated state, and prevents commitment into astrocyte lineages. However, little is known about the mechanism of TLX in neuronal lineage commitment and differentiation. A majority of adult rat hippocampus-derived progenitors (AHPs) cultured in the presence of FGF express a high level of TLX and a fraction of these cells also express the proneural gene MASH1. Upon FGF withdrawal, TLX rapidly decreased, while MASH1 was intensely expressed within 1h, decreasing gradually to disappear at 24h. Adenoviral transduction of TLX in AHP cells in the absence of FGF transiently increased cell proliferation, however, later resulted in neuronal differentiation by inducing MASH1, Neurogenin1, DCX, and MAP2ab. Furthermore, TLX directly targets and activates the MASH1 promoter through interaction with Sp1, recruiting co-activators whereas dismissing the co-repressor HDAC4. Conversely, silencing of TLX in AHPs decreased beta-III tubulin and DCX expression and promoted glial differentiation. Our results thus suggest that TLX not only acts as a repressor of cell cycle and glial differentiation but also activates neuronal lineage commitment in AHPs. Copyright 2010 Elsevier Inc. All rights reserved.

  19. Effects of weak electric fields on the activity of neurons and neuronal networks

    International Nuclear Information System (INIS)

    Jeffreys, J.G.R.; Deans, J.; Bikson, M.; Fox, J.

    2003-01-01

    Electric fields applied to brain tissue will affect cellular properties. They will hyperpolarise the ends of cells closest to the positive part of the field, and depolarise ends closest to the negative. In the case of neurons this affects excitability. How these changes in transmembrane potential are distributed depends on the length constant of the neuron, and on its geometry; if the neuron is electrically compact, the change in transmembrane potential becomes an almost linear function of distance in the direction of the field. Neurons from the mammalian hippocampus, maintained in tissue slices in vitro, are significantly affected by fields of around 1-5 Vm -1 . (author)

  20. A role for the tyrosine kinase ACK1 in neurotrophin signaling and neuronal extension and branching

    Science.gov (United States)

    La Torre, A; del Mar Masdeu, M; Cotrufo, T; Moubarak, R S; del Río, J A; Comella, J X; Soriano, E; Ureña, J M

    2013-01-01

    Neurotrophins are involved in many crucial cellular functions, including neurite outgrowth, synapse formation, and plasticity. Although these events have long been known, the molecular determinants underlying neuritogenesis have not been fully characterized. Ack1 (activated Cdc42-associated tyrosine kinase) is a non-receptor tyrosine kinase that is highly expressed in the brain. Here, we demonstrate that Ack1 is a molecular constituent of neurotrophin signaling cascades in neurons and PC12 cells. We report that Ack1 interacts with Trk receptors and becomes tyrosine phosphorylated and its kinase activity is increased in response to neurotrophins. Moreover, our data indicate that Ack1 acts upstream of the Akt and MAPK pathways. We show that Ack1 overexpression induces neuritic outgrowth and promotes branching in neurotrophin-treated neuronal cells, whereas the expression of Ack1 dominant negatives or short-hairpin RNAs counteract neurotrophin-stimulated differentiation. Our results identify Ack1 as a novel regulator of neurotrophin-mediated events in primary neurons and in PC12 cells. PMID:23598414

  1. Neuronal SH2B1 is essential for controlling energy and glucose homeostasis.

    Science.gov (United States)

    Ren, Decheng; Zhou, Yingjiang; Morris, David; Li, Minghua; Li, Zhiqin; Rui, Liangyou

    2007-02-01

    SH2B1 (previously named SH2-B), a cytoplasmic adaptor protein, binds via its Src homology 2 (SH2) domain to a variety of protein tyrosine kinases, including JAK2 and the insulin receptor. SH2B1-deficient mice are obese and diabetic. Here we demonstrated that multiple isoforms of SH2B1 (alpha, beta, gamma, and/or delta) were expressed in numerous tissues, including the brain, hypothalamus, liver, muscle, adipose tissue, heart, and pancreas. Rat SH2B1beta was specifically expressed in neural tissue in SH2B1-transgenic (SH2B1(Tg)) mice. SH2B1(Tg) mice were crossed with SH2B1-knockout (SH2B1(KO)) mice to generate SH2B1(TgKO) mice expressing SH2B1 only in neural tissue but not in other tissues. Systemic deletion of the SH2B1 gene resulted in metabolic disorders in SH2B1(KO) mice, including hyperlipidemia, leptin resistance, hyperphagia, obesity, hyperglycemia, insulin resistance, and glucose intolerance. Neuron-specific restoration of SH2B1beta not only corrected the metabolic disorders in SH2B1(TgKO) mice, but also improved JAK2-mediated leptin signaling and leptin regulation of orexigenic neuropeptide expression in the hypothalamus. Moreover, neuron-specific overexpression of SH2B1 dose-dependently protected against high-fat diet-induced leptin resistance and obesity. These observations suggest that neuronal SH2B1 regulates energy balance, body weight, peripheral insulin sensitivity, and glucose homeostasis at least in part by enhancing hypothalamic leptin sensitivity.

  2. Metabolic reprogramming during neuronal differentiation.

    Science.gov (United States)

    Agostini, M; Romeo, F; Inoue, S; Niklison-Chirou, M V; Elia, A J; Dinsdale, D; Morone, N; Knight, R A; Mak, T W; Melino, G

    2016-09-01

    Newly generated neurons pass through a series of well-defined developmental stages, which allow them to integrate into existing neuronal circuits. After exit from the cell cycle, postmitotic neurons undergo neuronal migration, axonal elongation, axon pruning, dendrite morphogenesis and synaptic maturation and plasticity. Lack of a global metabolic analysis during early cortical neuronal development led us to explore the role of cellular metabolism and mitochondrial biology during ex vivo differentiation of primary cortical neurons. Unexpectedly, we observed a huge increase in mitochondrial biogenesis. Changes in mitochondrial mass, morphology and function were correlated with the upregulation of the master regulators of mitochondrial biogenesis, TFAM and PGC-1α. Concomitant with mitochondrial biogenesis, we observed an increase in glucose metabolism during neuronal differentiation, which was linked to an increase in glucose uptake and enhanced GLUT3 mRNA expression and platelet isoform of phosphofructokinase 1 (PFKp) protein expression. In addition, glutamate-glutamine metabolism was also increased during the differentiation of cortical neurons. We identified PI3K-Akt-mTOR signalling as a critical regulator role of energy metabolism in neurons. Selective pharmacological inhibition of these metabolic pathways indicate existence of metabolic checkpoint that need to be satisfied in order to allow neuronal differentiation.

  3. Cyclophosphamide-induced cystitis reduces ASIC channel but enhances TRPV1 receptor function in rat bladder sensory neurons.

    Science.gov (United States)

    Dang, Khoa; Bielefeldt, Klaus; Gebhart, G F

    2013-07-01

    Using patch-clamp techniques, we studied the plasticity of acid-sensing ion channels (ASIC) and transient receptor potential V1 (TRPV1) channel function in dorsal root ganglia (DRG) neurons retrogradely labeled from the bladder. Saline (control) or cyclophosphamide (CYP) was given intraperitoneally on days 1, 3, and 5. On day 6, lumbosacral (LS, L6-S2) or thoracolumbar (TL, T13-L2) DRG were removed and dissociated. Bladders and bladder DRG neurons from CYP-treated rats showed signs of inflammation (greater myeloperoxidase activity; lower intramuscular wall pH) and increased size (whole cell capacitance), respectively, compared with controls. Most bladder neurons (>90%) responded to protons and capsaicin. Protons produced multiphasic currents with distinct kinetics, whereas capsaicin always triggered a sustained response. The TRPV1 receptor antagonist A-425619 abolished capsaicin-triggered currents and raised the threshold of heat-activated currents. Prolonged exposure to an acidic environment (pH range: 7.2 to 6.6) inhibited proton-evoked currents, potentiated the capsaicin-evoked current, and reduced the threshold of heat-activated currents in LS and TL bladder neurons. CYP treatment reduced density but not kinetics of all current components triggered by pH 5. In contrast, CYP-treatment was associated with an increased current density in response to capsaicin in LS and TL bladder neurons. Correspondingly, heat triggered current at a significantly lower temperature in bladder neurons from CYP-treated rats compared with controls. These results reveal that cystitis differentially affects TRPV1- and ASIC-mediated currents in both bladder sensory pathways. Acidification of the bladder wall during inflammation may contribute to changes in nociceptive transmission mediated through the TRPV1 receptor, suggesting a role for TRPV1 in hypersensitivity associated with cystitis.

  4. Increased transient Na+ conductance and action potential output in layer 2/3 prefrontal cortex neurons of the fmr1-/y mouse.

    Science.gov (United States)

    Routh, Brandy N; Rathour, Rahul K; Baumgardner, Michael E; Kalmbach, Brian E; Johnston, Daniel; Brager, Darrin H

    2017-07-01

    Layer 2/3 neurons of the prefrontal cortex display higher gain of somatic excitability, responding with a higher number of action potentials for a given stimulus, in fmr1 -/y mice. In fmr1 -/y L2/3 neurons, action potentials are taller, faster and narrower. Outside-out patch clamp recordings revealed that the maximum Na + conductance density is higher in fmr1 -/y L2/3 neurons. Measurements of three biophysically distinct K + currents revealed a depolarizing shift in the activation of a rapidly inactivating (A-type) K + conductance. Realistic neuronal simulations of the biophysical observations recapitulated the elevated action potential and repetitive firing phenotype. Fragile X syndrome is the most common form of inherited mental impairment and autism. The prefrontal cortex is responsible for higher order cognitive processing, and prefrontal dysfunction is believed to underlie many of the cognitive and behavioural phenotypes associated with fragile X syndrome. We recently demonstrated that somatic and dendritic excitability of layer (L) 5 pyramidal neurons in the prefrontal cortex of the fmr1 -/y mouse is significantly altered due to changes in several voltage-gated ion channels. In addition to L5 pyramidal neurons, L2/3 pyramidal neurons play an important role in prefrontal circuitry, integrating inputs from both lower brain regions and the contralateral cortex. Using whole-cell current clamp recording, we found that L2/3 pyramidal neurons in prefrontal cortex of fmr1 -/y mouse fired more action potentials for a given stimulus compared with wild-type neurons. In addition, action potentials in fmr1 -/y neurons were significantly larger, faster and narrower. Voltage clamp of outside-out patches from L2/3 neurons revealed that the transient Na + current was significantly larger in fmr1 -/y neurons. Furthermore, the activation curve of somatic A-type K + current was depolarized. Realistic conductance-based simulations revealed that these biophysical changes in Na

  5. Regulatory role of neuron-restrictive silencing factor in expression of TRPC1

    International Nuclear Information System (INIS)

    Ohba, Takayoshi; Watanabe, Hiroyuki; Takahashi, Yoichiro; Suzuki, Takashi; Miyoshi, Ichiro; Nakayama, Shinnsuke; Satoh, Eisaku; Iino, Kenji; Sasano, Hironobu; Mori, Yasuo; Kuromitsu, Sadao; Imagawa, Keiichi; Saito, Yoshihiko; Iijima, Toshihiko; Ito, Hiroshi; Murakami, Manabu

    2006-01-01

    Neuron-restrictive silencer factor (NRSF) binds its consensus element to repress the transcription of various genes. The dominant-negative form (dnNRSF) has a hypertrophic effect on cardiogenesis through an unidentified mechanism. We examined the involvement of transient receptor potential (TRP) channel proteins, using transgenic mice overexpressing dnNRSF (dnNRSF mice). Electrophoretic mobility-shift assays revealed an interaction between NRSF and a neuron-restrictive silencer element-like sequence in intron 4 of TRPC1 genomic DNA. According to RT-PCR and Western analyses, TRPC1 was up-regulated in dnNRSF mouse heart. Transient overexpression of TRPC1 in HEK 293T cells increased the activity of the nuclear factor in activated T cells (NFAT) promoter and stimulated store-operated Ca 2+ channel (SOCC)-mediated Ca 2+ entry. Transfection of TRPC1 into primary cardiomyocytes increased NFAT activity, indicating a major role for TRPC1 in NFAT activation. Our findings strongly suggest that NRSF regulates TRP1 gene expression and causes changes in the levels of calcium entry through SOCCs

  6. Dorsal-CA1 Hippocampal Neuronal Ensembles Encode Nicotine-Reward Contextual Associations.

    Science.gov (United States)

    Xia, Li; Nygard, Stephanie K; Sobczak, Gabe G; Hourguettes, Nicholas J; Bruchas, Michael R

    2017-06-06

    Natural and drug rewards increase the motivational valence of stimuli in the environment that, through Pavlovian learning mechanisms, become conditioned stimuli that directly motivate behavior in the absence of the original unconditioned stimulus. While the hippocampus has received extensive attention for its role in learning and memory processes, less is known regarding its role in drug-reward associations. We used in vivo Ca 2+ imaging in freely moving mice during the formation of nicotine preference behavior to examine the role of the dorsal-CA1 region of the hippocampus in encoding contextual reward-seeking behavior. We show the development of specific neuronal ensembles whose activity encodes nicotine-reward contextual memories and that are necessary for the expression of place preference. Our findings increase our understanding of CA1 hippocampal function in general and as it relates to reward processing by identifying a critical role for CA1 neuronal ensembles in nicotine place preference. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  7. [Study of neuron-protective effect and mechanism of neuregulin1β against cerebral ischemia reperfusion-induced injury in rats].

    Science.gov (United States)

    Ji, Y Q; Zhang, R; Teng, L; Li, H Y; Guo, Y L

    2017-07-18

    Objective: Thecurrent study is to explore the neuron-protective mechanism of neuregulin1β (NRG1β) in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R) through inhibiting the c-Jun phosphorylation. Methods: After 24 h of MCAO/R (referring to Longa's method), neurobehavioral function was measured by modified neurological severity score (mNSS) test; the cerebral infarction volume was detected by triphenyltetrazolium chloride (TTC) staining; the blood brain barrier (BBB) permeability was measured by Evans Blue (EB); the neuron morphology of brain tissue was observed by Nissl stain; the ultra-structures of the neurons were observed by transmission electron microscopy (TEM); the apoptotic neurons were counted by in situ cell death detection kit colocalized with NeuN; the expressions of phospho-c-Jun was determined by immunofluorescent labeling and Western blot analysis. Results: Compared with the sham-operation rats, the rats receiving MCAO/R showed increased mNSS (9.7±1.2), cerebral infarction volume (41.4±3.0)%, permeability of BBB, deformation of neurons, ischemia-induced apoptosis (0.63±0.04), and enhanced expression of phospho-c-Jun protein (0.90±0.07) (all P <0.05). Our data indicated that NRG1β attenuated neurologic deficits (6.4±0.9), decreased the cerebral infarction volume (10.4±0.5), reduced EB extravasation (1.55±0.13) and the deformation of neurons, protected the ultra-structure of neurons, blocked ischemia-induced apoptosis (0.23±0.02), through down-regulated phospho-c-Jun expression (0.40±0.03) in MCAO/R rats ( P <0.05). Conclusion: NRG1β exerts neuron-protective effects against ischemia reperfusion-induced injury in rats through inhibiting the c-Jun phosphorylation.

  8. Tbx1 and Jag1 act in concert to modulate the fate of neurosensory cells of the mouse otic vesicle

    Directory of Open Access Journals (Sweden)

    Stephania Macchiarulo

    2017-10-01

    Full Text Available The domain within the otic vesicle (OV known as the neurosensory domain (NSD, contains cells that will give rise to the hair and support cells of the otic sensory organs, as well as the neurons that form the cochleovestibular ganglion (CVG. The molecular dynamics that occur at the NSD boundary relative to adjacent OV cells is not well defined. The Tbx1 transcription factor gene expression pattern is complementary to the NSD, and inactivation results in expansion of the NSD and expression of the Notch ligand, Jag1 mapping, in part of the NSD. To shed light on the role of Jag1 in NSD development, as well as to test whether Tbx1 and Jag1 might genetically interact to regulate this process, we inactivated Jag1 within the Tbx1 expression domain using a knock-in Tbx1Cre allele. We observed an enlarged neurogenic domain marked by a synergistic increase in expression of NeuroD and other proneural transcription factor genes in double Tbx1 and Jag1 conditional loss-of-function embryos. We noted that neuroblasts preferentially expanded across the medial-lateral axis and that an increase in cell proliferation could not account for this expansion, suggesting that there was a change in cell fate. We also found that inactivation of Jag1 with Tbx1Cre resulted in failed development of the cristae and semicircular canals, as well as notably fewer hair cells in the ventral epithelium of the inner ear rudiment when inactivated on a Tbx1 null background, compared to Tbx1Cre/− mutant embryos. We propose that loss of expression of Tbx1 and Jag1 within the Tbx1 expression domain tips the balance of cell fates in the NSD, resulting in an overproduction of neuroblasts at the expense of non-neural cells within the OV.

  9. PROS-1/Prospero Is a Major Regulator of the Glia-Specific Secretome Controlling Sensory-Neuron Shape and Function in C. elegans.

    Science.gov (United States)

    Wallace, Sean W; Singhvi, Aakanksha; Liang, Yupu; Lu, Yun; Shaham, Shai

    2016-04-19

    Sensory neurons are an animal's gateway to the world, and their receptive endings, the sites of sensory signal transduction, are often associated with glia. Although glia are known to promote sensory-neuron functions, the molecular bases of these interactions are poorly explored. Here, we describe a post-developmental glial role for the PROS-1/Prospero/PROX1 homeodomain protein in sensory-neuron function in C. elegans. Using glia expression profiling, we demonstrate that, unlike previously characterized cell fate roles, PROS-1 functions post-embryonically to control sense-organ glia-specific secretome expression. PROS-1 functions cell autonomously to regulate glial secretion and membrane structure, and non-cell autonomously to control the shape and function of the receptive endings of sensory neurons. Known glial genes controlling sensory-neuron function are PROS-1 targets, and we identify additional PROS-1-dependent genes required for neuron attributes. Drosophila Prospero and vertebrate PROX1 are expressed in post-mitotic sense-organ glia and astrocytes, suggesting conserved roles for this class of transcription factors. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Cooperative transcription activation by Nurr1 and Pitx3 induces embryonic stem cell maturation to the midbrain dopamine neuron phenotype

    DEFF Research Database (Denmark)

    Martinat, Cecile; Bacci, Jean-Jacques; Leete, Thomas

    2006-01-01

    's disease. We sought to identify genes that can potentiate maturation of ES cell cultures to the midbrain DA neuron phenotype. A number of transcription factors have been implicated in the development of midbrain DA neurons by expression analyses and loss-of-function knockout mouse studies, including Nurr1......Midbrain dopamine (DA) neurons play a central role in the regulation of voluntary movement, and their degeneration is associated with Parkinson's disease. Cell replacement therapies, and in particular embryonic stem (ES) cell-derived DA neurons, offer a potential therapeutic venue for Parkinson......, Pitx3, Lmx1b, Engrailed-1, and Engrailed-2. However, none of these factors appear sufficient alone to induce the mature midbrain DA neuron phenotype in ES cell cultures in vitro, suggesting a more complex regulatory network. Here we show that Nurr1 and Pitx3 cooperatively promote terminal maturation...

  11. The Molecular Motor KIF1A Transports the TrkA Neurotrophin Receptor and Is Essential for Sensory Neuron Survival and Function.

    Science.gov (United States)

    Tanaka, Yosuke; Niwa, Shinsuke; Dong, Ming; Farkhondeh, Atena; Wang, Li; Zhou, Ruyun; Hirokawa, Nobutaka

    2016-06-15

    KIF1A is a major axonal transport motor protein, but its functional significance remains elusive. Here we show that KIF1A-haploinsufficient mice developed sensory neuropathy. We found progressive loss of TrkA(+) sensory neurons in Kif1a(+/-) dorsal root ganglia (DRGs). Moreover, axonal transport of TrkA was significantly disrupted in Kif1a(+/-) neurons. Live imaging and immunoprecipitation assays revealed that KIF1A bound to TrkA-containing vesicles through the adaptor GTP-Rab3, suggesting that TrkA is a cargo of the KIF1A motor. Physiological measurements revealed a weaker capsaicin response in Kif1a(+/-) DRG neurons. Moreover, these neurons were hyposensitive to nerve growth factor, which could explain the reduced neuronal survival and the functional deficiency of the pain receptor TRPV1. Because phosphatidylinositol 3-kinase (PI3K) signaling significantly rescued these phenotypes and also increased Kif1a mRNA, we propose that KIF1A is essential for the survival and function of sensory neurons because of the TrkA transport and its synergistic support of the NGF/TrkA/PI3K signaling pathway. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Heavy metals in locus ceruleus and motor neurons in motor neuron disease.

    Science.gov (United States)

    Pamphlett, Roger; Kum Jew, Stephen

    2013-12-12

    The causes of sporadic amyotrophic lateral sclerosis (SALS) and other types of motor neuron disease (MND) remain largely unknown. Heavy metals have long been implicated in MND, and it has recently been shown that inorganic mercury selectively enters human locus ceruleus (LC) and motor neurons. We therefore used silver nitrate autometallography (AMG) to look for AMG-stainable heavy metals (inorganic mercury and bismuth) in LC and motor neurons of 24 patients with MND (18 with SALS and 6 with familial MND) and in the LC of 24 controls. Heavy metals in neurons were found in significantly more MND patients than in controls when comparing: (1) the presence of any versus no heavy metal-containing LC neurons (MND 88%, controls 42%), (2) the median percentage of heavy metal-containing LC neurons (MND 9.5%, control 0.0%), and (3) numbers of individuals with heavy metal-containing LC neurons in the upper half of the percentage range (MND 75%, controls 25%). In MND patients, 67% of remaining spinal motor neurons contained heavy metals; smaller percentages were found in hypoglossal, nucleus ambiguus and oculomotor neurons, but none in cortical motor neurons. The majority of MND patients had heavy metals in both LC and spinal motor neurons. No glia or other neurons, including neuromelanin-containing neurons of the substantia nigra, contained stainable heavy metals. Uptake of heavy metals by LC and lower motor neurons appears to be fairly common in humans, though heavy metal staining in the LC, most likely due to inorganic mercury, was seen significantly more often in MND patients than in controls. The LC innervates many cell types that are affected in MND, and it is possible that MND is triggered by toxicant-induced interactions between LC and motor neurons.

  13. Heavy metals in locus ceruleus and motor neurons in motor neuron disease

    Science.gov (United States)

    2013-01-01

    Background The causes of sporadic amyotrophic lateral sclerosis (SALS) and other types of motor neuron disease (MND) remain largely unknown. Heavy metals have long been implicated in MND, and it has recently been shown that inorganic mercury selectively enters human locus ceruleus (LC) and motor neurons. We therefore used silver nitrate autometallography (AMG) to look for AMG-stainable heavy metals (inorganic mercury and bismuth) in LC and motor neurons of 24 patients with MND (18 with SALS and 6 with familial MND) and in the LC of 24 controls. Results Heavy metals in neurons were found in significantly more MND patients than in controls when comparing: (1) the presence of any versus no heavy metal-containing LC neurons (MND 88%, controls 42%), (2) the median percentage of heavy metal-containing LC neurons (MND 9.5%, control 0.0%), and (3) numbers of individuals with heavy metal-containing LC neurons in the upper half of the percentage range (MND 75%, controls 25%). In MND patients, 67% of remaining spinal motor neurons contained heavy metals; smaller percentages were found in hypoglossal, nucleus ambiguus and oculomotor neurons, but none in cortical motor neurons. The majority of MND patients had heavy metals in both LC and spinal motor neurons. No glia or other neurons, including neuromelanin-containing neurons of the substantia nigra, contained stainable heavy metals. Conclusions Uptake of heavy metals by LC and lower motor neurons appears to be fairly common in humans, though heavy metal staining in the LC, most likely due to inorganic mercury, was seen significantly more often in MND patients than in controls. The LC innervates many cell types that are affected in MND, and it is possible that MND is triggered by toxicant-induced interactions between LC and motor neurons. PMID:24330485

  14. An ancient neurotrophin receptor code; a single Runx/Cbfβ complex determines somatosensory neuron fate specification in zebrafish.

    Science.gov (United States)

    Gau, Philia; Curtright, Andrew; Condon, Logan; Raible, David W; Dhaka, Ajay

    2017-07-01

    In terrestrial vertebrates such as birds and mammals, neurotrophin receptor expression is considered fundamental for the specification of distinct somatosensory neuron types where TrkA, TrkB and TrkC specify nociceptors, mechanoceptors and proprioceptors/mechanoceptors, respectively. In turn, Runx transcription factors promote neuronal fate specification by regulating neurotrophin receptor and sensory receptor expression where Runx1 mediates TrkA+ nociceptor diversification while Runx3 promotes a TrkC+ proprioceptive/mechanoceptive fate. Here, we report in zebrafish larvae that orthologs of the neurotrophin receptors in contrast to terrestrial vertebrates mark overlapping and distinct subsets of nociceptors suggesting that TrkA, TrkB and TrkC do not intrinsically promote nociceptor, mechanoceptor and proprioceptor/mechanoceptor neuronal fates, respectively. While we find that zebrafish Runx3 regulates nociceptors in contrast to terrestrial vertebrates, it shares a conserved regulatory mechanism found in terrestrial vertebrate proprioceptors/mechanoceptors in which it promotes TrkC expression and suppresses TrkB expression. We find that Cbfβ, which enhances Runx protein stability and affinity for DNA, serves as an obligate cofactor for Runx in neuronal fate determination. High levels of Runx can compensate for the loss of Cbfβ, indicating that in this context Cbfβ serves solely as a signal amplifier of Runx activity. Our data suggests an alteration/expansion of the neurotrophin receptor code of sensory neurons between larval teleost fish and terrestrial vertebrates, while the essential roles of Runx/Cbfβ in sensory neuron cell fate determination while also expanded are conserved.

  15. NBLAST: Rapid, Sensitive Comparison of Neuronal Structure and Construction of Neuron Family Databases.

    Science.gov (United States)

    Costa, Marta; Manton, James D; Ostrovsky, Aaron D; Prohaska, Steffen; Jefferis, Gregory S X E

    2016-07-20

    Neural circuit mapping is generating datasets of tens of thousands of labeled neurons. New computational tools are needed to search and organize these data. We present NBLAST, a sensitive and rapid algorithm, for measuring pairwise neuronal similarity. NBLAST considers both position and local geometry, decomposing neurons into short segments; matched segments are scored using a probabilistic scoring matrix defined by statistics of matches and non-matches. We validated NBLAST on a published dataset of 16,129 single Drosophila neurons. NBLAST can distinguish neuronal types down to the finest level (single identified neurons) without a priori information. Cluster analysis of extensively studied neuronal classes identified new types and unreported topographical features. Fully automated clustering organized the validation dataset into 1,052 clusters, many of which map onto previously described neuronal types. NBLAST supports additional query types, including searching neurons against transgene expression patterns. Finally, we show that NBLAST is effective with data from other invertebrates and zebrafish. VIDEO ABSTRACT. Copyright © 2016 MRC Laboratory of Molecular Biology. Published by Elsevier Inc. All rights reserved.

  16. The effects of specified chemical meals on food intake.

    Science.gov (United States)

    Koopmans, H S; Maggio, C A

    1978-10-01

    Rats received intragastric infusions of various specified chemical meals and were subsequently tested for a reduction in food intake. A second experiment, using a novel technique, tested for conditioned aversion to the meal infusions. The nonnutritive substances, kaolin clay and emulsified fluorocarbon, had no significant effect on food intake. Infusions of 1 M glucose and 1 M sorbitol reduced feeding behavior, but the 1 M sorbitol infusion also produced a conditioned aversion to flavored pellets paired with the sorbitol infusion, showing that the reduced feeding could have been caused by discomfort. Infusion of a high-fat meal consisting of emulsified triolein mixed with small amounts of sugar and protein or the rat's normal liquid diet, Nutrament, also reduced food intake, and both infusions failed to produce a conditioned aversion. The use of specified meals to understand the chemical basis of satiety requires a sensitive behavioral test to establish that the meal does not cause discomfort or other nonspecific effects.

  17. Functionalizing Ascl1 with Novel Intracellular Protein Delivery Technology for Promoting Neuronal Differentiation of Human Induced Pluripotent Stem Cells.

    Science.gov (United States)

    Robinson, Meghan; Chapani, Parv; Styan, Tara; Vaidyanathan, Ranjani; Willerth, Stephanie Michelle

    2016-08-01

    Pluripotent stem cells can become any cell type found in the body. Accordingly, one of the major challenges when working with pluripotent stem cells is producing a highly homogenous population of differentiated cells, which can then be used for downstream applications such as cell therapies or drug screening. The transcription factor Ascl1 plays a key role in neural development and previous work has shown that Ascl1 overexpression using viral vectors can reprogram fibroblasts directly into neurons. Here we report on how a recombinant version of the Ascl1 protein functionalized with intracellular protein delivery technology (Ascl1-IPTD) can be used to rapidly differentiate human induced pluripotent stem cells (hiPSCs) into neurons. We first evaluated a range of Ascl1-IPTD concentrations to determine the most effective amount for generating neurons from hiPSCs cultured in serum free media. Next, we looked at the frequency of Ascl1-IPTD supplementation in the media on differentiation and found that one time supplementation is sufficient enough to trigger the neural differentiation process. Ascl1-IPTD was efficiently taken up by the hiPSCs and enabled rapid differentiation into TUJ1-positive and NeuN-positive populations with neuronal morphology after 8 days. After 12 days of culture, hiPSC-derived neurons produced by Ascl1-IPTD treatment exhibited greater neurite length and higher numbers of branch points compared to neurons derived using a standard neural progenitor differentiation protocol. This work validates Ascl1-IPTD as a powerful tool for engineering neural tissue from pluripotent stem cells.

  18. Successive neuron loss in the thalamus and cortex in a mouse model of infantile neuronal ceroid lipofuscinosis.

    Science.gov (United States)

    Kielar, Catherine; Maddox, Lucy; Bible, Ellen; Pontikis, Charlie C; Macauley, Shannon L; Griffey, Megan A; Wong, Michael; Sands, Mark S; Cooper, Jonathan D

    2007-01-01

    Infantile neuronal ceroid lipofuscinosis (INCL) is caused by deficiency of the lysosomal enzyme, palmitoyl protein thioesterase 1 (PPT1). We have investigated the onset and progression of pathological changes in Ppt1 deficient mice (Ppt1-/-) and the development of their seizure phenotype. Surprisingly, cortical atrophy and neuron loss occurred only late in disease progression but were preceded by localized astrocytosis within individual thalamic nuclei and the progressive loss of thalamic neurons that relay different sensory modalities to the cortex. This thalamic neuron loss occurred first within the visual system and only subsequently in auditory and somatosensory relay nuclei or the inhibitory reticular thalamic nucleus. The loss of granule neurons and GABAergic interneurons followed in each corresponding cortical region, before the onset of seizure activity. These findings provide novel evidence for successive neuron loss within the thalamus and cortex in Ppt1-/- mice, revealing the thalamus as an important early focus of INCL pathogenesis.

  19. A role for neuronal cAMP responsive-element binding (CREB)-1 in brain responses to calorie restriction

    Science.gov (United States)

    Fusco, Salvatore; Ripoli, Cristian; Podda, Maria Vittoria; Ranieri, Sofia Chiatamone; Leone, Lucia; Toietta, Gabriele; McBurney, Michael W.; Schütz, Günther; Riccio, Antonella; Grassi, Claudio; Galeotti, Tommaso; Pani, Giovambattista

    2012-01-01

    Calorie restriction delays brain senescence and prevents neurodegeneration, but critical regulators of these beneficial responses other than the NAD+-dependent histone deacetylase Sirtuin-1 (Sirt-1) are unknown. We report that effects of calorie restriction on neuronal plasticity, memory and social behavior are abolished in mice lacking cAMP responsive-element binding (CREB)-1 in the forebrain. Moreover, CREB deficiency drastically reduces the expression of Sirt-1 and the induction of genes relevant to neuronal metabolism and survival in the cortex and hippocampus of dietary-restricted animals. Biochemical studies reveal a complex interplay between CREB and Sirt-1: CREB directly regulates the transcription of the sirtuin in neuronal cells by binding to Sirt-1 chromatin; Sirt-1, in turn, is recruited by CREB to DNA and promotes CREB-dependent expression of target gene peroxisome proliferator-activated receptor-γ coactivator-1α and neuronal NO Synthase. Accordingly, expression of these CREB targets is markedly reduced in the brain of Sirt KO mice that are, like CREB-deficient mice, poorly responsive to calorie restriction. Thus, the above circuitry, modulated by nutrient availability, links energy metabolism with neurotrophin signaling, participates in brain adaptation to nutrient restriction, and is potentially relevant to accelerated brain aging by overnutrition and diabetes. PMID:22190495

  20. Neuroprotective effects of ginsenoside Rb1 on high glucose-induced neurotoxicity in primary cultured rat hippocampal neurons.

    Science.gov (United States)

    Liu, Di; Zhang, Hong; Gu, Wenjuan; Liu, Yuqin; Zhang, Mengren

    2013-01-01

    Ginsenoside Rb1 is one of the main active principles in traditional herb ginseng and has been reported to have a wide variety of neuroprotective effects. Endoplasmic reticulum (ER) stress has been implicated in neurodegenerative diseases, so the present study aimed to observe the effects of ginsenoside Rb1 on ER stress signaling pathways in high glucose-treated hippocampal neurons. The results from MTT, TUNEL labeling and Annexin V-FITC/PI/Hoechst assays showed that incubating neurons with 50 mM high glucose for 72 h decreased cell viability and increased the number of apoptotic cells whereas treating neurons with 1 μM Rb1 for 72 h protected the neurons against high glucose-induced cell damage. Further molecular mechanism study demonstrated that Rb1 suppressed the activation of ER stress-associated proteins including protein kinase RNA (PKR)-like ER kinase (PERK) and C/EBP homology protein (CHOP) and downregulation of Bcl-2 induced by high glucose. Moreover, Rb1 inhibited both the elevation of intracellular reactive oxygen species (ROS) and the disruption of mitochondrial membrane potential induced by high glucose. In addition, the high glucose-induced cell apoptosis, activation of ER stress, ROS accumulation and mitochondrial dysfunction can also be attenuated by the inhibitor of ER stress 4-phenylbutyric acid (4-PBA) and anti-oxidant N-acetylcysteine(NAC). In conclusion, these results suggest that Rb1 may protect neurons against high glucose-induced cell injury through inhibiting CHOP signaling pathway as well as oxidative stress and mitochondrial dysfunction.

  1. Fragile X Proteins FMRP and FXR2P Control Synaptic GluA1 Expression and Neuronal Maturation via Distinct Mechanisms

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    Weixiang Guo

    2015-06-01

    Full Text Available Fragile X mental retardation protein (FMRP and its autosomal paralog FXR2P are selective neuronal RNA-binding proteins, and mice that lack either protein exhibit cognitive deficits. Although double-mutant mice display more severe learning deficits than single mutants, the molecular mechanism behind this remains unknown. In the present study, we discovered that FXR2P (also known as FXR2 is important for neuronal dendritic development. FMRP and FXR2P additively promote the maturation of new neurons by regulating a common target, the AMPA receptor GluA1, but they do so via distinct mechanisms: FXR2P binds and stabilizes GluA1 mRNA and enhances subsequent protein expression, whereas FMRP promotes GluA1 membrane delivery. Our findings unveil important roles for FXR2P and GluA1 in neuronal development, uncover a regulatory mechanism of GluA1, and reveal a functional convergence between fragile X proteins in neuronal development.

  2. Amylin and GLP-1 target different populations of area postrema neurons that are both modulated by nutrient stimuli.

    Science.gov (United States)

    Züger, Daniela; Forster, Karoline; Lutz, Thomas A; Riediger, Thomas

    2013-03-15

    The area postrema mediates the hypophagic effect of the pancreatic hormone amylin and is also sensitive to glucagon-like peptide 1 (GLP-1). Protein seems to modulate amylin responsiveness because amylin seems to produce a stronger hypophagic effect and a stronger c-Fos expression when protein is absent from the diet. Accordingly, amylin induces a stronger c-Fos expression in the AP when injected in fasted compared to ad libitum fed rats. Here we tested the hypothesis that diet-derived protein attenuates the amylin dependent suppression of feeding and AP activation using isocaloric diets that differed in their protein content. Moreover, we investigated whether peripheral amino acid injection attenuates amylin-induced c-Fos expression in fasted rats. Since recent evidence suggests that GLP-1 may also reduce eating via the AP we tested whether 24 h fasting also increases neuronal AP responsiveness to GLP-1 similar to the fasting-induced increase in amylin responsiveness. Finally, we used the calcitonin receptor (CTR) as an immunohistochemical marker for amylin-receptive AP neurons to investigate whether amylin's target neurons differ from GLP-1 responsive AP neurons. We also dissociated amylin responsive cells from neurons implicated in other AP-mediated functions such as aversion or blood pressure regulation. For this purpose, we conducted c-Fos/CTR double staining after LiCl or angiotensin II treatment, respectively. Amylin (5 μg/kg s.c.) was more effective to reduce the intake of a 1% vs. an 8% or 18% protein diet and to induce c-Fos expression in the AP in rats receiving 1% vs. 18% protein diet. Increased protein intake was associated with increased blood amino acid levels. Peripheral injection of amino acids (1 g/kg i.p.) attenuated the amylin-induced AP activation in 24 h fasted rats. Similar to amylin, GLP-1 (100 μg/kg i.p.) elicited a significant c-Fos response only in fasted but not in ad libitum fed rats. However, in contrast to a high co-localization of

  3. NeuronMetrics: software for semi-automated processing of cultured neuron images.

    Science.gov (United States)

    Narro, Martha L; Yang, Fan; Kraft, Robert; Wenk, Carola; Efrat, Alon; Restifo, Linda L

    2007-03-23

    Using primary cell culture to screen for changes in neuronal morphology requires specialized analysis software. We developed NeuronMetrics for semi-automated, quantitative analysis of two-dimensional (2D) images of fluorescently labeled cultured neurons. It skeletonizes the neuron image using two complementary image-processing techniques, capturing fine terminal neurites with high fidelity. An algorithm was devised to span wide gaps in the skeleton. NeuronMetrics uses a novel strategy based on geometric features called faces to extract a branch number estimate from complex arbors with numerous neurite-to-neurite contacts, without creating a precise, contact-free representation of the neurite arbor. It estimates total neurite length, branch number, primary neurite number, territory (the area of the convex polygon bounding the skeleton and cell body), and Polarity Index (a measure of neuronal polarity). These parameters provide fundamental information about the size and shape of neurite arbors, which are critical factors for neuronal function. NeuronMetrics streamlines optional manual tasks such as removing noise, isolating the largest primary neurite, and correcting length for self-fasciculating neurites. Numeric data are output in a single text file, readily imported into other applications for further analysis. Written as modules for ImageJ, NeuronMetrics provides practical analysis tools that are easy to use and support batch processing. Depending on the need for manual intervention, processing time for a batch of approximately 60 2D images is 1.0-2.5 h, from a folder of images to a table of numeric data. NeuronMetrics' output accelerates the quantitative detection of mutations and chemical compounds that alter neurite morphology in vitro, and will contribute to the use of cultured neurons for drug discovery.

  4. Herpes Simplex Virus Type 1 Infects Enteric Neurons and Triggers Gut Dysfunction via Macrophage Recruitment.

    Science.gov (United States)

    Brun, Paola; Qesari, Marsela; Marconi, Peggy C; Kotsafti, Andromachi; Porzionato, Andrea; Macchi, Veronica; Schwendener, Reto A; Scarpa, Marco; Giron, Maria C; Palù, Giorgio; Calistri, Arianna; Castagliuolo, Ignazio

    2018-01-01

    Herpes Simplex Virus type 1 (HSV-1), a neurotropic pathogen widespread in human population, infects the enteric nervous system (ENS) in humans and rodents and causes intestinal neuromuscular dysfunction in rats. Although infiltration of inflammatory cells in the myenteric plexus and neurodegeneration of enteric nerves are common features of patients suffering from functional intestinal disorders, the proof of a pathogenic link with HSV-1 is still unsettled mainly because the underlying mechanisms are largely unknown. In this study we demonstrated that following intragastrical administration HSV-1 infects neurons within the myenteric plexus resulting in functional and structural alterations of the ENS. By infecting mice with HSV-1 replication-defective strain we revealed that gastrointestinal neuromuscular anomalies were however independent of viral replication. Indeed, enteric neurons exposed to UV-inactivated HSV-1 produced monocyte chemoattractant protein-1 (MCP-1/CCL2) to recruit activated macrophages in the longitudinal muscle myenteric plexus. Infiltrating macrophages produced reactive oxygen and nitrogen species and directly harmed enteric neurons resulting in gastrointestinal dysmotility. In HSV-1 infected mice intestinal neuromuscular dysfunctions were ameliorated by in vivo administration of (i) liposomes containing dichloromethylene bisphosphonic acid (clodronate) to deplete tissue macrophages, (ii) CCR2 chemokine receptor antagonist RS504393 to block the CCL2/CCR2 pathway, (iii) Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) and AR-C 102222 to quench production of nitrogen reactive species produced via iNOS. Overall these data demonstrate that HSV-1 infection makes enteric neurons recruit macrophages via production of a specific chemoattractant factor. The resulting inflammatory reaction is mandatory for intestinal dysmotility. These findings provide insights into the neuro-immune communication that occurs in the ENS following HSV-1 infection

  5. Herpes Simplex Virus Type 1 Infects Enteric Neurons and Triggers Gut Dysfunction via Macrophage Recruitment

    Directory of Open Access Journals (Sweden)

    Paola Brun

    2018-03-01

    Full Text Available Herpes Simplex Virus type 1 (HSV-1, a neurotropic pathogen widespread in human population, infects the enteric nervous system (ENS in humans and rodents and causes intestinal neuromuscular dysfunction in rats. Although infiltration of inflammatory cells in the myenteric plexus and neurodegeneration of enteric nerves are common features of patients suffering from functional intestinal disorders, the proof of a pathogenic link with HSV-1 is still unsettled mainly because the underlying mechanisms are largely unknown. In this study we demonstrated that following intragastrical administration HSV-1 infects neurons within the myenteric plexus resulting in functional and structural alterations of the ENS. By infecting mice with HSV-1 replication-defective strain we revealed that gastrointestinal neuromuscular anomalies were however independent of viral replication. Indeed, enteric neurons exposed to UV-inactivated HSV-1 produced monocyte chemoattractant protein-1 (MCP-1/CCL2 to recruit activated macrophages in the longitudinal muscle myenteric plexus. Infiltrating macrophages produced reactive oxygen and nitrogen species and directly harmed enteric neurons resulting in gastrointestinal dysmotility. In HSV-1 infected mice intestinal neuromuscular dysfunctions were ameliorated by in vivo administration of (i liposomes containing dichloromethylene bisphosphonic acid (clodronate to deplete tissue macrophages, (ii CCR2 chemokine receptor antagonist RS504393 to block the CCL2/CCR2 pathway, (iii Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME and AR-C 102222 to quench production of nitrogen reactive species produced via iNOS. Overall these data demonstrate that HSV-1 infection makes enteric neurons recruit macrophages via production of a specific chemoattractant factor. The resulting inflammatory reaction is mandatory for intestinal dysmotility. These findings provide insights into the neuro-immune communication that occurs in the ENS following HSV-1

  6. Direct Reprogramming of Adult Human Somatic Stem Cells Into Functional Neurons Using Sox2, Ascl1, and Neurog2

    Directory of Open Access Journals (Sweden)

    Jessica Alves de Medeiros Araújo

    2018-06-01

    Full Text Available Reprogramming of somatic cells into induced pluripotent stem cells (iPS or directly into cells from a different lineage, including neurons, has revolutionized research in regenerative medicine in recent years. Mesenchymal stem cells are good candidates for lineage reprogramming and autologous transplantation, since they can be easily isolated from accessible sources in adult humans, such as bone marrow and dental tissues. Here, we demonstrate that expression of the transcription factors (TFs SRY (sex determining region Y-box 2 (Sox2, Mammalian achaete-scute homolog 1 (Ascl1, or Neurogenin 2 (Neurog2 is sufficient for reprogramming human umbilical cord mesenchymal stem cells (hUCMSC into induced neurons (iNs. Furthermore, the combination of Sox2/Ascl1 or Sox2/Neurog2 is sufficient to reprogram up to 50% of transfected hUCMSCs into iNs showing electrical properties of mature neurons and establishing synaptic contacts with co-culture primary neurons. Finally, we show evidence supporting the notion that different combinations of TFs (Sox2/Ascl1 and Sox2/Neurog2 may induce multiple and overlapping neuronal phenotypes in lineage-reprogrammed iNs, suggesting that neuronal fate is determined by a combination of signals involving the TFs used for reprogramming but also the internal state of the converted cell. Altogether, the data presented here contribute to the advancement of techniques aiming at obtaining specific neuronal phenotypes from lineage-converted human somatic cells to treat neurological disorders.

  7. CX3CL1-mediated macrophage activation contributed to paclitaxel-induced DRG neuronal apoptosis and painful peripheral neuropathy.

    Science.gov (United States)

    Huang, Zhen-Zhen; Li, Dai; Liu, Cui-Cui; Cui, Yu; Zhu, He-Quan; Zhang, Wen-Wen; Li, Yong-Yong; Xin, Wen-Jun

    2014-08-01

    Painful peripheral neuropathy is a dose-limiting side effect of paclitaxel therapy, which hampers the optimal clinical management of chemotherapy in cancer patients. Currently the underlying mechanisms remain largely unknown. Here we showed that the clinically relevant dose of paclitaxel (3×8mg/kg, cumulative dose 24mg/kg) induced significant upregulation of the chemokine CX3CL1 in the A-fiber primary sensory neurons in vivo and in vitro and infiltration of macrophages into the dorsal root ganglion (DRG) in rats. Paclitaxel treatment also increased cleaved caspase-3 expression, induced the loss of primary afferent terminal fibers and decreased sciatic-evoked A-fiber responses in the spinal dorsal horn, indicating DRG neuronal apoptosis induced by paclitaxel. In addition, the paclitaxel-induced DRG neuronal apoptosis occurred exclusively in the presence of macrophage in vitro study. Intrathecal or systemic injection of CX3CL1 neutralizing antibody blocked paclitaxel-induced macrophage recruitment and neuronal apoptosis in the DRG, and also attenuated paclitaxel-induced allodynia. Furthermore, depletion of macrophage by systemic administration of clodronate inhibited paclitaxel-induced allodynia. Blocking CX3CL1 decreased activation of p38 MAPK in the macrophage, and inhibition of p38 MAPK activity blocked the neuronal apoptosis and development of mechanical allodynia induced by paclitaxel. These findings provide novel evidence that CX3CL1-recruited macrophage contributed to paclitaxel-induced DRG neuronal apoptosis and painful peripheral neuropathy. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. NeuronBank: a tool for cataloging neuronal circuitry

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    Paul S Katz

    2010-04-01

    Full Text Available The basic unit of any nervous system is the neuron. Therefore, understanding the operation of nervous systems ultimately requires an inventory of their constituent neurons and synaptic connectivity, which form neural circuits. The presence of uniquely identifiable neurons or classes of neurons in many invertebrates has facilitated the construction of cellular-level connectivity diagrams that can be generalized across individuals within a species. Homologous neurons can also be recognized across species. Here we describe NeuronBank.org, a web-based tool that we are developing for cataloging, searching, and analyzing neuronal circuitry within and across species. Information from a single species is represented in an individual branch of NeuronBank. Users can search within a branch or perform queries across branches to look for similarities in neuronal circuits across species. The branches allow for an extensible ontology so that additional characteristics can be added as knowledge grows. Each entry in NeuronBank generates a unique accession ID, allowing it to be easily cited. There is also an automatic link to a Wiki page allowing an encyclopedic explanation of the entry. All of the 44 previously published neurons plus one previously unpublished neuron from the mollusc, Tritonia diomedea, have been entered into a branch of NeuronBank as have 4 previously published neurons from the mollusc, Melibe leonina. The ability to organize information about neuronal circuits will make this information more accessible, ultimately aiding research on these important models.

  9. Phospholipase D1 increases Bcl-2 expression during neuronal differentiation of rat neural stem cells.

    Science.gov (United States)

    Park, Shin-Young; Ma, Weina; Yoon, Sung Nyo; Kang, Min Jeong; Han, Joong-Soo

    2015-01-01

    We studied the possible role of phospholipase D1 (PLD1) in the neuronal differentiation, including neurite formation of neural stem cells. PLD1 protein and PLD activity increased during neuronal differentiation. Bcl-2 also increased. Downregulation of PLD1 by transfection with PLD1 siRNA or a dominant-negative form of PLD1 (DN-PLD1) inhibited both neurite outgrowth and Bcl-2 expression. PLD activity was dramatically reduced by a PLCγ (phospholipase Cγ) inhibitor (U73122), a Ca(2+)chelator (BAPTA-AM), and a PKCα (protein kinase Cα) inhibitor (RO320432). Furthermore, treatment with arachidonic acid (AA) which is generated by the action of PLA2 (phospholipase A2) on phosphatidic acid (a PLD1 product), increased the phosphorylation of p38 MAPK and CREB, as well as Bcl-2 expression, indicating that PLA2 is involved in the differentiation process resulting from PLD1 activation. PGE2 (prostaglandin E2), a cyclooxygenase product of AA, also increased during neuronal differentiation. Moreover, treatment with PGE2 increased the phosphorylation of p38 MAPK and CREB, as well as Bcl-2 expression, and this effect was inhibited by a PKA inhibitor (Rp-cAMP). As expected, inhibition of p38 MAPK resulted in loss of CREB activity, and when CREB activity was blocked with CREB siRNA, Bcl-2 production also decreased. We also showed that the EP4 receptor was required for the PKA/p38MAPK/CREB/Bcl-2 pathway. Taken together, these observations indicate that PLD1 is activated by PLCγ/PKCα signaling and stimulate Bcl-2 expression through PLA2/Cox2/EP4/PKA/p38MAPK/CREB during neuronal differentiation of rat neural stem cells.

  10. On the number of preganglionic neurones driving human postganglionic sympathetic neurones: a comparison of modelling and empirical data

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    Vaughan G Macefield

    2011-12-01

    Full Text Available Postganglionic sympathetic axons in awake healthy human subjects, regardless of their identity as muscle vasoconstrictor, cutaneous vasoconstrictor or sudomotor neurones, discharge with a low firing probability (~30%, generate low firing rates (~0.5 Hz and typically fire only once per cardiac interval. The purpose of the present study was to use modelling of spike trains in an attempt to define the number of preganglionic neurones that drive an individual postganglionic neurone. Artificial spike trains were generated in 1-3 preganglionic neurones converging onto a single postganglionic neurone. Each preganglionic input fired with a mean interval distribution of either 1000, 1500, 2000, 2500 or 3000 ms and the standard deviation varied between 0.5, 1.0 and 2.0 x the mean interval; the discharge frequency of each preganglionic neurone exhibited positive skewness and kurtosis. Of the 45 patterns examined, the mean discharge properties of the postganglionic neurone could only be explained by it being driven by, on average, two preganglionic neurones firing with a mean interspike interval of 2500 ms and SD of 5000 ms. The mean firing rate resulting from this pattern was 0.22 Hz, comparable to that of spontaneously active muscle vasoconstrictor neurones in healthy subjects (0.40 Hz. Likewise, the distribution of the number of spikes per cardiac interval was similar between the modelled and actual data: 0 spikes (69.5 vs 66.6 %, 1 spike (25.6 vs 21.2 %, 2 spikes (4.3 vs 6.4 %, 3 spikes (0.5 vs 1.7 % and 4 spikes (0.1 vs 0.7 %. Although some features of the firing patterns could be explained by the postganglionic neurone being driven by a single preganglionic neurone, none of the emulated firing patterns generated by the firing of three preganglionic neurones matched the discharge of the real neurones. These modelling data indicate that, on average, human postganglionic sympathetic neurones are driven by two preganglionic inputs.

  11. Metabolomic profiling reveals a role for CPT1c in neuronal oxidative metabolism.

    Science.gov (United States)

    Lee, Jieun; Wolfgang, Michael J

    2012-10-25

    Carnitine Palmitoyltransferase-1c (CPT1c) is a neuron specific homologue of the carnitine acyltransferase family of enzymes. CPT1 isoenzymes transfer long chain acyl groups to carnitine. This constitutes a rate setting step for mitochondrial fatty acid beta-oxidation by facilitating the initial step in acyl transfer to the mitochondrial matrix. In general, neurons do not heavily utilize fatty acids for bioenergetic needs and definitive enzymatic activity has been unable to be demonstrated for CPT1c. Although there are studies suggesting an enzymatic role of CPT1c, its role in neurochemistry remains elusive. In order to better understand how CPT1c functions in neural metabolism, we performed unbiased metabolomic profiling on wild-type (WT) and CPT1c knockout (KO) mouse brains. Consistent with the notion that CPT1c is not involved in fatty acid beta-oxidation, there were no changes in metabolites associated with fatty acid oxidation. Endocannabinoids were suppressed in the CPT1c KO, which may explain the suppression of food intake seen in CPT1c KO mice. Although products of beta-oxidation were unchanged, small changes in carnitine and carnitine metabolites were observed. Finally, we observed changes in redox homeostasis including a greater than 2-fold increase in oxidized glutathione. This indicates that CPT1c may play a role in neural oxidative metabolism. Steady-state metabolomic analysis of CPT1c WT and KO mouse brains identified a small number of metabolites that differed between CPT1c WT and KO mice. The subtle changes in a broad range of metabolites in vivo indicate that CPT1c does not play a significant or required role in fatty acid oxidation; however, it could play an alternative role in neuronal oxidative metabolism.

  12. Metabolomic profiling reveals a role for CPT1c in neuronal oxidative metabolism

    Directory of Open Access Journals (Sweden)

    Lee Jieun

    2012-10-01

    Full Text Available Abstract Background Carnitine Palmitoyltransferase-1c (CPT1c is a neuron specific homologue of the carnitine acyltransferase family of enzymes. CPT1 isoenzymes transfer long chain acyl groups to carnitine. This constitutes a rate setting step for mitochondrial fatty acid beta-oxidation by facilitating the initial step in acyl transfer to the mitochondrial matrix. In general, neurons do not heavily utilize fatty acids for bioenergetic needs and definitive enzymatic activity has been unable to be demonstrated for CPT1c. Although there are studies suggesting an enzymatic role of CPT1c, its role in neurochemistry remains elusive. Results In order to better understand how CPT1c functions in neural metabolism, we performed unbiased metabolomic profiling on wild-type (WT and CPT1c knockout (KO mouse brains. Consistent with the notion that CPT1c is not involved in fatty acid beta-oxidation, there were no changes in metabolites associated with fatty acid oxidation. Endocannabinoids were suppressed in the CPT1c KO, which may explain the suppression of food intake seen in CPT1c KO mice. Although products of beta-oxidation were unchanged, small changes in carnitine and carnitine metabolites were observed. Finally, we observed changes in redox homeostasis including a greater than 2-fold increase in oxidized glutathione. This indicates that CPT1c may play a role in neural oxidative metabolism. Conclusions Steady-state metabolomic analysis of CPT1c WT and KO mouse brains identified a small number of metabolites that differed between CPT1c WT and KO mice. The subtle changes in a broad range of metabolites in vivo indicate that CPT1c does not play a significant or required role in fatty acid oxidation; however, it could play an alternative role in neuronal oxidative metabolism.

  13. Distinct populations of GABAergic neurons in mouse rhombomere 1 express but do not require the homeodomain transcription factor PITX2.

    Science.gov (United States)

    Waite, Mindy R; Skaggs, Kaia; Kaviany, Parisa; Skidmore, Jennifer M; Causeret, Frédéric; Martin, James F; Martin, Donna M

    2012-01-01

    Hindbrain rhombomere 1 (r1) is located caudal to the isthmus, a critical organizer region, and rostral to rhombomere 2 in the developing mouse brain. Dorsal r1 gives rise to the cerebellum, locus coeruleus, and several brainstem nuclei, whereas cells from ventral r1 contribute to the trochlear and trigeminal nuclei as well as serotonergic and GABAergic neurons of the dorsal raphe. Recent studies have identified several molecular events controlling dorsal r1 development. In contrast, very little is known about ventral r1 gene expression and the genetic mechanisms regulating its formation. Neurons with distinct neurotransmitter phenotypes have been identified in ventral r1 including GABAergic, serotonergic, and cholinergic neurons. Here we show that PITX2 marks a distinct population of GABAergic neurons in mouse embryonic ventral r1. This population appears to retain its GABAergic identity even in the absence of PITX2. We provide a comprehensive map of markers that places these PITX2-positive GABAergic neurons in a region of r1 that intersects and is potentially in communication with the dorsal raphe. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. The L444P Gba1 mutation enhances alpha-synuclein induced loss of nigral dopaminergic neurons in mice

    Science.gov (United States)

    Migdalska-Richards, Anna; Wegrzynowicz, Michal; Rusconi, Raffaella; Deangeli, Giulio; Di Monte, Donato A; Spillantini, Maria G; Schapira, Anthony H V

    2017-01-01

    Abstract Mutations in glucocerebrosidase 1 (GBA1) represent the most prevalent risk factor for Parkinson’s disease. The molecular mechanisms underlying the link between GBA1 mutations and Parkinson’s disease are incompletely understood. We analysed two aged (24-month-old) Gba1 mouse models, one carrying a knock-out mutation and the other a L444P knock-in mutation. A significant reduction of glucocerebrosidase activity was associated with increased total alpha-synuclein accumulation in both these models. Gba1 mutations alone did not alter the number of nigral dopaminergic neurons nor striatal dopamine levels. We then investigated the effect of overexpression of human alpha-synuclein in the substantia nigra of aged (18 to 21-month-old) L444P Gba1 mice. Following intraparenchymal injections of human alpha-synuclein carrying viral vectors, pathological accumulation of phosphorylated alpha-synuclein occurred within the transduced neurons. Stereological counts of nigral dopaminergic neurons revealed a significantly greater cell loss in Gba1-mutant than wild-type mice. These results indicate that Gba1 deficiency enhances neuronal vulnerability to neurodegenerative processes triggered by increased alpha-synuclein expression. PMID:28969384

  15. Segregated populations of hippocampal principal CA1 neurons mediating conditioning and extinction of contextual fear.

    Science.gov (United States)

    Tronson, Natalie C; Schrick, Christina; Guzman, Yomayra F; Huh, Kyu Hwan; Srivastava, Deepak P; Penzes, Peter; Guedea, Anita L; Gao, Can; Radulovic, Jelena

    2009-03-18

    Learning processes mediating conditioning and extinction of contextual fear require activation of several key signaling pathways in the hippocampus. Principal hippocampal CA1 neurons respond to fear conditioning by a coordinated activation of multiple protein kinases and immediate early genes, such as cFos, enabling rapid and lasting consolidation of contextual fear memory. The extracellular signal-regulated kinase (Erk) additionally acts as a central mediator of fear extinction. It is not known however, whether these molecular events take place in overlapping or nonoverlapping neuronal populations. By using mouse models of conditioning and extinction of fear, we set out to determine the time course of cFos and Erk activity, their cellular overlap, and regulation by afferent cholinergic input from the medial septum. Analyses of cFos(+) and pErk(+) cells by immunofluorescence revealed predominant nuclear activation of either protein during conditioning and extinction of fear, respectively. Transgenic cFos-LacZ mice were further used to label in vivo Fos(+) hippocampal cells during conditioning followed by pErk immunostaining after extinction. The results showed that these signaling molecules were activated in segregated populations of hippocampal principal neurons. Furthermore, immunotoxin-induced lesions of medial septal neurons, providing cholinergic input into the hippocampus, selectively abolished Erk activation and extinction of fear without affecting cFos responses and conditioning. These results demonstrate that extinction mechanisms based on Erk signaling involve a specific population of CA1 principal neurons distinctively regulated by afferent cholinergic input from the medial septum.

  16. Visualization of Sensory Neurons and Their Projections in an Upper Motor Neuron Reporter Line.

    Science.gov (United States)

    Genç, Barış; Lagrimas, Amiko Krisa Bunag; Kuru, Pınar; Hess, Robert; Tu, Michael William; Menichella, Daniela Maria; Miller, Richard J; Paller, Amy S; Özdinler, P Hande

    2015-01-01

    Visualization of peripheral nervous system axons and cell bodies is important to understand their development, target recognition, and integration into complex circuitries. Numerous studies have used protein gene product (PGP) 9.5 [a.k.a. ubiquitin carboxy-terminal hydrolase L1 (UCHL1)] expression as a marker to label sensory neurons and their axons. Enhanced green fluorescent protein (eGFP) expression, under the control of UCHL1 promoter, is stable and long lasting in the UCHL1-eGFP reporter line. In addition to the genetic labeling of corticospinal motor neurons in the motor cortex and degeneration-resistant spinal motor neurons in the spinal cord, here we report that neurons of the peripheral nervous system are also fluorescently labeled in the UCHL1-eGFP reporter line. eGFP expression is turned on at embryonic ages and lasts through adulthood, allowing detailed studies of cell bodies, axons and target innervation patterns of all sensory neurons in vivo. In addition, visualization of both the sensory and the motor neurons in the same animal offers many advantages. In this report, we used UCHL1-eGFP reporter line in two different disease paradigms: diabetes and motor neuron disease. eGFP expression in sensory axons helped determine changes in epidermal nerve fiber density in a high-fat diet induced diabetes model. Our findings corroborate previous studies, and suggest that more than five months is required for significant skin denervation. Crossing UCHL1-eGFP with hSOD1G93A mice generated hSOD1G93A-UeGFP reporter line of amyotrophic lateral sclerosis, and revealed sensory nervous system defects, especially towards disease end-stage. Our studies not only emphasize the complexity of the disease in ALS, but also reveal that UCHL1-eGFP reporter line would be a valuable tool to visualize and study various aspects of sensory nervous system development and degeneration in the context of numerous diseases.

  17. Oligomeric forms of the metastasis-related Mts1 (S100A4) protein stimulate neuronal differentiation in cultures of rat hippocampal neurons

    DEFF Research Database (Denmark)

    Novitskaya, V; Grigorian, M; Kriajevska, M

    2000-01-01

    protein family. The oligomeric but not the dimeric form of Mts1 strongly induces differentiation of cultured hippocampal neurons. A mutant with a single Y75F amino acid substitution, which stabilizes the dimeric form of Mts1, is unable to promote neurite extension. Disulfide bonds do not play an essential...

  18. Exercise preconditioning exhibits neuroprotective effects on hippocampal CA1 neuronal damage after cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Nabi Shamsaei; Mehdi Khaksari; Sohaila Erfani; Hamid Rajabi; Nahid Aboutaleb

    2015-01-01

    Recent evidence has suggested the neuroprotective effects of physical exercise on cerebral isch-emic injury. However, the role of physical exercise in cerebral ischemia-induced hippocampal damage remains controversial. The aim of the present study was to evaluate the effects of pre-ischemia treadmill training on hippocampal CA1 neuronal damage after cerebral ischemia. Male adult rats were randomly divided into control, ischemia and exercise + ischemia groups. In the exercise + ischemia group, rats were subjected to running on a treadmill in a designated time schedule (5 days per week for 4 weeks). Then rats underwent cerebral ischemia induction th rough occlusion of common carotids followed by reperfusion. At 4 days after cerebral ischemia, rat learning and memory abilities were evaluated using passive avoidance memory test and rat hippocampal neuronal damage was detected using Nissl and TUNEL staining. Pre-ischemic ex-ercise signiifcantly reduced the number of TUNEL-positive cells and necrotic cell death in the hippocampal CA1 region as compared to the ischemia group. Moreover, pre-ischemic exercise significantly prevented ischemia-induced memory dysfunction. Pre-ischemic exercise mighct prevent memory deficits after cerebral ischemia through rescuing hippocampal CA1 neurons from ischemia-induced degeneration.

  19. Genetic evidence for involvement of neuronally expressed S1P₁ receptor in nociceptor sensitization and inflammatory pain.

    Directory of Open Access Journals (Sweden)

    Norbert Mair

    2011-02-01

    Full Text Available Sphingosine-1-phosphate (S1P is a key regulator of immune response. Immune cells, epithelia and blood cells generate high levels of S1P in inflamed tissue. However, it is not known if S1P acts on the endings of nociceptive neurons, thereby contributing to the generation of inflammatory pain. We found that the S1P₁ receptor for S1P is expressed in subpopulations of sensory neurons including nociceptors. Both S1P and agonists at the S1P₁ receptor induced hypersensitivity to noxious thermal stimulation in vitro and in vivo. S1P-induced hypersensitivity was strongly attenuated in mice lacking TRPV1 channels. S1P and inflammation-induced hypersensitivity was significantly reduced in mice with a conditional nociceptor-specific deletion of the S1P₁ receptor. Our data show that neuronally expressed S1P₁ receptors play a significant role in regulating nociceptor function and that S1P/S1P₁ signaling may be a key player in the onset of thermal hypersensitivity and hyperalgesia associated with inflammation.

  20. DNMT1 mutations found in HSANIE patients affect interaction with UHRF1 and neuronal differentiation.

    Science.gov (United States)

    Smets, Martha; Link, Stephanie; Wolf, Patricia; Schneider, Katrin; Solis, Veronica; Ryan, Joel; Meilinger, Daniela; Qin, Weihua; Leonhardt, Heinrich

    2017-04-15

    DNMT1 is recruited to substrate sites by PCNA and UHRF1 to maintain DNA methylation after replication. The cell cycle dependent recruitment of DNMT1 is mediated by the PCNA-binding domain (PBD) and the targeting sequence (TS) within the N-terminal regulatory domain. The TS domain was found to be mutated in patients suffering from hereditary sensory and autonomic neuropathies with dementia and hearing loss (HSANIE) and autosomal dominant cerebellar ataxia deafness and narcolepsy (ADCA-DN) and is associated with global hypomethylation and site specific hypermethylation. With functional complementation assays in mouse embryonic stem cells, we showed that DNMT1 mutations P496Y and Y500C identified in HSANIE patients not only impair DNMT1 heterochromatin association, but also UHRF1 interaction resulting in hypomethylation. Similar DNA methylation defects were observed when DNMT1 interacting domains in UHRF1, the UBL and the SRA domain, were deleted. With cell-based assays, we could show that HSANIE associated mutations perturb DNMT1 heterochromatin association and catalytic complex formation at methylation sites and decrease protein stability in late S and G2 phase. To investigate the neuronal phenotype of HSANIE mutations, we performed DNMT1 rescue assays and could show that cells expressing mutated DNMT1 were prone to apoptosis and failed to differentiate into neuronal lineage. Our results provide insights into the molecular basis of DNMT1 dysfunction in HSANIE patients and emphasize the importance of the TS domain in the regulation of DNA methylation in pluripotent and differentiating cells. © The Author 2017. Published by Oxford University Press.

  1. How neurons migrate: a dynamic in-silico model of neuronal migration in the developing cortex

    LENUS (Irish Health Repository)

    Setty, Yaki

    2011-09-30

    Abstract Background Neuronal migration, the process by which neurons migrate from their place of origin to their final position in the brain, is a central process for normal brain development and function. Advances in experimental techniques have revealed much about many of the molecular components involved in this process. Notwithstanding these advances, how the molecular machinery works together to govern the migration process has yet to be fully understood. Here we present a computational model of neuronal migration, in which four key molecular entities, Lis1, DCX, Reelin and GABA, form a molecular program that mediates the migration process. Results The model simulated the dynamic migration process, consistent with in-vivo observations of morphological, cellular and population-level phenomena. Specifically, the model reproduced migration phases, cellular dynamics and population distributions that concur with experimental observations in normal neuronal development. We tested the model under reduced activity of Lis1 and DCX and found an aberrant development similar to observations in Lis1 and DCX silencing expression experiments. Analysis of the model gave rise to unforeseen insights that could guide future experimental study. Specifically: (1) the model revealed the possibility that under conditions of Lis1 reduced expression, neurons experience an oscillatory neuron-glial association prior to the multipolar stage; and (2) we hypothesized that observed morphology variations in rats and mice may be explained by a single difference in the way that Lis1 and DCX stimulate bipolar motility. From this we make the following predictions: (1) under reduced Lis1 and enhanced DCX expression, we predict a reduced bipolar migration in rats, and (2) under enhanced DCX expression in mice we predict a normal or a higher bipolar migration. Conclusions We present here a system-wide computational model of neuronal migration that integrates theory and data within a precise

  2. How neurons migrate: a dynamic in-silico model of neuronal migration in the developing cortex

    Directory of Open Access Journals (Sweden)

    Skoblov Nikita

    2011-09-01

    Full Text Available Abstract Background Neuronal migration, the process by which neurons migrate from their place of origin to their final position in the brain, is a central process for normal brain development and function. Advances in experimental techniques have revealed much about many of the molecular components involved in this process. Notwithstanding these advances, how the molecular machinery works together to govern the migration process has yet to be fully understood. Here we present a computational model of neuronal migration, in which four key molecular entities, Lis1, DCX, Reelin and GABA, form a molecular program that mediates the migration process. Results The model simulated the dynamic migration process, consistent with in-vivo observations of morphological, cellular and population-level phenomena. Specifically, the model reproduced migration phases, cellular dynamics and population distributions that concur with experimental observations in normal neuronal development. We tested the model under reduced activity of Lis1 and DCX and found an aberrant development similar to observations in Lis1 and DCX silencing expression experiments. Analysis of the model gave rise to unforeseen insights that could guide future experimental study. Specifically: (1 the model revealed the possibility that under conditions of Lis1 reduced expression, neurons experience an oscillatory neuron-glial association prior to the multipolar stage; and (2 we hypothesized that observed morphology variations in rats and mice may be explained by a single difference in the way that Lis1 and DCX stimulate bipolar motility. From this we make the following predictions: (1 under reduced Lis1 and enhanced DCX expression, we predict a reduced bipolar migration in rats, and (2 under enhanced DCX expression in mice we predict a normal or a higher bipolar migration. Conclusions We present here a system-wide computational model of neuronal migration that integrates theory and data within a

  3. Transduced human copper chaperone for Cu,Zn-SOD (PEP-1-CCS) protects against neuronal cell death.

    Science.gov (United States)

    Choi, Soo Hyun; Kim, Dae Won; Kim, So Young; An, Jae Jin; Lee, Sun Hwa; Choi, Hee Soon; Sohn, Eun Jung; Hwang, Seok-Il; Won, Moo Ho; Kang, Tae-Cheon; Kwon, Hyung Joo; Kang, Jung Hoon; Cho, Sung-Woo; Park, Jinseu; Eum, Won Sik; Choi, Soo Young

    2005-12-31

    Reactive oxygen species (ROS) contribute to the development of various human diseases. Cu,Zn-superoxide dismutase (SOD) is one of the major means by which cells counteract the deleterious effects of ROS. SOD activity is dependent upon bound copper ions supplied by its partner metallochaperone protein, copper chaperone for SOD (CCS). In the present study, we investigated the protective effects of PEP-1-CCS against neuronal cell death and ischemic insults. When PEP-1-CCS was added to the culture medium of neuronal cells, it rapidly entered the cells and protected them against paraquat-induced cell death. Moreover, transduced PEP-1-CCS markedly increased endogenous SOD activity in the cells. Immunohistochemical analysis revealed that it prevented neuronal cell death in the hippocampus in response to transient forebrain ischemia. These results suggest that CCS is essential to activate SOD, and that transduction of PEP-1-CCS provides a potential strategy for therapeutic delivery in various human diseases including stroke related to SOD or ROS.

  4. Rescuing effects of RXR agonist bexarotene on aging-related synapse loss depend on neuronal LRP1.

    Science.gov (United States)

    Tachibana, Masaya; Shinohara, Mitsuru; Yamazaki, Yu; Liu, Chia-Chen; Rogers, Justin; Bu, Guojun; Kanekiyo, Takahisa

    2016-03-01

    Apolipoprotein E (apoE) plays a critical role in maintaining synaptic integrity by transporting cholesterol to neurons through the low-density lipoprotein receptor related protein-1 (LRP1). Bexarotene, a retinoid X receptor (RXR) agonist, has been reported to have potential beneficial effects on cognition by increasing brain apoE levels and lipidation. To investigate the effects of bexarotene on aging-related synapse loss and the contribution of neuronal LRP1 to the pathway, forebrain neuron-specific LRP1 knockout (nLrp1(-/-)) and littermate control mice were administered with bexarotene-formulated diet (100mg/kg/day) or control diet at the age of 20-24 months for 8 weeks. Upon bexarotene treatment, levels of brain apoE and ATP-binding cassette sub-family A member 1 (ABCA1) were significantly increased in both mice. While levels of PSD95, glutamate receptor 1 (GluR1), and N-methyl-d-aspartate receptor NR1 subunit (NR1), which are key postsynaptic proteins that regulate synaptic plasticity, were decreased with aging, they were restored by bexarotene treatment in the brains of control but not nLrp1(-/-) mice. These results indicate that the beneficial effects of bexarotene on synaptic integrity depend on the presence of neuronal LRP1. However, we also found that bexarotene treatment led to the activation of glial cells, weight loss and hepatomegaly, which are likely due to hepatic failure. Taken together, our results demonstrate that apoE-targeted treatment through the RXR pathway has a potential beneficial effect on synapses during aging; however, the therapeutic application of bexarotene requires extreme caution due to its toxic side effects. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Brain-specific Foxp1 deletion impairs neuronal development and causes autistic-like behaviour.

    Science.gov (United States)

    Bacon, C; Schneider, M; Le Magueresse, C; Froehlich, H; Sticht, C; Gluch, C; Monyer, H; Rappold, G A

    2015-05-01

    Neurodevelopmental disorders are multi-faceted and can lead to intellectual disability, autism spectrum disorder and language impairment. Mutations in the Forkhead box FOXP1 gene have been linked to all these disorders, suggesting that it may play a central role in various cognitive and social processes. To understand the role of Foxp1 in the context of neurodevelopment leading to alterations in cognition and behaviour, we generated mice with a brain-specific Foxp1 deletion (Nestin-Cre(Foxp1-/-)mice). The mutant mice were viable and allowed for the first time the analysis of pre- and postnatal neurodevelopmental phenotypes, which included a pronounced disruption of the developing striatum and more subtle alterations in the hippocampus. More detailed analysis in the CA1 region revealed abnormal neuronal morphogenesis that was associated with reduced excitability and an imbalance of excitatory to inhibitory input in CA1 hippocampal neurons in Nestin-Cre(Foxp1-/-) mice. Foxp1 ablation was also associated with various cognitive and social deficits, providing new insights into its behavioural importance.

  6. The Role of Kiss1 Neurons As Integrators of Endocrine, Metabolic, and Environmental Factors in the Hypothalamic–Pituitary–Gonadal Axis

    Directory of Open Access Journals (Sweden)

    Shel-Hwa Yeo

    2018-04-01

    Full Text Available Kisspeptin–GPR54 signaling in the hypothalamus is required for reproduction and fertility in mammals. Kiss1 neurons are key regulators of gonadotropin-releasing hormone (GnRH release and modulation of the hypothalamic–pituitary–gonadal (HPG axis. Arcuate Kiss1 neurons project to GnRH nerve terminals in the median eminence, orchestrating the pulsatile secretion of luteinizing hormone (LH through the intricate interaction between GnRH pulse frequency and the pituitary gonadotrophs. Arcuate Kiss1 neurons, also known as KNDy neurons in rodents and ruminants because of their co-expression of neurokinin B and dynorphin represent an ideal hub to receive afferent inputs from other brain regions in response to physiological and environmental changes, which can regulate the HPG axis. This review will focus on studies performed primarily in rodent and ruminant species to explore potential afferent inputs to Kiss1 neurons with emphasis on the arcuate region but also considering the rostral periventricular region of the third ventricle (RP3V. Specifically, we will discuss how these inputs can be modulated by hormonal, metabolic, and environmental factors to control gonadotropin secretion and fertility. We also summarize the methods and techniques that can be used to study functional inputs into Kiss1 neurons.

  7. Tet1 oxidase regulates neuronal gene transcription, active DNA hydroxymethylation, object location memory, and threat recognition memory

    Directory of Open Access Journals (Sweden)

    Dinesh Kumar

    2015-10-01

    Full Text Available A dynamic equilibrium between DNA methylation and demethylation of neuronal activity-regulated genes is crucial for memory processes. However, the mechanisms underlying this equilibrium remain elusive. Tet1 oxidase has been shown to play a key role in the active DNA demethylation in the central nervous system. In this study, we used Tet1 gene knockout (Tet1KO mice to examine the involvement of Tet1 in memory consolidation and storage in the adult brain. We found that Tet1 ablation leads to altered expression of numerous neuronal activity-regulated genes, compensatory upregulation of active demethylation pathway genes, and upregulation of various epigenetic modifiers. Moreover, Tet1KO mice showed an enhancement in the consolidation and storage of threat recognition (cued and contextual fear conditioning and object location memories. We conclude that Tet1 plays a critical role in regulating neuronal transcription and in maintaining the epigenetic state of the brain associated with memory consolidation and storage.

  8. Feedforward motor information enhances somatosensory responses and sharpens angular tuning of rat S1 barrel cortex neurons.

    Science.gov (United States)

    Khateb, Mohamed; Schiller, Jackie; Schiller, Yitzhak

    2017-01-06

    The primary vibrissae motor cortex (vM1) is responsible for generating whisking movements. In parallel, vM1 also sends information directly to the sensory barrel cortex (vS1). In this study, we investigated the effects of vM1 activation on processing of vibrissae sensory information in vS1 of the rat. To dissociate the vibrissae sensory-motor loop, we optogenetically activated vM1 and independently passively stimulated principal vibrissae. Optogenetic activation of vM1 supra-linearly amplified the response of vS1 neurons to passive vibrissa stimulation in all cortical layers measured. Maximal amplification occurred when onset of vM1 optogenetic activation preceded vibrissa stimulation by 20 ms. In addition to amplification, vM1 activation also sharpened angular tuning of vS1 neurons in all cortical layers measured. Our findings indicated that in addition to output motor signals, vM1 also sends preparatory signals to vS1 that serve to amplify and sharpen the response of neurons in the barrel cortex to incoming sensory input signals.

  9. Signaling triggered by Thy-1 interaction with ß3 integrin on astrocytes is an essential step towards unraveling neuronal Thy-1 function

    Directory of Open Access Journals (Sweden)

    ANA MARIA AVALOS

    2002-01-01

    Full Text Available Thy-1 is an abundant neuronal glycoprotein in mammals. Despite such prevalence, Thy-1 function remains largely obscure in the absence of a defined ligand. Recently described evidence that Thy-1 interacts with ß3 integrin on astrocytes will be discussed. Thy-1 binding to ß3 integrin triggers tyrosine phosphorylation of focal adhesion proteins in astrocytes, thereby promoting focal adhesion formation, cell attachment and spreading. Thy-1 has been reported to modulate neurite outgrowth by triggering a cellular response in neurons. However, our data indicate that Thy-1 can also initiate signaling events that promote adhesion of adjacent astrocytes to the underlying surface. Preliminary results suggest that morphological changes observed in the actin cytoskeleton of astrocytes as a consequence of Thy-1 binding is mediated by small GTPases from the Rho family. Our findings argue that Thy-1 functions in a bimodal fashion, as a receptor on neuronal cells and as a ligand for ß3 integrin receptor on astrocytes. Since Thy-1 is implicated in the inhibition of neurite outgrowth, signaling events in astrocytes are likely to play an important role in this process

  10. HERC 1 ubiquitin ligase mutation affects neocortical, CA3 hippocampal and spinal cord projection neurons. An ultrastructural study

    Directory of Open Access Journals (Sweden)

    Rocío eRuiz

    2016-04-01

    Full Text Available The spontaneous mutation tambaleante is caused by the Gly483Glu substitution in the highly conserved N terminal RCC1-like domain of the HERC1 protein, which leads to the increase of mutated protein levels responsible for cerebellar Purkinje cell death by autophagy. Until now, Purkinje cells have been the only central nervous neurons reported as being targeted by the mutation, and their degeneration elicits an ataxic syndrome in adult mutant mice. However, the ultrastructural analysis performed here demonstrates that signs of autophagy, such as autophagosomes, lysosomes, and altered mitochondria, are present in neocortical pyramidal, CA3 hippocampal pyramidal, and spinal cord motor neurons. The main difference is that the reduction in the number of neurons affected in the tambaleante mutation in the neocortex, the hippocampus, and the spinal cord is not so evident as the dramatic loss of cerebellar Purkinje cells. Interestingly, signs of autophagy are absent in both interneurons and neuroglia cells. Affected neurons have in common that they are projection neurons which receive strong and varied synaptic inputs, and possess the highest degree of neuronal activity. Therefore, because the integrity of the ubiquitin-proteasome system is essential for protein degradation and, hence, for normal protein turnover, it could be hypothesized that the deleterious effects of the misrouting of these pathways would depend directly on the neuronal activity.

  11. Cre-expressing neurons in visual cortex of Ntsr1-Cre GN220 mice are corticothalamic and are depolarized by acetylcholine.

    Science.gov (United States)

    Sundberg, Sofie Charlotte; Lindström, Sarah Helen; Sanchez, Gonzalo Manuel; Granseth, Björn

    2018-01-01

    The Ntsr1-Cre GN220 mouse expresses Cre-recombinase in corticothalamic (CT) neurons in neocortical layer 6. It is not known if the other major types of pyramidal neurons in this layer also express this enzyme. By electrophysiological recordings in slices and histological analysis of the uptake of retrogradely transported beads we show that Cre-positive neurons are CT and not corticocortical or corticoclaustral types. Furthermore, we show that Ntsr1-Cre-positive cells are immuno-positive for the nuclear transcription factor Forkhead box protein P2 (FoxP2). We conclude that Cre-expression is limited to a specific type of pyramidal neuron: CT. However, it appears as not all CT neurons are Cre-expressing; there are indications that the penetrance of the gene is about 90%. We demonstrate the utility of assigning a specific identity to individual neurons by determining that the CT neurons are potently modulated by acetylcholine acting on both nicotinic and muscarinic acetylcholine receptors. These results corroborate the suggested function of these neurons in regulating the gain of thalamocortical transfer of sensory information depending on attentional demand and state of arousal. © 2017 Wiley Periodicals, Inc.

  12. Difference in transient ischemia-induced neuronal damage and glucose transporter-1 immunoreactivity in the hippocampus between adult and young gerbils

    Directory of Open Access Journals (Sweden)

    Seung Min Park

    2016-05-01

    Full Text Available Objective(s: The alteration of glucose transporters is closely related with the pathogenesis of brain edema. We compared neuronal damage/death in the hippocampus between adult and young gerbils following transient cerebral ischemia/reperfusion and changes of glucose transporter-1(GLUT-1-immunoreactive microvessels in their ischemic hippocampal CA1 region. Materials and Methods: Transient cerebral ischemia was developed by 5-min occlusion of both common carotid arteries. Neuronal damage was examined by cresyl violet staining, NeuN immunohistochemistry and Fluoro-Jade B histofluorescence staining and changes in GLUT-1 expression was carried out by immunohistochemistry. Results: About 90% of pyramidal neurons only in the adult CA1 region were damaged after ischemia/reperfusion; in the young, about 53 % of pyramidal neurons were damaged from 7 days after ischemia/reperfusion. The density of GLUT-1-immunoreactive microvessels was significantly higher in the young sham-group than that in the adult sham-group. In the ischemia-operated-groups, the density of GLUT-1-immunoreactive microvessels was significantly decreased in the adult and young at 1 and 4 days post-ischemia, respectively, thereafter, the density of GLUT-1-immunoreactive microvessels was gradually increased in both groups after ischemia/reperfusion. Conclusion: CA1 pyramidal neurons of the young gerbil were damaged much later than that in the adult and that GLUT-1-immunoreactive microvessels were significantly decreased later in the young. These data indicate that GLUT-1 might differently contribute to neuronal damage according to age after ischemic insults.

  13. Synaptic Circuit Organization of Motor Corticothalamic Neurons

    Science.gov (United States)

    Yamawaki, Naoki

    2015-01-01

    Corticothalamic (CT) neurons in layer 6 constitute a large but enigmatic class of cortical projection neurons. How they are integrated into intracortical and thalamo-cortico-thalamic circuits is incompletely understood, especially outside of sensory cortex. Here, we investigated CT circuits in mouse forelimb motor cortex (M1) using multiple circuit-analysis methods. Stimulating and recording from CT, intratelencephalic (IT), and pyramidal tract (PT) projection neurons, we found strong CT↔ CT and CT↔ IT connections; however, CT→IT connections were limited to IT neurons in layer 6, not 5B. There was strikingly little CT↔ PT excitatory connectivity. Disynaptic inhibition systematically accompanied excitation in these pathways, scaling with the amplitude of excitation according to both presynaptic (class-specific) and postsynaptic (cell-by-cell) factors. In particular, CT neurons evoked proportionally more inhibition relative to excitation (I/E ratio) than IT neurons. Furthermore, the amplitude of inhibition was tuned to match the amount of excitation at the level of individual neurons; in the extreme, neurons receiving no excitation received no inhibition either. Extending these studies to dissect the connectivity between cortex and thalamus, we found that M1-CT neurons and thalamocortical neurons in the ventrolateral (VL) nucleus were remarkably unconnected in either direction. Instead, VL axons in the cortex excited both IT and PT neurons, and CT axons in the thalamus excited other thalamic neurons, including those in the posterior nucleus, which additionally received PT excitation. These findings, which contrast in several ways with previous observations in sensory areas, illuminate the basic circuit organization of CT neurons within M1 and between M1 and thalamus. PMID:25653383

  14. Lycopene inhibits regulator of calcineurin 1-mediated apoptosis by reducing oxidative stress and down-regulating Nucling in neuronal cells.

    Science.gov (United States)

    Lim, Seiyoung; Hwang, Sinwoo; Yu, Ji Hoon; Lim, Joo Weon; Kim, Hyeyoung

    2017-05-01

    Regulator of calcineurin 1 (RCAN1) is located on the Down syndrome critical region (DSCR) locus in human chromosome 21. Oxidative stress and overexpression of RCAN1 are implicated in neuronal impairment in Down's syndrome (DS) and Alzheimer's disease (AD). Serum level of lycopene, an antioxidant pigment, is low in DS and AD patients, which may be related to neuronal damage. The present study is to investigate whether lycopene inhibits apoptosis by reducing ROS levels, NF-κB activation, expression of the apoptosis regulator Nucling, cell viability, and indices of apoptosis (cytochrome c release, caspase-3 activation) in RCAN1-overexpressing neuronal cells. Cells transfected with either pcDNA or RCAN1 were treated with or without lycopene. Lycopene decreased intracellular and mitochondrial ROS levels, NF-κB activity, and Nucling expression while it reversed decrease in mitochondrial membrane potential, mitochondrial respiration, and glycolytic function in RCAN1-overexpressing cells. Lycopene inhibited cell death, DNA fragmentation, caspase-3 activation, and cytochrome c release in RCAN1-overexpressing cells. Lycopene inhibits RCAN1-mediated apoptosis by reducing ROS levels and by inhibiting NF-κB activation, Nucling induction, and the increase in apoptotic indices in neuronal cells. Consumption of lycopene-rich foods may prevent oxidative stress-associated neuronal damage in some pathologic conditions such as DS or AD. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Neuronal synchrony: peculiarity and generality.

    Science.gov (United States)

    Nowotny, Thomas; Huerta, Ramon; Rabinovich, Mikhail I

    2008-09-01

    Synchronization in neuronal systems is a new and intriguing application of dynamical systems theory. Why are neuronal systems different as a subject for synchronization? (1) Neurons in themselves are multidimensional nonlinear systems that are able to exhibit a wide variety of different activity patterns. Their "dynamical repertoire" includes regular or chaotic spiking, regular or chaotic bursting, multistability, and complex transient regimes. (2) Usually, neuronal oscillations are the result of the cooperative activity of many synaptically connected neurons (a neuronal circuit). Thus, it is necessary to consider synchronization between different neuronal circuits as well. (3) The synapses that implement the coupling between neurons are also dynamical elements and their intrinsic dynamics influences the process of synchronization or entrainment significantly. In this review we will focus on four new problems: (i) the synchronization in minimal neuronal networks with plastic synapses (synchronization with activity dependent coupling), (ii) synchronization of bursts that are generated by a group of nonsymmetrically coupled inhibitory neurons (heteroclinic synchronization), (iii) the coordination of activities of two coupled neuronal networks (partial synchronization of small composite structures), and (iv) coarse grained synchronization in larger systems (synchronization on a mesoscopic scale). (c) 2008 American Institute of Physics.

  16. Late calcium EDTA rescues hippocampal CA1 neurons from global ischemia-induced death.

    Science.gov (United States)

    Calderone, Agata; Jover, Teresa; Mashiko, Toshihiro; Noh, Kyung-min; Tanaka, Hidenobu; Bennett, Michael V L; Zukin, R Suzanne

    2004-11-03

    Transient global ischemia induces a delayed rise in intracellular Zn2+, which may be mediated via glutamate receptor 2 (GluR2)-lacking AMPA receptors (AMPARs), and selective, delayed death of hippocampal CA1 neurons. The molecular mechanisms underlying Zn2+ toxicity in vivo are not well delineated. Here we show the striking finding that intraventricular injection of the high-affinity Zn2+ chelator calcium EDTA (CaEDTA) at 30 min before ischemia (early CaEDTA) or at 48-60 hr (late CaEDTA), but not 3-6 hr, after ischemia, afforded robust protection of CA1 neurons in approximately 50% (late CaEDTA) to 75% (early CaEDTA) of animals. We also show that Zn2+ acts via temporally distinct mechanisms to promote neuronal death. Early CaEDTA attenuated ischemia-induced GluR2 mRNA and protein downregulation (and, by inference, formation of Zn2+-permeable AMPARs), the delayed rise in Zn2+, and neuronal death. These findings suggest that Zn2+ acts at step(s) upstream from GluR2 gene downregulation and implicate Zn2+ in transcriptional regulation and/or GluR2 mRNA stability. Early CaEDTA also blocked mitochondrial release of cytochrome c and Smac/DIABLO (second mitochondria-derived activator of caspases/direct inhibitor of apoptosis protein-binding protein with low pI), caspase-3 activity (but not procaspase-3 cleavage), p75NTR induction, and DNA fragmentation. These findings indicate that CaEDTA preserves the functional integrity of the mitochondrial outer membrane and arrests the caspase death cascade. Late injection of CaEDTA at a time when GluR2 is downregulated and caspase is activated inhibited the delayed rise in Zn2+, p75NTR induction, DNA fragmentation, and cell death. The finding of neuroprotection by late CaEDTA administration has striking implications for intervention in the delayed neuronal death associated with global ischemia.

  17. Examining the Panic Attack Specifier in Social Anxiety Disorder.

    Science.gov (United States)

    Allan, Nicholas P; Oglesby, Mary E; Short, Nicole A; Schmidt, Norman B

    2016-04-01

    Panic attacks (PAs) are characterized by overwhelming surges of fear and discomfort and are one of the most frequently occurring symptoms in psychiatric populations. The most recent version of the Diagnostic and Statistical Manual of Mental Disorders (i.e. DSM-5) allows for a panic attack (PA) specifier for all disorders, including social anxiety disorder (SAD). However, there is little research examining differences between individuals diagnosed with SAD with the PA specifier versus individuals diagnosed with SAD without the PA specifier. The current study examined social anxiety, mood, anxiety, and anxiety sensitivity social concerns, a risk factor for social anxiety in SAD-diagnosed individuals without (N = 52) and with (N = 14) the PA specifier. The groups differed only in somatic symptoms of anxiety. Result of the current study provides preliminary evidence that the presence of the PA specifier in social anxiety does not result in elevated levels of comorbidity or a more severe presentation of social anxiety.

  18. Localization of the kinesin adaptor proteins trafficking kinesin proteins 1 and 2 in primary cultures of hippocampal pyramidal and cortical neurons.

    Science.gov (United States)

    Loss, Omar; Stephenson, F Anne

    2015-07-01

    Neuronal function requires regulated anterograde and retrograde trafficking of mitochondria along microtubules by using the molecular motors kinesin and dynein. Previous work has established that trafficking kinesin proteins (TRAKs),TRAK1 and TRAK2, are kinesin adaptor proteins that link mitochondria to kinesin motor proteins via an acceptor protein in the mitochondrial outer membrane, etc. the Rho GTPase Miro. Recent studies have shown that TRAK1 preferentially controls mitochondrial transport in axons of hippocampal neurons by virtue of its binding to both kinesin and dynein motor proteins, whereas TRAK2 controls mitochondrial transport in dendrites resulting from its binding to dynein. This study further investigates the subcellular localization of TRAK1 and TRAK2 in primary cultures of hippocampal and cortical neurons by using both commercial antibodies and anti-TRAK1 and anti-TRAK2 antibodies raised in our own laboratory (in-house). Whereas TRAK1 was prevalently localized in axons of hippocampal and cortical neurons, TRAK2 was more prevalent in dendrites of hippocampal neurons. In cortical neurons, TRAK2 was equally distributed between axons and dendrites. Some qualitative differences were observed between commercial and in-house-generated antibody immunostaining. © 2015 Wiley Periodicals, Inc.

  19. Specifying Functional Requirements Dependency in the REWiki

    OpenAIRE

    ZHANG, ZHANG

    2013-01-01

    Most of the individual requirements cannot be treated in isolation. Requirements may affect each other in various ways. The dependency between requirements impacts a number of software development aspects and activities. How to classify and specify requirements dependency remains a classic research topic. This research aims at providing an approach of specifying functional requirements dependency. In this thesis we generalize a classification of functional requirements dependency. We also pro...

  20. Inhibition of RhoA GTPase and the subsequent activation of PTP1B protects cultured hippocampal neurons against amyloid β toxicity

    Directory of Open Access Journals (Sweden)

    Rodriguez-Tebar Alfredo

    2011-02-01

    Full Text Available Abstract Background Amyloid beta (Aβ is the main agent responsible for the advent and progression of Alzheimer's disease. This peptide can at least partially antagonize nerve growth factor (NGF signalling in neurons, which may be responsible for some of the effects produced by Aβ. Accordingly, better understanding the NGF signalling pathway may provide clues as to how to protect neurons from the toxic effects of Aβ. Results We show here that Aβ activates the RhoA GTPase by binding to p75NTR, thereby preventing the NGF-induced activation of protein tyrosine phosphatase 1B (PTP1B that is required for neuron survival. We also show that the inactivation of RhoA GTPase and the activation of PTP1B protect cultured hippocampal neurons against the noxious effects of Aβ. Indeed, either pharmacological inhibition of RhoA with C3 ADP ribosyl transferase or the transfection of cultured neurons with a dominant negative form of RhoA protects cultured hippocampal neurons from the effects of Aβ. In addition, over-expression of PTP1B also prevents the deleterious effects of Aβ on cultured hippocampal neurons. Conclusion Our findings indicate that potentiating the activity of NGF at the level of RhoA inactivation and PTP1B activation may represent a new means to combat the noxious effects of Aβ in Alzheimer's disease.

  1. Effects of kisspeptin1 on electrical activity of an extrahypothalamic population of gonadotropin-releasing hormone neurons in medaka (Oryzias latipes).

    Science.gov (United States)

    Zhao, Yali; Wayne, Nancy L

    2012-01-01

    Kisspeptin (product of the kiss1 gene) is the most potent known activator of the hypothalamo-pituitary-gonadal axis. Both kiss1 and the kisspeptin receptor are highly expressed in the hypothalamus of vertebrates, and low doses of kisspeptin have a robust and long-lasting stimulatory effect on the rate of action potential firing of hypophysiotropic gonadotropin releasing hormone-1 (GnRH1) neurons in mice. Fish have multiple populations of GnRH neurons distinguished by their location in the brain and the GnRH gene that they express. GnRH3 neurons located in the terminal nerve (TN) associated with the olfactory bulb are neuromodulatory and do not play a direct role in regulating pituitary-gonadal function. In medaka fish, the electrical activity of TN-GnRH3 neurons is modulated by visual cues from conspecifics, and is thought to act as a transmitter of information from the external environment to the central nervous system. TN-GnRH3 neurons also play a role in sexual motivation and arousal states, making them an important population of neurons to study for understanding coordination of complex behaviors. We investigated the role of kisspeptin in regulating electrical activity of TN-GnRH3 neurons in adult medaka. Using electrophysiology in an intact brain preparation, we show that a relatively brief treatment with 100 nM of kisspeptin had a long-lasting stimulatory effect on the electrical activity of an extrahypothalamic population of GnRH neurons. Dose-response analysis suggests a relatively narrow activational range of this neuropeptide. Further, blocking action potential firing with tetrodotoxin and blocking synaptic transmission with a low Ca(2+)/high Mg(2+) solution inhibited the stimulatory action of kisspeptin on electrical activity, indicating that kisspeptin is acting indirectly through synaptic regulation to excite TN-GnRH3 neurons. Our findings provide a new perspective on kisspeptin's broader functions within the central nervous system, through its

  2. Similar PDK1-AKT-mTOR pathway activation in balloon cells and dysmorphic neurons of type II focal cortical dysplasia with refractory epilepsy.

    Science.gov (United States)

    Lin, Yuan-xiang; Lin, Kun; Kang, De-zhi; Liu, Xin-xiu; Wang, Xing-fu; Zheng, Shu-fa; Yu, Liang-hong; Lin, Zhang-ya

    2015-05-01

    Dysmorphic neurons and balloon cells constitute the neuropathological hallmarks of type II focal cortical dysplasias (FCDs) with refractory epilepsy. The genesis of these cells may be critical to the histological findings in type II FCD. Recent work has shown enhanced activation of the mTOR cascade in both balloon cells and dysmorphic neurons, suggesting a common pathogenesis for these two neuropathological hallmarks. A direct comparative analysis of balloon cells and dysmorphic neurons might identify a molecular link between balloon cells and dysmorphic neurons. Here, we addressed whether PDK1-AKT-mTOR activation differentiates balloon cells from dysmorphic neurons. We used immunohistochemistry with antibodies against phosphorylated (p)-PDK1 (Ser241), p-AKT (Thr308), p-AKT (Ser473), p-mTOR (Ser2448), p-P70S6K (Thr229), and p-p70S6 kinase (Thr389) in balloon cells compared with dysmorphic neurons. Strong or moderate staining for components of the PDK1-AKT-mTOR signaling pathway was observed in both balloon cells and dysmorphic neurons. However, only a few pyramidal neurons displayed weak staining in control group (perilesional neocortex and histologically normal neocortex). Additionally, p-PDK1 (Ser241) and p-AKT (Thr308) staining in balloon cells were stronger than in dysmorphic neurons, whereas p-P70S6K (Thr229) and p-p70S6 kinase (Thr389) staining in balloon cells was weaker than in dysmorphic neurons. In balloon cells, p-AKT (Ser473) and p-mTOR (Ser2448) staining was comparable with the staining in dysmorphic neurons. Our data support the previously suggested pathogenic relationship between balloon cells and dysmorphic neurons concerning activation of the PDK1-AKT-mTOR, which may play important roles in the pathogenesis of type II FCD. Differential expression of some components of the PDK1-AKT-mTOR pathway between balloon cells and dysmorphic neurons may result from cell-specific gene expression. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Optogenetic Stimulation of Locus Ceruleus Neurons Augments Inhibitory Transmission to Parasympathetic Cardiac Vagal Neurons via Activation of Brainstem α1 and β1 Receptors

    OpenAIRE

    Wang, Xin; Piñol, Ramón A.; Byrne, Peter; Mendelowitz, David

    2014-01-01

    Locus ceruleus (LC) noradrenergic neurons are critical in generating alertness. In addition to inducing cortical arousal, the LC also orchestrates changes in accompanying autonomic system function that compliments increased attention, such as during stress, excitation, and/or exposure to averse or novel stimuli. Although the association between arousal and increased heart rate is well accepted, the neurobiological link between the LC and parasympathetic neurons that control heart rate has not...

  4. Stochastic models for spike trains of single neurons

    CERN Document Server

    Sampath, G

    1977-01-01

    1 Some basic neurophysiology 4 The neuron 1. 1 4 1. 1. 1 The axon 7 1. 1. 2 The synapse 9 12 1. 1. 3 The soma 1. 1. 4 The dendrites 13 13 1. 2 Types of neurons 2 Signals in the nervous system 14 2. 1 Action potentials as point events - point processes in the nervous system 15 18 2. 2 Spontaneous activi~ in neurons 3 Stochastic modelling of single neuron spike trains 19 3. 1 Characteristics of a neuron spike train 19 3. 2 The mathematical neuron 23 4 Superposition models 26 4. 1 superposition of renewal processes 26 4. 2 Superposition of stationary point processe- limiting behaviour 34 4. 2. 1 Palm functions 35 4. 2. 2 Asymptotic behaviour of n stationary point processes superposed 36 4. 3 Superposition models of neuron spike trains 37 4. 3. 1 Model 4. 1 39 4. 3. 2 Model 4. 2 - A superposition model with 40 two input channels 40 4. 3. 3 Model 4. 3 4. 4 Discussion 41 43 5 Deletion models 5. 1 Deletion models with 1nd~endent interaction of excitatory and inhibitory sequences 44 VI 5. 1. 1 Model 5. 1 The basic de...

  5. AgRP neurons regulate development of dopamine neuronal plasticity and nonfood-associated behaviors

    Science.gov (United States)

    Dietrich, Marcelo O; Bober, Jeremy; Ferreira, Jozélia G; Tellez, Luis A; Mineur, Yann S; Souza, Diogo O; Gao, Xiao-Bing; Picciotto, Marina R; Araújo, Ivan; Liu, Zhong-Wu; Horvath, Tamas L

    2012-01-01

    It is not known whether behaviors unrelated to feeding are affected by hypothalamic regulators of hunger. We found that impairment of Agouti-related protein (AgRP) circuitry by either Sirt1 knockdown in AgRP-expressing neurons or early postnatal ablation of these neurons increased exploratory behavior and enhanced responses to cocaine. In AgRP circuit–impaired mice, ventral tegmental dopamine neurons exhibited enhanced spike timing–dependent long-term potentiation, altered amplitude of miniature postsynaptic currents and elevated dopamine in basal forebrain. Thus, AgRP neurons determine the set point of the reward circuitry and associated behaviors. PMID:22729177

  6. Kappe neurons, a novel population of olfactory sensory neurons.

    Science.gov (United States)

    Ahuja, Gaurav; Bozorg Nia, Shahrzad; Zapilko, Veronika; Shiriagin, Vladimir; Kowatschew, Daniel; Oka, Yuichiro; Korsching, Sigrun I

    2014-02-10

    Perception of olfactory stimuli is mediated by distinct populations of olfactory sensory neurons, each with a characteristic set of morphological as well as functional parameters. Beyond two large populations of ciliated and microvillous neurons, a third population, crypt neurons, has been identified in teleost and cartilaginous fishes. We report here a novel, fourth olfactory sensory neuron population in zebrafish, which we named kappe neurons for their characteristic shape. Kappe neurons are identified by their Go-like immunoreactivity, and show a distinct spatial distribution within the olfactory epithelium, similar to, but significantly different from that of crypt neurons. Furthermore, kappe neurons project to a single identified target glomerulus within the olfactory bulb, mdg5 of the mediodorsal cluster, whereas crypt neurons are known to project exclusively to the mdg2 glomerulus. Kappe neurons are negative for established markers of ciliated, microvillous and crypt neurons, but appear to have microvilli. Kappe neurons constitute the fourth type of olfactory sensory neurons reported in teleost fishes and their existence suggests that encoding of olfactory stimuli may require a higher complexity than hitherto assumed already in the peripheral olfactory system.

  7. Multiple pathways of sigma(1) receptor ligand uptakes into primary cultured neuronal cells.

    Science.gov (United States)

    Yamamoto, H; Karasawa, J; Sagi, N; Takahashi, S; Horikomi, K; Okuyama, S; Nukada, T; Sora, I; Yamamoto, T

    2001-08-03

    Although many antipsychotics have affinities for sigma receptors, the transportation pathway of exogenous sigma(1) receptor ligands to intracellular type-1 sigma receptors are not fully understood. In this study, sigma(1) receptor ligand uptakes were studied using primary cultured neuronal cells. [(3)H](+)-pentazocine and [(3)H](R)-(+)-1-(4-chlorophenyl)-3-[4-(2-methoxyethyl)piperazin-1-yl]methyl-2-pyrrolidinone L-tartrate (MS-377), used as a selective sigma(1) receptor ligands, were taken up in a time-, energy- and temperature-dependent manner, suggesting that active transport mechanisms were involved in their uptakes. sigma(1) receptor ligands taken up into primary cultured neuronal cells were not restricted to agonists, but also concerned antagonists. The uptakes of these ligands were mainly Na(+)-independent. Kinetic analysis of [(3)H](+)-pentazocine and [(3)H]MS-377 uptake showed K(m) values (microM) of 0.27 and 0.32, and V(max) values (pmol/mg protein/min) of 17.4 and 9.4, respectively. Although both ligands were incorporated, the pharmacological properties of these two ligands were different. Uptake of [(3)H](+)-pentazocine was inhibited in the range 0.4-7.1 microM by all the sigma(1) receptor ligands used, including N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine monohydrochloride (NE-100), a selective sigma(1) receptor ligand. In contrast, the inhibition of [(3)H]MS-377 uptake was potently inhibited by haloperidol, characterized by supersensitivity (IC(50), approximately 2 nM) and was inhibited by NE-100 with low sensitivity (IC(50), 4.5 microM). Moreover, kinetic analysis revealed that NE-100 inhibited [(3)H]MS-377 uptake in a noncompetitive manner, suggesting that NE-100 acted at a site different from the uptake sites of [(3)H]MS-377. These findings suggest that there are at least two uptake pathways for sigma(1) receptor ligands in primary cultured neuronal cells (i.e. a haloperidol-sensitive pathway and another, unclear, pathway). In

  8. Functional and neurochemical characterization of angiotensin type 1A receptor-expressing neurons in the nucleus of the solitary tract of the mouse.

    Science.gov (United States)

    Carter, D A; Choong, Y-T; Connelly, A A; Bassi, J K; Hunter, N O; Thongsepee, N; Llewellyn-Smith, I J; Fong, A Y; McDougall, S J; Allen, A M

    2017-10-01

    Angiotensin II acts via two main receptors within the central nervous system, with the type 1A receptor (AT 1A R) most widely expressed in adult neurons. Activation of the AT 1 R in the nucleus of the solitary tract (NTS), the principal nucleus receiving central synapses of viscerosensory afferents, modulates cardiovascular reflexes. Expression of the AT 1 R occurs in high density within the NTS of most mammals, including humans, but the fundamental electrophysiological and neurochemical characteristics of the AT 1A R-expressing NTS neurons are not known. To address this, we have used a transgenic mouse, in which the AT 1A R promoter drives expression of green fluorescent protein (GFP). Approximately one-third of AT 1A R-expressing neurons express the catecholamine-synthetic enzyme tyrosine hydroxylase (TH), and a subpopulation of these stained for the transcription factor paired-like homeobox 2b (Phox2b). A third group, comprising approximately two-thirds of the AT 1A R-expressing NTS neurons, showed Phox2b immunoreactivity alone. A fourth group in the ventral subnucleus expressed neither TH nor Phox2b. In whole cell recordings from slices in vitro, AT 1A R-GFP neurons exhibited voltage-activated potassium currents, including the transient outward current and the M-type potassium current. In two different mouse strains, both AT 1A R-GFP neurons and TH-GFP neurons showed similar AT 1A R-mediated depolarizing responses to superfusion with angiotensin II. These data provide a comprehensive description of AT 1A R-expressing neurons in the NTS and increase our understanding of the complex actions of this neuropeptide in the modulation of viscerosensory processing. Copyright © 2017 the American Physiological Society.

  9. Nuclear 82-kDa choline acetyltransferase decreases amyloidogenic APP metabolism in neurons from APP/PS1 transgenic mice.

    Science.gov (United States)

    Albers, Shawn; Inthathirath, Fatima; Gill, Sandeep K; Winick-Ng, Warren; Jaworski, Ewa; Wong, Daisy Y L; Gros, Robert; Rylett, R Jane

    2014-09-01

    Alzheimer disease (AD) is associated with increased amyloidogenic processing of amyloid precursor protein (APP) to β-amyloid peptides (Aβ), cholinergic neuron loss with decreased choline acetyltransferase (ChAT) activity, and cognitive dysfunction. Both 69-kDa ChAT and 82-kDa ChAT are expressed in cholinergic neurons in human brain and spinal cord with 82-kDa ChAT localized predominantly to neuronal nuclei, suggesting potential alternative functional roles for the enzyme. By gene microarray analysis, we found that 82-kDa ChAT-expressing IMR32 neural cells have altered expression of genes involved in diverse cellular functions. Importantly, genes for several proteins that regulate APP processing along amyloidogenic and non-amyloidogenic pathways are differentially expressed in 82-kDa ChAT-containing cells. The predicted net effect based on observed changes in expression patterns of these genes would be decreased amyloidogenic APP processing with decreased Aβ production. This functional outcome was verified experimentally as a significant decrease in BACE1 protein levels and activity and a concomitant reduction in the release of endogenous Aβ1-42 from neurons cultured from brains of AD-model APP/PS1 transgenic mice. The expression of 82-kDa ChAT in neurons increased levels of GGA3, which is involved in trafficking BACE1 to lysosomes for degradation. shRNA-induced decreases in GGA3 protein levels attenuated the 82-kDa ChAT-mediated decreases in BACE1 protein and activity and Aβ1-42 release. Evidence that 82-kDa ChAT can enhance GGA3 gene expression is shown by enhanced GGA3 gene promoter activity in SN56 neural cells expressing this ChAT protein. These studies indicate a novel relationship between cholinergic neurons and APP processing, with 82-kDa ChAT acting as a negative regulator of Aβ production. This decreased formation of Aβ could result in protection for cholinergic neurons, as well as protection of other cells in the vicinity that are sensitive to

  10. Sustained expression of a neuron-specific isoform of the Taf1 gene in development stages and aging in mice

    International Nuclear Information System (INIS)

    Jambaldorj, Jamiyansuren; Makino, Satoshi; Munkhbat, Batmunkh; Tamiya, Gen

    2012-01-01

    Highlights: ► We identified the mouse homologue of neuron-specific TAF1 (N-Taf1). ► Taf1 mRNA was expressed in most tissues and cell lines. ► N-Taf1 mRNA was expressed in the brain and Neuroblastoma N2a cell lines. ► Taf1 and N-Taf1 showed different expression profile in development stage and aging. -- Abstract: TATA-box binding protein associated factor 1 (TAF1) protein is the largest and the essential component of the TFIID complex in the pathway of RNA polymerase II–mediated gene transcription, and it regulates transcription of a large number of genes related to cell division. The neuron-specific isoform of the TAF1 gene (N-TAF1), which we reported previously, may have an essential role in neurons through transcriptional regulation of many neuron-specific genes. In the present study, we cloned the full-length cDNA that encodes the mouse homologue of N-TAF1 (N-Taf1) protein. By carrying out of real time RT-PCR, we investigated the expression analysis of the N-Taf1 mRNA in mouse tissues and cell lines. As well as the human N-TAF1, the N-Taf1 showed limited expression in the brain and neuroblastoma, whereas Taf1 expressed elsewhere. Furthermore, in mouse embryo head or mouse brain, mRNA expression of TAF1 changes dramatically during development but N-Taf1 showed sustained expression. Our result suggests that the N-Taf1 gene has an important role in non-dividing neuronal cell rather than in cell division and proliferation during neurogenesis.

  11. Sustained expression of a neuron-specific isoform of the Taf1 gene in development stages and aging in mice

    Energy Technology Data Exchange (ETDEWEB)

    Jambaldorj, Jamiyansuren [Department of Pharmacology, Institute of Health Biosciences, Graduate School, The University of Tokushima, Tokushima 770-8503 (Japan); Advanced Molecular Epidemiology Research Institute, Yamagata University Faculty of Medicine, Yamagata 990-9585 (Japan); Central Scientific Research Laboratory, Institute of Medical Sciences, Ulaanbaatar (Mongolia); Makino, Satoshi, E-mail: smakino@genetix-h.com [Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu 520-2192 (Japan); Munkhbat, Batmunkh [Central Scientific Research Laboratory, Institute of Medical Sciences, Ulaanbaatar (Mongolia); Tamiya, Gen [Advanced Molecular Epidemiology Research Institute, Yamagata University Faculty of Medicine, Yamagata 990-9585 (Japan)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer We identified the mouse homologue of neuron-specific TAF1 (N-Taf1). Black-Right-Pointing-Pointer Taf1 mRNA was expressed in most tissues and cell lines. Black-Right-Pointing-Pointer N-Taf1 mRNA was expressed in the brain and Neuroblastoma N2a cell lines. Black-Right-Pointing-Pointer Taf1 and N-Taf1 showed different expression profile in development stage and aging. -- Abstract: TATA-box binding protein associated factor 1 (TAF1) protein is the largest and the essential component of the TFIID complex in the pathway of RNA polymerase II-mediated gene transcription, and it regulates transcription of a large number of genes related to cell division. The neuron-specific isoform of the TAF1 gene (N-TAF1), which we reported previously, may have an essential role in neurons through transcriptional regulation of many neuron-specific genes. In the present study, we cloned the full-length cDNA that encodes the mouse homologue of N-TAF1 (N-Taf1) protein. By carrying out of real time RT-PCR, we investigated the expression analysis of the N-Taf1 mRNA in mouse tissues and cell lines. As well as the human N-TAF1, the N-Taf1 showed limited expression in the brain and neuroblastoma, whereas Taf1 expressed elsewhere. Furthermore, in mouse embryo head or mouse brain, mRNA expression of TAF1 changes dramatically during development but N-Taf1 showed sustained expression. Our result suggests that the N-Taf1 gene has an important role in non-dividing neuronal cell rather than in cell division and proliferation during neurogenesis.

  12. The lactate receptor HCAR1 promotes neuronal development and protects axons and myelin during hypoglycemia

    DEFF Research Database (Denmark)

    Kennedy, L. H.; Andersson, K. A.; Haugen, O. P.

    2017-01-01

    Lactate plays a significant role as an energy supply for neurons and has a neuroprotective effect in hypoglycemia and ischemia (1±5). Further, oligodendrocytes can use lactate for myelination when glucose levels are low. New studies suggest that lactate is not only a metabolic fuel but also...... in the development and survival of neurons and oligodendrocytes in normal conditions and hypoglycemia. We show that young HCAR1 KO mice have a reduced number of neural progenitor cells in the hippocampus and the cerebral cortex, and the average size of cortical axons is smaller in KO compared with WT mice...

  13. A cAMP/PKA/Kinesin-1 Axis Promotes the Axonal Transport of Mitochondria in Aging Drosophila Neurons.

    Science.gov (United States)

    Vagnoni, Alessio; Bullock, Simon L

    2018-04-23

    Mitochondria play fundamental roles within cells, including energy provision, calcium homeostasis, and the regulation of apoptosis. The transport of mitochondria by microtubule-based motors is critical for neuronal structure and function. This process allows local requirements for mitochondrial functions to be met and also facilitates recycling of these organelles [1, 2]. An age-related reduction in mitochondrial transport has been observed in neurons of mammalian and non-mammalian organisms [3-6], and has been proposed to contribute to the broader decline in neuronal function that occurs during aging [3, 5-7]. However, the factors that influence mitochondrial transport in aging neurons are poorly understood. Here we provide evidence using the tractable Drosophila wing nerve system that the cyclic AMP/protein kinase A (cAMP/PKA) pathway promotes the axonal transport of mitochondria in adult neurons. The level of the catalytic subunit of PKA decreases during aging, and acute activation of the cAMP/PKA pathway in aged flies strongly stimulates mitochondrial motility. Thus, the age-related impairment of transport is reversible. The expression of many genes is increased by PKA activation in aged flies. However, our results indicate that elevated mitochondrial transport is due in part to upregulation of the heavy chain of the kinesin-1 motor, the level of which declines during aging. Our study identifies evolutionarily conserved factors that can strongly influence mitochondrial motility in aging neurons. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  14. The role of MAC1 in diesel exhaust particle-induced microglial activation and loss of dopaminergic neuron function.

    Science.gov (United States)

    Levesque, Shannon; Taetzsch, Thomas; Lull, Melinda E; Johnson, Jo Anne; McGraw, Constance; Block, Michelle L

    2013-06-01

    Increasing reports support that air pollution causes neuroinflammation and is linked to central nervous system (CNS) disease/damage. Diesel exhaust particles (DEP) are a major component of urban air pollution, which has been linked to microglial activation and Parkinson's disease-like pathology. To begin to address how DEP may exert CNS effects, microglia and neuron-glia cultures were treated with either nanometer-sized DEP (neuron function was assessed. All three treatments showed enhanced ameboid microglia morphology, increased H2 O2 production, and decreased DA uptake. Mechanistic inquiry revealed that the scavenger receptor inhibitor fucoidan blocked DEP internalization in microglia, but failed to alter DEP-induced H2 O2 production in microglia. However, pre-treatment with the MAC1/CD11b inhibitor antibody blocked microglial H2 O2 production in response to DEP. MAC1(-/-) mesencephalic neuron-glia cultures were protected from DEP-induced loss of DA neuron function, as measured by DA uptake. These findings support that DEP may activate microglia through multiple mechanisms, where scavenger receptors regulate internalization of DEP and the MAC1 receptor is mandatory for both DEP-induced microglial H2 O2 production and loss of DA neuron function. © 2013 International Society for Neurochemistry.

  15. IL-10 Promotes Neurite Outgrowth and Synapse Formation in Cultured Cortical Neurons after the Oxygen-Glucose Deprivation via JAK1/STAT3 Pathway.

    Science.gov (United States)

    Chen, Hongbin; Lin, Wei; Zhang, Yixian; Lin, Longzai; Chen, Jianhao; Zeng, Yongping; Zheng, Mouwei; Zhuang, Zezhong; Du, Houwei; Chen, Ronghua; Liu, Nan

    2016-07-26

    As a classic immunoregulatory and anti-inflammatory cytokine, interleukin-10 (IL-10) provides neuroprotection in cerebral ischemia in vivo or oxygen-glucose deprivation (OGD)-induced injury in vitro. However, it remains blurred whether IL-10 promotes neurite outgrowth and synapse formation in cultured primary cortical neurons after OGD injury. In order to evaluate its effect on neuronal apoptosis, neurite outgrowth and synapse formation, we administered IL-10 or IL-10 neutralizing antibody (IL-10NA) to cultured rat primary cortical neurons after OGD injury. We found that IL-10 treatment activated the Janus kinase 1 (JAK1)/signal transducers and activators of transcription 3 (STAT3) signaling pathway. Moreover, IL-10 attenuated OGD-induced neuronal apoptosis by down-regulating the Bax expression and up-regulating the Bcl-2 expression, facilitated neurite outgrowth by increasing the expression of Netrin-1, and promoted synapse formation in cultured primary cortical neurons after OGD injury. These effects were partly abolished by JAK1 inhibitor GLPG0634. Contrarily, IL-10NA produced opposite effects on the cultured cortical neurons after OGD injury. Taken together, our findings suggest that IL-10 not only attenuates neuronal apoptosis, but also promotes neurite outgrowth and synapse formation via the JAK1/STAT3 signaling pathway in cultured primary cortical neurons after OGD injury.

  16. A New Population of Parvocellular Oxytocin Neurons Controlling Magnocellular Neuron Activity and Inflammatory Pain Processing.

    Science.gov (United States)

    Eliava, Marina; Melchior, Meggane; Knobloch-Bollmann, H Sophie; Wahis, Jérôme; da Silva Gouveia, Miriam; Tang, Yan; Ciobanu, Alexandru Cristian; Triana Del Rio, Rodrigo; Roth, Lena C; Althammer, Ferdinand; Chavant, Virginie; Goumon, Yannick; Gruber, Tim; Petit-Demoulière, Nathalie; Busnelli, Marta; Chini, Bice; Tan, Linette L; Mitre, Mariela; Froemke, Robert C; Chao, Moses V; Giese, Günter; Sprengel, Rolf; Kuner, Rohini; Poisbeau, Pierrick; Seeburg, Peter H; Stoop, Ron; Charlet, Alexandre; Grinevich, Valery

    2016-03-16

    Oxytocin (OT) is a neuropeptide elaborated by the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei. Magnocellular OT neurons of these nuclei innervate numerous forebrain regions and release OT into the blood from the posterior pituitary. The PVN also harbors parvocellular OT cells that project to the brainstem and spinal cord, but their function has not been directly assessed. Here, we identified a subset of approximately 30 parvocellular OT neurons, with collateral projections onto magnocellular OT neurons and neurons of deep layers of the spinal cord. Evoked OT release from these OT neurons suppresses nociception and promotes analgesia in an animal model of inflammatory pain. Our findings identify a new population of OT neurons that modulates nociception in a two tier process: (1) directly by release of OT from axons onto sensory spinal cord neurons and inhibiting their activity and (2) indirectly by stimulating OT release from SON neurons into the periphery. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Alterations to dendritic spine morphology, but not dendrite patterning, of cortical projection neurons in Tc1 and Ts1Rhr mouse models of Down syndrome.

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    Matilda A Haas

    Full Text Available Down Syndrome (DS is a highly prevalent developmental disorder, affecting 1/700 births. Intellectual disability, which affects learning and memory, is present in all cases and is reflected by below average IQ. We sought to determine whether defective morphology and connectivity in neurons of the cerebral cortex may underlie the cognitive deficits that have been described in two mouse models of DS, the Tc1 and Ts1Rhr mouse lines. We utilised in utero electroporation to label a cohort of future upper layer projection neurons in the cerebral cortex of developing mouse embryos with GFP, and then examined neuronal positioning and morphology in early adulthood, which revealed no alterations in cortical layer position or morphology in either Tc1 or Ts1Rhr mouse cortex. The number of dendrites, as well as dendrite length and branching was normal in both DS models, compared with wildtype controls. The sites of projection neuron synaptic inputs, dendritic spines, were analysed in Tc1 and Ts1Rhr cortex at three weeks and three months after birth, and significant changes in spine morphology were observed in both mouse lines. Ts1Rhr mice had significantly fewer thin spines at three weeks of age. At three months of age Tc1 mice had significantly fewer mushroom spines--the morphology associated with established synaptic inputs and learning and memory. The decrease in mushroom spines was accompanied by a significant increase in the number of stubby spines. This data suggests that dendritic spine abnormalities may be a more important contributor to cognitive deficits in DS models, rather than overall neuronal architecture defects.

  18. Mangiferin Upregulates Glyoxalase 1 Through Activation of Nrf2/ARE Signaling in Central Neurons Cultured with High Glucose.

    Science.gov (United States)

    Liu, Yao-Wu; Cheng, Ya-Qin; Liu, Xiao-Li; Hao, Yun-Chao; Li, Yu; Zhu, Xia; Zhang, Fan; Yin, Xiao-Xing

    2017-08-01

    Mangiferin, a natural C-glucoside xanthone, has anti-inflammatory, anti-oxidative, neuroprotective actions. Our previous study showed that mangiferin could attenuate diabetes-associated cognitive impairment of rats by enhancing the function of glyoxalase 1 (Glo-1) in brain. The aim of this study was to investigate whether Glo-1 upregulation by mangiferin in central neurons exposed to chronic high glucose may be related to activation of Nrf2/ARE pathway. Compared with normal glucose (25 mmol/L) culture, Glo-1 protein, mRNA, and activity levels were markedly decreased in primary hippocampal and cerebral cortical neurons cultured with high glucose (50 mmol/L) for 72 h, accompanied by the declined Nrf2 nuclear translocation and protein expression of Nrf2 in cell nucleus, as well as protein expression and mRNA level of γ-glutamylcysteine synthetase (γ-GCS) and superoxide dismutase activity, target genes of Nrf2/ARE signaling. Nonetheless, high glucose cotreating with mangiferin or sulforaphane, a typical inducer of Nrf2 activation, attenuated the above changes in both central neurons. In addition, mangiferin and sulforaphane significantly prevented the formation of advanced glycation end-products (AGEs) reflecting Glo-1 activity, while elevated the level of glutathione, a cofactor of Glo-1 activity and production of γ-GCS, in high glucose cultured central neurons. These findings demonstrated that Glo-1 was greatly downregulated in central neurons exposed to chronic high glucose, which is expected to lead the formation of AGEs and oxidative stress damages. We also proved that mangiferin enhanced the function of Glo-1 under high glucose condition by inducing activation of Nrf2/ARE signaling pathway.

  19. APE1, the DNA base excision repair protein, regulates the removal of platinum adducts in sensory neuronal cultures by NER

    International Nuclear Information System (INIS)

    Kim, Hyun-Suk; Guo, Chunlu; Thompson, Eric L.; Jiang, Yanlin; Kelley, Mark R.; Vasko, Michael R.; Lee, Suk-Hee

    2015-01-01

    Peripheral neuropathy is one of the major side effects of treatment with the anticancer drug, cisplatin. One proposed mechanism for this neurotoxicity is the formation of platinum adducts in sensory neurons that could contribute to DNA damage. Although this damage is largely repaired by nuclear excision repair (NER), our previous findings suggest that augmenting the base excision repair pathway (BER) by overexpressing the repair protein APE1 protects sensory neurons from cisplatin-induced neurotoxicity. The question remains whether APE1 contributes to the ability of the NER pathway to repair platinum-damage in neuronal cells. To examine this, we manipulated APE1 expression in sensory neuronal cultures and measured Pt-removal after exposure to cisplatin. When neuronal cultures were treated with increasing concentrations of cisplatin for two or three hours, there was a concentration-dependent increase in Pt-damage that peaked at four hours and returned to near baseline levels after 24 h. In cultures where APE1 expression was reduced by ∼80% using siRNA directed at APE1, there was a significant inhibition of Pt-removal over eight hours which was reversed by overexpressing APE1 using a lentiviral construct for human wtAPE1. Overexpressing a mutant APE1 (C65 APE1), which only has DNA repair activity, but not its other significant redox-signaling function, mimicked the effects of wtAPE1. Overexpressing DNA repair activity mutant APE1 (226 + 177APE1), with only redox activity was ineffective suggesting it is the DNA repair function of APE1 and not its redox-signaling, that restores the Pt-damage removal. Together, these data provide the first evidence that a critical BER enzyme, APE1, helps regulate the NER pathway in the repair of cisplatin damage in sensory neurons

  20. APE1, the DNA base excision repair protein, regulates the removal of platinum adducts in sensory neuronal cultures by NER

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Suk [Department of Biochemistry and Molecular Biology, Indianapolis, IN 46202 (United States); Guo, Chunlu; Thompson, Eric L. [Department of Pharmacology and Toxicology, Indianapolis, IN 46202 (United States); Jiang, Yanlin [Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Kelley, Mark R. [Department of Biochemistry and Molecular Biology, Indianapolis, IN 46202 (United States); Department of Pharmacology and Toxicology, Indianapolis, IN 46202 (United States); Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Vasko, Michael R. [Department of Pharmacology and Toxicology, Indianapolis, IN 46202 (United States); Lee, Suk-Hee, E-mail: slee@iu.edu [Department of Biochemistry and Molecular Biology, Indianapolis, IN 46202 (United States)

    2015-09-15

    Peripheral neuropathy is one of the major side effects of treatment with the anticancer drug, cisplatin. One proposed mechanism for this neurotoxicity is the formation of platinum adducts in sensory neurons that could contribute to DNA damage. Although this damage is largely repaired by nuclear excision repair (NER), our previous findings suggest that augmenting the base excision repair pathway (BER) by overexpressing the repair protein APE1 protects sensory neurons from cisplatin-induced neurotoxicity. The question remains whether APE1 contributes to the ability of the NER pathway to repair platinum-damage in neuronal cells. To examine this, we manipulated APE1 expression in sensory neuronal cultures and measured Pt-removal after exposure to cisplatin. When neuronal cultures were treated with increasing concentrations of cisplatin for two or three hours, there was a concentration-dependent increase in Pt-damage that peaked at four hours and returned to near baseline levels after 24 h. In cultures where APE1 expression was reduced by ∼80% using siRNA directed at APE1, there was a significant inhibition of Pt-removal over eight hours which was reversed by overexpressing APE1 using a lentiviral construct for human wtAPE1. Overexpressing a mutant APE1 (C65 APE1), which only has DNA repair activity, but not its other significant redox-signaling function, mimicked the effects of wtAPE1. Overexpressing DNA repair activity mutant APE1 (226 + 177APE1), with only redox activity was ineffective suggesting it is the DNA repair function of APE1 and not its redox-signaling, that restores the Pt-damage removal. Together, these data provide the first evidence that a critical BER enzyme, APE1, helps regulate the NER pathway in the repair of cisplatin damage in sensory neurons.

  1. Disruption of astrocyte-neuron cholesterol cross talk affects neuronal function in Huntington's disease.

    Science.gov (United States)

    Valenza, M; Marullo, M; Di Paolo, E; Cesana, E; Zuccato, C; Biella, G; Cattaneo, E

    2015-04-01

    In the adult brain, neurons require local cholesterol production, which is supplied by astrocytes through apoE-containing lipoproteins. In Huntington's disease (HD), such cholesterol biosynthesis in the brain is severely reduced. Here we show that this defect, occurring in astrocytes, is detrimental for HD neurons. Astrocytes bearing the huntingtin protein containing increasing CAG repeats secreted less apoE-lipoprotein-bound cholesterol in the medium. Conditioned media from HD astrocytes and lipoprotein-depleted conditioned media from wild-type (wt) astrocytes were equally detrimental in a neurite outgrowth assay and did not support synaptic activity in HD neurons, compared with conditions of cholesterol supplementation or conditioned media from wt astrocytes. Molecular perturbation of cholesterol biosynthesis and efflux in astrocytes caused similarly altered astrocyte-neuron cross talk, whereas enhancement of glial SREBP2 and ABCA1 function reversed the aspects of neuronal dysfunction in HD. These findings indicate that astrocyte-mediated cholesterol homeostasis could be a potential therapeutic target to ameliorate neuronal dysfunction in HD.

  2. Progranulin Reduced Neuronal Cell Death by Activation of Sortilin 1 Signaling Pathways After Subarachnoid Hemorrhage in Rats.

    Science.gov (United States)

    Li, Bo; He, Yue; Xu, Liang; Hu, Qin; Tang, Junjia; Chen, Yujie; Tang, Jiping; Feng, Hua; Zhang, John H

    2015-08-01

    Progranulin has been reported to have neuroprotective actions in cultured neurons. This study investigated the effect of recombinant rat progranulin on early brain injury after subarachnoid hemorrhage. Controlled in vivo laboratory study. Animal research laboratory. Two hundred thirty adult male Sprague-Dawley rats weighing 280-320 g. Subarachnoid hemorrhage was induced in rats by endovascular perforation. Rat recombinant progranulin (1 and 3 ng) was administrated intracerebroventricularly at 1.5 hours after subarachnoid hemorrhage. Progranulin small interfering RNA was administrated by intracerebroventricularly at 1 day before subarachnoid hemorrhage induction. Subarachnoid hemorrhage grade, neurologic score, and brain water content were measured at 24 and 72 hours after subarachnoid hemorrhage. Neural apoptosis was evaluated by double immunofluorescence staining using terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick-end labeling and neuronal nuclei. For mechanistic study, the expression of progranulin, phosphorylated Akt, Akt, p-Erk, Erk, Bcl-2, and cleaved caspase-3 were analyzed by Western blot at 24 hours after subarachnoid hemorrhage. siRNA for sortilin 1 (a progranulin receptor) was used to intervene the downstream pathway. The expression of progranulin decreased and reached the lowest point at 24 hours after subarachnoid hemorrhage. Administration of rat recombinant progranulin decreased brain water content and improved neurologic functions at both 24 and 72 hours after subarachnoid hemorrhage, while knockdown of endogenous progranulin aggravated neurologic deficits after subarachnoid hemorrhage. Rat recombinant progranulin treatment reduced neuronal apoptosis, while progranulin deficiency promoted neuronal apoptosis at 24 hours after subarachnoid hemorrhage. Rat recombinant progranulin promoted Akt activation, increased Bcl-2 level, but reduced caspase-3 level. Knockdown of progranulin binding factor sortilin 1

  3. Estradiol pretreatment ameliorates impaired synaptic plasticity at synapses of insulted CA1 neurons after transient global ischemia

    Science.gov (United States)

    Takeuchi, Koichi; Yang, Yupeng; Takayasu, Yukihiro; Gertner, Michael; Hwang, Jee-Yeon; Aromolaran, Kelly; Bennett, Michael V.L.; Zukin, R. Suzanne

    2015-01-01

    Global ischemia in humans or induced experimentally in animals causes selective and delayed neuronal death in pyramidal neurons of the hippocampal CA1. The ovarian hormone estradiol administered before or immediately after insult affords histological protection in experimental models of focal and global ischemia and ameliorates the cognitive deficits associated with ischemic cell death. However, the impact of estradiol on the functional integrity of Schaffer collateral to CA1 (Sch-CA1) pyramidal cell synapses following global ischemia is not clear. Here we show that long term estradiol treatment initiated 14 days prior to global ischemia in ovariectomized female rats acts via the IGF-1 receptor to protect the functional integrity of CA1 neurons. Global ischemia impairs basal synaptic transmission, assessed by the input/output relation at Sch-CA1 synapses, and NMDA receptor (NMDAR)-dependent long term potentiation (LTP), assessed at 3 days after surgery. Presynaptic function, assessed by fiber volley and paired pulse facilitation, is unchanged. To our knowledge, our results are the first to demonstrate that estradiol at near physiological concentrations enhances basal excitatory synaptic transmission and ameliorates deficits in LTP at synapses onto CA1 neurons in a clinically-relevant model of global ischemia. Estradiol-induced rescue of LTP requires the IGF-1 receptor, but not the classical estrogen receptors (ER)-α or β. These findings support a model whereby estradiol acts via the IGF-1 receptor to maintain the functional integrity of hippocampal CA1 synapses in the face of global ischemia. PMID:25463028

  4. Improving the Delivery of SOD1 Antisense Oligonucleotides to Motor Neurons Using Calcium Phosphate-Lipid Nanoparticles

    Directory of Open Access Journals (Sweden)

    Liyu Chen

    2017-08-01

    Full Text Available Amyotrophic Lateral Sclerosis (ALS is a fatal neurodegenerative disease affecting the upper and lower motor neurons in the motor cortex and spinal cord. Abnormal accumulation of mutant superoxide dismutase I (SOD1 in motor neurons is a pathological hallmark of some forms of the disease. We have shown that the orderly progression of the disease may be explained by misfolded SOD1 cell-to-cell propagation, which is reliant upon its active endogenous synthesis. Reducing the levels of SOD1 is therefore a promising therapeutic approach. Antisense oligonucleotides (ASOs can efficiently silence proteins with gain-of-function mutations. However, naked ASOs have a short circulation half-life and are unable to cross the blood brain barrier (BBB warranting the use of a drug carrier for effective delivery. In this study, calcium phosphate lipid coated nanoparticles (CaP-lipid NPs were developed for delivery of SOD1 ASO to motor neurons. The most promising nanoparticle formulation (Ca/P ratio of 100:1, had a uniform spherical core–shell morphology with an average size of 30 nm, and surface charge (ζ-potential of −4.86 mV. The encapsulation efficiency of ASO was 48% and stability studies found the particle to be stable over a period of 20 days. In vitro experiments demonstrated that the negatively charged ASO-loaded CaP-lipid NPs could effectively deliver SOD1-targeted ASO into a mouse motor neuron-like cell line (NSC-34 through endocytosis and significantly down-regulated SOD1 expression in HEK293 cells. The CaP-lipid NPs exhibited a pH-dependant dissociation, suggesting that that the acidification of lysosomes is the likely mechanism responsible for facilitating intracellular ASO release. To demonstrate tissue specific delivery and localization of these NPs we performed in vivo microinjections into zebrafish. Successful delivery of these NPs was confirmed for the zebrafish brain, the blood stream, and the spinal cord. These results suggest that Ca

  5. GLT-1-Dependent Disruption of CNS Glutamate Homeostasis and Neuronal Function by the Protozoan Parasite Toxoplasma gondii.

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    Clément N David

    2016-06-01

    Full Text Available The immune privileged nature of the CNS can make it vulnerable to chronic and latent infections. Little is known about the effects of lifelong brain infections, and thus inflammation, on the neurological health of the host. Toxoplasma gondii is a parasite that can infect any mammalian nucleated cell with average worldwide seroprevalence rates of 30%. Infection by Toxoplasma is characterized by the lifelong presence of parasitic cysts within neurons in the brain, requiring a competent immune system to prevent parasite reactivation and encephalitis. In the immunocompetent individual, Toxoplasma infection is largely asymptomatic, however many recent studies suggest a strong correlation with certain neurodegenerative and psychiatric disorders. Here, we demonstrate a significant reduction in the primary astrocytic glutamate transporter, GLT-1, following infection with Toxoplasma. Using microdialysis of the murine frontal cortex over the course of infection, a significant increase in extracellular concentrations of glutamate is observed. Consistent with glutamate dysregulation, analysis of neurons reveal changes in morphology including a reduction in dendritic spines, VGlut1 and NeuN immunoreactivity. Furthermore, behavioral testing and EEG recordings point to significant changes in neuronal output. Finally, these changes in neuronal connectivity are dependent on infection-induced downregulation of GLT-1 as treatment with the ß-lactam antibiotic ceftriaxone, rescues extracellular glutamate concentrations, neuronal pathology and function. Altogether, these data demonstrate that following an infection with T. gondii, the delicate regulation of glutamate by astrocytes is disrupted and accounts for a range of deficits observed in chronic infection.

  6. Long-Range Regulatory Synergy Is Required to Allow Control of the TAC1 Locus by MEK/ERK Signalling in Sensory Neurones

    Directory of Open Access Journals (Sweden)

    Lynne Shanley

    2010-12-01

    Full Text Available Changes in the expression of the neuropeptide substance P (SP in different populations of sensory neurones are associated with the progression of chronic inflammatory disease. Thus, understanding the genomic and cellular mechanisms driving the expression of the TAC1 gene, which encodes SP, in sensory neurones is essential to understanding its role in inflammatory disease. We used a novel combination of computational genomics, primary-cell culture and mouse transgenics to determine the genomic and cellular mechanisms that control the expression of TAC1 in sensory neurones. Intriguingly, we demonstrated that the promoter of the TAC1 gene must act in synergy with a remote enhancer, identified using comparative genomics, to respond to MAPK signalling that modulates the expression of TAC1 in sensory neurones. We also reveal that noxious stimulation of sensory neurones triggers this synergy in larger diameter sensory neurones – an expression of SP associated with hyperalgesia. This noxious stimulation of TAC1 enhancer-promotor synergy could be strongly blocked by antagonism of the MEK pathway. This study provides a unique insight into the role of long-range enhancer-promoter synergy and selectivity in the tissue-specific response of promoters to specific signal transduction pathways and suggests a possible new avenue for the development of novel anti-inflammatory therapies.

  7. Selective serotonergic excitation of callosal projection neurons

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    Daniel eAvesar

    2012-03-01

    Full Text Available Serotonin (5-HT acting as a neurotransmitter in the cerebral cortex is critical for cognitive function, yet how 5-HT regulates information processing in cortical circuits is not well understood. We tested the serotonergic responsiveness of layer 5 pyramidal neurons (L5PNs of the mouse medial prefrontal cortex (mPFC, and found 3 distinct response types: long-lasting 5-HT1A (1A receptor-dependent inhibitory responses (84% of L5PNs, 5-HT2A (2A receptor-dependent excitatory responses (9%, and biphasic responses in which 2A-dependent excitation followed brief inhibition (5%. Relative to 5-HT-inhibited neurons, those excited by 5-HT had physiological properties characteristic of callosal/commissural (COM neurons that project to the contralateral cortex. We tested whether serotonergic responses in cortical pyramidal neurons are correlated with their axonal projection pattern using retrograde fluorescent labeling of COM and corticopontine-projecting (CPn neurons. 5-HT generated excitatory or biphasic responses in all 5-HT-responsive layer 5 COM neurons. Conversely, CPn neurons were universally inhibited by 5-HT. Serotonergic excitation of COM neurons was blocked by the 2A antagonist MDL 11939, while serotonergic inhibition of CPn neurons was blocked by the 1A antagonist WAY 100635, confirming a role for these two receptor subtypes in regulating pyramidal neuron activity. Selective serotonergic excitation of COM neurons was not layer-specific, as COM neurons in layer 2/3 were also selectively excited by 5-HT relative to their non-labeled pyramidal neuron neighbors. Because neocortical 2A receptors are implicated in the etiology and pathophysiology of schizophrenia, we propose that COM neurons may represent a novel cellular target for intervention in psychiatric disease.

  8. Long-term activation of group I metabotropic glutamate receptors increases functional TRPV1-expressing neurons in mouse dorsal root ganglia

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    Takayoshi eMasuoka

    2016-03-01

    Full Text Available Damaged tissues release glutamate and other chemical mediators for several hours. These chemical mediators contribute to modulation of pruritus and pain. Herein, we investigated the effects of long-term activation of excitatory glutamate receptors on functional expression of transient receptor potential vaniloid type 1 (TRPV1 in dorsal root ganglion (DRG neurons and then on thermal pain behavior. In order to detect the TRPV1-mediated responses in cultured DRG neurons, we monitored intracellular calcium responses to capsaicin, a TRPV1 agonist, with Fura-2. Long-term (4 h treatment with glutamate receptor agonists (glutamate, quisqualate or DHPG increased the proportion of neurons responding to capsaicin through activation of metabotropic glutamate receptor mGluR1, and only partially through the activation of mGluR5; engagement of these receptors was evident in neurons responding to allylisothiocyanate (AITC, a transient receptor potential ankyrin type 1 (TRPA1 agonist. Increase in the proportion was suppressed by phospholipase C, protein kinase C, mitogen/extracellular signal-regulated kinase, p38 mitogen-activated protein kinase or transcription inhibitors. Whole-cell recording was performed to record TRPV1-mediated membrane current; TRPV1 current density significantly increased in the AITC-sensitive neurons after the quisqualate treatment. To elucidate the physiological significance of this phenomenon, a hot plate test was performed. Intraplantar injection of quisqualate or DHPG induced heat hyperalgesia that lasted for 4 h post injection. This chronic hyperalgesia was attenuated by treatment with either mGluR1 or mGluR5 antagonists. These results suggest that long-term activation of mGluR1/5 by peripherally released glutamate may increase the number of neurons expressing functional TRPV1 in DRG, which may be strongly associated with chronic hyperalgesia.

  9. Determination of the rate constant for neuronal and extra-neuronal monoamine oxidase

    International Nuclear Information System (INIS)

    Cassis, L.; Ludwig, J.; Trendelenburg, U.

    1986-01-01

    In the rat vas deferens, neuronal deamination of 3 H-(-) noradrenaline ( 3 H-NA) to 3 H-dihydroxyphenethylglycol ( 3 HDOPEG) cannot be inhibited by pretreatment with a monoamine oxidase (MAO) inhibitor. However, in the extraneuronal compartment of the rat heart, inhibition of MAO abolishes the formation of 3 HDOPEG. To clarify this discrepancy, the authors determined the rate constant for MAO (/sup k/mao/) neuronally (rat vas deferens) and extraneuronally (rat heart). For neuronal /sup k/mao, vasa deferentia were incubated with 3 HNA for 300 minutes, and the cumulative formation of 3 HDOPEG measured. The delay in time before 3 HDOPEG achieves steady state (/sup tau/system), is inversely proportional to /sup k/mao. Because /sup tau/system is very short for neuronal MAO, an appreciable delay was only achieved after partial inhibition of MAO with various parglyline concentrations. To relate to the uninhibited enzyme, the percentage inhibition by pargyline was then determined in homogenate preparations. For extraneuronal MAO, a similar procedure was performed in perfused rat hearts. Results show a significantly greater /sup k/mao of neuronal origin, (/sup k/mao = .57min - 1) which when related to the fractional size of the neuronal compartment suggests a very high activity of neuronal MAO

  10. Interleukin-6 Deficiency Does Not Affect Motor Neuron Disease Caused by Superoxide Dismutase 1 Mutation.

    Science.gov (United States)

    Han, Yongmei; Ripley, Barry; Serada, Satoshi; Naka, Tetsuji; Fujimoto, Minoru

    2016-01-01

    Amyotrophic Lateral Sclerosis (ALS) is an adult-onset, progressive, motor neuron degenerative disease. Recent evidence indicates that inflammation is associated with many neurodegenerative diseases including ALS. Previously, abnormal levels of inflammatory cytokines including IL-1β, IL-6 and TNF-α were described in ALS patients and/or in mouse ALS models. In addition, one study showed that blocking IL-1β could slow down progression of ALS-like symptoms in mice. In this study, we examined a role for IL-6 in ALS, using an animal model for familial ALS. Mice with mutant SOD1 (G93A) transgene, a model for familial ALS, were used in this study. The expression of the major inflammatory cytokines, IL-6, IL-1β and TNF-α, in spinal cords of these SOD1 transgenic (TG) mice were assessed by real time PCR. Mice were then crossed with IL-6(-/-) mice to generate SOD1TG/IL-6(-/-) mice. SOD1 TG/IL-6(-/-) mice (n = 17) were compared with SOD1 TG/IL-6(+/-) mice (n = 18), SOD1 TG/IL-6(+/+) mice (n = 11), WT mice (n = 15), IL-6(+/-) mice (n = 5) and IL-6(-/-) mice (n = 8), with respect to neurological disease severity score, body weight and the survival. We also histologically compared the motor neuron loss in lumber spinal cords and the atrophy of hamstring muscles between these mouse groups. Levels of IL-6, IL-1β and TNF-α in spinal cords of SOD1 TG mice was increased compared to WT mice. However, SOD1 TG/IL-6(-/-) mice exhibited weight loss, deterioration in motor function and shortened lifespan (167.55 ± 11.52 days), similarly to SOD1 TG /IL-6(+/+) mice (164.31±12.16 days). Motor neuron numbers and IL-1β and TNF-α levels in spinal cords were not significantly different in SOD1 TG /IL-6(-/-) mice and SOD1 TG /IL-6 (+/+) mice. These results provide compelling preclinical evidence indicating that IL-6 does not directly contribute to motor neuron disease caused by SOD1 mutations.

  11. Interleukin-6 Deficiency Does Not Affect Motor Neuron Disease Caused by Superoxide Dismutase 1 Mutation.

    Directory of Open Access Journals (Sweden)

    Yongmei Han

    Full Text Available Amyotrophic Lateral Sclerosis (ALS is an adult-onset, progressive, motor neuron degenerative disease. Recent evidence indicates that inflammation is associated with many neurodegenerative diseases including ALS. Previously, abnormal levels of inflammatory cytokines including IL-1β, IL-6 and TNF-α were described in ALS patients and/or in mouse ALS models. In addition, one study showed that blocking IL-1β could slow down progression of ALS-like symptoms in mice. In this study, we examined a role for IL-6 in ALS, using an animal model for familial ALS.Mice with mutant SOD1 (G93A transgene, a model for familial ALS, were used in this study. The expression of the major inflammatory cytokines, IL-6, IL-1β and TNF-α, in spinal cords of these SOD1 transgenic (TG mice were assessed by real time PCR. Mice were then crossed with IL-6(-/- mice to generate SOD1TG/IL-6(-/- mice. SOD1 TG/IL-6(-/- mice (n = 17 were compared with SOD1 TG/IL-6(+/- mice (n = 18, SOD1 TG/IL-6(+/+ mice (n = 11, WT mice (n = 15, IL-6(+/- mice (n = 5 and IL-6(-/- mice (n = 8, with respect to neurological disease severity score, body weight and the survival. We also histologically compared the motor neuron loss in lumber spinal cords and the atrophy of hamstring muscles between these mouse groups.Levels of IL-6, IL-1β and TNF-α in spinal cords of SOD1 TG mice was increased compared to WT mice. However, SOD1 TG/IL-6(-/- mice exhibited weight loss, deterioration in motor function and shortened lifespan (167.55 ± 11.52 days, similarly to SOD1 TG /IL-6(+/+ mice (164.31±12.16 days. Motor neuron numbers and IL-1β and TNF-α levels in spinal cords were not significantly different in SOD1 TG /IL-6(-/- mice and SOD1 TG /IL-6 (+/+ mice.These results provide compelling preclinical evidence indicating that IL-6 does not directly contribute to motor neuron disease caused by SOD1 mutations.

  12. Statistics of Visual Responses to Image Object Stimuli from Primate AIT Neurons to DNN Neurons.

    Science.gov (United States)

    Dong, Qiulei; Wang, Hong; Hu, Zhanyi

    2018-02-01

    Under the goal-driven paradigm, Yamins et al. ( 2014 ; Yamins & DiCarlo, 2016 ) have shown that by optimizing only the final eight-way categorization performance of a four-layer hierarchical network, not only can its top output layer quantitatively predict IT neuron responses but its penultimate layer can also automatically predict V4 neuron responses. Currently, deep neural networks (DNNs) in the field of computer vision have reached image object categorization performance comparable to that of human beings on ImageNet, a data set that contains 1.3 million training images of 1000 categories. We explore whether the DNN neurons (units in DNNs) possess image object representational statistics similar to monkey IT neurons, particularly when the network becomes deeper and the number of image categories becomes larger, using VGG19, a typical and widely used deep network of 19 layers in the computer vision field. Following Lehky, Kiani, Esteky, and Tanaka ( 2011 , 2014 ), where the response statistics of 674 IT neurons to 806 image stimuli are analyzed using three measures (kurtosis, Pareto tail index, and intrinsic dimensionality), we investigate the three issues in this letter using the same three measures: (1) the similarities and differences of the neural response statistics between VGG19 and primate IT cortex, (2) the variation trends of the response statistics of VGG19 neurons at different layers from low to high, and (3) the variation trends of the response statistics of VGG19 neurons when the numbers of stimuli and neurons increase. We find that the response statistics on both single-neuron selectivity and population sparseness of VGG19 neurons are fundamentally different from those of IT neurons in most cases; by increasing the number of neurons in different layers and the number of stimuli, the response statistics of neurons at different layers from low to high do not substantially change; and the estimated intrinsic dimensionality values at the low

  13. Histamine influences body temperature by acting at H1 and H3 receptors on distinct populations of preoptic neurons.

    Science.gov (United States)

    Lundius, Ebba Gregorsson; Sanchez-Alavez, Manuel; Ghochani, Yasmin; Klaus, Joseph; Tabarean, Iustin V

    2010-03-24

    The preoptic area/anterior hypothalamus, a region that contains neurons that control thermoregulation, is the main locus at which histamine affects body temperature. Here we report that histamine reduced the spontaneous firing rate of GABAergic preoptic neurons by activating H3 subtype histamine receptors. This effect involved a decrease in the level of phosphorylation of the extracellular signal-regulated kinase and was not dependent on synaptic activity. Furthermore, a population of non-GABAergic neurons was depolarized, and their firing rate was enhanced by histamine acting at H1 subtype receptors. In our experiments, activation of the H1R receptors was linked to the PLC pathway and Ca(2+) release from intracellular stores. This depolarization persisted in TTX or when fast synaptic potentials were blocked, indicating that it represents a postsynaptic effect. Single-cell reverse transcription-PCR analysis revealed expression of H3 receptors in a population of GABAergic neurons, while H1 receptors were expressed in non-GABAergic cells. Histamine applied in the median preoptic nucleus induced a robust, long-lasting hyperthermia effect that was mimicked by either H1 or H3 histamine receptor subtype-specific agonists. Our data indicate that histamine modulates the core body temperature by acting at two distinct populations of preoptic neurons that express H1 and H3 receptor subtypes, respectively.

  14. Kappe neurons, a novel population of olfactory sensory neurons

    OpenAIRE

    Ahuja, Gaurav; Nia, Shahrzad Bozorg; Zapilko, Veronika; Shiriagin, Vladimir; Kowatschew, Daniel; Oka, Yuichiro; Korsching, Sigrun I.

    2014-01-01

    Perception of olfactory stimuli is mediated by distinct populations of olfactory sensory neurons, each with a characteristic set of morphological as well as functional parameters. Beyond two large populations of ciliated and microvillous neurons, a third population, crypt neurons, has been identified in teleost and cartilaginous fishes. We report here a novel, fourth olfactory sensory neuron population in zebrafish, which we named kappe neurons for their characteristic shape. Kappe neurons ar...

  15. αν and β1 Integrins mediate Aβ-induced neurotoxicity in hippocampal neurons via the FAK signaling pathway.

    Directory of Open Access Journals (Sweden)

    Hai-Yan Han

    Full Text Available αν and β1 integrins mediate Aβ-induced neurotoxicity in primary hippocampal neurons. We treated hippocampal neurons with 2.5 µg/mL 17E6 and 5 µg/mL ab58524, which are specific αν and β1 integrin antagonists, respectively, for 42 h prior to 10 µM Aβ treatment. Next, we employed small interfering RNA (siRNA to silence focal adhesion kinase (FAK, a downstream target gene of integrins. The siRNAs were designed with a target sequence, an MOI of 10 and the addition of 5 µg/mL polybrene. Under these conditions, the neurons were transfected and the apoptosis of different cell types was detected. Moreover, we used real-time PCR and Western blotting analyses to detect the expression of FAK and ρFAK genes in different cell types and investigated the underlying mechanism and signal pathway by which αν and β1 integrins mediate Aβ-induced neurotoxicity in hippocampal neurons. An MTT assay showed that both 17E6 and ab58524 significantly increased cell viability compared with the Aβ-treated neurons (P<0.01 and P<0.05, respectively. However, this protective effect was markedly attenuated after transfection with silencing FAK (siFAK. Moreover, TUNEL immunostaining and flow cytometry indicated that both 17E6 and ab58524 significantly protected hippocampal neurons against apoptosis induced by Aβ (P<0.05 compared with the Aβ-treated cells. However, this protective effect was reversed with siFAK treatment. Both the gene and protein expression of FAK increased after Aβ treatment. Interestingly, as the gene and protein levels of FAK decreased, the ρFAK protein expression markedly increased. Furthermore, both the gene and protein expression of FAK and ρFAK were significantly diminished. Thus, we concluded that both αν and β1 integrins interfered with Aβ-induced neurotoxicity in hippocampal neurons and that this mechanism partially contributes to the activation of the Integrin-FAK signaling pathway.

  16. Role of hippocampal dentate gyrus neurons in the protective effects of heat shock factor 1 on working memory

    Institute of Scientific and Technical Information of China (English)

    Min Peng; Xiongzhao Zhu; Ming Cheng; Xiangyi Chen; Shuqiao Yao

    2011-01-01

    Increasing evidence suggests that heat shock factor 1 exerts endogenous protective effects on working memory under conditions of chronic psychological stress. However, the precise underlying mechanisms remain poorly understood. This study examined the protective factors affecting working memory in heat shock transcription factor 1 gene knockout mice. The results indicated that the number of correct T maze alternations decreased following mild chronic psychological stress in knockout mice. This change was accompanied by a decrease in neurogenesis and an increase in neuronal apoptosis in the hippocampal dentate gyrus. The number of correct T maze alternations was positively correlated with neurogenesis in hippocampal dentate gyrus, and negatively correlated with neuronal apoptosis. In wild type mice, no significant difference was detected in the number of correct T maze alternations or neuronal apoptosis in hippocampal dentate gyrus. These results indicate that the heat shock factor 1 gene has an endogenous protective role in working memory during mild chronic psychological stress associated with dentate gyrus neuronal apoptosis.Moreover, dentate gyrus neurogenesis appears to participate in the protective mechanism.

  17. SFPQ associates to LSD1 and regulates the migration of newborn pyramidal neurons in the developing cerebral cortex.

    Science.gov (United States)

    Saud, K; Cánovas, J; Lopez, C I; Berndt, F A; López, E; Maass, J C; Barriga, A; Kukuljan, M

    2017-04-01

    The development of the cerebral cortex requires the coordination of multiple processes ranging from the proliferation of progenitors to the migration and establishment of connectivity of the newborn neurons. Epigenetic regulation carried out by the COREST/LSD1 complex has been identified as a mechanism that regulates the development of pyramidal neurons of the cerebral cortex. We now identify the association of the multifunctional RNA-binding protein SFPQ to LSD1 during the development of the cerebral cortex. In vivo reduction of SFPQ dosage by in utero electroporation of a shRNA results in impaired radial migration of newborn pyramidal neurons, in a similar way to that observed when COREST or LSD1 expressions are decreased. Diminished SFPQ expression also associates to decreased proliferation of progenitor cells, while it does not affect the acquisition of neuronal fate. These results are compatible with the idea that SFPQ, plays an important role regulating proliferation and migration during the development of the cerebral cortex. Copyright © 2016 ISDN. Published by Elsevier Ltd. All rights reserved.

  18. Tet1 Oxidase Regulates Neuronal Gene Transcription, Active DNA Hydroxy-methylation, Object Location Memory, and Threat Recognition Memory.

    Science.gov (United States)

    Kumar, Dinesh; Aggarwal, Milan; Kaas, Garrett A; Lewis, John; Wang, Jing; Ross, Daniel L; Zhong, Chun; Kennedy, Andrew; Song, Hongjun; Sweatt, J David

    2015-10-01

    A dynamic equilibrium between DNA methylation and demethylation of neuronal activity-regulated genes is crucial for memory processes. However, the mechanisms underlying this equilibrium remain elusive. Tet1 oxidase has been shown to play a key role in the active DNA demethylation in the CNS. In this study, we used Tet1 gene knockout (Tet1KO) mice to examine the involvement of Tet1 in memory consolidation and storage in the adult brain. We found that Tet1 ablation leads to: altered expression of numerous neuronal activity-regulated genes, compensatory upregulation of active demethylation pathway genes, and upregulation of various epigenetic modifiers. Moreover, Tet1KO mice showed an enhancement in the consolidation and storage of threat recognition (cued and contextual fear conditioning) and object location memories. We conclude that Tet1 plays a critical role in regulating neuronal transcription and in maintaining the epigenetic state of the brain associated with memory consolidation and storage.

  19. Attenuation of hypoxic current by intracellular applications of ATP regenerating agents in hippocampal CA1 neurons of rat brain slices.

    Science.gov (United States)

    Chung, I; Zhang, Y; Eubanks, J H; Zhang, L

    1998-10-01

    Hypoxia-induced outward currents (hyperpolarization) were examined in hippocampal CA1 neurons of rat brain slices, using the whole-cell recording technique. Hypoxic episodes were induced by perfusing slices with an artificial cerebrospinal fluid aerated with 5% CO2/95% N2 rather than 5% CO2/95% O2, for about 3 min. The hypoxic current was consistently and reproducibly induced in CA1 neurons dialysed with an ATP-free patch pipette solution. This current manifested as an outward shift in the holding current in association with increased conductance, and it reversed at -78 +/- 2.5 mV, with a linear I-V relation in the range of -100 to -40 mV. To provide extra energy resources to individual neurons recorded, agents were added to the patch pipette solution, including MgATP alone, MgATP + phosphocreatine + creatine kinase, or MgATP + creatine. In CA1 neurons dialysed with patch solutions including these agents, hypoxia produced small outward currents in comparison with those observed in CA1 neurons dialysed with the ATP-free solution. Among the above agents examined, whole-cell dialysis with MgATP + creatine was the most effective at decreasing the hypoxic outward currents. We suggest that the hypoxic hyperpolarization is closely related to energy metabolism in individual CA1 neurons, and that the energy supply provided by phosphocreatine metabolism may play a critical role during transient metabolic stress.

  20. cAMP-dependent cell differentiation triggered by activated CRHR1 in hippocampal neuronal cells.

    Science.gov (United States)

    Inda, Carolina; Bonfiglio, Juan José; Dos Santos Claro, Paula A; Senin, Sergio A; Armando, Natalia G; Deussing, Jan M; Silberstein, Susana

    2017-05-16

    Corticotropin-releasing hormone receptor 1 (CRHR1) activates the atypical soluble adenylyl cyclase (sAC) in addition to transmembrane adenylyl cyclases (tmACs). Both cAMP sources were shown to be required for the phosphorylation of ERK1/2 triggered by activated G protein coupled receptor (GPCR) CRHR1 in neuronal and neuroendocrine contexts. Here, we show that activated CRHR1 promotes growth arrest and neurite elongation in neuronal hippocampal cells (HT22-CRHR1 cells). By characterising CRHR1 signalling mechanisms involved in the neuritogenic effect, we demonstrate that neurite outgrowth in HT22-CRHR1 cells takes place by a sAC-dependent, ERK1/2-independent signalling cascade. Both tmACs and sAC are involved in corticotropin-releasing hormone (CRH)-mediated CREB phosphorylation and c-fos induction, but only sAC-generated cAMP pools are critical for the neuritogenic effect of CRH, further highlighting the engagement of two sources of cAMP downstream of the activation of a GPCR, and reinforcing the notion that restricted cAMP microdomains may regulate independent cellular processes.

  1. Regulation of Na(+)/K(+)-ATPase by neuron-specific transcription factor Sp4: implication in the tight coupling of energy production, neuronal activity and energy consumption in neurons.

    Science.gov (United States)

    Johar, Kaid; Priya, Anusha; Wong-Riley, Margaret T T

    2014-02-01

    A major source of energy demand in neurons is the Na(+)/K(+)-ATPase pump that restores the ionic gradient across the plasma membrane subsequent to depolarizing neuronal activity. The energy comes primarily from mitochondrial oxidative metabolism, of which cytochrome c oxidase (COX) is a key enzyme. Recently, we found that all 13 subunits of COX are regulated by specificity (Sp) factors, and that the neuron-specific Sp4, but not Sp1 or Sp3, regulates the expression of key glutamatergic receptor subunits as well. The present study sought to test our hypothesis that Sp4 also regulates Na(+)/K(+)-ATPase subunit genes in neurons. By means of multiple approaches, including in silico analysis, electrophoretic mobility shift and supershift assays, chromatin immunoprecipitation, promoter mutational analysis, over-expression, and RNA interference studies, we found that Sp4, with minor contributions from Sp1 and Sp3, functionally regulate the Atp1a1, Atp1a3, and Atp1b1 subunit genes of Na(+)/K(+)-ATPase in neurons. Transcripts of all three genes were up-regulated by depolarizing KCl stimulation and down-regulated by the impulse blocker tetrodotoxin (TTX), indicating that their expression was activity-dependent. Silencing of Sp4 blocked the up-regulation of these genes induced by KCl, whereas over-expression of Sp4 rescued them from TTX-induced suppression. The effect of silencing or over-expressing Sp4 on primary neurons was much greater than those of Sp1 or Sp3. The binding sites of Sp factors on these genes are conserved among mice, rats and humans. Thus, Sp4 plays an important role in the transcriptional coupling of energy generation and energy consumption in neurons. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  2. Neurons of self-defence: neuronal innervation of the exocrine defence glands in stick insects.

    Science.gov (United States)

    Stolz, Konrad; von Bredow, Christoph-Rüdiger; von Bredow, Yvette M; Lakes-Harlan, Reinhard; Trenczek, Tina E; Strauß, Johannes

    2015-01-01

    Stick insects (Phasmatodea) use repellent chemical substances (allomones) for defence which are released from so-called defence glands in the prothorax. These glands differ in size between species, and are under neuronal control from the CNS. The detailed neural innervation and possible differences between species are not studied so far. Using axonal tracing, the neuronal innervation is investigated comparing four species. The aim is to document the complexity of defence gland innervation in peripheral nerves and central motoneurons in stick insects. In the species studied here, the defence gland is innervated by the intersegmental nerve complex (ISN) which is formed by three nerves from the prothoracic (T1) and suboesophageal ganglion (SOG), as well as a distinct suboesophageal nerve (Nervus anterior of the suboesophageal ganglion). In Carausius morosus and Sipyloidea sipylus, axonal tracing confirmed an innervation of the defence glands by this N. anterior SOG as well as N. anterior T1 and N. posterior SOG from the intersegmental nerve complex. In Peruphasma schultei, which has rather large defence glands, only the innervation by the N. anterior SOG was documented by axonal tracing. In the central nervous system of all species, 3-4 neuron types are identified by axonal tracing which send axons in the N. anterior SOG likely innervating the defence gland as well as adjacent muscles. These neurons are mainly suboesophageal neurons with one intersegmental neuron located in the prothoracic ganglion. The neuron types are conserved in the species studied, but the combination of neuron types is not identical. In addition, the central nervous system in S. sipylus contains one suboesophageal and one prothoracic neuron type with axons in the intersegmental nerve complex contacting the defence gland. Axonal tracing shows a very complex innervation pattern of the defence glands of Phasmatodea which contains different neurons in different nerves from two adjacent body segments

  3. Red nucleus and rubrospinal tract disorganization in the absence of Pou4f1

    Science.gov (United States)

    Martinez-Lopez, Jesus E.; Moreno-Bravo, Juan A.; Madrigal, M. Pilar; Martinez, Salvador; Puelles, Eduardo

    2015-01-01

    The red nucleus (RN) is a neuronal population that plays an important role in forelimb motor control and locomotion. Histologically it is subdivided into two subpopulations, the parvocellular RN (pRN) located in the diencephalon and the magnocellular RN (mRN) in the mesencephalon. The RN integrates signals from motor cortex and cerebellum and projects to spinal cord interneurons and motor neurons through the rubrospinal tract (RST). Pou4f1 is a transcription factor highly expressed in this nucleus that has been related to its specification. Here we profoundly analyzed consequences of Pou4f1 loss-of-function in development, maturation and axonal projection of the RN. Surprisingly, RN neurons are specified and maintained in the mutant, no cell death was detected. Nevertheless, the nucleus appeared disorganized with a strong delay in radial migration and with a wider neuronal distribution; the neurons did not form a compacted population as they do in controls, Robo1 and Slit2 were miss-expressed. Cplx1 and Npas1, expressed in the RN, are transcription factors involved in neurotransmitter release, neuronal maturation and motor function processes among others. In our mutant mice, both transcription factors are lost, suggesting an abnormal maturation of the RN. The resulting altered nucleus occupied a wider territory. Finally, we examined RST development and found that the RN neurons were able to project to the spinal cord but their axons appeared defasciculated. These data suggest that Pou4f1 is necessary for the maturation of RN neurons but not for their specification and maintenance. PMID:25698939

  4. Kv2 Ion Channels Determine the Expression and Localization of the Associated AMIGO-1 Cell Adhesion Molecule in Adult Brain Neurons

    Directory of Open Access Journals (Sweden)

    Hannah I. Bishop

    2018-01-01

    Full Text Available Voltage-gated K+ (Kv channels play important roles in regulating neuronal excitability. Kv channels comprise four principal α subunits, and transmembrane and/or cytoplasmic auxiliary subunits that modify diverse aspects of channel function. AMIGO-1, which mediates homophilic cell adhesion underlying neurite outgrowth and fasciculation during development, has recently been shown to be an auxiliary subunit of adult brain Kv2.1-containing Kv channels. We show that AMIGO-1 is extensively colocalized with both Kv2.1 and its paralog Kv2.2 in brain neurons across diverse mammals, and that in adult brain, there is no apparent population of AMIGO-1 outside of that colocalized with these Kv2 α subunits. AMIGO-1 is coclustered with Kv2 α subunits at specific plasma membrane (PM sites associated with hypolemmal subsurface cisternae at neuronal ER:PM junctions. This distinct PM clustering of AMIGO-1 is not observed in brain neurons of mice lacking Kv2 α subunit expression. Moreover, in heterologous cells, coexpression of either Kv2.1 or Kv2.2 is sufficient to drive clustering of the otherwise uniformly expressed AMIGO-1. Kv2 α subunit coexpression also increases biosynthetic intracellular trafficking and PM expression of AMIGO-1 in heterologous cells, and analyses of Kv2.1 and Kv2.2 knockout mice show selective loss of AMIGO-1 expression and localization in neurons lacking the respective Kv2 α subunit. Together, these data suggest that in mammalian brain neurons, AMIGO-1 is exclusively associated with Kv2 α subunits, and that Kv2 α subunits are obligatory in determining the correct pattern of AMIGO-1 expression, PM trafficking and clustering.

  5. Recent behavioral history modifies coupling between cell activity and Arc gene transcription in hippocampal CA1 neurons.

    Science.gov (United States)

    Guzowski, John F; Miyashita, Teiko; Chawla, Monica K; Sanderson, Jennifer; Maes, Levi I; Houston, Frank P; Lipa, Peter; McNaughton, Bruce L; Worley, Paul F; Barnes, Carol A

    2006-01-24

    The ability of neurons to alter their transcriptional programs in response to synaptic input is of fundamental importance to the neuroplastic mechanisms underlying learning and memory. Because of technical limitations of conventional gene detection methods, the current view of activity-dependent neural transcription derives from experiments in which neurons are assumed quiescent until a signaling stimulus is given. The present study was designed to move beyond this static model by examining how earlier episodes of neural activity influence transcription of the immediate-early gene Arc. Using a sensitive FISH method that detects primary transcript at genomic alleles, the proportion of hippocampal CA1 neurons that activate transcription of Arc RNA was constant at approximately 40% in response to both a single novel exploration session and daily sessions repeated over 9 days. This proportion is similar to the percentage of active neurons defined electrophysiologically. However, this close correspondence was disrupted in rats exposed briefly, but repeatedly, to the same environment within a single day. Arc transcription in CA1 neurons declined dramatically after as few as four 5-min sessions, despite stable electrophysiological activity during all sessions. Additional experiments indicate that the decrement in Arc transcription occurred at the cellular, rather than synaptic level, and was not simply linked to habituation to novelty. Thus, the neural genomic response is governed by recent, but not remote, cell firing history in the behaving animal. This state-dependence of neuronal transcriptional coupling provides a mechanism of metaplasticity and may regulate capacity for synaptic modification in neural networks.

  6. Heteromeric ASIC channels composed of ASIC2b and ASIC1a display novel channel properties and contribute to acidosis-induced neuronal death

    Science.gov (United States)

    Sherwood, Thomas W.; Lee, Kirsten G.; Gormley, Matthew G.; Askwith, Candice C.

    2011-01-01

    Acid-sensing ion channel (ASIC) subunits associate to form homomeric or heteromeric proton-gated ion channels in neurons throughout the nervous system. The ASIC1a subunit plays an important role in establishing the kinetics of proton-gated currents in the central nervous system and activation of ASIC1a homomeric channels induces neuronal death following local acidosis that accompanies cerebral ischemia. The ASIC2b subunit is expressed in the brain in a pattern that overlaps ASIC1a, yet the contribution of ASIC2b has remained elusive. We find that co-expression of ASIC2b with ASIC1a in Xenopus oocytes results in novel proton-gated currents with properties distinct from ASIC1a homomeric channels. In particular, ASIC2b/1a heteromeric channels are inhibited by the non-selective potassium channel blockers tetraethylammonium (TEA) and barium. In addition, steady-state desensitization is induced at more basic pH values and Big Dynorphin sensitivity is enhanced in these unique heteromeric channels. Cultured hippocampal neurons show proton-gated currents consistent with ASIC2b contribution and these currents are lacking in neurons from mice with an ACCN1 (ASIC2) gene disruption. Finally, we find that these ASIC2b/1a heteromeric channels contribute to acidosis-induced neuronal death. Together, our results show that ASIC2b confers unique properties to heteromeric channels in central neurons. Further, these data indicate that ASIC2, like ASIC1, plays a role in acidosis-induced neuronal death and implicate the ASIC2b/1a subtype as a novel pharmacological target to prevent neuronal injury following stroke. PMID:21715637

  7. Anomaly-specified virtual dimensionality

    Science.gov (United States)

    Chen, Shih-Yu; Paylor, Drew; Chang, Chein-I.

    2013-09-01

    Virtual dimensionality (VD) has received considerable interest where VD is used to estimate the number of spectral distinct signatures, denoted by p. Unfortunately, no specific definition is provided by VD for what a spectrally distinct signature is. As a result, various types of spectral distinct signatures determine different values of VD. There is no one value-fit-all for VD. In order to address this issue this paper presents a new concept, referred to as anomaly-specified VD (AS-VD) which determines the number of anomalies of interest present in the data. Specifically, two types of anomaly detection algorithms are of particular interest, sample covariance matrix K-based anomaly detector developed by Reed and Yu, referred to as K-RXD and sample correlation matrix R-based RXD, referred to as R-RXD. Since K-RXD is only determined by 2nd order statistics compared to R-RXD which is specified by statistics of the first two orders including sample mean as the first order statistics, the values determined by K-RXD and R-RXD will be different. Experiments are conducted in comparison with widely used eigen-based approaches.

  8. Andrographolide Stimulates Neurogenesis in the Adult Hippocampus

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    Lorena Varela-Nallar

    2015-01-01

    Full Text Available Andrographolide (ANDRO is a labdane diterpenoid component of Andrographis paniculata widely used for its anti-inflammatory properties. We have recently determined that ANDRO is a competitive inhibitor of glycogen synthase kinase-3β (GSK-3β, a key enzyme of the Wnt/β-catenin signaling cascade. Since this signaling pathway regulates neurogenesis in the adult hippocampus, we evaluated whether ANDRO stimulates this process. Treatment with ANDRO increased neural progenitor cell proliferation and the number of immature neurons in the hippocampus of 2- and 10-month-old mice compared to age-matched control mice. Moreover, ANDRO stimulated neurogenesis increasing the number of newborn dentate granule neurons. Also, the effect of ANDRO was evaluated in the APPswe/PS1ΔE9 transgenic mouse model of Alzheimer’s disease. In these mice, ANDRO increased cell proliferation and the density of immature neurons in the dentate gyrus. Concomitantly with the increase in neurogenesis, ANDRO induced the activation of the Wnt signaling pathway in the hippocampus of wild-type and APPswe/PS1ΔE9 mice determined by increased levels of β-catenin, the inactive form of GSK-3β, and NeuroD1, a Wnt target gene involved in neurogenesis. Our findings indicate that ANDRO stimulates neurogenesis in the adult hippocampus suggesting that this drug could be used as a therapy in diseases in which neurogenesis is affected.

  9. 1,2-Dilinoleoyl-sn-glycero-3-phosphoethanolamine ameliorates age-related spatial memory deterioration by preventing neuronal cell death

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    Yaguchi Takahiro

    2010-09-01

    Full Text Available Abstract Background Accumulating evidence has pointed that a variety of lipids could exert their beneficial actions against dementia including Alzheimer disease and age-related cognitive decline via diverse signaling pathways. Endoplasmic reticulum (ER stress-induced neuronal apoptosis, on the other hand, is a critical factor for pathogenesis of neurodegenerative diseases such as Alzheimer disease and Parkinson disease, senile dementia, and ischemic neuronal damage. The present study examined the effects of 1,2-dilinoleoyl-sn-glycero-3-phosphoethanolamine (DLPhtEtn, a phospholipid, on ER stress-induced neuronal death and age-related cognitive disorders. Methods PC-12 cell viability was assayed before and after treatment with amyloid-β1-40 peptide or thapsigargin in the presence and absence of DLPhtEtn. A series of behavioral tests were performed for senescence-accelerated mouse-prone 8 (SAMP8 mice after 7-month oral administration with polyethylene glycol (PEG or DLPhtEtn and then, the number of hippocampal neurons was counted. Results Amyloid-β1-40 peptide or thapsigargin is capable of causing ER stress-induced apoptosis. DLPhtEtn (30 μM significantly inhibited PC-12 cell death induced by amyloid-β1-40 peptide or thapsigargin. In the water maze test, oral administration with DLPhtEtn (1 mg/kg for 7 months (three times a week significantly shortened the prolonged retention latency for SAMP8 mice. In contrast, DLPhtEtn had no effect on the acquisition and retention latencies in both the open field test and the passive avoidance test for SAMP8 mice. Oral administration with DLPhtEtn (1 mg/kg for 7 months prevented a decrease in the number of hippocampal neurons for SAMP8 mice. Conclusion The results of the present study show that DLPhtEtn ameliorates age-related spatial memory decline without affecting motor activities or fear memory, possibly by protecting hippocampal neuronal death. DLPhtEtn, thus, might exert its beneficial action against

  10. Insulin-like growth factor-1 prevents dorsal root ganglion neuronal tyrosine kinase receptor expression alterations induced by dideoxycytidine in vitro.

    Science.gov (United States)

    Liu, Huaxiang; Lu, Jing; He, Yong; Yuan, Bin; Li, Yizhao; Li, Xingfu

    2014-03-01

    Dideoxycytidine (zalcitabine, ddC) produces neurotoxic effects. It is particularly important to understand the toxic effects of ddC on different subpopulations of dorsal root ganglion (DRG) neurons which express distinct tyrosine kinase receptor (Trk) and to find therapeutic factors for prevention and therapy for ddC-induced peripheral sensory neuropathy. Insulin-like growth factor-1 (IGF-1) has been shown to have neurotrophic effects on DRG sensory neurons. However, little is known about the effects of ddC on distinct Trk (TrkA, TrkB, and TrkC) expression in DRG neurons and the neuroprotective effects of IGF-1 on ddC-induced neurotoxicity. Here, we have tested the extent to which the expression of TrkA, TrkB, and TrkC receptors in primary cultured DRG neurons is affected by ddC in the presence or absence of IGF-1. In this experiment, we found that exposure of 5, 25, and 50 μmol/L ddC caused a dose-dependent decrease of the mRNA, protein, and the proportion of TrkA-, TrkB-, and TrkC-expressing neurons. IGF-1 (20 nmol/L) could partially reverse the decrease of TrkA and TrkB, but not TrkC, expression with ddC exposure. The phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 (10 μmol/L) blocked the effects of IGF-1. These results suggested that the subpopulations of DRG neurons which express distinct TrkA, TrkB, and TrkC receptors were affected by ddC exposure. IGF-1 might relieve the ddC-induced toxicity of TrkA- and TrkB-, but not TrkC-expressing DRG neurons. These data offer new clues for a better understanding of the association of ddC with distinct Trk receptor expression and provide new evidence of the potential therapeutic role of IGF-1 on ddC-induced neurotoxicity.

  11. Reducing the Levels of Akt Activation by PDK1 Knock-in Mutation Protects Neuronal Cultures against Synthetic Amyloid-Beta Peptides

    Directory of Open Access Journals (Sweden)

    Shaobin Yang

    2018-01-01

    Full Text Available The Akt kinase has been widely assumed for years as a key downstream effector of the PI3K signaling pathway in promoting neuronal survival. This notion was however challenged by the finding that neuronal survival responses were still preserved in mice with reduced Akt activity. Moreover, here we show that the Akt signaling is elevated in the aged brain of two different mice models of Alzheimer Disease. We manipulate the rate of Akt stimulation by employing knock-in mice expressing a mutant form of PDK1 (phosphoinositide-dependent protein kinase 1 with reduced, but not abolished, ability to activate Akt. We found increased membrane localization and activity of the TACE/ADAM17 α-secretase in the brain of the PDK1 mutant mice with concomitant TNFR1 processing, which provided neurons with resistance against TNFα-induced neurotoxicity. Opposite to the Alzheimer Disease transgenic mice, the PDK1 knock-in mice exhibited an age-dependent attenuation of the unfolding protein response, which protected the mutant neurons against endoplasmic reticulum stressors. Moreover, these two mechanisms cooperatively provide the mutant neurons with resistance against amyloid-beta oligomers, and might singularly also contribute to protect these mice against amyloid-beta pathology.

  12. Enhanced IL-1beta production in response to the activation of hippocampal glial cells impairs neurogenesis in aged mice.

    Science.gov (United States)

    Kuzumaki, Naoko; Ikegami, Daigo; Imai, Satoshi; Narita, Michiko; Tamura, Rie; Yajima, Marie; Suzuki, Atsuo; Miyashita, Kazuhiko; Niikura, Keiichi; Takeshima, Hideyuki; Ando, Takayuki; Ushijima, Toshikazu; Suzuki, Tsutomu; Narita, Minoru

    2010-09-01

    A variety of mechanisms that contribute to the accumulation of age-related damage and the resulting brain dysfunction have been identified. Recently, decreased neurogenesis in the hippocampus has been recognized as one of the mechanisms of age-related brain dysfunction. However, the molecular mechanism of decreased neurogenesis with aging is still unclear. In the present study, we investigated whether aging decreases neurogenesis accompanied by the activation of microglia and astrocytes, which increases the expression of IL-1beta in the hippocampus, and whether in vitro treatment with IL-1beta in neural stem cells directly impairs neurogenesis. Ionized calcium-binding adaptor molecule 1 (Iba1)-positive microglia and glial fibrillary acidic protein (GFAP)-positive astrocytes were increased in the dentate gyrus of the hippocampus of 28-month-old mice. Furthermore, the mRNA level of IL-1beta was significantly increased without related histone modifications. Moreover, a significant increase in lysine 9 on histone H3 (H3K9) trimethylation at the promoter of NeuroD (a neural progenitor cell marker) was observed in the hippocampus of aged mice. In vitro treatment with IL-1beta in neural stem cells prepared from whole brain of E14.5 mice significantly increased H3K9 trimethylation at the NeuroD promoter. These findings suggest that aging may decrease hippocampal neurogenesis via epigenetic modifications accompanied by the activation of microglia and astrocytes with the increased expression of IL-1beta in the hippocampus.

  13. Pyramidal neurons in the septal and temporal CA1 field of the human and hedgehog tenrec hippocampus.

    Science.gov (United States)

    Liagkouras, Ioannis; Michaloudi, Helen; Batzios, Christos; Psaroulis, Dimitrios; Georgiadis, Marios; Künzle, Heinz; Papadopoulos, Georgios C

    2008-07-07

    The present study examines comparatively the cellular density of disector-counted/Nissl-stained CA1 pyramidal neurons and the morphometric characteristics (dendritic number/length, spine number/density and Sholl-counted dendritic branch points/20 microm) of the basal and apical dendritic systems of Golgi-impregnated CA1 neurons, in the septal and temporal hippocampus of the human and hedgehog tenrec brain. The obtained results indicate that in both hippocampal parts the cellular density of the CA1 pyramidal neurons is lower in human than in tenrec. However, while the human pyramidal cell density is higher in the septal hippocampal part than in the temporal one, in the tenrec the density of these cells is higher in the temporal part. The dendritic tree of the CA1 pyramidal cells, more developed in the septal than in temporal hippocampus in both species studied, is in general more complex in the human hippocampus. The basal and the apical dendritic systems exhibit species related morphometric differences, while dendrites of different orders exhibit differences in their number and length, and in their spine density. Finally, in both species, as well as hippocampal parts and dendritic systems, changes of dendritic morphometric features along ascending dendritic orders fluctuate in a similar way, as do the number of dendritic branch points in relation to the distance from the neuron soma.

  14. Contribution of large-sized primary sensory neuronal sensitization to mechanical allodynia by upregulation of hyperpolarization-activated cyclic nucleotide gated channels via cyclooxygenase 1 cascade.

    Science.gov (United States)

    Sun, Wei; Yang, Fei; Wang, Yan; Fu, Han; Yang, Yan; Li, Chun-Li; Wang, Xiao-Liang; Lin, Qing; Chen, Jun

    2017-02-01

    Under physiological state, small- and medium-sized dorsal root ganglia (DRG) neurons are believed to mediate nociceptive behavioral responses to painful stimuli. However, recently it has been found that a number of large-sized neurons are also involved in nociceptive transmission under neuropathic conditions. Nonetheless, the underlying mechanisms that large-sized DRG neurons mediate nociception are poorly understood. In the present study, the role of large-sized neurons in bee venom (BV)-induced mechanical allodynia and the underlying mechanisms were investigated. Behaviorally, it was found that mechanical allodynia was still evoked by BV injection in rats in which the transient receptor potential vanilloid 1-positive DRG neurons were chemically deleted. Electrophysiologically, in vitro patch clamp recordings of large-sized neurons showed hyperexcitability in these neurons. Interestingly, the firing pattern of these neurons was changed from phasic to tonic under BV-inflamed state. It has been suggested that hyperpolarization-activated cyclic nucleotide gated channels (HCN) expressed in large-sized DRG neurons contribute importantly to repeatedly firing. So we examined the roles of HCNs in BV-induced mechanical allodynia. Consistent with the overexpression of HCN1/2 detected by immunofluorescence, HCNs-mediated hyperpolarization activated cation current (I h ) was significantly increased in the BV treated samples. Pharmacological experiments demonstrated that the hyperexcitability and upregulation of I h in large-sized neurons were mediated by cyclooxygenase-1 (COX-1)-prostaglandin E2 pathway. This is evident by the fact that the COX-1 inhibitor significantly attenuated the BV-induced mechanical allodynia. These results suggest that BV can excite the large-sized DRG neurons at least in part by increasing I h through activation of COX-1. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Effects of VPAC1 activation in nucleus ambiguus neurons.

    Science.gov (United States)

    Gherghina, Florin Liviu; Tica, Andrei Adrian; Deliu, Elena; Abood, Mary E; Brailoiu, G Cristina; Brailoiu, Eugen

    2017-02-15

    The pituitary adenylyl cyclase-activating polypeptide (PACAP) and its G protein-coupled receptors, PAC1, VPAC1 and VPAC2 form a system involved in a variety of biological processes. Although some sympathetic stimulatory effects of this system have been reported, its central cardiovascular regulatory properties are poorly characterized. VPAC1 receptors are expressed in the nucleus ambiguus (nAmb), a key center controlling cardiac parasympathetic tone. In this study, we report that selective VPAC1 activation in rhodamine-labeled cardiac vagal preganglionic neurons of the rat nAmb produces inositol 1,4,5-trisphosphate receptor-mediated Ca 2+ mobilization, membrane depolarization and activation of P/Q-type Ca 2+ channels. In vivo, this pathway converges onto transient reduction in heart rate of conscious rats. Therefore we demonstrate a VPAC1-dependent mechanism in the central parasympathetic regulation of the heart rate, adding to the complexity of PACAP-mediated cardiovascular modulation. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Cytomorphometric changes in hippocampal CA1 neurons exposed to simulated microgravity using rats as model

    Directory of Open Access Journals (Sweden)

    Amit eRanjan

    2014-05-01

    Full Text Available Microgravity and sleep loss lead to cognitive and learning deficits. These behavioral alterations are likely to be associated with cytomorphological changes and loss of neurons. To understand the phenomenon, we exposed rats (225-275g to 14 days simulated microgravity (SMg and compared its effects on CA1 hippocampal neuronal plasticity, with that of normal cage control rats. We observed that the mean area, perimeter, synaptic cleft and length of active zone of CA1 hippocampal neurons significantly decreased while dendritic arborization and number of spines significantly increased in SMg group as compared with controls. The mean thickness of the post synaptic density and total dendritic length remained unaltered. The changes may be a compensatory effect induced by exposure to microgravity; however, the effects may be transient or permanent, which need further study. These findings may be useful for designing effective prevention for those, including the astronauts, exposed to microgravity. Further, subject to confirmation we propose that SMg exposure might be useful for recovery of stroke patients.

  17. Mitogen-activated protein kinase signaling pathways promote low-density lipoprotein receptor-related protein 1-mediated internalization of beta-amyloid protein in primary cortical neurons.

    Science.gov (United States)

    Yang, Wei-Na; Ma, Kai-Ge; Qian, Yi-Hua; Zhang, Jian-Shui; Feng, Gai-Feng; Shi, Li-Li; Zhang, Zhi-Chao; Liu, Zhao-Hui

    2015-07-01

    Mounting evidence suggests that the pathological hallmarks of Alzheimer's disease (AD) are caused by the intraneuronal accumulation of beta-amyloid protein (Aβ). Reuptake of extracellular Aβ is believed to contribute significantly to the intraneuronal Aβ pool in the early stages of AD. Published reports have claimed that the low-density lipoprotein receptor-related protein 1 (LRP1) mediates Aβ1-42 uptake and lysosomal trafficking in GT1-7 neuronal cells and mouse embryonic fibroblast non-neuronal cells. However, there is no direct evidence supporting the role of LRP1 in Aβ internalization in primary neurons. Our recent study indicated that p38 MAPK and ERK1/2 signaling pathways are involved in regulating α7 nicotinic acetylcholine receptor (α7nAChR)-mediated Aβ1-42 uptake in SH-SY5Y cells. This study was designed to explore the regulation of MAPK signaling pathways on LRP1-mediated Aβ internalization in neurons. We found that extracellular Aβ1-42 oligomers could be internalized into endosomes/lysosomes and mitochondria in cortical neurons. Aβ1-42 and LRP1 were also found co-localized in neurons during Aβ1-42 internalization, and they could form Aβ1-42-LRP1 complex. Knockdown of LRP1 expression significantly decreased neuronal1-42 internalization. Finally, we identified that p38 MAPK and ERK1/2 signaling pathways regulated the internalization of Aβ1-42 via LRP1. Therefore, these results demonstrated that LRP1, p38 MAPK and ERK1/2 mediated the internalization of Aβ1-42 in neurons and provided evidence that blockade of LRP1 or inhibitions of MAPK signaling pathways might be a potential approach to lowering brain Aβ levels and served a potential therapeutic target for AD. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Inhibiting the Activity of CA1 Hippocampal Neurons Prevents the Recall of Contextual Fear Memory in Inducible ArchT Transgenic Mice.

    Directory of Open Access Journals (Sweden)

    Masanori Sakaguchi

    Full Text Available The optogenetic manipulation of light-activated ion-channels/pumps (i.e., opsins can reversibly activate or suppress neuronal activity with precise temporal control. Therefore, optogenetic techniques hold great potential to establish causal relationships between specific neuronal circuits and their function in freely moving animals. Due to the critical role of the hippocampal CA1 region in memory function, we explored the possibility of targeting an inhibitory opsin, ArchT, to CA1 pyramidal neurons in mice. We established a transgenic mouse line in which tetracycline trans-activator induces ArchT expression. By crossing this line with a CaMKIIα-tTA transgenic line, the delivery of light via an implanted optrode inhibits the activity of excitatory CA1 neurons. We found that light delivery to the hippocampus inhibited the recall of a contextual fear memory. Our results demonstrate that this optogenetic mouse line can be used to investigate the neuronal circuits underlying behavior.

  19. Molecular basis of cellular localization of poly C binding protein 1 in neuronal cells

    International Nuclear Information System (INIS)

    Berry, Andrea M.; Flock, Kelly E.; Loh, Horace H.; Ko, Jane L.

    2006-01-01

    Poly C binding protein 1 (PCBP) is involved in the transcriptional regulation of neuronal mu-opioid receptor gene. In this study, we examined the molecular basis of PCBP cellular/nuclear localization in neuronal cells using EGFP fusion protein. PCBP, containing three KH domains and a variable domain, distributed in cytoplasm and nucleus with a preferential nuclear expression. Domain-deletional analyses suggested the requirement of variable and KH3 domains for strong PCBP nuclear expression. Within the nucleus, a low nucleolar PCBP expression was observed, and PCBP variable domain contributed to this restricted nucleolar expression. Furthermore, the punctate nuclear pattern of PCBP was correlated to its single-stranded (ss) DNA binding ability, with both requiring cooperativity of at least three sequential domains. Collectively, certain PCBP domains thus govern its nuclear distribution and transcriptional regulatory activity in the nucleus of neurons, whereas the low nucleolar expression implicates the disengagement of PCBP in the ribosomal RNA synthesis

  20. Neuronal low-density lipoprotein receptor-related protein 1 binds and endocytoses prion fibrils via receptor cluster 4

    DEFF Research Database (Denmark)

    Jen, Angela; Parkyn, Celia J; Mootoosamy, Roy C

    2010-01-01

    For infectious prion protein (designated PrP(Sc)) to act as a template to convert normal cellular protein (PrP(C)) to its distinctive pathogenic conformation, the two forms of prion protein (PrP) must interact closely. The neuronal receptor that rapidly endocytoses PrP(C) is the low......-density lipoprotein receptor-related protein 1 (LRP1). We show here that on sensory neurons LRP1 is also the receptor that binds and rapidly endocytoses smaller oligomeric forms of infectious prion fibrils, and recombinant PrP fibrils. Although LRP1 binds two molecules of most ligands independently to its receptor...... both prion and LRP1 biology....

  1. Glycemic state regulates melanocortin, but not nesfatin-1, responsiveness of glucose-sensing neurons in the nucleus of the solitary tract.

    Science.gov (United States)

    Mimee, Andrea; Ferguson, Alastair V

    2015-04-15

    The nucleus of the solitary tract (NTS) is a medullary integrative center with critical roles in the coordinated control of energy homeostasis. Here, we used whole cell current-clamp recordings on rat NTS neurons in slice preparation to identify the presence of physiologically relevant glucose-sensing neurons. The majority of NTS neurons (n = 81) were found to be glucose-responsive, with 35% exhibiting a glucose-excited (GE) phenotype (mean absolute change in membrane potential: 9.5 ± 1.1 mV), and 21% exhibiting a glucose-inhibited (GI) response (mean: 6.3 ± 0.7 mV). Furthermore, we found glucose-responsive cells are preferentially influenced by the anorexigenic peptide α-melanocyte-stimulating hormone (α-MSH), but not nesfatin-1. Accordingly, alterations in glycemic state have profound effects on the responsiveness of NTS neurons to α-MSH, but not to nesfatin-1. Indeed, NTS neurons showed increasing responsiveness to α-MSH as extracellular glucose concentrations were decreased, and in hypoglycemic conditions, all NTS neurons were depolarized by α-MSH (mean 10.6 ± 3.2 mV; n = 8). Finally, decreasing levels of extracellular glucose correlated with a significant hyperpolarization of the baseline membrane potential of NTS neurons, highlighting the modulatory effect of glucose on the baseline excitability of cells in this region. Our findings reveal individual NTS cells are capable of integrating multiple sources of metabolically relevant inputs, highlight the rapid capacity for plasticity in medullary melanocortin circuits, and emphasize the critical importance of physiological recording conditions for electrophysiological studies pertaining to the central control of energy homeostasis. Copyright © 2015 the American Physiological Society.

  2. Cardiac retention of PET neuronal imaging agent LMI1195 in different species: Impact of norepinephrine uptake-1 and -2 transporters

    International Nuclear Information System (INIS)

    Yu, Ming; Bozek, Jody; Kagan, Mikhail; Guaraldi, Mary; Silva, Paula; Azure, Michael; Onthank, David; Robinson, Simon P.

    2013-01-01

    Introduction: Released sympathetic neurotransmitter norepinephrine (NE) in the heart is cleared by neuronal uptake-1 and extraneuronal uptake-2 transporters. Cardiac uptake-1 and -2 expression varies among species, but the uptake-1 is the primary transporter in humans. LMI1195 is an NE analog labeled with 18 F for PET evaluation of cardiac neuronal function. This study investigated the impact of cardiac neuronal uptake-1 associated with different species on LMI1195 heart uptake. Methods: Cardiac uptake-1 was blocked by desipramine, a selective uptake-1 inhibitor, and sympathetic neuronal denervation was induced by 6-hydroxydopamine, a neurotoxin, in rats, rabbits and nonhuman primates (NHP). Tissue biodistribution and cardiac imaging of LMI1195 and 123 I-metaiodobenzylguanidine (MIBG) were performed. Results: In rats, uptake-1 blockade did not alter LMI1195 heart uptake compared to the control at 60-min post injection [1.41 ± 0.07 vs. 1.47 ± 0.23 % injected dose per gram tissue (%ID/g)]. In contrast, LMI1195 heart uptake was reduced by 80% in uptake-1 blocked rabbits. In sympathetically denervated rats, LMI1195 heart uptake was similar to the control (2.18 ± 0.40 vs. 2.58 ± 0.76 %ID/g). However, the uptake decreased by 79% in denervated rabbits. Similar results were found in MIBG heart uptake in rats and rabbits with uptake-1 blockade. Consistently, LMI1195 cardiac imaging showed comparable myocardial activity in uptake-1 blocked or sympathetically denervated rats to the control, but marked activity reduction in uptake-1 blocked or denervated rabbits and NHPs. Conclusions: LMI1195 is retained in the heart of rabbits and NHPs primarily via the neuronal uptake-1 with high selectivity and can be used for evaluation of cardiac sympathetic denervation. Similar to the human, the neuronal uptake-1 is the dominant transporter for cardiac retention of NE analogs in rabbits and NHPs, but not in rats

  3. Neuroprotective effects of a novel single compound 1-methoxyoctadecan-1-ol isolated from Uncaria sinensis in primary cortical neurons and a photothrombotic ischemia model.

    Directory of Open Access Journals (Sweden)

    Ji Yeon Jang

    Full Text Available We identified a novel neuroprotective compound, 1-methoxyoctadecan-1-ol, from Uncaria sinensis (Oliv. Havil and investigated its effects and mechanisms in primary cortical neurons and in a photothrombotic ischemic model. In primary rat cortical neurons against glutamate-induced neurotoxicity, pretreatment with 1-methoxyoctadecan-1-ol resulted in significantly reduced neuronal death in a dose-dependent manner. In addition, treatment with 1-methoxyoctadecan-1-ol resulted in decreased neuronal apoptotic death, as assessed by nuclear morphological approaches. To clarify the neuroprotective mechanism of 1-methoxyoctadecan-1-ol, we explored the downstream signaling pathways of N-methyl-D-aspartate receptor (NMDAR with calpain activation. Treatment with glutamate leads to early activation of NMDAR, which in turn leads to calpain-mediated cleavage of striatal-enriched protein tyrosine phosphatase (STEP and subsequent activation of p38 mitogen activated protein kinase (MAPK. However, pretreatment with 1-methoxyoctadecan-1-ol resulted in significantly attenuated activation of GluN2B-NMDAR and a decrease in calpain-mediated STEP cleavage, leading to subsequent attenuation of p38 MAPK activation. We confirmed the critical role of p38 MAPK in neuroprotective effects of 1-methoxyoctadecan-1-ol using specific inhibitor SB203580. In the photothrombotic ischemic injury in mice, treatment with 1-methoxyoctadecan-1-ol resulted in significantly reduced infarct volume, edema size, and improved neurological function. 1-methoxyoctadecan-1-ol effectively prevents cerebral ischemic damage through down-regulation of calpain-mediated STEP cleavage and activation of p38 MAPK. These results suggest that 1-methoxyoctadecan-1-ol showed neuroprotective effects through down-regulation of calpain-mediated STEP cleavage with activation of GluN2B-NMDAR, and subsequent alleviation of p38 MAPK activation. In addition, 1-methoxyoctadecan-1-ol might be a useful therapeutic agent for

  4. Cannabinoid receptor CB1 mediates baseline and activity-induced survival of new neurons in adult hippocampal neurogenesis

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    Müller Anke

    2010-06-01

    Full Text Available Abstract Background Adult neurogenesis is a particular example of brain plasticity that is partially modulated by the endocannabinoid system. Whereas the impact of synthetic cannabinoids on the neuronal progenitor cells has been described, there has been lack of information about the action of plant-derived extracts on neurogenesis. Therefore we here focused on the effects of Δ9-tetrahydrocannabinol (THC and Cannabidiol (CBD fed to female C57Bl/6 and Nestin-GFP-reporter mice on proliferation and maturation of neuronal progenitor cells and spatial learning performance. In addition we used cannabinoid receptor 1 (CB1 deficient mice and treatment with CB1 antagonist AM251 in Nestin-GFP-reporter mice to investigate the role of the CB1 receptor in adult neurogenesis in detail. Results THC and CBD differed in their effects on spatial learning and adult neurogenesis. CBD did not impair learning but increased adult neurogenesis, whereas THC reduced learning without affecting adult neurogenesis. We found the neurogenic effect of CBD to be dependent on the CB1 receptor, which is expressed over the whole dentate gyrus. Similarly, the neurogenic effect of environmental enrichment and voluntary wheel running depends on the presence of the CB1 receptor. We found that in the absence of CB1 receptors, cell proliferation was increased and neuronal differentiation reduced, which could be related to CB1 receptor mediated signaling in Doublecortin (DCX-expressing intermediate progenitor cells. Conclusion CB1 affected the stages of adult neurogenesis that involve intermediate highly proliferative progenitor cells and the survival and maturation of new neurons. The pro-neurogenic effects of CBD might explain some of the positive therapeutic features of CBD-based compounds.

  5. Chromatic detection from cone photoreceptors to V1 neurons to behavior in rhesus monkeys.

    Science.gov (United States)

    Hass, Charles A; Angueyra, Juan M; Lindbloom-Brown, Zachary; Rieke, Fred; Horwitz, Gregory D

    2015-01-01

    Chromatic sensitivity cannot exceed limits set by noise in the cone photoreceptors. To determine how close neurophysiological and psychophysical chromatic sensitivity come to these limits, we developed a parameter-free model of stimulus encoding in the cone outer segments, and we compared the sensitivity of the model to the psychophysical sensitivity of monkeys performing a detection task and to the sensitivity of individual V1 neurons. Modeled cones had a temporal impulse response and a noise power spectrum that were derived from in vitro recordings of macaque cones, and V1 recordings were made during performance of the detection task. The sensitivity of the simulated cone mosaic, the V1 neurons, and the monkeys were tightly yoked for low-spatiotemporal-frequency isoluminant modulations, indicating high-fidelity signal transmission for this class of stimuli. Under the conditions of our experiments and the assumptions for our model, the signal-to-noise ratio for these stimuli dropped by a factor of ∼3 between the cones and perception. Populations of weakly correlated V1 neurons narrowly exceeded the monkeys' chromatic sensitivity but fell well short of the cones' chromatic sensitivity, suggesting that most of the behavior-limiting noise lies between the cone outer segments and the output of V1. The sensitivity gap between the cones and behavior for achromatic stimuli was larger than for chromatic stimuli, indicating greater postreceptoral noise. The cone mosaic model provides a means to compare visual sensitivity across disparate stimuli and to identify sources of noise that limit visual sensitivity.

  6. IGF-1 delivery to CNS attenuates motor neuron cell death but does not improve motor function in type III SMA mice.

    Science.gov (United States)

    Tsai, Li-Kai; Chen, Yi-Chun; Cheng, Wei-Cheng; Ting, Chen-Hung; Dodge, James C; Hwu, Wuh-Liang; Cheng, Seng H; Passini, Marco A

    2012-01-01

    The efficacy of administering a recombinant adeno-associated virus (AAV) vector encoding human IGF-1 (AAV2/1-hIGF-1) into the deep cerebellar nucleus (DCN) of a type III SMA mouse model was evaluated. High levels of IGF-1 transcripts and protein were detected in the spinal cord at 2 months post-injection demonstrating that axonal connections between the cerebellum and spinal cord were able to act as conduits for the viral vector and protein to the spinal cord. Mice treated with AAV2/1-hIGF-1 and analyzed 8 months later showed changes in endogenous Bax and Bcl-xl levels in spinal cord motor neurons that were consistent with IGF-1-mediated anti-apoptotic effects on motor neurons. However, although AAV2/1-hIGF-1 treatment reduced the extent of motor neuron cell death, the majority of rescued motor neurons were non-functional, as they lacked axons that innervated the muscles. Furthermore, treated SMA mice exhibited abnormal muscle fibers, aberrant neuromuscular junction structure, and impaired performance on motor function tests. These data indicate that although CNS-directed expression of IGF-1 could reduce motor neuron cell death, this did not translate to improvements in motor function in an adult mouse model of type III SMA. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Native and Complexed IGF-1: Biodistribution and Pharmacokinetics in Infantile Neuronal Ceroid Lipofuscinosis

    Directory of Open Access Journals (Sweden)

    Tuulia Huhtala

    2012-01-01

    Full Text Available Infantile neuronal ceroid lipofuscinosis (INCL is a severe neurodegenerative disorder of childhood characterized by selective death of cortical neurons. Insulin-like growth factor 1 (IGF-1 is important in embryonic development and is considered as a potential therapeutic agent for several disorders of peripheral and central nervous systems. In circulation IGF-1 is mainly bound to its carrier protein IGFBP-3. As a therapeutic agent IGF-1 has shown to be more active as free than complexed form. However, this may cause side effects during the prolonged treatment. In addition to IGFBP-3 the bioavailability of IGF-1 can be modulated by using mesoporous silicon nanoparticles (NPs which are optimal carriers for sustained release of unstable peptide hormones like IGF-1. In this study we compared biodistribution, pharmacokinetics, and bioavailability of radiolabeled free IGF-1, IGF-1/IGFBP-3, and IGF-1/NP complexes in a Cln1-/- knockout mouse model. IGF-1/NP was mainly accumulated in liver and spleen in all studied time points, whereas minor and more constant amounts were measured in other organs compared to free IGF-1 or IGF-1/IGFBP-3. Also concentration of IGF-1/NP in blood was relatively high and stable during studied time points suggesting continuous release of IGF-1 from the particles.

  8. Hypoxia promotes apoptosis of neuronal cells through hypoxia-inducible factor-1α-microRNA-204-B-cell lymphoma-2 pathway.

    Science.gov (United States)

    Wang, Xiuwen; Li, Ji; Wu, Dongjin; Bu, Xiangpeng; Qiao, Yong

    2016-01-01

    Neuronal cells are highly sensitive to hypoxia and may be subjected to apoptosis when exposed to hypoxia. Several apoptosis-related genes and miRNAs involve in hypoxia-induced apoptosis. This study aimed to examine the role of HIF1α-miR-204-BCL-2 pathway in hypoxia-induced apoptosis in neuronal cells. Annexin V/propidium iodide assay was performed to analyze cell apoptosis in AGE1.HN and PC12 cells under hypoxic or normoxic conditions. The expression of BCL-2 and miR-204 were determined by Western blot and qRT-PCR. The effects of miR-204 overexpression or knockdown on the expression of BCL-2 were evaluated by luciferase assay and Western blot under hypoxic or normoxic conditions. HIF-1α inhibitor YC-1 and siHIF-1α were employed to determine the effect of HIF-1α on the up-regulation of miR-204 and down-regulation of BCL-2 induced by hypoxia. Apoptosis assay showed the presence of apoptosis induced by hypoxia in neuronal cells. Moreover, we found that hypoxia significantly down-regulated the expression of BCL-2, and increased the mRNA level of miR-204 in neuronal cells than that in control. Bioinformatic analysis and luciferase reporter assay demonstrated that miR-204 directly targeted and regulated the expression of BCL-2. Specifically, the expression of BCL-2 was inhibited by miR-204 mimic and enhanced by miR-204 inhibitor. Furthermore, we detected that hypoxia induced cell apoptosis via HIF-1α/miR-204/BCL-2 in neuronal cells. This study demonstrated that HIF-1α-miR-204-BCL-2 pathway contributed to apoptosis of neuronal cells induced by hypoxia, which could potentially be exploited to prevent spinal cord ischemia-reperfusion injury. © 2015 by the Society for Experimental Biology and Medicine.

  9. Extracellular signal-regulated kinase 1 and 2 are not required for GnRH neuron development and normal female reproductive axis function in mice.

    Science.gov (United States)

    Wierman, Margaret E; Xu, Mei; Pierce, A; Bliesner, B; Bliss, S P; Roberson, M S

    2012-01-01

    Selective deletion of extracellular signal-regulated kinase (ERK) 1 and ERK2 in the pituitary gonadotrope and ovarian granulosa cells disrupts female reproductive axis function. Thus, we asked if ERK1 and ERK2 are critical for GnRH neuron ontogeny or the central control of female reproductive function. GnRH-Cre-recombinase (Cre+) expressing mice were crossed with mice with a global deletion of ERK1 and a floxed ERK2 allele (Erk1-/Erk2fl/fl) to selectively delete ERK2 in GnRH neurons. Cre-recombinase mRNA was selectively expressed in the brain of Cre+ mice. GnRH neuron number and location were determined during embryogenesis and in the adult. GnRH neuron counts at E15 did not differ between experimental and control groups (1,198 ± 65 and 1,160 ± 80 respectively, p = NS). In adults, numbers of GnRH neurons in the GnRHCre+Erk1-/Erk2- mice (741 ± 157) were similar to those in controls (756 ± 7), without alteration in their distribution across the forebrain. ERK1 and 2 deficiency did not alter the timing of vaginal opening, age at first estrus, or estrous cyclicity. Although ERK1 and 2 are components of a dominant signaling pathway in GnRH neuronal cells that modulates survival and control of GnRH gene expression, other signaling pathways compensate for their deletion in vivo to allow GnRH neuron survival and targeting and normal onset of female sexual maturation and reproductive function. In contrast to effects at the pituitary and the ovary, ERK1 and ERK2 are dispensable at the level of the GnRH neuron. Copyright © 2011 S. Karger AG, Basel.

  10. 76 FR 78594 - Reporting of Specified Foreign Financial Assets

    Science.gov (United States)

    2011-12-19

    ... Reporting of Specified Foreign Financial Assets AGENCY: Internal Revenue Service (IRS), Treasury. ACTION... foreign financial assets and the value of those assets is more than the applicable reporting threshold... hold specified foreign financial assets generally will be excepted from reporting such assets under...

  11. The 5-HT1A serotonin receptor is located on calbindin- and parvalbumin-containing neurons in the rat brain

    DEFF Research Database (Denmark)

    Aznar, Susana; Qian, Zhaoxia; Shah, Reshma

    2003-01-01

    distributed in the rat brain, with a particularly high density in the limbic system. The receptor's localization in the different neuronal subtypes, which may be of importance for understanding its role in neuronal circuitries, is, however, unknown. In this study we show by immunocytochemical double......-labeling techniques, that the 5-HT(1A) receptor is present on both pyramidal and principal cells, and calbindin- and parvalbumin-containing neurons, which generally define two different subtypes of interneurons. Moreover, semiquantitative analysis showed that the receptor's distribution in the different neuronal...... types varies between brain areas. In cortex, hippocampus, hypothalamus, and amygdala the receptor was located on both principal cells and calbindin- and parvalbumin-containing neurons. In septum and thalamus, the receptor was mostly present on calbindin- and parvalbumin-containing cells. Especially...

  12. Phase Locking of Multiple Single Neurons to the Local Field Potential in Cat V1.

    Science.gov (United States)

    Martin, Kevan A C; Schröder, Sylvia

    2016-02-24

    The local field potential (LFP) is thought to reflect a temporal reference for neuronal spiking, which may facilitate information coding and orchestrate the communication between neural populations. To explore this proposed role, we recorded the LFP and simultaneously the spike activity of one to three nearby neurons in V1 of anesthetized cats during the presentation of drifting sinusoidal gratings, binary dense noise stimuli, and natural movies. In all stimulus conditions and during spontaneous activity, the average LFP power at frequencies >20 Hz was higher when neurons were spiking versus not spiking. The spikes were weakly but significantly phase locked to all frequencies of the LFP. The average spike phase of the LFP was stable across high and low levels of LFP power, but the strength of phase locking at low frequencies (≤10 Hz) increased with increasing LFP power. In a next step, we studied how strong stimulus responses of single neurons are reflected in the LFP and the LFP-spike relationship. We found that LFP power was slightly increased and phase locking was slightly stronger during strong compared with weak stimulus-locked responses. In summary, the coupling strength between high frequencies of the LFP and spikes was not strongly modulated by LFP power, which is thought to reflect spiking synchrony, nor was it strongly influenced by how strongly the neuron was driven by the stimulus. Furthermore, a comparison between neighboring neurons showed no clustering of preferred LFP phase. We argue that hypotheses on the relevance of phase locking in their current form are inconsistent with our findings. Copyright © 2016 the authors 0270-6474/16/362494-09$15.00/0.

  13. Curcumin ameliorates hippocampal neuron damage induced by human immunodeficiency virus-1

    OpenAIRE

    Tang, Hongmei; Pan, Rui; Fang, Wenli; Xing, Yanyan; Chen, Dexi; Chen, Xiaobao; Yu, Yuanyuan; Wang, Junbing; Gong, Zheng; Xiong, Guoyin; Dong, Jun

    2013-01-01

    Our previous studies have shown that infection with the gp120 V3 loop can cause human immunodeficiency virus-1 associated neurocognitive disorders. Curcumin has been shown to improve these effects to some degree, but the precise mechanisms remain unknown. The present study analyzed the neuroprotective effect and mechanism of curcumin in relation to hippocampal neurons. Results showed that 1 nmol/L gp120 V3 loop suppressed the growth of synapses. After administration of 1 μmol/L curcumin, syna...

  14. Regulation of Na(+)/K(+)-ATPase by nuclear respiratory factor 1: implication in the tight coupling of neuronal activity, energy generation, and energy consumption.

    Science.gov (United States)

    Johar, Kaid; Priya, Anusha; Wong-Riley, Margaret T T

    2012-11-23

    NRF-1 regulates mediators of neuronal activity and energy generation. NRF-1 transcriptionally regulates Na(+)/K(+)-ATPase subunits α1 and β1. NRF-1 functionally regulates mediators of energy consumption in neurons. NRF-1 mediates the tight coupling of neuronal activity, energy generation, and energy consumption at the molecular level. Energy generation and energy consumption are tightly coupled to neuronal activity at the cellular level. Na(+)/K(+)-ATPase, a major energy-consuming enzyme, is well expressed in neurons rich in cytochrome c oxidase, an important enzyme of the energy-generating machinery, and glutamatergic receptors that are mediators of neuronal activity. The present study sought to test our hypothesis that the coupling extends to the molecular level, whereby Na(+)/K(+)-ATPase subunits are regulated by the same transcription factor, nuclear respiratory factor 1 (NRF-1), found recently by our laboratory to regulate all cytochrome c oxidase subunit genes and some NMDA and AMPA receptor subunit genes. By means of multiple approaches, including in silico analysis, electrophoretic mobility shift and supershift assays, in vivo chromatin immunoprecipitation, promoter mutational analysis, and real-time quantitative PCR, NRF-1 was found to functionally bind to the promoters of Atp1a1 and Atp1b1 genes but not of the Atp1a3 gene in neurons. The transcripts of Atp1a1 and Atp1b1 subunit genes were up-regulated by KCl and down-regulated by tetrodotoxin. Atp1b1 is positively regulated by NRF-1, and silencing of NRF-1 with small interference RNA blocked the up-regulation of Atp1b1 induced by KCl, whereas overexpression of NRF-1 rescued these transcripts from being suppressed by tetrodotoxin. On the other hand, Atp1a1 is negatively regulated by NRF-1. The binding sites of NRF-1 on Atp1a1 and Atp1b1 are conserved among mice, rats, and humans. Thus, NRF-1 regulates key Na(+)/K(+)-ATPase subunits and plays an important role in mediating the tight coupling between

  15. Long descending cervical propriospinal neurons differ from thoracic propriospinal neurons in response to low thoracic spinal injury

    Directory of Open Access Journals (Sweden)

    Stelzner Dennis J

    2010-11-01

    Full Text Available Abstract Background Propriospinal neurons, with axonal projections intrinsic to the spinal cord, have shown a greater regenerative response than supraspinal neurons after axotomy due to spinal cord injury (SCI. Our previous work focused on the response of axotomized short thoracic propriospinal (TPS neurons following a low thoracic SCI (T9 spinal transection or moderate spinal contusion injury in the rat. The present investigation analyzes the intrinsic response of cervical propriospinal neurons having long descending axons which project into the lumbosacral enlargement, long descending propriospinal tract (LDPT axons. These neurons also were axotomized by T9 spinal injury in the same animals used in our previous study. Results Utilizing laser microdissection (LMD, qRT-PCR, and immunohistochemistry, we studied LDPT neurons (located in the C5-C6 spinal segments between 3-days, and 1-month following a low thoracic (T9 spinal cord injury. We examined the response of 89 genes related to growth factors, cell surface receptors, apoptosis, axonal regeneration, and neuroprotection/cell survival. We found a strong and significant down-regulation of ~25% of the genes analyzed early after injury (3-days post-injury with a sustained down-regulation in most instances. In the few genes that were up-regulated (Actb, Atf3, Frs2, Hspb1, Nrap, Stat1 post-axotomy, the expression for all but one was down-regulated by 2-weeks post-injury. We also compared the uninjured TPS control neurons to the uninjured LDPT neurons used in this experiment for phenotypic differences between these two subpopulations of propriospinal neurons. We found significant differences in expression in 37 of the 84 genes examined between these two subpopulations of propriospinal neurons with LDPT neurons exhibiting a significantly higher base line expression for all but 3 of these genes compared to TPS neurons. Conclusions Taken collectively these data indicate a broad overall down

  16. Protein Kinase C-Related Kinase (PKN/PRK). Potential Key-Role for PKN1 in Protection of Hypoxic Neurons.

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    Thauerer, Bettina; Zur Nedden, Stephanie; Baier-Bitterlich, Gabriele

    2014-05-01

    Serine/threonine protein kinase C-related kinase (PKN/PRK) is a family of three isoenzymes (PKN1, PKN2, PKN3), which are widely distributed in eukaryotic organisms and share the same overall domain structure. The Nterminal region encompasses a conserved repeated domain, termed HR1a-c as well as a HR2/C2 domain. The serine/threonine kinase domain is found in the C-terminal region of the protein and shows high sequence homology to other members of the PKC superfamily. In neurons, PKN1 is the most abundant isoform and has been implicated in a variety of functions including cytoskeletal organization and neuronal differentiation and its deregulation may contribute to neuropathological processes such as amyotrophic lateral sclerosis and Alzheimer's disease. We have recently identified a candidate role of PKN1 in the regulation of neuroprotective processes during hypoxic stress. Our key findings were that: 1) the activity of PKN1 was significantly increased by hypoxia (1% O2) and neurotrophins (nerve growth factor and purine nucleosides); 2) Neuronal cells, deficient of PKN1 showed a decrease of cell viability and neurite formation along with a disturbance of the F-actinassociated cytoskeleton; 3) Purine nucleoside-mediated neuroprotection during hypoxia was severely hampered in PKN1 deficient neuronal cells, altogether suggesting a potentially critical role of PKN1 in neuroprotective processes. This review gives an up-to-date overview of the PKN family with a special focus on the neuroprotective role of PKN1 in hypoxia.

  17. Perifornical orexinergic neurons modulate REM sleep by influencing locus coeruleus neurons in rats.

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    Choudhary, R C; Khanday, M A; Mitra, A; Mallick, B N

    2014-10-24

    Activation of the orexin (OX)-ergic neurons in the perifornical (PeF) area has been reported to induce waking and reduce rapid eye movement sleep (REMS). The activities of OX-ergic neurons are maximum during active waking and they progressively reduce during non-REMS (NREMS) and REMS. Apparently, the locus coeruleus (LC) neurons also behave in a comparable manner as that of the OX-ergic neurons particularly in relation to waking and REMS. Further, as PeF OX-ergic neurons send dense projections to LC, we argued that the former could drive the LC neurons to modulate waking and REMS. Studies in freely moving normally behaving animals where simultaneously neuro-chemo-anatomo-physio-behavioral information could be deciphered would significantly strengthen our understanding on the regulation of REMS. Therefore, in this study in freely behaving chronically prepared rats we stimulated the PeF neurons without or with simultaneous blocking of specific subtypes of OX-ergic receptors in the LC while electrophysiological recording characterizing sleep-waking was continued. Single dose of glutamate stimulation as well as sustained mild electrical stimulation of PeF (both bilateral) significantly increased waking and reduced REMS as compared to baseline. Simultaneous application of OX-receptor1 (OX1R) antagonist bilaterally into the LC prevented PeF stimulation-induced REMS suppression. Also, the effect of electrical stimulation of the PeF was long lasting as compared to that of the glutamate stimulation. Further, sustained electrical stimulation significantly decreased both REMS duration as well as REMS frequency, while glutamate stimulation decreased REMS duration only. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Inhibition of TRPA1 channel activity in sensory neurons by the glial cell line-derived neurotrophic factor family member, artemin

    Directory of Open Access Journals (Sweden)

    Wang Shenglan

    2011-05-01

    Full Text Available Abstract Background The transient receptor potential (TRP channel subtype A1 (TRPA1 is known to be expressed on sensory neurons and respond to changes in temperature, pH and local application of certain noxious chemicals such as allyl isothiocyanate (AITC. Artemin is a neuronal survival and differentiation factor and belongs to the glial cell line-derived neurotrophic factor (GDNF family. Both TRPA1 and artemin have been reported to be involved in pathological pain initiation and maintenance. In the present study, using whole-cell patch clamp recording technique, in situ hybridization and behavioral analyses, we examined the functional interaction between TRPA1 and artemin. Results We found that 85.8 ± 1.9% of TRPA1-expressing neurons also expressed GDNF family receptor alpha 3 (GFR α3, and 87.5 ± 4.1% of GFRα3-expressing neurons were TRPA1-positive. In whole-cell patch clamp analysis, a short-term treatment of 100 ng/ml artemin significantly suppressed the AITC-induced TRPA1 currents. A concentration-response curve of AITC resulting from the effect of artemin showed that this inhibition did not change EC50 but did lower the AITC-induced maximum response. In addition, pre-treatment of artemin significantly suppressed the number of paw lifts induced by intraplantar injection of AITC, as well as the formalin-induced pain behaviors. Conclusions These findings that a short-term application of artemin inhibits the TRPA1 channel's activity and the sequential pain behaviors suggest a role of artemin in regulation of sensory neurons.

  19. Single-cell axotomy of cultured hippocampal neurons integrated in neuronal circuits.

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    Gomis-Rüth, Susana; Stiess, Michael; Wierenga, Corette J; Meyn, Liane; Bradke, Frank

    2014-05-01

    An understanding of the molecular mechanisms of axon regeneration after injury is key for the development of potential therapies. Single-cell axotomy of dissociated neurons enables the study of the intrinsic regenerative capacities of injured axons. This protocol describes how to perform single-cell axotomy on dissociated hippocampal neurons containing synapses. Furthermore, to axotomize hippocampal neurons integrated in neuronal circuits, we describe how to set up coculture with a few fluorescently labeled neurons. This approach allows axotomy of single cells in a complex neuronal network and the observation of morphological and molecular changes during axon regeneration. Thus, single-cell axotomy of mature neurons is a valuable tool for gaining insights into cell intrinsic axon regeneration and the plasticity of neuronal polarity of mature neurons. Dissociation of the hippocampus and plating of hippocampal neurons takes ∼2 h. Neurons are then left to grow for 2 weeks, during which time they integrate into neuronal circuits. Subsequent axotomy takes 10 min per neuron and further imaging takes 10 min per neuron.

  20. Quantitative immuno-electron microscopic analysis of depolarization-induced expression of PGC-1alpha in cultured rat visual cortical neurons.

    Science.gov (United States)

    Meng, Hui; Liang, Huan Ling; Wong-Riley, Margaret

    2007-10-17

    Peroxisome proliferator-activated receptor-gamma coactivator 1alpha (PGC- 1alpha) is a coactivator of nuclear receptors and other transcription factors that regulate several metabolic processes, including mitochondrial biogenesis, energy homeostasis, respiration, and gluconeogenesis. PGC-1alpha plays a vital role in stimulating genes that are important to oxidative metabolism and other mitochondrial functions in brown adipose tissue and skeleton muscles, but the significance of PGC-1alpha in the brain remains elusive. The goal of our present study was to determine by means of quantitative immuno-electron microscopy the expression of PGC-1alpha in cultured rat visual cortical neurons under normal conditions as well as after depolarizing stimulation for varying periods of time. Our results showed that: (a) PGC-1alpha was normally located in both the nucleus and the cytoplasm. In the nucleus, PGC-1alpha was associated mainly with euchromatin rather than heterochromatin, consistent with active involvement in transcription. In the cytoplasm, it was associated mainly with free ribosomes. (b) Neuronal depolarization by KCl for 0.5 h induced a significant increase in PGC-1alpha labeling density in both the nucleus and the cytoplasm (Pneuronal activity by synthesizing more proteins in the cytoplasm and translocating them to the nucleus for gene activation. PGC-1alpha level in neurons is, therefore, tightly regulated by neuronal activity.