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Sample records for cd200 receptor-mediated regulation

  1. Brain innate immunity in the regulation of neuroinflammation: therapeutic strategies by modulating CD200-CD200R interaction involve the cannabinoid system.

    Science.gov (United States)

    Hernangómez, Miriam; Carrillo-Salinas, Francisco J; Mecha, Miriam; Correa, Fernando; Mestre, Leyre; Loría, Frida; Feliú, Ana; Docagne, Fabian; Guaza, Carmen

    2014-01-01

    The central nervous system (CNS) innate immune response includes an arsenal of molecules and receptors expressed by professional phagocytes, glial cells and neurons that is involved in host defence and clearance of toxic and dangerous cell debris. However, any uncontrolled innate immune responses within the CNS are widely recognized as playing a major role in the development of autoimmune disorders and neurodegeneration, with multiple sclerosis (MS) Alzheimer's disease (AD) being primary examples. Hence, it is important to identify the key regulatory mechanisms involved in the control of CNS innate immunity and which could be harnessed to explore novel therapeutic avenues. Neuroimmune regulatory proteins (NIReg) such as CD95L, CD200, CD47, sialic acid, complement regulatory proteins (CD55, CD46, fH, C3a), HMGB1, may control the adverse immune responses in health and diseases. In the absence of these regulators, when neurons die by apoptosis, become infected or damaged, microglia and infiltrating immune cells are free to cause injury as well as an adverse inflammatory response in acute and chronic settings. We will herein provide new emphasis on the role of the pair CD200-CD200R in MS and its experimental models: experimental autoimmune encephalomyelitis (EAE) and Theiler's virus induced demyelinating disease (TMEV-IDD). The interest of the cannabinoid system as inhibitor of inflammation prompt us to introduce our findings about the role of endocannabinoids (eCBs) in promoting CD200-CD200 receptor (CD200R) interaction and the benefits caused in TMEV-IDD. Finally, we also review the current data on CD200-CD200R interaction in AD, as well as, in the aging brain. PMID:24588829

  2. Altered expression of mRNAs implicated in osteogenesis under conditions of simulated microgravity is regulated by CD200:CD200R

    Science.gov (United States)

    Lee, Lydia; Kos, Olha; Gorczynski, Reginald M.

    2008-12-01

    Mouse calvarial cells grown under simulated microgravity conditions (neutral buoyancy) show preferential differentiation towards the osteoclast lineage, as defined by surrogate mRNAs, bone nodule growth and TRAP+ cells, when compared with cells cultured under normal gravity conditions. This effect was suppressed in cultures which contained the immunoregulatory molecule CD200, and conversely enhanced by anti-CD200 mAb. Concomitant increases occur in expression of inflammatory cytokines, and their mRNAs, under simulated microgravity conditions. Again cultures containing exogenous CD200 showed suppressed cytokine and cytokine mRNA expression. Further alterations in osteoclastogenesis were seen using cells isolated from cytokine-receptor knockout mice. We conclude that, as assessed by altered expression of mRNAs associated with osteoblast differentiation, CD200:CD200R interactions play an important regulatory role in the enhanced osteoclastogenesis seen under simulated microgravity conditions, with changes in cytokine expression further modulating this effect.

  3. Dopamine receptor-mediated regulation of neuronal "clock" gene expression.

    Science.gov (United States)

    Imbesi, M; Yildiz, S; Dirim Arslan, A; Sharma, R; Manev, H; Uz, T

    2009-01-23

    Using a transgenic mice model (i.e. "clock" knockouts), clock transcription factors have been suggested as critical regulators of dopaminergic behaviors induced by drugs of abuse. Moreover, it has been shown that systemic administration of psychostimulants, such as cocaine and methamphetamine regulates the striatal expression of clock genes. However, it is not known whether dopamine receptors mediate these regulatory effects of psychostimulants at the cellular level. Primary striatal neurons in culture express dopamine receptors as well as clock genes and have been successfully used in studying dopamine receptor functioning. Therefore, we investigated the role of dopamine receptors on neuronal clock gene expression in this model using specific receptor agonists. We found an inhibitory effect on the expression of mClock and mPer1 genes with the D2-class (i.e. D2/D3) receptor agonist quinpirole. We also found a generalized stimulatory effect on the expression of clock genes mPer1, mClock, mNPAS2 (neuronal PAS domain protein 2), and mBmal1 with the D1-class (i.e. D1) receptor agonist SKF38393. Further, we tested whether systemic administration of dopamine receptor agonists causes similar changes in striatal clock gene expression in vivo. We found quinpirole-induced alterations in mPER1 protein levels in the mouse striatum (i.e. rhythm shift). Collectively, our results indicate that the dopamine receptor system may mediate psychostimulant-induced changes in clock gene expression. Using striatal neurons in culture as a model, further research is needed to better understand how dopamine signaling modulates the expression dynamics of clock genes (i.e. intracellular signaling pathways) and thereby influences neuronal gene expression, neuronal transmission, and brain functioning. PMID:19017537

  4. Dopamine receptor-mediated regulation of neuronal “clock” gene expression

    OpenAIRE

    Imbesi, Marta; Yildiz, Sevim; Arslan, Ahmet Dirim; Sharma, Rajiv; Manev, Hari; Uz, Tolga

    2008-01-01

    Using transgenic mice model (i.e., “clock” knockouts), clock transcription factors have been suggested as critical regulators of dopaminergic behaviors induced by drugs of abuse. Moreover, it has been shown that systemic administration of psychostimulants, such as cocaine and methamphetamine regulate the striatal expression of clock genes. However, it is not known whether dopamine receptors mediate these regulatory effects of psychostimulants at the cellular level. Primary striatal neurons in...

  5. DMPD: Translational mini-review series on Toll-like receptors: networks regulated byToll-like receptors mediate innate and adaptive immunity. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available e receptors: networks regulated byToll-like receptors mediate innate and adaptive...ed byToll-like receptors mediate innate and adaptive immunity. Authors Parker LC, Prince LR, Sabroe I. Publi...d byToll-like receptors mediate innate and adaptive immunity. Parker LC, Prince LR, Sabroe I. Clin Exp Immun...17223959 Translational mini-review series on Toll-like receptors: networks regulate

  6. Myxoma virus M141R expresses a viral CD200 (vOX-2) that is responsible for down-regulation of macrophage and T-cell activation in vivo.

    Science.gov (United States)

    Cameron, Cheryl M; Barrett, John W; Liu, Liying; Lucas, Alexandra R; McFadden, Grant

    2005-05-01

    M141R is a myxoma virus gene that encodes a cell surface protein with significant amino acid similarity to the family of cellular CD200 (OX-2) proteins implicated in the regulation of myeloid lineage cell activation. The creation of an M141R deletion mutant myxoma virus strain (vMyx141KO) and its subsequent infection of European rabbits demonstrated that M141R is required for the full development of a lethal infection in vivo but is not required for efficient virus replication in susceptible cell lines in vitro. Minor secondary sites of infection were detected in the majority of rabbits infected with the M141R deletion mutant, demonstrating that the M141R protein is not required for the dissemination of virus within the host. When compared to wild-type myxoma virus-infected rabbits, vMyx141KO-infected rabbits showed higher activation levels of both monocytes/macrophages and lymphocytes in situ through assessments of inducible nitric oxide synthase-positive and CD25(+) infiltrating cells in infected and lymphoid tissues. Purified peripheral blood mononuclear cells from vMyx141KO-infected rabbits demonstrated an increased ability to express gamma interferon upon activation by phorbol myristate acetate plus ionomycin compared to cells purified from wild-type myxoma virus-infected rabbits. We concluded that the M141R protein is a bona fide CD200-like immunomodulator protein which is required for the full pathogenesis of myxoma virus in the European rabbit and that its loss from the virus results in increased activation levels of macrophages in infected lesions and draining lymph nodes as well as an increased activation level of circulating T lymphocytes during infection. We propose a model whereby M141R transmits inhibitory signals to tissue macrophages, and possibly resident CD200R(+) dendritic cells, that reduce their ability to antigenically prime lymphocytes and possibly provides anergic signals to T cells directly. PMID:15857991

  7. Xenobiotic Receptor-Mediated Regulation of Intestinal Barrier Function and Innate Immunity

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    Harmit S. Ranhotra

    2016-07-01

    Full Text Available The molecular basis for the regulation of the intestinal barrier is a very fertile research area. A growing body of knowledge supports the targeting of various components of intestinal barrier function as means to treat a variety of diseases, including the inflammatory bowel diseases. Herein, we will summarize the current state of knowledge of key xenobiotic receptor regulators of barrier function, highlighting recent advances, such that the field and its future are succinctly reviewed. We posit that these receptors confer an additional dimension of host-microbe interaction in the gut, by sensing and responding to metabolites released from the symbiotic microbiota, in innate immunity and also in host drug metabolism. The scientific evidence for involvement of the receptors and its molecular basis for the control of barrier function and innate immunity regulation would serve as a rationale towards development of non-toxic probes and ligands as drugs.

  8. Bidirectional regulation of angiogenesis by phytoestrogens through estrogen receptor-mediated signaling networks.

    Science.gov (United States)

    Liu, Hai-Xin; Wang, Yu; Lu, Qing; Yang, Ming-Zhu; Fan, Guan-Wei; Karas, Richard H; Gao, Xiu-Mei; Zhu, Yan

    2016-04-01

    Sex hormone estrogen is one of the most active intrinsic angiogenesis regulators; its therapeutic use has been limited due to its carcinogenic potential. Plant-derived phytoestrogens are attractive alternatives, but reports on their angiogenic activities often lack in-depth analysis and sometimes are controversial. Herein, we report a data-mining study with the existing literature, using IPA system to classify and characterize phytoestrogens based on their angiogenic properties and pharmacological consequences. We found that pro-angiogenic phytoestrogens functioned predominantly as cardiovascular protectors whereas anti-angiogenic phytoestrogens played a role in cancer prevention and therapy. This bidirectional regulation were shown to be target-selective and, for the most part, estrogen-receptor-dependent. The transactivation properties of ERα and ERβ by phytoestrogens were examined in the context of angiogenesis-related gene transcription. ERα and ERβ were shown to signal in opposite ways when complexed with the phytoestrogen for bidirectional regulation of angiogenesis. With ERα, phytoestrogen activated or inhibited transcription of some angiogenesis-related genes, resulting in the promotion of angiogenesis, whereas, with ERβ, phytoestrogen regulated transcription of angiogenesis-related genes, resulting in inhibition of angiogenesis. Therefore, the selectivity of phytoestrogen to ERα and ERβ may be critical in the balance of pro- or anti-angiogenesis process. PMID:27114311

  9. Regulation of VH replacement by B cell receptor-mediated signaling in human immature B cells.

    Science.gov (United States)

    Liu, Jing; Lange, Miles D; Hong, Sang Yong; Xie, Wanqin; Xu, Kerui; Huang, Lin; Yu, Yangsheng; Ehrhardt, Götz R A; Zemlin, Michael; Burrows, Peter D; Su, Kaihong; Carter, Robert H; Zhang, Zhixin

    2013-06-01

    VH replacement provides a unique RAG-mediated recombination mechanism to edit nonfunctional IgH genes or IgH genes encoding self-reactive BCRs and contributes to the diversification of Ab repertoire in the mouse and human. Currently, it is not clear how VH replacement is regulated during early B lineage cell development. In this article, we show that cross-linking BCRs induces VH replacement in human EU12 μHC(+) cells and in the newly emigrated immature B cells purified from peripheral blood of healthy donors or tonsillar samples. BCR signaling-induced VH replacement is dependent on the activation of Syk and Src kinases but is inhibited by CD19 costimulation, presumably through activation of the PI3K pathway. These results show that VH replacement is regulated by BCR-mediated signaling in human immature B cells, which can be modulated by physiological and pharmacological treatments.

  10. Protein kinase C regulates tonic GABAA receptor-mediated inhibition in the hippocampus and thalamus

    Science.gov (United States)

    Bright, Damian P; Smart, Trevor G

    2013-01-01

    Tonic inhibition mediated by extrasynaptic GABAA receptors (GABAARs) is an important regulator of neuronal excitability. Phosphorylation by protein kinase C (PKC) provides a key mode of regulation for synaptic GABAARs underlying phasic inhibition; however, less attention has been focused on the plasticity of tonic inhibition and whether this can also be modulated by receptor phosphorylation. To address this issue, we used whole-cell patch clamp recording in acute murine brain slices at both room and physiological temperatures to examine the effects of PKC-mediated phosphorylation on tonic inhibition. Recordings from dentate gyrus granule cells in the hippocampus and dorsal lateral geniculate relay neurons in the thalamus demonstrated that PKC activation caused downregulation of tonic GABAAR-mediated inhibition. Conversely, inhibition of PKC resulted in an increase in tonic GABAAR activity. These findings were corroborated by experiments on human embryonic kidney 293 cells expressing recombinant α4β2δ GABAARs, which represent a key extrasynaptic GABAAR isoform in the hippocampus and thalamus. Using bath application of low GABA concentrations to mimic activation by ambient neurotransmitter, we demonstrated a similar inhibition of receptor function following PKC activation at physiological temperature. Live cell imaging revealed that this was correlated with a loss of cell surface GABAARs. The inhibitory effects of PKC activation on α4β2δ GABAAR activity appeared to be mediated by direct phosphorylation at a previously identified site on the β2 subunit, serine 410. These results indicate that PKC-mediated phosphorylation can be an important physiological regulator of tonic GABAAR-mediated inhibition. PMID:24102973

  11. Voltage dependent anion channel-1 regulates death receptor mediated apoptosis by enabling cleavage of caspase-8

    International Nuclear Information System (INIS)

    Activation of the extrinsic apoptosis pathway by tumour necrosis factor related apoptosis inducing ligand (TRAIL) is a novel therapeutic strategy for treating cancer that is currently under clinical evaluation. Identification of molecular biomarkers of resistance is likely to play an important role in predicting clinical anti tumour activity. The involvement of the mitochondrial type 1 voltage dependent anion channel (VDAC1) in regulating apoptosis has been highly debated. To date, a functional role in regulating the extrinsic apoptosis pathway has not been formally excluded. We carried out stable and transient RNAi knockdowns of VDAC1 in non-small cell lung cancer cells, and stimulated the extrinsic apoptotic pathway principally by incubating cells with the death ligand TRAIL. We used in-vitro apoptotic and cell viability assays, as well as western blot for markers of apoptosis, to demonstrate that TRAIL-induced toxicity is VDAC1 dependant. Confocal microscopy and mitochondrial fractionation were used to determine the importance of mitochondria for caspase-8 activation. Here we show that either stable or transient knockdown of VDAC1 is sufficient to antagonize TRAIL mediated apoptosis in non-small cell lung cancer (NSCLC) cells. Specifically, VDAC1 is required for processing of procaspase-8 to its fully active p18 form at the mitochondria. Loss of VDAC1 does not alter mitochondrial sensitivity to exogenous caspase-8-cleaved BID induced mitochondrial depolarization, even though VDAC1 expression is essential for TRAIL dependent activation of the intrinsic apoptosis pathway. Furthermore, expression of exogenous VDAC1 restores the apoptotic response to TRAIL in cells in which endogenous VDAC1 has been selectively silenced. Expression of VDAC1 is required for full processing and activation of caspase-8 and supports a role for mitochondria in regulating apoptosis signaling via the death receptor pathway

  12. Dopamine D2 Receptor-Mediated Regulation of Pancreatic β Cell Mass

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    Daisuke Sakano

    2016-07-01

    Full Text Available Understanding the molecular mechanisms that regulate β cell mass and proliferation is important for the treatment of diabetes. Here, we identified domperidone (DPD, a dopamine D2 receptor (DRD2 antagonist that enhances β cell mass. Over time, islet β cell loss occurs in dissociation cultures, and this was inhibited by DPD. DPD increased proliferation and decreased apoptosis of β cells through increasing intracellular cAMP. DPD prevented β cell dedifferentiation, which together highly contributed to the increased β cell mass. DRD2 knockdown phenocopied the effects of domperidone and increased the number of β cells. Drd2 overexpression sensitized the dopamine responsiveness of β cells and increased apoptosis. Further analysis revealed that the adenosine agonist 5′-N-ethylcarboxamidoadenosine, a previously identified promoter of β cell proliferation, acted with DPD to increase the number of β cells. In humans, dopamine also modulates β cell mass through DRD2 and exerts an inhibitory effect on adenosine signaling.

  13. Rab20 regulates phagosome maturation in RAW264 macrophages during Fc gamma receptor-mediated phagocytosis.

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    Youhei Egami

    Full Text Available Rab20, a member of the Rab GTPase family, is known to be involved in membrane trafficking, however its implication in FcγR-mediated phagocytosis is unclear. We examined the spatiotemporal localization of Rab20 during phagocytosis of IgG-opsonized erythrocytes (IgG-Es in RAW264 macrophages. By the live-cell imaging of fluorescent protein-fused Rab20, it was shown that Rab20 was transiently associated with the phagosomal membranes. During the early stage of phagosome formation, Rab20 was not localized on the membranes of phagocytic cups, but was gradually recruited to the newly formed phagosomes. Although Rab20 was colocalized with Rab5 to some extent, the association of Rab20 with the phagosomes persisted even after the loss of Rab5 from the phagosomal membranes. Then, Rab20 was colocalized with Rab7 and Lamp1, late endosomal/lysosomal markers, on the internalized phagosomes. Moreover, our analysis of Rab20 mutant expression revealed that the maturation of phagosomes was significantly delayed in cells expressing the GDP-bound mutant Rab20-T19N. These data suggest that Rab20 is an important component of phagosome and regulates the phagosome maturation during FcγR-mediated phagocytosis.

  14. Ku proteins function as corepressors to regulate farnesoid X receptor-mediated gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, Masae; Kunimoto, Masaaki; Nishizuka, Makoto; Osada, Shigehiro [Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603 (Japan); Imagawa, Masayoshi, E-mail: imagawa@phar.nagoya-cu.ac.jp [Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi 467-8603 (Japan)

    2009-12-18

    The farnesoid X receptor (FXR; NR1H4) is a member of the nuclear receptor superfamily and regulates the expression of genes involved in enterohepatic circulation and the metabolism of bile acids. Based on functional analyses, nuclear receptors are divided into regions A-F. To explore the cofactors interacting with FXR, we performed a pull-down assay using GST-fused to the N-terminal A/B region and the C region, which are required for the ligand-independent transactivation and DNA-binding, respectively, of FXR, and nuclear extracts from HeLa cells. We identified DNA-dependent protein kinase catalytic subunit (DNA-PKcs), Ku80, and Ku70 as FXR associated factors. These proteins are known to have an important role in DNA repair, recombination, and transcription. DNA-PKcs mainly interacted with the A/B region of FXR, whereas the Ku proteins interacted with the C region and with the D region (hinge region). Chromatin immunoprecipitation assays revealed that the Ku proteins associated with FXR on the bile salt export pump (BSEP) promoter. Furthermore, we demonstrated that ectopic expression of the Ku proteins decreased the promoter activity and expression of BSEP gene mediated by FXR. These results suggest that the Ku proteins function as corepressors for FXR.

  15. Monoacylglycerol lipase promotes Fcγ receptor-mediated phagocytosis in microglia but does not regulate LPS-induced upregulation of inflammatory cytokines.

    Science.gov (United States)

    Kouchi, Zen

    2015-08-21

    Monoacylglycerol lipase (MAGL) is important for neuroinflammation. However, the regulatory mechanisms underlying its expression and function remain unknown. Lipopolysaccharide (LPS) treatment post-translationally upregulated MAGL expression, whereas it downregulated MAGL transcription through a Stat6-mediated mechanism in microglia. Neither MAGL knockdown nor JZL-184, a selective MAGL inhibitor, suppressed LPS-induced upregulation of inflammatory cytokines in microglia. Moreover, exogenous expression of MAGL in BV-2 microglial cell line, which lacks endogenous MAGL, did not promote the induction of inflammatory cytokines by LPS treatment. Interestingly, MAGL knockdown reduced Fcγ receptor-mediated phagocytosis in primary microglia, and introduction of MAGL into the BV-2 cells increased Fcγ receptor-mediated phagocytosis. Collectively, these results suggest that MAGL regulates phagocytosis, but not LPS-mediated cytokine induction in microglia.

  16. α4 nicotinic acetylcholine receptor modulated by galantamine on nigrostriatal terminals regulates dopamine receptor-mediated rotational behavior.

    Science.gov (United States)

    Inden, Masatoshi; Takata, Kazuyuki; Yanagisawa, Daijiro; Ashihara, Eishi; Tooyama, Ikuo; Shimohama, Shun; Kitamura, Yoshihisa

    2016-03-01

    Galantamine, an acetylcholine esterase (AChE) inhibitor used to treat dementia symptoms, also acts as an allosteric potentiating ligand (APL) at nicotinic acetylcholine receptors (nAChRs). This study was designed to evaluate the allosteric effect of galantamine on nAChR regulation of nigrostrial dopaminergic neuronal function in the hemiparkinsonian rat model established by unilateral nigral 6-hydroxydopamine (6-OHDA) injection. Methamphetamine, a dopamine releaser, induced ipsilateral rotation, whereas dopamine agonists apomorphine (a non-selective dopamine receptor agonist), SKF38393 (a selective dopamine D1 receptor agonist), and quinpirole (a selective dopamine D2 receptor agonist) induced contralateral rotation. When 6-OHDA-injected rats were co-treated with nomifensine, a dopamine transporter inhibitor, a more pronounced and a remarkable effect of nicotine and galantamine was observed. Under these conditions, the combination of nomifensine with nicotine or galantamine induced the ipsilateral rotation similar to the methamphetamine-induced rotational behavior, indicating that nicotine and galantamine also induce dopamine release from striatal terminals. Both nicotine- and galantamine-induced rotations were significantly blocked by flupenthixol (an antagonist of both D1 and D2 dopamine receptors) and mecamylamine (an antagonist of nAChRs), suggesting that galantamine modulation of nAChRs on striatal dopaminergic terminals regulates dopamine receptor-mediated movement. Immunohistochemical staining showed that α4 nAChRs were highly expressed on striatal dopaminergic terminals, while no α7 nAChRs were detected. Pretreatment with the α4 nAChR antagonist dihydroxy-β-erythroidine significantly inhibited nicotine- and galantamine-induced rotational behaviors, whereas pretreatment with the α7 nAChR antagonist methyllycaconitine was ineffective. Moreover, the α4 nAChR agonist ABT-418 induced ipsilateral rotation, while the α7 nAChR agonist PNU282987 had no

  17. The Orphan Nuclear Receptor ERRγ Regulates Hepatic CB1 Receptor-Mediated Fibroblast Growth Factor 21 Gene Expression

    Science.gov (United States)

    Jung, Yoon Seok; Lee, Ji-Min; Kim, Don-Kyu; Lee, Yong-Soo; Kim, Ki-Sun; Kim, Yong-Hoon; Kim, Jina; Lee, Myung-Shik; Lee, In-Kyu; Kim, Seong Heon; Cho, Sung Jin; Jeong, Won-Il; Lee, Chul-Ho; Harris, Robert A.; Choi, Hueng-Sik

    2016-01-01

    Background Fibroblast growth factor 21 (FGF21), a stress inducible hepatokine, is synthesized in the liver and plays important roles in glucose and lipid metabolism. However, the mechanism of hepatic cannabinoid type 1 (CB1) receptor-mediated induction of FGF21 gene expression is largely unknown. Results Activation of the hepatic CB1 receptor by arachidonyl-2’-chloroethylamide (ACEA), a CB1 receptor selective agonist, significantly increased FGF21 gene expression. Overexpression of estrogen-related receptor (ERR) γ increased FGF21 gene expression and secretion both in hepatocytes and mice, whereas knockdown of ERRγ decreased ACEA-mediated FGF21 gene expression and secretion. Moreover, ERRγ, but not ERRα and ERRβ, induced FGF21 gene promoter activity. In addition, deletion and mutation analysis of the FGF21 promoter identified a putative ERRγ-binding motif (AGGTGC, a near-consensus response element). A chromatin immunoprecipitation assay revealed direct binding of ERRγ to the FGF21 gene promoter. Finally, GSK5182, an ERRγ inverse agonist, significantly inhibited hepatic CB1 receptor-mediated FGF21 gene expression and secretion. Conclusion Based on our data, we conclude that ERRγ plays a key role in hepatic CB1 receptor-mediated induction of FGF21 gene expression and secretion. PMID:27455076

  18. Pentosan polysulfate regulates scavenger receptor-mediated, but not fluid-phase, endocytosis in immortalized cerebral endothelial cells.

    Science.gov (United States)

    Deli, M A; Abrahám, C S; Takahata, H; Katamine, S; Niwa, M

    2000-12-01

    1. Effects of pentosan polysulfate (PPS) and the structurally related sulfated polyanions dextran sulfate, fucoidan, and heparin on the scavenger receptor-mediated and fluidphase endocytosis in GP8 immortalized rat brain endothelial cells were investigated. 2. Using 1,1'-dioctadecyl-3,3,3,3'-tetramethylindocarboxyamine perchlorate-labeled acetylated low-density lipoprotein (DiI-AcLDL), we found a binding site with high affinity and low binding capacity, and another one with low affinity and high binding capacity. Increasing ligand concentrations could not saturate DiI-AcLDL uptake. DiI-AcLDL uptake, but not binding, was sensitive to pretreatment with filipin, an inhibitor of caveola formation. 3. PPS (20-200 microg/ml) significantly reduced the binding of DiI-AcLDL after coincubation for 3 hr, though this effect was less expressed after 18 hr. Among other polyanions, only fucoidan decreased the DiI-AcLDL binding after 3 hr, whereas dextran sulfate significantly increased it after 18 hr. PPS treatment induced an increase in DiI-AcLDL uptake, whereas other polysulfated compounds caused a significant reduction. 4. Fluid-phase endocytosis determined by the accumulation of Lucifer yellow was concentration and time dependent in GP8 cells. Coincubation with PPS or other sulfated polyanions could not significantly alter the rate of Lucifer yellow uptake. 5. In conclusion. PPS decreased the binding and increased the uptake of DiI-AcLDL in cerebral endothelial cells, an effect not mimicked by the other polyanions investigated.

  19. Endothelin receptor-mediated vasodilatation

    DEFF Research Database (Denmark)

    Nilsson, David; Wackenfors, Angelica; Gustafsson, Lotta;

    2008-01-01

    Culture of intact arteries is a frequently employed experimental model for investigating the mechanisms governing the regulation of vascular endothelin receptors. Endothelin type A (ET(A)) and type B (ET(B)) receptors on vascular smooth muscle cells are up-regulated in organ culture and the...... enhanced vasoconstriction mimics the changes that occur in cardiovascular disease. The effect of organ culture on endothelial dilatory endothelin ET(B) receptors is not known. We hypothesize that organ culture decreases the endothelin receptor-mediated dilatation and that this is one possible mechanism by...... denudation. The increase in sarafotoxin 6c contraction after removal of the endothelium was more pronounced before than after organ culture, suggesting down-regulated endothelial endothelin ET(B) receptors. Also, the immunofluorescence staining intensities for endothelial endothelin ET(B) receptors were...

  20. Phenotypic and Functional Characterization of Monoclonal Antibodies with Specificity for Rhesus Macaque CD200, CD200R and Mincle.

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    Siddappa N Byrareddy

    Full Text Available Lectin-like molecules and their receptors are cell surface molecules that have been shown to play a role in either facilitating infection or serving as transporters of HIV/SIV in vivo. The role of these lectin-like molecules in the pathogenesis of HIV/SIV infection continues to be defined. In efforts to gain further insight on the potential role of these lectin-like molecules, our laboratory generated monoclonal antibodies (mAb against the human analogs of rhesus macaque CD200, CD200R and Mincle, since the rhesus macaques are accepted as the most reliable animal model to study human HIV infection. The characterization of the cell lineages from the blood and various tissues of rhesus macaques that express these lectin-like molecules are described herein. Among the mononuclear cells, the cells of the myeloid lineage of rhesus macaques are the predominant cell lineages that express readily detectable levels of CD200, CD200R and Mincle that is similar to the expression of Siglec-1 and Siglec-3 reported by our laboratory earlier. Subset analysis revealed that a higher frequency of the CD14+/CD16- subset from normal rhesus macaques express CD200, CD200R and Mincle. Differences in the frequencies and density of expression of these molecules by the gated population of CD14+ cells from various tissues are noted with PBMC and bone marrow expressing the highest and the mononuclear cells isolated from the colon and ileum expressing the lowest levels. While a significant frequency of pDCs and mDCs express Siglec-1/Siglec-3, a much lower frequency expresses CD200, CD200R and Mincle in PBMCs from rhesus macaques. The mAb against CD200 and CD200R but not Mincle appear to inhibit the infection of macrophage tropic SIV/SHIV in vitro. We conclude that these mAbs may have potential to be used as adjunctive therapeutic agents to control/inhibit SIV/HIV infection.

  1. Phenotypic and Functional Characterization of Monoclonal Antibodies with Specificity for Rhesus Macaque CD200, CD200R and Mincle.

    Science.gov (United States)

    Byrareddy, Siddappa N; Little, Dawn; Mayne, Ann E; Villinger, Francois; Ansari, Aftab A

    2015-01-01

    Lectin-like molecules and their receptors are cell surface molecules that have been shown to play a role in either facilitating infection or serving as transporters of HIV/SIV in vivo. The role of these lectin-like molecules in the pathogenesis of HIV/SIV infection continues to be defined. In efforts to gain further insight on the potential role of these lectin-like molecules, our laboratory generated monoclonal antibodies (mAb) against the human analogs of rhesus macaque CD200, CD200R and Mincle, since the rhesus macaques are accepted as the most reliable animal model to study human HIV infection. The characterization of the cell lineages from the blood and various tissues of rhesus macaques that express these lectin-like molecules are described herein. Among the mononuclear cells, the cells of the myeloid lineage of rhesus macaques are the predominant cell lineages that express readily detectable levels of CD200, CD200R and Mincle that is similar to the expression of Siglec-1 and Siglec-3 reported by our laboratory earlier. Subset analysis revealed that a higher frequency of the CD14+/CD16- subset from normal rhesus macaques express CD200, CD200R and Mincle. Differences in the frequencies and density of expression of these molecules by the gated population of CD14+ cells from various tissues are noted with PBMC and bone marrow expressing the highest and the mononuclear cells isolated from the colon and ileum expressing the lowest levels. While a significant frequency of pDCs and mDCs express Siglec-1/Siglec-3, a much lower frequency expresses CD200, CD200R and Mincle in PBMCs from rhesus macaques. The mAb against CD200 and CD200R but not Mincle appear to inhibit the infection of macrophage tropic SIV/SHIV in vitro. We conclude that these mAbs may have potential to be used as adjunctive therapeutic agents to control/inhibit SIV/HIV infection. PMID:26468886

  2. PSD-95 regulates D1 dopamine receptor resensitization, but not receptor-mediated Gs-protein activation

    Institute of Scientific and Technical Information of China (English)

    Peihua Sun; Jingru Wang; Weihua Gu; Wei Cheng; Guo-zhang Jin; Eitan Friedman; Jie Zheng; Xuechu Zhen

    2009-01-01

    The present study aims to define the role of postsynaptic density (PSD)-95 in the regulation of dopamine (DA) receptor function. We found that PSD-95 physically associates with either D1 or D2 DA receptors in co-transfected HEK-293 cells. Stimulation of DA receptors altered the association between D1 receptor and PSD-95 in a time-depen-dent manner. Functional assays indicated that PSD-95 co-expression did not affect D1 receptor-stimulated cAMP pro-duction, Gs-protein activation or receptor desensitization. However, PSD-95 accelerated the recovery of internalized membrane receptors by promoting receptor recycling, thus resulting in enhanced resensitization of internalized D1 receptors. Our results provide a novel mechanism for regulating DA receptor recycling that may play an important role in postsynaptic DA functional modulation and synaptic neuroplasticity.

  3. P2X7 receptor-mediated PARP1 activity regulates astroglial death in the rat hippocampus following status epilepticus

    Directory of Open Access Journals (Sweden)

    Ji Yang eKim

    2015-09-01

    Full Text Available Poly(ADP-ribose polymerase-1 (PARP1 plays a regulatory role in apoptosis, necrosis, and other cellular processes after injury. Recently, we revealed that PARP1 regulates the differential neuronal/astroglial responses to pilocarpine-induced status epilepticus (SE in the distinct brain regions. In addition, P2X7 receptor (P2X7R, an ATP-gated ion channel, activation accelerates astroglial apoptosis, while it attenuates clasmatodendrosis (lysosome-derived autophagic astroglial death. Therefore, we investigated whether P2X7R regulates regional specific astroglial PARP1 expression/activation in response to SE. In the present study, P2X7R activation exacerbates SE-induced astroglial apoptosis, while P2X7R inhibition attenuates it accompanied by increasing PARP1 activity in the molecular layer of the dentate gyrus following SE. In the CA1 region, however, P2X7R inhibition deteriorates SE-induced clasmatodendrosis via PARP1 activation following SE. Taken together, our findings suggest that P2X7R function may affect SE-induced astroglial death by regulating PARP1 activation/expression in regional-specific manner. Therefore, the selective modulation of P2X7R-mediated PARP1 functions may be a considerable strategy for controls in various types of cell deaths.

  4. Presynaptic Adenosine Receptor-Mediated Regulation of Diverse Thalamocortical Short-Term Plasticity in the Mouse Whisker Pathway.

    Science.gov (United States)

    Ferrati, Giovanni; Martini, Francisco J; Maravall, Miguel

    2016-01-01

    Short-term synaptic plasticity (STP) sets the sensitivity of a synapse to incoming activity and determines the temporal patterns that it best transmits. In "driver" thalamocortical (TC) synaptic populations, STP is dominated by depression during stimulation from rest. However, during ongoing stimulation, lemniscal TC connections onto layer 4 neurons in mouse barrel cortex express variable STP. Each synapse responds to input trains with a distinct pattern of depression or facilitation around its mean steady-state response. As a result, in common with other synaptic populations, lemniscal TC synapses express diverse rather than uniform dynamics, allowing for a rich representation of temporally varying stimuli. Here, we show that this STP diversity is regulated presynaptically. Presynaptic adenosine receptors of the A1R type, but not kainate receptors (KARs), modulate STP behavior. Blocking the receptors does not eliminate diversity, indicating that diversity is related to heterogeneous expression of multiple mechanisms in the pathway from presynaptic calcium influx to neurotransmitter release.

  5. Presynaptic adenosine receptor-mediated regulation of diverse thalamocortical short-term plasticity in the mouse whisker pathway

    Directory of Open Access Journals (Sweden)

    Giovanni eFerrati

    2016-02-01

    Full Text Available Short-term synaptic plasticity (STP sets the sensitivity of a synapse to incoming activity and determines the temporal patterns that it best transmits. In driver thalamocortical (TC synaptic populations, STP is dominated by depression during stimulation from rest. However, during ongoing stimulation, lemniscal TC connections onto layer 4 neurons in mouse barrel cortex express variable STP. Each synapse responds to input trains with a distinct pattern of depression or facilitation around its mean steady-state response. As a result, in common with other synaptic populations, lemniscal TC synapses express diverse rather than uniform dynamics, allowing for a rich representation of temporally varying stimuli. Here we show that this STP diversity is regulated presynaptically. Presynaptic adenosine receptors of the A1R type, but not kainate receptors, modulate STP behavior. Blocking the receptors does not eliminate diversity, indicating that diversity is related to heterogeneous expression of multiple mechanisms in the pathway from presynaptic calcium influx to neurotransmitter release.

  6. Presynaptic Adenosine Receptor-Mediated Regulation of Diverse Thalamocortical Short-Term Plasticity in the Mouse Whisker Pathway

    Science.gov (United States)

    Ferrati, Giovanni; Martini, Francisco J.; Maravall, Miguel

    2016-01-01

    Short-term synaptic plasticity (STP) sets the sensitivity of a synapse to incoming activity and determines the temporal patterns that it best transmits. In “driver” thalamocortical (TC) synaptic populations, STP is dominated by depression during stimulation from rest. However, during ongoing stimulation, lemniscal TC connections onto layer 4 neurons in mouse barrel cortex express variable STP. Each synapse responds to input trains with a distinct pattern of depression or facilitation around its mean steady-state response. As a result, in common with other synaptic populations, lemniscal TC synapses express diverse rather than uniform dynamics, allowing for a rich representation of temporally varying stimuli. Here, we show that this STP diversity is regulated presynaptically. Presynaptic adenosine receptors of the A1R type, but not kainate receptors (KARs), modulate STP behavior. Blocking the receptors does not eliminate diversity, indicating that diversity is related to heterogeneous expression of multiple mechanisms in the pathway from presynaptic calcium influx to neurotransmitter release. PMID:26941610

  7. RhoA and Rac1 GTPases Differentially Regulate Agonist-Receptor Mediated Reactive Oxygen Species Generation in Platelets

    Science.gov (United States)

    Akbar, Huzoor; Duan, Xin; Saleem, Saima; Davis, Ashley K.; Zheng, Yi

    2016-01-01

    Agonist induced generation of reactive oxygen species (ROS) by NADPH oxidases (NOX) enhances platelet aggregation and hence the risk of thrombosis. RhoA and Rac1 GTPases are involved in ROS generation by NOX in a variety of cells, but their roles in platelet ROS production remain unclear. In this study we used platelets from RhoA and Rac1 conditional knockout mice as well as human platelets treated with Rhosin and NSC23767, rationally designed small molecule inhibitors of RhoA and Rac GTPases, respectively, to better define the contributions of RhoA and Rac1 signaling to ROS generation and platelet activation. Treatment of platelets with Rhosin inhibited: (a) U46619 induced activation of RhoA; (b) phosphorylation of p47phox, a critical component of NOX; (c) U46619 or thrombin induced ROS generation; (d) phosphorylation of myosin light chain (MLC); (e) platelet shape change; (f) platelet spreading on immobilized fibrinogen; and (g) release of P-selectin, secretion of ATP and aggregation. Conditional deletion of RhoA or Rac1 gene inhibited thrombin induced ROS generation in platelets. Addition of Y27632, a RhoA inhibitor, NSC23766 or Phox-I, an inhibitor of Rac1-p67phox interaction, to human platelets blocked thrombin induced ROS generation. These data suggest that: (a) RhoA/ROCK/p47phox signaling axis promotes ROS production that, at least in part, contributes to platelet activation in conjunction with or independent of the RhoA/ROCK mediated phosphorylation of MLC; and (b) RhoA and Rac1 differentially regulate ROS generation by inhibiting phosphorylation of p47phox and Rac1-p67phox interaction, respectively. PMID:27681226

  8. Expression of the Inhibitory CD200 Receptor Is Associated with Alternative Macrophage Activation

    NARCIS (Netherlands)

    N. Koning; M. van Eijk; W. Pouwels; M.S.M. Brouwer; D. Voehringer; I. Huitinga; R.M. Hoek; G. Raes; J. Hamann

    2010-01-01

    Classical macrophage activation is inhibited by the CD200 receptor (CD200R). Here, we show that CD200R expression was specifically induced on human in vitro polarized macrophages of the alternatively activated M2a subtype, generated by incubation with IL-4 or IL-13. In mice, peritoneal M2 macrophage

  9. Reduced Mechanical Stretch Induces Enhanced Endothelin B Receptor-mediated Contractility via Activation of Focal Adhesion Kinase and Extra Cellular-regulated Kinase 1/2 in Cerebral Arteries from Rat

    DEFF Research Database (Denmark)

    Rasmussen, Marianne N P; Spray, Stine; Skovsted, Gry F;

    2016-01-01

    Cerebral ischaemia results in enhanced endothelin B (ETB ) receptor-mediated contraction and receptor protein expression in the affected cerebrovascular smooth muscle cells (SMC). Organ culture of cerebral arteries is a method to induce similar alterations in ETB receptor expression. We hypothesize...... ETB receptor agonist sarafotoxin 6c. The involvement of extracellular regulated kinase (ERK) 1/2 and focal adhesion kinase (FAK) were studied by their specific inhibitors U0126 and PF-228, respectively. Compared to their stretched counterparts, un-stretched MCA segments showed a significantly...

  10. A new insight into viral proteins as Immunomodulatory therapeutic agents: KSHV vOX2 a homolog of human CD200 as a potent anti-inflammatory protein

    Science.gov (United States)

    Mousavinezhad-Moghaddam, Maryam; Amin, Abbas Ali; Rafatpanah, Houshang; Rezaee, Seyed Abdol Rahim

    2016-01-01

    The physiologic function of the immune system is defense against infectious microbes and internal tumour cells, Therefore, need to have precise modulatory mechanisms to maintain the body homeostasis. The mammalian cellular CD200 (OX2)/CD200R interaction is one of such modulatory mechanisms in which myeloid and lymphoid cells are regulated. CD200 and CD200R molecules are membrane proteins that their immunomodulatory effects are able to suppress inflammatory responses, particularly in the privilege sites such as CNS and eyes. Kaposi’s sarcoma-associated herpesvirus (KSHV), encodes a wide variety of immunoregulatory proteins which play central roles in modulating inflammatory and anti-inflammatory responses in favour of virus dissemination. One such protein is a homologue of the, encoded by open reading frame (ORF) K14 and therefore called vOX2. Based on its gene expression profile during the KSHV life cycle, it is hypothesised that vOX2 modulates host inflammatory responses. Moreover, it seems that vOX2 involves in cell adhesion and modulates innate immunity and promotes Th2 immune responses. In this review the activities of mammalian CD200 and KSHV CD200 in cell adhesion and immune system modulation are reviewed in the context of potential therapeutic agents. PMID:27096058

  11. A Truncated form of CD200 (CD200S) Expressed on Glioma Cells Prolonged Survival in a Rat Glioma Model by Induction of a Dendritic Cell-Like Phenotype in Tumor-Associated Macrophages12

    Science.gov (United States)

    Kobayashi, Kana; Yano, Hajime; Umakoshi, Akihiro; Matsumoto, Shirabe; Mise, Ayano; Funahashi, Yu; Ueno, Yoshitomo; Kamei, Yoshiaki; Takada, Yasutsugu; Kumon, Yoshiaki; Ohnishi, Takanori; Tanaka, Junya

    2016-01-01

    CD200 induces immunosuppression in myeloid cells expressing its receptor CD200R, which may have consequences for tumor immunity. We found that human carcinoma tissues express not only full-length CD200 (CD200L) but also its truncated form, CD200S. Although CD200S is reported to antagonize the immunosuppressive actions of CD200L, the role of CD200S in tumor immunity has never been investigated. We established rat C6 glioma cell lines that expressed either CD200L or CD200S; the original C6 cell line did not express CD200 molecules. The cell lines showed no significant differences in growth. Upon transplantation into the neonatal Wistar rat forebrain parenchyma, rats transplanted with C6-CD200S cells survived for a significantly longer period than those transplanted with the original C6 and C6-CD200L cells. The C6-CD200S tumors were smaller than the C6-CD200L or C6-original tumors, and many apoptotic cells were found in the tumor cell aggregates. Tumor-associated macrophages (TAMs) in C6-CD200S tumors displayed dendritic cell (DC)-like morphology with multiple processes and CD86 expression. Furthermore, CD3+, CD4+ or CD8+ cells were more frequently found in C6-CD200S tumors, and the expression of DC markers, granzyme, and perforin was increased in C6-CD200S tumors. Isolated TAMs from original C6 tumors were co-cultured with C6-CD200S cells and showed increased expression of DC markers. These results suggest that CD200S activates TAMs to become DC-like antigen presenting cells, leading to the activation of CD8+ cytotoxic T lymphocytes, which induce apoptotic elimination of tumor cells. The findings on CD200S action may provide a novel therapeutic modality for the treatment of carcinomas. PMID:27108386

  12. A Truncated form of CD200 (CD200S Expressed on Glioma Cells Prolonged Survival in a Rat Glioma Model by Induction of a Dendritic Cell-Like Phenotype in Tumor-Associated Macrophages

    Directory of Open Access Journals (Sweden)

    Kana Kobayashi

    2016-04-01

    Full Text Available CD200 induces immunosuppression in myeloid cells expressing its receptor CD200R, which may have consequences for tumor immunity. We found that human carcinoma tissues express not only full-length CD200 (CD200L but also its truncated form, CD200S. Although CD200S is reported to antagonize the immunosuppressive actions of CD200L, the role of CD200S in tumor immunity has never been investigated. We established rat C6 glioma cell lines that expressed either CD200L or CD200S; the original C6 cell line did not express CD200 molecules. The cell lines showed no significant differences in growth. Upon transplantation into the neonatal Wistar rat forebrain parenchyma, rats transplanted with C6-CD200S cells survived for a significantly longer period than those transplanted with the original C6 and C6-CD200L cells. The C6-CD200S tumors were smaller than the C6-CD200L or C6-original tumors, and many apoptotic cells were found in the tumor cell aggregates. Tumor-associated macrophages (TAMs in C6-CD200S tumors displayed dendritic cell (DC-like morphology with multiple processes and CD86 expression. Furthermore, CD3+, CD4+ or CD8+ cells were more frequently found in C6-CD200S tumors, and the expression of DC markers, granzyme, and perforin was increased in C6-CD200S tumors. Isolated TAMs from original C6 tumors were co-cultured with C6-CD200S cells and showed increased expression of DC markers. These results suggest that CD200S activates TAMs to become DC-like antigen presenting cells, leading to the activation of CD8+ cytotoxic T lymphocytes, which induce apoptotic elimination of tumor cells. The findings on CD200S action may provide a novel therapeutic modality for the treatment of carcinomas.

  13. Tumor-derived vaccines containing CD200 inhibit immune activation: implications for immunotherapy.

    Science.gov (United States)

    Xiong, Zhengming; Ampudia-Mesias, Elisabet; Shaver, Rob; Horbinski, Craig M; Moertel, Christopher L; Olin, Michael R

    2016-09-01

    There are over 400 ongoing clinical trials using tumor-derived vaccines. This approach is especially attractive for many types of brain tumors, including glioblastoma, yet so far the clinical response is highly variable. One contributor to poor response is CD200, which acts as a checkpoint blockade, inducing immune tolerance. We demonstrate that, in response to vaccination, glioma-derived CD200 suppresses the anti-tumor immune response. In contrast, a CD200 peptide inhibitor that activates antigen-presenting cells overcomes immune tolerance. The addition of the CD200 inhibitor significantly increased leukocyte infiltration into the vaccine site, cytokine and chemokine production, and cytolytic activity. Our data therefore suggest that CD200 suppresses the immune system's response to vaccines, and that blocking CD200 could improve the efficacy of cancer immunotherapy. PMID:27485078

  14. Melanoma Cell Expression of CD200 Inhibits Tumor Formation and Lung Metastasis via Inhibition of Myeloid Cell Functions

    OpenAIRE

    Talebian, Fatemeh; Liu, Jin-Qing; Liu, Zhenzhen; Khattabi, Mazin; He, Yukai; Ganju, Ramesh; Bai, Xue-feng

    2012-01-01

    CD200 is a cell surface glycoprotein that functions through engaging CD200 receptor on cells of the myeloid lineage and inhibits their functions. Expression of CD200 has been implicated in a variety of human cancer cells including melanoma cells and has been thought to play a protumor role. To investigate the role of cancer cell expression of CD200 in tumor formation and metastasis, we generated CD200-positive and CD200-negative B16 melanoma cells. Subcutaneous injection of CD200-positive B16...

  15. Impact of CD200-Fc on dendritic cells in lupus-prone NZB/WF1 mice

    Science.gov (United States)

    Yin, Yufeng; Zhao, Lidan; Zhang, Fengchun; Zhang, Xuan

    2016-01-01

    Abnormal expression of CD200/CD200R1 may contribute to the immunologic abnormalities in patients with systemic lupus erythematosus (SLE). This study aimed to assess the function of CD200/CD200R1and impact of CD200-Fc on dendritic cells in lupus-prone NZB/WF1 mice. Female NZB/WF1 mice were treated with CD200-Fc or control for 4 weeks. Plasma samples were collected to measure autoantibody levels. The expression levels of CD200/CD200R1 in peripheral blood mononuclear cells (PBMCs) and splenocytes were examined. The percentage of CD200/CD200R1-positive cells in splenocytes from NZB/WF1 mice was lower than that of C57BL/6 mice (p lupus. PMID:27545083

  16. The CD200 tolerance-signaling molecule and its receptor, CD200R1, are expressed in human placental villus trophoblast and in peri-implant decidua by 5 weeks' gestation.

    Science.gov (United States)

    Clark, David A; Arredondo, Jorge L; Dhesy-Thind, Sukhbinder

    2015-11-01

    CD200 expression in murine trophoblast and decidua prevents semi-allogeneic and LPS-induced abortions by binding to CD200 receptor-bearing cells to suppress NK activity, induces IDO in macrophages, and promotes the generation of regulatory T cell subsets. CD200 and its receptor CD200R1 reported in 7-9 weeks' gestation human villus trophoblasts are reduced in spontaneous abortion syncytiotrophoblasts. By specific antibody staining, we find that both CD200 and CD200R1 are expressed even earlier, by 5 weeks' gestation, by villus trophoblasts and by decidual cells. Expression of CD200 was validated using two independent antibodies. CD200-CD200R1 signaling may be required for human pregnancy success. PMID:26123445

  17. Melanoma cell expression of CD200 inhibits tumor formation and lung metastasis via inhibition of myeloid cell functions.

    Directory of Open Access Journals (Sweden)

    Fatemeh Talebian

    Full Text Available CD200 is a cell surface glycoprotein that functions through engaging CD200 receptor on cells of the myeloid lineage and inhibits their functions. Expression of CD200 has been implicated in a variety of human cancer cells including melanoma cells and has been thought to play a protumor role. To investigate the role of cancer cell expression of CD200 in tumor formation and metastasis, we generated CD200-positive and CD200-negative B16 melanoma cells. Subcutaneous injection of CD200-positive B16 melanoma cells inhibited tumor formation and growth in C57BL/6 mice but not in Rag1⁻/⁻C57BL/6 mice. However, i.v. injection of CD200-positive B16 melanoma cells dramatically inhibited tumor foci formation in the lungs of both C57BL/6 and Rag1⁻/⁻C57BL6 mice. Flow cytometry analysis revealed higher expression of CD200R in Gr1⁺ myeloid cells in the lung than in peripheral myeloid cells. Depletion of Gr1⁺ cells or stimulation of CD200R with an agonistic antibody in vivo dramatically inhibited tumor foci formation in the lungs. In addition, treatment with tumor antigen specific CD4 or CD8 T cells or their combination yielded a survival advantage for CD200 positive tumor bearing mice over mice bearing CD200-negative tumors. Taken together, we have revealed a novel role for CD200-CD200R interaction in inhibiting tumor formation and metastasis. Targeting CD200R may represent a novel approach for cancer immunotherapy.

  18. G-protein-coupled Receptor Kinase-interacting Proteins Inhibit Apoptosis by Inositol 1,4,5-Triphosphate Receptor-mediated Ca2+ Signal Regulation*

    OpenAIRE

    Zhang, Songbai; Hisatsune, Chihiro; Matsu-ura, Toru; Mikoshiba, Katsuhiko

    2009-01-01

    The inositol 1,4,5-trisphosphate (IP3) receptor (IP3R) is an intracellular IP3-gated calcium (Ca2+) release channel and plays important roles in regulation of numerous Ca2+-dependent cellular responses. Many intracellular modulators and IP3R-binding proteins regulate the IP3R channel function. Here we identified G-protein-coupled receptor kinase-interacting proteins (GIT), GIT1 and GIT2, as novel IP3R-binding proteins. We found that both GIT1 and GIT2 directly bind to all three subtypes of IP...

  19. Protein Phosphatase 2Cβl Regulates Human Pregnane X Receptor-Mediated CYP3A4 Gene Expression in HepG2 Liver Carcinoma Cells

    OpenAIRE

    Pondugula, Satyanarayana R.; Tong, Alexander A.; Wu, Jing; Cui, Jimmy; Chen, Taosheng

    2010-01-01

    The human pregnane X receptor (hPXR) regulates the expression of CYP3A4, which plays a vital role in hepatic drug metabolism and has considerably reduced expression levels in proliferating hepatocytes. We have recently shown that cyclin-dependent kinase 2 (CDK2) negatively regulates hPXR-mediated CYP3A4 gene expression. CDK2 can be dephosphorylated and inactivated by protein phosphatase type 2C beta isoform long (PP2Cβl), a unique phosphatase that was originally cloned from human liver. In th...

  20. The Role of Janus Kinase (JAK)-3 in Regulating Toll-Like Receptor-Mediated Inflammatory Cytokine Production in Innate Immune Cells

    OpenAIRE

    Wang, Huizhi; Brown, Jonathan; Gao, Shegan; Liang, Shuang; Jotwani, Ravi; Zhou, Huaxin; Suttles, Jill; Scott, David; Lamont, Richard J.

    2013-01-01

    The role of Janus kinase (JAK)-3 in TLR-mediated innate immune responses is poorly understood, although the suppressive function of JAK3 inhibition in adaptive immune response has been well studied. In this study, we found that JAK3 inhibition enhanced TLR-mediated immune responses by differentially regulating pro- and anti- inflammatory cytokine production in innate immune cells. Specifically, JAK3 inhibition by pharmacological inhibitors or specific siRNA, or JAK3 gene knockout resulted in ...

  1. The Hypolipidemic Agent Guggulsterone Regulates the Expression of Human Bile Salt Export Pump: Dominance of Transactivation over Farsenoid X Receptor-Mediated Antagonism

    OpenAIRE

    Deng, Ruitang; Yang, Dongfang; Radke, Amy; Yang, Jian; Yan, Bingfang

    2006-01-01

    Conversion of cholesterol to bile acids in the liver is initiated by the rate-limiting enzyme cholesterol 7α-hydroxylase (CYP7A1) and excretion of bile acids from the liver is mediated by the bile salt export pump (BSEP). The expression of CYP7A1 and BSEP is coordinately regulated by a negative feedback and positive feed-forward mechanism, respectively, through bile acid-mediated activation of farsenoid X receptor (FXR). It is well established that hypolipidemic agent guggulsterone is an FXR ...

  2. The anti-inflammatory glycoprotein, CD200, restores neurogenesis and enhances amyloid phagocytosis in a mouse model of Alzheimer's disease.

    Science.gov (United States)

    Varnum, Megan M; Kiyota, Tomomi; Ingraham, Kaitlin L; Ikezu, Seiko; Ikezu, Tsuneya

    2015-11-01

    Cluster of Differentiation-200 (CD200) is an anti-inflammatory glycoprotein expressed in neurons, T cells, and B cells, and its receptor is expressed on glia. Both Alzheimer's disease patients and mouse models display age-related or amyloid-β peptide (Aβ)-induced reductions in CD200. The goal of this study was to determine if neuronal CD200 expression restores hippocampal neurogenesis and reduces Aβ in the amyloid precursor protein mouse model. Amyloid precursor protein and wild-type mice were injected at 6 months of age with an adeno-associated virus expressing CD200 into the hippocampus and sacrificed at 12 months. CD200 expression restored neural progenitor cell proliferation and differentiation in the subgranular and granular cell layers of the dentate gyrus and reduced diffuse but not thioflavin-S(+) plaques in the hippocampus. In vitro studies demonstrated that CD200-stimulated microglia increased neural differentiation of neural stem cells and enhanced axon elongation and dendrite number. CD200 also enhanced Aβ uptake by microglia. These data indicate that CD200 is capable of enhancing microglia-mediated Aβ clearance and neural differentiation and has potential as a therapeutic for Alzheimer's disease.

  3. Vascular endothelin ET(B) receptor-mediated contraction requires phosphorylation of ERK1/2 proteins

    DEFF Research Database (Denmark)

    Luo, Guogang; Jamali, Roya; Cao, Yong-Xiao;

    2006-01-01

    RNA and protein expressions. The endothelin ET(B) receptor-mediated contraction was associated with increase in phosphorylation of extracellular regulation kinase 1 and 2 (ERK1/2) proteins and elevated levels of intracellular calcium. The elevation curve of intracellular calcium consisted of two phases: one rapid...... and one sustained. Inhibition of ERK1/2 phosphorylation by SB386023 or blockage of calcium channels by nifedipine significantly reduced the endothelin ET(B) receptor-mediated contraction (P..., phosphorylation of ERK1/2 proteins and elevation of intracellular calcium level are required for endothelin ET(B) receptor-mediated contraction in rat mesenteric artery....

  4. Increased Expression of CD200 on Circulating CD11b+ Monocytes in Patients with Neovascular Age-related Macular Degeneration

    DEFF Research Database (Denmark)

    Singh, Amardeep; Falk, Mads K; Hviid, Thomas V F;

    2013-01-01

    the ligand and the receptor are expressed on a broad spectrum of cell types, we set out to study the expression of CD200 and CD200R on CD11b+ monocytes, granulocytes, and subsets of T lymphocytes. DESIGN: Prospective, case-control study. PARTICIPANTS: The study population consisted of 62 patients......, and detailed retinal imaging was performed: fundus autofluorescence imaging, digital color fundoscopy, and spectral-domain optical coherence tomography. Fluorescein and indocyanine green angiography were performed in patients with suspected neovascular AMD. Visual acuity was measured in both eyes. Fresh venous...... blood was obtained and stained with monoclonal antibodies and analyzed using flow cytometry within 6 hours of phlebotomy. MAIN OUTCOME MEASURES: The percentage of CD11b+ monocytes, granulocytes, and CD4+/CD8+ T lymphocytes positive for CD200 or CD200R in patients and controls, respectively. RESULTS...

  5. Brain Innate Immunity in the Regulation of Neuroinflammation: Therapeutic Strategies by Modulating CD200-CD200R Interaction Involve the Cannabinoid System

    OpenAIRE

    Hernangómez, Miriam; Carrillo-Salinas, Francisco J.; Mecha, Miriam; Correa, Fernando; Mestre, Leyre; Loría, Frida; Feliú, Ana; Docagne, Fabian; Guaza, Carmen

    2014-01-01

    The central nervous system (CNS) innate immune response includes an arsenal of molecules and receptors expressed by professional phagocytes, glial cells and neurons that is involved in host defence and clearance of toxic and dangerous cell debris. However, any uncontrolled innate immune responses within the CNS are widely recognized as playing a major role in the development of autoimmune disorders and neurodegeneration, with multiple sclerosis (MS) Alzheimer's disease (AD) being primary exam...

  6. Graft-infiltrating cells expressing a CD200 transgene prolong allogeneic skin graft survival in association with local increases in Foxp3(+)Treg and mast cells.

    Science.gov (United States)

    Gorczynski, Reginald M; Chen, Zhiqi; Khatri, Ismat; Yu, Kai

    2011-12-01

    Expression of the molecule CD200 has been reported to increase allograft survival by suppression of inflammation and acquired immunity. In previous studies we have shown that increased skin and cardiac allograft survival in transgenic mice over-expressing CD200 (CD200(tg)) occurs in association with increased intra-graft expression of mRNAs for genes associated with altered T cell subset differentiation. We investigated changes in graft-infiltrating cells, Treg and mast cells in skin grafts post transplantation into control or CD200(tg) mice, using focused gene array and real-time PCR to assess altered gene expression, and FACS, immunohistology and MLC to determine numbers/function of those cells. Graft-infiltrating cells isolated from CD200(tg) recipients suppressed induction of CTL from control lymph node cells in vitro, and contained increased numbers of infiltrating, non-degranulating, mast cells and Foxp3(+)Treg. Mast cells were also evident in graft tissue of control animals, but there these cells showed evidence for degranulation, and fewer Foxp3(+)Treg were present than was the case of CD200(tg) mice. The infusion of a competitive inhibitor of CD200:CD200R interactions, CD200(tr), at high concentrations (50μg/mouse iv) caused rapid rejection of grafts in CD200(tg) mice, mast cell degranulation within graft tissue, and a decrease in Treg infiltrates. These effects were attenuated by simultaneous infusion of the mast cell stabilizer, sodium cromoglycate. We conclude that CD200 expression contributes to graft prolongation through local suppression of mast cell degranulation, attraction/expansion of Treg, and attenuation of T cell effector activation. PMID:21801836

  7. Reduced Dendritic Cells Expressing CD200R1 in Children with Inflammatory Bowel Disease: Correlation with Th17 and Regulatory T Cells.

    Science.gov (United States)

    Elshal, Mohamed F; Aldahlawi, Alia M; Saadah, Omar I; McCoy, J Philip

    2015-12-04

    Loss of tolerance of the adaptive immune system towards indigenous flora contributes to the development of inflammatory bowel diseases (IBD). Defects in dendritic cell (DC)-mediated innate and adoptive immune responses are conceivable. The aim of this study was to investigate the expression of the inhibitory molecules CD200R1 and their ligand CD200 on DCs, to clarify the role of the DCs in the pathogenesis of IBD. Thirty-seven pediatric IBD patients (23 with Crohn's disease (CD) and 14 with ulcerative colitis (UC)) with mean age 13.25 ± 2.9 years were included. Fourteen age-matched healthy pediatric volunteers (five males and nine females) served as a control group (HC). The percentage of CD11c⁺ myeloid dendritic cells (mDCs) and CD123⁺ plasmacytoid DCs (pDCs) expressing CD200R1 and CD200 were evaluated in peripheral blood using flow cytometry and were correlated with routine biochemical, serological markers, serum levels of cytokines and with the percentages of circulating regulatory T cells (Treg) and CD4⁺ producing IL-17 (Th17). IBD patients showed a significant decrease in the percentage of pDCs and mDCs expressing CD200R1 compared to that of HC. Patients with UC showed increased expressions of the CD200 molecule on pDCs as compared to HC. DCs expressing CD200R1 were found to be correlated positively with Treg and negatively with TH17 and erythrocyte sedimentation rate (ESR). Our findings suggest that IBD is associated with dysregulation in the CD200R1/CD200 axis and that the decrease in DCs expressing CD200R1 may contribute to the imbalance of Th17 and Treg cells and in the pathogenesis of IBD.

  8. Targeted gene delivery via N-acetylglucosamine receptor mediated endocytosis.

    Science.gov (United States)

    Singh, Bijay; Maharjan, Sushila; Kim, You-Kyoung; Jiang, Tai; Islam, Mohammad Ariful; Kang, Sang-Kee; Cho, Myung-Haing; Choi, Yun-Jaie; Cho, Chong-Su

    2014-11-01

    Receptor-mediated endocytosis is a promising approach of gene delivery into the target cells via receptor-ligand interaction. Vimentins at the cell surface are recently known to bind N-acetylglucosamine (GlcNAc) residue, therefore, the cell surfaces of vimentin-expressing cells could be targeted by using the GlcNAc residue as a specific ligand for receptor-mediated gene delivery. Here, we have developed polymeric gene delivery vectors, based on poly(ethylene oxide)(PEO) and poly(aspartamide), namely poly[(aspartamide)(diethylenetriamine)]-b-[PEO-(GlcNAc)] (PADPG) and poly[(aspartamide)(diethylenetriamine)]-b-[PEO] (PADP) to elucidate the efficiency of GlcNAc ligand for gene delivery through receptor mediated endocytosis. To determine the efficiency of these polymeric vectors for specific gene delivery, the DNA condensation ability of PADPG and PADP and the subsequent formation of polymeric nanoparticles were confirmed by gel retardation assay and transmission electron microscopy respectively. Both PADPG and PADP had lower cytotoxicity than polyethylenimine 25 K (PEI 25 K). However, their transfection efficiency was comparatively lower than PEI 25 K due to hydrophilic property of PEO in the vectors. To observe the stability of polymeric nanoparticles, the transfection of PADPG and PADP was carried out in the presence of serum. Favorably, the interfering effect of serum on the transfection efficiency of PADPG and PADP was also very low. Finally, when the cell specificity of these polymeric vectors was investigated, PADPG had high gene transfection in vimentin-expressing cells than vimentin-deficiency cells. The high transfection efficiency of PADPG was attributed to the GlcNAc in the polymeric vector which interact specifically with vimentin in the cells for the receptor-mediated endocytosis. The competitive inhibition assay further proved the receptor-mediated endocytosis of PADPG. Thus, this study demonstrates that conjugation of GlcNAc is an effective and rational

  9. Classical activation of microglia in CD200-deficient mice is a consequence of blood brain barrier permeability and infiltration of peripheral cells.

    Science.gov (United States)

    Denieffe, Stephanie; Kelly, Ronan J; McDonald, Claire; Lyons, Anthony; Lynch, Marina A

    2013-11-01

    The interaction between CD200, expressed on several cell types, and its receptor CD200R, expressed on cells of the myeloid lineage, has been shown to be an important factor in modulating inflammation in macrophage function in several conditions including colitis and arthritis. More recently its modulatory effect on microglial activation has been identified and CD200-deficiency has been associated with increased microglial activation accompanied by increased production of inflammatory cytokines. The response of glia prepared from CD200-deficient mice to stimuli like lipopolysaccharide (LPS) is markedly greater than the response of cells prepared from wildtype mice and, consistent with this, is the recent observation that expression of Toll-like receptor (TLR)4 and signalling through NFκB are increased in microglia prepared from CD200-deficient mice. Here we show that glia from CD200-deficient mice are also more responsive to interferon-γ (IFNγ) which triggers classical activation of microglia. We investigated the effects of CD200-deficiency in vivo and report that there is an increase in expression of several markers of microglial activation including tumor necrosis factor (TNF)-α, which is a hallmark of classically-activated microglia. These changes are accompanied by increased IFNγ, and the evidence suggests that this is produced by infiltrating cells including T cells and macrophages. We propose that these cells enter the brain as a consequence of increased blood brain barrier (BBB) permeability in CD200-deficient mice and that infiltration is assisted by increased expression of the chemokines, monocyte chemotactic protein-1 (MCP-1), IFNγ-induced protein-10 (IP-10) and RANTES. This may have implications in neurodegenerative diseases where BBB permeability is compromised.

  10. 苯丙酸诺龙对烫伤模型大鼠雄激素受体介导靶基因转录调控的影响%Effect of nandrolone phenylpropionate on androgen receptor-mediated transcriptional regulation of target genes in rat scald models

    Institute of Scientific and Technical Information of China (English)

    李凯; 岑瑛

    2015-01-01

    BACKGROUND:Moderate to severe burn and trauma, treatment of which has been paid equal attention to wound surface, is always a difficulty of clinical systemic treatment and has a poor prognosis. Anabolic hormones have acquired secure and good results in the treatment of burns in both animals and clinical patients. Although use of anabolic hormones is restricted by the doping management, but its androgen receptor and nuclear receptor coregulators are the newly emerging areas of interests in the field of gene regulation mechanism in recent years. OBJECTIVE:To investigate the effect of nandrolone phenylpropionate on androgen receptor-mediated transcriptional regulation of target gene in rat scald models. METHODS: Thirty-six rats were randomly divided into nandrolone phenylpropionate, model and control groups. In the nandrolone phenylpropionate and model groups, rats were subjected to a 20% total body surface area second-degree scald injury by hot water. Two days after model preparation, rats in these two groups were intramuscularly injected with nandrolone phenylpropionate and saline, once every other day, for a total of 21 days. RESULTS AND CONCLUSION:The gene expression levels of steroid receptor coactivator-1 and insulin-like growth factor 1 in the rat livers and gonads (testes, ovaries) were significantly different between the nandrolone phenylpropionate and model groups (P 0.05)。说明在不同组织不同生理病理条件下苯丙酸诺龙对类固醇受体辅助活化因子1、c-myc、胰岛素样生长因子1基因表达的作用是不同的。

  11. [Molecular physiology of receptor mediated endocytosis and its role in overcoming multidrug resistance].

    Science.gov (United States)

    Severin, E S; Posypanova, G A

    2011-06-01

    Receptor-mediated endocytosis plays important role in the selective uptake of proteins at the plasma membrane of eukaryotic cells. Endocytosis regulates many processes of cell signalling by controlling the number of functional receptors on the cell surface. The article reviews the mechanism of clathrin-dependent endocytosis and the possibility of using this phenomenon for the targeted delivery of drugs. Use of certain proteins as targeting component of drug delivery systems can significantly improve the selectivity of this drug, as well as to overcome the multidrug resistance of cells resulting from the activity of the ABC-transporters. PMID:21874867

  12. NMDA receptors mediate synaptic competition in culture.

    Directory of Open Access Journals (Sweden)

    Kevin She

    Full Text Available BACKGROUND: Activity through NMDA type glutamate receptors sculpts connectivity in the developing nervous system. This topic is typically studied in the visual system in vivo, where activity of inputs can be differentially regulated, but in which individual synapses are difficult to visualize and mechanisms governing synaptic competition can be difficult to ascertain. Here, we develop a model of NMDA-receptor dependent synaptic competition in dissociated cultured hippocampal neurons. METHODOLOGY/PRINCIPAL FINDINGS: GluN1 -/- (KO mouse hippocampal neurons lacking the essential NMDA receptor subunit were cultured alone or cultured in defined ratios with wild type (WT neurons. The absence of functional NMDA receptors did not alter neuron survival. Synapse development was assessed by immunofluorescence for postsynaptic PSD-95 family scaffold and apposed presynaptic vesicular glutamate transporter VGlut1. Synapse density was specifically enhanced onto minority wild type neurons co-cultured with a majority of GluN1 -/- neighbour neurons, both relative to the GluN1 -/- neighbours and relative to sister pure wild type cultures. This form of synaptic competition was dependent on NMDA receptor activity and not conferred by the mere physical presence of GluN1. In contrast to these results in 10% WT and 90% KO co-cultures, synapse density did not differ by genotype in 50% WT and 50% KO co-cultures or in 90% WT and 10% KO co-cultures. CONCLUSIONS/SIGNIFICANCE: The enhanced synaptic density onto NMDA receptor-competent neurons in minority coculture with GluN1 -/- neurons represents a cell culture paradigm for studying synaptic competition. Mechanisms involved may include a retrograde 'reward' signal generated by WT neurons, although in this paradigm there was no 'punishment' signal against GluN1 -/- neurons. Cell culture assays involving such defined circuits may help uncover the rules and mechanisms of activity-dependent synaptic competition in the

  13. The liver taxis of receptor mediated lactosaminated human growth hormone

    International Nuclear Information System (INIS)

    Radiography imaging is used to assess liver taxis mechanism of anti-dwarfism drug lactosaminated human growth hormone (L-rhGH). Both L-rhGH and rhGH labelled with 131I are used to study their biodistribution in animals (including rabbits, cocks and rats). The results show that L-rhGH is of specific hepatic targeting property, and the maximum hepatic concentration rate is 76.8%, which is two times of rhGH. Its hepatic binding is receptor mediated

  14. Asialoglycoprotein receptor mediated hepatocyte targeting - strategies and applications.

    Science.gov (United States)

    D'Souza, Anisha A; Devarajan, Padma V

    2015-04-10

    Hepatocyte resident afflictions continue to affect the human population unabated. The asialoglycoprotein receptor (ASGPR) is primarily expressed on hepatocytes and minimally on extra-hepatic cells. This makes it specifically attractive for receptor-mediated drug delivery with minimum concerns of toxicity. ASGPR facilitates internalization by clathrin-mediated endocytosis and exhibits high affinity for carbohydrates specifically galactose, N-acetylgalactosamine and glucose. Isomeric forms of sugar, galactose density and branching, spatial geometry and galactose linkages are key factors influencing ligand-receptor binding. Popular ligands for ASGPR mediated targeting are carbohydrate polymers, arabinogalactan and pullulan. Other ligands include galactose-bearing glycoproteins, glycopeptides and galactose modified polymers and lipids. Drug-ligand conjugates provide a viable strategy; nevertheless ligand-anchored nanocarriers provide an attractive option for ASGPR targeted delivery and are widely explored. The present review details various ligands and nanocarriers exploited for ASGPR mediated delivery of drugs to hepatocytes. Nanocarrier properties affecting ASGPR mediated uptake are discussed at length. The review also highlights the clinical relevance of ASGPR mediated targeting and applications in diagnostics. ASGPR mediated hepatocyte targeting provides great promise for improved therapy of hepatic afflictions.

  15. Cerebellar vermis H₂ receptors mediate fear memory consolidation in mice.

    Science.gov (United States)

    Gianlorenço, A C L; Riboldi, A M; Silva-Marques, B; Mattioli, R

    2015-02-01

    Histaminergic fibers are present in the molecular and granular layers of the cerebellum and have a high density in the vermis and flocullus. Evidence supports that the cerebellar histaminergic system is involved in memory consolidation. Our recent study showed that histamine injections facilitate the retention of an inhibitory avoidance task, which was abolished by pretreatment with an H2 receptor antagonist. In the present study, we investigated the effects of intracerebellar post training injections of H1 and H2 receptor antagonists as well as the selective H2 receptor agonist on fear memory consolidation. The cerebellar vermi of male mice were implanted with guide cannulae, and after three days of recovery, the inhibitory avoidance test was performed. Immediately after a training session, animals received a microinjection of the following histaminergic drugs: experiment 1, saline or chlorpheniramine (0.016, 0.052 or 0.16 nmol); experiment 2, saline or ranitidine (0.57, 2.85 or 5.07 nmol); and experiment 3, saline or dimaprit (1, 2 or 4 nmol). Twenty-four hours later, a retention test was performed. The data were analyzed using one-way analysis of variance (ANOVA) and Duncan's tests. Animals microinjected with chlorpheniramine did not show any behavioral effects at the doses that we used. Intra-cerebellar injection of the H2 receptor antagonist ranitidine inhibited, while the selective H2 receptor agonist dimaprit facilitated, memory consolidation, suggesting that H2 receptors mediate memory consolidation in the inhibitory avoidance task in mice.

  16. Somatostatin receptor-mediated imaging and therapy: basic science, current knowledge, limitations and future perspectives

    International Nuclear Information System (INIS)

    In vivo somatostatin receptor-mediated scintigraphy has proven to be a valuable method for the visualisation of neuroendocrine tumours and their metastases. A new application is the use of radiolabelled analogues for somatostatin receptor-mediated therapy. This paper presents a review on the basic science, historical background and current knowledge of somatostatin receptor subtypes and their expression in neuroendocrine tumours. New somatostatin analogues, new chelators, ''new'' radionuclides and combinations thereof are also discussed. Due attention is given to limitations and future perspectives of somatostatin receptor-mediated imaging and therapy. (orig.)

  17. Nicotine alpha 4 beta 2 receptor-mediated free calcium in an animal model of facial nucleus injury

    Institute of Scientific and Technical Information of China (English)

    Dawei Sun; Wenhai Sun; Yanqing Wang; Fugao Zhu; Rui Zhou; Yanjun Wang; Banghua Liu; Xiuming Wan; Huamin Liu

    2010-01-01

    Previous studies have demonstrated that the cholinergic system,via nicotinic receptors,regulates intracellular free calcium levels in the facial nucleus under normal physiological conditions.However,the regulation of nicotinic receptors on free calcium levels following facial nerve injury remains unclear.In the present study,an animal model of facial nerve injury was established,and changes in nicotinic receptor expression following facial nerve injury in rats were detected using reverse transcription polymerase chain reaction.Nicotinic receptor-mediated changes of free calcium levels following facial nucleus injury were determined by laser confocal microscopy.Results showed no significant difference in nicotinic receptor expression between the normal group and the affected facial nerve nucleus.The nicotinic receptor α4β2 subtype increased free calcium levels following facial nerve injury by promoting calcium transmembrane influx,and L-type voltage-gated calcium channel-mediated influx of calcium ions played an important role in promoting calcium transmembrane influx.The nicotinic receptor-mediated increase of free calcium levels following facial nerve injury provides an important mechanism for the repair of facial nerve injury.

  18. Fcγ receptor-mediated inflammation inhibits axon regeneration.

    Directory of Open Access Journals (Sweden)

    Gang Zhang

    Full Text Available Anti-glycan/ganglioside antibodies are the most common immune effectors found in patients with Guillain-Barré Syndrome, which is a peripheral autoimmune neuropathy. We previously reported that disease-relevant anti-glycan autoantibodies inhibited axon regeneration, which echo the clinical association of these antibodies and poor recovery in Guillain-Barré Syndrome. However, the specific molecular and cellular elements involved in this antibody-mediated inhibition of axon regeneration are not previously defined. This study examined the role of Fcγ receptors and macrophages in the antibody-mediated inhibition of axon regeneration. A well characterized antibody passive transfer sciatic nerve crush and transplant models were used to study the anti-ganglioside antibody-mediated inhibition of axon regeneration in wild type and various mutant and transgenic mice with altered expression of specific Fcγ receptors and macrophage/microglia populations. Outcome measures included behavior, electrophysiology, morphometry, immunocytochemistry, quantitative real-time PCR, and western blotting. We demonstrate that the presence of autoantibodies, directed against neuronal/axonal cell surface gangliosides, in the injured mammalian peripheral nerves switch the proregenerative inflammatory environment to growth inhibitory milieu by engaging specific activating Fcγ receptors on recruited monocyte-derived macrophages to cause severe inhibition of axon regeneration. Our data demonstrate that the antibody orchestrated Fcγ receptor-mediated switch in inflammation is one mechanism underlying inhibition of axon regeneration. These findings have clinical implications for nerve repair and recovery in antibody-mediated immune neuropathies. Our results add to the complexity of axon regeneration in injured peripheral and central nervous systems as adverse effects of B cells and autoantibodies on neural injury and repair are increasingly recognized.

  19. Enzyme induction and histopathology elucidate aryl hydrocarbon receptor-mediated versus non-aryl hydrocarbon receptor-mediated effects of Aroclor 1268 in American mink (Neovison vison).

    Science.gov (United States)

    Folland, William R; Newsted, John L; Fitzgerald, Scott D; Fuchsman, Phyllis C; Bradley, Patrick W; Kern, John; Kannan, Kurunthachalam; Zwiernik, Matthew J

    2016-03-01

    Polychlorinated biphenyl (PCB) concentrations reported in preferred prey and blubber of bottlenose dolphins from the Turtle-Brunswick River estuary (Georgia, USA) suggest the potential for adverse effects. However, PCBs in Turtle-Brunswick River estuary dolphins are primarily derived from Aroclor 1268, and predicting toxic effects of Aroclor 1268 is uncertain because of the mixture's unique composition and associated physiochemical characteristics. These differences suggest that toxicity benchmarks for other PCB mixtures may not be relevant to dolphins exposed to Aroclor 1268. American mink (Neovison vison) were used as a surrogate model for cetaceans to characterize mechanisms of action associated with Aroclor 1268 exposure. Mink share similarities in phylogeny and life history with cetaceans and are characteristically sensitive to PCBs, making them an attractive surrogate species for marine mammals in ecotoxicity studies. Adult female mink and a subsequent F1 generation were exposed to Aroclor 1268 through diet, and effects on enzyme induction, histopathology, thyroid hormone regulation, hematology, organ weights, and body condition index were compared to a negative control and a 3,3',4,4',5-pentachlorobiphenyl (PCB 126)-positive control. Aroclor 1268 dietary exposure concentrations ranged from 1.8 µg/g wet weight to 29 µg/g wet weight. Anemia, hypothyroidism, and hepatomegaly were observed in mink exposed to Aroclor 1268 beyond various dietary thresholds. Cytochrome P450 induction and squamous epithelial proliferation jaw lesions were low in Aroclor 1268 treatments relative to the positive control. Differences in enzyme induction and the development of squamous epithelial proliferation jaw lesions between Aroclor 1268 treatments and the positive control, coupled with effects observed in Aroclor 1268 treatments not observed in the positive control, indicate that mechanisms additional to the aryl hydrocarbon receptor-mediated pathway are associated with

  20. EGF-Receptor-Mediated Mammary Epithelial Cell Migration is Driven by Sustained ERK Signaling from Autocrine Stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Joslin, Elizabeth J.; Opresko, Lee; Wells, Alan; Wiley, H. S.; Lauffenburger, Douglas A.

    2007-10-15

    Aberrant expression of epidermal growth factor (EGF) receptor family ligands, as well as the receptors themselves, has been implicated in various types of cancers. EGF family ligands are synthesized as membrane-anchored proteins requiring proteolytic release to form the mature soluble factor. Despite the pathophysiological importance of autocrine systems, how the rate of protease-mediated ligand release quantitatively influences receptor-mediated signaling and consequent cell behavior is poorly understood. Therefore, we explored the relationship between autocrine EGF release rates and receptor-mediated ERK activation and migration in human mammary epithelial cells. A quantitative spectrum of EGF release rates was achieved using a set of chimeric transmembrane EGF ligand precursors modulated by the addition of the metalloprotease inhibitor batimastat. We found that ERK activation increased with increasing ligand release rates despite concomitant EGF receptor downregulation. Cell migration speed depended linearly on the steady-state phospho-ERK level obtained from either autocrine or exogenous ligand, but was much greater at any given phospho-ERK level for autocrine compared to exogenous stimulation. In contrast, cell proliferation rates were relatively constant across the various treatment conditions. Thus, in these cells, ERK-mediated migration stimulated by EGF receptor signaling is most sensitively regulated by autocrine ligand control mechanisms.

  1. Trypanosoma cruzi: antigen-receptor mediated endocytosis of antibody

    Directory of Open Access Journals (Sweden)

    Judith Abelha

    1981-06-01

    Full Text Available Trypanomastigote forms of Trypanosoma cruzi were derived from tissue culture and incubated with immune and non-immune human sera. All immune sera showed high titers of specific humoral antibodies of the IgM or the IgG type. Agglutination and swelling of parasites were observed after incubation at 37ºC, but many trypomastigotes remained free-swimming in the sera for two to three days. The quantitiy of immune serum capable of lysing a maximum of 10 x 10 [raised to the power of 6] sensitized red cells was not capable of lysing 4 x 10 [raised to the power of 3] tripomastigotes. Typically, the parasites underwent cyclical changes with the formation of clumps of amastigotes and the appearance of epimastigote forms. Multiplication of the parasites was observed in immune sera. Further, the infectivity of the parasites to susceptible mice was not lost. All sera used produced similar general effects on the growth of the parasite. The antibody bound to T. cruzi appeard to enter cells by antigen-receptor mediated endocytosis. The ferritin-conjugated antibody was internalized and delivered to phagolysosomes where they might be completely degraded to amino-acids. This seemed to be a coupled process by which the immunoglobulin is first bound to specific parasite surface receptor and then rapidly endocytosed by the cell.Formas tripomastigotas de Trypanosoma cruzi derivadas de cultura de tecido foram encubadas com soros humanos imunes e não-imunes.Todos os soros humanos usados tinham títulos elevados de anticorpos das classes IgM ou IgG. Aglutinação e entumescimento dos parasitos eram observados apos encubação a 37ºC mas muitos tripomastigotas permaneceram circulando livremente nos soros por dois a três dias. A quantidade de soro imune capaz de lisar um máximo de 10 x 10 [elevado a 6] hemácias sensibilizadas não foi capaz de lisar 4 x 10 [elevado a 3] tripomastigotas. Tipicamente, os parasitos apresentavam alterações cíclicas com formação de

  2. The influence of receptor-mediated interactions on reaction-diffusion mechanisms of cellular self-organisation.

    Science.gov (United States)

    Klika, Václav; Baker, Ruth E; Headon, Denis; Gaffney, Eamonn A

    2012-04-01

    Understanding the mechanisms governing and regulating self-organisation in the developing embryo is a key challenge that has puzzled and fascinated scientists for decades. Since its conception in 1952 the Turing model has been a paradigm for pattern formation, motivating numerous theoretical and experimental studies, though its verification at the molecular level in biological systems has remained elusive. In this work, we consider the influence of receptor-mediated dynamics within the framework of Turing models, showing how non-diffusing species impact the conditions for the emergence of self-organisation. We illustrate our results within the framework of hair follicle pre-patterning, showing how receptor interaction structures can be constrained by the requirement for patterning, without the need for detailed knowledge of the network dynamics. Finally, in the light of our results, we discuss the ability of such systems to pattern outside the classical limits of the Turing model, and the inherent dangers involved in model reduction. PMID:22072186

  3. P2X receptor-mediated ATP purinergic signaling in health and disease

    Directory of Open Access Journals (Sweden)

    Jiang LH

    2012-09-01

    Full Text Available Lin-Hua JiangSchool of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United KingdomAbstract: Purinergic P2X receptors are plasma membrane proteins present in a wide range of mammalian cells where they act as a cellular sensor, enabling cells to detect and respond to extracellular adenosine triphosphate (ATP, an important signaling molecule. P2X receptors function as ligand-gated Ca2+-permeable cationic channels that open upon ATP binding to elevate intracellular Ca2+ concentrations and cause membrane depolarization. In response to sustained activation, P2X receptors induce formation of a pore permeable to large molecules. P2X receptors also interact with distinct functional proteins and membrane lipids to form specialized signaling complexes. Studies have provided compelling evidence to show that such P2X receptor-mediated ATP-signaling mechanisms determine and regulate a growing number and diversity of important physiological processes, including neurotransmission, muscle contraction, and cytokine release. There is accumulating evidence to support strong causative relationships of altered receptor expression and function with chronic pain, inflammatory diseases, cancers, and other pathologies or diseases. Numerous high throughput screening drug discovery programs and preclinical studies have thus far demonstrated the proof of concepts that the P2X receptors are druggable targets and selective receptor antagonism is a promising therapeutics approach. This review will discuss the recent progress in understanding the mammalian P2X receptors with respect to the ATP-signaling mechanisms, physiological and pathophysiological roles, and development and preclinical studies of receptor antagonists.Keywords: extracellular ATP, ion channel, large pore, signaling complex, chronic pain, inflammatory diseases

  4. α1A-adrenergic receptor mediated pressor response to phenylephrine in anesthetized rat

    Institute of Scientific and Technical Information of China (English)

    XU Qi; ZHU Weizhong; L(U) Zhizhen; ZHANG Youyi; HAN Qide

    2004-01-01

    To determine which subtype of α1A-adrenergic receptors plays a role in the regulation of blood pressure, with α1A-adrenergic receptor-mediated vasoconstriction in perfused hindlimb as a control, we compared the inhibitory effects of various α1A-adrenergic receptor selective antagonists on the vasopressure responses to phenylephrine between the mean arterial pressure and hindlimb perfusion pressure in anesthetized rats. In Normotensive Wistar rats, the results showed that the inhibitory effects (dose ratios of ED50, Dr) of α1A-adrenoceptor selective antagonist (prazosin, Dr 13.5 ± 3.6 vs.15.1 ± 4.3, n = 11), α1A-adrenoceptor selective antagonist (5- methyl-urapidil, Dr 2.4 ± 0.9 vs. 3.7 ± 2.3, n = 12; RS-17053, Dr 3.2 ± 1.6 vs. 4.4 ± 3.3, n =12) and α1D- adrenoceptor selective antagonist (BMY7378, Dr 1.9 ± 0.9 vs. 2.2 ± 0.8, n = 8) on phenylephrine- induced increases of perfusion pressure in the autoperfused femoral beds were the same as that in the mean arterial blood pressure in normotensive Wistar rats. The inhibitory effects of antagonists (RS-17053, Dr 3.4 ± 0.6 vs. 4.3 ± 0.9, n = 5; BMY7378, Dr 1.7±0.5 vs. 1.7 ± 0.5, n = 8) in spontaneous hypertensive rats were similar with the Wistar rats. These results suggest that the mean arterial pressure induced by phenylephrine was mainly mediated by α1A-adrenergic receptor in both the anesthetized Wistar rats and spontaneous hypertensive rats.

  5. Direct muscarinic and nicotinic receptor-mediated excitation of rat medial vestibular nucleus neurons in vitro

    Science.gov (United States)

    Phelan, K. D.; Gallagher, J. P.

    1992-01-01

    We have utilized intracellular recording techniques to investigate the cholinoceptivity of rat medial vestibular nucleus (MVN) neurons in a submerged brain slice preparation. Exogenous application of the mixed cholinergic agonists, acetylcholine (ACh) or carbachol (CCh), produced predominantly membrane depolarization, induction of action potential firing, and decreased input resistance. Application of the selective muscarinic receptor agonist muscarine (MUSC), or the selective nicotinic receptor agonists nicotine (NIC) or 1,1-dimethyl-4-phenylpiperazinium (DMPP) also produced membrane depolarizations. The MUSC-induced depolarization was accompanied by decreased conductance, while an increase in conductance appeared to underlie the NIC- and DMPP-induced depolarizations. The muscarinic and nicotinic receptor mediated depolarizations persisted in tetrodotoxin and/or low Ca2+/high Mg2+ containing media, suggesting direct postsynaptic receptor activation. The MUSC-induced depolarization could be reversibly blocked by the selective muscarinic-receptor antagonist, atropine, while the DMPP-induced depolarization could be reversibly suppressed by the selective ganglionic nicotinic-receptor antagonist, mecamylamine. Some neurons exhibited a transient membrane hyperpolarization during the depolarizing response to CCh or MUSC application. This transient inhibition could be reversibly blocked by the gamma-aminobutyric acid (GABA) antagonist, bicuculline, suggesting that the underlying hyperpolarization results indirectly from the endogenous release of GABA acting at GABA receptors. This study confirms the cholinoceptivity of MVN neurons and establishes that individual MVN cells possess muscarinic as well as nicotinic receptors. The data provide support for a prominent role of cholinergic mechanisms in the direct and indirect regulation of the excitability of MVN neurons.

  6. DMPD: Modulation of Toll-interleukin 1 receptor mediated signaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15662540 Modulation of Toll-interleukin 1 receptor mediated signaling. Li X, Qin J....iated signaling. PubmedID 15662540 Title Modulation of Toll-interleukin 1 receptor media... J Mol Med. 2005 Apr;83(4):258-66. Epub 2005 Jan 21. (.png) (.svg) (.html) (.csml) Show Modulation of Toll-interleukin 1 receptor med

  7. Bombesin receptor-mediated imaging and cytotoxicity: review and current status

    OpenAIRE

    Sancho, Veronica; Di Florio, Alessia; Moody, Terry W.; Jensen, Robert T.

    2011-01-01

    The three mammalian bombesin (Bn) receptors (gastrin-releasing peptide [GRP] receptor, neuromedin B [NMB] receptor, BRS-3) are one of the classes of G protein-coupled receptors that are most frequently over-express/ectopically expressed by common, important malignancies. Because of the clinical success of somatostatin receptor-mediated imaging and cytotoxicity with neuroendocrine...

  8. Upregulation of endothelin ETB receptor-mediated vasoconstriction in rat coronary artery after organ culture

    DEFF Research Database (Denmark)

    Eskesen, Karen; Edvinsson, Lars

    2006-01-01

    The aim of this study was to examine if endothelin ET(B) receptor-mediated contraction occurred in isolated segments of rat coronary arteries during organ culture. Presence of contractile endothelin ET(B) receptors was studied by measuring the change in isometric tension in rings of left anterior......(+)-solution was not modified after 1 day in culture medium. The experiments indicate that organ culture of rat coronary arteries upregulate endothelin ET(B) receptor-mediated contraction by inducing synthesis of new protein....... descending coronary arteries isolated from hearts of rats as response to application of the selective endothelin ET(B) receptor agonist, Sarafotoxin 6c and endothelin-1. In segments cultured 1 day in serum free Dulbecco's Modified Eagle's Medium, Sarafotoxin 6c induced a concentration dependent contraction...

  9. Impaired dopamine D1 receptor-mediated vasorelaxation of mesenteric arteries in obese Zucker rats

    OpenAIRE

    Fu, Jinjuan; Han, Yu; Wang, Hongyong; Wang, Zhen; Liu, Yukai; Chen, Xingjian; Cai, Yue; Guan, Weiwei; Yang, Di; Asico, Laureano D.; ZHOU, Lin; Jose, Pedro A; Zeng, Chunyu

    2014-01-01

    Background Obesity plays an important role in the pathogenesis of hypertension. Renal dopamine D1-like receptor-mediated diuresis and natriuresis are impaired in the obese Zucker rat, an obesity-related hypertensive rat model. The role of arterial D1 receptors in the hypertension of obese Zucker rats is not clear. Methods Plasma glucose and insulin concentrations and blood pressure were measured. The vasodilatory response of isolated mesenteric arteries was evaluated using a small vessel myog...

  10. Aryl hydrocarbon receptor mediates benzene-induced hematotoxicity.

    Science.gov (United States)

    Yoon, Byung-Il; Hirabayashi, Yoko; Kawasaki, Yasushi; Kodama, Yukio; Kaneko, Toyozo; Kanno, Jun; Kim, Dae-Yong; Fujii-Kuriyama, Yoshiaki; Inoue, Tohru

    2002-11-01

    regulated by AhR signaling.

  11. Receptor interconversion model of hormone action. 3. Estrogen receptor mediated repression of reporter gene activity in A431 cells.

    Science.gov (United States)

    Nag, A; Park, I; Krust, A; Smith, R G

    1990-03-20

    The chicken estrogen receptor exists in three interconvertible forms, two of which bind estradiol with high affinity and one which lacks the capacity to bind estradiol. Interconversion is regulated by reactions involving ATP/Mg2+. By cotransfecting into A431 cells estrogen receptor cDNA in an expression vector together with the pA2 (-821/-87) tk-CAT vitellogenin construct, we demonstrate that constitutive expression of chloramphenicol acetyltransferase (CAT) activity can be regulated either by selection of ligand or by modifying phosphorylation reactions in the recipient cells. In the presence of estrogen receptors, constitutive expression of CAT activity is inhibited in three situations: (i) in the absence of an estrogenic ligand; (ii) in the presence of an anti-estrogen; and (iii) in the presence of an estrogenic ligand together with 12-O-tetradecanoylphorbol 13-acetate (TPA). Estrogen receptor mediated repression of constitutive CAT activity is not observed with the pA2 (-331/-87) tk-CAT construct, indicating that DNA sequences required for repression are located between -821 and -331 base pairs upstream of the transcription initiation site. PMID:2346742

  12. The Influence of Receptor-Mediated Interactions on Reaction-Diffusion Mechanisms of Cellular Self-organisation

    KAUST Repository

    Klika, Václav

    2011-11-10

    Understanding the mechanisms governing and regulating self-organisation in the developing embryo is a key challenge that has puzzled and fascinated scientists for decades. Since its conception in 1952 the Turing model has been a paradigm for pattern formation, motivating numerous theoretical and experimental studies, though its verification at the molecular level in biological systems has remained elusive. In this work, we consider the influence of receptor-mediated dynamics within the framework of Turing models, showing how non-diffusing species impact the conditions for the emergence of self-organisation. We illustrate our results within the framework of hair follicle pre-patterning, showing how receptor interaction structures can be constrained by the requirement for patterning, without the need for detailed knowledge of the network dynamics. Finally, in the light of our results, we discuss the ability of such systems to pattern outside the classical limits of the Turing model, and the inherent dangers involved in model reduction. © 2011 Society for Mathematical Biology.

  13. M2-like macrophages are responsible for collagen degradation through a mannose receptor-mediated pathway

    DEFF Research Database (Denmark)

    Madsen, Daniel H; Leonard, Daniel; Masedunskas, Andrius;

    2013-01-01

    routed to lysosomes for complete degradation. Collagen uptake was predominantly executed by a quantitatively minor population of M2-like macrophages, whereas more abundant Col1a1-expressing fibroblasts and Cx3cr1-expressing macrophages internalized collagen at lower levels. Genetic ablation...... of the collagen receptors mannose receptor (Mrc1) and urokinase plasminogen activator receptor-associated protein (Endo180 and Mrc2) impaired this intracellular collagen degradation pathway. This study demonstrates the importance of receptor-mediated cellular uptake to collagen turnover in vivo and identifies...

  14. Involvement of cAMP-PKA pathway in group Ⅱ metabotropic glutamate receptors-mediated regulation of respiratory rhythm from neonatal rat brainstem slice%cAMP-PKA通路参与Ⅱ组代谢性谷氨酸受体对新生鼠离体延髓脑片呼吸节律性放电的调节

    Institute of Scientific and Technical Information of China (English)

    郑奇辉; 李国才; 程静; 方芳; 吴中海

    2011-01-01

    本研究旨在探讨cAMP-PKA通路在Ⅱ组代谢性谷氨酸受体对离体延髓脑片呼吸节律性放电的影响中的作用.制作新生大鼠离体延髓脑片标本,主要包含延髓面神经后核内侧区(medial region of the nucleus retrofacialis,mNRF),并完整保留舌下神经根,以改良Kreb's液(modified Kreb's solution,MKS)恒温灌流脑片,用吸附电极记录舌下神经根呼吸节律性放电活动(respiratory rhythmical discharge activity,RRDA).待放电活动稳定后,第1组灌流Ⅱ组代谢性谷氨酸受体特异性拮抗剂(2S)-a-ethylglutamic acid(EGLU)10 min,第2组先给予cAMP-PKA通路激动剂Forskolin灌流10 min,而后MKS洗脱至正常,灌流cAMP-PKA通路抑制剂Rp-cyclic 3',5'-hydrogen phosphorothioate adenosine triethylammonium salt(Rp-cAMPS)10 min,第3组首先给予Rp-cAMPS 10 min,洗脱后联合Rp-cAMPS+EGLU持续灌流10 min,记录各组各时间点RRDA的变化.结果显示,给予Ⅱ组代谢性谷氨酸受体拮抗剂EGLU后,呼吸周期(respiratory cycle,RC)缩短,放电积分幅度(integral amplitude,IA)和吸气时程(inspiratory time,TI)没有变化;Forskolin兴奋呼吸,缩短RC,增加IA,延长TI;Rp-cAMPS则延长RC,降低IA,缩短TI;并且cAMP-PKA通路被阻断之后,EGLU缩短RC的效应也被抑制.这些结果提示在离体延髓水平上,cAMP-PKA通路参与了Ⅱ组代谢性谷氨酸受体对脑片呼吸节律性放电的调节.%The study aims to identify the role of cAMP-PKA pathway in the group II metabotropic glutamate receptors (mGluRs)-mediated regulation of respiratory rhythm from the brainstem slice. Neonatal (aged 0-3 d) Sprague-Dawley rats of either sex were used. The brainstem slice containing the medial region of the nucleus retrofacialis (mNRF) and the hypoglossal nerve rootlets was prepared, and the surgical procedure was performed in the modified Kreb's solution (MK.S) with continuous carbogen (95% O2 and 5% CO2) bubbling, and ended in 3 min. Respiratory rhythmical discharge activity

  15. Role of caveolin-1 in down-regulating extracellular Ca2+-sensing receptor-mediated Ca2+ influx in human umbilical vein endothelial cells%小凹蛋白-1下调人脐静脉内皮细胞外钙敏感受体介导的钙内流的作用机制

    Institute of Scientific and Technical Information of China (English)

    钟华; 龚艳; 吴玲玲; 赵慧; 王静; 孙志萍; 邓峰美; 何芳

    2013-01-01

    AIM: To study the role of caveolin-1 (Cav-1) in down-regulating the extracellular Ca2+-sensing receptor ( CaR)-mediated Ca2+ influx in human umbilical vein endothelial cells (HUVECs) and its mechanisms. METHODS : HUVECs were collected and cultured to the second or third passage. Filipin was used to induce acute caveolae disruption. Methyl-p-cyclodextrin (M[$CD) or shRNA targeting Cav-1 combined with CaR agonist spermine and negative al-losteric modulator Calhex 231 was also used in HUVECs. Intracellular concentration of Ca2+ ([ Ca2+ ] i) was measured by Fura-2/AM loading. The protein expression of Cav-1 and CaR was examined by Western blotting. The interaction and co-localization of Cav-1 and CaR were determined by the method of co-immunoprecipitation (Co-IP). Caveolae-enriched membrane (CEM) fractions were isolated and identified by detergent-free (Na2CO3) sucrose density gradient centrifugation. The protein levels of Cav-1, CaR, flotillin-1,β-coat protein (β-COP) , β-actin and transferrin receptor (TfR) were detec- ted by Western blotting. Noncaveolar fraction I (NCF I) and noncaveolar fraction II (NCF II) in the CEM fractions were separated. RESULTS; Using extracellular buffer with Ca2+ , the increase in [Ca2+ ]i induced by spermine in HUVECs was abolished after inhibition of CaR by its negative allosteric modulator calhex231. Conversely, the effect of spermine on the increased [ Ca 2+], in HUVECs was further augmented after acute caveolae disruption by MβCD. No significant difference of the protein levels of CaR and Cav-1 in HUVECs among treating with different concentrations of MβCD was observed. The results of Co-IP showed that the protein levels of CaR and Cav-1 in every group of HUVECs were not significantly different. Compared with control group, the protein expression of CaR and Cav-1 in CEM was decreased in spermine + Ca2+ group, filipin + spermine + Ca2 + group and MfiCD + spermine + Ca2 + group, and that in NCF I was increased. However, the

  16. Interferon-α/β receptor-mediated selective induction of a gene cluster by CpG oligodeoxynucleotide 2006

    Directory of Open Access Journals (Sweden)

    Wakiguchi Hiroshi

    2003-07-01

    Full Text Available Abstract Background Oligodeoxynucleotides containing unmethylated CpG motifs (CpG ODN are known to exert a strong adjuvant effect on Th1 immune responses. Although several genes have been reported, no comprehensive study of the gene expression profiles in human cells after stimulation with CpG ODN has been reported. Results This study was designed to identify a CpG-inducible gene cluster that potentially predicts for the molecular mechanisms of clinical efficacy of CpG ODN, by determining mRNA expression in human PBMC after stimulation with CpG ODN. PBMCs were obtained from the peripheral blood of healthy volunteers and cultured in the presence or absence of CpG ODN 2006 for up to 24 hours. The mRNA expression profile was evaluated using a high-density oligonucleotide probe array, GeneChip®. Using hierarchical clustering-analysis, out of a total of 10,000 genes we identified a cluster containing 77 genes as having been up-regulated by CpG ODN. This cluster was further divided into two sub-clusters by means of time-kinetics. (1 Inflammatory cytokines such as IL-6 and GM-CSF were up-regulated predominantly 3 to 6 hours after stimulation with CpG ODN, presumably through activation of a transcription factor, NF-κB. (2 Interferon (IFN-inducible anti-viral proteins, including IFIT1, OAS1 and Mx1, and Th1 chemoattractant IP-10, were up-regulated predominantly 6 to 24 hours after stimulation. Blocking with mAb against IFN-α/β receptor strongly inhibited the induction of these IFN-inducible genes by CpG ODN. Conclusion This study provides new information regarding the possible immunomodulatory effects of CpG ODN in vivo via an IFN-α/β receptor-mediated paracrine pathway.

  17. Testin, a novel binding partner of the calcium-sensing receptor, enhances receptor-mediated Rho-kinase signalling

    International Nuclear Information System (INIS)

    Highlights: → A yeast two-hybrid screen revealed testin bound to the calcium-sensing receptor. → The second zinc finger of LIM domain 1 of testin is critical for interaction. → Testin bound to a region of the receptor tail important for cell signalling. → Testin and receptor interaction was confirmed in mammalian (HEK293) cells. → Overexpression of testin enhanced receptor-mediated Rho signalling in HEK293 cells. -- Abstract: The calcium-sensing receptor (CaR) plays an integral role in calcium homeostasis and the regulation of other cellular functions including cell proliferation and cytoskeletal organisation. The multifunctional nature of the CaR is manifested through ligand-dependent stimulation of different signalling pathways that are also regulated by partner binding proteins. Following a yeast two-hybrid library screen using the intracellular tail of the CaR as bait, we identified several novel binding partners including the focal adhesion protein, testin. Testin has not previously been shown to interact with cell surface receptors. The sites of interaction between the CaR and testin were mapped to the membrane proximal region of the receptor tail and the second zinc-finger of LIM domain 1 of testin, the integrity of which was found to be critical for the CaR-testin interaction. The CaR-testin association was confirmed in HEK293 cells by coimmunoprecipitation and confocal microscopy studies. Ectopic expression of testin in HEK293 cells stably expressing the CaR enhanced CaR-stimulated Rho activity but had no effect on CaR-stimulated ERK signalling. These results suggest an interplay between the CaR and testin in the regulation of CaR-mediated Rho signalling with possible effects on the cytoskeleton.

  18. Testin, a novel binding partner of the calcium-sensing receptor, enhances receptor-mediated Rho-kinase signalling

    Energy Technology Data Exchange (ETDEWEB)

    Magno, Aaron L. [Western Australian Institute for Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia 6009 (Australia); Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, Western Australia 6009 (Australia); Ingley, Evan [Western Australian Institute for Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia 6009 (Australia); Brown, Suzanne J. [Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, Western Australia 6009 (Australia); Conigrave, Arthur D. [School of Molecular Bioscience, University of Sydney, New South Wales 2000 (Australia); Ratajczak, Thomas [Western Australian Institute for Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia 6009 (Australia); Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, Western Australia 6009 (Australia); Ward, Bryan K., E-mail: bryanw@cyllene.uwa.edu.au [Western Australian Institute for Medical Research and Centre for Medical Research, University of Western Australia, Nedlands, Western Australia 6009 (Australia); Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, Western Australia 6009 (Australia)

    2011-09-09

    Highlights: {yields} A yeast two-hybrid screen revealed testin bound to the calcium-sensing receptor. {yields} The second zinc finger of LIM domain 1 of testin is critical for interaction. {yields} Testin bound to a region of the receptor tail important for cell signalling. {yields} Testin and receptor interaction was confirmed in mammalian (HEK293) cells. {yields} Overexpression of testin enhanced receptor-mediated Rho signalling in HEK293 cells. -- Abstract: The calcium-sensing receptor (CaR) plays an integral role in calcium homeostasis and the regulation of other cellular functions including cell proliferation and cytoskeletal organisation. The multifunctional nature of the CaR is manifested through ligand-dependent stimulation of different signalling pathways that are also regulated by partner binding proteins. Following a yeast two-hybrid library screen using the intracellular tail of the CaR as bait, we identified several novel binding partners including the focal adhesion protein, testin. Testin has not previously been shown to interact with cell surface receptors. The sites of interaction between the CaR and testin were mapped to the membrane proximal region of the receptor tail and the second zinc-finger of LIM domain 1 of testin, the integrity of which was found to be critical for the CaR-testin interaction. The CaR-testin association was confirmed in HEK293 cells by coimmunoprecipitation and confocal microscopy studies. Ectopic expression of testin in HEK293 cells stably expressing the CaR enhanced CaR-stimulated Rho activity but had no effect on CaR-stimulated ERK signalling. These results suggest an interplay between the CaR and testin in the regulation of CaR-mediated Rho signalling with possible effects on the cytoskeleton.

  19. Muscarinic receptor-mediated calcium changes in a rat model of facial nerve nucleus injury

    Institute of Scientific and Technical Information of China (English)

    Dawei Sun; Huamin Liu; Fugao Zhu; Yanqing Wang; Junfeng Wen; Rui Zhou; Yanjun Wang; Banghua Liu

    2010-01-01

    The muscarinic receptor modulates intracellular free calcium ion levels in the facial nerve nucleus via different channels.In the present study,muscarinic receptor-mediated free calcium ions levels were detected by confocal laser microscopy in the facial nerve nucleus following facial nerve injury in rats.There was no significant difference in muscarinic receptor expression at the affected facial nerve nucleus compared with expression prior to injury,but muscarinic receptor-mediated free calcium ion levels increased in the affected side following facial nerve injury(P < 0.01).At day 30after facial nerve injury,50 μmol/L muscarinic-mediated free calcium ion levels were significantly inhibited at the affected facial nerve nucleus in calcium-free artificial cerebrospinal fluid,and the change range was 82% of artificial cerebrospinal fluid(P < 0.05).These results suggest that increased free calcium ion concentrations are achieved by intracellular calcium ion release,and that the transmembrane flow of calcium ions is also involved in this process.

  20. TRAIL receptor mediates inflammatory cytokine release in an NF-κB-dependent manner

    Institute of Scientific and Technical Information of China (English)

    Wanhu Tang; Weimin Wang; Yaxi Zhang; Shilian Liu; Yanxin Liu; Dexian Zheng

    2009-01-01

    In the present article, we report that DR4 or DR5 overexpression dramatically activates the release of the inflam-matory cytokines IL-8, TNF-α, CCL20, MIP-2 and MIP-1β in an NF-κB-dependent manner in 293T, MDA-MB-231 and HCT-116 cells. We showed that death receptor-mediated signals were extracellular domain-independent, where-as the effect of overexpression of the DR4 intracellular domain was much less potent. The TRADD-TRAF2-NIK-IKKα/β signaling cascade, which plays an essential role in TNF-induced NF-κB activation, was found to be involved in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor-mediated signal transduction. The FADD-caspase signaling pathway, which has been reported to be mostly related to apoptosis, was identified as be-ing essential for DR4 or DR5 overexpression-mediated NF-κB activation and cytokine secretion and crosstalks with the TRADD-TRAF2-NIK-IKKα/β signaling cascade. Furthermore, a DR5 agonistic antibody (AD5-10) triggered the inflammatory cytokine release. These data, together with previous reports, provide strong evidence that TRAIL and TRAIL receptors play an important role in inflammation.

  1. Melanocortin MC(4) receptor-mediated feeding and grooming in rodents.

    Science.gov (United States)

    Mul, Joram D; Spruijt, Berry M; Brakkee, Jan H; Adan, Roger A H

    2013-11-01

    Decades ago it was recognized that the pharmacological profile of melanocortin ligands that stimulated grooming behavior in rats was strikingly similar to that of Xenopus laevis melanophore pigment dispersion. After cloning of the melanocortin MC1 receptor, expressed in melanocytes, and the melanocortin MC4 receptor, expressed mainly in brain, the pharmacological profiles of these receptors appeared to be very similar and it was demonstrated that these receptors mediate melanocortin-induced pigmentation and grooming respectively. Grooming is a low priority behavior that is concerned with care of body surface. Activation of central melanocortin MC4 receptors is also associated with meal termination, and continued postprandial stimulation of melanocortin MC4 receptors may stimulate natural postprandial grooming behavior as part of the behavioral satiety sequence. Indeed, melanocortins fail to suppress food intake or induce grooming behavior in melanocortin MC4 receptor-deficient rats. This review will focus on how melanocortins affect grooming behavior through the melanocortin MC4 receptor, and how melanocortin MC4 receptors mediate feeding behavior. This review also illustrates how melanocortins were the most likely candidates to mediate grooming and feeding based on the natural behaviors they induced.

  2. Amyloid β-protein differentially affects NMDA receptor- and GABAA receptor-mediated currents in rat hippocampal CA1 neurons

    Institute of Scientific and Technical Information of China (English)

    Junfang Zhang; Lei Hou; Xiuping Gao; Fen Guo; Wei Jing; Jinshun Qi; Jiantian Qiao

    2009-01-01

    Although the aggregated amyloid β-protein (Aβ) in senile plaques is one of the key neuropathological features of Alzheimer's disease (AD), soluble forms of Aβ also interfere with synaptic plasticity at the early stage of AD. The suppressive action of acute application of Aβ on hippocampal long-term potentiation (LTP) has been reported widely, whereas the mechanism underlying the effects of Aβ is still mostly unknown. The present study, using the whole-cell patch clamp technique, investigated the effects of Aβ fragments (Aβ25-35 and Aβ31-35) on the LTP induction-related postsynaptic ligand-gated channel currents in isolated hippocampal CA1 neurons. The results showed a rapid but opposite action of both peptides on excitatory and inhibitory receptor currents. Glutamate application-induced currents were suppressed by A β25-35 in a dose-dependent manner, and further N-methyl-I>aspartate (NMDA) receptor-mediated currents were selec-tively inhibited. In contrast, pretreatment with Aβ fragments potentiated γ-aminobutyric acid (GABA)-induced whole-cell currents. As a control, Aβ35-31 the reversed sequence of Aβ35-31 showed no effect on the currents induced by glutamate, NMDA or GABA. These results may partly explain the impaired effects of Aβ on hippocampal LTP, and suggest that the functional down-regulation of N M DA receptors and up-regulation of GABAA receptors may play an important role in remodeling the hippocampal synaptic plasticity in early AD.

  3. pp90rsk1 Regulates Estrogen Receptor-Mediated Transcription through Phosphorylation of Ser-167

    OpenAIRE

    Joel, Peteranne B.; Smith, Jeffrey; Sturgill, Thomas W.; Fisher, Tracey L.; Blenis, John; Lannigan, Deborah A.

    1998-01-01

    The estrogen receptor α (ER), a member of the steroid receptor superfamily, contains an N-terminal hormone-independent transcriptional activation function (AF-1) and a C-terminal hormone-dependent transcriptional activation function (AF-2). Here, we used in-gel kinase assays to determine that pp90rsk1 activated by either epidermal growth factor (EGF) or phorbol myristate acetate specifically phosphorylates Ser-167 within AF-1. In vitro kinase assays demonstrated that pp90rsk1 phosphorylates t...

  4. GPR55 regulates cannabinoid 2 receptor-mediated responses in human neutrophils

    Institute of Scientific and Technical Information of China (English)

    Nariman A B Balenga; Maria Waldhoer; Elma Aflaki; Julia Kargl; Wolfgang Platzer; Ralf Schr(o)der; Stefanie Bl(a)ttermann; Evi Kostenis; Andrew J Brown; Akos Heinemann

    2011-01-01

    The directional migration of neutrophils towards inflammatory mediators,such as chemokines and cannabinoids,occurs via the activation of seven transmembrane G protein coupled receptors (7TM/GPCRs) and is a highly organized process.A crucial role for controlling neutrophil migration has been ascribed to the cannabinoid CB2 receptor (CB2R),but additional modulatory sites distinct from CB2R have recently been suggested to impact CB2R-mediated effector functions in neutrophils.Here,we provide evidence that the recently de-orphanized 7TM/GPCR GPR55potently modulates CB2R-mediated responses.We show that GPR55 is expressed in human blood neutrophils and its activation augments the migratory response towards the CB2R agonist 2-arachidonoylglycerol (2-AG),while inhibiting neutrophil degranulation and reactive oxygen species (ROS) production.Using HEK293 and HL60 cell lines,along with primary neutrophils,we show that GPR55 and CB2R interfere with each other's signaling pathways at the level of small GTPases,such as Rac2 and Cdc42.This ultimately leads to cellular polarization and efficient migration as well as abrogation of degranulation and ROS formation in neutrophils.Therefore,GPR55 limits the tissueinjuring inflammatory responses mediated by CB2R,while it synergizes with CB2R in recruiting neutrophils to sites of inflammation.

  5. Gamma-secretase activity of presenilin 1 regulates acetylcholine muscarinic receptor-mediated signal transduction

    DEFF Research Database (Denmark)

    Popescu, Bogdan O; Cedazo-Minguez, Angel; Benedikz, Eirikur;

    2004-01-01

    Familial Alzheimer's disease (FAD) presenilin 1 (PS1) mutations give enhanced calcium responses upon different stimuli, attenuated capacitative calcium entry, an increased sensitivity of cells to undergo apoptosis, and increased gamma-secretase activity. We previously showed that the FAD mutation...

  6. Transferrin protein nanospheres: a nanoplatform for receptor-mediated cancer cell labeling and gene delivery

    Science.gov (United States)

    McDonald, Michael A.; Spurlin, Tighe A.; Tona, Alessandro; Elliott, John T.; Halter, Michael; Plant, Anne L.

    2010-02-01

    This paper presents preliminary results on the use of transferrin protein nanospheres (TfpNS) for targeting cancer cells in vitro. Protein nanospheres represent an easily prepared and modifiable nanoplatform for receptor-specific targeting, molecular imaging and gene delivery. Rhodamine B isothiocyanate conjugated TfpNS (RBITC-TfpNS) show significantly enhanced uptake in vitro in SK-MEL-28 human malignant melanoma cells known to overexpress transferrin receptors compared to controls. RBITCTfpNS labeling of the cancer cells is due to transferrin receptor-mediated uptake, as demonstrated by competitive inhibition with native transferrin. Initial fluorescence microscopy studies indicate GFP plasmid can be transfected into melanoma cells via GFP plasmid encapsulated by TfpNS.

  7. Exploring the contextual sensitivity of factors that determine cell-to-cell variability in receptor-mediated apoptosis.

    Directory of Open Access Journals (Sweden)

    Suzanne Gaudet

    Full Text Available Stochastic fluctuations in gene expression give rise to cell-to-cell variability in protein levels which can potentially cause variability in cellular phenotype. For TRAIL (TNF-related apoptosis-inducing ligand variability manifests itself as dramatic differences in the time between ligand exposure and the sudden activation of the effector caspases that kill cells. However, the contribution of individual proteins to phenotypic variability has not been explored in detail. In this paper we use feature-based sensitivity analysis as a means to estimate the impact of variation in key apoptosis regulators on variability in the dynamics of cell death. We use Monte Carlo sampling from measured protein concentration distributions in combination with a previously validated ordinary differential equation model of apoptosis to simulate the dynamics of receptor-mediated apoptosis. We find that variation in the concentrations of some proteins matters much more than variation in others and that precisely which proteins matter depends both on the concentrations of other proteins and on whether correlations in protein levels are taken into account. A prediction from simulation that we confirm experimentally is that variability in fate is sensitive to even small increases in the levels of Bcl-2. We also show that sensitivity to Bcl-2 levels is itself sensitive to the levels of interacting proteins. The contextual dependency is implicit in the mathematical formulation of sensitivity, but our data show that it is also important for biologically relevant parameter values. Our work provides a conceptual and practical means to study and understand the impact of cell-to-cell variability in protein expression levels on cell fate using deterministic models and sampling from parameter distributions.

  8. Possible role of death receptor-mediated apoptosis by the E3 ubiquitin ligases Siah2 and POSH

    Directory of Open Access Journals (Sweden)

    Schwarze Steven R

    2011-05-01

    Full Text Available Abstract Background A functioning ubiquitin proteasome system (UPS is essential for a number of diverse cellular processes and maintenance of overall cellular homeostasis. The ability of proteasome inhibitors, such as Velcade, to promote extrinsic apoptotic effects illustrates the importance of the ubiquitin proteasome system in the regulation of death receptor signaling. Here, we set out to define the UPS machinery, particularly the E3 ubiquitin ligases, that repress apoptosis through the extrinsic pathway. A cell-based genome-wide E3 ligase siRNA screen was established to monitor caspase-8 activity following the addition of TRAIL. Results Data from the high-throughput screen revealed that targeting the RING-finger containing E3 ligase Siah2 as well as the signaling platform molecule POSH (SH3RF1 conferred robust caspase-8 activation in response to TRAIL stimulus. Silencing Siah2 or POSH in prostate cancer cells led to increased caspase activity and apoptosis in response to both TRAIL and Fas ligand. The E3 activity of Siah2 was responsible for mediating apoptosis resistance; while POSH protein levels were critical for maintaining viability. Further characterization of Siah2 revealed it to function downstream of early death receptor events in the apoptotic pathway. The observed apoptosis resistance provides one biological explanation for the induction of Siah2 and POSH reported in lung and prostate cancer, respectively. Expanding on an initial yeast-two-hybrid screen we have confirmed a physical interaction between E3 ligases Siah2 and POSH. Utilizing a yeast-two-hybrid mapping approach we have defined the spacer region of POSH, more specifically the RPxAxVxP motif encompassing amino acids 601-607, to be the site of Siah2 binding. Conclusions The data presented here define POSH and Siah2 as important mediators of death receptor mediated apoptosis and suggest targeting the interaction of these two E3 ligases is a promising novel cancer

  9. ZFAT plays critical roles in peripheral T cell homeostasis and its T cell receptor-mediated response

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Keiko [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute of Life Sciences for the Next Generation of Women Scientists, Fukuoka University, Fukuoka (Japan); Fujimoto, Takahiro [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Okamura, Tadashi [Division of Animal Models, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo (Japan); Ogawa, Masahiro [Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Tanaka, Yoko [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Mototani, Yasumasa; Goto, Motohito [Division of Animal Models, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo (Japan); Ota, Takeharu; Matsuzaki, Hiroshi [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Kuroki, Masahide [Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Tsunoda, Toshiyuki [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan); Sasazuki, Takehiko [Institute for Advanced Study, Kyushu University, Fukuoka (Japan); Shirasawa, Senji, E-mail: sshirasa@fukuoka-u.ac.jp [Department of Cell Biology, Faculty of Medicine, Fukuoka University, Fukuoka (Japan); Central Research Institute for Advanced Molecular Medicine, Fukuoka University, Fukuoka (Japan)

    2012-08-17

    Highlights: Black-Right-Pointing-Pointer We generated Cd4-Cre-mediated T cell-specific Zfat-deficient mice. Black-Right-Pointing-Pointer Zfat-deficiency leads to reduction in the number of the peripheral T cells. Black-Right-Pointing-Pointer Impaired T cell receptor-mediated response in Zfat-deficient peripheral T cells. Black-Right-Pointing-Pointer Decreased expression of IL-7R{alpha}, IL-2R{alpha} and IL-2 in Zfat-deficient peripheral T cells. Black-Right-Pointing-Pointer Zfat plays critical roles in peripheral T cell homeostasis. -- Abstract: ZFAT, originally identified as a candidate susceptibility gene for autoimmune thyroid disease, has been reported to be involved in apoptosis, development and primitive hematopoiesis. Zfat is highly expressed in T- and B-cells in the lymphoid tissues, however, its physiological function in the immune system remains totally unknown. Here, we generated the T cell-specific Zfat-deficient mice and demonstrated that Zfat-deficiency leads to a remarkable reduction in the number of the peripheral T cells. Intriguingly, a reduced expression of IL-7R{alpha} and the impaired responsiveness to IL-7 for the survival were observed in the Zfat-deficient T cells. Furthermore, a severe defect in proliferation and increased apoptosis in the Zfat-deficient T cells following T cell receptor (TCR) stimulation was observed with a reduced IL-2R{alpha} expression as well as a reduced IL-2 production. Thus, our findings reveal that Zfat is a critical regulator in peripheral T cell homeostasis and its TCR-mediated response.

  10. Characterization of GABA/sub A/ receptor-mediated 36chloride uptake in rat brain synaptoneurosomes

    International Nuclear Information System (INIS)

    γ-Aminobutyric acid (GABA) receptor-mediated 36chloride (36Cl-) uptake was measured in synaptoneurosomes from rat brain. GABA and GABA agonists stimulated 36Cl- uptake in a concentration-dependent manner with the following order of potency: Muscimol>GABA>piperidine-4-sulfonic acid (P4S)>4,5,6,7-tetrahydroisoxazolo-[5,4-c]pyridin-3-ol (THIP)=3-aminopropanesulfonic acid (3APS)>>taurine. Both P4S and 3APS behaved as partial agonists, while the GABA/sub B/ agonist, baclofen, was ineffective. The response to muscimol was inhibited by bicuculline and picrotoxin in a mixed competitive/non-competitive manner. Other inhibitors of GABA receptor-opened channels or non-neuronal anion channels such as penicillin, picrate, furosemide and disulfonic acid stilbenes also inhibited the response to muscimol. A regional variation in muscimol-stimulated 36Cl- uptake was observed; the largest responses were observed in the cerebral cortex, cerebellum and hippocampus, moderate responses were obtained in the striatum and hypothalamus and the smallest response was observed in the pons-medulla. GABA receptor-mediated 36Cl- uptake was also dependent on the anion present in the media. The muscinol response varied in media containing the following anions: Br->Cl-≥NO3->I-≥SCN->>C3H5OO-≥ClO4->F-, consistent with the relative anion permeability through GABA receptor-gated anion channels and the enhancement of convulsant binding to the GABA receptor-gated Cl- channel. 43 references, 4 figures, 3 tables

  11. Single residues in the surface subunits of oncogenic sheep retrovirus envelopes distinguish receptor-mediated triggering for fusion at low pH and infection

    Energy Technology Data Exchange (ETDEWEB)

    Cote, Marceline [Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada H3A 2B4 (Canada); Zheng, Yi-Min [Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 (United States); Albritton, Lorraine M. [Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163 (United States); Liu, Shan-Lu, E-mail: liushan@missouri.edu [Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada H3A 2B4 (Canada); Department of Molecular Microbiology and Immunology, Bond Life Sciences Center, University of Missouri, Columbia, MO 65211-7310 (United States)

    2011-12-20

    Jaagsiekte sheep retrovirus (JSRV) and enzootic nasal tumor virus (ENTV) are two closely related oncogenic retroviruses that share the same cellular receptor yet exhibit distinct fusogenicity and infectivity. Here, we find that the low fusogenicity of ENTV envelope protein (Env) is not because of receptor binding, but lies in its intrinsic insensitivity to receptor-mediated triggering for fusion at low pH. Distinct from JSRV, shedding of ENTV surface (SU) subunit into culture medium was not enhanced by a soluble form of receptor, Hyal2 (sHyal2), and sHyal2 was unable to effectively inactivate the ENTV pseudovirions. Remarkably, replacing either of the two amino acid residues, N191 or S195, located in the ENTV SU with the corresponding JSRV residues, H191 or G195, markedly increased the Env-mediated membrane fusion activity and infection. Reciprocal amino acid substitutions also partly switched the sensitivities of ENTV and JSRV pseudovirions to sHyal2-mediated SU shedding and inactivation. While N191 is responsible for an extra N-linked glycosylation of ENTV SU relative to that of JSRV, S195 possibly forms a hydrogen bond with a surrounding amino acid residue. Molecular modeling of the pre-fusion structure of JSRV Env predicts that the segment of SU that contains H191 to G195 contacts the fusion peptide and suggests that the H191N and G195S changes seen in ENTV may stabilize its pre-fusion structure against receptor priming and therefore modulate fusion activation by Hyal2. In summary, our study reveals critical determinants in the SU subunits of JSRV and ENTV Env proteins that likely regulate their local structures and thereby differential receptor-mediated fusion activation at low pH, and these findings explain, at least in part, their distinct viral infectivity.

  12. Nicotine impairs cyclooxygenase-2-dependent kinin-receptor-mediated murine airway relaxations

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yuan, E-mail: yuan.xu@ki.se; Cardell, Lars-Olaf

    2014-02-15

    Introduction: Cigarette smoke induces local inflammation and airway hyperreactivity. In asthmatics, it worsens the symptoms and increases the risk for exacerbation. The present study investigates the effects of nicotine on airway relaxations in isolated murine tracheal segments. Methods: Segments were cultured for 24 h in the presence of vehicle, nicotine (10 μM) and/or dexamethasone (1 μM). Airway relaxations were assessed in myographs after pre-contraction with carbachol (1 μM). Kinin receptors, cyclooxygenase (COX) and inflammatory mediator expressions were assessed by real-time PCR and confocal-microscopy-based immunohistochemistry. Results: The organ culture procedure markedly increased bradykinin- (selective B{sub 2} receptor agonist) and des-Arg{sup 9}-bradykinin- (selective B{sub 1} receptor agonist) induced relaxations, and slightly increased relaxation induced by isoprenaline, but not that induced by PGE{sub 2}. The kinin receptor mediated relaxations were epithelium-, COX-2- and EP2-receptor-dependent and accompanied by drastically enhanced mRNA levels of kinin receptors, as well as inflammatory mediators MCP-1 and iNOS. Increase in COX-2 and mPGES-1 was verified both at mRNA and protein levels. Nicotine selectively suppressed the organ-culture-enhanced relaxations induced by des-Arg{sup 9}-bradykinin and bradykinin, at the same time reducing mPGES-1 mRNA and protein expressions. α7-nicotinic acetylcholine receptor inhibitors α-bungarotoxin and MG624 both blocked the nicotine effects on kinin B{sub 2} receptors, but not those on B{sub 1}. Dexamethasone completely abolished kinin-induced relaxations. Conclusion: It is tempting to conclude that a local inflammatory process per se could have a bronchoprotective component by increasing COX-2 mediated airway relaxations and that nicotine could impede this safety mechanism. Dexamethasone further reduced airway inflammation together with relaxations. This might contribute to the steroid resistance seen in

  13. Kainate receptors mediate signaling in both transient and sustained OFF bipolar cell pathways in mouse retina.

    Science.gov (United States)

    Borghuis, Bart G; Looger, Loren L; Tomita, Susumu; Demb, Jonathan B

    2014-04-30

    A fundamental question in sensory neuroscience is how parallel processing is implemented at the level of molecular and circuit mechanisms. In the retina, it has been proposed that distinct OFF cone bipolar cell types generate fast/transient and slow/sustained pathways by the differential expression of AMPA- and kainate-type glutamate receptors, respectively. However, the functional significance of these receptors in the intact circuit during light stimulation remains unclear. Here, we measured glutamate release from mouse bipolar cells by two-photon imaging of a glutamate sensor (iGluSnFR) expressed on postsynaptic amacrine and ganglion cell dendrites. In both transient and sustained OFF layers, cone-driven glutamate release from bipolar cells was blocked by antagonists to kainate receptors but not AMPA receptors. Electrophysiological recordings from bipolar and ganglion cells confirmed the essential role of kainate receptors for signaling in both transient and sustained OFF pathways. Kainate receptors mediated responses to contrast modulation up to 20 Hz. Light-evoked responses in all mouse OFF bipolar pathways depend on kainate, not AMPA, receptors.

  14. Killing of intracellular Mycobacterium tuberculosis by receptor-mediated drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, S.; Basu, S.K. (Institute of Microbial Technology, Chandigarh (India))

    1991-01-01

    p-Aminosalicylic acid (PAS) conjugated to maleylated bovine serum albumin (MBSA) was taken up efficiently through high-affinity MBSA-binding sites on macrophages. Binding of the radiolabeled conjugate to cultured mouse peritoneal macrophages at 4 degrees C was competed for by MBSA but not by PAS. At 37 degrees C, the radiolabeled conjugate was rapidly degraded by the macrophages, leading to release of acid-soluble degradation products in the medium. The drug conjugate was nearly 100 times as effective as free PAS in killing the intracellular mycobacteria in mouse peritoneal macrophages infected in culture with Mycobacterium tuberculosis. The killing of intracellular mycobacteria mediated by the drug conjugate was effectively prevented by simultaneous addition of excess MBSA (100 micrograms/ml) or chloroquine (3 microM) to the medium, whereas these agents did not affect the microbicidal action of free PAS. These results suggest that (i) uptake of the PAS-MBSA conjugate was mediated by cell surface receptors on macrophages which recognize MBSA and (ii) lysosomal hydrolysis of the internalized conjugate resulted in intracellular release of a pharmacologically active form of the drug, which led to selective killing of the M. tuberculosis harbored by mouse macrophages infected in culture. This receptor-mediated modality of delivering drugs to macrophages could contribute to greater therapeutic efficacy and minimization of toxic side effects in the management of tuberculosis and other intracellular mycobacterial infections.

  15. Cryptococcus neoformans is internalized by receptor-mediated or 'triggered' phagocytosis, dependent on actin recruitment.

    Directory of Open Access Journals (Sweden)

    Caroline Rezende Guerra

    Full Text Available Cryptococcosis by the encapsulated yeast Cryptococcus neoformans affects mostly immunocompromised individuals and is a frequent neurological complication in AIDS patients. Recent studies support the idea that intracellular survival of Cryptococcus yeast cells is important for the pathogenesis of cryptococcosis. However, the initial steps of Cryptococcus internalization by host cells remain poorly understood. Here, we investigate the mechanism of Cryptococcus neoformans phagocytosis by peritoneal macrophages using confocal and electron microscopy techniques, as well as flow cytometry quantification, evaluating the importance of fungal capsule production and of host cell cytoskeletal elements for fungal phagocytosis. Electron microscopy analyses revealed that capsular and acapsular strains of C. neoformans are internalized by macrophages via both 'zipper' (receptor-mediated and 'trigger' (membrane ruffle-dependent phagocytosis mechanisms. Actin filaments surrounded phagosomes of capsular and acapsular yeasts, and the actin depolymerizing drugs cytochalasin D and latrunculin B inhibited yeast internalization and actin recruitment to the phagosome area. In contrast, nocodazole and paclitaxel, inhibitors of microtubule dynamics decreased internalization but did not prevent actin recruitment to the site of phagocytosis. Our results show that different uptake mechanisms, dependent on both actin and tubulin dynamics occur during yeast internalization by macrophages, and that capsule production does not affect the mode of Cryptococcus uptake by host cells.

  16. Progesterone stimulates respiration through a central nervous system steroid receptor-mediated mechanism in cat.

    Science.gov (United States)

    Bayliss, D A; Millhorn, D E; Gallman, E A; Cidlowski, J A

    1987-11-01

    We have examined the effect on respiration of the steroid hormone progesterone, administered either intravenously or directly into the medulla oblongata in anesthetized and paralyzed male and female cats. The carotid sinus and vagus nerves were cut, and end-tidal PCO2 and temperature were kept constant with servo-controllers. Phrenic nerve activity was used to quantitate central respiratory activity. Repeated doses of progesterone (from 0.1 to 2.0 micrograms/kg, cumulative) caused a sustained (greater than 45 min) facilitation of phrenic nerve activity in female and male cats; however, the response was much more variable in females. Progesterone injected into the region of nucleus tractus solitarii, a respiratory-related area in the medulla oblongata, also caused a prolonged stimulation of respiration. Progesterone administration at high concentration by both routes also caused a substantial hypotension. Identical i.v. doses of other classes of steroid hormones (17 beta-estradiol, testosterone, and cortisol) did not elicit the same respiratory effect. Pretreatment with RU 486, a progesterone-receptor antagonist, blocked the facilitatory effect of progesterone. We conclude that progesterone acts centrally through a steroid receptor-mediated mechanism to facilitate respiration. PMID:3478727

  17. Receptor-mediated endocytosis of lysozyme in renal proximal tubules of the frog Rana temporaria

    Directory of Open Access Journals (Sweden)

    E.V. Seliverstova

    2015-04-01

    Full Text Available The mechanism of protein reabsorption in the kidney of lower vertebrates remains insufficiently investigated in spite of raising interest to the amphibian and fish kidneys as a useful model for physiological and pathophysiological examinations. In the present study, we examined the renal tubular uptake and the internalization rote of lysozyme after its intravenous injection in the wintering frog Rana temporaria using immunohisto- and immunocytochemistry and specific markers for some endocytic compartments. The distinct expression of megalin and cubilin in the proximal tubule cells of lysozyme-injected frogs was revealed whereas kidney tissue of control animals showed no positive immunoreactivity. Lysozyme was detected in the apical endocytic compartment of the tubular cells and colocalized with clathrin 10 min after injection. After 20 min, lysozyme was located in the subapical compartment negative to clathrin (endosomes, and intracellular trafficking of lysozyme was coincided with the distribution of megalin and cubilin. However, internalized protein was retained in the endosomes and did not reach lysosomes within 30 min after treatment that may indicate the inhibition of intracellular trafficking in hibernating frogs. For the first time, we provided the evidence that lysozyme is filtered through the glomeruli and absorbed by receptor-mediated clathrin-dependent endocytosis in the frog proximal tubule cells. Thus, the protein uptake in the amphibian mesonephros is mediated by megalin and cubilin that confirms a critical role of endocytic receptors in the renal reabsorption of proteins in amphibians as in mammals.

  18. Receptor-Mediated and Fluid-Phase Transcytosis of Horseradish Peroxidase across Rat Hepatocytes

    Directory of Open Access Journals (Sweden)

    Isabella Ellinger

    2010-01-01

    Full Text Available Horseradish peroxidase (HRP is often used as a fluid-phase marker to characterize endocytic and transcytotic processes. Likewise, it has been applied to investigate the mechanisms of biliary secretion of fluid in rat liver hepatocytes. However, HRP contains mannose residues and thus binds to mannose receptors (MRs on liver cells, including hepatocytes. To study the role of MR-mediated endocytosis of HRP transport in hepatocytes, we determined the influence of the oligosaccharid mannan on HRP biliary secretion in the isolated perfused rat liver. A 1-minute pulse of HRP was applied followed by marker-free perfusion. HRP appeared in bile with biphasic kinetics: a first peak at 7 minutes and a second peak at 15 minutes after labeling. Perfusion with 0.8 mg/mL HRP in the presence of a twofold excess of mannan reduced the first peak by 41% without effect on the second one. Together with recently published data on MR expression in rat hepatocytes this demonstrates two different mechanisms for HRP transcytosis: a rapid, receptor-mediated transport and a slower fluid-phase transport.

  19. Sucrose-induced analgesia in mice: Role of nitric oxide and opioid receptor-mediated system

    Directory of Open Access Journals (Sweden)

    Abtin Shahlaee

    2013-01-01

    Full Text Available Background: The mechanism of action of sweet substance-induced analgesia is thought to involve activation of the endogenous opioid system. The nitric oxide (NO pathway has a pivotal role in pain modulation of analgesic compounds such as opioids. Objectives: We investigated the role of NO and the opioid receptor-mediated system in the analgesic effect of sucrose ingestion in mice. Materials and Methods: We evaluated the effect of intraperitoneal administration of 10 mg/kg of NO synthase inhibitor, N-nitro-L-arginine methyl ester (L-NAME and 20 mg/kg of opioid receptor antagonist, naltrexone on the tail flick response in sucrose ingesting mice. Results: Sucrose ingestion for 12 days induced a statistically significant increase in the latency of tail flick response which was unmodified by L-NAME, but partially inhibited by naltrexone administration. Conclusions: Sucrose-induced nociception may be explained by facilitating the release of endogenous opioid peptides. Contrary to some previously studied pain models, the NO/cyclic guanosine monophosphate (cGMP pathway had no role in thermal hyperalgesia in our study. We recommend further studies on the involvement of NO in other animals and pain models.

  20. Luteinizing hormone-releasing hormone receptor-mediated delivery of mitoxantrone using LHRH analogs modified with PEGylated liposomes

    OpenAIRE

    Sun, Hongfan

    2010-01-01

    Yingna He, Linhua Zhang, Cunxian SongKey Laboratory of Biomedical Material of Tianjin, Institute of Biomedical Engineering, Peking Union Medical College and Chinese Academy of Medical Sciences, Tianjin, ChinaAbstract: A sterically stabilized, mitoxantrone-loaded liposome, tailored to target luteinizing hormone-releasing hormone (LHRH) receptor overexpressing cells, was developed to promote the efficiency of intracellular delivery of mitoxantrone through receptor-mediated endocytosis. Liposome...

  1. Pharmacological and biochemical characterization of the D-1 dopamine receptor mediating acetylcholine release in rabbit retina

    Energy Technology Data Exchange (ETDEWEB)

    Hensler, J.G.; Cotterell, D.J.; Dubocovich, M.L.

    1987-12-01

    Superfusion with dopamine (0.1 microM-10 mM) evokes calcium-dependent (/sup 3/H)acetylcholine release from rabbit retina labeled in vitro with (/sup 3/H)choline. This effect is antagonized by the D-1 dopamine receptor antagonist SCH 23390. Activation or blockade of D-2 dopamine, alpha-2 or beta receptors did not stimulate or attenuate the release of (/sup 3/H)acetylcholine from rabbit retina. Dopamine receptor agonists evoke the release of (/sup 3/H)acetylcholine with the following order of potency: apomorphine less than or equal to SKF(R)82526 < SKF 85174 < SKF(R)38393 less than or equal to pergolide less than or equal to dopamine (EC50 = 4.5 microM) < SKF(S)82526 less than or equal to SKF(S)38393. Dopamine receptor antagonists inhibited the dopamine-evoked release of (/sup 3/H)acetylcholine: SCH 23390 (IC50 = 1 nM) < (+)-butaclamol less than or equal to cis-flupenthixol < fluphenazine < perphenazine < trans-flupenthixol < R-sulpiride. The potencies of dopamine receptor agonists and antagonists at the dopamine receptor mediating (/sup 3/H)acetylcholine release is characteristic of the D-1 dopamine receptor. These potencies were correlated with the potencies of dopamine receptor agonists and antagonists at the D-1 dopamine receptor in rabbit retina as labeled by (/sup 3/H)SCH 23390, or as determined by adenylate cyclase activity. (/sup 3/H)SCH 23390 binding in rabbit retinal membranes was stable, saturable and reversible. Scatchard analysis of (/sup 3/H)SCH 23390 saturation data revealed a single high affinity binding site (Kd = 0.175 +/- 0.002 nM) with a maximum binding of 482 +/- 12 fmol/mg of protein. The potencies of dopamine receptor agonists to stimulate (/sup 3/H)acetylcholine release were correlated with their potencies to stimulate adenylate cyclase (r = 0.784, P less than .05, n = 7) and with their affinities at (/sup 3/H)SCH 23390 binding sites (r = 0.755, P < .05, n = 8).

  2. Astrocytes protect neurons against methylmercury via ATP/P2Y(1 receptor-mediated pathways in astrocytes.

    Directory of Open Access Journals (Sweden)

    Yusuke Noguchi

    Full Text Available 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.

  3. Development and validation of in vitro bioassays for thyroid hormone receptor mediated endocrine disruption

    NARCIS (Netherlands)

    Freitas, de J.

    2012-01-01

    Thyroid hormones regulate crucial processes in vertebrates such as reproduction, development and energy metabolism. Endocrine disruption via the thyroid hormone system is gaining more attention both from scientists and regulators, because of the increasing incidence of hormone-related cancers and de

  4. Multi-functionalized hyaluronic acid nanogels crosslinked with carbon dots as dual receptor-mediated targeting tumor theranostics.

    Science.gov (United States)

    Jia, Xu; Han, Yu; Pei, Mingliang; Zhao, Xubo; Tian, Kun; Zhou, Tingting; Liu, Peng

    2016-11-01

    Hyaluronic acid (HA)-based theranostic nanogels were designed for the tumor diagnosis and chemotherapy, by crosslinking the folate-terminated poly(ethylene glycol) modified hyaluronic acid (FA-PEG-HA) with carbon dots (CDs) for the first time. Due to the extraordinary fluorescence property of the integrated CDs, the theranostic nanogels could be used for the real-time and noninvasive location tracking to cancer cells. HA could load Doxorubicin (DOX) via electrostatic interaction with a drug-loading capacity (DLC) of 32.5%. The nanogels possessed an ideal release of DOX in the weak acid environment, while it was restrained in the neutral media, demonstrating the pH-responsive controlled release behavior. The cytotoxicity and cellular uptake results clearly illustrated that most DOX was released and accumulated in the cell nuclei and killed the cancer cells efficaciously, due to their dual receptor-mediated targeting characteristics. PMID:27516286

  5. Genetically designed biomolecular capping system for mesoporous silica nanoparticles enables receptor-mediated cell uptake and controlled drug release

    CERN Document Server

    Datz, Stefan; Gattner, Michael; Weiss, Veronika; Brunner, Korbinian; Bretzler, Johanna; von Schirnding, Constantin; Spada, Fabio; Engelke, Hanna; Vrabel, Milan; Bräuchle, Christoph; Carell, Thomas; Bein, Thomas

    2015-01-01

    Effective and controlled drug delivery systems with on-demand release and targeting abilities have received enormous attention for biomedical applications. Here, we describe a novel enzyme-based cap system for mesoporous silica nanoparticles (MSNs) that is directly combined with a targeting ligand via bio-orthogonal click chemistry. The capping system is based on the pH-responsive binding of an aryl-sulfonamide-functionalized MSN and the enzyme carbonic anhydrase (CA). An unnatural amino acid (UAA) containing a norbornene moiety was genetically incorporated into CA. This UAA allowed for the site-specific bio-orthogonal attachment of even very sensitive targeting ligands such as folic acid and anandamide. This leads to specific receptor-mediated cell and stem cell uptake. We demonstrate the successful delivery and release of the chemotherapeutic agent Actinomycin D to KB cells. This novel nanocarrier concept provides a promising platform for the development of precisely controllable and highly modular theranos...

  6. ERK/Egr-1 signaling pathway is involved in CysLT2 receptor-mediated IL-8 production in HEK293 cells.

    Science.gov (United States)

    Lin, Kana; Fang, Sanhua; Cai, Beilei; Huang, Xueqin; Zhang, Xiayan; Lu, Yunbi; Zhang, Weiping; Wei, Erqing

    2014-07-01

    The CysLT2 receptor is involved in myocardial ischemia/reperfusion injury, differentiation of colorectal cancers, bleomycin-induced pulmonary inflammation and fibrosis. However, the signal transduction of cysteinyl leukotriene receptor 2 (CysLT2) in inflammatory responses remains to be clarified. In HEK293 cells stably expressing hCysLT1, hCysLT2 and rGPR17, we determined the signaling pathways for interleukin-8 (IL-8) production after CysLT2 receptor activation. HEK293 cells were stably transfected with the recombinant plasmids of pcDNA3.1(+)-hCysLT1, pcDNA3.1(+)-hCysLT2 and pcDNA3.1-rGPR17. Leukotriene C4 (LTC4) and LTD4 were used as the agonists to induce IL-8 production and the related changes in signal molecules. We found that LTC4 and LTD4 significantly induced IL-8 promoter activation in the HEK293 cells stably expressing hCysLT2, but not in those expressing hCysLT1 and rGPR17. In hCysLT2-HEK293 cells, LTC4 induced elevation of intracellular calcium, ERK1/2 phosphorylation and Egr-1 expression, and stimulated IL-8 expression and release. These responses were blocked by the selective CysLT2 receptor antagonist HAMI3379. The ERK1/2 inhibitor U0126 inhibited Egr-1 and IL-8 expression as well as IL-8 release, but the JNK and p38 inhibitors did not have the inhibitory effects. Down-regulation of Egr-1 by RNA interference with its siRNA inhibited the LTC4-induced IL-8 expression and release. In conclusion, these findings indicate the ERK-Egr-1 pathway of CysLT2 receptors mediates IL-8 production induced by the pro-inflammatory mediators LTC4 and LTD4.

  7. Brain tumor-targeted therapy by systemic delivery of siRNA with Transferrin receptor-mediated core-shell nanoparticles.

    Science.gov (United States)

    Wei, Lin; Guo, Xi-Ying; Yang, Ting; Yu, Min-Zhi; Chen, Da-Wei; Wang, Jian-Cheng

    2016-08-20

    Treatment of brain tumor remains a great challenge worldwide. Development of a stable, safe, and effective siRNA delivery system which is able to cross the impermeable blood-brain barrier (BBB) and target glioma cells is necessary. This study aims to investigate the therapeutic effects of intravenous administration of T7 peptide modified core-shell nanoparticles (named T7-LPC/siRNA NPs) on brain tumors. Layer-by-layer assembling of protamine/chondroitin sulfate/siRNA/cationic liposomes followed by T7 peptide modification has been carried out in order to obtain a targeted siRNA delivery system. In vitro cellular uptake experiments demonstrated a higher intracellular fluorescence intensity of siRNA in brain microvascular endothelial cells (BMVECs) and U87 glioma cells when treated with T7-LPC/siRNA NPs compared with PEG-LPC/siRNA NPs. In the co-culture model of BMVECs and U87 cells, a significant down-regulation of EGFR protein expression occurred in the U87 glioma cells after treatment with the T7-LPC/siEGFR NPs. Moreover, the T7-LPC/siRNA NPs had an advantage in penetrating into a deep region of the tumor spheroid compared with PEG-LPC/siRNA NPs. In vivo imaging revealed that T7-LPC/siRNA NPs accumulated more specifically in brain tumor tissues than the non-targeted NPs. Also, in vivo tumor therapy experiments demonstrated that the longest survival period along with the greatest downregulation of EGFR expression in tumor tissues was observed in mice with an intracranial U87 glioma treated with T7-LPC/siEGFR NPs compared with mice receiving other formulations. Therefore, we believe that these transferrin receptor-mediated core-shell nanoparticles are an important potential siRNA delivery system for brain tumor-targeted therapy.

  8. Increased desensitization of dopamine D₂ receptor-mediated response in the ventral tegmental area in the absence of adenosine A(2A) receptors.

    Science.gov (United States)

    Al-Hasani, R; Foster, J D; Metaxas, A; Ledent, C; Hourani, S M O; Kitchen, I; Chen, Y

    2011-09-01

    G-protein coupled receptors interact to provide additional regulatory mechanisms for neurotransmitter signaling. Adenosine A(2A) receptors are expressed at a high density in striatal neurons, where they closely interact with dopamine D₂ receptors and modulate effects of dopamine and responses to psychostimulants. A(2A) receptors are expressed at much lower densities in other forebrain neurons but play a more prominent yet opposing role to striatal receptors in response to psychostimulants in mice. It is, therefore, possible that A(2A) receptors expressed at low levels elsewhere in the brain may also regulate neurotransmitter systems and modulate neuronal functions. Dopamine D₂ receptors play an important role in autoinhibition of neuronal firing in dopamine neurons of the ventral tegmental area (VTA) and dopamine release in other brain areas. Here, we examined the effect of A(2A) receptor deletion on D₂ receptor-mediated inhibition of neuronal firing in dopamine neurons in the VTA. Spontaneous activity of dopamine neurons was recorded in midbrain slices, and concentration-dependent effects of the dopamine D₂ receptor agonist, quinpirole, was compared between wild-type and A(2A) knockout mice. The potency of quinpirole applied in single concentrations and the expression of D₂ receptors were not altered in the VTA of the knockout mice. However, quinpirole applied in stepwise escalating concentrations caused significantly reduced maximal inhibition in A(2A) knockout mice, indicating an enhanced agonist-induced desensitization of D₂ receptors in the absence of A(2A) receptors. The A(2A) receptor agonist, CGS21680, did not exert any effect on dopamine neuron firing or response to quinpirole, revealing a novel non-pharmacological interaction between adenosine A(2A) receptors and dopaminergic neurotransmission in midbrain dopamine neurons. Altered D₂ receptor desensitization may result in changes in dopamine neuron firing rate and pattern and dopamine

  9. Loss of progesterone receptor-mediated actions induce preterm cellular and structural remodeling of the cervix and premature birth.

    Directory of Open Access Journals (Sweden)

    Steven M Yellon

    Full Text Available A decline in serum progesterone or antagonism of progesterone receptor function results in preterm labor and birth. Whether characteristics of premature remodeling of the cervix after antiprogestins or ovariectomy are similar to that at term was the focus of the present study. Groups of pregnant rats were treated with vehicle, a progesterone receptor antagonist (onapristone or mifepristone, or ovariectomized on day 17 postbreeding. As expected, controls given vehicle delivered at term while rats delivered preterm after progesterone receptor antagonist treatment or ovariectomy. Similar to the cervix before term, the preterm cervix of progesterone receptor antagonist-treated rats was characterized by reduced cell nuclei density, decreased collagen content and structure, as well as a greater presence of macrophages per unit area. Thus, loss of nuclear progesterone receptor-mediated actions promoted structural remodeling of the cervix, increased census of resident macrophages, and preterm birth much like that found in the cervix at term. In contrast to the progesterone receptor antagonist-induced advance in characteristics associated with remodeling, ovariectomy-induced loss of systemic progesterone did not affect hypertrophy, extracellular collagen, or macrophage numbers in the cervix. Thus, the structure and macrophage census in the cervix appear sufficient for premature ripening and birth to occur well before term. With progesterone receptors predominantly localized on cells other than macrophages, the findings suggest that interactions between cells may facilitate the loss of progesterone receptor-mediated actions as part of a final common mechanism that remodels the cervix in certain etiologies of preterm and with parturition at term.

  10. Characterization of GABA/sub A/ receptor-mediated /sup 36/chloride uptake in rat brain synaptoneurosomes

    Energy Technology Data Exchange (ETDEWEB)

    Luu, M.D.; Morrow, A.L.; Paul, S.M.; Schwartz, R.D.

    1987-09-07

    ..gamma..-Aminobutyric acid (GABA) receptor-mediated /sup 36/chloride (/sup 36/Cl/sup -/) uptake was measured in synaptoneurosomes from rat brain. GABA and GABA agonists stimulated /sup 36/Cl/sup -/ uptake in a concentration-dependent manner with the following order of potency: Muscimol>GABA>piperidine-4-sulfonic acid (P4S)>4,5,6,7-tetrahydroisoxazolo-(5,4-c)pyridin-3-ol (THIP)=3-aminopropanesulfonic acid (3APS)>>taurine. Both P4S and 3APS behaved as partial agonists, while the GABA/sub B/ agonist, baclofen, was ineffective. The response to muscimol was inhibited by bicuculline and picrotoxin in a mixed competitive/non-competitive manner. Other inhibitors of GABA receptor-opened channels or non-neuronal anion channels such as penicillin, picrate, furosemide and disulfonic acid stilbenes also inhibited the response to muscimol. A regional variation in muscimol-stimulated /sup 36/Cl/sup -/ uptake was observed; the largest responses were observed in the cerebral cortex, cerebellum and hippocampus, moderate responses were obtained in the striatum and hypothalamus and the smallest response was observed in the pons-medulla. GABA receptor-mediated /sup 36/Cl/sup -/ uptake was also dependent on the anion present in the media. The muscinol response varied in media containing the following anions: Br/sup -/>Cl/sup -/greater than or equal toNO/sub 3//sup -/>I/sup -/greater than or equal toSCN/sup -/>>C/sub 3/H/sub 5/OO/sup -/greater than or equal toClO/sub 4//sup -/>F/sup -/, consistent with the relative anion permeability through GABA receptor-gated anion channels and the enhancement of convulsant binding to the GABA receptor-gated Cl/sup -/ channel. 43 references, 4 figures, 3 tables.

  11. Prostaglandin E2 potentiation of P2X3 receptor mediated currents in dorsal root ganglion neurons

    Directory of Open Access Journals (Sweden)

    Huang Li-Yen

    2007-08-01

    Full Text Available Abstract Prostaglandin E2 (PGE2 is a well-known inflammatory mediator that enhances the excitability of DRG neurons. Homomeric P2X3 and heteromeric P2X2/3 receptors are abundantly expressed in dorsal root ganglia (DRG neurons and participate in the transmission of nociceptive signals. The interaction between PGE2 and P2X3 receptors has not been well delineated. We studied the actions of PGE2 on ATP-activated currents in dissociated DRG neurons under voltage-clamp conditions. PGE2 had no effects on P2X2/3 receptor-mediated responses, but significantly potentiated fast-inactivating ATP currents mediated by homomeric P2X3 receptors. PGE2 exerted its action by activating EP3 receptors. To study the mechanism underlying the action of PGE2, we found that the adenylyl cyclase activator, forskolin and the membrane-permeable cAMP analogue, 8-Br-cAMP increased ATP currents, mimicking the effect of PGE2. In addition, forskolin occluded the enhancement produced by PGE2. The protein kinase A (PKA inhibitors, H89 and PKA-I blocked the PGE2 effect. In contrast, the PKC inhibitor, bisindolymaleimide (Bis did not change the potentiating action of PGE2. We further showed that PGE2 enhanced α,β-meATP-induced allodynia and hyperalgesia and the enhancement was blocked by H89. These observations suggest that PGE2 binds to EP3 receptors, resulting in the activation of cAMP/PKA signaling pathway and leading to an enhancement of P2X3 homomeric receptor-mediated ATP responses in DRG neurons.

  12. Intracellular Ca2+ release through ryanodine receptors contributes to AMPA receptor-mediated mitochondrial dysfunction and ER stress in oligodendrocytes

    Science.gov (United States)

    Ruiz, A; Matute, C; Alberdi, E

    2010-01-01

    Overactivation of ionotropic glutamate receptors in oligodendrocytes induces cytosolic Ca2+ overload and excitotoxic death, a process that contributes to demyelination and multiple sclerosis. Excitotoxic insults cause well-characterized mitochondrial alterations and endoplasmic reticulum (ER) dysfunction, which is not fully understood. In this study, we analyzed the contribution of ER-Ca2+ release through ryanodine receptors (RyRs) and inositol triphosphate receptors (IP3Rs) to excitotoxicity in oligodendrocytes in vitro. First, we observed that oligodendrocytes express all previously characterized RyRs and IP3Rs. Blockade of Ca2+-induced Ca2+ release by TMB-8 following α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptor-mediated insults attenuated both oligodendrocyte death and cytosolic Ca2+ overload. In turn, RyR inhibition by ryanodine reduced as well the Ca2+ overload whereas IP3R inhibition was ineffective. Furthermore, AMPA-triggered mitochondrial membrane depolarization, oxidative stress and activation of caspase-3, which in all instances was diminished by RyR inhibition. In addition, we observed that AMPA induced an ER stress response as revealed by α subunit of the eukaryotic initiation factor 2α phosphorylation, overexpression of GRP chaperones and RyR-dependent cleavage of caspase-12. Finally, attenuating ER stress with salubrinal protected oligodendrocytes from AMPA excitotoxicity. Together, these results show that Ca2+ release through RyRs contributes to cytosolic Ca2+ overload, mitochondrial dysfunction, ER stress and cell death following AMPA receptor-mediated excitotoxicity in oligodendrocytes. PMID:21364659

  13. Glucocorticoid receptor-mediated induction of glutamine synthetase in skeletal muscle cells in vitro

    Science.gov (United States)

    Max, Stephen R.; Thomas, John W.; Banner, Carl; Vitkovic, Ljubisa; Konagaya, Masaaki

    1987-01-01

    The regulation by glucocorticoids of glutamine synthetase in L6 muscle cells in culture is studied. Glutamine synthetase activity was strikingly enhanced by dexamethasone. The dexamethasone-mediated induction of glutamine synthetase activity was blocked by RU38486, a glucocorticoid antagonist, indicating the involvement of intracellular glucocorticoid receptors in the induction process. RU38486 alone was without effect. Northern blot analysis revealed that dexamethasone-mediated enhancement of glutamine synthetase activity involves increased levels of glutamine synthetase mRNA. Glucocorticoids regulate the expression of glutamine synthetase mRNA in cultured muscle cells via interaction with intracellular receptors. Such regulation may be relevant to control of glutamine production by muscle.

  14. A Boolean Network Model of Nuclear Receptor Mediated Cell Cycle Progression

    Science.gov (United States)

    Nuclear receptors (NRs) are ligand-activated transcription factors that regulate a broad range of cellular processes. Hormones, lipids and xenobiotics have been shown to activate NRs with a range of consequences on development, metabolism, oxidative stress, apoptosis, and prolif...

  15. A Boolean Network Model of Nuclear Receptor Mediated Cell Cycle Progression (S)

    Science.gov (United States)

    Nuclear receptors (NRs) are ligand-activated transcription factors that regulate a broad range of cellular processes. Hormones, lipids and xenobiotics have been shown to activate NRs with a range of consequences on development, metabolism, oxidative stress, apoptosis, and prolif...

  16. Plasma membrane Ca2+ pumping plays a prominent role in adenosine A(1) receptor mediated changes in [Ca2+](i) in DDT1 MF-2 cells

    NARCIS (Netherlands)

    Sipma, H; Fredholm, BB; DenHertog, A; Nelemans, A

    1996-01-01

    Adenosine A(1) receptor mediated formation of inositol 1,4,5-trisphosphate (Ins(1,4,5)P-3) and accumulation of cytoplasmic Ca2+ ([Ca2+](i)) were investigated in DDT1 MF-2 smooth muscle cells. A strong reduction of the adenosine and N-6-cyclopentyladenosine (CPA) induced rise in [Ca2+](i) was observe

  17. Glucocorticoid receptor, but not mineralocorticoid receptor, mediates cortisol regulation of epidermal ionocyte development and ion transport in zebrafish (danio rerio.

    Directory of Open Access Journals (Sweden)

    Shelly Abad Cruz

    Full Text Available Cortisol is the major endogenous glucocorticoid (GC both in human and fish, mediated by corticosteroid receptors. Due to the absence of aldosterone production in teleost fish, cortisol is also traditionally accepted to function as mineralocorticoid (MC; but whether it acts through the glucocorticoid receptor (GR or the mineralocorticoid receptor (MR remains a subject of debate. Here, we used loss-of-function and rescue assays to determine whether cortisol affects zebrafish epidermal ionocyte development and function via the GR and/or the MR. GR knockdown morphants displayed a significant decrease in the major ionocytes, namely Na(+-K(+-ATPase-rich cells (NaRCs and H(+-ATPase-rich cells (HRCs, as well as other cells, including epidermal stem cells (ESCs, keratinocytes, and mucus cells; conversely, cell numbers were unaffected in MR knockdown morphants. In agreement, GR morphants, but not MR morphants, exhibited decreased NaRC-mediated Ca(2+ uptake and HRC-mediated H(+ secretion. Rescue via GR capped mRNA injection or exogenous cortisol incubation normalized the number of epidermal ionocytes in GR morphants. We also provide evidence for GR localization in epidermal cells. At the transcript level, GR mRNA is ubiquitously expressed in gill sections and present in both NaRCs and HRCs, supporting the knockdown and functional assay results in embryo. Altogether, we have provided solid molecular evidence that GR is indeed present on ionocytes, where it mediates the effects of cortisol on ionocyte development and function. Hence, cortisol-GR axis performs the roles of both GC and MC in zebrafish skin and gills.

  18. A novel ecdysone receptor mediates steroid-regulated developmental events during the mid-third instar of Drosophila.

    Directory of Open Access Journals (Sweden)

    Benjamin F B Costantino

    2008-06-01

    Full Text Available The larval salivary gland of Drosophila melanogaster synthesizes and secretes glue glycoproteins that cement developing animals to a solid surface during metamorphosis. The steroid hormone 20-hydroxyecdysone (20E is an essential signaling molecule that modulates most of the physiological functions of the larval gland. At the end of larval development, it is known that 20E--signaling through a nuclear receptor heterodimer consisting of EcR and USP--induces the early and late puffing cascade of the polytene chromosomes and causes the exocytosis of stored glue granules into the lumen of the gland. It has also been reported that an earlier pulse of hormone induces the temporally and spatially specific transcriptional activation of the glue genes; however, the receptor responsible for triggering this response has not been characterized. Here we show that the coordinated expression of the glue genes midway through the third instar is mediated by 20E acting to induce genes of the Broad Complex (BRC through a receptor that is not an EcR/USP heterodimer. This result is novel because it demonstrates for the first time that at least some 20E-mediated, mid-larval, developmental responses are controlled by an uncharacterized receptor that does not contain an RXR-like component.

  19. Vascular kinin B1 and B2 receptor-mediated effects in the rat isolated perfused kidney–differential regulations

    Science.gov (United States)

    Bagaté, Karim; Develioglu, Leyla; Imbs, Jean-Louis; Michel, Bruno; Helwig, Jean-Jacques; Barthelmebs, Mariette

    1999-01-01

    Bradykinin (BK) and analogs acting preferentially at kinin B1 or B2 receptors were tested on the rat isolated perfused kidney. Kidneys were perfused in an open circuit with Tyrode's solution. Kidneys preconstricted with prostaglandin F2α were used for the analysis of vasodilator responses.BK induced a concentration-dependent renal relaxation (pD2=8.9±0.4); this vasodilator response was reproduced by a selective B2 receptor agonist, Tyr(Me)8-BK (pD2=9.0±0.1) with a higher maximum effect (Emax=78.9±6.6 and 55.8±4.3% of ACh-induced relaxation respectively, n=6 and 19, P<0.02). Icatibant (10 nM), a selective B2 receptor antagonist, abolished BK-elicited relaxation. Tachyphylaxis of kinin B2 receptors appeared when repeatedly stimulated at 10 min intervals.Des-Arg9-BK, a selective B1 receptor agonist, induced concentration-dependent vasoconstriction at micromolar concentration. Maximum response was enhanced in the presence of lisinopril (1 μM) and inhibited by R 715 (8 μM), a selective B1 receptor antagonist. Des-Arg9-[Leu8]-BK behaved as an agonist.A contractile response to des-Arg9-BK occurred after 1 h of perfusion and increased with time by a factor of about three over a 3 h perfusion. This post-isolation sensitization to des-Arg9-BK was abolished by dexamethasone (DEX, 30 mg kg−1 i.p., 3 h before the start of the experiment and 10 μM in perfusate) and actinomycin D (2 μM). Acute exposure to DEX (10 μM) had no effect on sensitized des-Arg9-BK response, in contrast to indomethacin (30 μM) that abolished it. DEX pretreatment however had no effect on BK-induced renal vasodilation.Present results indicate that the main renal vascular response to BK consists of relaxation linked to the activation of kinin B2 receptors which rapidly desensitize. Renal B1 receptors are also present and are time-dependently sensitized during the in vitro perfusion of the rat kidneys. PMID:10588918

  20. Cholecystokinin-2 receptor mediated gene expression in neuronal PC12 cells

    DEFF Research Database (Denmark)

    Hansen, Thomas v O; Borup, Rehannah; Marstrand, Troels;

    2007-01-01

    Cholecystokinin (CCK) is abundantly expressed in the CNS, in which it regulates feeding behavior and long-term memory. Moreover, CCK has been implicated in mental disorders, such as anxiety and schizophrenia. Despite its manifest physiological and pathophysiological role, the molecular targets...... could be identified. Comparison with forskolin- and nerve growth factor (NGF)-treated PC12 cells showed that CCK induced a separate set of target genes. Taken together, we propose that neuronal CCK may have a role in the regulation of the circadian rhythm, the metabolism of cerebral cholesterol...

  1. Phenobarbital but not diazepam reduces AMPA/Kainate receptor mediated currents and exerts opposite actions on initial seizures in the neonatal rat hippocampus

    Directory of Open Access Journals (Sweden)

    Romain eNardou

    2011-07-01

    Full Text Available Diazepam (DZP and phenobarbital (PB are extensively used as first and second line drugs to treat acute seizures in neonates and their actions are thought to be mediated by increasing the actions of GABAergic signals. Yet, their efficacy is variable with occasional failure or even aggravation of recurrent seizures questioning whether other mechanisms are not involved in their actions. We have now compared the effects of DZP and PB on ictal-like events (ILEs in an in vitro model of mirror focus (MF. Using the three-compartment chamber with the two immature hippocampi and their commissural fibers placed in 3 different compartments, kainate was applied to one hippocampus and PB or DZP to the contralateral one, either after one ILE or after many recurrent ILEs that produce an epileptogenic MF. We report that in contrast to PB, DZP aggravated propagating ILEs from the start and did not prevent the formation of MF. PB reduced and DZP increased the network driven Giant Depolarising Potentials suggesting that PB may exert additional actions that are not mediated by GABA signalling. In keeping with this, PB but not DZP reduced field potentials recorded in the presence of GABA and NMDA receptor antagonists. These effects are mediated by a direct action on AMPA/Kainate receptors since PB: i reduced AMPA/Kainate receptor mediated currents induced by focal applications of glutamate ; ii reduced the amplitude and the frequency of AMPA but not NMDA receptor mediated miniature EPSCs; iii augmented the number of AMPA receptor mediated EPSCs failures evoked by minimal stimulation. These effects persisted in MF. Therefore, PB exerts its anticonvulsive actions partly by reducing AMPA/Kainate receptors mediated EPSCs in addition to the pro-GABA effects. We suggest that PB may have advantage over DZP in the treatment of initial neonatal seizures since the additional reduction of glutamate receptors mediated signals may reduce the severity of neonatal seizures.

  2. Kappa Opioid Receptors Mediate where Fear Is Expressed Following Extinction Training

    Science.gov (United States)

    Cole, Sindy; Richardson, Rick; McNally, Gavan P.

    2011-01-01

    Six experiments used a within-subjects renewal design to examine the involvement of kappa opioid receptors (KORs) in regulating the expression and recovery of extinguished fear. Rats were trained to fear a tone conditioned stimulus (CS) via pairings with foot shock in a distinctive context (A). This was followed by extinction training of the CS in…

  3. Characterization of murine melanocortin receptors mediating adipocyte lipolysis and examination of signalling pathways involved

    DEFF Research Database (Denmark)

    Møller, Cathrine Laustrup; Raun, Kirsten; Jacobsen, Marianne Lambert;

    2011-01-01

    The melanocortin receptors (MCRs) belong to the G-protein coupled receptors (family A). So far, 5 different subtypes have been described (MC1R-MC5R) and of these MC2R and MC5R have been proposed to act directly in adipocytes and regulate lipolysis in rodents. Using ACTH and a-melanocyte stimulating...

  4. Effects of receptor-mediated endocytosis and tubular protein composition on volume retention in experimental glomerulonephritis

    DEFF Research Database (Denmark)

    Kastner, Christian; Pohl, Marcus; Sendeski, Mauricio;

    2009-01-01

    and channels involved in volume regulation were altered in GN, and 2) proximal tubular endocytosis may influence locally as well as downstream expressed tubular transporters and channels. Effects of anti-glomerular basement membrane GN were studied in controls and megalin-deficient mice with blunted proximal...

  5. Intrinsically disordered cytoplasmic domains of two cytokine receptors mediate conserved interactions with membranes

    DEFF Research Database (Denmark)

    Haxholm, Gitte Wolfsberg; Nikolajsen, Louise Fletcher; Olsen, Johan Gotthardt;

    2015-01-01

    Class 1 cytokine receptors regulate essential biological processes through complex intracellular signaling networks. However, the structural platform for understanding their functions is currently incomplete as structure-function studies of the intracellular domains (ICDs) are critically lacking...... of the inner plasma membrane leaflet through conserved motifs resembling immuno T-cell receptor activation motifs(ITAMs). However, contrary to the observations made for ITAMs, lipid association of the prolactin and growth hormone receptor ICDs was shown to be unaccompanied by changes in transient secondary...... structure and independent of tyrosine phosphorylation. The data presented here provides a new structural platform for studying class 1 cytokine receptors and may implicate the membrane as an active component regulating intracellular signaling....

  6. Role of desensitization and subunit expression for kainate receptor-mediated neurotoxicity in murine neocortical cultures

    DEFF Research Database (Denmark)

    Jensen, J B; Schousboe, A; Pickering, D S;

    1999-01-01

    The neurotoxic actions of kainate and domoate were studied in cultured murine neocortical neurons at various days in culture and found to be developmentally regulated involving three components of neurotoxicity: (1) toxicity via indirect activation of N-methyl-D-aspartate (NMDA) receptors, (2) to...... produced by kainate receptors in mature cultures. Examining the subunit expression of the kainate receptor subunits GluR6/7 and KA2 did, however, not reveal any major change during development of the cultures....

  7. Icariin Stimulates Differentiation and Suppresses Adipocytic Transdifferentiation of Primary Osteoblasts Through Estrogen Receptor-Mediated Pathway.

    Science.gov (United States)

    Zhang, Dawei; Fong, Chichun; Jia, Zhenbin; Cui, Liao; Yao, Xinsheng; Yang, Mengsu

    2016-08-01

    Icariin, the main constituent of Herba Epimedii, appears to be a promising alternative to classic drugs used to treat osteoporosis. However, the detailed molecular mechanisms of its action and the role of icariin in the cross-talk between osteoblasts and adipocytes remain unclear. The present study was designed to investigate the gene expression profile of primary osteoblasts in the presence of icariin, and the effects of icariin on the differentiation and adipogenic transdifferentiation of osteoblasts. Cellular and molecular markers expressed during osteoblastic differentiation were assessed by cytochemical analysis, real-time quantitative PCR, Western blotting, and cDNA microarray analysis. Results indicated that icariin up-regulated the expression of runt-related transcription factor 2 (Runx2), bone morphogenetic protein 2 (Bmp2), and collagen type 1 (Col1) genes, and down-regulated the expression of the peroxisome proliferator-activated receptor γ (Pparg) and CCAAT/enhancer-binding protein β (Cebpb) genes. These effects were blocked by ICI 182,780, suggesting that icariin may be acting via the estrogen receptor (ER). Results also demonstrated that the ratio of osteoprotegerin (Opg)/receptor activator of nuclear factor kappa B ligand (Rankl) expression was up-regulated following treatment with icariin. In total, osteoblastic gene expression profile analysis suggested that 33 genes were affected by icariin; these could be sub-divided into nine functional categories. It appears that icariin could stimulate the differentiation and mineralization of osteoblasts, regulate the differentiation of osteoclasts, and inhibit the adipogenic transdifferentiation of osteoblasts, therefore increasing the number of osteoblasts undergoing differentiation to mature osteoblasts, via an ER-mediated pathway. In summary, icariin may exhibit beneficial effects on bone health, especially for patients with osteoporosis and obesity. PMID:27061090

  8. Genetically designed biomolecular capping system for mesoporous silica nanoparticles enables receptor-mediated cell uptake and controlled drug release

    Science.gov (United States)

    Datz, Stefan; Argyo, Christian; Gattner, Michael; Weiss, Veronika; Brunner, Korbinian; Bretzler, Johanna; von Schirnding, Constantin; Torrano, Adriano A.; Spada, Fabio; Vrabel, Milan; Engelke, Hanna; Bräuchle, Christoph; Carell, Thomas; Bein, Thomas

    2016-04-01

    Effective and controlled drug delivery systems with on-demand release and targeting abilities have received enormous attention for biomedical applications. Here, we describe a novel enzyme-based cap system for mesoporous silica nanoparticles (MSNs) that is directly combined with a targeting ligand via bio-orthogonal click chemistry. The capping system is based on the pH-responsive binding of an aryl-sulfonamide-functionalized MSN and the enzyme carbonic anhydrase (CA). An unnatural amino acid (UAA) containing a norbornene moiety was genetically incorporated into CA. This UAA allowed for the site-specific bio-orthogonal attachment of even very sensitive targeting ligands such as folic acid and anandamide. This leads to specific receptor-mediated cell and stem cell uptake. We demonstrate the successful delivery and release of the chemotherapeutic agent Actinomycin D to KB cells. This novel nanocarrier concept provides a promising platform for the development of precisely controllable and highly modular theranostic systems.Effective and controlled drug delivery systems with on-demand release and targeting abilities have received enormous attention for biomedical applications. Here, we describe a novel enzyme-based cap system for mesoporous silica nanoparticles (MSNs) that is directly combined with a targeting ligand via bio-orthogonal click chemistry. The capping system is based on the pH-responsive binding of an aryl-sulfonamide-functionalized MSN and the enzyme carbonic anhydrase (CA). An unnatural amino acid (UAA) containing a norbornene moiety was genetically incorporated into CA. This UAA allowed for the site-specific bio-orthogonal attachment of even very sensitive targeting ligands such as folic acid and anandamide. This leads to specific receptor-mediated cell and stem cell uptake. We demonstrate the successful delivery and release of the chemotherapeutic agent Actinomycin D to KB cells. This novel nanocarrier concept provides a promising platform for the

  9. MicroRNA-219 modulates NMDA receptor-mediated neurobehavioral dysfunction

    DEFF Research Database (Denmark)

    Kocerha, Jannet; Faghihi, Mohammad Ali; Lopez-Toledano, Miguel A;

    2009-01-01

    N-methyl-D-aspartate (NMDA) glutamate receptors are regulators of fast neurotransmission and synaptic plasticity in the brain. Disruption of NMDA-mediated glutamate signaling has been linked to behavioral deficits displayed in psychiatric disorders such as schizophrenia. Recently, noncoding RNA...... significantly modulated behavioral responses associated with disrupted NMDA receptor transmission. Furthermore, pretreatment with the antipsychotic drugs haloperidol and clozapine prevented dizocilpine-induced effects on miR-219. Taken together, these data support an integral role for miR-219 in the expression...

  10. Stromal estrogen receptors mediate mitogenic effects of estradiol on uterine epithelium

    OpenAIRE

    Cooke, P S; Buchanan, D. L.; Young, P.; Setiawan, T.; Brody, J.; Korach, K S; Taylor, J; Lubahn, D.B.; Cunha, G R

    1997-01-01

    Estradiol-17β (E2) acts through the estrogen receptor (ER) to regulate uterine growth and functional differentiation. To determine whether E2 elicits epithelial mitogenesis through epithelial ER versus indirectly via ER-positive stromal cells, uteri from adult ER-deficient ER knockout (ko) mice and neonatal ER-positive wild-type (wt) BALB/c mice were used to produce the following tissue recombinants containing ER in epithelium (E) and/or stroma (S), or lacking ER altogether: wt-S + wt-E, wt-S...

  11. The nuclear architectural protein HMGA1a triggers receptor-mediated endocytosis.

    Science.gov (United States)

    Wu, Wuwei; Wan, Wei; Li, Alexander D Q

    2009-11-01

    High mobility group proteins A (HMGA), nuclear architectural factors, locate in the cell nuclei and mostly execute gene-regulation function. However, our results reveal that a HMGA member (HMGA1a) has a unique plasma membrane receptor; this receptor specifically binds to HMGA-decorated species, effectively mediates endocytosis, and internalizes extracellular HMGA-functionalized cargoes. Indeed, dyes or nanoparticles labeled with HMGA1a protein readily enter Hela cells. Using a stratagem chemical cross-linker, we covalently bonded the HMGA receptor to the HMGA1a-GFP fusion protein, thus capturing the plasma membrane receptor. Subsequent Western blots and SDS-PAGE gel revealed that the HMGA receptor is a 26-kDa protein. Confocal live-cell microscopic imaging was used to monitor the whole endocytic process, in which the internalized HMGA1a-decorated species are transported by motor proteins on microtubules and eventually arrive at the late endosomes/lysosomes. Cell viability assays also suggested that extracellular HMGA1a protein directly influences the survival ability of Hela cells in a dose-dependent manner, implying versatility of HMGA1a protein and its potent role to suppress cancer cell survivability and to regulate growth. PMID:19739099

  12. Metabotropic glutamate receptor-mediated signaling dampens the HPA axis response to restraint stress.

    Science.gov (United States)

    Evanson, Nathan K; Herman, James P

    2015-10-15

    Glutamate is an important neurotransmitter in the regulation of the neural portion of hypothalamus-pituitary-adrenal (HPA) axis activity, and signals through ionotropic and metabotropic receptors. In the current studies we investigated the role of hypothalamic paraventricular group I metabotropic glutamate receptors in the regulation of the HPA axis response to restraint stress in rats. Direct injection of the group I metabotropic glutamate receptor agonist 3,5-dihydroxyphenylglycine (DHPG) into the PVN prior to restraint leads to blunting of the HPA axis response in awake animals. Consistent with this result, infusion of the group I receptor antagonist hexyl-homoibotenic acid (HIBO) potentiates the HPA axis response to restraint. The excitatory effect of blocking paraventricular group I metabotropic glutamate signaling is blocked by co-administration of dexamethasone into the PVN. However, the inhibitory effect of DHPG is not affected by co-administration of the cannabinoid CB1 receptor antagonist AM-251 into the PVN. Together, these results suggest that paraventricular group I metabotropic glutamate receptor signaling acts to dampen HPA axis reactivity. This effect appears to be similar to the rapid inhibitory effect of glucocorticoids at the PVN, but is not mediated by endocannabinoid signaling.

  13. ARRHYTHMOGENIC CALMODULIN MUTATIONS AFFECT THE ACTIVATION AND TERMINATION OF CARDIAC RYANODINE RECEPTOR MEDIATED CA2+ RELEASE

    DEFF Research Database (Denmark)

    Søndergaard, Mads Toft; Chazin, Walter J.; Chen, Wayne S.R.;

    We recently identified the first two human missense mutations in a calmodulin (CaM) gene (CALM1) and linked these to catecholaminergic polymorphic ventricular tachycardia (CPVT) and sudden cardiac death in young individuals1. More CaM mutations have since been identified in CALM1 and also...... in the other two CaM genes (CALM2 and CALM3). All CaM mutations are associated with severe ventricular arrhythmias. CaM regulates several key proteins governing cardiac excitation-contraction coupling (ECC), including the cardiac ryanodine receptor (RyR2) Ca2+ release channel. RyR2 mutations also dominantly...... cause CPVT, where the mutations increase the channel sensitivity to activation and enhance the propensity for pro-arrhythmogenic spontaneous Ca2+ release. Here we investigated the effect of CPVT-linked CaM mutations (N53I and N97S) and two CaM mutations identified in individuals with early onset severe...

  14. Nuclear-receptor-mediated telomere insertion leads to genome instability in ALT cancers.

    Science.gov (United States)

    Marzec, Paulina; Armenise, Claudia; Pérot, Gaëlle; Roumelioti, Fani-Marlen; Basyuk, Eugenia; Gagos, Sarantis; Chibon, Frédéric; Déjardin, Jérôme

    2015-02-26

    The breakage-fusion-bridge cycle is a classical mechanism of telomere-driven genome instability in which dysfunctional telomeres are fused to other chromosomal extremities, creating dicentric chromosomes that eventually break at mitosis. Here, we uncover a distinct pathway of telomere-driven genome instability, specifically occurring in cells that maintain telomeres with the alternative lengthening of telomeres mechanism. We show that, in these cells, telomeric DNA is added to multiple discrete sites throughout the genome, corresponding to regions regulated by NR2C/F transcription factors. These proteins drive local telomere DNA addition by recruiting telomeric chromatin. This mechanism, which we name targeted telomere insertion (TTI), generates potential common fragile sites that destabilize the genome. We propose that TTI driven by NR2C/F proteins contributes to the formation of complex karyotypes in ALT tumors. PMID:25723166

  15. Rapidly activated epidermal growth factor receptor mediates lipopolysaccharide-triggered migration of microglia.

    Science.gov (United States)

    Qu, Wen-Sheng; Liu, Jun-Li; Li, Chun-Yu; Li, Xiao; Xie, Min-Jie; Wang, Wei; Tian, Dai-Shi

    2015-11-01

    Previous reports have suggested that epidermal growth factor receptor (EGFR) is involved in microglia activation characterized by cell morphology changes, cytokine production and cell migration; and the biochemical regulation of the microglia migration is a potential therapeutic target following CNS inflammatory damages. However, the role of EGFR in microglia motility after inflammatory stimulation remains unknown. In the present study, lipopolysaccharide (LPS) was found to trigger rapid EGFR phosphorylation within 10 min, which was sustained during long-term stimulation in both primary microglial cells and the cultured BV2 microglial cells, furthermore, blocking EGFR phosphorylation by AG1478 significantly attenuated the LPS-induced chemotactic and chemokinetic migration of microglia. In addition, LPS could initiate calcium oscillation in microglia during live-cell recording, however, an intracellular calcium chelator and a selective inhibitor of calcium/calmodulin-dependent protein kinase II, but not an extracellular calcium chelator, remarkably suppressed the LPS-induced EGFR phosphorylation in BV2 microglia cells. As EGFR is not a traditional receptor for LPS, these findings suggest that the rapid phosphorylation of EGFR is attributed to the LPS-triggered intracellular calcium mobilization. By examining the downstream signals of EGFR, we further proved that extracellular signal-regulated kinase (ERK) is essential for EGFR-mediated microglia migration, because ERK inhibition attenuated the chemotactic and chemokinetic migration of microglia that had been induced by either LPS or EGF. Collectively, these results suggest that LPS could trigger the rapid phosphorylation of EGFR and subsequent ERK activation through mobilizing calcium activity, which underlies the microglia migration in an inflammatory condition.

  16. Ionotropic glutamate receptors mediate inducible defense in the water flea Daphnia pulex.

    Directory of Open Access Journals (Sweden)

    Hitoshi Miyakawa

    Full Text Available Phenotypic plasticity is the ability held in many organisms to produce different phenotypes with a given genome in response to environmental stimuli, such as temperature, nutrition and various biological interactions. It seems likely that environmental signals induce a variety of mechanistic responses that influence ontogenetic processes. Inducible defenses, in which prey animals alter their morphology, behavior and/or other traits to help protect against direct or latent predation threats, are among the most striking examples of phenotypic plasticity. The freshwater microcrustacean Daphnia pulex forms tooth-like defensive structures, "neckteeth," in response to chemical cues or signals, referred to as "kairomones," in this case released from phantom midge larvae, a predator of D. pulex. To identify factors involved in the reception and/or transmission of a kairomone, we used microarray analysis to identify genes up-regulated following a short period of exposure to the midge kairomone. In addition to identifying differentially expressed genes of unknown function, we also found significant up-regulation of genes encoding ionotropic glutamate receptors, which are known to be involved in neurotransmission in many animal species. Specific antagonists of these receptors strongly inhibit the formation of neckteeth in D. pulex, although agonists did not induce neckteeth by themselves, indicating that ionotropic glutamate receptors are necessary but not sufficient for early steps of neckteeth formation in D. pulex. Moreover, using co-exposure of D. pulex to antagonists and juvenile hormone (JH, which physiologically mediates neckteeth formation, we found evidence suggesting that the inhibitory effect of antagonists is not due to direct inhibition of JH synthesis/secretion. Our findings not only provide a candidate molecule required for the inducible defense response in D. pulex, but also will contribute to the understanding of complex mechanisms

  17. Angiotensin II Type 1 Receptor-Mediated Electrical Remodeling in Mouse Cardiac Myocytes.

    Directory of Open Access Journals (Sweden)

    Jeremy Kim

    Full Text Available We recently characterized an autocrine renin angiotensin system (RAS in canine heart. Activation of Angiotensin II Type 1 Receptors (AT1Rs induced electrical remodeling, including inhibition of the transient outward potassium current Ito, prolongation of the action potential (AP, increased calcium entry and increased contractility. Electrical properties of the mouse heart are very different from those of dog heart, but if a similar system existed in mouse, it could be uniquely studied through genetic manipulations. To investigate the presence of a RAS in mouse, we measured APs and Ito in isolated myocytes. Application of angiotensin II (A2 for 2 or more hours reduced Ito magnitude, without affecting voltage dependence, and prolonged APs in a dose-dependent manner. Based on dose-inhibition curves, the fast and slow components of Ito (Ito,fast and IK,slow appeared to be coherently regulated by [A2], with 50% inhibition at an A2 concentration of about 400 nM. This very high K0.5 is inconsistent with systemic A2 effects, but is consistent with an autocrine RAS in mouse heart. Pre-application of the microtubule destabilizing agent colchicine eliminated A2 effects on Ito and AP duration, suggesting these effects depend on intracellular trafficking. Application of the biased agonist SII ([Sar1-Ile4-Ile8]A2, which stimulates receptor internalization without G protein activation, caused Ito reduction and AP prolongation similar to A2-induced changes. These data demonstrate AT1R mediated regulation of Ito in mouse heart. Moreover, all measured properties parallel those measured in dog heart, suggesting an autocrine RAS may be a fundamental feedback system that is present across species.

  18. Histaminergic H1 receptors mediate L-histidine-induced anxiety in elevated plus-maze test in mice.

    Science.gov (United States)

    Kumar, Kuchibhotla Vijaya; Krishna, Devarakonda Rama; Palit, Gautam

    2007-05-01

    The central histaminergic system is reported to mediate behavioural, hormonal and physiological homeostasis of living organisms. Recent reports indicate its prominent role in various neurobehavioural disorders such as depression and psychosis. This study evaluated the effect of activation of the central histaminergic system in anxiety-like conditions, using the elevated plus-maze test in mice, and elucidated the role of different histaminergic receptors mediating such effects. Peripheral administration of L-histidine (L-His), in a dose-dependent manner, significantly decreased the exploration time in open arms and number of entries into open arms without modifying the number of entries into closed arms of the elevated plus-maze, indicating anxiogenesis. Further, such effects of central histamine were significantly attenuated, in a dose-dependent manner, by pretreatment with pyrilamine (H1 receptor antagonist). Pretreatment with either zolantidine (H2 receptor antagonist) or thioperamide (H3 receptor antagonist), however, failed to attenuate the L-His-induced anxiogenesis. Our results indicate that anxiogenic effects of central histaminergic system appear to be mediated prominently by activation of H1 receptors.

  19. Polypeptide hormone receptor phosphorylation: is there a role in receptor-mediated endocytosis of human growth hormone

    International Nuclear Information System (INIS)

    To determine whether receptor phosphorylation is a critical step in the internalization of polypeptide hormones and their receptors, the authors have studied a model system wherein insulin stimulates phosphorylation of its receptor and is also internalized. Using insulin as a positive control, they found that it stimulated a partially purified plasma membrane preparation of IM-9 lymphocytes to autophosphorylate its receptor and to catalyze the phosphorylation of a tyrosine-containing substrate. The human GH (hGH) receptor of the IM-9 lymphocytes, when coupled to [125I]iodo-hGH, migrated as a 140,000-dalton protein on polyacrylamide gel electrophoresis. This protein, in contrast to the insulin receptor, was not phosphorylated by the addition of hGH, nor did hGH stimulate this preparation to phosphorylate the tyrosine-containing substrate poly-(GluNa,Tyr)4:1, casein, or histone f2b under a variety of conditions. The authors conclude that receptor phosphorylation is not a critical intermediate in the receptor-mediated endocytosis of hGH and probably other polypeptide hormones and growth factors

  20. An special epithelial staining agents: folic acid receptor-mediated diagnosis (FRD) effectively and conveniently screen patients with cervical cancer.

    Science.gov (United States)

    Lu, Meng-Han; Hu, Ling-Yun; Du, Xin-Xin; Yang, Min; Zhang, Wei-Yi; Huang, Ke; Li, Li-An; Jiang, Shu-Fang; Li, Ya-Li

    2015-01-01

    High-quality screening with cytology has markedly reduced mortality from cervical cancer. However, it needs experienced pathologists to review and make the final decisions. We have developed folic acid receptor-mediated diagnosis (FRD) kits to effectively and conveniently screen patients with cervical cancer. We conduct present study aim to assess clinical significances of FRD in screening cervical cancer. A total of 169 patients were enrolled at Chinese People's liberation Army (PLA) general hospital. We compared diagnostic significances of FRD with thinprep cytology test (TCT). Meanwhile, colposcopy was also performed to confirm any lesion suspicious for cervical cancer. The sensitivity and specificity of FRD were 71.93% and 66.07% in diagnosis cervical cancer, respectively. Meanwhile, the positive predictive values (PPV), negative predictive values (NPV), Youden index were 51.90%, 82.22%, 0.38, respectively. On the other hand, the sensitivity and specificity of TCT in diagnosis cervical cancer were 73.68% and 61.61% respectively. PPV, NPV and Youden index for TCT were 49.41%, 82.14% and 0.35 respectively. Overall, FRD have high values of sensitivity, specificity and Youden index. However, this difference failed to statistical significance. FRD have comparable diagnostic significance with TCT. Therefore, FRD might serve as one effective method to screen cervical cancer. Especially for those patients living in remote regions of China, where cytology was unavailable.

  1. The overexpressed human 46-kDa mannose 6-phosphate receptor mediates endocytosis and sorting of β-glucuronidase

    International Nuclear Information System (INIS)

    The authors studied the function of the human small (46-kDa) mannose 6-phosphate receptor (SMPR) in transfected mouse L cells that do not express the larger insulin-like growth factor II/mannose 6-phosphate receptor. Cells overexpressing human SMPR were studied for enzyme binding to cell surface receptors, for binding to intracellular receptors in permeabilized cells, and for receptor-mediated endocytosis of recombinant human β-glucuronidase. Specific binding to human SMPR in permeabilized cells showed a pH optimum between pH 6.0 and pH 6.5. Binding was significant in the present of EDTA but was enhanced by added divalent cations. Up to 2.3% of the total functional receptor could be detected on the cell surface by enzyme binding. They present experiments showing that at very high levels of overexpression, and at pH 6.5, human SMPR mediated the endocytosis of β-glucuronidase. At pH 7.5, the rate of endocytosis was only 14% the rate seen at pH 6.5. Cells overexpressing human SMPR also showed reduced secretion of newly synthesized β-glucuronidase when compared to cells transfected with vector only, suggesting that overexpressed human SMPR can participate in sorting of newly synthesized β-glucuronidase and partially correct the sorting defect in mouse L cells that do not express the insulin-like growth factor II/mannose 6-phosphate receptor

  2. Interrogating the Role of Receptor-Mediated Mechanisms: Biological Fate of Peptide-Functionalized Radiolabeled Gold Nanoparticles in Tumor Mice.

    Science.gov (United States)

    Silva, Francisco; Zambre, Ajit; Campello, Maria Paula Cabral; Gano, Lurdes; Santos, Isabel; Ferraria, Ana Maria; Ferreira, Maria João; Singh, Amolak; Upendran, Anandhi; Paulo, António; Kannan, Raghuraman

    2016-04-20

    To get a better insight on the transport mechanism of peptide-conjugated nanoparticles to tumors, we performed in vivo biological studies of bombesin (BBN) peptide functionalized gold nanoparticles (AuNPs) in human prostate tumor bearing mice. Initially, we sought to compare AuNPs with thiol derivatives of acyclic and macrocyclic chelators of DTPA and DOTA types. The DTPA derivatives were unable to provide a stable coordination of (67)Ga, and therefore, the functionalization with the BBN analogues was pursued for the DOTA-containing AuNPs. The DOTA-coated AuNPs were functionalized with BBN[7-14] using a unidentate cysteine group or a bidentate thioctic group to attach the peptide. AuNPs functionalized with thioctic-BBN displayed the highest in vitro cellular internalization (≈ 25%, 15 min) in gastrin releasing peptide (GRP) receptor expressing cancer cells. However, these results fail to translate to in vivo tumor uptake. Biodistribution studies following intravenous (IV) and intraperitoneal (IP) administration of nanoconjugates in tumor bearing mice indicated that the presence of BBN influences to some degree the biological profile of the nanoconstructs. For IV administration, the receptor-mediated pathway appears to be outweighed by the EPR effect. By contrast, in IP administration, it is reasoned that the GRPr-mediated mechanism plays a role in pancreas uptake. PMID:27003101

  3. Receptor-mediated membrane adhesion of lipid-polymer hybrid (LPH) nanoparticles studied by dissipative particle dynamics simulations

    Science.gov (United States)

    Li, Zhenlong; Gorfe, Alemayehu A.

    2014-12-01

    Lipid-polymer hybrid (LPH) nanoparticles represent a novel class of targeted drug delivery platforms that combine the advantages of liposomes and biodegradable polymeric nanoparticles. However, the molecular details of the interaction between LPHs and their target cell membranes remain poorly understood. We have investigated the receptor-mediated membrane adhesion process of a ligand-tethered LPH nanoparticle using extensive dissipative particle dynamics (DPD) simulations. We found that the spontaneous adhesion process follows a first-order kinetics characterized by two distinct stages: a rapid nanoparticle-membrane engagement, followed by a slow growth in the number of ligand-receptor pairs coupled with structural re-organization of both the nanoparticle and the membrane. The number of ligand-receptor pairs increases with the dynamic segregation of ligands and receptors toward the adhesion zone causing an out-of-plane deformation of the membrane. Moreover, the fluidity of the lipid shell allows for strong nanoparticle-membrane interactions to occur even when the ligand density is low. The LPH-membrane avidity is enhanced by the increased stability of each receptor-ligand pair due to the geometric confinement and the cooperative effect arising from multiple binding events. Thus, our results reveal the unique advantages of LPH nanoparticles as active cell-targeting nanocarriers and provide some general principles governing nanoparticle-cell interactions that may aid future design of LPHs with improved affinity and specificity for a given target of interest.

  4. Estrogen receptor-mediated transcription involves the activation of multiple kinase pathways in neuroblastoma cells.

    Science.gov (United States)

    Clark, Sara; Rainville, Jennifer; Zhao, Xing; Katzenellenbogen, Benita S; Pfaff, Donald; Vasudevan, Nandini

    2014-01-01

    While many physiological effects of estrogens (E) are due to regulation of gene transcription by liganded estrogen receptors (ERs), several effects are also mediated, at least in part, by rapid non-genomic actions of E. Though the relative importance of rapid versus genomic effects in the central nervous system is controversial, we showed previously that membrane-limited effects of E, initiated by an estradiol bovine serum albumin conjugate (E2-BSA), could potentiate transcriptional effects of 17β-estradiol from an estrogen response element (ERE)-reporter in neuroblastoma cells. Here, using specific inhibitors and activators in a pharmacological approach, we show that activation of phosphatidylinositol-3-phosphate kinase (PI3K) and mitogen activated protein kinase (MAPK) pathways, dependent on a Gαq coupled receptor signaling are important in this transcriptional potentiation. We further demonstrate, using ERα phospho-deficient mutants, that E2-BSA mediated phosphorylation of ERα is one mechanism to potentiate transcription from an ERE reporter construct. This study provides a possible mechanism by which signaling from the membrane is coupled to transcription in the nucleus, providing an integrated view of hormone signaling in the brain.

  5. Pax6 represses androgen receptor-mediated transactivation by inhibiting recruitment of the coactivator SPBP.

    Directory of Open Access Journals (Sweden)

    Julianne Elvenes

    Full Text Available The androgen receptor (AR has a central role in development and maintenance of the male reproductive system and in the etiology of prostate cancer. The transcription factor Pax6 has recently been reported to act as a repressor of AR and to be hypermethylated in prostate cancer cells. SPBP is a transcriptional regulator that previously has been shown to enhance the activity of Pax6. In this study we have identified SPBP to act as a transcriptional coactivator of AR. We also show that Pax6 inhibits SPBP-mediated enhancement of AR activity on the AR target gene probasin promoter, a repression that was partly reversed by increased expression of SPBP. Enhanced expression of Pax6 reduced the amount of SPBP associated with the probasin promoter when assayed by ChIP in HeLa cells. We mapped the interaction between both AR and SPBP, and AR and Pax6 to the DNA-binding domains of the involved proteins. Further binding studies revealed that Pax6 and SPBP compete for binding to AR. These results suggest that Pax6 represses AR activity by displacing and/or inhibiting recruitment of coactivators to AR target promoters. Understanding the mechanism for inhibition of AR coactivators can give rise to molecular targeted drugs for treatment of prostate cancer.

  6. Cannabinoid CB2 receptor-mediated anti-nociception in models of acute and chronic pain.

    Science.gov (United States)

    Jhaveri, Maulik D; Sagar, Devi R; Elmes, Steven J R; Kendall, David A; Chapman, Victoria

    2007-08-01

    The endocannabinoid system consists of cannabinoid CB(1) and CB(2) receptors, endogenous ligands and their synthesising/metabolising enzymes. Cannabinoid receptors are present at key sites involved in the relay and modulation of nociceptive information. The analgesic effects of cannabinoids have been well documented. The usefulness of nonselective cannabinoid agonists can, however, be limited by psychoactive side effects associated with activation of CB(1) receptors. Following the recent evidence for CB(2) receptors existing in the nervous system and reports of their up-regulation in chronic pain states and neurodegenerative diseases, much research is now aimed at shedding light on the role of the CB(2) receptor in human disease. Recent studies have demonstrated anti-nociceptive effects of selective CB(2) receptor agonists in animal models of pain in the absence of CNS side effects. This review focuses on the analgesic potential of CB(2) receptor agonists for inflammatory, post-operative and neuropathic pain states and discusses their possible sites and mechanisms of action.

  7. Emodin isolated from Polygoni Multiflori Ramulus inhibits melanogenesis through the liver X receptor-mediated pathway.

    Science.gov (United States)

    Kim, Mi Ok; Park, Yong Seek; Nho, Youn Hwa; Yun, Seok Kyun; Kim, Youngsoo; Jung, Eunsun; Paik, Jean Kyung; Kim, Minhee; Cho, Il-Hoon; Lee, Jongsung

    2016-04-25

    Melanogenesis is a physiological process that results in the synthesis of melanin pigments, which play a crucial protective role against skin photocarcinogenesis. We investigated the effects of a Polygoni Multiflori Ramulus extract on melanogenesis and isolated emodin from Polygoni Multiflori as an active compound. In addition, the possible mechanisms of action were examined. We found that emodin inhibited both melanin content and tyrosinase activity concentration and time dependently. Tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 mRNA levels decreased following emodin treatment. However, while the mRNA levels of microphthalmia-associated transcription factor (MITF) were not affected by emodin, emodin reduced MITF protein levels. Furthermore, expression of the liver X-receptor (LXR) α gene, but not the LXR β gene was upregulated by emodin. Moreover, emodin regulated melanogenesis by promoting degradation of the MITF protein by upregulating the LXR α gene. The emodin effects on MITF was found to be mediated by phosphorylation of p42/44 MAPK. Taken together, these findings indicate that the inhibition of melanogenesis by emodin occurs through reduced MITF protein expression, which is mediated by upregulation of the LXR α gene and suggest that emodin may be useful as a hyperpigmentation inhibitor. PMID:26972667

  8. CXCR4 Chemokine Receptor Mediates Prostate Tumor Cell Adhesion through α5 and β3 Integrins

    Directory of Open Access Journals (Sweden)

    Tobias Engl

    2006-04-01

    Full Text Available The mechanisms leading to prostate cancer metastasis are not understood completely. Although there is evidence that the CXC chemokine receptor (CXCR 4 and its ligand CXCL12 may regulate tumor dissemination, their role in prostate cancer is controversial. We examined CXCR4 expression and functionality, and explored CXCL12-triggered adhesion of prostate tumor cells to human endothelium or to extracellular matrix proteins laminin, collagen, and fibronectin. Although little CXCR4 was expressed on LNCaP and DU-145 prostate tumor cells, CXCR4 was still active, enabling the cells to migrate toward a CXCL12 gradient. CXCL12 induced elevated adhesion to the endothelial cell monolayer and to immobilized fibronectin, laminin, and collagen. Anti-CXCR4 antibodies or CXCR4 knock out significantly impaired CXCL 12-triggered tumor cell binding. The effects observed did not depend on CXCR4 surface expression level. Rather, CXCR4-mediated adhesion was established by α5 and β3 integrin subunits and took place in the presence of reduced p38 and p38 phosphorylation. These data show that chemoattractive mechanisms are involved in adhesion processes of prostate cancer cells, and that binding of CXCL12 to its receptor leads to enhanced expression of α5 and β3. The findings provide a link between chemokine receptor expression and integrin-triggered tumor dissemination.

  9. Toll-like receptor-mediated immune response inhibits prion propagation.

    Science.gov (United States)

    Kang, Sang-Gyun; Kim, Chiye; Cortez, Leonardo M; Carmen Garza, María; Yang, Jing; Wille, Holger; Sim, Valerie L; Westaway, David; McKenzie, Debbie; Aiken, Judd

    2016-06-01

    Prion diseases are progressive neurodegenerative disorders affecting humans and various mammals. The prominent neuropathological change in prion diseases is neuroinflammation characterized by activation of neuroglia surrounding prion deposition. The cause and effect of this cellular response, however, is unclear. We investigated innate immune defenses against prion infection using primary mixed neuronal and glial cultures. Conditional prion propagation occurred in glial cultures depending on their immune status. Preconditioning of the cells with the toll-like receptor (TLR) ligand, lipopolysaccharide, resulted in a reduction in prion propagation, whereas suppression of the immune responses with the synthetic glucocorticoid, dexamethasone, increased prion propagation. In response to recombinant prion fibrils, glial cells up-regulated TLRs (TLR1 and TLR2) expression and secreted cytokines (tumor necrosis factor-α, interleukin-1β, interleukin-6, granulocyte-macrophage colony-stimulating factor, and interferon-β). Preconditioning of neuronal and glial cultures with recombinant prion fibrils inhibited prion replication and altered microglial and astrocytic populations. Our results provide evidence that, in early stages of prion infection, glial cells respond to prion infection through TLR-mediated innate immunity. GLIA 2016;64:937-951. PMID:26880394

  10. Alpha-latrotoxin modulates the secretory machinery via receptor-mediated activation of protein kinase C.

    Science.gov (United States)

    Liu, Jie; Wan, Qunfang; Lin, Xianguang; Zhu, Hongliang; Volynski, Kirill; Ushkaryov, Yuri; Xu, Tao

    2005-09-01

    The hypothesis whether alpha-latrotoxin (LTX) could directly regulate the secretory machinery was tested in pancreatic beta cells using combined techniques of membrane capacitance (Cm) measurement and Ca2+ uncaging. Employing ramp increase in [Ca2+]i to stimulate exocytosis, we found that LTX lowers the Ca2+ threshold required for exocytosis without affecting the size of the readily releasable pool (RRP). The burst component of exocytosis in response to step-like [Ca2+]i increase generated by flash photolysis of caged Ca2+ was also speeded up by LTX treatment. LTX increased the maximum rate of exocytosis compared with control responses with similar postflash [Ca2+]i and shifted the Ca2+ dependence of the exocytotic machinery toward lower Ca2+ concentrations. LTXN4C, a LTX mutant which cannot form membrane pores or penetrate through the plasma membrane but has similar affinity for the receptors as the wild-type LTX, mimicked the effect of LTX. Moreover, the effects of both LTX and LTXN4C) were independent of intracellular or extracellular Ca2+ but required extracellular Mg2+. Our data propose that LTX, by binding to the membrane receptors, sensitizes the fusion machinery to Ca2+ and, hence, may permit release at low [Ca2+]i level. This sensitization is mediated by activation of protein kinase C. PMID:16101679

  11. Preparation and characterization of folate-poly(ethylene glycol)-grafted-trimethylchitosan for intracellular transport of protein through folate receptor-mediated endocytosis.

    Science.gov (United States)

    Zheng, Yu; Song, Xiangrong; Darby, Michael; Liang, Yufeng; He, Ling; Cai, Zheng; Chen, Qiuhong; Bi, Yueqi; Yang, Xiaojuan; Xu, Jiapeng; Li, Yuanbo; Sun, Yiyi; Lee, Robert J; Hou, Shixiang

    2010-01-01

    To develop a receptor-mediated intracellular delivery system that can transport therapeutic proteins to specific tumor cells, folate-poly(ethylene glycol)-grafted-trimethylchitosan (folate-PEG-g-TMC) was synthesized. Nano-scaled spherical polyelectrolyte complexes between the folate-PEG-g-TMC and fluorescein isothiocyanate conjugated bovine serum albumin (FITC-BSA) were prepared under suitable weight ratio of copolymer to FITC-BSA by ionic interaction between the positively charged copolymers and the negatively charged FITC-BSA. Intracellular uptake of FITC-BSA was specifically enhanced in SKOV3 cells (folate receptor over-expressing cell line) through folate receptor-mediated endocytosis compared with A549 cells (folate receptor deficient cell line). Folate-PEG-g-TMC shows promise for intracellular transport of negatively charged therapeutic proteins into folate receptor over-expressing tumor cells.

  12. Long-term exposure to IL-1beta enhances Toll-IL-1 receptor-mediated inflammatory signaling in murine airway hyperresponsiveness

    DEFF Research Database (Denmark)

    Zhang, Yaping; Xu, Cang-Bao; Cardell, Lars-Olaf

    2009-01-01

    Toll-interleukin-1 (Toll-IL-1) receptor signaling may play a key role in the development of airway hyperreactivity (AHR) and chronic airway inflammatory diseases such as asthma. Previously, we have demonstrated that pro-inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin......RNA expression following IL-1beta treatment. Immunohistochemistry confirmed that protein expression for CD14, RP105, MCP-1 and phosphorylated IkappaB-alpha were increased in both the airway epithelial and smooth muscle cells. In order to link the activation of Toll-IL-1 receptor-mediated inflammatory signal......-1beta (IL-1beta), induce AHR. However, the underlying intracellular signaling mechanisms that lead to AHR remain elusive. In order to see if the Toll-IL-1 receptor-mediated inflammatory signal pathways are involved in the development of AHR, the present study was designed to use a real-time PCR...

  13. Optogenetic evocation of field inhibitory postsynaptic potentials in hippocampal slices: a simple and reliable approach for studying pharmacological effects on GABAA and GABAB receptor-mediated neurotransmission

    OpenAIRE

    Dine, Julien; Kühne, Claudia; Deussing, Jan M.; Eder, Matthias

    2014-01-01

    The GABAergic system is the main source of inhibition in the mammalian brain. Consequently, much effort is still made to develop new modulators of GABAergic synaptic transmission. In contrast to glutamatergic postsynaptic potentials (PSPs), accurate monitoring of GABA receptor-mediated PSPs (GABAR-PSPs) and their pharmacological modulation in brain tissue invariably requires the use of intracellular recording techniques. However, these techniques are expensive, time- and labor-consuming, and,...

  14. Optogenetic Evocation of Field Inhibitory Postsynaptic Potentials in Hippocampal Slices: A Simple and Reliable Approach for Studying Pharmacological Effects on GABAA and GABAB Receptor-Mediated Neurotransmission

    OpenAIRE

    Julien eDine; Claudia eKühne; Deussing, Jan M.; Matthias eEder

    2014-01-01

    The GABAergic system is the main source of inhibition in the mammalian brain. Consequently, much effort is still made to develop new modulators of GABAergic synaptic transmission. In contrast to glutamatergic postsynaptic potentials (PSPs), accurate monitoring of GABA receptor-mediated PSPs (GABAR-PSPs) and their pharmacological modulation in brain tissue invariably requires the use of intracellular recording techniques. However, these techniques are expensive, time- and labor-consuming, and,...

  15. Different pools of glutamate receptors mediate sensitivity to ambient glutamate in the cochlear nucleus.

    Science.gov (United States)

    Yang, Yang; Xu-Friedman, Matthew A

    2015-06-01

    Ambient glutamate plays an important role in pathological conditions, such as stroke, but its role during normal activity is not clear. In addition, it is not clear how ambient glutamate acts on glutamate receptors with varying affinities or subcellular localizations. To address this, we studied "endbulb of Held" synapses, which are formed by auditory nerve fibers onto bushy cells (BCs) in the anteroventral cochlear nucleus. When ambient glutamate was increased by applying the glutamate reuptake inhibitor TFB-TBOA, BCs depolarized as a result of activation of N-methyl-D-aspartate receptors (NMDARs) and group I metabotropic glutamate receptors (mGluRs). Application of antagonists against NMDARs (in 0 Mg(2+)) or mGluRs caused hyperpolarization, indicating that these receptors were bound by a tonic source of glutamate. AMPA receptors did not show these effects, consistent with their lower glutamate affinity. We also evaluated the subcellular localization of the receptors activated by ambient glutamate. The mGluRs were not activated by synaptic stimulation and thus appear to be exclusively extrasynaptic. By contrast, NMDARs in both synaptic and extrasynaptic compartments were activated by ambient glutamate, as shown using the use-dependent antagonist MK-801. Levels of ambient glutamate appeared to be regulated in a spike-independent manner, and glia likely play a major role. These low levels of ambient glutamate likely have functional consequences, as even low concentrations of TBOA caused significant increases in BC spiking following synaptic stimulation. These results indicate that normal resting potential appears to be poised in the region of maximal sensitivity to small changes in ambient glutamate. PMID:25855696

  16. Molecular and Biochemical Effects of a Kola Nut Extract on Androgen Receptor-Mediated Pathways

    International Nuclear Information System (INIS)

    The low incidence of prostate cancer in Asians has been attributed to chemo preventative properties of certain chemicals found in their diet. This study characterized the androgenic and chemo preventative properties of the Jamaican bush tea Bizzy using androgen receptor positive and negative cell lines. Exposure of prostate cells to Biz-2 resulted in a growth inhibition (GI50) of 15 ppm in LNCaP cells and 3.6 ppm in DU145 cells. Biz-2 elicited a 2-fold increase in the mRNA of the anti-apoptotic gene Bcl2, with a 10-fold increase in that of the pro apoptotic gene Bax. We observed a 2.4- to 7.5-fold change in apoptotic cells in both cell lines. Biz-2 at 10 ppm elicited a time- and dose-dependent stimulation of both the protein and mRNA levels of several androgen-regulated genes. Biz-2 caused a 36% decrease in PSA secretion and a significant increase in PSA mRNA. The relative binding affinity (IC50) of Biz-2 for AR was 2- to 5-fold lower than that of the synthetic androgen R1881. Biz-2 was found to be a specific ligand for the AR in that the natural ligand, DHT, and the anti-androgen, flutamide, displaced Biz-2 bound to AR and inhibited Biz-2-induced transcription and PSA secretion. This study provided evidence that Biz-2 extract possesses the ability to modulate prostate cancer cell biology in an AR-dependent manner.

  17. CB1 receptor mediates the effects of glucocorticoids on AMPK activity in the hypothalamus.

    Science.gov (United States)

    Scerif, Miski; Füzesi, Tamás; Thomas, Julia D; Kola, Blerina; Grossman, Ashley B; Fekete, Csaba; Korbonits, Márta

    2013-10-01

    AMP-activated protein kinase (AMPK), a regulator of cellular and systemic energy homeostasis, can be influenced by several hormones. Tissue-specific alteration of AMPK activity by glucocorticoids may explain the increase in appetite, the accumulation of lipids in adipose tissues, and the detrimental cardiac effects of Cushing's syndrome. Endocannabinoids are known to mediate the effects of various hormones and to influence AMPK activity. Cannabinoids have central orexigenic and direct peripheral metabolic effects via the cannabinoid receptor type 1 (CB1). In our preliminary experiments, WT mice received implants of a corticosterone-containing pellet to establish a mouse model of Cushing's syndrome. Subsequently, WT and Cb1 (Cnr1)-knockout (CB1-KO) littermates were treated with corticosterone and AMPK activity in the hypothalamus, various adipose tissues, liver and cardiac tissue was measured. Corticosterone-treated CB1-KO mice showed a lack of weight gain and of increase in hypothalamic and hepatic AMPK activity. In adipose tissues, baseline AMPK activity was higher in CB1-KO mice, but a glucocorticoid-induced drop was observed, similar to that observed in WT mice. Cardiac AMPK levels were reduced in CB1-KO mice, but while WT mice showed significantly reduced AMPK activity following glucocorticoid treatment, CB1-KO mice showed a paradoxical increase. Our findings indicate the importance of the CB1 receptor in the central orexigenic effect of glucocorticoid-induced activation of hypothalamic AMPK activity. In the periphery adipose tissues, changes may occur independently of the CB1 receptor, but the receptor appears to alter the responsiveness of the liver and myocardial tissues to glucocorticoids. In conclusion, our data suggest that an intact cannabinoid pathway is required for the full metabolic effects of chronic glucocorticoid excess.

  18. Adolescent chronic mild stress alters hippocampal CB1 receptor-mediated excitatory neurotransmission and plasticity.

    Science.gov (United States)

    Reich, C G; Mihalik, G R; Iskander, A N; Seckler, J C; Weiss, M S

    2013-12-01

    Endocannabinoids (eCBs) are involved in the stress response and alterations in eCB signaling may contribute to the etiology of mood disorders. Exposure to chronic mild stress (CMS), a model of depression, produces downregulation of the cannabinoid 1 (CB1) receptor in the hippocampus of male rats. However, it is unknown how this stress-induced change in CB1 levels affects eCB-mediated neurotransmission. In vitro, field potential recordings from CMS-exposed (21-days) rats were performed to assess the effects of stress on eCB-regulated glutamatergic neurotransmission in/on hippocampal area CA1. We observed that application of the CB1 agonist, WIN 55,212-5 (1 μM), in stress animals resulted in a ∼135% increase in excitatory neurotransmission, whereas CB1 activation in non-stress animals leads to a ∼30% decrease. However, during blockade of GABA(A) neurotransmission with picrotoxin, CB1 activation yielded a ∼35% decrease in stress animals. These findings indicate that CMS does not directly affect glutamatergic neurotransmission. Rather, CMS sensitizes CB1 function on GABAergic terminals, leading to less inhibition and an increase in excitatory neurotransmission. This finding is reinforced in that induction of weak long-term-potentiation (LTP) is enhanced in CMS-exposed animals compared to controls and this enhancement is CB1-dependent. Lastly, we observed that the LTP-blocking property of WIN 55,212-5 shifts from being glutamate-dependent in non-stress animals to being GABA-dependent in stress animals. These results effectively demonstrate that CMS significantly alters hippocampal eCB-mediated neurotransmission and synaptic plasticity.

  19. Adiponectin increases secretion of rat submandibular gland via adiponectin receptors-mediated AMPK signaling.

    Directory of Open Access Journals (Sweden)

    Chong Ding

    Full Text Available Adiponectin and adiponectin receptors (AdipoR1/2 are expressed in various tissues and are involved in the regulation of multiple functions such as energy metabolism and inflammatory responses. However, the effect of adiponectin and AdipoRs in submandibular glands has not been fully evaluated. In the present study, we found that mRNA and protein of both adiponectin and AdipoR1/2 were expressed in rat submandibular glands and in the SMG-C6 cell line, as evidenced by RT-PCR and Western blot analysis. Immunofluorescence staining showed that adiponectin was diffused in the cytoplasm, while AdipoR1/2 was concentrated in the membrane of acinar cells. Saliva flow was significantly increased by full length adiponectin (fAd or globular adiponectin (gAd perfusion in isolated rat submandibular glands. 5-Aminoimidazole-4-carboxamide-1-4-ribofuranoside (AICAR, an adenosine monophosphate activated protein kinase (AMPK activator, also increased saliva secretion. fAd, gAd, and AICAR all increased the average width of apical tight junctions in perfused submandibular glands, and decreased transepithelial electrical resistance (TER in SMG-C6 cells, suggesting that adiponectin promoted secretion by modulating paracellular permeability. fAd and gAd increased p-AMPK levels, while AraA, an AMPK antagonist, abolished fAd- and gAd-induced changes in secretion, tight junction ultrastructure, and TER. Moreover, both AdipoR1 and AdipoR2 were required for fAd- or gAd-induced p-AMPK and TER responses, suggesting from their inhibition following AdipoR1 or AdipoR2 knockdown, and co-knockdown of AdipoRs by RNA interference. Our results suggest that adiponectin functions as a promoter of salivary secretion in rat submandibular glands via activation of AdipoRs, AMPK, and paracellular permeability.

  20. Histamine H(3 receptor-mediated signaling protects mice from cerebral malaria.

    Directory of Open Access Journals (Sweden)

    Walid Beghdadi

    Full Text Available BACKGROUND: Histamine is a biogenic amine that has been shown to contribute to several pathological conditions, such as allergic conditions, experimental encephalomyelitis, and malaria. In humans, as well as in murine models of malaria, increased plasma levels of histamine are associated with severity of infection. We reported recently that histamine plays a critical role in the pathogenesis of experimental cerebral malaria (CM in mice infected with Plasmodium berghei ANKA. Histamine exerts its biological effects through four different receptors designated H1R, H2R, H3R, and H4R. PRINCIPAL FINDINGS: In the present work, we explored the role of histamine signaling via the histamine H3 receptor (H3R in the pathogenesis of murine CM. We observed that the lack of H3R expression (H3R(-/- mice accelerates the onset of CM and this was correlated with enhanced brain pathology and earlier and more pronounced loss of blood brain barrier integrity than in wild type mice. Additionally tele-methylhistamine, the major histamine metabolite in the brain, that was initially present at a higher level in the brain of H3R(-/- mice was depleted more quickly post-infection in H3R(-/- mice as compared to wild-type counterparts. CONCLUSIONS: Our data suggest that histamine regulation through the H3R in the brain suppresses the development of CM. Thus modulating histamine signaling in the central nervous system, in combination with standard therapies, may represent a novel strategy to reduce the risk of progression to cerebral malaria.

  1. Nicotinic acetylcholine receptor-mediated calcium signaling in the nervous system

    Institute of Scientific and Technical Information of China (English)

    Jian-xin SHEN; Jerrel L YAKEL

    2009-01-01

    Based on the composition of the five subunits forming functional neuronal nicotinic acetylcholine receptors (nAChRs), they are grouped into either heteromeric (comprising both α and β subunits) or homomeric (comprising only α subunits) recep-tors. The nAChRs are known to be differentially permeable to calcium ions, with the α7 nAChR subtype having one of the highest permeabilities to calcium. Calcium influx through nAChRs, particularly through the α-bungarotoxin-sensitive α7-containing nAChRs, is a very efficient way to raise cytoplasmic calcium levels. The activation of nAChRs can mediate three types of cytoplasmic calcium signals: (1) direct calcium influx through the nAChRs, (2) indirect calcium influx through voltage-dependent calcium channels (VDCCs) which are activated by the nAChR-mediated depolarization, and (3) calcium-induced calcium release (CICR) (triggered by the first two sources) from the endoplasmic reticulum (ER) through the ryanodine receptors and inositol (1,4,5)-triphosphate receptors (IP3Rs). Downstream signaling events mediated by nAChR-mediated calcium responses can be grouped into instantaneous effects (such as neurotransmitter release, which can occur in milliseconds after nAChR activation), short-term effects (such as the recovery of nAChR desensitization through cellular signaling cascades), and long-term effects (such as neuroprotection via gene expression). In addition, nAChR activity can be regulated by cytoplasmic calcium levels, suggesting a complex reciprocal relationship. Further advances in imaging techniques, animal models, and more potent and subtype-selective ligands for neuronal nAChRs would help in understand-ing the neuronal nAChR-mediated calcium signaling, and lead to the development of improved therapeutic treatments.

  2. Molecular and Biochemical Effects of a Kola Nut Extract on Androgen Receptor-Mediated Pathways

    Directory of Open Access Journals (Sweden)

    Rajasree Solipuram

    2009-01-01

    Full Text Available The low incidence of prostate cancer in Asians has been attributed to chemopreventative properties of certain chemicals found in their diet. This study characterized the androgenic and chemopreventative properties of the Jamaican bush tea “Bizzy,” using androgen receptor positive and negative cell lines. Exposure of prostate cells to Biz-2 resulted in a growth inhibition (GI50 of 15 ppm in LNCaP cells and 3.6 ppm in DU145 cells. Biz-2 elicited a 2-fold increase in the mRNA of the anti-apoptotic gene Bcl2, with a 10-fold increase in that of the proapoptotic gene Bax. We observed a 2.4- to 7.5-fold change in apoptotic cells in both cell lines. Biz-2 at 10 ppm elicited a time- and dose-dependent stimulation of both the protein and mRNA levels of several androgen-regulated genes. Biz-2 caused a 36% decrease in PSA secretion and a significant increase in PSA mRNA. The relative binding affinity (IC50 of Biz-2 for AR was 2- to 5-fold lower than that of the synthetic androgen R1881. Biz-2 was found to be a specific ligand for the AR in that the natural ligand, DHT, and the anti-androgen, flutamide, displaced Biz-2 bound to AR and inhibited Biz-2-induced transcription and PSA secretion. This study provided evidence that Biz-2 extract possesses the ability to modulate prostate cancer cell biology in an AR-dependent manner.

  3. Role of receptor-mediated endocytosis, endosomal acidification and cathepsin D in cholera toxin cytotoxicity.

    Science.gov (United States)

    El Hage, Tatiana; Merlen, Clémence; Fabrega, Sylvie; Authier, François

    2007-05-01

    response to cholera toxin. Thus, in hepatic cells, a unique endocytic pathway was revealed following cholera toxin administration, with regulation specificity most probably occurring at the locus of the endosome and implicating endosomal proteases, such as cathepsin D, as well as organelle acidification. PMID:17451437

  4. Role of receptor-mediated endocytosis, endosomal acidification and cathepsin D in cholera toxin cytotoxicity.

    Science.gov (United States)

    El Hage, Tatiana; Merlen, Clémence; Fabrega, Sylvie; Authier, François

    2007-05-01

    response to cholera toxin. Thus, in hepatic cells, a unique endocytic pathway was revealed following cholera toxin administration, with regulation specificity most probably occurring at the locus of the endosome and implicating endosomal proteases, such as cathepsin D, as well as organelle acidification.

  5. Luteinizing hormone-releasing hormone receptor-mediated delivery of mitoxantrone using LHRH analogs modified with PEGylated liposomes

    Directory of Open Access Journals (Sweden)

    Yingna He

    2010-09-01

    Full Text Available Yingna He, Linhua Zhang, Cunxian SongKey Laboratory of Biomedical Material of Tianjin, Institute of Biomedical Engineering, Peking Union Medical College and Chinese Academy of Medical Sciences, Tianjin, ChinaAbstract: A sterically stabilized, mitoxantrone-loaded liposome, tailored to target luteinizing hormone-releasing hormone (LHRH receptor overexpressing cells, was developed to promote the efficiency of intracellular delivery of mitoxantrone through receptor-mediated endocytosis. Liposomes were prepared by lipid film hydration and an ultrasound dispersion process. Thiolated gonadorelin with affinity for the LHRH receptor was chemically coupled to N-[(3-maleimide-1-oxopropyl aminopropyl polyethylene glycol-carbamyl] distearoyl-l-phosphatidyl-ethanolamine via a thioether bond and subsequently inserted into polyethylene glycol-grafted liposomes. The liposome was characterized in terms of its size, ligand density, drug loading, and leakage properties. The targeting nature and antitumor effects of the liposomes were evaluated in vitro using cultured MCF-7 breast cancer cells. A protein assay of ligand coupling to the liposomal surface indicated that more than 60% of the LHRH peptides were inserted into the liposome bilayer. Up to 1.0 mg/mL of stable liposomal mitoxantrone loading was achieved, with approximately 98% of this being entrapped within the liposomes. In vitro cell culture studies revealed that the gonadorelin-modified liposomes bound to their target cells had significantly higher affinity and better antitumor efficiency than generic drug-loaded liposomes. These events were presumed to occur through specific interactions of the LHRH with its cognate receptors on the cell surface. It was concluded that the targeting properties of the delivery system would potentially improve the therapeutic benefits of mitoxantrone, as compared with nontargeted liposomes.Keywords: mitoxantrone, liposome, luteinizing hormone-releasing hormone receptor

  6. Receptor-mediated hepatic uptake of M6P-BSA-conjugated triplex-forming oligonucleotides in rats.

    Science.gov (United States)

    Ye, Zhaoyang; Cheng, Kun; Guntaka, Ramareddy V; Mahato, Ram I

    2006-01-01

    Excessive production of extracellular matrix, predominantly type I collagen, results in liver fibrosis. Earlier we synthesized mannose 6-phosphate-bovine serum albumin (M6P-BSA) and conjugated to the type I collagen specific triplex-forming oligonucleotide (TFO) for its enhanced delivery to hepatic stellate cells (HSCs), which is the principal liver fibrogenic cell. In this report, we demonstrate a time-dependent cellular uptake of M6P-BSA-33P-TFO by HSC-T6 cells. Both cellular uptake and nuclear deposition of M6P-BSA-33P-TFO were significantly higher than those of 33P-TFO, leading to enhanced inhibition of type I collagen transcription. Following systemic administration into rats, hepatic accumulation of M6P-BSA-33P-TFO increased from 55% to 68% with the number of M6P per BSA from 14 to 27. Unlike 33P-TFO, there was no significant decrease in the hepatic uptake of (M6P)20-BSA-33P-TFO in fibrotic rats. Prior administration of excess M6P-BSA decreased the hepatic uptake of (M6P)20-BSA-33P-TFO from 66% to 40% in normal rats, and from 60% to 15% in fibrotic rats, suggesting M6P/insulin-like growth factor II (M6P/IGF II) receptor-mediated endocytosis of M6P-BSA-33P-TFO by HSCs. Almost 82% of the total liver uptake in fibrotic rats was contributed by HSCs. In conclusion, by conjugation with M6P-BSA, the TFO could be potentially used for the treatment of liver fibrosis.

  7. Urotensin Ⅱ inhibits electrical activity of hippocampal CA1 neurons by potentiating the GABAA receptor-mediated Cl- current

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective To examine the effects of urotensin Ⅱ (UII) on the discharges of neurons in CA1 area of hippocampal slices by using extracellular recording technique. Results① In response to the application of UII (0.3, 3.0,30.0, 300.0 nmol/L, n =77) into the perfusate for 2 min, the spontaneous discharge rates (SDR) of 63/77 (81.8%) neurons were significantly decreased in a dose-dependent manner. ②Pretreatment with bicuculline( BIC, 100 μmol/L) , a specific GABAA receptor antagonist, led to a marked increase in the SDR of 6/7 (85.71% ) neurons in an epileptiform pattern. The increased discharges were not significantly changed after UII (30.0 nmol/L) was applied into the perfusate for 2 min. ③ Pretreatment with picrotoxin (PIC, 50 μmol/L) , a selective blocker of Cl- channel, led to an increase in the SDR of all 8/8 (100%) neurons. The increased discharges were not influenced by the UII (30.0 nmol/L) applied.④Application of nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 50 μmol/L) into the perfusate for 2 min also significantly augmented the SDR of 14/16 (87.5%) neurons , then UII (30.0 nmol/L) applied into the perfusate reduced the increased the SDR of all 14/14 ( 100% ) neurons. Conclusion These results suggest that UII may decrease neuronal activity by potentiating GABAA receptor-mediated Cl- current in hippocampal CA1 neurons, and involved with the mediation of nitric oxide.

  8. Modulation of the input-output function by GABAA receptor-mediated currents in rat oculomotor nucleus motoneurons.

    Science.gov (United States)

    Torres-Torrelo, Julio; Torres, Blas; Carrascal, Livia

    2014-11-15

    The neuronal input-output function depends on recruitment threshold and gain of the firing frequency-current (f-I) relationship. These two parameters are positively correlated in ocular motoneurons (MNs) recorded in alert preparation and inhibitory inputs could contribute to this correlation. Phasic inhibition mediated by γ-amino butyric acid (GABA) occurs when a high concentration of GABA at the synaptic cleft activates postsynaptic GABAA receptors, allowing neuronal information transfer. In some neuronal populations, low concentrations of GABA activate non-synaptic GABAA receptors and generate a tonic inhibition, which modulates cell excitability. This study determined how ambient GABA concentrations modulate the input-output relationship of rat oculomotor nucleus MNs. Superfusion of brain slices with GABA (100 μm) produced a GABAA receptor-mediated current that reduced the input resistance, increased the recruitment threshold and shifted the f-I relationship rightward without any change in gain. These modifications did not depend on MN size. In absence of exogenous GABA, gabazine (20 μm; antagonist of GABAA receptors) abolished spontaneous inhibitory postsynaptic currents and revealed a tonic current in MNs. Gabazine increased input resistance and decreased recruitment threshold mainly in larger MNs. The f-I relationship shifted to the left, without any change in gain. Gabazine effects were chiefly due to MN tonic inhibition because tonic current amplitude was five-fold greater than phasic. This study demonstrates a tonic inhibition in ocular MNs that modulates cell excitability depending on cell size. We suggest that GABAA tonic inhibition acting concurrently with glutamate receptors activation could reproduce the positive covariation between threshold and gain reported in alert preparation.

  9. Hypersensitivity to thromboxane receptor mediated cerebral vasomotion and CBF oscillations during acute NO-deficiency in rats.

    Directory of Open Access Journals (Sweden)

    Béla Horváth

    Full Text Available BACKGROUND: Low frequency (4-12 cpm spontaneous fluctuations of the cerebrovascular tone (vasomotion and oscillations of the cerebral blood flow (CBF have been reported in diseases associated with endothelial dysfunction. Since endothelium-derived nitric oxide (NO suppresses constitutively the release and vascular effects of thromboxane A(2 (TXA(2, NO-deficiency is often associated with activation of thromboxane receptors (TP. In the present study we hypothesized that in the absence of NO, overactivation of the TP-receptor mediated cerebrovascular signaling pathway contributes to the development of vasomotion and CBF oscillations. METHODOLOGY/PRINCIPAL FINDINGS: Effects of pharmacological modulation of TP-receptor activation and its downstream signaling pathway have been investigated on CBF oscillations (measured by laser-Doppler flowmetry in anesthetized rats and vasomotion (measured by isometric tension recording in isolated rat middle cerebral arteries, MCAs both under physiological conditions and after acute inhibition of NO synthesis. Administration of the TP-receptor agonist U-46619 (1 µg/kg i.v. to control animals failed to induce any changes of the systemic or cerebral circulatory parameters. Inhibition of the NO synthesis by nitro-L-arginine methyl ester (L-NAME, 100 mg/kg i.v. resulted in increased mean arterial blood pressure and a decreased CBF accompanied by appearance of CBF-oscillations with a dominant frequency of 148±2 mHz. U-46619 significantly augmented the CBF-oscillations induced by L-NAME while inhibition of endogenous TXA(2 synthesis by ozagrel (10 mg/kg i.v. attenuated it. In isolated MCAs U-46619 in a concentration of 100 nM, which induced weak and stable contraction under physiological conditions, evoked sustained vasomotion in the absence of NO, which effect could be completely reversed by inhibition of Rho-kinase by 10 µM Y-27632. CONCLUSION/SIGNIFICANCE: These results suggest that hypersensitivity of the TP

  10. Development of drug loaded nanoparticles for tumor targeting. Part 2: Enhancement of tumor penetration through receptor mediated transcytosis in 3D tumor models

    Science.gov (United States)

    El-Dakdouki, Mohammad H.; Puré, Ellen; Huang, Xuefei

    2013-04-01

    We report that receptor mediated transcytosis can be utilized to facilitate tumor penetration by drug loaded nanoparticles (NPs). We synthesized hyaluronan (HA) coated silica nanoparticles (SNPs) containing a highly fluorescent core to target CD44 expressed on the cancer cell surface. Although prior studies have primarily focused on CD44 mediated endocytosis to facilitate cellular uptake of HA-NPs by cancer cells, we discovered that, once internalized, the HA-SNPs could be transported out of the cells with their cargo. The exported NPs could be taken up by neighboring cells. This enabled the HA-SNPs to penetrate deeper inside tumors and reach a much greater number of tumor cells in 3D tumor models, presumably through tandem cycles of CD44 mediated endocytosis and exocytosis. When doxorubicin (DOX) was loaded onto the NPs, better penetration of multilayered tumor cells was observed with much improved cytotoxicities against both drug sensitive and drug resistant cancer spheroids compared to the free drug. Thus, targeting receptors such as CD44 that can readily undergo recycling between the cell surface and interior of the cells can become a useful strategy to enhance the tumor penetration potential of NPs and the efficiency of drug delivery through receptor mediated transcytosis.We report that receptor mediated transcytosis can be utilized to facilitate tumor penetration by drug loaded nanoparticles (NPs). We synthesized hyaluronan (HA) coated silica nanoparticles (SNPs) containing a highly fluorescent core to target CD44 expressed on the cancer cell surface. Although prior studies have primarily focused on CD44 mediated endocytosis to facilitate cellular uptake of HA-NPs by cancer cells, we discovered that, once internalized, the HA-SNPs could be transported out of the cells with their cargo. The exported NPs could be taken up by neighboring cells. This enabled the HA-SNPs to penetrate deeper inside tumors and reach a much greater number of tumor cells in 3D tumor

  11. The Critical Role Of VP1 In Forming The Necessary Cavities For Receptor-mediated Entry Of FMDV To The Host Cell

    OpenAIRE

    Jahanshah Ashkani; Rees, D. J. G.

    2016-01-01

    The antigenic inconsistency of the foot-and-mouth disease virus (FMDV) is very broad, such that a vaccine made from one isolate will not offer protection against infection with other isolates from the same serotype. Viral particles (VPs) or surface exposed capsid proteins, VP1–VP3, of FMDV determine both the antigenicity of the virus and its receptor-mediated entry into the host cell. Therefore, modifications of these structural proteins may alter the properties of the virus. Here we show put...

  12. Mu-Opioid (MOP) receptor mediated G-protein signaling is impaired in specific brain regions in a rat model of schizophrenia.

    Science.gov (United States)

    Szűcs, Edina; Büki, Alexandra; Kékesi, Gabriella; Horváth, Gyöngyi; Benyhe, Sándor

    2016-04-21

    Schizophrenia is a complex mental health disorder. Clinical reports suggest that many patients with schizophrenia are less sensitive to pain than other individuals. Animal models do not interpret schizophrenia completely, but they can model a number of symptoms of the disease, including decreased pain sensitivities and increased pain thresholds of various modalities. Opioid receptors and endogenous opioid peptides have a substantial role in analgesia. In this biochemical study we investigated changes in the signaling properties of the mu-opioid (MOP) receptor in different brain regions, which are involved in the pain transmission, i.e., thalamus, olfactory bulb, prefrontal cortex and hippocampus. Our goal was to compare the transmembrane signaling mediated by MOP receptors in control rats and in a recently developed rat model of schizophrenia. Regulatory G-protein activation via MOP receptors were measured in [(35)S]GTPγS binding assays in the presence of a highly selective MOP receptor peptide agonist, DAMGO. It was found that the MOP receptor mediated activation of G-proteins was substantially lower in membranes prepared from the 'schizophrenic' model rats than in control animals. The potency of DAMGO to activate MOP receptor was also decreased in all brain regions studied. Taken together in our rat model of schizophrenia, MOP receptor mediated G-proteins have a reduced stimulatory activity compared to membrane preparations taken from control animals. The observed distinct changes of opioid receptor functions in different areas of the brain do not explain the augmented nociceptive threshold described in these animals.

  13. Changes in synaptic and extrasynaptic N-methyl-D-aspartate receptor-mediated currents at early-stage epileptogenesis in adult mice

    Institute of Scientific and Technical Information of China (English)

    Juegang Ju; Sheng-tian Li

    2011-01-01

    Previous reports have shown that N-methyl-D-aspartate (NMDA) receptors are extensively involved in epilepsy genesis and recurrence.Recent studies have shown that synaptic and extrasynaptic NMDA receptors play different, or even opposing, roles in various signaling pathways, including synaptic plasticity and neuronal death.The present study analyzed changes in synaptic and extrasynaptic NMDA receptor-mediated currents during epilepsy onset.Mouse models of lithium chloride pilocarpine-induced epilepsy were established, and hippocampal slices were prepared at 24 hours after the onset of status epilepticus.Synaptic and extrasynaptic NMDA receptor-mediated excitatory post-synaptic currents (NMDA-EPSCs) were recorded in CA1 pyramidal neurons by whole-cell patch clamp technique.Results demonstrated no significant difference in rise and delay time of synaptic NMDA-EPSCs compared with normal neurons.Peak amplitude, area-to-peak ratio,and rising time of extrasynaptic NMDA-EPSCs remained unchanged, but decay of extrasynaptic NMDA-EPSCs was faster than that of normal neurons.These results suggest that extrasynaptic NMDA receptors play a role in epileptogenesis.

  14. Mu-Opioid (MOP) receptor mediated G-protein signaling is impaired in specific brain regions in a rat model of schizophrenia.

    Science.gov (United States)

    Szűcs, Edina; Büki, Alexandra; Kékesi, Gabriella; Horváth, Gyöngyi; Benyhe, Sándor

    2016-04-21

    Schizophrenia is a complex mental health disorder. Clinical reports suggest that many patients with schizophrenia are less sensitive to pain than other individuals. Animal models do not interpret schizophrenia completely, but they can model a number of symptoms of the disease, including decreased pain sensitivities and increased pain thresholds of various modalities. Opioid receptors and endogenous opioid peptides have a substantial role in analgesia. In this biochemical study we investigated changes in the signaling properties of the mu-opioid (MOP) receptor in different brain regions, which are involved in the pain transmission, i.e., thalamus, olfactory bulb, prefrontal cortex and hippocampus. Our goal was to compare the transmembrane signaling mediated by MOP receptors in control rats and in a recently developed rat model of schizophrenia. Regulatory G-protein activation via MOP receptors were measured in [(35)S]GTPγS binding assays in the presence of a highly selective MOP receptor peptide agonist, DAMGO. It was found that the MOP receptor mediated activation of G-proteins was substantially lower in membranes prepared from the 'schizophrenic' model rats than in control animals. The potency of DAMGO to activate MOP receptor was also decreased in all brain regions studied. Taken together in our rat model of schizophrenia, MOP receptor mediated G-proteins have a reduced stimulatory activity compared to membrane preparations taken from control animals. The observed distinct changes of opioid receptor functions in different areas of the brain do not explain the augmented nociceptive threshold described in these animals. PMID:26946106

  15. The Critical Role Of VP1 In Forming The Necessary Cavities For Receptor-mediated Entry Of FMDV To The Host Cell

    Science.gov (United States)

    Ashkani, Jahanshah; Rees, D. J. G.

    2016-01-01

    The antigenic inconsistency of the foot-and-mouth disease virus (FMDV) is very broad, such that a vaccine made from one isolate will not offer protection against infection with other isolates from the same serotype. Viral particles (VPs) or surface exposed capsid proteins, VP1–VP3, of FMDV determine both the antigenicity of the virus and its receptor-mediated entry into the host cell. Therefore, modifications of these structural proteins may alter the properties of the virus. Here we show putative cavities on the FMDV-SAT1 (FMDV Southern African Territories1) capsid as possible binding sites for the receptor-mediated viral entry into the host cell. We identified three possible cavities on the FMDV capsid surface, from which the largest one (C2) is shaped in the contact regions of VP1–VP3. Our results demonstrate the significance of VP1, in the formation of FMDV-SAT1 surface cavities, which is the main component in all the identified cavities. Our findings can have profound implications in the protein engineering of FMDV in the contact region of VP1–VP3 found to be embedded in several cavities. Such information is of great significance in the context of vaccine design, as it provides the ground for future improvement of synthetic vaccines to control FMD caused by FMDV-SAT1 serotypes. PMID:27249937

  16. The Critical Role Of VP1 In Forming The Necessary Cavities For Receptor-mediated Entry Of FMDV To The Host Cell.

    Science.gov (United States)

    Ashkani, Jahanshah; Rees, D J G

    2016-01-01

    The antigenic inconsistency of the foot-and-mouth disease virus (FMDV) is very broad, such that a vaccine made from one isolate will not offer protection against infection with other isolates from the same serotype. Viral particles (VPs) or surface exposed capsid proteins, VP1-VP3, of FMDV determine both the antigenicity of the virus and its receptor-mediated entry into the host cell. Therefore, modifications of these structural proteins may alter the properties of the virus. Here we show putative cavities on the FMDV-SAT1 (FMDV Southern African Territories1) capsid as possible binding sites for the receptor-mediated viral entry into the host cell. We identified three possible cavities on the FMDV capsid surface, from which the largest one (C2) is shaped in the contact regions of VP1-VP3. Our results demonstrate the significance of VP1, in the formation of FMDV-SAT1 surface cavities, which is the main component in all the identified cavities. Our findings can have profound implications in the protein engineering of FMDV in the contact region of VP1-VP3 found to be embedded in several cavities. Such information is of great significance in the context of vaccine design, as it provides the ground for future improvement of synthetic vaccines to control FMD caused by FMDV-SAT1 serotypes. PMID:27249937

  17. Receptor-mediated delivery of all-trans-retinoic acid (ATRA) to hepatocytes from ATRA-loaded poly(N-p-vinylbenzyl-4-o-{beta}-D-galactopyranosyl-D-gluconamide) nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Seog-Jin [School of Agricultural Biotechnology, Seoul National University, Seoul 151-742 (Korea, Republic of) ; Moon, Hyun-Seuk [School of Agricultural Biotechnology, Seoul National University, Seoul 151-742 (Korea, Republic of) ; Guo, Ding-Ding [School of Agricultural Biotechnology, Seoul National University, Seoul 151-742 (Korea, Republic of) ; Kim, Sang-Heon [Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of) ; Akaike, Toshihiro [Department of Biomolecular Engineering, Tokyo Institute of Technology, Yokohama 226-8501 (Japan); Cho, Chong-Su [School of Agricultural Biotechnology, Seoul National University, Seoul 151-742 (Korea, Republic of) ]. E-mail: chocs@plaza.snu.ac.kr

    2006-01-15

    All-trans-retinoic acid (ATRA) plays a role in regulating CYP26 gene expression in hepatocytes. Poly(N-p-vinylbenzyl-4-o-{beta}-D-galactopyranosyl-D-gluconamide) (PVLA) nanoparticles have been used as hepatocyte-specific targeting candidates. The objective of this study was to investigate receptor-mediated delivery of ATRA using PVLA nanoparticles. ATRA-loaded PVLA nanoparticles were confirmed by {sup 1}H-nuclear magnetic resonance ({sup 1}H-NMR) and powder X-ray diffraction (XRD). In the {sup 1}H-NMR study, the proton signals of ATRA disappeared in the spectrum of ATRA-loaded PVLA nanoparticles in D{sub 2}O, whereas in dimethylsulfoxide-d{sub 6}, the spectrum seemed like an addition of the respective spectrum of each of the pure components. The crystalline peaks of ATRA disappeared in the XRD pattern of ATRA-loaded PVLA nanoparticles after ATRA was loaded into PVLA nanoparticles. In the measurement of size distribution, diameter of PVLA and ATRA-loaded PVLA nanoparticles in aqueous solution was 6.9 and 61.2 nm in number average, respectively. Flow cytometric analysis showed that the internalization of FITC-PVLA nanoparticles by hepatocytes in the absence of a competitive inhibitor was larger than preincubated with galactose. In reverse transcription-polymerase chain reaction (RT-PCR) analysis, ATRA-loaded PVLA nanoparticles induced CYP26A1 gene in hepatocytes in the absence of a competitive inhibitor but not preincubated with galactose. The results indicate that the ATRA-loaded PVLA nanoparticle can induce CYP26A1 gene in aqueous phase by an asialoglycoprotein receptor (ASGPR)-mediated delivery system.

  18. Ontogeny of catecholamine and adenosine receptor-mediated cAMP signaling of embryonic red blood cells: role of cGMP-inhibited phosphodiesterase 3 and hemoglobin.

    Science.gov (United States)

    Baumann, R; Blass, C; Götz, R; Dragon, S

    1999-12-15

    We have previously shown that the cAMP signaling pathway controls major aspects of embryonic red blood cell (RBC) function in avian embryos (Glombitza et al, Am J Physiol 271:R973, 1996; and Dragon et al, Am J Physiol 271:R982, 1996) that are important for adaptation of the RBC gas transport properties to the progressive hypercapnia and hypoxia of later stages of avian embryonic development. Data about the ontogeny of receptor-mediated cAMP signaling are lacking. We have analyzed the response of primitive and definitive chick embryo RBC harvested from day 3 to 18 of development towards forskolin, beta-adrenergic, and A2 receptor agonists. The results show a strong response of immature definitive and primitive RBC to adenosine A2 and beta-adrenergic receptor agonists, which is drastically reduced in the last stage of development, coincident with the appearance of mature, transcriptionally inactive RBC. Modulation of cGMP-inhibited phosphodiesterase 3 (PDE3) has a controlling influence on cAMP accumulation in definitive RBC. Under physiological conditions, PDE3 is inhibited due to activation of soluble guanylyl cyclase (sGC). Inhibition of sGC with the specific inhibitor ODQ decreases receptor-mediated stimulation of cAMP production; this effect is reversed by the PDE3 inhibitor milrinone. sGC is acitivated by nitric oxide (NO), but we found no evidence for production of NO by erythrocyte NO-synthase. However, embryonic hemoglobin releases NO in an oxygen-linked manner that may activate guanylyl cyclase.

  19. GABAA receptor-mediated feedforward and feedback inhibition differentially modulate the gain and the neural code transformation in hippocampal CA1 pyramidal cells.

    Science.gov (United States)

    Jang, Hyun Jae; Park, Kyerl; Lee, Jaedong; Kim, Hyuncheol; Han, Kyu Hun; Kwag, Jeehyun

    2015-12-01

    Diverse variety of hippocampal interneurons exists in the CA1 area, which provides either feedforward (FF) or feedback (FB) inhibition to CA1 pyramidal cell (PC). However, how the two different inhibitory network architectures modulate the computational mode of CA1 PC is unknown. By investigating the CA3 PC rate-driven input-output function of CA1 PC using in vitro electrophysiology, in vitro-simulation of inhibitory network, and in silico computational modeling, we demonstrated for the first time that GABAA receptor-mediated FF and FB inhibition differentially modulate the gain, the spike precision, the neural code transformation and the information capacity of CA1 PC. Recruitment of FF inhibition buffered the CA1 PC spikes to theta-frequency regardless of the input frequency, abolishing the gain and making CA1 PC insensitive to its inputs. Instead, temporal variability of the CA1 PC spikes was increased, promoting the rate-to-temporal code transformation to enhance the information capacity of CA1 PC. In contrast, the recruitment of FB inhibition sub-linearly transformed the input rate to spike output rate with high gain and low spike temporal variability, promoting the rate-to-rate code transformation. These results suggest that GABAA receptor-mediated FF and FB inhibitory circuits could serve as network mechanisms for differentially modulating the gain of CA1 PC, allowing CA1 PC to switch between different computational modes using rate and temporal codes ad hoc. Such switch will allow CA1 PC to efficiently respond to spatio-temporally dynamic inputs and expand its computational capacity during different behavioral and neuromodulatory states in vivo.

  20. [Epigenetic Regulation by Androgen Receptor and Possible Function in Bone Metabolism].

    Science.gov (United States)

    Imai, Yuuki

    2016-07-01

    Epigenetic regulation underlying AR(Androgen receptor)mediated transcription is important component to understand pathophysiology of osteoporosis in men. In this commentary, it is reported recent findings related to epigenetic landscape governed by AR and its cofactors including lysine-specific demethylase 1 (LSD1), and possible implication for bone metabolism. PMID:27346313

  1. Identification of a Novel Cell Death Receptor Mediating IGFBP-3-induced Anti-tumor Effects in Breast and Prostate Cancer*

    OpenAIRE

    Ingermann, Angela R.; Yang, Yong-feng; Han, Jinfeng; Mikami, Aki; Garza, Amanda E.; Mohanraj, Lathika; Fan, Lingbo; Idowu, Michael; Ware, Joy L.; Kim, Ho-Seong; Lee, Dae-Yeol; Oh, Youngman

    2010-01-01

    Insulin-like growth factor-binding protein-3 (IGFBP-3), a major regulator of endocrine actions of IGFs, is a p53-regulated potent apoptotic factor and is significantly suppressed in a variety of cancers. Recent epidemiologic studies suggest that IGFBP-3 contributes to cancer risk protection in a variety of cancers, and a polymorphic variation of IGFBP-3 influences cancer risk, although other studies vary in their conclusions. Some antiproliferative actions of IGFBP-3 have been reported to be ...

  2. CDK11{sup p58} represses vitamin D receptor-mediated transcriptional activation through promoting its ubiquitin-proteasome degradation

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Yayun; Hong, Yi; Zong, Hongliang; Wang, Yanlin; Zou, Weiying; Yang, Junwu; Kong, Xiangfei; Yun, Xiaojing [Gene Research Center, Shanghai Medical College and Institutes of Biomedical, Shanghai 200032 (China); Gu, Jianxin, E-mail: jxgu@shmu.edu.cn [Gene Research Center, Shanghai Medical College and Institutes of Biomedical, Shanghai 200032 (China)

    2009-08-28

    Vitamin D receptor (VDR) is a member of the nuclear receptor superfamily and regulates transcription of target genes. In this study, we identified CDK11{sup p58} as a novel protein involved in the regulation of VDR. CDK11{sup p58}, a member of the large family of p34cdc2-related kinases, is associated with cell cycle progression, tumorigenesis, and apoptotic signaling. Our study demonstrated that CDK11{sup p58} interacted with VDR and repressed VDR-dependent transcriptional activation. Furthermore, overexpression of CDK11{sup p58} decreased the stability of VDR through promoting its ubiquitin-proteasome-mediated degradation. Taken together, these results suggest that CDK11{sup p58} is involved in the negative regulation of VDR.

  3. CDK11p58 represses vitamin D receptor-mediated transcriptional activation through promoting its ubiquitin-proteasome degradation

    International Nuclear Information System (INIS)

    Vitamin D receptor (VDR) is a member of the nuclear receptor superfamily and regulates transcription of target genes. In this study, we identified CDK11p58 as a novel protein involved in the regulation of VDR. CDK11p58, a member of the large family of p34cdc2-related kinases, is associated with cell cycle progression, tumorigenesis, and apoptotic signaling. Our study demonstrated that CDK11p58 interacted with VDR and repressed VDR-dependent transcriptional activation. Furthermore, overexpression of CDK11p58 decreased the stability of VDR through promoting its ubiquitin-proteasome-mediated degradation. Taken together, these results suggest that CDK11p58 is involved in the negative regulation of VDR.

  4. Investigation of the receptor-mediated endocytosis of transcobalamin/intrinsic factor-vitamin B12 complexes

    DEFF Research Database (Denmark)

    Beedholm, Rasmus; Grissom, Charles B.; Fedosov, Sergey N.;

    receptor structure. This receptor is suggested to be regulated by the vitamin B12 level in the cells, which is interesting in relation to cancer growth. The cellular endocytosis of TC- B12 complex by this unknown receptor is being investigated, using confocal microscopy. Fluorescently labeled B12 molecules...

  5. Androgen Receptor-Mediated Growth Suppression of HPr-1AR and PC3-Lenti-AR Prostate Epithelial Cells.

    Directory of Open Access Journals (Sweden)

    Young-Chae Kim

    Full Text Available The androgen receptor (AR mediates the developmental, physiologic, and pathologic effects of androgens including 5α-dihydrotestosterone (DHT. However, the mechanisms whereby AR regulates growth suppression and differentiation of luminal epithelial cells in the prostate gland and proliferation of malignant versions of these cells are not well understood, though they are central to prostate development, homeostasis, and neoplasia. Here, we identify androgen-responsive genes that restrain cell cycle progression and proliferation of human prostate epithelial cell lines (HPr-1AR and PC3-Lenti-AR, and we investigate the mechanisms through which AR regulates their expression. DHT inhibited proliferation of HPr-1AR and PC3-Lenti-AR, and cell cycle analysis revealed a prolonged G1 interval. In the cell cycle, the G1/S-phase transition is initiated by the activity of cyclin D and cyclin-dependent kinase (CDK complexes, which relieve growth suppression. In HPr-1AR, cyclin D1/2 and CDK4/6 mRNAs were androgen-repressed, whereas CDK inhibitor, CDKN1A, mRNA was androgen-induced. The regulation of these transcripts was AR-dependent, and involved multiple mechanisms. Similar AR-mediated down-regulation of CDK4/6 mRNAs and up-regulation of CDKN1A mRNA occurred in PC3-Lenti-AR. Further, CDK4/6 overexpression suppressed DHT-inhibited cell cycle progression and proliferation of HPr-1AR and PC3-Lenti-AR, whereas CDKN1A overexpression induced cell cycle arrest. We therefore propose that AR-mediated growth suppression of HPr-1AR involves cyclin D1 mRNA decay, transcriptional repression of cyclin D2 and CDK4/6, and transcriptional activation of CDKN1A, which serve to decrease CDK4/6 activity. AR-mediated inhibition of PC3-Lenti-AR proliferation occurs through a similar mechanism, albeit without down-regulation of cyclin D. Our findings provide insight into AR-mediated regulation of prostate epithelial cell proliferation.

  6. Activation and Regulation of Cellular Eicosanoid Biosynthesis

    Directory of Open Access Journals (Sweden)

    Thomas G. Brock

    2007-01-01

    Full Text Available There is a growing appreciation for the wide variety of physiological responses that are regulated by lipid messengers. One particular group of lipid messengers, the eicosanoids, plays a central role in regulating immune and inflammatory responses in a receptor-mediated fashion. These mediators are related in that they are all derived from one polyunsaturated fatty acid, arachidonic acid. However, the various eicosanoids are synthesized by a wide variety of cell types by distinct enzymatic pathways, and have diverse roles in immunity and inflammation. In this review, the major pathways involved in the synthesis of eicosanoids, as well as key points of regulation, are presented.

  7. LncRNA HOTAIR Enhances the Androgen-Receptor-Mediated Transcriptional Program and Drives Castration-Resistant Prostate Cancer

    OpenAIRE

    Ali Zhang; Jonathan C. Zhao; Jung Kim; Ka-wing Fong; Yeqing Angela Yang; Debabrata Chakravarti; Yin-Yuan Mo; Jindan Yu

    2015-01-01

    SUMMARY Understanding the mechanisms of androgen receptor (AR) activation in the milieu of low androgen is critical to effective treatment of castration-resistant prostate cancer (CRPC). Here, we report HOTAIR as an androgen-repressed lncRNA, and, as such, it is markedly upregulated following androgen deprivation therapies and in CRPC. We further demonstrate a distinct mode of lncRNA-mediated gene regulation, wherein HOTAIR binds to the AR protein to block its interaction with the E3 ubiquiti...

  8. Degradation of Epidermal Growth Factor Receptor Mediates Dasatinib-Induced Apoptosis in Head and Neck Squamous Cell Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Yu-Chin Lin

    2012-06-01

    Full Text Available Epidermal growth factor receptor (EGFR is an important oncoprotein that promotes cell growth and proliferation. Dasatinib, a bcr-abl inhibitor, has been approved clinically for the treatment of chronic myeloid leukemia and demonstrated to be effective against solid tumors in vitro through Src inhibition. Here, we disclose that EGFR degradation mediated dasatinib-induced apoptosis in head and neck squamous cell carcinoma (HNSCC cells. HNSCC cells, including Ca9-22, FaDu, HSC3, SAS, SCC-25, and UMSCC1, were treated with dasatinib, and cell viability, apoptosis, and underlying signal transduction were evaluated. Dasatinib exhibited differential sensitivities against HNSCC cells. Growth inhibition and apoptosis were correlated with its inhibition on Akt, Erk, and Bcl-2, irrespective of Src inhibition. Accordingly, we found that down-regulation of EGFR was a determinant of dasatinib sensitivity. Lysosome inhibitor reversed dasatinib-induced EGFR down-regulation, and c-cbl activity was increased by dasatinib, indicating that dasatinib-induced EGFR down-regulation might be through c-cbl-mediated lysosome degradation. Increased EGFR activation by ligand administration rescued cells from dasatinib-induced apoptosis, whereas inhibition of EGFR enhanced its apoptotic effect. Estrogen receptor α (ERα was demonstrated to play a role in Bcl-2 expression, and dasatinib inhibited ERα at the pretranslational level. ERα was associated with EGFR in dasatinib-treated HNSCC cells. Furthermore, the xenograft model showed that dasatinib inhibited HSC3 tumor growth through in vivo down-regulation of EGFR and ERα. In conclusion, degradation of EGFR is a novel mechanism responsible for dasatinib-induced apoptosis in HNSCC cells.

  9. Kinin B1 receptors mediate depression-like behavior response in stressed mice treated with systemic E. coli lipopolysaccharide

    OpenAIRE

    Viana, Alice F; Maciel, Izaque S; Dornelles, Fabiana N; Figueiredo, Claudia P; Siqueira, Jarbas M; Campos, Maria M; João B Calixto

    2010-01-01

    Background Kinin B1 receptors are inducible molecules up-regulated after inflammatory stimuli. This study evaluated the relevance of kinin B1 receptors in a mouse depression behavior model. Methods Mice were exposed to a 5-min swimming session, and 30 min later they were injected with E. coli lipopolysaccharide (LPS). Depression-like behavior was assessed by determining immobility time in a tail suspension test. Different brain structures were collected for molecular and immunohistochemical s...

  10. p85α recruitment by the CD300f phosphatidylserine receptor mediates apoptotic cell clearance required for autoimmunity suppression

    Science.gov (United States)

    Tian, Linjie; Choi, Seung-Chul; Murakami, Yousuke; Allen, Joselyn; Morse, Herbert C., III; Qi, Chen-Feng; Krzewski, Konrad; Coligan, John E.

    2014-01-01

    Apoptotic cell (AC) clearance is essential for immune homeostasis. Here we show that mouse CD300f (CLM-1) recognizes outer membrane-exposed phosphatidylserine, and regulates the phagocytosis of ACs. CD300f accumulates in phagocytic cups at AC contact sites. Phosphorylation within CD300f cytoplasmic tail tyrosine-based motifs initiates signals that positively or negatively regulate AC phagocytosis. Y276 phosphorylation is necessary for enhanced CD300f-mediated phagocytosis through the recruitment of the p85α regulatory subunit of phosphatidylinositol-3-kinase (PI3K). CD300f-PI3K association leads to activation of downstream Rac/Cdc42 GTPase and mediates changes of F-actin that drive AC engulfment. Importantly, primary macrophages from CD300f-deficient mice have impaired phagocytosis of ACs. The biological consequence of CD300f deficiency is predisposition to autoimmune disease development, as FcγRIIB-deficient mice develop a systemic lupus erythematosus-like disease at a markedly accelerated rate if CD300f is absent. In this report we identify the mechanism and role of CD300f in AC phagocytosis and maintenance of immune homeostasis.

  11. Molecular Mechanisms Underlying β-Adrenergic Receptor-Mediated Cross-Talk between Sympathetic Neurons and Immune Cells

    Directory of Open Access Journals (Sweden)

    Dianne Lorton

    2015-03-01

    Full Text Available Cross-talk between the sympathetic nervous system (SNS and immune system is vital for health and well-being. Infection, tissue injury and inflammation raise firing rates of sympathetic nerves, increasing their release of norepinephrine (NE in lymphoid organs and tissues. NE stimulation of β2-adrenergic receptors (ARs in immune cells activates the cAMP-protein kinase A (PKA intracellular signaling pathway, a pathway that interfaces with other signaling pathways that regulate proliferation, differentiation, maturation and effector functions in immune cells. Immune–SNS cross-talk is required to maintain homeostasis under normal conditions, to develop an immune response of appropriate magnitude after injury or immune challenge, and subsequently restore homeostasis. Typically, β2-AR-induced cAMP is immunosuppressive. However, many studies report actions of β2-AR stimulation in immune cells that are inconsistent with typical cAMP–PKA signal transduction. Research during the last decade in non-immune organs, has unveiled novel alternative signaling mechanisms induced by β2-AR activation, such as a signaling switch from cAMP–PKA to mitogen-activated protein kinase (MAPK pathways. If alternative signaling occurs in immune cells, it may explain inconsistent findings of sympathetic regulation of immune function. Here, we review β2-AR signaling, assess the available evidence for alternative signaling in immune cells, and provide insight into the circumstances necessary for “signal switching” in immune cells.

  12. The GLP-1 Receptor Agonist Exendin-4 and Diazepam Differentially Regulate GABAA Receptor-Mediated Tonic Currents in Rat Hippocampal CA3 Pyramidal Neurons.

    Directory of Open Access Journals (Sweden)

    Sergiy V Korol

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a metabolic hormone that is secreted in a glucose-dependent manner and enhances insulin secretion. GLP-1 receptors are also found in the brain where their signalling affects neuronal activity. We have previously shown that the GLP-1 receptor agonists, GLP-1 and exendin-4 enhanced GABA-activated synaptic and tonic currents in rat hippocampal CA3 pyramidal neurons. The hippocampus is the centre for memory and learning and is important for cognition. Here we examined if exendin-4 similarly enhanced the GABA-activated currents in the presence of the benzodiazepine diazepam. In whole-cell recordings in rat brain slices, diazepam (1 μM, an allosteric positive modulator of GABAA receptors, alone enhanced the spontaneous inhibitory postsynaptic current (sIPSC amplitude and frequency by a factor of 1.3 and 1.6, respectively, and doubled the tonic GABAA current normally recorded in the CA3 pyramidal cells. Importantly, in the presence of exendin-4 (10 nM plus diazepam (1 μM, only the tonic but not the sIPSC currents transiently increased as compared to currents recorded in the presence of diazepam alone. The results suggest that exendin-4 potentiates a subpopulation of extrasynaptic GABAA receptors in the CA3 pyramidal neurons.

  13. Loss of α1,6-fucosyltransferase suppressed liver regeneration: implication of core fucose in the regulation of growth factor receptor-mediated cellular signaling.

    Science.gov (United States)

    Wang, Yuqin; Fukuda, Tomohiko; Isaji, Tomoya; Lu, Jishun; Gu, Wei; Lee, Ho-Hsun; Ohkubo, Yasuhito; Kamada, Yoshihiro; Taniguchi, Naoyuki; Miyoshi, Eiji; Gu, Jianguo

    2015-02-05

    Core fucosylation is an important post-translational modification, which is catalyzed by α1,6-fucosyltransferase (Fut8). Increased expression of Fut8 has been shown in diverse carcinomas including hepatocarcinoma. In this study, we investigated the role of Fut8 expression in liver regeneration by using the 70% partial hepatectomy (PH) model, and found that Fut8 is also critical for the regeneration of liver. Interestingly, we show that the Fut8 activities were significantly increased in the beginning of PH (~4d), but returned to the basal level in the late stage of PH. Lacking Fut8 led to delayed liver recovery in mice. This retardation mainly resulted from suppressed hepatocyte proliferation, as supported not only by a decreased phosphorylation level of epidermal growth factor (EGF) receptor and hepatocyte growth factor (HGF) receptor in the liver of Fut8(-/-) mice in vivo, but by the reduced response to exogenous EGF and HGF of the primary hepatocytes isolated from the Fut8(-/-) mice. Furthermore, an administration of L-fucose, which can increase GDP-fucose synthesis through a salvage pathway, significantly rescued the delayed liver regeneration of Fut8(+/-) mice. Overall, our study provides the first direct evidence for the involvement of Fut8 in liver regeneration.

  14. Histone H4 Lys 20 methyltransferase SET8 promotes androgen receptor-mediated transcription activation in prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Lushuai [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Yanyan; Du, Fengxia [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); Han, Xiao [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xiaohua [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); Niu, Yuanjie [Chawnshang Chang Sex Hormone Research Center, Tianjin Institute of Urology, Tianjin Medical University, Tianjin 300070 (China); Ren, Shancheng, E-mail: renshancheng@gmail.com [Department of Urology, Shanghai Changhai Hospital, Second Military Medical University, Shanghai 200433 (China); Sun, Yingli, E-mail: sunyl@big.ac.cn [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China)

    2014-07-18

    Highlights: • Dihydrotestosterone stimulates H4K20me1 enrichment at the PSA promoter. • SET8 promotes AR-mediated transcription activation. • SET8 interacts with AR and promotes cell proliferation. - Abstract: Histone methylation status in different lysine residues has an important role in transcription regulation. The effect of H4K20 monomethylation (H4K20me1) on androgen receptor (AR)-mediated gene transcription remains unclear. Here we show that AR agonist stimulates the enrichment of H4K20me1 and SET8 at the promoter of AR target gene PSA in an AR dependent manner. Furthermore, SET8 is crucial for the transcription activation of PSA. Co-immunoprecipitation analyses demonstrate that SET8 interacts with AR. Therefore, we conclude that SET8 is involved in AR-mediated transcription activation, possibly through its interaction with AR and H4K20me1 modification.

  15. Smoking particles enhance endothelin A and endothelin B receptor-mediated contractions by enhancing translation in rat bronchi

    DEFF Research Database (Denmark)

    Granström, Bengt W; Xu, Cang-Bao; Nilsson, Elisabeth;

    2006-01-01

    of ETA and ETB receptor mRNA through exposure to DMSO or to nicotine exposure alone occurred, although immunohistochemistry revealed a clear increase in ETA and ETB receptors in the smooth muscle after incubation in the presence of DSP. Taken as a whole, this is seen as the presence of a translation...... segments showed an increased contractility mediated by ETA and ETB receptors, whereas culturing them together with nicotine did not affect their contractility. The up-regulation of their contractility was blunted by cycloheximide treatment, a translational inhibitor. No significant change in the expression...... mechanism. CONCLUSION: The increased contractility of rat bronchi when exposed to DSP appears to be due to a translation mechanism....

  16. Estrogen receptor-mediated neuroprotection: The role of the Alzheimer’s disease-related gene seladin-1

    Directory of Open Access Journals (Sweden)

    Alessandro Peri

    2008-09-01

    Full Text Available Alessandro Peri, Mario SerioDepartment of Clinical Physiopathology, Endocrine Unit, Center for Research, Transfer and High Education on Chronic, Inflammatory, Degenerative and Neoplastic Disorders for the Development of Novel Therapies (DENOThe, University of Florence, Florence, ItalyAbstract: Experimental evidence supports a protective role of estrogen in the brain. According to the fact that Alzheimer’s disease (AD is more common in postmenopausal women, estrogen treatment has been proposed. However, there is no general consensus on the beneficial effect of estrogen or selective estrogen receptor modulators in preventing or treating AD. It has to be said that several factors may markedly affect the efficacy of the treatment. A few years ago, the seladin-1 gene (for selective Alzheimer’s disease indicator-1 has been isolated and found to be down-regulated in brain regions affected by AD. Seladin-1 has been found to be identical to the gene encoding the enzyme 3-beta-hydroxysterol delta-24-reductase, involved in the cholesterol biosynthetic pathway, which confers protection against β-amyloid-mediated toxicity and from oxidative stress, and is an effective inhibitor of caspase-3 activity, a key mediator of apoptosis. Interestingly, we found earlier that the expression of this gene is up-regulated by estrogen. Furthermore, our very recent data support the hypothesis that seladin-1 is a mediator of the neuroprotective effects of estrogen. This review will summarize the current knowledge regarding the neuroprotective effects of seladin-1 and the relationship between this protein and estrogen.Keywords: seladin-1, DHCR24, estrogen, brain, Alzheimer’s disease

  17. P2X2 and P2X5 Receptors Mediate Bladder Hyperesthesia in ICC in Female Overactive Bladder.

    Science.gov (United States)

    Meng, Mingsen; Zheng, Ji; Yan, Junan; Li, Qianwei; Fang, Qiang; Li, Weibing

    2015-06-01

    This study was set to explore the role of P2X2 and P2X5 as the important molecules in sensory afferent of bladder in female overactive bladder (OAB) patients with the bladder hyperesthesia. Sixty-eight OAB patients admitted in Southwest Hospital affiliated to the Third Military Medical University during September, 2011-December, 2012 were selected and included in the experimental group (OAB group) and 30 healthy volunteers during the same period were included as the control group. We recorded voiding diary and urodynamic results, and immunohistochemistry analysis was used to detect P2X2 and P2X5 receptor in interstitial cell of Caja (ICC) in bladder tissue of female OAB patients and healthy volunteers, to tentatively explore the effect of P2X2 and P2X5 in bladder hyperesthesia. Urodynamic study has important diagnostic value in the diagnosis and differential diagnosis of OAB. P2X2 receptor was significantly up-regulated in bladder ICC in OAB group. The blockage of P2X2 receptor could significantly inhibit the contraction of bladder muscle strips, decrease the bladder pressure and the electric discharge of pelvic nerve. PET and urodynamic study showed that micturition desire sense in PAG area of pons in OAB patients was significantly increased compared with the control group. The up-regulation of P2X2 in ICC is an important factor to cause bladder hyperesthesia in OAB patients. PET and urodynamic study indicate that the bladder-originated nervous impulses are important cause of OAB. This study provides a basis for the study of P2X2 receptor in ICC in bladder hyperesthesia of OAB patients.

  18. Specific Endocytosis Blockade of Trypanosoma cruzi Exposed to a Poly-LAcNAc Binding Lectin Suggests that Lectin-Sugar Interactions Participate to Receptor-Mediated Endocytosis

    Science.gov (United States)

    Brosson, Sébastien; Fontaine, Frédéric; Vermeersch, Marjorie; Perez-Morga, David; Pays, Etienne; Bousbata, Sabrina; Salmon, Didier

    2016-01-01

    Trypanosoma cruzi is a protozoan parasite transmitted by a triatomine insect, and causing human Chagas disease in South America. This parasite undergoes a complex life cycle alternating between non-proliferative and dividing forms. Owing to their high energy requirement, replicative epimastigotes of the insect midgut display high endocytic activity. This activity is mainly restricted to the cytostome, by which the cargo is taken up and sorted through the endosomal vesicular network to be delivered to reservosomes, the final lysosomal-like compartments. In African trypanosomes tomato lectin (TL) and ricin, respectively specific to poly-N-acetyllactosamine (poly-LacNAc) and β-D-galactose, allowed the identification of giant chains of poly-LacNAc in N-glycoproteins of the endocytic pathway. We show that in T. cruzi epimastigote forms also, glycoproteins of the endocytic pathway are characterized by the presence of N-linked glycans binding to both ricin and TL. Affinity chromatography using both TL and Griffonia simplicifolia lectin II (GSLII), specific to non-reducing terminal residue of N-acetylglucosamine (GlcNAc), led to an enrichment of glycoproteins of the trypanosomal endocytic pathway. Incubation of live parasites with TL, which selectively bound to the cytostome/cytopharynx, specifically inhibited endocytosis of transferrin (Tf) but not dextran, a marker of fluid endocytosis. Taken together, our data suggest that N-glycan modification of endocytic components plays a crucial role in receptor-mediated endocytosis of T. cruzi. PMID:27685262

  19. Cell Type-Specific Delivery of RNAi by Ligand-Functionalized Curdlan Nanoparticles: Balancing the Receptor Mediation and the Charge Motivation.

    Science.gov (United States)

    Wu, Yinga; Cai, Jia; Han, Jingfen; Baigude, Huricha

    2015-09-30

    Tissue-specific delivery of therapeutic RNAi has great potential for clinical applications. Receptor-mediated endocytosis plays a crucial role in targeted delivery of biotherapeutics including short interfering RNA (siRNA). Previously we reported a novel Curdlan-based nanoparticle for intracellular delivery of siRNA. Here we designed a nanoparticle based on ligand-functionalized Curdlan. Disaccharides were site-specifically conjugated to 6-deoxy-6-amino Curdlan, and the cell line specificity, cellular uptake, cytotoxicity, and siRNA delivery efficiency of the corresponding disaccharide-modified 6-deoxy-6-amino-Curdlan were investigated. Observation by fluorescence microscopy as well as flow cytometry showed that galactose-containing Curdlan derivatives delivered fluorescently labeled short nucleic acid to HepG2 cells expressing ASGPR receptor but not in other cells lacking surface ASGPR protein. Moreover, highly galactose-substituted Curdlan derivatives delivered siRNA specifically to ASGPR-expressing cells and induced RNAi activities, silencing endogenous GAPDH gene expression. Our data demonstrated that galactose-functionalized 6-deoxy-6-amino-Curdlan is a promising carrier for short therapeutic nucleic acids for clinical applications.

  20. CD36 is not involved in scavenger receptor-mediated endocytic uptake of glycolaldehyde- and methylglyoxal-modified proteins by liver endothelial cells.

    Science.gov (United States)

    Nakajou, Keisuke; Horiuchi, Seikoh; Sakai, Masakazu; Hirata, Kenshiro; Tanaka, Makiko; Takeya, Motohiro; Kai, Toshiya; Otagiri, Masaki

    2005-05-01

    Circulating proteins modified by advanced glycation end-products (AGE) are mainly taken up by liver endothelial cells (LECs) via scavenger receptor-mediated endocytosis. Endocytic uptake of chemically modified proteins by macrophages and macrophage-derived cells is mediated by class A scavenger receptor (SR-A) and CD36. In a previous study using SR-A knockout mice, we demonstrated that SR-A is not involved in endocytic uptake of AGE proteins by LECs [Matsumoto et al. (2000) Biochem. J. 352, 233-240]. The present study was conducted to determine the contribution of CD36 to this process. Glycolaldehyde-modified BSA (GA-BSA) and methylglyoxal-modified BSA (MG-BSA) were used as AGE proteins. 125I-GA-BSA and 125I-MG-BSA underwent endocytic degradation by these cells at 37 degrees C, and this process was inhibited by several ligands for the scavenger receptors. However, this endocytic uptake of 125I-GA-BSA by LECs was not inhibited by a neutralizing anti-CD36 antibody. Similarly, hepatic uptake of (111)In-GA-BSA after its intravenous injection was not significantly attenuated by co-administration of the anti-CD36 antibody. These results clarify that CD36 does not play a significant role in elimination of GA-BSA and MG-BSA from the circulation, suggesting that the receptor involved in endocytic uptake of circulating AGE proteins by LEC is not SR-A or CD36.

  1. The plasma concentration of HDL-associated apoM is influenced by LDL receptor-mediated clearance of apoB-containing particles

    DEFF Research Database (Denmark)

    Christoffersen, Christina; Benn, Marianne; Christensen, Pernille Møller;

    2012-01-01

    ApoM is mainly associated with HDL. Nevertheless, we have consistently observed positive correlations of apoM with plasma LDL cholesterol in humans. Moreover, LDL receptor deficiency is associated with increased plasma apoM in mice. Here, we tested the idea that plasma apoM concentrations...... are affected by the rate of LDL receptor-mediated clearance of apoB-containing particles. We measured apoM in humans each carrying one of three different LDL receptor mutations (n = 9) or the apoB3500 mutation (n = 12). These carriers had increased plasma apoM (1.34 ± 0.13 µM, P = 0.003, and 1.23 ± 0.10 µM, P...... = 0.02, respectively) as compared with noncarriers (0.93 ± 0.04 µM). When we injected human apoM-containing HDL into Wt (n = 6) or LDL receptor-deficient mice (n = 6), the removal of HDL-associated human apoM was delayed in the LDL receptor-deficient mice. After 2 h, 54 ± 5% versus 90 ± 8% (P

  2. Metabolism of glycosylated human salivary amylase: in vivo plasma clearance by rat hepatic endothelial cells and in vitro receptor mediated pinocytosis by rat macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Niesen, T.E.; Alpers, D.H.; Stahl, P.D.; Rosenblum, J.L.

    1984-09-01

    Salivary-type amylase normally comprises about 60% of the amylase activity in human serum, but only a small fraction is a glycosylated isoenzyme (amylase A). In contrast, 1/3 of amylase in human saliva is glycosylated. Since glycosylation can affect circulatory clearance, we studied the clearance of amylase A in rats and its uptake by rat alveolar macrophages. Following intravenous injection, /sup 125/I-labeled amylase A disappeared rapidly from plasma (t 1/2 . 9 min) and accumulated in the liver. Simultaneous injection of mannose-albumin slowed its clearance to a rate comparable to that of /sup 125/I-labeled nonglycosylated salivary amylase (t 1/2 . 45 min). In contrast, galactose-albumin had no effect. Electron microscope autoradiography of the liver following injection of /sup 125/I-labeled amylase A revealed a localization of grains over the hepatic endothelial cells. In vitro studies indicated that amylase A is taken up by alveolar macrophages via receptor-mediated pinocytosis. Uptake was linear over time, saturable, and inhibited by mannan and mannose-albumin, but not by galactose-albumin. We conclude that amylase A, which is a naturally occurring human glycoprotein with at most three terminal L-fucose residues per molecule, is recognized in rats by a mannose receptor located on hepatic endothelial cells. We speculate that this receptor, by rapidly clearing circulating amylase A, may be responsible for the low level of amylase A in human serum.

  3. Mechanical stress triggers cardiomyocyte autophagy through angiotensin II type 1 receptor-mediated p38MAP kinase independently of angiotensin II.

    Directory of Open Access Journals (Sweden)

    Li Lin

    Full Text Available Angiotensin II (Ang II type 1 (AT1 receptor is known to mediate a variety of physiological actions of Ang II including autophagy. However, the role of AT1 receptor in cardiomyocyte autophagy triggered by mechanical stress still remains elusive. The aim of this study was therefore to examine whether and how AT1 receptor participates in cardiomyocyte autophagy induced by mechanical stresses. A 48-hour mechanical stretch and a 4-week transverse aorta constriction (TAC were imposed to cultured cardiomyocytes of neonatal rats and adult male C57B/L6 mice, respectively, to induce cardiomyocyte hypertrophy prior to the assessment of cardiomyocyte autophagy using LC3b-II. Losartan, an AT1 receptor blocker, but not PD123319, the AT2 inhibitor, was found to significantly reduce mechanical stretch-induced LC3b-II upregulation. Moreover, inhibition of p38MAP kinase attenuated not only mechanical stretch-induced cardiomyocyte hypertrophy but also autophagy. To the contrary, inhibition of ERK and JNK suppressed cardiac hypertrophy but not autophagy. Intriguingly, mechanical stretch-induced autophagy was significantly inhibited by Losartan in the absence of Ang II. Taken together, our results indicate that mechanical stress triggers cardiomyocyte autophagy through AT1 receptor-mediated activation of p38MAP kinase independently of Ang II.

  4. Escitalopram attenuates β-amyloid-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3β pathway.

    Science.gov (United States)

    Wang, Yan-Juan; Ren, Qing-Guo; Gong, Wei-Gang; Wu, Di; Tang, Xiang; Li, Xiao-Li; Wu, Fang-Fang; Bai, Feng; Xu, Lin; Zhang, Zhi-Jun

    2016-03-22

    Tau hyperphosphorylation is an important pathological feature of Alzheimer's disease (AD). To investigate whether escitalopram could inhibit amyloid-β (Aβ)-induced tau hyperphosphorylation and the underlying mechanisms, we treated the rat primary hippocampal neurons with Aβ1-42 and examined the effect of escitalopram on tau hyperphosphorylation. Results showed that escitalopram decreased Aβ1-42-induced tau hyperphosphorylation. In addition, escitalopram activated the Akt/GSK-3β pathway, and the PI3K inhibitor LY294002 blocked the attenuation of tau hyperphosphorylation induced by escitalopram. Moreover, the 5-HT1A receptor agonist 8-OH-DPAT also activated the Akt/GSK-3β pathway and decreased Aβ1-42-induced tau hyperphosphorylation. Furthermore, the 5-HT1A receptor antagonist WAY-100635 blocked the activation of Akt/GSK-3β pathway and the attenuation of tau hyperphosphorylation induced by escitalopram. Finally, escitalopram improved Aβ1-42 induced impairment of neurite outgrowth and spine density, and reversed Aβ1-42 induced reduction of synaptic proteins. Our results demonstrated that escitalopram attenuated Aβ1-42-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3β pathway. PMID:26950279

  5. Somatostatin Receptor-Mediated Tumor-Targeting Nanocarriers Based on Octreotide-PEG Conjugated Nanographene Oxide for Combined Chemo and Photothermal Therapy.

    Science.gov (United States)

    Zhang, Xuyuan; Yang, Chongyin; Zhou, Jianping; Huo, Meirong

    2016-07-01

    Nano-sized in vivo active targeting drug delivery systems have been developed to a high anti-tumor efficacy strategy against certain cancer-cells-specific. Graphene based nanocarriers with unique physical and chemical properties have shown significant potentials in this aspect. Here, octreotide (OCT), an efficient biotarget molecule, is conjugated to PEGylated nanographene oxide (NGO) drug carriers for the first time. The obtained NGO-PEG-OCT complex shows low toxicity and excellent stability in vivo and is able to achieve somatostatin receptor-mediated tumor-specific targeting delivery. Owing to the high loading efficiency and accurate targeting delivery of anti-cancer drug doxorubicin (DOX), our DOX loaded NGO-PEG-OCT complex offers a remarkably improved cancer-cell-specific cellular uptake, chemo-cytotoxicity, and decreased systemic toxicity compared to free DOX or NGO-PEG. More importantly, due to its strong near-infrared absorption, the NGO-PEG-OCT complex further enhances efficient photothermal ablation of tumors, delivering combined chemo and photothermal therapeutic effect against cancer cells. PMID:27244649

  6. Optogenetic Evocation of Field Inhibitory Postsynaptic Potentials in Hippocampal Slices: A Simple and Reliable Approach for Studying Pharmacological Effects on GABAA and GABAB Receptor-Mediated Neurotransmission

    Directory of Open Access Journals (Sweden)

    Julien eDine

    2014-01-01

    Full Text Available The GABAergic system is the main source of inhibition in the mammalian brain. Consequently, much effort is still made to develop new modulators of GABAergic synaptic transmission. In contrast to glutamatergic postsynaptic potentials (PSPs, accurate monitoring of GABA receptor-mediated PSPs (GABAR-PSPs and their pharmacological modulation in brain tissue invariably requires the use of intracellular recording techniques. However, these techniques are expensive, time- and labor-consuming, and, in case of the frequently employed whole-cell patch-clamp configuration, impact on intracellular ion concentrations, signaling cascades, and pH buffering systems. Here, we describe a novel approach to circumvent these drawbacks. In particular, we demonstrate in mouse hippocampal slices that selective optogenetic activation of interneurons leads to prominent field inhibitory GABAAR- and GABABR-PSPs in area CA1 which are easily and reliably detectable by a single extracellular recording electrode. The field PSPs exhibit typical temporal and pharmacological characteristics, display pronounced paired-pulse depression, and remain stable over many consecutive evocations. Additionally validating the methodological value of this approach, we further show that the neuroactive steroid 5-THDOC (5 µM shifts the inhibitory GABAAR-PSPs towards excitatory ones.

  7. Adenosine A2B receptor-mediated leukemia inhibitory factor release from astrocytes protects cortical neurons against excitotoxicity

    Directory of Open Access Journals (Sweden)

    Moidunny Shamsudheen

    2012-08-01

    Full Text Available Abstract Background Neuroprotective and neurotrophic properties of leukemia inhibitory factor (LIF have been widely reported. In the central nervous system (CNS, astrocytes are the major source for LIF, expression of which is enhanced following disturbances leading to neuronal damage. How astrocytic LIF expression is regulated, however, has remained an unanswered question. Since neuronal stress is associated with production of extracellular adenosine, we investigated whether LIF expression in astrocytes was mediated through adenosine receptor signaling. Methods Mouse cortical neuronal and astrocyte cultures from wild-type and adenosine A2B receptor knock-out animals, as well as adenosine receptor agonists/antagonists and various enzymatic inhibitors, were used to study LIF expression and release in astrocytes. When needed, a one-way analysis of variance (ANOVA followed by Bonferroni post-hoc test was used for statistical analysis. Results We show here that glutamate-stressed cortical neurons induce LIF expression through activation of adenosine A2B receptor subtype in cultured astrocytes and require signaling of protein kinase C (PKC, mitogen-activated protein kinases (MAPKs: p38 and ERK1/2, and the nuclear transcription factor (NF-κB. Moreover, LIF concentration in the supernatant in response to 5′-N-ethylcarboxamide (NECA stimulation was directly correlated to de novo protein synthesis, suggesting that LIF release did not occur through a regulated release pathway. Immunocytochemistry experiments show that LIF-containing vesicles co-localize with clathrin and Rab11, but not with pHogrin, Chromogranin (CgA and CgB, suggesting that LIF might be secreted through recycling endosomes. We further show that pre-treatment with supernatants from NECA-treated astrocytes increased survival of cultured cortical neurons against glutamate, which was absent when the supernatants were pre-treated with an anti-LIF neutralizing antibody. Conclusions

  8. Toll-Like Receptor Mediated Modulation of T Cell Response by Commensal Intestinal Microbiota as a Trigger for Autoimmune Arthritis

    Directory of Open Access Journals (Sweden)

    Rebecca Rogier

    2015-01-01

    Full Text Available In autoimmune diseases, a disturbance of the balance between T helper 17 (Th17 and regulatory T cells (Tregs is often observed. This disturbed balance is also the case in rheumatoid arthritis (RA. Genetic predisposition to RA confers the presence of several polymorphisms mainly regulating activation of T lymphocytes. However, the presence of susceptibility factors is neither necessary nor sufficient to explain the disease development, emphasizing the importance of environmental factors. Multiple studies have shown that commensal gut microbiota is of great influence on immune homeostasis and can trigger the development of autoimmune diseases by favoring induction of Th17 cells over Tregs. However the mechanism by which intestinal microbiota influences the Th cell balance is not completely understood. Here we review the current evidence supporting the involvement of commensal intestinal microbiota in rheumatoid arthritis, along with a potential role of Toll-like receptors (TLRs in modulating the relevant Th cell responses to trigger autoimmunity. A better understanding of TLR triggering by intestinal microbiota and subsequent T cell activation might offer new perspectives for manipulating the T cell response in RA patients and may lead to the discovery of new therapeutic targets or even preventive measures.

  9. Pancreatic cancer cells require an EGF receptor-mediated autocrine pathway for proliferation in serum-free conditions

    Science.gov (United States)

    Murphy, L O; Cluck, M W; Lovas, S; Ötvös, F; Murphy, R F; Schally, A V; Permert, J; Larsson, J; Knezetic, J A; Adrian, T E

    2001-01-01

    In-vitro and in-vivo studies have shown that autocrine growth factors and receptors are frequently expressed in human malignancies. Few of these studies, however, provide evidence that the identified autocrine pathway is functional. In this study, a functional autocrine growth pathway in pancreatic cancer has been identified using an in-vitro cell culture system. When pancreatic cancer cells were grown without change of medium, proliferation was greater than when either medium was replaced frequently (HPAF, CAPAN-2, PANC-1 or SW1990) or cells were grown in the presence of the EGF receptor tyrosine kinase inhibitor AG1478 or the MEK inhibitor PD098059 (HPAF or CAPAN-2). Activity of extracellular-regulated kinases (ERK) 1 and 2 and c- jun and c- fos mRNA levels were significantly elevated in CAPAN-2 cells cultured continuously in serum-free medium. Collectively, the observations indicate that the EGF receptor and the ERK MAP kinase pathway mediate autocrine signals. In contrast to previous reports, the GRP and IGF-I receptors were shown not to be required for autocrine effects on pancreatic cancer cell proliferation. Autocrine stimulation of the EGF receptor can contribute to sustained mitogenic activity and proliferation of pancreatic cancer cells. © 2001 Cancer Research Campaign http://www.bjcancer.com PMID:11286473

  10. In adult female hamsters hypothyroidism stimulates D1 receptor-mediated breathing without altering D1 receptor expression.

    Science.gov (United States)

    Schlenker, Evelyn H; Del Rio, Rodrigo; Schultz, Harold D

    2015-11-01

    Hypothyroidism affects cardiopulmonary regulation and function of dopaminergic receptors. Here we evaluated effects of 5 months of hypothyroidism on dopamine D1 receptor modulation of breathing in female hamsters using a D1 receptor antagonist SCH 23390. Euthyroid hamsters (EH) served as controls. Results indicated that hypothyroid female hamsters (HH) exhibited decreased body weights and minute ventilation (VE) following hypoxia due to decreased frequency of breathing (F). Moreover, SCH 23390 administration in HH increased VE by increasing tidal volume during exposure to air, hypoxia and following hypoxia. Relative to vehicle, SCH 23390 treatment decreased body temperature and hypoxic VE responsiveness in both groups. In EH, SCH 23390 decreased F in air, hypoxia and post hypoxia, and VE during hypoxia trended to decrease (P=0.053). Finally, expression of D1 receptor protein was not different between the two groups in any region evaluated. Thus, hypothyroidism in older female hamsters affected D1 receptor modulation of ventilation differently relative to euthyroid animals, but not expression of D1 receptors.

  11. Activation of retinoid receptor-mediated signaling ameliorates diabetes-induced cardiac dysfunction in Zucker diabetic rats.

    Science.gov (United States)

    Guleria, Rakeshwar S; Singh, Amar B; Nizamutdinova, Irina T; Souslova, Tatiana; Mohammad, Amin A; Kendall, Jonathan A; Baker, Kenneth M; Pan, Jing

    2013-04-01

    Diabetic cardiomyopathy (DCM) is a significant contributor to the morbidity and mortality associated with diabetes and metabolic syndrome. Retinoids, through activation of retinoic acid receptor (RAR) and retinoid x receptor (RXR), have been linked to control glucose and lipid homeostasis, with effects on obesity and diabetes. However, the functional role of RAR and RXR in the development of DCM remains unclear. Zucker diabetic fatty (ZDF) and lean rats were treated with Am580 (RARα agonist) or LGD1069 (RXR agonist) for 16 weeks, and cardiac function and metabolic alterations were determined. Hyperglycemia, hyperlipidemia and insulin resistance were observed in ZDF rats. Diabetic cardiomyopathy was characterized in ZDF rats by increased oxidative stress, apoptosis, fibrosis, inflammation, activation of MAP kinases and NF-κB signaling and diminished Akt phosphorylation, along with decreased glucose transport and increased cardiac lipid accumulation, and ultimately diastolic dysfunction. Am580 and LGD1069 attenuated diabetes-induced cardiac dysfunction and the pathological alterations, by improving glucose tolerance and insulin resistance; facilitating Akt activation and glucose utilization, and attenuating oxidative stress and interrelated MAP kinase and NF-κB signaling pathways. Am580 inhibited body weight gain, attenuated the increased cardiac fatty acid uptake, β-oxidation and lipid accumulation in the hearts of ZDF rats. However, LGD1069 promoted body weight gain, hyperlipidemia and cardiac lipid accumulation. In conclusion, our data suggest that activation of RAR and RXR may have therapeutic potential in the treatment of diabetic cardiomyopathy. However, further studies are necessary to clarify the role of RAR and RXR in the regulation of lipid metabolism and homeostasis.

  12. Interplay between BCL10, MALT1 and IkappaBalpha during T-cell-receptor-mediated NFkappaB activation.

    Science.gov (United States)

    Carvalho, Gabrielle; Le Guelte, Armelle; Demian, Catherine; Vazquez, Aimé; Gavard, Julie; Bidère, Nicolas

    2010-07-15

    T-cell-receptor (TCR) signalling to NFkappaB requires the assembly of a large multiprotein complex containing the serine/threonine kinase CK1alpha, the scaffold protein CARMA1, the heterodimer BCL10-MALT1 (the CBM complex) and the IkappaB kinase complex (IKK). Although the mechanisms regulating recruitment and activation of IKK within the CBM microenvironment have been extensively studied, there is little understanding of how IKK subsequently binds and phosphorylates IkappaBalpha, the inhibitor of NFkappaB, to promote IkappaBalpha ubiquitylation and proteasomal degradation. Here, we show that BCL10, MALT1 and IKK inducibly associate with IkappaBalpha in a complex that is physically distinct from the early CK1alpha-CBM signalosome. This IkappaBalpha-containing complex probably maturates from the CBM, because siRNA-based knockdown of CARMA1, CK1alpha and BCL10 hampered its assembly, leading to a reduction in NFkappaB activation. By contrast, CK1alpha normally recruited both BCL10 and ubiquitylated species of MALT1 when IkappaBalpha levels were reduced. However, knockdown of IkappaBalpha led to an altered ubiquitylation profile of BCL10-MALT1 combined with a defect in MALT1 reorganisation within large cytoplasmic structures, suggesting that, following stimulation, IkappaBalpha might also participate in MALT1 recycling. Altogether, our data suggest a two-step mechanism to connect active IKK to IkappaBalpha, and further unveil a potential role for IkappaBalpha in resetting TCR-mediated signalling. PMID:20551178

  13. Kinin B1 receptors mediate depression-like behavior response in stressed mice treated with systemic E. coli lipopolysaccharide

    Directory of Open Access Journals (Sweden)

    Campos Maria M

    2010-12-01

    Full Text Available Abstract Background Kinin B1 receptors are inducible molecules up-regulated after inflammatory stimuli. This study evaluated the relevance of kinin B1 receptors in a mouse depression behavior model. Methods Mice were exposed to a 5-min swimming session, and 30 min later they were injected with E. coli lipopolysaccharide (LPS. Depression-like behavior was assessed by determining immobility time in a tail suspension test. Different brain structures were collected for molecular and immunohistochemical studies. Anhedonia was assessed by means of a sucrose intake test. Results Our protocol elicited an increase in depression-like behavior in CF1 mice, as assessed by the tail-suspension test, at 24 h. This behavior was significantly reduced by treatment with the selective B1 receptor antagonists R-715 and SSR240612. Administration of SSR240612 also prevented an increase in number of activated microglial cells in mouse hippocampus, but did not affect a reduction in expression of mRNA for brain-derived neurotrophic factor. The increased immobility time following LPS treatment was preceded by an enhancement of hippocampal and cortical B1 receptor mRNA expression (which were maximal at 1 h, and a marked production of TNFα in serum, brain and cerebrospinal fluid (between 1 and 6 h. The depression-like behavior was virtually abolished in TNFα p55 receptor-knockout mice, and increased B1 receptor mRNA expression was completely absent in this mouse strain. Furthermore, treatment with SSR240612 was also effective in preventing anhedonia in LPS-treated mice, as assessed using a sucrose preference test. Conclusion Our data show, for the first time, involvement of kinin B1 receptors in depressive behavioral responses, in a process likely associated with microglial activation and TNFα production. Thus, selective and orally active B1 receptor antagonists might well represent promising pharmacological tools for depression therapy.

  14. Adenosine A1 receptor-mediated transactivation of the EGF receptor produces a neuroprotective effect on cortical neurons in vitro

    Institute of Scientific and Technical Information of China (English)

    Ke-qiang XIE; Li-min ZHANG; Yan CAO; Jun ZHU; Lin-yin FENG

    2009-01-01

    Aim:To understand the mechanism of the transactivation of the epidermal growth factor receptor (EGFR) mediated by the adenosine A1 receptor (A1R).Methods:Primary cultured rat cortical neurons subjected to oxygen-glucose deprivation (OGD) and HEK293/A1R cells were treated with the A1R-specific agonist N6-cyclopentyladenosine (CPA).Phospho-EGFR,Akt,and ERK1/2 were observed by Western blot.An interaction between EGFR and AIR was detected using immunoprecipitation and immunocytochemistry.Results:The A1R agonist CPA causes protein kinase B (Akt) activation and protects primary cortical neurons from oxygen-glucose deprivation (OGD) insult.A1R and EGFR co-localize in the membranes of neurons and form an immunocomplex.A1R stimulation induces significant EGFR phosphorylation via a P13K and Src kinase signaling pathway;this stimulation provides a neuroprotective effect in cortical neurons.CPA leads to sustained phosphorylation of extracellularly regulated kinases 1 and 2 (ERK1/2) in cortical neurons,but only to transient phosphorylation in HEK 293/A1R cells.The response to the AtR agonist is mediated primarily through EGFR trans-activation that is dependent on pertussis toxin (PTX)-sensitive G1 protein and metalloproteases in HEK 293/A1R.Conclusion:A1R-mediated EGFR transactivation confers a neuroprotective effect in primary cortical neurons.P13 kinase and Src kinase play pivotal roles in this response.

  15. Interplay between BCL10, MALT1 and IkappaBalpha during T-cell-receptor-mediated NFkappaB activation.

    Science.gov (United States)

    Carvalho, Gabrielle; Le Guelte, Armelle; Demian, Catherine; Vazquez, Aimé; Gavard, Julie; Bidère, Nicolas

    2010-07-15

    T-cell-receptor (TCR) signalling to NFkappaB requires the assembly of a large multiprotein complex containing the serine/threonine kinase CK1alpha, the scaffold protein CARMA1, the heterodimer BCL10-MALT1 (the CBM complex) and the IkappaB kinase complex (IKK). Although the mechanisms regulating recruitment and activation of IKK within the CBM microenvironment have been extensively studied, there is little understanding of how IKK subsequently binds and phosphorylates IkappaBalpha, the inhibitor of NFkappaB, to promote IkappaBalpha ubiquitylation and proteasomal degradation. Here, we show that BCL10, MALT1 and IKK inducibly associate with IkappaBalpha in a complex that is physically distinct from the early CK1alpha-CBM signalosome. This IkappaBalpha-containing complex probably maturates from the CBM, because siRNA-based knockdown of CARMA1, CK1alpha and BCL10 hampered its assembly, leading to a reduction in NFkappaB activation. By contrast, CK1alpha normally recruited both BCL10 and ubiquitylated species of MALT1 when IkappaBalpha levels were reduced. However, knockdown of IkappaBalpha led to an altered ubiquitylation profile of BCL10-MALT1 combined with a defect in MALT1 reorganisation within large cytoplasmic structures, suggesting that, following stimulation, IkappaBalpha might also participate in MALT1 recycling. Altogether, our data suggest a two-step mechanism to connect active IKK to IkappaBalpha, and further unveil a potential role for IkappaBalpha in resetting TCR-mediated signalling.

  16. Smoking particles enhance endothelin A and endothelin B receptor-mediated contractions by enhancing translation in rat bronchi

    Directory of Open Access Journals (Sweden)

    Vikman Petter

    2006-03-01

    Full Text Available Abstract Background Smoking is known to cause chronic inflammatory changes in the bronchi and to contribute to airway hyper-reactivity, such as in bronchial asthma. To study the effect of smoking on the endothelin system in rat airways, bronchial segments were exposed to DMSO-soluble smoking particles (DSP from cigarette smoke, to nicotine and to DMSO, respectively. Methods Isolated rat bronchial segments were cultured for 24 hours in the presence or absence of DSP, nicotine or DMSO alone. Contractile responses to sarafotoxin 6c (a selective agonist for ETB receptors and endothelin-1 (an ETA and ETB receptor agonist were studied by use of a sensitive myograph. Before ET-1 was introduced, the ETB receptors were desensitized by use of S6c. The remaining contractility observed was considered to be the result of selective activation of the ETA receptors. ETA and ETB receptor mRNA expression was analyzed using real-time quantitative PCR. The location and concentration of ETA and ETB receptors were studied by means of immunohistochemistry together with confocal microscopy after overnight incubation with selective antibodies. Results After being cultured together with DSP for 24 hours the bronchial segments showed an increased contractility mediated by ETA and ETB receptors, whereas culturing them together with nicotine did not affect their contractility. The up-regulation of their contractility was blunted by cycloheximide treatment, a translational inhibitor. No significant change in the expression of ETA and ETB receptor mRNA through exposure to DMSO or to nicotine exposure alone occurred, although immunohistochemistry revealed a clear increase in ETA and ETB receptors in the smooth muscle after incubation in the presence of DSP. Taken as a whole, this is seen as the presence of a translation mechanism. Conclusion The increased contractility of rat bronchi when exposed to DSP appears to be due to a translation mechanism.

  17. Receptor subtype involved in α1-adrenergic receptor-mediated Ca2+ sig-naling in cardiomyocytes

    Institute of Scientific and Technical Information of China (English)

    Da-li LUO; Jian GAO; Lin-lin FAN; Yu TANG; You-yi ZHANG; Qi-de HAN

    2007-01-01

    Aim: The enhancement of intracellular Ca2+ signaling in response to α1-adrener-gic receptor (α1-AR) stimulation is an essential signal transduction event in the regulation of cardiac functions, such as cardiac growth, cardiac contraction, and cardiac adaptation to various situations. The present study was intended to determine the role(s) of the α1-AR subtype(s) in mediating this response. Methods: We evaluated the effects of subtype-specific agonists and antagonists of the α1- AR on the intracellular Ca2+ signaling of neonatal rat ventricular myocytes using a confocal microscope. Results: After being cultured for 48 h, the myocytes exhibited spontaneous local Ca2+ release, sparks, and global Ca2+ transients. The activation of the α1-AR with phenylephrine, a selective agonist of the α1-AR, dose-dependently increased the frequency of Ca2+ transients with an EC50 value of 2.3 μmol/L. Blocking the α1A-AR subtype with 5-methyhirapidil (5-Mu) inhi-bited the stimulatory effect of phenylephrine with an IC50 value of 6.7 nmol/L. In contrast, blockade of the α1B-AR and α1D-AR subtypes with chloroethylclonidine and BMY 7378, respectively, did not affect the phenylephrine effect. Similarly, the local Ca2+ spark numbers were also increased by the activation of theα1-AR, and this effect could be abolished selectively by 5-Mu. More importantly, A61603, a novel selective α1A-AR agonist, mimicked the effects of phenylephrine, but with more potency (EC50 value =6.9 nmol/L) in the potentiation of Ca2+ transients, and blockade of the α1A-AR by 5-Mu caused abolishment of its effects. Conclusion: These results indicate that α1-adrenergic stimulation of intracellular Ca2+ activity is mediated selectively by the α1A-AR.

  18. Signal transduction regulating meristem development in Arabidopsis. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Cark, Steven E.

    2003-09-10

    Research support by DE-FG02-96ER20227 focused on the CLV loci and their regulation of organ formation at the Arabidopsis shoot meristem. Shoot meristem function is central to plant development as all of the above-ground organs and tissues of the plant are derived post-embryonically from the shoot meristem. At the shoot meristem, stem cells are maintained, and progeny cells undergo a switch toward differentiation and organ formation. The CLV loci, represented by three genes CLV1, CLV2 and CLV3 are key regulators of meristem development. Each of the CLV loci encode a putative receptor-mediated signaling component. When this work began, virtually nothing was known about receptor-mediated signaling in plants. Thus, our goal was to both characterize these genes and the proteins they encode as regulators of meristem development, and to investigate how receptor-mediated signaling might function in plants. Our work lead to several major publications that were significant contributions to understanding this system.

  19. NR4A nuclear receptors mediate carnitine palmitoyltransferase 1A gene expression by the rexinoid HX600

    Energy Technology Data Exchange (ETDEWEB)

    Ishizawa, Michiyasu [Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610 (Japan); Kagechika, Hiroyuki [Graduate School of Biomedical Science, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Makishima, Makoto, E-mail: makishima.makoto@nihon-u.ac.jp [Division of Biochemistry, Department of Biomedical Sciences, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610 (Japan)

    2012-02-24

    Highlights: Black-Right-Pointing-Pointer The function of RXR heterodimers with NR4 receptors remains unknown. Black-Right-Pointing-Pointer The RXR ligand HX600 induces expression of carnitine palmitoyltransferase 1A (CPT1A). Black-Right-Pointing-Pointer HX600-induced CPT1A expression is mediated by the NR4 receptors, Nur77 and NURR1. Black-Right-Pointing-Pointer CPT1A induction by HX600 is not mediated by de novo protein synthesis. Black-Right-Pointing-Pointer CPT1A could be a target of the Nur77-RXR and NURR1-RXR heterodimers. -- Abstract: Retinoid X receptors (RXRs) are members of the nuclear receptor superfamily and can be activated by 9-cis retinoic acid (9CRA). RXRs form homodimers and heterodimers with other nuclear receptors such as the retinoic acid receptor and NR4 subfamily nuclear receptors, Nur77 and NURR1. Potential physiological roles of the Nur77-RXR and NURR1-RXR heterodimers have not been elucidated. In this study, we identified a gene regulated by these heterodimers utilizing HX600, a selective RXR agonist for Nur77-RXR and NURR1-RXR. While 9CRA induced many genes, including RAR-target genes, HX600 effectively induced only carnitine palmitoyltransferase 1A (CPT1A) in human teratocarcinoma NT2/D1 cells, which express RXR{alpha}, Nur77 and NURR1. HX600 also increased CPT1A expression in human embryonic kidney (HEK) 293 cells and hepatocyte-derived HepG2 cells. Although HX600 induced CPT1A less effectively than 9CRA, overexpression of Nur77 or NURR1 increased the HX600 response to levels similar to 9CRA in NT2/D1 and HEK293 cells. A dominant-negative form of Nur77 or NURR1 repressed the induction of CPT1A by HX600. A protein synthesis inhibitor did not alter HX600-dependent CPT1A induction. Thus, the rexinoid HX600 directly induces expression of CPT1A through a Nur77 or NURR1-mediated mechanism. CPT1A, a gene involved in fatty acid {beta}-oxidation, could be a target of RXR-NR4 receptor heterodimers.

  20. Dual effects of daidzein on chicken hepatic vitellogenin II expression and estrogen receptor-mediated transactivation in vitro.

    Science.gov (United States)

    Ni, Ying-Dong; Hong, Wen-Jie; Zhou, Yu-Chuan; Grossmann, Roland; Zhao, Ru-Qian

    2010-03-01

    Two in vitro systems were employed to delineate the estrogenic activity of daidzein (Da), alone or in combination with high or low concentrations of estrogen in two cell types possessing different estrogen-receptor (ER) isoforms, ERalpha and/or ERbeta: (1) vitellogenin II (VTG), the egg yolk precursor protein and the endpoint biomarker for estrogenicity, in chicken primary hepatocytes, and (2) CHO-K1 cells transiently co-transfected with ERalpha or ERbeta and estrogen-response elements (ERE) linked to a luciferase reporter gene. Da (100 microM) alone induced VTG mRNA expression in chicken hepatocytes, albeit with much less potency compared to estradiol (E(2)). Da exhibited different effects in the presence of 1 microM and 10 microM E(2). At a concentration of 100 microM, Da enhanced 1 microM E(2)-induced VTG transcription by 2.4-fold, but significantly inhibited 10 microM E(2)-induced VTG mRNA expression in a dose-dependent fashion from 1 to 100 microM. Tamoxifen completely blocked the estrogenic effect of daidzein, alone or in combination with 1 microM of E(2), but did not influence its anti-estrogenic effect on 10 microM E(2)-induced VTG mRNA expression. Furthermore, neither E(2) nor daidzein, alone or in combination, affected ERalpha mRNA expression, yet all the treatments significantly up-regulated ERbeta mRNA expression in chicken hepatocytes. E(2) effectively triggered estrogen-response elements (ERE)-driven reporter gene transactivation in CHO-K1 cells expressing ERalpha or ERbeta and showed much greater potency with ERalpha than with ERbeta. In contrast, daidzein was 1000 times more powerful in stimulating ERbeta- over ERalpha-mediated transactivation. Daidzein, in concentrations ranging from 5 nM to 50 microM, did not affect ERbeta-mediated transactivation induced by 1 nM E(2), but it significantly inhibited ERbeta-mediated transactivation induced by 10 nM E(2) at 500 nM. Despite the tremendous difference in sensitivity between the two in vitro systems

  1. Activation of the sigma receptor 1 modulates AMPA receptor-mediated light-evoked excitatory postsynaptic currents in rat retinal ganglion cells.

    Science.gov (United States)

    Liu, Lei-Lei; Deng, Qin-Qin; Weng, Shi-Jun; Yang, Xiong-Li; Zhong, Yong-Mei

    2016-09-22

    Sigma receptor (σR), a unique receptor family, is classified into three subtypes: σR1, σR2 and σR3. It was previously shown that σR1 activation induced by 1μM SKF10047 (SKF) suppressed N-methyl-d-aspartate (NMDA) receptor-mediated responses of rat retinal ganglion cells (GCs) and the suppression was mediated by a distinct Ca(2+)-dependent phospholipase C (PLC)-protein kinase C (PKC) pathway. In the present work, using whole-cell patch-clamp techniques in rat retinal slice preparations, we further demonstrate that SKF of higher dosage (50μM) significantly suppressed AMPA receptor (AMPAR)-mediated light-evoked excitatory postsynaptic currents (L-EPSCs) of retinal ON-type GCs (ON GCs), and the effect was reversed by the σR1 antagonist BD1047, suggesting the involvement of σR1. The SKF (50μM) effect was unlikely due to a change in glutamate release from bipolar cells, as suggested by the unaltered paired-pulse ratio (PPR) of AMPAR-mediated EPSCs of ON GCs. SKF (50μM) did not change L-EPSCs of ON GCs when the G protein inhibitor GDP-β-S or the protein kinase G (PKG) inhibitor KT5823 was intracellularly infused. Calcium imaging further revealed that SKF (50μM) did not change intracellular calcium concentration in GCs and persisted to suppress L-EPSCs when intracellular calcium was chelated by BAPTA. The SKF (50μM) effect was intact when protein kinase A (PKA) and phosphatidylinostiol (PI)-PLC signaling pathways were both blocked. We conclude that the SKF (50μM) effect is Ca(2+)-independent, PKG-dependent, but not involving PKA, PI-PLC pathways. PMID:27373906

  2. Striatal adenosine A{sub 2A} receptor-mediated positron emission tomographic imaging in 6-hydroxydopamine-lesioned rats using [{sup 18}F]-MRS5425

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Abesh Kumar; Lang Lixin; Jacobson, Orit [Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892 (United States); Shinkre, Bidhan [Chemical Biology Unit, Laboratory of Cell Biochemistry and Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 (United States); Ma Ying [Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892 (United States); Niu Gang [Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892 (United States); Department of Radiology and Imaging Sciences, Warren Grant Magnuson Clinical Center, National Institutes of Health, Bethesda, MD 20892 (United States); Trenkle, William C. [Chemical Biology Unit, Laboratory of Cell Biochemistry and Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 (United States); Jacobson, Kenneth A. [Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 (United States); Chen Xiaoyuan [Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892 (United States); Kiesewetter, Dale O., E-mail: dk7k@nih.gov [Laboratory of Molecular Imaging and Nanomedicine, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892 (United States)

    2011-08-15

    Introduction: A{sub 2A} receptors are expressed in the basal ganglia, specifically in striatopallidal GABAergic neurons in the striatum (caudate-putamen). This brain region undergoes degeneration of presynaptic dopamine projections and depletion of dopamine in Parkinson's disease. We developed an {sup 18}F-labeled A{sub 2A} analog radiotracer ([{sup 18}F]-MRS5425) for A{sub 2A} receptor imaging using positron emission tomography (PET). We hypothesized that this tracer could image A{sub 2A} receptor changes in the rat model for Parkinson's disease, which is created following unilateral injection of the monoaminergic toxin 6-hydroxydopamine (6-OHDA) into the substantia nigra. Methods: [{sup 18}F]-MRS5425 was injected intravenously in anesthetized rats, and PET imaging data were collected. Image-derived percentage injected doses per gram (%ID/g) in regions of interest was measured in the striatum of normal rats and in rats unilaterally lesioned with 6-OHDA after intravenous administration of saline (baseline), D{sub 2} agonist quinpirole (1.0 mg/kg) or D{sub 2} antagonist raclopride (6.0 mg/kg). Results: Baseline %ID/g reached a maximum at 90 s and maintained plateau for 3.5 min, and then declined slowly thereafter. In 6-OHDA-lesioned rats, %ID/g was significantly higher in the lesioned side compared to the intact side, and the baseline total %ID/g (data from both hemispheres were combined) was significantly higher compared to quinpirole stimulation starting from 4.5 min until the end of acquisition at 30 min. Raclopride did not produce any change in uptake compared to baseline or between the hemispheres. Conclusion: Thus, increase of A{sub 2A} receptor-mediated uptake of radioactive MRS5425 could be a superior molecular target for Parkinson's imaging.

  3. Alzheimer's therapeutics targeting amyloid beta 1-42 oligomers II: Sigma-2/PGRMC1 receptors mediate Abeta 42 oligomer binding and synaptotoxicity.

    Science.gov (United States)

    Izzo, Nicholas J; Xu, Jinbin; Zeng, Chenbo; Kirk, Molly J; Mozzoni, Kelsie; Silky, Colleen; Rehak, Courtney; Yurko, Raymond; Look, Gary; Rishton, Gilbert; Safferstein, Hank; Cruchaga, Carlos; Goate, Alison; Cahill, Michael A; Arancio, Ottavio; Mach, Robert H; Craven, Rolf; Head, Elizabeth; LeVine, Harry; Spires-Jones, Tara L; Catalano, Susan M

    2014-01-01

    Amyloid beta (Abeta) 1-42 oligomers accumulate in brains of patients with Mild Cognitive Impairment (MCI) and disrupt synaptic plasticity processes that underlie memory formation. Synaptic binding of Abeta oligomers to several putative receptor proteins is reported to inhibit long-term potentiation, affect membrane trafficking and induce reversible spine loss in neurons, leading to impaired cognitive performance and ultimately to anterograde amnesia in the early stages of Alzheimer's disease (AD). We have identified a receptor not previously associated with AD that mediates the binding of Abeta oligomers to neurons, and describe novel therapeutic antagonists of this receptor capable of blocking Abeta toxic effects on synapses in vitro and cognitive deficits in vivo. Knockdown of sigma-2/PGRMC1 (progesterone receptor membrane component 1) protein expression in vitro using siRNA results in a highly correlated reduction in binding of exogenous Abeta oligomers to neurons of more than 90%. Expression of sigma-2/PGRMC1 is upregulated in vitro by treatment with Abeta oligomers, and is dysregulated in Alzheimer's disease patients' brain compared to age-matched, normal individuals. Specific, high affinity small molecule receptor antagonists and antibodies raised against specific regions on this receptor can displace synthetic Abeta oligomer binding to synaptic puncta in vitro and displace endogenous human AD patient oligomers from brain tissue sections in a dose-dependent manner. These receptor antagonists prevent and reverse the effects of Abeta oligomers on membrane trafficking and synapse loss in vitro and cognitive deficits in AD mouse models. These findings suggest sigma-2/PGRMC1 receptors mediate saturable oligomer binding to synaptic puncta on neurons and that brain penetrant, small molecules can displace endogenous and synthetic oligomers and improve cognitive deficits in AD models. We propose that sigma-2/PGRMC1 is a key mediator of the pathological effects of

  4. Alzheimer's therapeutics targeting amyloid beta 1-42 oligomers II: Sigma-2/PGRMC1 receptors mediate Abeta 42 oligomer binding and synaptotoxicity.

    Directory of Open Access Journals (Sweden)

    Nicholas J Izzo

    Full Text Available Amyloid beta (Abeta 1-42 oligomers accumulate in brains of patients with Mild Cognitive Impairment (MCI and disrupt synaptic plasticity processes that underlie memory formation. Synaptic binding of Abeta oligomers to several putative receptor proteins is reported to inhibit long-term potentiation, affect membrane trafficking and induce reversible spine loss in neurons, leading to impaired cognitive performance and ultimately to anterograde amnesia in the early stages of Alzheimer's disease (AD. We have identified a receptor not previously associated with AD that mediates the binding of Abeta oligomers to neurons, and describe novel therapeutic antagonists of this receptor capable of blocking Abeta toxic effects on synapses in vitro and cognitive deficits in vivo. Knockdown of sigma-2/PGRMC1 (progesterone receptor membrane component 1 protein expression in vitro using siRNA results in a highly correlated reduction in binding of exogenous Abeta oligomers to neurons of more than 90%. Expression of sigma-2/PGRMC1 is upregulated in vitro by treatment with Abeta oligomers, and is dysregulated in Alzheimer's disease patients' brain compared to age-matched, normal individuals. Specific, high affinity small molecule receptor antagonists and antibodies raised against specific regions on this receptor can displace synthetic Abeta oligomer binding to synaptic puncta in vitro and displace endogenous human AD patient oligomers from brain tissue sections in a dose-dependent manner. These receptor antagonists prevent and reverse the effects of Abeta oligomers on membrane trafficking and synapse loss in vitro and cognitive deficits in AD mouse models. These findings suggest sigma-2/PGRMC1 receptors mediate saturable oligomer binding to synaptic puncta on neurons and that brain penetrant, small molecules can displace endogenous and synthetic oligomers and improve cognitive deficits in AD models. We propose that sigma-2/PGRMC1 is a key mediator of the pathological

  5. Does ligand-receptor mediated competitive effect or penetrating effect of iRGD peptide when co-administration with iRGD-modified SSL?

    Science.gov (United States)

    Zhang, Wei-Qiang; Yu, Ke-Fu; Zhong, Ting; Luo, Li-Min; Du, Ruo; Ren, Wei; Huang, Dan; Song, Ping; Li, Dan; Zhao, Yang; Wang, Chao; Zhang, Xuan

    2015-12-01

    Ligand-mediated targeting of anticancer therapeutic agents is a useful strategy for improving anti-tumor efficacy. It has been reported that co-administration of a tumor-penetrating peptide iRGD (CRGDK/RGPD/EC) enhances the efficacy of anticancer drugs. Here, we designed an experiment involving co-administration of iRGD-SSL-DOX with free iRGD to B16-F10 tumor bearing mice to examine the action of free iRGD. We also designed an experiment to investigate the location of iRGD-modified SSL when co-administered with free iRGD or free RGD to B16-F10 tumor bearing nude mice. Considering the sequence of iRGD, we selected the GPDC, RGD and CRGDK as targeting ligands to investigate the targeting effect of these peptides compared with iRGD on B16-F10 and MCF-7 cells, with or without enzymatic degradation. Finally, we selected free RGD, free CRGDK and free iRGD as ligand to investigate the inhibitory effect on RGD-, CRGDK- or iRGD-modified SSL on B16-F10 or MCF-7 cells. Our results indicated that iRGD targeting to tumor cells was ligand-receptor mediated involving RGD to αv-integrin receptor and CRGDK to NRP-1 receptor. Being competitive effect, the administration of free iRGD would not be able to further enhance the anti-tumor activity of iRGD-modified SSL. There is no need to co-administrate of free iRGD with the iRGD-modified nanoparticles for further therapeutic benefit.

  6. Striatal adenosine A2A receptor-mediated positron emission tomographic imaging in 6-hydroxydopamine-lesioned rats using [18F]-MRS5425

    International Nuclear Information System (INIS)

    Introduction: A2A receptors are expressed in the basal ganglia, specifically in striatopallidal GABAergic neurons in the striatum (caudate-putamen). This brain region undergoes degeneration of presynaptic dopamine projections and depletion of dopamine in Parkinson's disease. We developed an 18F-labeled A2A analog radiotracer ([18F]-MRS5425) for A2A receptor imaging using positron emission tomography (PET). We hypothesized that this tracer could image A2A receptor changes in the rat model for Parkinson's disease, which is created following unilateral injection of the monoaminergic toxin 6-hydroxydopamine (6-OHDA) into the substantia nigra. Methods: [18F]-MRS5425 was injected intravenously in anesthetized rats, and PET imaging data were collected. Image-derived percentage injected doses per gram (%ID/g) in regions of interest was measured in the striatum of normal rats and in rats unilaterally lesioned with 6-OHDA after intravenous administration of saline (baseline), D2 agonist quinpirole (1.0 mg/kg) or D2 antagonist raclopride (6.0 mg/kg). Results: Baseline %ID/g reached a maximum at 90 s and maintained plateau for 3.5 min, and then declined slowly thereafter. In 6-OHDA-lesioned rats, %ID/g was significantly higher in the lesioned side compared to the intact side, and the baseline total %ID/g (data from both hemispheres were combined) was significantly higher compared to quinpirole stimulation starting from 4.5 min until the end of acquisition at 30 min. Raclopride did not produce any change in uptake compared to baseline or between the hemispheres. Conclusion: Thus, increase of A2A receptor-mediated uptake of radioactive MRS5425 could be a superior molecular target for Parkinson's imaging.

  7. Anxiolytic-like actions of BW 723C86 in the rat Vogel conflict test are 5-HT2B receptor mediated.

    Science.gov (United States)

    Kennett, G A; Trail, B; Bright, F

    1998-12-01

    The 5-HT2B receptor agonist, BW 723C86 (10, 30(mg/kg i.p. 30 min pre-test), increased the number of punishments accepted in a rat Vogel drinking conflict paradigm over 3 min, as did the benzodiazepine anxiolytics, chlordiazepoxide (2.5-10 mg/kg p.o. 1 h pre-test) and alprazolam (0.2-5 mg/kg p.o. 1 h pre-test), but not the 5-HT2C/2B receptor agonist, m-chlorophenylpiperazine (mCPP, 0.3-3 mg/kg i.p) or the 5-HT1A receptor agonist, buspirone (5-20 mg/kg p.o. 1 h pre-test). The effect of BW 723C86 was unlikely to be secondary to enhanced thirst, as BW 723C86 did not increase the time that rats with free access to water spent drinking, nor did it reduce sensitivity to shock in the apparatus. The anti-punishment effect of BW 723C86 was opposed by prior treatment with the 5-HT2/2B receptor antagonist, SB-206553 (10 and 20 mg/kg p.o. 1 h pre-test), and the selective 5-HT2B receptor antagonist, SB-215505 (1 and 3 mg/kg p.o. 1 h pre-test), but not by the selective 5-HT2C receptor antagonist, SB-242084 (5 mg/kg p.o.), or the 5-HT1A receptor antagonist, WAY 100635 (0.1 or 0.3 mg/kg s.c. 30 min pre-test). Thus, the anti-punishment action of BW 723C86 is likely to be 5-HT2B receptor mediated. This is consistent with previous reports that BW 723C86 exhibited anxiolytic-like properties in both the social interaction and Geller-Seifter conflict tests. PMID:9886683

  8. Pressuromodulation at the cell membrane as the basis for small molecule hormone and peptide regulation of cellular and nuclear function.

    Science.gov (United States)

    Sarin, Hemant

    2015-11-26

    Building on recent knowledge that the specificity of the biological interactions of small molecule hydrophiles and lipophiles across microvascular and epithelial barriers, and with cells, can be predicted on the basis of their conserved biophysical properties, and the knowledge that biological peptides are cell membrane impermeant, it has been further discussed herein that cellular, and thus, nuclear function, are primarily regulated by small molecule hormone and peptide/factor interactions at the cell membrane (CM) receptors. The means of regulating cellular, and thus, nuclear function, are the various forms of CM Pressuromodulation that exist, which include Direct CM Receptor-Mediated Stabilizing Pressuromodulation, sub-classified as Direct CM Receptor-Mediated Stabilizing Shift Pressuromodulation (Single, Dual or Tri) or Direct CM Receptor-Mediated Stabilizing Shift Pressuromodulation (Single, Dual or Tri) cum External Cationomodulation (≥3+ → 1+); which are with respect to acute CM receptor-stabilizing effects of small biomolecule hormones, growth factors or cytokines, and also include Indirect CM- or CM Receptor-Mediated Pressuromodulation, sub-classified as Indirect 1ary CM-Mediated Shift Pressuromodulation (Perturbomodulation), Indirect 2ary CM Receptor-Mediated Shift Pressuromodulation (Tri or Quad Receptor Internal Pseudo-Cationomodulation: SS 1+), Indirect 3ary CM Receptor-Mediated Shift Pressuromodulation (Single or Dual Receptor Endocytic External Cationomodulation: 2+) or Indirect (Pseudo) 3ary CM Receptor-Mediated Shift Pressuromodulation (Receptor Endocytic Hydroxylocarbonyloetheroylomodulation: 0), which are with respect to sub-acute CM receptor-stabilizing effects of small biomolecules, growth factors or cytokines. As a generalization, all forms of CM pressuromodulation decrease CM and nuclear membrane (NM) compliance (whole cell compliance), due to pressuromodulation of the intracellular microtubule network and increases the exocytosis of pre

  9. Metabotropic Regulation of Extrasynaptic GABAA Receptors

    Directory of Open Access Journals (Sweden)

    William Martin Connelly

    2013-10-01

    Full Text Available A large body of work now shows the importance of GABAA receptor-mediated tonic inhibition in regulating CNS function. However, outside of pathological conditions, there is relatively little evidence that the magnitude of tonic inhibition is itself under regulation. Here we review the mechanisms by which tonic inhibition is known to be modulated, and outline the potential behavioural consequences of this modulation. Specifically, we address the ability of protein kinase A and C to phosphorylate the extrasynaptic receptors responsible for the tonic GABAA current, and how G-protein coupled receptors can regulate tonic inhibition through these effectors. We then speculate about the possible functional consequences of regulating the magnitude of the tonic GABAA current.

  10. 甲状腺激素非经典核受体作用途径的研究进展%Progress in the Study of Non-classical Nuclear Receptor Mediated Mechanism of Thyroid Hormone

    Institute of Scientific and Technical Information of China (English)

    王浩华

    2012-01-01

    甲状腺激素是维持机体功能活动的基础性激素,在机体产热、新陈代谢、组织分化和器官发育等方面具有重要的调节作用,一般认为甲状腺激素结合靶细胞核内甲状腺激素受体,启动特异性甲状腺激素应答基因的转录表达,发挥生物学效应.近年来研究发现,某些甲状腺激素引起的生物反应迅速,而且不受基因转录与翻译相关抑制剂的影响,提示甲状腺激素存在非经典核受体作用途径,甲状腺激素介导的非经典核受体作用途径在心肌细胞、人神经胶质细胞、人成纤维细胞和成骨细胞等已被证实.%Thyroid hormone( TH )is a basal hormone which maintains the body's functional activity and has a critical role in energy utilization, metabolism, tissue differentiation and organ growth. It's generally considered that most thyroid hormone effects are mediated by direct transcriptional effects of thyroid hormone bound to nuclear thyroid hormone receptors( TRs ). Recently, a new mechanism of thyroid hormone action is identified which is very rapid and not affected by RNA and protein synthesis inhibitor, indicating a non-classical nuclear receptor mediated action. Besides,the non-classical nuclear receptor mediated action of thyroid hormone has been verified in cardiomyocyte, human glioma,human fibroblasts, osteoblast and so on.

  11. Acute and chronic effects of citalopram on postsynaptic 5-hydroxytryptamine(1A) receptor-mediated feedback : a microdialysis study in the amygdala

    NARCIS (Netherlands)

    Bosker, FJ; Cremers, TIFH; Jongsma, ME; Westerink, BHC; Wikstrom, VH; den Boer, JA

    2001-01-01

    Microdialysis was used to assess the involvement of postsynaptic 5-hydroxytryptamine(1A) (5-HT1A) receptors in the regulation of extracellular 5-HT in the amygdala. Local infusion of the 5-HT1A receptor agonist flesinoxan (0.3, 1, 3 muM) for 30 min into the amygdala maximally decreased 5-HT to 50% o

  12. Salmonella enterica Serovar Typhi Modulates Cell Surface Expression of Its Receptor, the Cystic Fibrosis Transmembrane Conductance Regulator, on the Intestinal Epithelium

    OpenAIRE

    Lyczak, Jeffrey B.; Pier, Gerald B.

    2002-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) protein is an epithelial receptor mediating the translocation of Salmonella enterica serovar Typhi to the gastric submucosa. Since the level of cell surface CFTR is directly related to the efficiency of serovar Typhi translocation, the goal of this study was to measure CFTR expression by the intestinal epithelium during infection. CFTR protein initially present in the epithelial cell cytoplasm was rapidly trafficked to the plasma ...

  13. Kinin B1 receptors mediate depression-like behavior response in stressed mice treated with systemic E. coli lipopolysaccharide

    OpenAIRE

    Campos Maria M; Siqueira Jarbas M; Figueiredo Claudia P; Dornelles Fabiana N; Maciel Izaque S; Viana Alice F; Calixto João B

    2010-01-01

    Abstract Background Kinin B1 receptors are inducible molecules up-regulated after inflammatory stimuli. This study evaluated the relevance of kinin B1 receptors in a mouse depression behavior model. Methods Mice were exposed to a 5-min swimming session, and 30 min later they were injected with E. coli lipopolysaccharide (LPS). Depression-like behavior was assessed by determining immobility time in a tail suspension test. Different brain structures were collected for molecular and immunohistoc...

  14. Control of Toll-like receptor-mediated T cell-independent type 1 antibody responses by the inducible nuclear protein IκB-ζ.

    Science.gov (United States)

    Hanihara-Tatsuzawa, Fumito; Miura, Hanae; Kobayashi, Shuhei; Isagawa, Takayuki; Okuma, Atsushi; Manabe, Ichiro; MaruYama, Takashi

    2014-11-01

    Antibody responses have been classified as being either T cell-dependent or T cell-independent (TI). TI antibody responses are further classified as being either type 1 (TI-1) or type 2 (TI-2), depending on their requirement for B cell-mediated antigen receptor signaling. Although the mechanistic basis of antibody responses has been studied extensively, it remains unclear whether different antibody responses share similarities in their transcriptional regulation. Here, we show that mice deficient in IκB-ζ, specifically in their B cells, have impaired TI-1 antibody responses but normal T cell-dependent and TI-2 antibody responses. The absence of IκB-ζ in B cells also impaired proliferation triggered by Toll-like receptor (TLR) activation, plasma cell differentiation, and class switch recombination (CSR). Mechanistically, IκB-ζ-deficient B cells could not induce TLR-mediated induction of activation-induced cytidine deaminase (AID), a class-switch DNA recombinase. Retroviral transduction of AID in IκB-ζ-deficient B cells restored CSR activity. Furthermore, acetylation of histone H3 in the vicinity of the transcription start site of the gene that encodes AID was reduced in IκB-ζ-deficient B cells relative to IκB-ζ-expressing B cells. These results indicate that IκB-ζ regulates TLR-mediated CSR by inducing AID. Moreover, IκB-ζ defines differences in the transcriptional regulation of different antibody responses. PMID:25124037

  15. Differential effects of amisulpride and haloperidol on dopamine D2 receptor-mediated signaling in SH-SY5Y cells.

    Science.gov (United States)

    Park, Sung Woo; Seo, Mi Kyoung; Cho, Hye Yeon; Lee, Jung Goo; Lee, Bong Ju; Seol, Wongi; Kim, Young Hoon

    2011-09-01

    Dopamine D(2) receptors (D(2)R) are the primary target of antipsychotic drugs and have been shown to regulate Akt/glycogen synthase kinase-3β (GSK-3β) signaling through scaffolding protein β-arrestin 2. Amisulpride, an atypical antipsychotic drug, and haloperidol, a typical antipsychotic drug, are both potent D(2)R antagonists, but their therapeutic effects differ. In the present study, we compared the effects of amisulpride and haloperidol on the β-arrestin 2-mediated Akt/GSK-3β pathway in SH-SY5Y cells. To determine whether these drugs affected neuronal morphology in SH-SY5Y cells, we investigated the effects of amisulpride and haloperidol on neurite outgrowth using immunostaining. We examined the effects of these drugs on Akt and GSK-3β and its well-known downstream regulators, cAMP response element-binding protein (CREB), brain-derived neurotrophic factor (BDNF), and Bcl-2 levels using Western blot analysis. Amisulpride, but not haloperidol, was found to enhance neurite outgrowth. Small interfering RNA (siRNA) for β-arrestin 2 knockdown blocked the increase in amisulpride-induced neurite outgrowth. Furthermore, amisulpride increased the levels of Akt and GSK-3β phosphorylation, while haloperidol had no effect. The elevation of Akt phosphorylation induced by amisulpride was reduced by β-arrestin 2 siRNA. Moreover, amisulpride effectively increased the levels of phospho-CREB, BDNF, and Bcl-2. However, haloperidol had no effect on the levels of these proteins. Additionally, wortmannin, a phosphatidylinositol 3-kinase (PI3 K) inhibitor, blocked the stimulatory effect of amisulpride on phosphorylated Akt. Together, these results suggest that regulation of the β-arrestin 2-dependent pathway via blockade of the D(2)R in SH-SY5Y cells is one mechanism underlying the neuroprotective effect of amisulpride, but not haloperidol.

  16. T-cell independent, B-cell receptor-mediated induction of telomerase activity differs among IGHV mutation-based subgroups of chronic lymphocytic leukemia patients

    OpenAIRE

    Damle, Rajendra N.; Temburni, Sonal; Banapour, Taraneh; Paul, Santanu; Mongini, Patricia K. A.; Allen, Steven L.; Kolitz, Jonathan E.; Rai, Kanti R; Chiorazzi, Nicholas

    2012-01-01

    Although B-cell chronic lymphocytic leukemia (B-CLL) clones with unmutated IGHV genes (U-CLL) exhibit greater telomerase activity than those with mutated IGHV genes (M-CLL), the extent to which B-cell receptor (BCR) triggering contributes to telomerase up-regulation is not known. Therefore, we studied the effect of BCR stimulation on modulating telomerase activity. The multivalent BCR ligand, dextran conjugated anti-μ mAb HB57 (HB57-dex), increased telomerase activity and promoted cell surviv...

  17. T cell homeostasis requires G protein-coupled receptor-mediated access to trophic signals that promote growth and inhibit chemotaxis

    OpenAIRE

    Cinalli, Ryan M.; Herman, Catherine E.; Lew, Brian O.; Wieman, Heather L.; Thompson, Craig B.; Rathmell, Jeffrey C.

    2005-01-01

    Signals that regulate T cell homeostasis are not fully understood. G protein-coupled receptors (GPCR), such as the chemokine receptors, may affect homeostasis by direct signaling or by guiding T cell migration to distinct location-restricted signals. Here, we show that blockade of Gαi-associated GPCR signaling by treatment with pertussis toxin led to T cell atrophy and shortened life-span in T cell-replete hosts and prevented T cell homeostatic growth and proliferation in T cell-deficient hos...

  18. GABAA Receptor-Mediated Bidirectional Control of Synaptic Activity, Intracellular Ca2+, Cerebral Blood Flow, and Oxygen Consumption in Mouse Somatosensory Cortex In Vivo

    DEFF Research Database (Denmark)

    Jessen, Sanne Barsballe; Brazhe, Alexey; Lind, Barbara Lykke;

    2015-01-01

    concentrations of THIP suppressed ΔCBF and ΔCMRO2 at high stimulation frequencies. Zolpidem had similar but less-pronounced effects, with similar dependence on drug concentration and stimulation frequency. Our present findings suggest that slight increases in both synaptic and extrasynaptic GABAAR activity might......Neural activity regulates local increases in cerebral blood flow (ΔCBF) and the cortical metabolic rate of oxygen (ΔCMRO2) that constitutes the basis of BOLD functional neuroimaging signals. Glutamate signaling plays a key role in brain vascular and metabolic control; however, the modulatory effect...

  19. Rap2B-Dependent Stimulation of Phospholipase C-ɛ by Epidermal Growth Factor Receptor Mediated by c-Src Phosphorylation of RasGRP3

    OpenAIRE

    Stope, Matthias B.; vom Dorp, Frank; Szatkowski, Daniel; Böhm, Anja; Keiper, Melanie; Nolte, Jan; Oude Weernink, Paschal A; Rosskopf, Dieter; Evellin, Sandrine; Jakobs, Karl H; Schmidt, Martina

    2004-01-01

    Receptor tyrosine kinase regulation of phospholipase C-ɛ (PLC-ɛ), which is under the control of Ras-like and Rho GTPases, was studied with HEK-293 cells endogenously expressing PLC-coupled epidermal growth factor (EGF) receptors. PLC and Ca2+ signaling by the EGF receptor, which activated both PLC-γ1 and PLC-ɛ, was specifically suppressed by inactivation of Ras-related GTPases with clostridial toxins and expression of dominant-negative Rap2B. EGF induced rapid and sustained GTP loading of Rap...

  20. Novel positive regulatory role for the SPL6 transcription factor in the N TIR-NB-LRR receptor-mediated plant innate immunity.

    Directory of Open Access Journals (Sweden)

    Meenu S Padmanabhan

    2013-03-01

    Full Text Available Following the recognition of pathogen-encoded effectors, plant TIR-NB-LRR immune receptors induce defense signaling by a largely unknown mechanism. We identify a novel and conserved role for the SQUAMOSA PROMOTER BINDING PROTEIN (SBP-domain transcription factor SPL6 in enabling the activation of the defense transcriptome following its association with a nuclear-localized immune receptor. During an active immune response, the Nicotiana TIR-NB-LRR N immune receptor associates with NbSPL6 within distinct nuclear compartments. NbSPL6 is essential for the N-mediated resistance to Tobacco mosaic virus. Similarly, the presumed Arabidopsis ortholog AtSPL6 is required for the resistance mediated by the TIR-NB-LRR RPS4 against Pseudomonas syringae carrying the avrRps4 effector. Transcriptome analysis indicates that AtSPL6 positively regulates a subset of defense genes. A pathogen-activated nuclear-localized TIR-NB-LRR like N can therefore regulate defense genes through SPL6 in a mechanism analogous to the induction of MHC genes by mammalian immune receptors like CIITA and NLRC5.

  1. Wild-type and specific mutant androgen receptor mediates transcription via 17β-estradiol in sex hormone-sensitive cancer cells.

    Science.gov (United States)

    Susa, Takao; Ikaga, Reina; Kajitani, Takashi; Iizuka, Masayoshi; Okinaga, Hiroko; Tamamori-Adachi, Mimi; Okazaki, Tomoki

    2015-07-01

    We previously encountered regulatory processes wherein dihydrotestosterone (DHT) exerted its inhibitory effect on parathyroid hormone-related protein (PTHrP) gene repression through the estrogen receptor (ER)α, but not the androgen receptor (AR), in breast cancer MCF-7 cells. Here, we investigated whether such aberrant ligand-nuclear receptor (NR) interaction is present in prostate cancer LNCaP cells. First, we confirmed that LNCaP cells expressed large amounts of AR at negligible levels of ERα/β or progesterone receptor. Both suppression of PTHrP and activation of prostate-specific antigen genes were observed after independent administration of 17β-estradiol (E2), DHT, or R5020. Consistent with the notion that the LNCaP AR lost its ligand specificity due to a mutation (Thr-Ala877), experiments with siRNA targeting the respective NR revealed that the AR monopolized the role of the mediator of shared hormone-dependent regulation, which was invariably associated with nuclear translocation of this mutant AR. Microarray analysis of gene regulation by DHT, E2, or R5020 disclosed that more than half of the genes downstream of the AR (Thr-Ala877) overlapped in the LNCaP cells. Of particular interest, we realized that the AR (wild-type [wt]) and AR (Thr-Ala877) were equally responsible for the E2-AR interactions. Fluorescence microscopy experiments demonstrated that both EGFP-AR (wt) and EGFP-AR (Thr-Ala877) were exclusively localized within the nucleus after E2 or DHT treatment. Furthermore, reporter assays revealed that some other cancer cells exhibited aberrant E2-AR (wt) signaling similar to that in the LNCaP cells. We herein postulate the presence of entangled interactions between wt AR and E2 in certain hormone-sensitive cancer cells.

  2. Folate receptor-mediated boron-10 containing carbon nanoparticles as potential delivery vehicles for boron neutron capture therapy of nonfunctional pituitary adenomas.

    Science.gov (United States)

    Dai, Congxin; Cai, Feng; Hwang, Kuo Chu; Zhou, Yongmao; Zhang, Zizhu; Liu, Xiaohai; Ma, Sihai; Yang, Yakun; Yao, Yong; Feng, Ming; Bao, Xinjie; Li, Guilin; Wei, Junji; Jiao, Yonghui; Wei, Zhenqing; Ma, Wenbin; Wang, Renzhi

    2013-02-01

    Invasive nonfunctional pituitary adenomas (NFPAs) are difficult to completely resect and often develop tumor recurrence after initial surgery. Currently, no medications are clinically effective in the control of NFPA. Although radiation therapy and radiosurgery are useful to prevent tumor regrowth, they are frequently withheld because of severe complications. Boron neutron capture therapy (BNCT) is a binary radiotherapy that selectively and maximally damages tumor cells without harming the surrounding normal tissue. Folate receptor (FR)-targeted boron-10 containing carbon nanoparticles is a novel boron delivery agent that can be selectively taken up by FR-expressing cells via FR-mediated endocytosis. In this study, FR-targeted boron-10 containing carbon nanoparticles were selectively taken up by NFPAs cells expressing FR but not other types of non-FR expressing pituitary adenomas. After incubation with boron-10 containing carbon nanoparticles and following irradiation with thermal neutrons, the cell viability of NFPAs was significantly decreased, while apoptotic cells were simultaneously increased. However, cells administered the same dose of FR-targeted boron-10 containing carbon nanoparticles without neutron irradiation or received the same neutron irradiation alone did not show significant decrease in cell viability or increase in apoptotic cells. The expression of Bcl-2 was down-regulated and the expression of Bax was up-regulated in NFPAs after treatment with FR-mediated BNCT. In conclusion, FR-targeted boron-10 containing carbon nanoparticles may be an ideal delivery system of boron to NFPAs cells for BNCT. Furthermore, our study also provides a novel insight into therapeutic strategies for invasive NFPA refractory to conventional therapy, while exploring these new applications of BNCT for tumors, especially benign tumors.

  3. Human GRK4γ142V Variant Promotes Angiotensin II Type I Receptor-Mediated Hypertension via Renal Histone Deacetylase Type 1 Inhibition.

    Science.gov (United States)

    Wang, Zheng; Zeng, Chunyu; Villar, Van Anthony M; Chen, Shi-You; Konkalmatt, Prasad; Wang, Xiaoyan; Asico, Laureano D; Jones, John E; Yang, Yu; Sanada, Hironobu; Felder, Robin A; Eisner, Gilbert M; Weir, Matthew R; Armando, Ines; Jose, Pedro A

    2016-02-01

    The influence of a single gene on the pathogenesis of essential hypertension may be difficult to ascertain, unless the gene interacts with other genes that are germane to blood pressure regulation. G-protein-coupled receptor kinase type 4 (GRK4) is one such gene. We have reported that the expression of its variant hGRK4γ(142V) in mice results in hypertension because of impaired dopamine D1 receptor. Signaling through dopamine D1 receptor and angiotensin II type I receptor (AT1R) reciprocally modulates renal sodium excretion and blood pressure. Here, we demonstrate the ability of the hGRK4γ(142V) to increase the expression and activity of the AT1R. We show that hGRK4γ(142V) phosphorylates histone deacetylase type 1 and promotes its nuclear export to the cytoplasm, resulting in increased AT1R expression and greater pressor response to angiotensin II. AT1R blockade and the deletion of the Agtr1a gene normalize the hypertension in hGRK4γ(142V) mice. These findings illustrate the unique role of GRK4 by targeting receptors with opposite physiological activity for the same goal of maintaining blood pressure homeostasis, and thus making the GRK4 a relevant therapeutic target to control blood pressure.

  4. Unimpaired Autoreactive T-Cell Traffic Within the Central Nervous System During Tumor Necrosis Factor Receptor-Mediated inhibition of Experimental Autoimmune Encephalomyelitis

    Science.gov (United States)

    Korner, Heinrich; Goodsall, Anna L.; Lemckert, Frances A.; Scallon, Bernard J.; Ghrayeb, John; Ford, Andrew L.; Sedgwick, Jonathon D.

    1995-11-01

    The critical role of tumor necrosis factor (TNF) as a mediator in autoimmune inflammatory processes is evident from in vivo studies with TNF-blocking agents. However, the mechanisms by which TNF, and possibly also its homologue lymphotoxin α, contributes to development of pathology in rheumatoid arthritis and Crohn disease and in animal models like experimental autoimmune encephalomyelitis is unclear. Possibilities include regulation of vascular adhesion molecules enabling leukocyte movement into tissues or direct cytokine-mediated effector functions such as mediation of tissue damage. Here we show that administration of a TNF receptor (55 kDa)-IgG fusion protein prevented clinical signs of actively induced experimental autoimmune encephalomyelitis. Significantly, the total number of CD4^+ T lymphocytes isolated from the central nervous system of clinically healthy treated versus diseased control animals was comparable. By using a CD45 congenic model of passively transferred experimental autoimmune encephalomyelitis to enable tracking of myelin basic protein-specific effector T lymphocytes, prevention of clinical signs of disease was again demonstrated in treated animals but without quantitative or qualitative impediment to the movement of autoreactive T lymphocytes to and within the central nervous system. Thus, despite the uninterrupted movement of specific T lymphocytes into the target tissue, subsequent disease development was blocked. This provides compelling evidence for a direct effector role of TNF/lymphotoxin α in autoimmune tissue damage.

  5. Basolateral P2X receptors mediate inhibition of NaCl transport in mouse medullary thick ascending limb (mTAL)

    DEFF Research Database (Denmark)

    Marques, Rita D; de Bruijn, Pauline I.A.; Sørensen, Mads Vaarby;

    2012-01-01

    Extracellular nucleotides regulate epithelial transport via luminal and basolateral P2 receptors. Renal epithelia express multiple P2 receptors, which mediate significant inhibition of solute absorption. Recently, we identified several P2 receptors in the medullary thick ascending limb (m......-stimulated mTALs transported at a rate of 1197 ± 104 µA/cm(2) (n=10), which was completely blockable with luminal furosemide (100 µM). Basolateral ATP (100 µM) acutely (1 minute) and reversibly reduced the absorptive I'(sc). After 2 minutes the reduction amounted to 24.4 ± 4.0% (n=10). The non-selective P2...... the ATP-induced inhibition of transport was reduced. A comprehensive molecular search identified P2X(4), P2X(5) and P2X(1) receptor subunit mRNA in isolated mouse mTALs. These data define that basolateral ATP exerts a significant inhibition of Na(+) absorption in mouse mTAL. Pharmacological, molecular...

  6. Activation of EphA receptors mediates the recruitment of the adaptor protein Slap, contributing to the downregulation of N-methyl-D-aspartate receptors.

    Science.gov (United States)

    Semerdjieva, Sophia; Abdul-Razak, Hayder H; Salim, Sharifah S; Yáñez-Muñoz, Rafael J; Chen, Philip E; Tarabykin, Victor; Alifragis, Pavlos

    2013-04-01

    Regulation of the activity of N-methyl-d-aspartate receptors (NMDARs) at glutamatergic synapses is essential for certain forms of synaptic plasticity underlying learning and memory and is also associated with neurotoxicity and neurodegenerative diseases. In this report, we investigate the role of Src-like adaptor protein (Slap) in NMDA receptor signaling. We present data showing that in dissociated neuronal cultures, activation of ephrin (Eph) receptors by chimeric preclustered eph-Fc ligands leads to recruitment of Slap and NMDA receptors at the sites of Eph receptor activation. Interestingly, our data suggest that prolonged activation of EphA receptors is as efficient in recruiting Slap and NMDA receptors as prolonged activation of EphB receptors. Using established heterologous systems, we examined whether Slap is an integral part of NMDA receptor signaling. Our results showed that Slap does not alter baseline activity of NMDA receptors and does not affect Src-dependent potentiation of NMDA receptor currents in Xenopus oocytes. We also demonstrate that Slap reduces excitotoxic cell death triggered by activation of NMDARs in HEK293 cells. Finally, we present evidence showing reduced levels of NMDA receptors in the presence of Slap occurring in an activity-dependent manner, suggesting that Slap is part of a mechanism that homeostatically modulates the levels of NMDA receptors.

  7. Central CRTH2, a second prostaglandin D2 receptor, mediates emotional impairment in the lipopolysaccharide and tumor-induced sickness behavior model.

    Science.gov (United States)

    Haba, Ryota; Shintani, Norihito; Onaka, Yusuke; Kanoh, Takuya; Wang, Hyper; Takenaga, Risa; Hayata, Atsuko; Hirai, Hiroyuki; Nagata, Kin-ya; Nakamura, Masataka; Kasai, Atsushi; Hashimoto, Ryota; Nagayasu, Kazuki; Nakazawa, Takanobu; Hashimoto, Hitoshi; Baba, Akemichi

    2014-02-12

    Chemoattractant receptor-homologous molecule expressed on T helper type 2 cells (CRTH2) is a second prostaglandin D2 receptor involved in mediating the allergic response; however, its central function is not yet known. Here, we demonstrate that central CRTH2 mediates emotional impairment. Lipopolysaccharide (LPS)-induced decreases in social interaction and novel exploratory behavior were observed in wild-type (CRTH2(+/+)) mice but not CRTH2-deficient (CRTH2(-/-)) mice, but both genotypes showed hypolocomotion and anorexia following LPS injection. Tumor (colon 26) inoculation, a more pathologically relevant model, induced decreases in social interaction and novel exploratory behavior in CRTH2(+/+), but not CRTH2(-/-) mice. In addition, the CRTH2 antagonists including clinically available ramatroban reversed impaired social interaction and novel exploratory behavior after either LPS or tumor inoculation in CRTH2(+/+) mice. Finally, LPS-induced c-Fos expression in the hypothalamic paraventricular nucleus (PVN) and central amygdala (CeA) was selectively abolished in CRTH2(-/-) mice. These results show that CRTH2 participates in LPS-induced emotional changes and activation in the PVN and CeA. Our study provides the first evidence that central CRTH2 regulates specific emotional behaviors, and that CRTH2 antagonism has potential as a therapeutic target for behavioral symptoms associated with tumors and infectious diseases.

  8. Ligustrazine attenuates oxidative stress-induced activation of hepatic stellate cells by interrupting platelet-derived growth factor-β receptor-mediated ERK and p38 pathways

    International Nuclear Information System (INIS)

    Hepatic fibrosis represents a frequent event following chronic insult to trigger wound healing reactions with accumulation of extracellular matrix (ECM) in the liver. Activation of hepatic stellate cells (HSCs) is the pivotal event during liver fibrogenesis. Compelling evidence indicates that oxidative stress is concomitant with liver fibrosis irrespective of the underlying etiology. Natural antioxidant ligustrazine exhibits potent antifibrotic activities, but the mechanisms are poorly understood. Our studies were to investigate the ligustrazine effects on HSC activation stimulated by hydrogen peroxide (H2O2), an in vitro model mimicking the oxidative stress in liver fibrogenesis, and to elucidate the possible mechanisms. Our results demonstrated that H2O2 at 5 μM significantly stimulated HSC proliferation and expression of marker genes of HSC activation; whereas ligustrazine dose-dependently suppressed proliferation and induced apoptosis in H2O2-activated HSCs, and attenuated expression of fibrotic marker genes. Mechanistic investigations revealed that ligustrazine reduced platelet-derived growth factor-β receptor (PDGF-βR) expression and blocked the phosphorylation of extracellular regulated protein kinase (ERK) and p38 kinase, two downstream effectors of PDGF-βR. Further molecular evidence suggested that ligustrazine interruption of ERK and p38 pathways was dependent on the blockade of PDGF-βR and might be involved in ligustrazine reduction of fibrotic marker gene expression under H2O2 stimulation. Furthermore, ligustrazine modulated some proteins critical for HSC activation and ECM homeostasis in H2O2-stimulated HSCs. These data collectively indicated that ligustrazine could attenuate HSC activation caused by oxidative stress, providing novel insights into ligustrazine as a therapeutic option for hepatic fibrosis. Highlights: ► Ligustrazine inhibits oxidative stress-induced HSC activation. ► Ligustrazine reduces fibrotic marker genes in HSCs under

  9. T-cell independent, B-cell receptor-mediated induction of telomerase activity differs among IGHV mutation-based subgroups of chronic lymphocytic leukemia patients.

    Science.gov (United States)

    Damle, Rajendra N; Temburni, Sonal; Banapour, Taraneh; Paul, Santanu; Mongini, Patricia K A; Allen, Steven L; Kolitz, Jonathan E; Rai, Kanti R; Chiorazzi, Nicholas

    2012-09-20

    Although B-cell chronic lymphocytic leukemia (B-CLL) clones with unmutated IGHV genes (U-CLL) exhibit greater telomerase activity than those with mutated IGHV genes (M-CLL), the extent to which B-cell receptor (BCR) triggering contributes to telomerase up-regulation is not known. Therefore, we studied the effect of BCR stimulation on modulating telomerase activity. The multivalent BCR ligand, dextran conjugated anti-μ mAb HB57 (HB57-dex), increased telomerase activity and promoted cell survival and proliferation preferentially in U-CLL cases, whereas the PI3K/Akt inhibitor LY294002 blocked HB57-dex induced telomerase activation. Although both U-CLL and M-CLL clones exhibited similar membrane proximal signaling responses to HB57-dex, telomerase activity and cell proliferation, when inducible in M-CLL, differed. B-CLL cells stimulated using bivalent F(ab')(2) -goat anti-μ antibody (goat anti-μ) exhibited higher membrane proximal response in U-CLL than M-CLL cells, whereas telomerase activity, cell survival, and proliferation were induced to lower levels than those induced by HB57-dex. In normal B lymphocytes, HB57-dex induced less protein phosphorylation but more cell proliferation and survival than goat anti-μ. Although both anti-BCR stimuli induced comparable telomerase activity, normal CD5(+) B cells preferentially exhibited higher hTERT positivity than their CD5(-) counterparts. These findings provide an understanding of how BCR-mediated signals impact telomerase modulation in IGHV mutation-based subgroups of B-CLL and normal B cells. PMID:22875913

  10. Dopamine D2 receptor-mediated Akt/PKB signalling: initiation by the D2S receptor and role in quinpirole-induced behavioural activation.

    Science.gov (United States)

    Chen, Han-Ting; Ruan, Nan-Yu; Chen, Jin-Chung; Lin, Tzu-Yung

    2012-09-24

    The short and long isoforms of the dopamine D2 receptor (D2S and D2L respectively) are highly expressed in the striatum. Functional D2 receptors activate an intracellular signalling pathway that includes a cAMP-independent route involving Akt/GSK3 (glycogen synthase kinase 3). To investigate the Akt/GSK3 response to the seldom-studied D2S receptor, we established a rat D2S receptor-expressing cell line [HEK (human embryonic kidney)-293/rD2S]. We found that in HEK-293/rD2S cells, the D2/D3 agonists bromocriptine and quinpirole significantly induced Akt and GSK3 phosphorylation, as well as ERK1/2 (extracellular-signal-regulated kinase 1/2) activation. The D2S receptor-induced Akt signals were profoundly inhibited by the internalization blockers monodansyl cadaverine and concanavalin A. Activation of the D2S receptor in HEK-293/rD2S cells appeared to trigger Akt/phospho-Akt translocation to the cell membrane. In addition to our cell culture experiments, we studied D2 receptor-dependent Akt in vivo by systemic administration of the D2/D3 agonist quinpirole. The results show that quinpirole evoked Akt-Ser473 phosphorylation in the ventral striatum. Furthermore, intra-accumbens administration of wortmannin, a PI3K (phosphoinositide 3-kinase) inhibitor, significantly suppressed the quinpirole-evoked behavioural activation. Overall, we demonstrate that activation of the dopamine D2S receptor stimulates Akt/GSK3 signalling. In addition, in vivo Akt activity in the ventral striatum appears to play an important role in systemic D2/D3 agonist-induced behavioural activation.

  11. Dopamine D2 receptor-mediated Akt/PKB signalling: initiation by the D2S receptor and role in quinpirole-induced behavioural activation

    Directory of Open Access Journals (Sweden)

    Jin‑Chung Chen

    2012-09-01

    Full Text Available The short and long isoforms of the dopamine D2 receptor (D2S and D2L respectively are highly expressed in the striatum. Functional D2 receptors activate an intracellular signalling pathway that includes a cAMP-independent route involving Akt/GSK3 (glycogen synthase kinase 3. To investigate the Akt/GSK3 response to the seldom-studied D2S receptor, we established a rat D2S receptor-expressing cell line [HEK (human embryonic kidney-293/rD2S]. We found that in HEK-293/rD2S cells, the D2/D3 agonists bromocriptine and quinpirole significantly induced Akt and GSK3 phosphorylation, as well as ERK1/2 (extracellular-signal-regulated kinase 1/2 activation. The D2S receptor-induced Akt signals were profoundly inhibited by the internalization blockers monodansyl cadaverine and concanavalin A. Activation of the D2S receptor in HEK-293/rD2S cells appeared to trigger Akt/phospho-Akt translocation to the cell membrane. In addition to our cell culture experiments, we studied D2 receptor-dependent Akt in vivo by systemic administration of the D2/D3 agonist quinpirole. The results show that quinpirole evoked Akt-Ser473 phosphorylation in the ventral striatum. Furthermore, intra-accumbens administration of wortmannin, a PI3K (phosphoinositide 3-kinase inhibitor, significantly suppressed the quinpirole-evoked behavioural activation. Overall, we demonstrate that activation of the dopamine D2S receptor stimulates Akt/GSK3 signalling. In addition, in vivo Akt activity in the ventral striatum appears to play an important role in systemic D2/D3 agonist-induced behavioural activation.

  12. Flavonoids activate pregnane × receptor-mediated CYP3A4 gene expression by inhibiting cyclin-dependent kinases in HepG2 liver carcinoma cells

    Directory of Open Access Journals (Sweden)

    Wu Jing

    2010-06-01

    Full Text Available Abstract Background The expression of the drug-metabolizing enzyme cytochrome P450 3A4 (CYP3A4 is regulated by the pregnane × receptor (PXR, which is modulated by numerous signaling pathways, including the cyclin-dependent kinase (Cdk pathway. Flavonoids, commonly consumed by humans as dietary constituents, have been shown to modulate various signaling pathways (e.g., inhibiting Cdks. Flavonoids have also been shown to induce CYPs expression, but the underlying mechanism of action is unknown. Here, we report the mechanism responsible for flavonoid-mediated PXR activation and CYP expression. Results In a cell-based screen designed to identify compounds that activate PXR-mediated CYP3A4 gene expression in HepG2 human carcinoma cells, we identified several flavonoids, such as luteolin and apigenin, as PXR activators. The flavonoids did not directly bind to PXR, suggesting that an alternative mechanism may be responsible for flavonoid-mediated PXR activation. Consistent with the Cdk5-inhibitory effect of flavonoids, Cdk5 and p35 (a non-cyclin regulatory subunit required to activate Cdk5 were expressed in HepG2. The activation of Cdk5 attenuated PXR-mediated CYP3A4 expression whereas its downregulation enhanced it. The Cdk5-mediated downregulation of CYP3A4 promoter activity was restored by flavonoids, suggesting that flavonoids activate PXR by inactivating Cdk5. In vitro kinase assays showed that Cdk5 directly phosphorylates PXR. The Cdk kinase profiling assay showed that apigenin inhibits multiple Cdks, suggesting that several Cdks may be involved in activation of PXR by flavonoids. Conclusions Our results for the first time link the stimulatory effect of flavonoids on CYP expression to their inhibitory effect on Cdks, through a PXR-mediated mechanism. These results may have important implications on the pharmacokinetics of drugs co-administered with herbal remedy and herbal-drug interactions.

  13. The CRH-R₁ receptor mediates luteinizing hormone, prolactin, corticosterone and progesterone secretion induced by restraint stress in estrogen-primed rats.

    Science.gov (United States)

    Traslaviña, Guillermo A Ariza; Franci, Celso Rodrigues

    2011-11-01

    Acute stress has been shown to modify hypothalamus-pituitary-gonadal (HPG) axis activity. Corticotropin-releasing hormone (CRH), the principal regulator of the hypothalamus-pituitary-adrenal (HPA) axis, has been implicated as a mediator of stress-induced effects on the reproductive axis. The role of the specific CRH receptor subtypes in this response is not completely understood. In the current study, we investigated the role of the CRH-R(1) receptor on luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), progesterone (P) and corticosterone (CT) secretion in stress-induced responses under the influence of estrogen (E(2)). Estrogen-primed ovariectomized rats (estradiol cypionate, 10 μg sc) received an i.v. administration of antalarmin (0.1 or 1mg/kg), a selective CRH-R(1) antagonist, or vehicle before restraint stress for 40 min. Seven blood samples were collected from two experimental groups (one from 10:00 h to 14:00 h and the other from 10:00 h to 18:00 h). An increase of plasma LH induced by restraint acute-stress was followed by alteration of the secretion pattern in the estrogen-induced afternoon surge. In a similar manner, we observed a suppression of the afternoon surge in plasma FSH, a delay of E(2)-induced PRL secretion, and an increase in plasma P and CT. Antalarmin attenuated stress-induce LH increase, decreased CT and P secretion and blocked the stress effects on PRL secretion. These findings suggest that CRH-R(1) mediates, at least in part, the restraint stress effects on the HPA, PRL, and reproductive axes.

  14. Assessment of cellular estrogenic activity based on estrogen receptor-mediated reduction of soluble-form catechol-O-methyltransferase (COMT expression in an ELISA-based system.

    Directory of Open Access Journals (Sweden)

    Philip Wing-Lok Ho

    Full Text Available Xenoestrogens are either natural or synthetic compounds that mimic the effects of endogenous estrogen. These compounds, such as bisphenol-A (BPA, and phthalates, are commonly found in plastic wares. Exposure to these compounds poses major risk to human health because of the potential to cause endocrine disruption. There is huge demand for a wide range of chemicals to be assessed for such potential for the sake of public health. Classical in vivo assays for endocrine disruption are comprehensive but time-consuming and require sacrifice of experimental animals. Simple preliminary in vitro screening assays can reduce the time and expense involved. We previously demonstrated that catechol-O-methyltransferase (COMT is transcriptionally regulated by estrogen via estrogen receptor (ER. Therefore, detecting corresponding changes of COMT expression in estrogen-responsive cells may be a useful method to estimate estrogenic effects of various compounds. We developed a novel cell-based ELISA to evaluate cellular response to estrogenicity by reduction of soluble-COMT expression in ER-positive MCF-7 cells exposed to estrogenic compounds. In contrast to various existing methods that only detect bioactivity, this method elucidates direct physiological effect in a living cell in response to a compound. We validated our assay using three well-characterized estrogenic plasticizers - BPA, benzyl butyl phthalate (BBP, and di-n-butyl phthalate (DBP. Cells were exposed to either these plasticizers or 17β-estradiol (E2 in estrogen-depleted medium with or without an ER-antagonist, ICI 182,780, and COMT expression assayed. Exposure to each of these plasticizers (10(-9-10(-7M dose-dependently reduced COMT expression (p<0.05, which was blocked by ICI 182,780. Reduction of COMT expression was readily detectable in cells exposed to picomolar level of E2, comparable to other in vitro assays of similar sensitivity. To satisfy the demand for in vitro assays targeting different

  15. The P2Y2 receptor mediates uptake of matrix-retained and aggregated low density lipoprotein in primary vascular smooth muscle cells

    Science.gov (United States)

    Dissmore, Tixieanna; Seye, Cheikh I.; Medeiros, Denis M.; Weisman, Gary A.; Bardford, Barry; Mamedova, Laman

    2016-01-01

    Background and aims The internalization of aggregated low-density lipoproteins (agLDL) mediated by low-density lipoprotein receptor related protein (LRP1) may involve the actin cytoskeleton in ways that differ from the endocytosis of soluble LDL by the LDL receptor (LDLR). This study aims to define novel mechanisms of agLDL uptake through modulation of the actin cytoskeleton, to identify molecular targets involved in foam cell formation in vascular smooth muscle cells (VSMCs). The critical observation that formed the basis for these studies is that under pathophysiological conditions, nucleotide release from blood-derived and vascular cells activates SMC P2Y2 receptors (P2Y2Rs) leading to rearrangement of the actin cytoskeleton and cell motility. Therefore, we tested the hypothesis that P2Y2R activation mediates agLDL uptake by VSMCs. Methods Primary VSMCs were isolated from aortas of wild type (WT) C57BL/6 and.P2Y2R−/− mice to investigate whether P2Y2R activation modulates LRP1 expression. Cells were transiently transfected with cDNA encoding a hemagglutinin-tagged (HA-tagged) WT P2Y2R, or a mutant P2Y2R that unlike the WT P2Y2R does not bind the cytoskeletal actin-binding protein filamin-A (FLN-A). Results P2Y2R activation significantly increased agLDL uptake, and LRP1 mRNA expression decreased in P2Y2R−/− VSMCs versus WT. SMCs, expressing P2Y2R defective in FLN-A binding, exhibit 3-fold lower LDLR expression levels than SMCs expressing WT P2Y2R, while cells transfected with WT P2Y2R show greater agLDL uptake in both WT and P2Y2R−/− VSMCs versus cells transfected with the mutant P2Y2R. Conclusions Together, these results show that both LRP1 and LDLR expression and agLDL uptake are regulated by P2Y2R in VSMCs, and that agLDL uptake due to P2Y2R activation is dependent upon cytoskeletal reorganization mediated by P2Y2R binding to FLN-A. PMID:27522265

  16. Ligustrazine attenuates oxidative stress-induced activation of hepatic stellate cells by interrupting platelet-derived growth factor-β receptor-mediated ERK and p38 pathways

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Feng [Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029 (China); Ni, Chunyan [Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029 (China); The First People' s Hospital of Changzhou, Changzhou 213003 (China); Kong, Desong; Zhang, Xiaoping; Zhu, Xiaojing; Chen, Li [Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029 (China); Lu, Yin [Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029 (China); Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210046 (China); National First-Class Key Discipline for Traditional Chinese Medicine of Nanjing University of Chinese Medicine, Nanjing 210046 (China); Zheng, Shizhong, E-mail: nytws@163.com [Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210029 (China); Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210046 (China); National First-Class Key Discipline for Traditional Chinese Medicine of Nanjing University of Chinese Medicine, Nanjing 210046 (China)

    2012-11-15

    Hepatic fibrosis represents a frequent event following chronic insult to trigger wound healing reactions with accumulation of extracellular matrix (ECM) in the liver. Activation of hepatic stellate cells (HSCs) is the pivotal event during liver fibrogenesis. Compelling evidence indicates that oxidative stress is concomitant with liver fibrosis irrespective of the underlying etiology. Natural antioxidant ligustrazine exhibits potent antifibrotic activities, but the mechanisms are poorly understood. Our studies were to investigate the ligustrazine effects on HSC activation stimulated by hydrogen peroxide (H{sub 2}O{sub 2}), an in vitro model mimicking the oxidative stress in liver fibrogenesis, and to elucidate the possible mechanisms. Our results demonstrated that H{sub 2}O{sub 2} at 5 μM significantly stimulated HSC proliferation and expression of marker genes of HSC activation; whereas ligustrazine dose-dependently suppressed proliferation and induced apoptosis in H{sub 2}O{sub 2}-activated HSCs, and attenuated expression of fibrotic marker genes. Mechanistic investigations revealed that ligustrazine reduced platelet-derived growth factor-β receptor (PDGF-βR) expression and blocked the phosphorylation of extracellular regulated protein kinase (ERK) and p38 kinase, two downstream effectors of PDGF-βR. Further molecular evidence suggested that ligustrazine interruption of ERK and p38 pathways was dependent on the blockade of PDGF-βR and might be involved in ligustrazine reduction of fibrotic marker gene expression under H{sub 2}O{sub 2} stimulation. Furthermore, ligustrazine modulated some proteins critical for HSC activation and ECM homeostasis in H{sub 2}O{sub 2}-stimulated HSCs. These data collectively indicated that ligustrazine could attenuate HSC activation caused by oxidative stress, providing novel insights into ligustrazine as a therapeutic option for hepatic fibrosis. Highlights: ► Ligustrazine inhibits oxidative stress-induced HSC activation.

  17. Molecular mechanisms of calcium-sensing receptor-mediated calcium signaling in the modulation of epithelial ion transport and bicarbonate secretion.

    Science.gov (United States)

    Xie, Rui; Dong, Xiao; Wong, Chase; Vallon, Volker; Tang, Bo; Sun, Jun; Yang, Shiming; Dong, Hui

    2014-12-12

    Epithelial ion transport is mainly under the control of intracellular cAMP and Ca(2+) signaling. Although the molecular mechanisms of cAMP-induced epithelial ion secretion are well defined, those induced by Ca(2+) signaling remain poorly understood. Because calcium-sensing receptor (CaSR) activation results in an increase in cytosolic Ca(2+) ([Ca(2+)]cyt) but a decrease in cAMP levels, it is a suitable receptor for elucidating the mechanisms of [Ca(2+)]cyt-mediated epithelial ion transport and duodenal bicarbonate secretion (DBS). CaSR proteins have been detected in mouse duodenal mucosae and human intestinal epithelial cells. Spermine and Gd(3+), two CaSR activators, markedly stimulated DBS without altering duodenal short circuit currents in wild-type mice but did not affect DBS and duodenal short circuit currents in cystic fibrosis transmembrane conductance regulator (CFTR) knockout mice. Clotrimazole, a selective blocker of intermediate conductance Ca(2+)-activated K(+) channels but not chromanol 293B, a selective blocker of cAMP-activated K(+) channels (KCNQ1), significantly inhibited CaSR activator-induced DBS, which was similar in wild-type and KCNQ1 knockout mice. HCO3 (-) fluxes across epithelial cells were activated by a CFTR activator, but blocked by a CFTR inhibitor. CaSR activators induced HCO3 (-) fluxes, which were inhibited by a receptor-operated channel (ROC) blocker. Moreover, CaSR activators dose-dependently raised cellular [Ca(2+)]cyt, which was abolished in Ca(2+)-free solutions and inhibited markedly by selective CaSR antagonist calhex 231, and ROC blocker in both animal and human intestinal epithelial cells. Taken together, CaSR activation triggers Ca(2+)-dependent DBS, likely through the ROC, intermediate conductance Ca(2+)-activated K(+) channels, and CFTR channels. This study not only reveals that [Ca(2+)]cyt signaling is critical to modulate DBS but also provides novel insights into the molecular mechanisms of CaSR-mediated Ca(2+)-induced

  18. Alpha5 nicotinic acetylcholine receptor mediates nicotine-induced HIF-1α and VEGF expression in non-small cell lung cancer

    International Nuclear Information System (INIS)

    : • α5-nAChR and HIF-1α over-expressed in NSCLC and correlated with each other. • Nicotine induces cell proliferation and over-expressions of α5-nAChR, HIF-1α and VEGF in NSCLC. • Silence of α5-nAChR inhibited nicotine-induced A549 cell proliferation. • α5-nAChR involved in nicotine-induced HIF-1α and VEGF expression. • Down-regulation of α5-nAChR decreased the phosphorylation level of ERK1/2 and Akt

  19. Genomic variation in the MMP-1 promoter influences estrogen receptor mediated activity in a mechanically activated environment: potential implications for microgravity risk assessment

    Science.gov (United States)

    Thaler, John; Myers, Ken; Lu, Ting; Hart, David

    Background: Mechanotransduction, the conversion of mechanical forces (tensile, compression, shear etc.) into cellular signals is a significant response mechanism in bone that contributes to the balance between formation and resorption and helps maintain bone density. In microgravity the lack of mechanical signals can lead to a loss of bone density, however the signaling pathways responsible are not well understood. For women, sex-specific hormones are also important in maintaining bone density since estrogen deficiency is a major factor in the etiology of osteoporosis in postmenopausal women. Estrogen Receptors (ERs) are present in human connective tissue cells such as osteoblasts and may play a role in mechanotransduction responses. The two ER isoforms, alpha (ER-α) and beta (ER-β) differentially regulate expression of matrixmetalloproteinases (MMPs) which degrade extracellular matrix components found in connective tissues. Mechanical stimulation is known to affect the expression of MMP-1, a collagenase involved in the bone resorption process. The MMP-1 promoter region contains a single nucleotide polymorphism of an additional guanine (G) at position -1607 bp which creates a binding site for a member of the Ets family of mammalian transcription factors. The 2G allele is known to be present in 45-70% of healthy populations and has been associated with higher MMP-1 expression. The 2G allele has been linked to higher risk of several types of cancer but a link to osteoporosis or microgravity induced bone loss has not been explored. The purpose of the present study was to conduct a case-study to determine whether small genetic variations can influence cellular and tissue responses to mechanical loading. Specifically we examined the potential of the 1G/2G -1607 MMP-1 promoter SNP to alter the interplay between mechanical shear stress and estrogen receptors in controlling MMP-1 expression. Methods: Rabbit synovial cells (HIG-82) were used as an in vitro model system to

  20. Alpha5 nicotinic acetylcholine receptor mediates nicotine-induced HIF-1α and VEGF expression in non-small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Xiaoli; Jia, Yanfei; Zu, Shanshan [Central Laboratory, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013 (China); Li, Ruisheng [Institute of Infectious Diseases, 302 Military Hospital, Beijing 100039 (China); Jia, Ying; Zhao, Yun; Xiao, Dongjie [Central Laboratory, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013 (China); Dang, Ningning [Department of Dermatology, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013 (China); Wang, Yunshan [Central Laboratory, Jinan Central Hospital Affiliated to Shandong University, Jinan 250013 (China)

    2014-07-15

    : • α5-nAChR and HIF-1α over-expressed in NSCLC and correlated with each other. • Nicotine induces cell proliferation and over-expressions of α5-nAChR, HIF-1α and VEGF in NSCLC. • Silence of α5-nAChR inhibited nicotine-induced A549 cell proliferation. • α5-nAChR involved in nicotine-induced HIF-1α and VEGF expression. • Down-regulation of α5-nAChR decreased the phosphorylation level of ERK1/2 and Akt.

  1. Relationship between SU Subdomains That Regulate the Receptor-Mediated Transition from the Native (Fusion-Inhibited) to the Fusion-Active Conformation of the Murine Leukemia Virus Glycoprotein

    OpenAIRE

    Lavillette, Dimitri; Ruggieri, Alessia; Boson, Bertrand; Maurice, Marielle; Cosset, François-Loïc

    2002-01-01

    Envelope glycoproteins (Env) of retroviruses are trimers of SU (surface) and TM (transmembrane) heterodimers and are expressed on virions in fusion-competent forms that are likely to be metastable. Activation of the viral receptor-binding domain (RBD) via its interaction with a cell surface receptor is thought to initiate a cascade of events that lead to refolding of the Env glycoprotein into its stable fusion-active conformation. While the fusion-active conformation of the TM subunit has bee...

  2. Roles of Chemokines in Thymopoiesis: Redundancy and Regulation

    Institute of Scientific and Technical Information of China (English)

    Wenxian Fu; Weifeng Chen

    2004-01-01

    Thymus is the primary lymphoid organ involved in the development of thymocytes. Maturation related events of thymocytes within thymus, especially the widely discussed directional migration of thymocytes, is regulated by chemokines via chemokine receptors mediated signaling pathway. Multiple types of chemokines and chemokine receptors, as components of the network-interaction within thymic microenvironment, are involved in the thymopoiesis. It appears that these chemokines are functionally redundant and such phenomenon may be explained not only by the promiscuous, non-one-to-one matching between ligands-receptors within CXC or CC chemokine subfamily, but also by the various spatio-temporal expression patterns within different cell types and developmental stages. The redundancy and regulation of thymus expressed chemokines and chemokine receptors during thymocyte development are herein discussed.

  3. Roles of Chemokines in Thymopoiesis: Redundancy and Regulation

    Institute of Scientific and Technical Information of China (English)

    WenxianFu; WeifengChen

    2004-01-01

    Thymus is the primary lymphoid organ involved in the development of thymocytes. Maturation related events of thymocytes within thymus, especially the widely discussed directional migration of thymocytes, is regulated by chemokines via chemokine receptors mediated signaling pathway. Multiple types of chemokines and chemokine receptors, as components of the network-interaction within thymic microenvironment, are involved in the thymopoiesis. It appears that these chemokines are functionally redundant and such phenomenon may be explained not only by the promiscuous, non-one-to-one matching between ligands-receptors within CXC or CC chemokine subfamily, but also by the various spatio-temporal expression patterns within different cell types and developmental stages. The redundancy and regulation of thymus expressed chemokines and chemokine receptors during thymocyte development are herein discussed. Cellular & Molecular Immunology.

  4. Novel agonists for serotonin 5-HT7 receptors reverse metabotropic glutamate receptor-mediated long-term depression in the hippocampus of wild-type and Fmr1 KO mice, a model of Fragile X Syndrome

    Directory of Open Access Journals (Sweden)

    Lara eCosta

    2015-03-01

    Full Text Available Serotonin 5-HT7 receptors are expressed in the hippocampus and modulate the excitability of hippocampal neurons. We have previously shown that 5-HT7 receptors modulate glutamate-mediated hippocampal synaptic transmission and long-term synaptic plasticity. In particular, we have shown that activation of 5-HT7 receptors reversed metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD in wild-type (wt and in Fmr1 KO mice, a mouse model of Fragile X syndrome in which mGluR-LTD is abnormally enhanced, suggesting that 5-HT7 receptor agonists might be envisaged as a novel therapeutic strategy for Fragile X syndrome. In this perspective, we have characterized the basic in vitro pharmacokinetic properties of novel molecules with high binding affinity and selectivity for 5-HT7 receptors and we have tested their effects on synaptic plasticity using patch clamp on acute hippocampal slices.Here we show that LP-211, a high affinity selective agonist of 5-HT7 receptors, reverses mGluR-LTD in wt and Fmr1 KO mice, correcting a synaptic malfunction in the mouse model of Fragile X syndrome. Among novel putative agonists of 5-HT7 receptors, the compound BA-10 displayed improved affinity and selectivity for 5-HT7 receptors and improved in vitro pharmacokinetic properties with respect to LP-211. BA-10 significantly reversed mGluR-LTD in the CA3-CA1 synapse in wt and Fmr1KO mice, indicating that BA-10 behaved as a highly effective agonist of 5-HT7 receptors and reduced exaggerated mGluR-LTD in a mouse model of Fragile X Syndrome. On the other side, the compounds RA-7 and PM-20, respectively arising from in vivo metabolism of LP-211 and BA-10, had no effect on mGluR-LTD thus did not behave as agonists of 5-HT7 receptors in our conditions.The present results provide information about the structure-activity relationship of novel 5-HT7 receptor agonists and indicate that LP-211 and BA-10 might be used as novel pharmacological tools for the therapy of

  5. Novel agonists for serotonin 5-HT7 receptors reverse metabotropic glutamate receptor-mediated long-term depression in the hippocampus of wild-type and Fmr1 KO mice, a model of Fragile X Syndrome.

    Science.gov (United States)

    Costa, Lara; Sardone, Lara M; Lacivita, Enza; Leopoldo, Marcello; Ciranna, Lucia

    2015-01-01

    Serotonin 5-HT7 receptors are expressed in the hippocampus and modulate the excitability of hippocampal neurons. We have previously shown that 5-HT7 receptors modulate glutamate-mediated hippocampal synaptic transmission and long-term synaptic plasticity. In particular, we have shown that activation of 5-HT7 receptors reversed metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD) in wild-type (wt) and in Fmr1 KO mice, a mouse model of Fragile X Syndrome in which mGluR-LTD is abnormally enhanced, suggesting that 5-HT7 receptor agonists might be envisaged as a novel therapeutic strategy for Fragile X Syndrome. In this perspective, we have characterized the basic in vitro pharmacokinetic properties of novel molecules with high binding affinity and selectivity for 5-HT7 receptors and we have tested their effects on synaptic plasticity using patch clamp on acute hippocampal slices. Here we show that LP-211, a high affinity selective agonist of 5-HT7 receptors, reverses mGluR-LTD in wt and Fmr1 KO mice, correcting a synaptic malfunction in the mouse model of Fragile X Syndrome. Among novel putative agonists of 5-HT7 receptors, the compound BA-10 displayed improved affinity and selectivity for 5-HT7 receptors and improved in vitro pharmacokinetic properties with respect to LP-211. BA-10 significantly reversed mGluR-LTD in the CA3-CA1 synapse in wt and Fmr1KO mice, indicating that BA-10 behaved as a highly effective agonist of 5-HT7 receptors and reduced exaggerated mGluR-LTD in a mouse model of Fragile X Syndrome. On the other side, the compounds RA-7 and PM-20, respectively arising from in vivo metabolism of LP-211 and BA-10, had no effect on mGluR-LTD thus did not behave as agonists of 5-HT7 receptors in our conditions. The present results provide information about the structure-activity relationship of novel 5-HT7 receptor agonists and indicate that LP-211 and BA-10 might be used as novel pharmacological tools for the therapy of Fragile X Syndrome

  6. Ga-66 labeled somatostatin analogue DOTA-DPhe1-Tyr3-octreotide as a potential agent for positron emission tomography imaging and receptor mediated internal radiotherapy of somatostatin receptor positive tumors

    International Nuclear Information System (INIS)

    Radionuclide labeled somatostatin analogues selectively target somatostatin receptor (SSTR)-expressing tumors as a basis for diagnosis and treatment of these tumors. Recently, a DOTA-functionalized somatostatin analogue, DOTATOC (DOTA-DPhe1-Tyr3-octreotide) has been developed. This compound has been shown to be superior to the other somatostatin analogues as indicated by its uniquely high tumor-to-non-target tissue ratio. DOTATOC can be labeled with a variety of radiometals including gallium radioisotopes. Gallium-66 is a positron emitting radionuclide (T1/2 =9.5 hr; β+=56%), that can be produced in carrier free form by a low-beam energy cyclotron. In this study we investigated SSTR targeting characteristics of 66Ga-DOTATOC in AR42J rat pancreas tumor implanted nude mice as a potential agent for diagnosis and receptor-mediated internal radiotherapy of SSTR-expressing tumors. We compared our results with 67Ga- and 68Ga- labeled DOTATOC. The radiolabeling procedure gave labeling yield ranged from 85-95% and radiochemical and chemical purity was >95%. In-vitro competitive binding curves and in-vivo competitive displacement studies with an excess of unlabeled peptide indicates that there is specific binding of the radioligand to SSTR. Animal biodistribution data and serial microPETTM images demonstrated rapid tumor uptake and rapid clearance from the blood and all tissues except kidney. Maximum % ID/g values for tumor were 10.0±0.7, 13.2±2.1 and 9.8±1.5 for 66Ga-, 67Ga-, and 68Ga-DOTATOC, respectively. Calculated tumor, kidney and bone marrow doses for 66Ga-DOTATOC based on biodistribution data were 178, 109 and 1.2 cGy/MBq, respectively. We conclude that 66Ga labeled DOTATOC can be used for PET diagnosis and quantitative imaging-based dosimetry of SSTR positive tumors. 66Ga-DOTATOC may also be used in higher doses for ablation of these tumors. However, kidney is the critical organ for toxicity (tumor/kidney ratio 1.64), and high kidney uptake must be eliminated

  7. V1a vasopressin receptors maintain normal blood pressure by regulating circulating blood volume and baroreflex sensitivity

    OpenAIRE

    Koshimizu, Taka-aki; Nasa, Yoshihisa; Tanoue, Akito; Oikawa, Ryo; Kawahara, Yuji; Kiyono, Yasushi; ADACHI, TETSUYA; Tanaka, Toshiki; Kuwaki, Tomoyuki; Mori, Toyoki; Takeo, Satoshi; Okamura, Hitoshi; Tsujimoto, Gozoh

    2006-01-01

    Arginine-vasopressin (AVP) is a hormone that is essential for both osmotic and cardiovascular homeostasis, and exerts important physiological regulation through three distinct receptors, V1a, V1b, and V2. Although AVP is used clinically as a potent vasoconstrictor (V1a receptor-mediated) in patients with circulatory shock, the physiological role of vasopressin V1a receptors in blood pressure (BP) homeostasis is ill-defined. In this study, we investigated the functional roles of the V1a recept...

  8. Auxin regulation of cell polarity in plants.

    Science.gov (United States)

    Pan, Xue; Chen, Jisheng; Yang, Zhenbiao

    2015-12-01

    Auxin is well known to control pattern formation and directional growth at the organ/tissue levels via the nuclear TIR1/AFB receptor-mediated transcriptional responses. Recent studies have expanded the arena of auxin actions as a trigger or key regulator of cell polarization and morphogenesis. These actions require non-transcriptional responses such as changes in the cytoskeleton and vesicular trafficking, which are commonly regulated by ROP/Rac GTPase-dependent pathways. These findings beg for the question about the nature of auxin receptors that regulate these responses and renew the interest in ABP1 as a cell surface auxin receptor, including the work showing auxin-binding protein 1 (ABP1) interacts with the extracellular domain of the transmembrane kinase (TMK) receptor-like kinases in an auxin-dependent manner, as well as the debate on this auxin binding protein discovered about 40 years ago. This review highlights recent work on the non-transcriptional auxin signaling mechanisms underscoring cell polarity and shape formation in plants. PMID:26599954

  9. Transcriptional Regulation by Nuclear Corepressors and PGC-1α: Implications for Mitochondrial Quality Control and Insulin Sensitivity

    Directory of Open Access Journals (Sweden)

    Zhengtang Qi

    2012-01-01

    Full Text Available The peroxisome proliferator-activated receptors (PPARs and estrogen-related receptor (ERRα are ligand-activated nuclear receptors that coordinately regulate gene expression. Recent evidence suggests that nuclear corepressors, NCoR, RIP140, and SMRT, repress nuclear receptors-mediated transcriptional activity on specific promoters, and thus regulate insulin sensitivity, adipogenesis, mitochondrial number, and activity in vivo. Moreover, the coactivator PGC-1α that increases mitochondrial biogenesis during exercise and calorie restriction directly regulates autophagy in skeletal muscle and mitophagy in the pathogenesis of Parkinson's disease. In this paper, we discuss the PGC-1α’s novel role in mitochondrial quality control and the role of nuclear corepressors in regulating insulin sensitivity and interacting with PGC-1α.

  10. Importins and Exportins Regulating Allergic Immune Responses

    Directory of Open Access Journals (Sweden)

    Ankita Aggarwal

    2014-01-01

    Full Text Available Nucleocytoplasmic shuttling of macromolecules is a well-controlled process involving importins and exportins. These karyopherins recognize and bind to receptor-mediated intracellular signals through specific signal sequences that are present on cargo proteins and transport into and out of the nucleus through nuclear pore complexes. Nuclear localization signals (NLS present on cargo molecules to be imported while nuclear export signals (NES on the molecules to be exported are recognized by importins and exportins, respectively. The classical NLS are found on many transcription factors and molecules that are involved in the pathogenesis of allergic diseases. In addition, several immune modulators, including corticosteroids and vitamin D, elicit their cellular responses by regulating the expression and activity of importin molecules. In this review article, we provide a comprehensive list of importin and exportin molecules and their specific cargo that shuttled between cytoplasm and the nucleus. We also critically review the role and regulation of specific importin and exportin involved in the transport of activated transcription factors in allergic diseases, the underlying molecular mechanisms, and the potential target sites for developing better therapeutic approaches.

  11. Diacylglycerol Kinases: Regulated Controllers of T Cell Activation, Function, and Development

    Directory of Open Access Journals (Sweden)

    Gary A. Koretzky

    2013-03-01

    Full Text Available Diacylglycerol kinases (DGKs are a diverse family of enzymes that catalyze the conversion of diacylglycerol (DAG, a crucial second messenger of receptor-mediated signaling, to phosphatidic acid (PA. Both DAG and PA are bioactive molecules that regulate a wide set of intracellular signaling proteins involved in innate and adaptive immunity. Clear evidence points to a critical role for DGKs in modulating T cell activation, function, and development. More recently, studies have elucidated factors that control DGK function, suggesting an added complexity to how DGKs act during signaling. This review summarizes the available knowledge of the function and regulation of DGK isoforms in signal transduction with a particular focus on T lymphocytes.

  12. Central cholinergic regulation of respiration: nicotinic receptors

    Institute of Scientific and Technical Information of China (English)

    Xuesi M SHAO; Jack L FELDMAN

    2009-01-01

    Nicotinic acetylcholine receptors (nAChRs) are expressed in brainstem and spinal cord regions involved in the control of breathing. These receptors mediate central cholinergic regulation of respiration and effects of the exogenous ligand nicotine on respiratory pattern. Activation of a4* nAChRs in the preBotzinger Complex (preBotC), an essential site for normal respiratory rhythm generation in mammals, modulates excitatory glutamatergic neurotransmission and depolarizes preBotC inspiratory neurons, leading to increases in respiratory frequency. nAChRs are also present in motor nuclei innervating respiratory muscles. Activation of post- and/or extra-synaptic a4* nAChRs on hypoglossal (XII) motoneurons depolarizes these neurons, potentiating tonic and respiratory-related rhythmic activity. As perinatal nicotine exposure may contribute to the pathogenesis of sudden infant death syndrome (SIDS), we discuss the effects of perinatal nicotine exposure on development of the cholinergic and other neurotransmitter systems involved in control of breathing. Advances in understanding of the mechanisms underlying central cholinergic/nicotinic modulation of respiration provide a pharmacological basis for exploiting nAChRs as therapeutic targets for neurological disorders related to neural control of breathing such as sleep apnea and SIDS.

  13. Regulation of adenosine levels during cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Stephanie CHU; Wei XIONG; Dali ZHANG; Hanifi SOYLU; Chao SUN; Benedict C ALBENSI; Fiona E PARKINSON

    2013-01-01

    Adenosine is a neuromodulator with its level increasing up to 100-fold during ischemic events,and attenuates the excitotoxic neuronal injury.Adenosine is produced both intracellularly and extracellularly,and nucleoside transport proteins transfer adenosine across plasma membranes.Adenosine levels and receptor-mediated effects of adenosine are regulated by intracellular ATP consumption,cellular release of ATP,metabolism of extracellular ATP (and other adenine nucleotides),adenosine influx,adenosine efflux and adenosine metabolism.Recent studies have used genetically modified mice to investigate the relative contributions of intra-and extracellular pathways for adenosine formation.The importance of cortical or hippocampal neurons as a source or a sink of adenosine under basal and hypoxic/ischemic conditions was addressed through the use of transgenic mice expressing human equilibrative nucleoside transporter 1 (hENT1) under the control of a promoter for neuron-specific enolase.From these studies,we conclude that ATP consumption within neurons is the primary source of adenosine in neuronal cultures,but not in hippocampal slices or in vivo mice exposed to ischemic conditions.

  14. microRNA-146a inhibits G protein-coupled receptor-mediated activation of NF-κB by targeting CARD10 and COPS8 in gastric cancer

    DEFF Research Database (Denmark)

    Crone, Stephanie Geisler; Jacobsen, Anders; Federspiel, Birgitte;

    2012-01-01

    Gastric cancer is the second most common cause of cancer-related death in the world. Inflammatory signals originating from gastric cancer cells are important for recruiting inflammatory cells and regulation of metastasis of gastric cancer. Several microRNAs (miRNA) have been shown to be involved ...

  15. microRNA-146a inhibits G protein-coupled receptor-mediated activation of NF-κB by targeting CARD10 and COPS8 in gastric cancer

    Directory of Open Access Journals (Sweden)

    Crone Stephanie

    2012-09-01

    Full Text Available Abstract Background Gastric cancer is the second most common cause of cancer-related death in the world. Inflammatory signals originating from gastric cancer cells are important for recruiting inflammatory cells and regulation of metastasis of gastric cancer. Several microRNAs (miRNA have been shown to be involved in development and progression of gastric cancer. miRNA-146a (miR-146a is a modulator of inflammatory signals, but little is known about its importance in gastric cancer. We therefore wanted to identify targets of miR-146a in gastric cancer and examine its biological roles. Results The expression of miR-146a was evaluated by quantitative PCR (qPCR and found up-regulated in the gastrin knockout mice, a mouse model of gastric cancer, and in 73% of investigated human gastric adenocarcinomas. Expression of miR-146a by gastric cancer cells was confirmed by in situ hybridization. Global analysis of changes in mRNA levels after miR-146a transfection identified two transcripts, caspase recruitment domain-containing protein 10 (CARD10 and COP9 signalosome complex subunit 8 (COPS8, as new miR-146a targets. qPCR, Western blotting and luciferase assays confirmed these transcripts as direct miR-146a targets. CARD10 and COPS8 were shown to be part of the G protein-coupled receptor (GPCR pathway of nuclear factor-kappaB (NF-kappaB activation. Lysophosphatidic acid (LPA induces NF-kappaB activation via this pathway and over-expression of miR-146a inhibited LPA-induced NF-kappaB activation, reduced LPA-induced expression of tumor-promoting cytokines and growth factors and inhibited monocyte attraction. Conclusions miR-146a expression is up-regulated in a majority of gastric cancers where it targets CARD10 and COPS8, inhibiting GPCR-mediated activation of NF-kappaB, thus reducing expression of NF-kappaB-regulated tumor-promoting cytokines and growth factors. By targeting components of several NF-kappaB-activating pathways, miR-146a is a key component in

  16. SUMO: regulating the regulator

    Directory of Open Access Journals (Sweden)

    Bossis Guillaume

    2006-06-01

    Full Text Available Abstract Post-translational modifiers of the SUMO (Small Ubiquitin-related Modifier family have emerged as key regulators of protein function and fate. While the past few years have seen an enormous increase in knowledge on SUMO enzymes, substrates, and consequences of modification, regulation of SUMO conjugation is far from being understood. This brief review will provide an overview on recent advances concerning (i the interplay between sumoylation and other post-translational modifications at the level of individual targets and (ii global regulation of SUMO conjugation and deconjugation.

  17. Modeling analysis of inositol 1,4,5-trisphosphate receptor-mediated Ca2+ mobilization under the control of glucagon-like peptide-1 in mouse pancreatic β-cells.

    Science.gov (United States)

    Takeda, Yukari; Shimayoshi, Takao; Holz, George G; Noma, Akinori

    2016-03-01

    Glucagon-like peptide-1 (GLP-1) is an intestinally derived blood glucose-lowering hormone that potentiates glucose-stimulated insulin secretion from pancreatic β-cells. The secretagogue action of GLP-1 is explained, at least in part, by its ability to stimulate cAMP production so that cAMP may facilitate the release of Ca(2+) from inositol trisphosphate receptor (IP3R)-regulated Ca(2+) stores. However, a quantitative model has yet to be provided that explains the molecular mechanisms and dynamic processes linking GLP-1-stimulated cAMP production to Ca(2+) mobilization. Here, we performed simulation studies to investigate how GLP-1 alters the abilities of Ca(2+) and IP3 to act as coagonists at IP3R Ca(2+) release channels. A new dynamic model was constructed based on the Kaftan model, which demonstrates dual steady-state allosteric regulation of the IP3R by Ca(2+) and IP3. Data obtained from β-cells were then analyzed to understand how GLP-1 facilitates IP3R-mediated Ca(2+) mobilization when UV flash photolysis is used to uncage Ca(2+) and IP3 intracellularly. When the dynamic model for IP3R activation was incorporated into a minimal cell model, the Ca(2+) transients and oscillations induced by GLP-1 were successfully reconstructed. Simulation studies indicated that transient and oscillatory responses to GLP-1 were produced by sequential positive and negative feedback regulation due to fast activation and slow inhibition of the IP3R by Ca(2+). The slow rate of Ca(2+)-dependent inhibition was revealed to provide a remarkable contribution to the time course of the decay of cytosolic Ca(2+) transients. It also served to drive and pace Ca(2+) oscillations that are significant when evaluating how GLP-1 stimulates insulin secretion. PMID:26741144

  18. BMP-2 Induced Expression of Alx3 That Is a Positive Regulator of Osteoblast Differentiation.

    Directory of Open Access Journals (Sweden)

    Takashi Matsumoto

    Full Text Available Bone morphogenetic proteins (BMPs regulate many aspects of skeletal development, including osteoblast and chondrocyte differentiation, cartilage and bone formation, and cranial and limb development. Among them, BMP-2, one of the most potent osteogenic signaling molecules, stimulates osteoblast differentiation, while it inhibits myogenic differentiation in C2C12 cells. To evaluate genes involved in BMP-2-induced osteoblast differentiation, we performed cDNA microarray analyses to compare BMP-2-treated and -untreated C2C12 cells. We focused on Alx3 (aristaless-like homeobox 3 which was clearly induced during osteoblast differentiation. Alx3, a homeobox gene related to the Drosophilaaristaless gene, has been linked to developmental functions in craniofacial structures and limb development. However, little is known about its direct relationship with bone formation. In the present study, we focused on the mechanisms of Alx3 gene expression and function during osteoblast differentiation induced by BMP-2. In C2C12 cells, BMP-2 induced increase of Alx3 gene expression in both time- and dose-dependent manners through the BMP receptors-mediated SMAD signaling pathway. In addition, silencing of Alx3 by siRNA inhibited osteoblast differentiation induced by BMP-2, as showed by the expressions of alkaline phosphatase (Alp, Osteocalcin, and Osterix, while over-expression of Alx3 enhanced osteoblast differentiation induced by BMP-2. These results indicate that Alx3 expression is enhanced by BMP-2 via the BMP receptors mediated-Smad signaling and that Alx3 is a positive regulator of osteoblast differentiation induced by BMP-2.

  19. Nfkb1 activation by the E26 transformation-specific transcription factors PU.1 and Spi-B promotes Toll-like receptor-mediated splenic B cell proliferation.

    Science.gov (United States)

    Li, Stephen K H; Abbas, Ali K; Solomon, Lauren A; Groux, Gaëlle M N; DeKoter, Rodney P

    2015-05-01

    Generation of antibodies against T-independent and T-dependent antigens requires Toll-like receptor (TLR) engagement on B cells for efficient responses. However, the regulation of TLR expression and responses in B cells is not well understood. PU.1 and Spi-B (encoded by Sfpi1 and Spib, respectively) are transcription factors of the E26 transformation-specific (ETS) family and are important for B cell development and function. It was found that B cells from mice knocked out for Spi-B and heterozygous for PU.1 (Sfpi1(+/-) Spib(-/-) [PUB] mice) proliferated poorly in response to TLR ligands compared to wild-type (WT) B cells. The NF-κB family member p50 (encoded by Nfkb1) is required for lipopolysaccharide (LPS) responsiveness in mice. PUB B cells expressed reduced Nfkb1 mRNA transcripts and p50 protein. The Nfkb1 promoter was regulated directly by PU.1 and Spi-B, as shown by reporter assays and chromatin immunoprecipitation analysis. Occupancy of the Nfkb1 promoter by PU.1 was reduced in PUB B cells compared to that in WT B cells. Finally, infection of PUB B cells with a retroviral vector encoding p50 substantially restored proliferation in response to LPS. We conclude that Nfkb1 transcriptional activation by PU.1 and Spi-B promotes TLR-mediated B cell proliferation.

  20. Ghrelin receptor activity amplifies hippocampal N-methyl-d-aspartate receptor-mediated postsynaptic currents and increases phosphorylation of the GluN1 subunit at Ser896 and Ser897.

    Science.gov (United States)

    Muniz, Brandon G; Isokawa, Masako

    2015-12-01

    Although ghrelin and its cognate receptor growth hormone secretagogue receptor (GHSR1a) are highly localized in the hypothalamic nuclei for the regulation of metabolic states and feeding, GHSR1a is also highly localized in the hippocampus, suggesting its involvement in extra-hypothalamic functions. Indeed, exogenous application of ghrelin has been reported to improve hippocampal learning and memory. However, the underlying mechanism of ghrelin regulation of hippocampal functions is poorly understood. Here, we report ghrelin-promoted phosphorylation of GluN1 and amplified N-methyl-d-aspartate receptor (NMDAR)-mediated excitatory postsynaptic currents in the CA1 pyramidal cells of the hippocampus in slice preparations. The ghrelin-induced responses were sensitive to a GHSR1a antagonist and inverse agonist, and were absent in GHSR1a homozygous knock-out mice. These results indicated that activation of GHSR1a was critical in the ghrelin-induced enhancement of the NMDAR function. Interestingly, heterozygous mouse hippocampi were also insensitive to ghrelin treatment, suggesting that a slight reduction in the availability of GHSR1a may be sufficient to negate the effect of ghrelin on GluN1 phosphorylation and NMDAR channel activities. In addition, NMDAR-mediated spike currents, which are of dendritic origin, were blocked by the GHSR1a antagonist, suggesting the presence of GHSR1a on the pyramidal cell dendrites in physical proximity to NMDAR. Together with our findings on the localization of GHSR1a in the CA1 region of the hippocampus, which was shown by fluorescent ghrelin binding, immunoreactivity, and enhanced green fluorescent protein reporter gene expression, we conclude that the activation of GHSR1a favours rapid modulation of the NMDAR-mediated glutamatergic synaptic transmission by phosphorylating GluN1 in the hippocampus. PMID:26490687

  1. Persistent inflammation-induced up-regulation of brain-derived neurotrophic factor (BDNF) promotes synaptic delivery of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor GluA1 subunits in descending pain modulatory circuits.

    Science.gov (United States)

    Tao, Wenjuan; Chen, Quan; Zhou, Wenjie; Wang, Yunping; Wang, Lu; Zhang, Zhi

    2014-08-01

    The enhanced AMPA receptor phosphorylation at GluA1 serine 831 sites in the central pain-modulating system plays a pivotal role in descending pain facilitation after inflammation, but the underlying mechanisms remain unclear. We show here that, in the rat brain stem, in the nucleus raphe magnus, which is a critical relay in the descending pain-modulating system of the brain, persistent inflammatory pain induced by complete Freund adjuvant (CFA) can enhance AMPA receptor-mediated excitatory postsynaptic currents and the GluA2-lacking AMPA receptor-mediated rectification index. Western blot analysis showed an increase in GluA1 phosphorylation at Ser-831 but not at Ser-845. This was accompanied by an increase in distribution of the synaptic GluA1 subunit. In parallel, the level of histone H3 acetylation at bdnf gene promoter regions was reduced significantly 3 days after CFA injection, as indicated by ChIP assays. This was correlated with an increase in BDNF mRNA levels and BDNF protein levels. Sequestering endogenous extracellular BDNF with TrkB-IgG in the nucleus raphe magnus decreased AMPA receptor-mediated synaptic transmission and GluA1 phosphorylation at Ser-831 3 days after CFA injection. Under the same conditions, blockade of TrkB receptor functions, phospholipase C, or PKC impaired GluA1 phosphorylation at Ser-831 and decreased excitatory postsynaptic currents mediated by GluA2-lacking AMPA receptors. Taken together, these results suggest that epigenetic up-regulation of BDNF by peripheral inflammation induces GluR1 phosphorylation at Ser-831 sites through activation of the phospholipase C-PKC signaling cascade, leading to the trafficking of GluA1 to pain-modulating neuronal synapses.

  2. Caffeine inhibits the activation of hepatic stellate cells induced by acetaldehyde via adenosine A2A receptor mediated by the cAMP/PKA/SRC/ERK1/2/P38 MAPK signal pathway.

    Directory of Open Access Journals (Sweden)

    He Wang

    Full Text Available Hepatic stellate cell (HSC activation is an essential event during alcoholic liver fibrosis. Evidence suggests that adenosine aggravates liver fibrosis via the adenosine A2A receptor (A2AR. Caffeine, which is being widely consumed during daily life, inhibits the action of adenosine. In this study, we attempted to validate the hypothesis that caffeine influences acetaldehyde-induced HSC activation by acting on A2AR. Acetaldehyde at 50, 100, 200, and 400 μM significantly increased HSC-T6 cells proliferation, and cell proliferation reached a maximum at 48 h after exposure to 200 μM acetaldehyde. Caffeine and the A2AR antagonist ZM241385 decreased the cell viability and inhibited the expression of procollagen type I and type III in acetaldehyde-induced HSC-T6 cells. In addition, the inhibitory effect of caffeine on the expression of procollagen type I was regulated by A2AR-mediated signal pathway involving cAMP, PKA, SRC, and ERK1/2. Interestingly, caffeine's inhibitory effect on the expression of procollagen type III may depend upon the A2AR-mediated P38 MAPK-dependent pathway.Caffeine significantly inhibited acetaldehyde-induced HSC-T6 cells activation by distinct A2AR mediated signal pathway via inhibition of cAMP-PKA-SRC-ERK1/2 for procollagen type I and via P38 MAPK for procollagen type III.

  3. Market, Regulation, Market, Regulation

    DEFF Research Database (Denmark)

    Frankel, Christian; Galland, Jean-Pierre

    2015-01-01

    barriers to trade in Europe, realized the free movement of products by organizing progressively several orders of markets and regulation. Based on historical and institutional documents, on technical publications, and on interviews, this article relates how the European Commission and the Member States had......This paper focuses on the European Regulatory system which was settled both for opening the Single Market for products and ensuring the consumers' safety. It claims that the New Approach and Standardization, and the Global Approach to conformity assessment, which suppressed the last technical...... alternatively recourse to markets and to regulations, at the three main levels of the New Approach Directives implementation. The article focuses also more specifically on the Medical Devices sector, not only because this New Approach sector has long been controversial in Europe, and has recently been concerned...

  4. 4-tert-Octylphenol stimulates the expression of cathepsins in human breast cancer cells and xenografted breast tumors of a mouse model via an estrogen receptor-mediated signaling pathway

    International Nuclear Information System (INIS)

    Highlights: ► Cathepsins B and D were markedly enhanced by octylphenol (OP) in MCF-7 cells. ► OP may accelerate breast cancer cell growth and cathepsins via ER-mediated signaling. ► Breast cancer cells exposed with OP to mouse model were more aggressive. ► OP can promote metastasis through the amplification of cathepsins B and D via ER-mediated signaling pathway. -- Abstract: Endocrine disrupting chemicals (EDCs) are defined as environmental compounds that modulate steroid hormone receptor-dependent responses an abnormal manner, resulting in adverse health problems for humans such as cancer growth and metastasis. Cathepsins are proteases that have been implicated in cancer progression. However, there have been few studies about the association between cathepsins and estrogenic chemicals during the cancer progression. In this study, we examined the effect(s) of 4-tert-octylphenol (OP), a potent EDC, on the expression of cathepsins B and D in human MCF-7 breast cancer cells and a xenograft mouse model. Treatment with OP significantly induced the proliferation MCF-7 cells in an MTT assay. In addition, the expression of cathepsins B and D was markedly enhanced in MCF-7 cells at both the transcriptional and the translational levels following treatment with E2 or OP up to 48 h. These results demonstrated the ability of OP to disrupt normal transcriptional regulation of cathepsins B and D in human breast cancer cells. However, the effects of OP on cell growth or overexpression of cathepsins by inhibiting ER-mediated signaling were abolished by an ER antagonist and siRNA specific for ERα. In conclusion, our findings suggest that OP at 10−6 M, like E2, may accelerate breast cancer cell proliferation and the expression of cathepsins through an ER-mediated signaling pathway. In addition, the breast cancer cells exposed with OP to a xenograft mouse model were more aggressive according to our histological analysis and showed markedly increased expression of cathepsin

  5. Pharmacological evidence that 5-HT1A/1B/1D, α2-adrenoceptors and D2-like receptors mediate ergotamine-induced inhibition of the vasopressor sympathetic outflow in pithed rats.

    Science.gov (United States)

    Villamil-Hernández, Ma Trinidad; Alcántara-Vázquez, Oscar; Sánchez-López, Araceli; Gutiérrez-Lara, Erika J; Centurión, David

    2014-10-01

    The sympathetic nervous system that innervates the peripheral circulation is regulated by several mechanisms/receptors. It has been reported that prejunctional 5-HT1A, 5-HT1B, 5-HT1D, D2-like receptors and α2-adrenoceptors mediate the inhibition of the vasopressor sympathetic outflow in pithed rats. In addition, ergotamine, an antimigraine drug, displays affinity at the above receptors and may explain some of its adverse/therapeutic effects. Thus, the aims of this study were to investigate in pithed rats: (i) whether ergotamine produces inhibition of the vasopressor sympathetic outflow; and (ii) the major receptors involved in this effect. For this purpose, male Wistar pithed rats were pre-treated with gallamine (25 mg/kg; i.v.) and desipramine (50 µg/kg) and prepared to stimulate the vasopressor sympathetic outflow (T7-T9; 0.03-3 Hz) or to receive i.v. bolus of exogenous noradrenaline (0.03-3 µg/kg). I.v. continuous infusions of ergotamine (1 and 1.8 μg/kgmin) dose-dependently inhibited the vasopressor responses to sympathetic stimulation but not those to exogenous noradrenaline. The sympatho-inhibition elicited by 1.8 μg/kg min ergotamine was (i) unaffected by saline (1 ml/kg); (ii) partially antagonised by WAY 100635 (5-HT1A; 30 μg/kg) and rauwolscine (α2-adrenoceptor; 300 μg/kg), and (iii) dose-dependently blocked by GR 127935 (5-HT1B/1D; 100 and 300 μg/kg) or raclopride (D2-like; 300 and 1000 μg/kg), The above doses of antagonists did not modify per se the sympathetically-induced vasopressor responses. The above results suggest that ergotamine induces inhibition of the vasopressor sympathetic outflow by activation of prejunctional 5-HT1A, 5-HT1B/1D, α2-adrenoceptors and D2-like receptors in pithed rats. PMID:24975101

  6. The Biochemistry and Regulation of S100A10: A Multifunctional Plasminogen Receptor Involved in Oncogenesis

    Directory of Open Access Journals (Sweden)

    Patricia A. Madureira

    2012-01-01

    Full Text Available The plasminogen receptors mediate the production and localization to the cell surface of the broad spectrum proteinase, plasmin. S100A10 is a key regulator of cellular plasmin production and may account for as much as 50% of cellular plasmin generation. In parallel to plasminogen, the plasminogen-binding site on S100A10 is highly conserved from mammals to fish. S100A10 is constitutively expressed in many cells and is also induced by many diverse factors and physiological stimuli including dexamethasone, epidermal growth factor, transforming growth factor-α, interferon-γ, nerve growth factor, keratinocyte growth factor, retinoic acid, and thrombin. Therefore, S100A10 is utilized by cells to regulate plasmin proteolytic activity in response to a wide diversity of physiological stimuli. The expression of the oncogenes, PML-RARα and KRas, also stimulates the levels of S100A10, suggesting a role for S100A10 in pathophysiological processes such as in the oncogenic-mediated increases in plasmin production. The S100A10-null mouse model system has established the critical role that S100A10 plays as a regulator of fibrinolysis and oncogenesis. S100A10 plays two major roles in oncogenesis, first as a regulator of cancer cell invasion and metastasis and secondly as a regulator of the recruitment of tumor-associated cells, such as macrophages, to the tumor site.

  7. Systemic inflammation regulates microglial responses to tissue damage in vivo

    Science.gov (United States)

    Gyoneva, Stefka; Davalos, Dimitrios; Biswas, Dipankar; Swanger, Sharon A.; Garnier-Amblard, Ethel; Loth, Francis; Akassoglou, Katerina; Traynelis, Stephen F.

    2015-01-01

    Microglia, the resident immune cells of the central nervous system, exist in either a “resting” state associated with physiological tissue surveillance or an “activated” state in neuroinflammation. We recently showed that ATP is the primary chemoattractor to tissue damage in vivo and elicits opposite effects on the motility of activated microglia in vitro through activation of adenosine A2A receptors. However, whether systemic inflammation affects microglial responses to tissue damage in vivo remains largely unknown. Using in vivo two-photon imaging of mice, we show that injection of lipopolysaccharide (LPS) at levels that can produce both clear neuroinflammation and some features of sepsis significantly reduced the rate of microglial response to laser-induced ablation injury in vivo. Under pro-inflammatory conditions, microglial processes initially retracted from the ablation site, but subsequently moved toward and engulfed the damaged area. Analyzing the process dynamics in 3D cultures of primary microglia indicated that only A2A, but not A1 or A3 receptors, mediate process retraction in LPS-activated microglia. The A2A receptor antagonists caffeine and preladenant reduced adenosine-mediated process retraction in activated microglia in vitro. Finally, administration of preladenant before induction of laser ablation in vivo accelerated the microglial response to injury following systemic inflammation. The regulation of rapid microglial responses to sites of injury by A2A receptors could have implications for their ability to respond to the neuronal death occurring under conditions of neuroinflammation in neurodegenerative disorders. PMID:24807189

  8. Differential gene regulation by the SRC family of coactivators

    Institute of Scientific and Technical Information of China (English)

    HuaZhang; XiaYi; Xiaojingsun; NaYin; BinShi; HuijianWu; DanWang; GeWu; YongfengShang

    2005-01-01

    SRCs (steroid receptor coactivatorsl are required for nuclear receptor-mediated transcription and are also implicated in the transcription initiation by other transcription factors, such as STATs and NFKB. Despite phenotypic manifestations in gene knockout mice for SRC-1, GRIP1, and AIB1 of the SRC (Steroid Receptor Coactivator) family indicating their differential roles in animal physiology, there is no clear evidence, at the molecular level, to support a functional specificity for these proteins. We demonstrated in this report that two species of SRC coactivators, either as AIBI:GRIP1 or as AIBI:SRC-1 are recruited, possibly through heterodimerization, on the promoter of genes that contain a classical hormone responsive element (HRE). In contrast, on non-HRE-containing gene promoters, on which steroid receptors bind indirectly, either GRIP1 orSRC-1 is recruited as a monomer, depending on the cellular abundance of the protein. Typically, non-HRE-containing genes are early genes activated by steroid receptors, whereas HRE-containing genes are activated later. Our results also showed that SRC proteins contribute to the temporal regulation of gene transcription. In addition, our experiments revealed a positive correlation between AIB1/c-myc overexpression in ER+ breast carcinoma samples, suggesting a possible mechanism for AIB1/n breast cancer carcinogenesis.

  9. Ionotropic Chemosensory Receptors Mediate the Taste and Smell of Polyamines.

    Directory of Open Access Journals (Sweden)

    Ashiq Hussain

    2016-05-01

    Full Text Available The ability to find and consume nutrient-rich diets for successful reproduction and survival is fundamental to animal life. Among the nutrients important for all animals are polyamines, a class of pungent smelling compounds required in numerous cellular and organismic processes. Polyamine deficiency or excess has detrimental effects on health, cognitive function, reproduction, and lifespan. Here, we show that a diet high in polyamine is beneficial and increases reproductive success of flies, and we unravel the sensory mechanisms that attract Drosophila to polyamine-rich food and egg-laying substrates. Using a combination of behavioral genetics and in vivo calcium imaging, we demonstrate that Drosophila uses multisensory detection to find and evaluate polyamines present in overripe and fermenting fruit, their favored feeding and egg-laying substrate. In the olfactory system, two coexpressed ionotropic receptors (IRs, IR76b and IR41a, mediate the long-range attraction to the odor. In the gustatory system, multimodal taste sensation by IR76b receptor and GR66a bitter receptor neurons is used to evaluate quality and valence of the polyamine providing a mechanism for the fly's high attraction to polyamine-rich and sweet decaying fruit. Given their universal and highly conserved biological roles, we propose that the ability to evaluate food for polyamine content may impact health and reproductive success also of other animals including humans.

  10. Experimental Cannabinoid 2 Receptor-Mediated Immune Modulation in Sepsis

    Directory of Open Access Journals (Sweden)

    J. Sardinha

    2014-01-01

    Full Text Available Sepsis is a complex condition that results from a dysregulated immune system in response to a systemic infection. Current treatments lack effectiveness in reducing the incidence and mortality associated with this disease. The endocannabinoid system offers great promise in managing sepsis pathogenesis due to its unique characteristics. The present study explored the effect of modulating the CB2 receptor pathway in an acute sepsis mouse model. Endotoxemia was induced by intravenous injection of lipopolysaccharide (LPS in mice and intestinal microcirculation was assessed through intravital microscopy. We found that HU308 (CB2 receptor agonist reduced the number of adherent leukocytes in submucosal venules but did not restore muscular and mucosal villi FCD in endotoxemic mice. AM630 (CB2 receptor antagonist maintained the level of adherent leukocytes induced by LPS but further reduced muscular and mucosal villi FCD. URB597 (FAAH inhibitor and JZL184 (MAGL inhibitor both reduced the number of adherent leukocytes in submucosal venules but did not restore the mucosal villi FCD. Using various compounds we have shown different mechanisms of activating CB2 receptors to reduce leukocyte endothelial interactions in order to prevent further inflammatory damage during sepsis.

  11. Receptor-mediated regional sympathetic nerve activation by leptin.

    OpenAIRE

    Haynes, W G; Morgan, D A; Walsh, S A; Mark, A L; Sivitz, W I

    1997-01-01

    Leptin is a peptide hormone produced by adipose tissue which acts centrally to decrease appetite and increase energy expenditure. Although leptin increases norepinephrine turnover in thermogenic tissues, the effects of leptin on directly measured sympathetic nerve activity to thermogenic and other tissues are not known. We examined the effects of intravenous leptin and vehicle on sympathetic nerve activity to brown adipose tissue, kidney, hindlimb, and adrenal gland in anesthetized Sprague-Da...

  12. Nucleus incertus Orexin2 receptors mediate alcohol seeking in rats.

    Science.gov (United States)

    Kastman, Hanna E; Blasiak, Anna; Walker, Leigh; Siwiec, Marcin; Krstew, Elena V; Gundlach, Andrew L; Lawrence, Andrew J

    2016-11-01

    Alcoholism is a chronic relapsing disorder and a major global health problem. Stress is a key precipitant of relapse in human alcoholics and in animal models of alcohol seeking. The brainstem nucleus incertus (NI) contains a population of relaxin-3 neurons that are highly responsive to psychological stressors; and the ascending NI relaxin-3/RXFP3 signalling system is implicated in stress-induced reinstatement of alcohol seeking. The NI receives orexinergic innervation and expresses orexin1 (OX1) and orexin2 (OX2) receptor mRNA. In alcohol-preferring (iP) rats, we examined the impact of yohimbine-induced reinstatement of alcohol seeking on orexin neuronal activation, and the effect of bilateral injections into NI of the OX1 receptor antagonist, SB-334867 (n = 16) or the OX2 receptor antagonist, TCS-OX2-29 (n = 8) on stress-induced reinstatement of alcohol seeking. We also assessed the effects of orexin-A on NI neuronal activity and the involvement of OX1 and OX2 receptors using whole cell patch-clamp recordings in rat brain slices. Yohimbine-induced reinstatement of alcohol seeking activated orexin neurons. Bilateral NI injections of TCS-OX2-29 attenuated yohimbine-induced reinstatement of alcohol seeking. In contrast, intra-NI injection of SB-334867 had no significant effect. In line with these data, orexin-A (600 nM) depolarized a majority of NI neurons recorded in coronal brain slices (18/28 cells), effects prevented by bath application of TCS-OX2-29 (10 μM), but not SB-334867 (10 μM). These data suggest an excitatory orexinergic input to NI contributes to yohimbine-induced reinstatement of alcohol seeking, predominantly via OX2 receptor signalling. PMID:27395787

  13. Regulation and localization of TOB and IFR1 in differentiating red cells.

    Science.gov (United States)

    Steiner, Simone K; Baumann, Rosemarie; Dragon, Stefanie

    2007-08-10

    In differentiating red blood cells (RBCs) of the chick embryo, the synthesis of carbonic anhydrase (CAII) and pyrimidine 5'-nucleotidase (P5N-I) is triggered by the hypoxic mediators norepinephrine and adenosine via receptor-mediated cAMP formation. The process is accompanied by the induction of IFR1 and TOB which are putative regulators of transcription or translation in different cell types. The present investigation studied the erythroid TOB and IFR1 expression: mRNA and protein are up-regulated in post-mitotic RBCs from D11-19 treated with cAMP-elevating agonists. In contrast, immature RBCs of early embryos (D5-7) fail to synthesize a significant amount of IFR1/TOB. In D11 RBCs, TOB and IFR1 are cytosolic proteins with different half-lives (TOB12h). Cytosolic fractionation characterized TOB as a free soluble protein while the abundant IFR1 (c(max) approximately 3microM) is completely associated with the ribosomal fraction. A putative function of both proteins as translational regulators is discussed.

  14. Epigenetic regulation of non-lymphoid cells by Bisphenol-A, a model endocrine disrupter: Potential Implications for Immunoregulation

    Directory of Open Access Journals (Sweden)

    Deena eKhan

    2015-06-01

    Full Text Available Endocrine disrupting chemicals (EDC abound in the environment since many compounds are released from chemical, agricultural, pharmaceutical and consumer product industries. Many of the EDCs such as Bisphenol A (BPA have estrogenic activity or interfere with endogenous sex hormones. Experimental studies have reported a positive correlation of BPA with reproductive toxicity, altered growth and immune dysregulation. Although the precise relevance of these studies to the environmental levels is unclear, nevertheless, their potential health implications remain a concern. One possible mechanism by which BPA can alter genes is by regulating epigenetics, including microRNA, alteration of methylation and histone acetylation. There is now wealth of information on BPA effects on non-lymphoid cells and by comparison, paucity of data on effects of BPA on the immune system. In this mini review, we will highlight BPA regulation of estrogen receptor-mediated immune cell functions and in different inflammatory conditions. In addition, BPA-mediated epigenetic regulation of non-lymphoid cells is emphasized. We recognize that most of these studies are on non-lymphoid cells, and given that BPA also affects the immune system, it is plausible that BPA could have similar epigenetic regulation in immune cells. It is hoped that this review will stimulate studies in this area to ascertain whether or not BPA epigenetically regulates the cells of the immune system.

  15. Salmonella enterica serovar typhi modulates cell surface expression of its receptor, the cystic fibrosis transmembrane conductance regulator, on the intestinal epithelium.

    Science.gov (United States)

    Lyczak, Jeffrey B; Pier, Gerald B

    2002-11-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) protein is an epithelial receptor mediating the translocation of Salmonella enterica serovar Typhi to the gastric submucosa. Since the level of cell surface CFTR is directly related to the efficiency of serovar Typhi translocation, the goal of this study was to measure CFTR expression by the intestinal epithelium during infection. CFTR protein initially present in the epithelial cell cytoplasm was rapidly trafficked to the plasma membrane following exposure to live serovar Typhi or bacterial extracts. CFTR-dependent bacterial uptake by epithelial cells increased (>100-fold) following CFTR redistribution. The bacterial factor which triggers CFTR redistribution is heat and protease sensitive. These data suggest that serovar Typhi induces intestinal epithelial cells to increase membrane CFTR levels, leading to enhanced bacterial ingestion and submucosal translocation. This could be a key, early step in the infectious process leading to typhoid fever. PMID:12379722

  16. Accepted: 2008-11-05Delivery and immunologic efficacy of CpG ODN targeting B lymphocytes of umbilical cord blood by CD40 ligand-receptor-mediated carrier%CD40配体-受体载体介导的CpG ODN靶向脐血B淋巴细胞的特异传递及其免疫效应

    Institute of Scientific and Technical Information of China (English)

    曾慧兰; 蒋建伟; 郑梅珍; 古晨; 韩新爱; 曾耀英; 狄静芳; 严玉霞

    2009-01-01

    cells and degradation by nuclease blocks its clinical application. OBJECTIVE: To explore the specific delivery and its immunologic efficacy of CpG ODN targeting B lymphocytes of umbilical cord blood by CD40 ligand-receptor-mediated carrier system. DESIGN, TIME AND SETTING: An observation and control experiment was performed at the Department of Hematology, and Department of Pediatric, the First Affiliated Hospital of Jinan University from April 2004 to October 2007. MATERIALS: Fresh umbilical cord blood with heparin was obtained from healthy, natal infant. Informed consent was obtained from his parents, and the experiment was approved by the hospital Ethics Committee. METHODS: CD40 ligand (CD40L)-EDC-PLL-CpG ODN conjugated complex was prepared. Mononuclear cells (MNCs) from umbilical cord blood were co-cultured with conjugated complexes. Uptake rate, mean fluorescence intensity of FAM marked CpG ODN, expressions of MNCs, proliferations of lymphocytes and the IgG levels of culture supematants were detected by flow cytometry, fluorescence techniques, MTT assay and ELISA, respectively. MAIN OUTCOME MEASURES: The uptake rate, the mean fluorescence intensity of CpG ODN by MNCs, subgroups and proliferations of lymphocytes, and IgG levels of culture supematants. RESULTS: Compared to the pure CpG ODN group, the uptake rate of the conjugated complexes group was higher (98%), the peak level of up-taking occurred earlier, and intracellular fluorescence intensity maintained much more stable. Expressions of CD19+, CD22+, and CD20+ was increased, A value and IgG levels in supematants were all higher than that of the control group. CONCLUSION: CD40 tigand-receptor-mediated carrier system is helpful for CpG ODN delivery targeting to B lymphocyte, enhancing its immunological efficiency.

  17. 胖Zucker大鼠肠系膜动脉多巴胺D1受体介导的血管舒张功能受损及其机制%Impaired dopamine D1 receptor-mediated vasorelaxation of mesenteric arteries in obese Zucker rats and its underlying mechanisms

    Institute of Scientific and Technical Information of China (English)

    符金娟; 韩愈; 王震; 关蔚蔚; 刘渔凯; 杨迪; 黄河飞; 杨素菲; 曾春雨

    2014-01-01

    目的 观察多巴胺D1受体激动剂Fenoldopam介导的血管舒张反应性在胖、瘦Zucker大鼠中的差异.方法 取12~14周健康雄性胖、瘦Zucker大鼠(n=12),采用鼠尾动脉无创测压法测定血压;采用离体微血管张力测定系统,观察雄性胖、瘦Zucker大鼠肠系膜三级动脉在内皮完整与去除后,Fenoldopam(1×10-8~3×10-6 mol/L)对苯肾上腺素(PHE,1×10-5 mol/L)预收缩血管的舒张作用.用多巴胺D1受体拮抗剂SCH23390(10-7 mol/L)预孵育Zucker大鼠肠系膜动脉30 min,观察Fenoldopam通过多巴胺D1受体舒张血管的特异性.采用蛋白免疫印迹法测定胖、瘦Zucker大鼠肠系膜组织多巴胺D1受体表达量的差异.结果 与瘦Zucker大鼠相比,胖Zucker大鼠的血压增高.在Fenoldopam 3×10-6mol/L时,瘦Zucker大鼠肠系膜动脉的舒张效应明显强于胖Zucker大鼠[(63.43±13.79)%比(20.75±8.60)%,P<0.01].去内皮前后,胖、瘦Zucker大鼠肠系膜动脉对Fenoldopam的舒张效应比较,差异无统计学意义(均P>0.05).SCH23390可以拮抗Fenoldopam对胖、瘦Zucker大鼠血管的舒张效应.蛋白免疫印迹结果显示,瘦Zucker大鼠肠系膜组织多巴胺D1受体表达量高于胖Zucker大鼠[(1.26±0.04)%比(0.74±0.06)%,P<0.01].结论 与瘦Zucker大鼠相比,胖Zucker大鼠血压增高;增高的血压可能与肠系膜动脉多巴胺D1受体表达量下降引起的Fenoldopam的血管舒张效应下降有关.%Objective To investigate the difference of dopamine D1 receptor-mediated vasorelaxation of mesenteric arteries between obese and lean Zucker rats,as well as its underlying mechanisms.Methods The blood pressures of obese and lean Zucker rats (12-14 weeks) were measured at tail artery (n=12).In an in-vitro microvascular tension measurement system,the relaxation effect of Fenoldopam (1 × 10-8 to 3 × 10-6 mol/L) on mesenteric arteries from all rats,with or without intact endothelium,was evaluated in a setting of phenylephedrine (PHE,1

  18. A new role for follicle-stimulating hormone in the regulation of calcium flux in Sertoli cells: Inhibition of Na+/Ca++ exchange

    International Nuclear Information System (INIS)

    Elucidation of mechanisms regulating intracellular calcium levels in steroidogenic tissues is important for understanding control of cellular function. We have previously described FSH receptor-mediated flux of 45Ca++ into cultured rat Sertoli cells and receptor-enriched proteoliposomes via voltage-sensitive and voltage-independent calcium channels. In the present study, we report heretofore unrecognized inhibitory effects of FSH on Na+/Ca++ exchange in these two systems. An outwardly directed Na+ gradient, developed by preincubating Sertoli cell monolayers in buffer made hypertonic with NaCl, resulted in uptake of 45Ca++ that was unaffected by calcium channel blocking agents, ruthenium red or methoxyverapamil, but was enhanced by ouabain, a specific inhibitor of Na+/K(+)-ATPase. Sodium-dependent 45Ca++ flux into Sertoli cells was inhibited in a concentration-related manner by increased extracellular Na+ (up to 135 mM). FSH consistently and reproducibly (28.9 +/- 3.8%, 10 separate assays) reduced sodium-dependent 45Ca++ influx in the absence or presence of ouabain. A lesser effect on Na+/Ca++ exchange was seen when Li+ replaced Na+ in the preincubation buffer, and a marked reduction occurred when Sertoli cells were incubated in buffer containing KCl, presumably due to membrane depolarization. FSH-sensitive Na+/45Ca++ exchange was also observed when using FSH receptor-enriched proteoliposomes. Our earlier calcium channel studies indicated that FSH affects Ca++ entry into Sertoli cells via a receptor-mediated process. The results reported here demonstrate that the interaction of FSH with its receptor is associated with changes in Na+/Ca++ exchange as well, and suggest that this activity may also be involved in regulating intracellular free Ca++ levels in the Sertoli cell

  19. Telomerase Regulation

    OpenAIRE

    Cifuentes-Rojas, Catherine; Dorothy E Shippen

    2011-01-01

    The intimate connection between telomerase regulation and human disease is now well established. The molecular basis for telomerase regulation is highly complex and entails multiple layers of control. While the major target of enzyme regulation is the catalytic subunit TERT, the RNA subunit of telomerase is also implicated in telomerase control. In addition, alterations in gene dosage and alternative isoforms of core telomerase components have been described. Finally, telomerase localization,...

  20. ERK1/2 and p38 kinases are important regulators in P2Y receptor-mediated prostate cancer invasion%ERK1/2 及p38通路调节P2Y受体介导的前列腺癌细胞体外侵袭

    Institute of Scientific and Technical Information of China (English)

    陈玲; 贺慧颖; 李红梅; 由江峰; 衡万杰; 李燕; 方伟岗

    2005-01-01

    目的探讨细胞外信号调节激酶(ERK1/2)及p38激酶在P2Y嘌呤受体活化介导的前列腺癌细胞体外侵袭中的作用.方法以脂质体法将负显性MAPK激酶1 (KA-MEK1) 及野生型p38磷酸酶(MKP-5)转染人前列腺癌细胞PC-3亚系1E8(高转移)和2B4(不转移)细胞,以 Western印迹法检测细胞经P2Y嘌呤受体激动剂ATP刺激后ERK1/2及p38活化情况,并用体外侵袭实验检测在P2Y受体介导的前列腺癌细胞体外侵袭效应中ERK1/2 及p38通路所起的作用.结果 ATP可以激活ERK1/2 及p38通路并促进前列腺癌细胞体外侵袭,这种侵袭促进效应可以分别被MEK1抑制剂PD98059及p38抑制剂SB203580所抑制.转染KA-MEK1及MKP-5使侵袭细胞数分别降低约40%及60%. 如果加入抑制剂同时抑制ERK1/2及p38通路,细胞的侵袭能力被抑制约76%.结论 ERK1/2及p38通路在P2Y嘌呤受体活化所介导的前列腺癌细胞侵袭中起重要作用.

  1. Regulating Transplants

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Legislation to determine brain death is viewed as essential in controlling the organ transplant industry Organ transplant represents a very sensitive and complicated issue. Experts say the temporary administrative regulations recently promulgated by the Central Government are an important step, but relevant laws and regulations must follow. Among these, the

  2. FLIP the Switch: Regulation of Apoptosis and Necroptosis by cFLIP

    Directory of Open Access Journals (Sweden)

    Yuichi Tsuchiya

    2015-12-01

    Full Text Available cFLIP (cellular FLICE-like inhibitory protein is structurally related to caspase-8 but lacks proteolytic activity due to multiple amino acid substitutions of catalytically important residues. cFLIP protein is evolutionarily conserved and expressed as three functionally different isoforms in humans (cFLIPL, cFLIPS, and cFLIPR. cFLIP controls not only the classical death receptor-mediated extrinsic apoptosis pathway, but also the non-conventional pattern recognition receptor-dependent apoptotic pathway. In addition, cFLIP regulates the formation of the death receptor-independent apoptotic platform named the ripoptosome. Moreover, recent studies have revealed that cFLIP is also involved in a non-apoptotic cell death pathway known as programmed necrosis or necroptosis. These functions of cFLIP are strictly controlled in an isoform-, concentration- and tissue-specific manner, and the ubiquitin-proteasome system plays an important role in regulating the stability of cFLIP. In this review, we summarize the current scientific findings from biochemical analyses, cell biological studies, mathematical modeling, and gene-manipulated mice models to illustrate the critical role of cFLIP as a switch to determine the destiny of cells among survival, apoptosis, and necroptosis.

  3. Mechanisms by which the orexigen NPY regulates anorexigenic α-MSH and TRH.

    Science.gov (United States)

    Cyr, Nicole E; Toorie, Anika M; Steger, Jennifer S; Sochat, Matthew M; Hyner, Samantha; Perello, Mario; Stuart, Ronald; Nillni, Eduardo A

    2013-03-15

    Protein posttranslational processing is a cellular mechanism fundamental to the generation of bioactive peptides, including the anorectic α-melanocyte-stimulating hormone (α-MSH) and thyrotropin-releasing hormone (TRH) peptides produced in the hypothalamic arcuate (ARC) and paraventricular (PVN) nuclei, respectively. Neuropeptide Y (NPY) promotes positive energy balance in part by suppressing α-MSH and TRH. The mechanism by which NPY regulates α-MSH output, however, is not well understood. Our results reveal that NPY inhibited the posttranslational processing of α-MSH's inactive precursor proopiomelanocortin (POMC) by decreasing the prohormone convertase-2 (PC2). We also found that early growth response protein-1 (Egr-1) and NPY-Y1 receptors mediated the NPY-induced decrease in PC2. NPY given intra-PVN also decreased PC2 in PVN samples, suggesting a reduction in PC2-mediated pro-TRH processing. In addition, NPY attenuated the α-MSH-induced increase in TRH production by two mechanisms. First, NPY decreased α-MSH-induced CREB phosphorylation, which normally enhances TRH transcription. Second, NPY decreased the amount of α-MSH in the PVN. Collectively, these results underscore the significance of the interaction between NPY and α-MSH in the central regulation of energy balance and indicate that posttranslational processing is a mechanism that plays a specific role in this interaction.

  4. The mechanism of functional up-regulation of P2X3 receptors of trigeminal sensory neurons in a genetic mouse model of familial hemiplegic migraine type 1 (FHM-1.

    Directory of Open Access Journals (Sweden)

    Swathi K Hullugundi

    Full Text Available A knock-in (KI mouse model of FHM-1 expressing the R192Q missense mutation of the Cacna1a gene coding for the α1 subunit of CaV2.1 channels shows, at the level of the trigeminal ganglion, selective functional up-regulation of ATP -gated P2X3 receptors of sensory neurons that convey nociceptive signals to the brainstem. Why P2X3 receptors are constitutively more responsive, however, remains unclear as their membrane expression and TRPV1 nociceptor activity are the same as in wildtype (WT neurons. Using primary cultures of WT or KI trigeminal ganglia, we investigated whether soluble compounds that may contribute to initiating (or maintaining migraine attacks, such as TNFα, CGRP, and BDNF, might be responsible for increasing P2X3 receptor responses. Exogenous application of TNFα potentiated P2X3 receptor-mediated currents of WT but not of KI neurons, most of which expressed both the P2X3 receptor and the TNFα receptor TNFR2. However, sustained TNFα neutralization failed to change WT or KI P2X3 receptor currents. This suggests that endogenous TNFα does not regulate P2X3 receptor responses. Nonetheless, on cultures made from both genotypes, exogenous TNFα enhanced TRPV1 receptor-mediated currents expressed by a few neurons, suggesting transient amplification of TRPV1 nociceptor responses. CGRP increased P2X3 receptor currents only in WT cultures, although prolonged CGRP receptor antagonism or BDNF neutralization reduced KI currents to WT levels. Our data suggest that, in KI trigeminal ganglion cultures, constitutive up-regulation of P2X3 receptors probably is already maximal and is apparently contributed by basal CGRP and BDNF levels, thereby rendering these neurons more responsive to extracellular ATP.

  5. NOISE REGULATION

    OpenAIRE

    Cristina Voican; Constantin Stanescu

    2012-01-01

    Noise regulation includes statutes or guidelines relating to sound transmission established by national, state or provincial and municipal levels of government. After the watershed passage of the United States Noise Control Act of 1972, other local and state governments passed further regulations. Although the UK and Japan enacted national laws in 1960 and 1967 respectively, these laws were not at all comprehensive or fully enforceable as to address generally rising ambient noise, enforceable...

  6. Up-regulation of striatal adenosine A(2A) receptors with iron deficiency in rats: effects on locomotion and cortico-striatal neurotransmission.

    Science.gov (United States)

    Quiroz, César; Pearson, Virginia; Gulyani, Seema; Allen, Richard; Earley, Christopher; Ferré, Sergi

    2010-07-01

    Brain iron deficiency leads to altered dopaminergic function in experimental animals, which can provide a mechanistic explanation for iron deficiency-related human sensory-motor disorders, such as Restless Legs Syndrome (RLS). However, mechanisms linking both conditions have not been determined. Considering the strong modulation exerted by adenosine on dopamine signaling, one connection could involve changes in adenosine receptor expression or function. In the striatum, presynaptic A(2A) receptors are localized in glutamatergic terminals contacting GABAergic dynorphinergic neurons and their function can be analyzed by the ability of A(2A) receptor antagonists to block the motor output induced by cortical electrical stimulation. Postsynaptic A(2A) receptors are localized in the dendritic field of GABAergic enkephalinergic neurons and their function can be analyzed by studying the ability of A(2A) receptor antagonists to produce locomotor activity and to counteract striatal ERK1/2 phosphorylation induced by cortical electrical stimulation. Increased density of striatal A(2A) receptors was found in rats fed during 3 weeks with an iron-deficient diet during the post-weaning period. In iron-deficient rats, the selective A(2A) receptor antagonist MSX-3, at doses of 1 and 3 mg/kg, was more effective at blocking motor output induced by cortical electrical stimulation (presynaptic A(2A) receptor-mediated effect) and at enhancing locomotor activation and blocking striatal ERK phosphorylation induced by cortical electrical stimulation (postsynaptic A(2A) receptor-mediated effects). These results indicate that brain iron deficiency induces a functional up-regulation of both striatal pre- and postsynaptic A(2A) receptor, which could be involved in sensory-motor disorders associated with iron deficiency such as RLS.

  7. NORM regulations

    Energy Technology Data Exchange (ETDEWEB)

    Gray, P. [ed.

    1997-02-01

    The author reviews the question of regulation for naturally occuring radioactive material (NORM), and the factors that have made this a more prominent concern today. Past practices have been very relaxed, and have often involved very poor records, the involvment of contractors, and the disposition of contaminated equipment back into commercial service. The rationale behind the establishment of regulations is to provide worker protection, to exempt low risk materials, to aid in scrap recycling, to provide direction for remediation and to examine disposal options. The author reviews existing regulations at federal and state levels, impending legislation, and touches on the issue of site remediation and potential liabilities affecting the release of sites contaminated by NORM.

  8. Sexual dimorphism in adrenergic regulation of hepatic glycogenolysis

    Energy Technology Data Exchange (ETDEWEB)

    Studer, R.K.

    1987-04-01

    The total phosphorylase a plus b of hepatocytes isolated from females and incubated in the absence or presence of estradiol and progesterone at concentrations found in vivo does not vary during the estrous cycle. However, there is a slight but significant influence of the estrous cycle on basal and epinephrine-stimulated phosphorylase a activity, with a nadir being seen on diestrus. The relative contributions of the ..cap alpha..- and ..beta..-mediated pathways to phosphorylase a activation do not vary with the estrous cycle but are constant at 75 and 56%, respectively, of the response to 5 x 10/sup -8/ M epinephrine. When the epinephrine-stimulated glucose release from glycogen stores in cells from females and males is compared, the release from the female is greater than that from the male, while the ..cap alpha..-receptor-mediated stimulation in the female is comparable with that in the male. The epinephrine-stimulated increase in cytostolic free calcium (Ca/sub i/) is greater in the male than the female at 10/sup -6/ M but greater in the female than the male at 5 x 10/sup -9/ M. The changes in Ca/sub i/ are equivalent at intermediate epinephrine concentrations. When considered with the prior analysis of /sup 45/Ca efflux after adrenergic stimulation, this suggests there may be a sexual dimorphism in hepatocyte calcium transport systems. The glucose release for a given increase in Ca/sub i/ is greater in the female than the male probably due to the concomitant action of the ..beta..-mediated increase in cAMP and the ..cap alpha..-mediated increase in Ca/sub i/. This supports the conclusion that the ..beta..-mediated component does make a significant contribution to the catecholamine regulation of glycogenolysis in hepatocytes from adult female rats.

  9. 叶酸受体新技术及细胞学检查对宫颈癌筛查应用价值的评估%Evaluation of the application of folate receptor mediated (FRD) multifunctional acetic acid white solution inspection with liquid based cytology screening for cervical cancer

    Institute of Scientific and Technical Information of China (English)

    邓翠; 康佳丽; 蒋文燕; 聂妙玲; 黄晓晖

    2014-01-01

    Objective To explore the folate receptor mediated (FRD) check and multi-function acetic acid white solution liquid based cervical cytology (TCT) application value in cervical cancer screening.Methods A total of 602 cases of patients was tested with FRD multi-function acetic acid white solution check,and TCT and cervical biopsy pathology examination.With the used of histopathological results as the gold standard,FRD multi-function acetic acid white analysis was compared with the TCT screening inspection results.Results For a total 602 patients with TCT screening,the positive rate was 21.8% (131/602),including 36 cases of CIN Ⅰ level,41 cases of CIN Ⅱ level,24 cases of CIN Ⅲ level,and 30 cases of cervical invasive carcinoma.For the FRD multifunction white acetate solution screening,its positive rate was 23.8% (143/602).No statistically significant difference was found between TCT and FRD screening (P > 0.05).The missed diagnosis rate of FRD multi-function white acetate solution screening was 2.6% in inflammation,and 21.1% in cervical invasive cancer,and 3.8 % in CIN.The missed diagnosis rate of TCT screening was 7.2% in inflammation,5.3% in CIN Ⅰ,4.9% in CIN Ⅱ,and 58.6% in CIN Ⅲ]; whereas,its detection coincidence rate was 100% in squamous cells carcinoma (SCC) and adenocarcinoma (AC).FRD multi-function acetic acid white solution screening had a sensitivity 80.92%,specificity 92.14%,positive predictive value 74.13%,and negative predictive value 95.59%.TCT examination had a sensitivity 90.84%,specificity 90.23%,positive predictive value 72.12%,and negative predictive value 97.25%.No significant difference was found between FRD and TCT methods (P > 0.05).Conclusions FRD and TCT methods were both efficient in screening and evaluation for cervical lesions and cervical cancer.Because FRD method is limited in the deep tube for examination of cervical lesions; it cannot completely replace the TCT examination

  10. The Lipid-Modifying Enzyme SMPDL3B Negatively Regulates Innate Immunity

    Directory of Open Access Journals (Sweden)

    Leonhard X. Heinz

    2015-06-01

    Full Text Available Lipid metabolism and receptor-mediated signaling are highly intertwined processes that cooperate to fulfill cellular functions and safeguard cellular homeostasis. Activation of Toll-like receptors (TLRs leads to a complex cellular response, orchestrating a diverse range of inflammatory events that need to be tightly controlled. Here, we identified the GPI-anchored Sphingomyelin Phosphodiesterase, Acid-Like 3B (SMPDL3B in a mass spectrometry screening campaign for membrane proteins co-purifying with TLRs. Deficiency of Smpdl3b in macrophages enhanced responsiveness to TLR stimulation and profoundly changed the cellular lipid composition and membrane fluidity. Increased cellular responses could be reverted by re-introducing affected ceramides, functionally linking membrane lipid composition and innate immune signaling. Finally, Smpdl3b-deficient mice displayed an intensified inflammatory response in TLR-dependent peritonitis models, establishing its negative regulatory role in vivo. Taken together, our results identify the membrane-modulating enzyme SMPDL3B as a negative regulator of TLR signaling that functions at the interface of membrane biology and innate immunity.

  11. Glucocorticoid regulation of brain-derived neurotrophic factor: relevance to hippocampal structural and functional plasticity.

    Science.gov (United States)

    Suri, D; Vaidya, V A

    2013-06-01

    Glucocorticoids serve as key stress response hormones that facilitate stress coping. However, sustained glucocorticoid exposure is associated with adverse consequences on the brain, in particular within the hippocampus. Chronic glucocorticoid exposure evokes neuronal cell damage and dendritic atrophy, reduces hippocampal neurogenesis and impairs synaptic plasticity. Glucocorticoids also alter expression and signaling of the neurotrophin, brain-derived neurotrophic factor (BDNF). Since BDNF is known to promote neuroplasticity, enhance cell survival, increase hippocampal neurogenesis and cellular excitability, it has been hypothesized that specific adverse effects of glucocorticoids may be mediated by attenuating BDNF expression and signaling. The purpose of this review is to summarize the current state of literature examining the influence of glucocorticoids on BDNF, and to address whether specific effects of glucocorticoids arise through perturbation of BDNF signaling. We integrate evidence of glucocorticoid regulation of BDNF at multiple levels, spanning from the well-documented glucocorticoid-induced changes in BDNF mRNA to studies examining alterations in BDNF receptor-mediated signaling. Further, we delineate potential lines of future investigation to address hitherto unexplored aspects of the influence of glucocorticoids on BDNF. Finally, we discuss the current understanding of the contribution of BDNF to the modulation of structural and functional plasticity by glucocorticoids, in particular in the context of the hippocampus. Understanding the mechanistic crosstalk between glucocorticoids and BDNF holds promise for the identification of potential therapeutic targets for disorders associated with the dysfunction of stress hormone pathways.

  12. Role of mitogen-activated protein kinases in endothelin ETB receptor up-regulation after organ culture of rat mesenteric artery

    DEFF Research Database (Denmark)

    Uddman, Erik; Henriksson, Marie; Eskesen, Karen;

    2003-01-01

    Organ culture of isolated arteries results in increased levels of endothelin ET(B) (ET(B)) receptor mRNA and in enhanced ET(B) receptor mediated contraction. The present study was designed to pinpoint the mitogen-activated protein kinase (MAPK) subtype involved in up-regulation of ET(B) receptors...... after organ culture of rat mesenteric arteries. Western blot and selective antibodies towards constitutional and phosphorylated MAPKs revealed the appearance of phosphorylated MAPK of the extracellular signal-regulated kinases (ERK) 1/2 type at 3 h of organ culture. The functional ET(B) receptor and its...... mRNA expression were up-regulated after 24 h of organ culture. Following incubation with the MEK 1/2 specific inhibitor SB408039 or the raf inhibitor SB386023b the up-regulation was attenuated both for ET(B) receptor responses and in ET(B) receptor mRNA expression in the vessel segments. Neither...

  13. Nuclear regulation

    International Nuclear Information System (INIS)

    Today, 112 nuclear power plants, 22 facilities that support these plants, 54 reactors used in research, and approximately 23,000 organizations hold licenses from either the Nuclear Regulator Commission or various states to use radioactive material; other facilities are operated by various government agencies. Eventually most of these facilities will be decommissioned, which involves removing the radioactive material and terminating the license. NRC needs to ensure that licensees appropriately decontaminate their facilities because, under current regulations, NRC cannot specifically require additional cleanup once it terminates a license. This paper presents a GAO report on NRC's decommissioning procedures. In two of eight cases GAO reviewed, NRC fully or partially released sites for unrestricted use where radioactive contamination was higher than its guidelines allowed; in the other cases, NRC's information was inadequate or incomplete. Further, NRC lacks information on the types and amounts of radioactive waste buried on-site. At five sites reviewed by GAO, groundwater has been found to be contaminated by radioactive waste

  14. Cross-regulation between colocalized nicotinic acetylcholine and 5-HT3 serotonin receptors on presynaptic nerve terminals

    Institute of Scientific and Technical Information of China (English)

    John J DOUGHERTY; Robert A NICHOLS

    2009-01-01

    Aim: Substantial colocalization of functionally independent a4 nicotinic acetylcholine receptors and 5-HT3 serotonin receptors on presynaptic terminals has been observed in brain. The present study was aimed at addressing whether nicotinic acetylcholine receptors and 5-HT3 serotonin receptors interact on the same presynaptic terminal, suggesting a convergence of cholinergic and serotonergic regulation.Methods: Ca2+ responses in individual, isolated nerve endings purified from rat striatum were measured using confocal imaging.Results: Application of 500 nmol/L nicotine following sustained stimulation with the highly selective 5-HT3 receptor agonist m-chlorophenylbiguanide at 100 nmol/L resulted in markedly reduced Ca2* responses (28% of control) in only those striatal nerve endings that originally responded to m-chlorophenylbiguanide. The cross-regulation developed over several minutes. Presynaptic nerve endings that had not responded to m-chlorophenylbiguanide, indicating that 5-HT3 receptors were not present, displayed typical responses to nicotine. Application of m-chlorophenylbiguanide following sustained stimulation with nicotine resulted in partially attenuated Ca2* responses (49% of control). Application of m-chlorophenylbiguanide following sustained stimulation with m-chlorophenylbiguanide also resulted in a strong attenuation of Ca2+ responses (12% of control), whereas nicotine-induced Ca2t responses following sustained stimulation with nicotine were not significantly different from control.Conclusion: These results indicate that the presynaptic Ca2+ increases evoked by either 5-HT, receptor or nicotinic acetylcholine receptor activation regulate subsequent responses to 5-HT3 receptor activation, but that only 5-HT3 receptors cross-regulate subsequent nicotinic acetylcholine receptor-mediated responses. The findings suggest a specific interaction between the two receptor systems in the same striatal nerve terminal, likely involving Ca2+-dependent

  15. Lipid rafts as major platforms for signaling regulation in cancer.

    Science.gov (United States)

    Mollinedo, Faustino; Gajate, Consuelo

    2015-01-01

    Cell signaling does not apparently occur randomly over the cell surface, but it seems to be integrated very often into cholesterol-rich membrane domains, termed lipid rafts. Membrane lipid rafts are highly ordered membrane domains that are enriched in cholesterol, sphingolipids and gangliosides, and behave as major modulators of membrane geometry, lateral movement of molecules, traffic and signal transduction. Because the lipid and protein composition of membrane rafts differs from that of the surrounding membrane, they provide an additional level of compartmentalization, serving as sorting platforms and hubs for signal transduction proteins. A wide number of signal transduction processes related to cell adhesion, migration, as well as to cell survival and proliferation, which play major roles in cancer development and progression, are dependent on lipid rafts. Despite lipid rafts harbor mainly critical survival signaling pathways, including insulin-like growth factor I (IGF-I)/phosphatidylinositol 3-kinase (PI3K)/Akt signaling, recent evidence suggests that these membrane domains can also house death receptor-mediated apoptotic signaling. Recruitment of this death receptor signaling pathway in membrane rafts can be pharmacologically modulated, thus opening up the possibility to regulate cell demise with a therapeutic use. The synthetic ether phospholipid edelfosine shows a high affinity for cholesterol and accumulates in lipid rafts in a number of malignant hematological cells, leading to an efficient in vitro and in vivo antitumor activity by inducing translocation of death receptors and downstream signaling molecules to these membrane domains. Additional antitumor drugs have also been shown to act, at least in part, by recruiting death receptors in lipid rafts. The partition of death receptors together with downstream apoptotic signaling molecules in membrane rafts has led us to postulate the concept of a special liquid-ordered membrane platform coined as

  16. Lipid rafts as major platforms for signaling regulation in cancer.

    Science.gov (United States)

    Mollinedo, Faustino; Gajate, Consuelo

    2015-01-01

    Cell signaling does not apparently occur randomly over the cell surface, but it seems to be integrated very often into cholesterol-rich membrane domains, termed lipid rafts. Membrane lipid rafts are highly ordered membrane domains that are enriched in cholesterol, sphingolipids and gangliosides, and behave as major modulators of membrane geometry, lateral movement of molecules, traffic and signal transduction. Because the lipid and protein composition of membrane rafts differs from that of the surrounding membrane, they provide an additional level of compartmentalization, serving as sorting platforms and hubs for signal transduction proteins. A wide number of signal transduction processes related to cell adhesion, migration, as well as to cell survival and proliferation, which play major roles in cancer development and progression, are dependent on lipid rafts. Despite lipid rafts harbor mainly critical survival signaling pathways, including insulin-like growth factor I (IGF-I)/phosphatidylinositol 3-kinase (PI3K)/Akt signaling, recent evidence suggests that these membrane domains can also house death receptor-mediated apoptotic signaling. Recruitment of this death receptor signaling pathway in membrane rafts can be pharmacologically modulated, thus opening up the possibility to regulate cell demise with a therapeutic use. The synthetic ether phospholipid edelfosine shows a high affinity for cholesterol and accumulates in lipid rafts in a number of malignant hematological cells, leading to an efficient in vitro and in vivo antitumor activity by inducing translocation of death receptors and downstream signaling molecules to these membrane domains. Additional antitumor drugs have also been shown to act, at least in part, by recruiting death receptors in lipid rafts. The partition of death receptors together with downstream apoptotic signaling molecules in membrane rafts has led us to postulate the concept of a special liquid-ordered membrane platform coined as

  17. The neural cell adhesion molecule-derived peptide, FGL, attenuates lipopolysaccharide-induced changes in glia in a CD200-dependent manner

    DEFF Research Database (Denmark)

    Cox, F F; Berezin, V; Bock, E;

    2013-01-01

    200-deficient mice and preincubated with FGL prior to stimulation with lipopolysaccharide (LPS). Cells were assessed for mRNA expression of markers of microglial activation, CD11b, CD40 and intercellular adhesion molecule 1 (ICAM-1) and also the inflammatory cytokines, interleukin (IL)-1β, IL-6...

  18. Folate Receptor β Regulates Integrin CD11b/CD18 Adhesion of a Macrophage Subset to Collagen.

    Science.gov (United States)

    Machacek, Christian; Supper, Verena; Leksa, Vladimir; Mitulovic, Goran; Spittler, Andreas; Drbal, Karel; Suchanek, Miloslav; Ohradanova-Repic, Anna; Stockinger, Hannes

    2016-09-15

    Folate, also known as vitamin B9, is necessary for essential cellular functions such as DNA synthesis, repair, and methylation. It is supplied to the cell via several transporters and receptors, including folate receptor (FR) β, a GPI-anchored protein belonging to the folate receptor family. As FRβ shows a restricted expression to cells of myeloid origin and only a subset of activated macrophages and placental cells have been shown to express functional FRβ, it represents a promising target for future therapeutic strategies. In this study, we performed affinity purification and mass spectrometric analysis of the protein microenvironment of FRβ in the plasma membrane of human FRβ(+) macrophages and FRβ-transduced monocytic THP-1 cells. In this manner, we identified a novel role of FRβ: that is, we report functional interactions of FRβ with receptors mediating cellular adhesion, in particular the CD11b/CD18 β2 integrin heterodimer complement receptor type 3/Mac-1. This interaction results in impeded adhesion of FRβ(+) human primary macrophages and THP-1 cells to collagen in comparison with their FRβ(-) counterparts. We further show that FRβ is only expressed by human macrophages when differentiated with M-CSF. These findings thus identify FRβ as a novel CD11b/CD18 regulator for trafficking and homing of a subset of macrophages on collagen. PMID:27534550

  19. Negative regulation of gamma-aminobutyric acid type A receptor on free calcium ion levels following facial nerve injury

    Institute of Scientific and Technical Information of China (English)

    Fugao Zhu; Dawei Sun; Yanqing Wang; Rui Zhou; Junfeng Wen; Xiuming Wan; Yanjun Wang; Banghua Liu

    2010-01-01

    Previous studies have demonstrated that muscarinic, and nicotinic receptors increase free Ca2+ levels in the facial nerve nucleus via various channels following facial nerve injury. However, intracellular Ca2+ overload can trigger either necrotic or apoptotic cell death. Gamma-aminobutyric acid (GABA), an important inhibitory neurotransmitter in the central nervous system, exists in the facial nerve nucleus. It is assumed that GABA negatively regulates free Ca2+ levels in the facial nerve nucleus. The present study investigated GABA type A (GABAA) receptor expression in the facial nerve nucleus in a rat model of facial nerve injury using immunohistochemistry and laser confocal microscopy, as well as the regulatory effects of GABAA receptor on nicotinic receptor response following facial nerve injury. Subunits α1, α3, α5, β1, β2, δ, and γ3 of GABAA receptors were expressed in the facial nerve nucleus following facial nerve injury. In addition, GABAA receptor expression significantly inhibited the increase in nicotinic receptor-mediated free Ca2+ levels in the facial nerve nucleus following facial nerve injury in a concentration-dependent fashion. These results suggest that GABAA receptors exhibit negative effects on nicotinic receptor responses following facial nerve injury.

  20. Lipid rafts and raft-mediated supramolecular entities in the regulation of CD95 death receptor apoptotic signaling.

    Science.gov (United States)

    Gajate, Consuelo; Mollinedo, Faustino

    2015-05-01

    Membrane lipid rafts are highly ordered membrane domains enriched in cholesterol, sphingolipids and gangliosides that have the property to segregate and concentrate proteins. Lipid and protein composition of lipid rafts differs from that of the surrounding membrane, thus providing sorting platforms and hubs for signal transduction molecules, including CD95 death receptor-mediated signaling. CD95 can be recruited to rafts in a reversible way through S-palmitoylation following activation of cells with its physiological cognate ligand as well as with a wide variety of inducers, including several antitumor drugs through ligand-independent intracellular mechanisms. CD95 translocation to rafts can be modulated pharmacologically, thus becoming a target for the treatment of apoptosis-defective diseases, such as cancer. CD95-mediated signaling largely depends on protein-protein interactions, and the recruitment and concentration of CD95 and distinct downstream apoptotic molecules in membrane raft domains, forming raft-based supramolecular entities that act as hubs for apoptotic signaling molecules, favors the generation and amplification of apoptotic signals. Efficient CD95-mediated apoptosis involves CD95 and raft internalization, as well as the involvement of different subcellular organelles. In this review, we briefly summarize and discuss the involvement of lipid rafts in the regulation of CD95-mediated apoptosis that may provide a new avenue for cancer therapy.

  1. Androgen regulation of adrenocorticotropin and corticosterone secretion in the male rat following novelty and foot shock stressors.

    Science.gov (United States)

    Handa, R J; Nunley, K M; Lorens, S A; Louie, J P; McGivern, R F; Bollnow, M R

    1994-01-01

    To examine mechanisms responsible for sex differences in hypothalamo-pituitary-adrenal (HPA) axis responsiveness to stress, we studied the role of androgens in the regulation of the adrenocorticotropin (ACTH) and corticosterone (CORT) responses to foot shock and novelty stressors in gonadectomized (GDX) or intact male F344 rats. Foot shock or exposure to a novel open field increased plasma ACTH and CORT, which was significantly greater in GDX vs. intacts. Testosterone (T) or dihydrotestosterone propionate (DHT) treatment of GDX animals returned poststress levels of ACTH and CORT to intact levels. Estrogen treatment of GDX males further increased poststress CORT secretion above GDX levels. There was no difference in the ACTH response of anterior pituitaries from intact, GDX, and GDX+DHT animals to CRF using an in vitro perifusion system. There were no differences in beta max or binding affinity of type I or II CORT receptors in the hypothalamus or hippocampus of intact, GDX, or GDX+DHT groups. These data demonstrate an effect of GDX on hormonal indices of stress. The increased response in GDX rats appears to be due to the release from androgen receptor mediated inhibition of the HPA axis. This inhibition by androgen is not due to changes in anterior pituitary sensitivity to CRH, nor to changes in type I or type II corticosteroid receptor concentrations. PMID:8140154

  2. High-pass filtering and dynamic gain regulation enhance vertical bursts transmission along the mossy fiber pathway of cerebellum

    Directory of Open Access Journals (Sweden)

    Jonathan Mapelli

    2010-05-01

    Full Text Available Signal elaboration in the cerebellum mossy fiber input pathway presents controversial aspects, especially concerning gain regulation and the spot-like (rather than beam-like appearance of granular-to-molecular layer transmission. By using voltage-sensitive dye (VSD imaging in rat cerebellar slices (Mapelli et al., 2010, we found that mossy fiber bursts optimally excited the granular layer above ~50 Hz and the overlaying molecular layer above ~100 Hz, thus generating a cascade of high-pass filters. NMDA receptors enhanced transmission in the granular, while GABA-A receptors depressed transmission in both the granular and molecular layer. Burst transmission gain was controlled through a dynamic frequency-dependent involvement of these receptors. Moreover, while high-frequency transmission was enhanced along vertical lines connecting the granular to molecular layer, no high-frequency enhancement was observed along the parallel fiber axis in the molecular layer. This was probably due to the stronger effect of Purkinje cell GABA-A receptor-mediated inhibition occurring along the parallel fibers than along the granule cell axon ascending branch. The consequent amplification of burst responses along vertical transmission lines could explain the spot-like activation of Purkinje cells observed following punctuate stimulation in vivo .

  3. The Ralstonia solanacearum pathogenicity regulator HrpB induces 3-hydroxy-oxindole synthesis.

    Science.gov (United States)

    Delaspre, Fabien; Nieto Peñalver, Carlos G; Saurel, Olivier; Kiefer, Patrick; Gras, Emmanuel; Milon, Alain; Boucher, Christian; Genin, Stéphane; Vorholt, Julia A

    2007-10-01

    The transcriptional activator HrpB of the bacterial wilt causing betaproteobacterium Ralstonia solanacearum represents a key regulator for pathogenicity. In particular, it drives expression of hrp genes encoding a type III secretion system (T3SS) as well as effector molecules for delivery into the host cytosol to promote disease. However, the HrpB regulon extends beyond this T3SS. We describe here an HrpB-activated operon of six genes that is responsible for the synthesis of a fluorescent isatin derivative of 149 Amu that we named HDF for HrpB-dependent factor and that we purified from culture supernatants. The structure of the labile molecule was solved by using NMR and CD spectroscopy to be (3S)-3-hydroxy-indolin-2-one and confirmed by its chemical synthesis and MS spectrometry. HDF was found to be present at 20 nM in wild-type cultures grown on minimal medium, and its synthesis increased 15-fold upon overproduction of HrpB, confirming that HrpB activates HDF synthesis. The addition of tryptophan significantly stimulated HDF biosynthesis and was shown to represent the precursor molecule for HDF synthesis. A search for the biological function of the molecule revealed that HDF induces acyl-homoserine lactone receptor-mediated reporter activity of the well studied LuxR transcriptional regulator of Vibrio fischeri. Thus, our results provide evidence that the specificity of acyl-homoserine lactone (acyl-HSL) receptors is clearly broader than previously considered. The failure to detect induction by HDF of the described endogenous quorum-sensing circuits of the pathogen points to a role in interfering with cell-cell signaling of rivalling bacteria. PMID:17890323

  4. Adaptive gene regulation in the Striatum of RGS9-deficient mice.

    Directory of Open Access Journals (Sweden)

    Kathy Busse

    Full Text Available BACKGROUND: RGS9-deficient mice show drug-induced dyskinesia but normal locomotor activity under unchallenged conditions. RESULTS: Genes related to Ca2+ signaling and their functions were regulated in RGS9-deficient mice. CONCLUSION: Changes in Ca2+ signaling that compensate for RGS9 loss-of-function can explain the normal locomotor activity in RGS9-deficient mice under unchallenged conditions. SIGNIFICANCE: Identified signaling components may represent novel targets in antidyskinetic therapy. The long splice variant of the regulator of G-protein signaling 9 (RGS9-2 is enriched in striatal medium spiny neurons and dampens dopamine D2 receptor signaling. Lack of RGS9-2 can promote while its overexpression prevents drug-induced dyskinesia. Other animal models of drug-induced dyskinesia rather pointed towards overactivity of dopamine receptor-mediated signaling. To evaluate changes in signaling pathways mRNA expression levels were determined and compared in wild-type and RGS9-deficient mice. Unexpectedly, expression levels of dopamine receptors were unchanged in RGS9-deficient mice, while several genes related to Ca2+ signaling and long-term depression were differentially expressed when compared to wild type animals. Detailed investigations at the protein level revealed hyperphosphorylation of DARPP32 at Thr34 and of ERK1/2 in striata of RGS9-deficient mice. Whole cell patch clamp recordings showed that spontaneous synaptic events are increased (frequency and size in RGS9-deficient mice while long-term depression is reduced in acute brain slices. These changes are compatible with a Ca2+-induced potentiation of dopamine receptor signaling which may contribute to the drug-induced dyskinesia in RGS9-deficient mice.

  5. Human neural progenitors express functional lysophospholipid receptors that regulate cell growth and morphology

    Directory of Open Access Journals (Sweden)

    Callihan Phillip

    2008-12-01

    Full Text Available Abstract Background Lysophospholipids regulate the morphology and growth of neurons, neural cell lines, and neural progenitors. A stable human neural progenitor cell line is not currently available in which to study the role of lysophospholipids in human neural development. We recently established a stable, adherent human embryonic stem cell-derived neuroepithelial (hES-NEP cell line which recapitulates morphological and phenotypic features of neural progenitor cells isolated from fetal tissue. The goal of this study was to determine if hES-NEP cells express functional lysophospholipid receptors, and if activation of these receptors mediates cellular responses critical for neural development. Results Our results demonstrate that Lysophosphatidic Acid (LPA and Sphingosine-1-phosphate (S1P receptors are functionally expressed in hES-NEP cells and are coupled to multiple cellular signaling pathways. We have shown that transcript levels for S1P1 receptor increased significantly in the transition from embryonic stem cell to hES-NEP. hES-NEP cells express LPA and S1P receptors coupled to Gi/o G-proteins that inhibit adenylyl cyclase and to Gq-like phospholipase C activity. LPA and S1P also induce p44/42 ERK MAP kinase phosphorylation in these cells and stimulate cell proliferation via Gi/o coupled receptors in an Epidermal Growth Factor Receptor (EGFR- and ERK-dependent pathway. In contrast, LPA and S1P stimulate transient cell rounding and aggregation that is independent of EGFR and ERK, but dependent on the Rho effector p160 ROCK. Conclusion Thus, lysophospholipids regulate neural progenitor growth and morphology through distinct mechanisms. These findings establish human ES cell-derived NEP cells as a model system for studying the role of lysophospholipids in neural progenitors.

  6. Prostaglandin E2 regulates melanocyte dendrite formation through activation of PKCζ

    International Nuclear Information System (INIS)

    Prostaglandins are lipid signaling intermediates released by keratinocytes in response to ultraviolet irradiation (UVR) in the skin. The main prostaglandin released following UVR is PGE2, a ligand for 4 related G-protein-coupled receptors (EP1, EP2, EP3 and EP4). Our previous work established that PGE2 stimulates melanocyte dendrite formation through activation of the EP1 and EP3 receptors. The purpose of the present report is to define the signaling intermediates involved in EP1- and EP3-dependent dendrite formation in human melanocytes. We recently showed that activation of the atypical PKCζ isoform stimulates melanocyte dendricity in response to treatment with lysophosphatidylcholine. We therefore examined the potential contribution of PKCζ activation on EP1- and EP3-dependent dendrite formation in melanocytes. Stimulation of the EP1 and EP3 receptors by selective agonists activated PKCζ, and inhibition of PKCζ activation abrogated EP1- and EP3-receptor-mediated melanocyte dendricity. Because of the importance of Rho-GTP binding proteins in the regulation of melanocyte dendricity, we also examined the effect of EP1 and EP3 receptor activation on Rac and Rho activity. Neither Rac nor Rho was activated upon treatment with EP1,3-receptor agonists. We show that melanocytes express only the EP3A1 isoform, but not the EP3B receptor isoform, previously associated with Rho activation, consistent with a lack of Rho stimulation by EP3 agonists. Our data suggest that PKCζ activation plays a predominant role in regulation of PGE2-dependent melanocyte dendricity

  7. A Targeted DNAzyme-Nanocomposite Probe Equipped with Built-in Zn2+ Arsenal for Combined Treatment of Gene Regulation and Drug Delivery

    Science.gov (United States)

    He, Zhi-Mei; Zhang, Peng-Hui; Li, Xin; Zhang, Jian-Rong; Zhu, Jun-Jie

    2016-01-01

    As catalytic nucleic acids, DNAzymes have been extensively used in the design of sensing platforms. However, their potentials as intelligent drug carriers for responsive drug release in gene therapy and chemotherapy were rarely explored. Herein, we report a dual-functional probe composed of gold nanoparticles (GNPs), catalytic Zn2+-dependent DNAzyme, anticancer drug doxorubicin (Dox), targeted AS1411 aptamer and acid-decomposable ZnO quantum dots (ZnO QDs) to achieve intracellular gene regulation and drug delivery in a controlled manner. By means of aptamer-guided targeting and receptor-mediated endocytosis, the probes were specifically internalized into the HeLa cells and trapped in the acidic endo-/lysosomes, where the ZnO QDs as the built-in Zn2+ arsenal were promptly dissolved to offer Zn2+, leading to the activation of DNAzyme to cleave the substrate strands, and subsequent drug release. Meanwhile, as designed, one part of the cleaved substrate, hybridized with the overexpressed miR-21 in the target cells, thereby declining its intracellular level. Taken together, the down-regulation of miR-21 has a synergistic effect with Dox to efficiently eradicate the cancer cells. Thus, the favorable biocompatibility, cancer cell specificity and combined treatment make the probe promising for therapy of multidrug-resistant cancer and in vivo application. PMID:26956167

  8. The Xanthomonas oryzae pv. oryzae PilZ Domain Proteins Function Differentially in Cyclic di-GMP Binding and Regulation of Virulence and Motility.

    Science.gov (United States)

    Yang, Fenghuan; Tian, Fang; Chen, Huamin; Hutchins, William; Yang, Ching-Hong; He, Chenyang

    2015-07-01

    The PilZ domain proteins have been demonstrated to be one of the major types of receptors mediating cyclic di-GMP (c-di-GMP) signaling pathways in several pathogenic bacteria. However, little is known about the function of PilZ domain proteins in c-di-GMP regulation of virulence in the bacterial blight pathogen of rice Xanthomonas oryzae pv. oryzae. Here, the roles of PilZ domain proteins PXO_00049 and PXO_02374 in c-di-GMP binding, regulation of virulence and motility, and subcellular localization were characterized in comparison with PXO_02715, identified previously as an interactor with the c-di-GMP receptor Filp to regulate virulence. The c-di-GMP binding motifs in the PilZ domains were conserved in PXO_00049 and PXO_02374 but were less well conserved in PXO_02715. PXO_00049 and PXO_02374 but not PXO_02715 proteins bound to c-di-GMP with high affinity in vitro, and the R(141) and R(10) residues in the PilZ domains of PXO_00049 and PXO_02374, respectively, were crucial for c-di-GMP binding. Gene deletion of PXO_00049 and PXO_02374 resulted in significant increases in virulence and hrp gene transcription, indicating their negative regulation of virulence via type III secretion system expression. All mutants showed significant changes in sliding motility but not exopolysaccharide production and biofilm formation. In trans expression of the full-length open reading frame (ORF) of each gene in the relevant mutants led to restoration of the phenotype to wild-type levels. Moreover, PXO_00049 and PXO_02374 displayed mainly multisite subcellular localizations, whereas PXO_02715 showed nonpolar distributions in the X. oryzae pv. oryzae cells. Therefore, this study demonstrated the different functions of the PilZ domain proteins in mediation of c-di-GMP regulation of virulence and motility in X. oryzae pv. oryzae.

  9. Short-chain fatty acids act as antiinflammatory mediators by regulating prostaglandin E_2 and cytokines

    Institute of Scientific and Technical Information of China (English)

    Mary Ann Cox; James Jackson; Michaela Stanton; Alberto Rojas-Triana; Loretta Bober; Maureen Laverty; Xiaoxin Yang; Feng Zhu; Jianjun Liu; Suke Wang; Frederick Monsma; Galya Vassileva; Maureen Maguire; Eric Gustafson; Marvin Bayne; Chuan-Chu Chou; Daniel Lundell; Chung-Her Jenh

    2009-01-01

    AIM: To investigate the effect of short-chain fatty acids(SCFAs) on production of prostaglandin E_2 (PGE_2),cytokines and chemokines in human monocytes.METHODS: Human neutrophils and monocytes were isolated from human whole blood by using 1-Step Polymorph and RosetteSep Human Monocyte Enrichment Cocktail, respectively. Human GPR41 and GPR43 mRNA expression was examined by quantitative realtimepolymerase chain reaction. The calcium flux assay was used to examine the biological activities of SCFAs in human neutrophils and monocytes. The effect of SCFAs on human monocytes and peripheral blood mononuclear cells (PBMC) was studied by measuring PGE_2, cytokines and chemokines in the supernatant.The effect of SCFAs in vivo was examined by intraplantar injection into rat paws.RESULTS: Human GPR43 is highly expressed in human neutrophils and monocytes. SCFAs induce robust calcium flux in human neutrophils, but not in human monocytes. In this study, we show that SCFAs can induce human monocyte release of PGE_2 and that this effect can be enhanced in the presence of lipopolysaccharide(LPS). In addition, we demonstrate that PGE_2 production induced by SCFA was inhibited by pertussis toxin, suggesting the involvement of a receptor-mediated mechanism. Furthermore, SCFAs can specifically inhibit constitutive monocyte chemotactic protein-1(MCP-1) production and LPS-induced interleukin-10(IL-10) production in human monocytes without affecting the secretion of other cytokines and chemokines examined. Similar activities were observed in human PBMC for the release of PGE_2, MCP-1 and IL-10 after SCFA treatment. In addition, SCFAs inhibit LPS-induced production of tumor necrosis factor-α and interferon-γ in human PBMC. Finally, we show that SCFAs and LPS can induce PGE_2 production in vivo by intraplantar injectioninto rat paws ( P < 0.01).CONCLUSION: SCFAs can have distinct antiinflammatory activities due to their regulation of PGE_2, cytokine and chemokine release from human immune

  10. Regulation of Calcium Channels and Exocytosis in Mouse Adrenal Chromaffin Cells by Prostaglandin EP3 Receptors

    Science.gov (United States)

    Jewell, Mark L.; Breyer, Richard M.

    2011-01-01

    Prostaglandin (PG) E2 controls numerous physiological functions through a family of cognate G protein-coupled receptors (EP1–EP4). Targeting specific EP receptors might be therapeutically useful and reduce side effects associated with nonsteroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors that block prostanoid synthesis. Systemic immune challenge and inflammatory cytokines have been shown to increase expression of the synthetic enzymes for PGE2 in the adrenal gland. Catecholamines and other hormones, released from adrenal chromaffin cells in response to Ca2+ influx through voltage-gated Ca2+ channels, play central roles in homeostatic function and the coordinated stress response. However, long-term elevation of circulating catecholamines contributes to the pathogenesis of hypertension and heart failure. Here, we investigated the EP receptor(s) and cellular mechanisms by which PGE2 might modulate chromaffin cell function. PGE2 did not alter resting intracellular [Ca2+] or the peak amplitude of nicotinic acetylcholine receptor currents, but it did inhibit CaV2 voltage-gated Ca2+ channel currents (ICa). This inhibition was voltage-dependent and mediated by pertussis toxin-sensitive G proteins, consistent with a direct Gβγ subunit-mediated mechanism common to other Gi/o-coupled receptors. mRNA for all four EP receptors was detected, but using selective pharmacological tools and EP receptor knockout mice, we demonstrated that EP3 receptors mediate the inhibition of ICa. Finally, changes in membrane capacitance showed that Ca2+-dependent exocytosis was reduced in parallel with ICa. To our knowledge, this is the first study of EP receptor signaling in mouse chromaffin cells and identifies a molecular mechanism for paracrine regulation of neuroendocrine function by PGE2. PMID:21383044

  11. Complex Regulation Pattern of IRF3 Activation Revealed by a Novel Dimerization Reporter System.

    Science.gov (United States)

    Wang, Zining; Ji, Jingyun; Peng, Di; Ma, Feng; Cheng, Genhong; Qin, F Xiao-Feng

    2016-05-15

    Induction of type I IFN (IFN-I) is essential for host antiviral immune responses. However, IFN-I also plays divergent roles in antibacterial immunity, persistent viral infections, autoimmune diseases, and tumorigenesis. IFN regulatory factor 3 (IRF3) is the master transcription factor that controls IFN-I production via phosphorylation-dependent dimerization in most cell types in response to viral infections and various innate stimuli by pathogen-associated molecular patterns (PAMPs). To monitor the dynamic process of IRF3 activation, we developed a novel IRF3 dimerization reporter based on bimolecular luminescence complementation (BiLC) techniques, termed the IRF3-BiLC reporter. Robust induction of luciferase activity of the IRF3-BiLC reporter was observed upon viral infection and PAMP stimulation with a broad dynamic range. Knockout of TANK-binding kinase 1, the critical upstream kinase of IRF3, as well as the mutation of serine 386, the essential phosphorylation site of IRF3, completely abolished the luciferase activity of IRF3-BiLC reporter, confirming the authenticity of IRF3 activation. Taken together, these results demonstrated that the IRF3-BiLC reporter is a highly specific, reliable, and sensitive system to measure IRF3 activity. Using this reporter system, we further observed that the temporal pattern and magnitude of IRF3 activation induced by various PAMPs are highly complex with distinct cell type-specific characteristics, and IRF3 dimerization is a direct regulatory node for IFN-α/β receptor-mediated feed-forward regulation and crosstalk with other pathways. Therefore, the IRF3-BiLC reporter has multiple potential applications, including mechanistic studies as well as the identification of novel compounds that can modulate IRF3 activation. PMID:27045107

  12. P2Y receptors of MDCK cells: epithelial cell regulation by extracellular nucleotides.

    Science.gov (United States)

    Insel, P A; Ostrom, R S; Zambon, A C; Hughes, R J; Balboa, M A; Shehnaz, D; Gregorian, C; Torres, B; Firestein, B L; Xing, M; Post, S R

    2001-04-01

    1. Madin-Darby canine kidney (MDCK) cells, a well- differentiated renal epithelial cell line derived from distal tubule/collecting duct, respond to extracellular nucleotides by altering ion flux and the production of arachidonic acid-derived products, in particular prostaglandin E2 (PGE2). Our work has defined the receptors and signalling events involved in such responses. 2. We have found evidence for expression of at least three P2Y receptor subtypes (P2Y1, P2Y2 and P2Y11) in MDCK-D1 cells, a subclone from parental MDCK. 3. These receptors appear to couple to increases in calcium and protein kinase C activity, probably via a Gq/G11-mediated activation of phospholipase C. 4. In addition, P2Y receptor activation can promote a prominent increase in cAMP. This includes both a P2Y2 receptor-mediated cyclo-oxygenase (COX)-dependent component and another COX-independent component mediated by other P2Y receptors. 5. We have documented that changing media in which cells are grown releases ATP and, in turn, activates P2Y receptors. Such release of ATP contributes in a major way to basal cAMP levels in these cells. 6. The data indicate that MDCK cells are a useful model to define the regulation of epithelial cells by extracellular nucleotides. Of particular note, spontaneous or stretch-induced release of ATP and subsequent activation of one or more P2Y receptors contributes to establishing the basal activity of signalling pathways. PMID:11339212

  13. Regulation of GABA Equilibrium Potential by mGluRs in Rat Hippocampal CA1 Neurons.

    Science.gov (United States)

    Yang, Bo; Rajput, Padmesh S; Kumar, Ujendra; Sastry, Bhagavatula R

    2015-01-01

    The equilibrium potential for GABA-A receptor mediated currents (EGABA) in neonatal central neurons is set at a relatively depolarized level, which is suggested to be caused by a low expression of K+/Cl- co-transporter (KCC2) but a relatively high expression of Na+-K+-Cl- cotransporter (NKCC1). Theta-burst stimulation (TBS) in stratum radiatum induces a negative shift in EGABA in juvenile hippocampal CA1 pyramidal neurons. In the current study, the effects of TBS on EGABA in neonatal and juvenile hippocampal CA1 neurons and the underlying mechanisms were examined. Metabotropic glutamate receptors (mGluRs) are suggested to modulate KCC2 and NKCC1 levels in cortical neurons. Therefore, the involvement of mGluRs in the regulation of KCC2 or NKCC1 activity, and thus EGABA, following TBS was also investigated. Whole-cell patch recordings were made from Wistar rat hippocampal CA1 pyramidal neurons, in a slice preparation. In neonates, TBS induces a positive shift in EGABA, which was prevented by NKCC1 antisense but not NKCC1 sense mRNA. (RS)-a-Methyl-4-carboxyphenylglycine (MCPG), a group I and II mGluR antagonist, blocked TBS-induced shifts in both juvenile and neonatal hippocampal neurons. While blockade of mGluR1 or mGluR5 alone could interfere with TBS-induced shifts in EGABA in neonates, only a combined blockade could do the same in juveniles. These results indicate that TBS induces a negative shift in EGABA in juvenile hippocampal neurons but a positive shift in neonatal hippocampal neurons via corresponding changes in KCC2 and NKCC1 expressions, respectively. mGluR activation seems to be necessary for both shifts to occur while the specific receptor subtype involved seems to vary.

  14. Regulation of GABA Equilibrium Potential by mGluRs in Rat Hippocampal CA1 Neurons.

    Directory of Open Access Journals (Sweden)

    Bo Yang

    Full Text Available The equilibrium potential for GABA-A receptor mediated currents (EGABA in neonatal central neurons is set at a relatively depolarized level, which is suggested to be caused by a low expression of K+/Cl- co-transporter (KCC2 but a relatively high expression of Na+-K+-Cl- cotransporter (NKCC1. Theta-burst stimulation (TBS in stratum radiatum induces a negative shift in EGABA in juvenile hippocampal CA1 pyramidal neurons. In the current study, the effects of TBS on EGABA in neonatal and juvenile hippocampal CA1 neurons and the underlying mechanisms were examined. Metabotropic glutamate receptors (mGluRs are suggested to modulate KCC2 and NKCC1 levels in cortical neurons. Therefore, the involvement of mGluRs in the regulation of KCC2 or NKCC1 activity, and thus EGABA, following TBS was also investigated. Whole-cell patch recordings were made from Wistar rat hippocampal CA1 pyramidal neurons, in a slice preparation. In neonates, TBS induces a positive shift in EGABA, which was prevented by NKCC1 antisense but not NKCC1 sense mRNA. (RS-a-Methyl-4-carboxyphenylglycine (MCPG, a group I and II mGluR antagonist, blocked TBS-induced shifts in both juvenile and neonatal hippocampal neurons. While blockade of mGluR1 or mGluR5 alone could interfere with TBS-induced shifts in EGABA in neonates, only a combined blockade could do the same in juveniles. These results indicate that TBS induces a negative shift in EGABA in juvenile hippocampal neurons but a positive shift in neonatal hippocampal neurons via corresponding changes in KCC2 and NKCC1 expressions, respectively. mGluR activation seems to be necessary for both shifts to occur while the specific receptor subtype involved seems to vary.

  15. Peptide YY regulates bone remodeling in mice: a link between gut and skeletal biology.

    Directory of Open Access Journals (Sweden)

    Iris P L Wong

    Full Text Available BACKGROUND & AIMS: Gastrointestinal peptides are increasingly being linked to processes controlling the maintenance of bone mass. Peptide YY (PYY, a gut-derived satiety peptide of the neuropeptide Y family, is upregulated in some states that also display low bone mass. Importantly, PYY has high affinity for Y-receptors, particularly Y1R and Y2R, which are known to regulate bone mass. Anorexic conditions and bariatric surgery for obesity influence circulating levels of PYY and have a negative impact on bone mass, but the precise mechanism behind this is unclear. We thus examined whether alterations in PYY expression affect bone mass. METHODS: Bone microstructure and cellular activity were analyzed in germline PYY knockout and conditional adult-onset PYY over-expressing mice at lumbar and femoral sites using histomorphometry and micro-computed tomography. RESULTS: PYY displayed a negative relationship with osteoblast activity. Male and female PYY knockout mice showed enhanced osteoblast activity, with greater cancellous bone mass. Conversely, PYY over-expression lowered osteoblast activity in vivo, via a direct Y1 receptor mediated mechanism involving MAPK stimulation evident in vitro. In contrast to PYY knockout mice, PYY over expression also altered bone resorption, as indicated by greater osteoclast surface, despite the lack of Y-receptor expression in osteoclastic cells. While evident in both sexes, cellular changes were generally more pronounced in females. CONCLUSIONS: These data demonstrate that the gut peptide PYY is critical for the control of bone remodeling. This regulatory axis from the intestine to bone has the potential to contribute to the marked bone loss observed in situations of extreme weight loss and higher circulating PYY levels, such as anorexia and bariatric obesity surgery, and may be important in the maintenance of bone mass in the general population.

  16. The orphan pentameric ligand-gated ion channel pHCl-2 is gated by pH and regulates fluid secretion in Drosophila Malpighian tubules.

    Science.gov (United States)

    Feingold, Daniel; Starc, Tanja; O'Donnell, Michael J; Nilson, Laura; Dent, Joseph A

    2016-09-01

    Pentameric ligand-gated ion channels (pLGICs) constitute a large protein superfamily in metazoa whose role as neurotransmitter receptors mediating rapid, ionotropic synaptic transmission has been extensively studied. Although the vast majority of pLGICs appear to be neurotransmitter receptors, the identification of pLGICs in non-neuronal tissues and homologous pLGIC-like proteins in prokaryotes points to biological functions, possibly ancestral, that are independent of neuronal signalling. Here, we report the molecular and physiological characterization of a highly divergent, orphan pLGIC subunit encoded by the pHCl-2 (CG11340) gene, in Drosophila melanogaster We show that pHCl-2 forms a channel that is insensitive to a wide array of neurotransmitters, but is instead gated by changes in extracellular pH. pHCl-2 is expressed in the Malpighian tubules, which are non-innervated renal-type secretory tissues. We demonstrate that pHCl-2 is localized to the apical membrane of the epithelial principal cells of the tubules and that loss of pHCl-2 reduces urine production during diuresis. Our data implicate pHCl-2 as an important source of chloride conductance required for proper urine production, highlighting a novel role for pLGICs in epithelial tissues regulating fluid secretion and osmotic homeostasis. PMID:27358471

  17. Gamma aminobutyric acid B and 5-hydroxy tryptamine 2A receptors functional regulation during enhanced liver cell proliferation by GABA and 5-HT chitosan nanoparticles treatment.

    Science.gov (United States)

    Shilpa, Joy; Pretty, Mary Abraham; Anitha, Malat; Paulose, Cheramadathikudyil Skaria

    2013-09-01

    Liver is one of the major organs in vertebrates and hepatocytes are damaged by many factors. The liver cell maintenance and multiplication after injury and treatment gained immense interest. The present study investigated the role of Gamma aminobutyric acid (GABA) and serotonin or 5-hydroxytryptamine (5-HT) coupled with chitosan nanoparticles in the functional regulation of Gamma aminobutyric acid B and 5-hydroxy tryptamine 2A receptors mediated cell signaling mechanisms, extend of DNA methylation and superoxide dismutase activity during enhanced liver cell proliferation. Liver injury was achieved by partial hepatectomy of male Wistar rats and the GABA and 5-HT chitosan nanoparticles treatments were given intraperitoneally. The experimental groups were sham operated control (C), partially hepatectomised rats with no treatment (PHNT), partially hepatectomised rats with GABA chitosan nanoparticle (GCNP), 5-HT chitosan nanoparticle (SCNP) and a combination of GABA and 5-HT chitosan nanoparticle (GSCNP) treatments. In GABA and 5-HT chitosan nanoparticle treated group there was a significant decrease (PGABA and 5-HT chitosan nanoparticles induced liver cell proliferation which has therapeutic significance in liver disease management.

  18. The Phospholipid-binding Protein SESTD1 Is a Novel Regulator of the Transient Receptor Potential Channels TRPC4 and TRPC5

    Science.gov (United States)

    Miehe, Susanne; Bieberstein, Andrea; Arnould, Isabelle; Ihdene, Orhia; Rütten, Hartmut; Strübing, Carsten

    2010-01-01

    TRPC4 and TRPC5 are two closely related members of the mammalian transient receptor potential cation channel family that have been implicated in important physiological functions, such as growth cone guidance and smooth muscle contraction. To further unravel the role of TRPC4 and TRPC5 in these processes in vivo, detailed information about the molecular composition of native channel complexes and their association with cellular signaling networks is needed. We therefore searched a human aortic cDNA library for novel TRPC4-interacting proteins using a modified yeast two-hybrid assay. This screen identified SESTD1, a previously uncharacterized protein containing a lipid-binding SEC14-like domain as well as spectrin-type cytoskeleton interaction domains. SESTD1 was found to associate with TRPC4 and TRPC5 via the channel's calmodulin- and inositol 1,4,5-trisphosphate receptor-binding domain. In functional studies, we demonstrate that SESTD1 binds several phospholipid species in vitro and is essential for efficient receptor-mediated activation of TRPC5. Notably, phospholipid binding to SESTD1 was Ca2+-dependent. Because TRPC4 and -5 conduct Ca2+, SESTD1-channel signaling may be bidirectional and also couple TRPC activity to lipid signaling through SESTD1. The modulation of TRPC channel function by specific lipid-binding proteins, such as SESTD1, adds another facet to the complex regulation of these channels complementary to the previously described effects of direct channel-phospholipid interaction. PMID:20164195

  19. The gastric CB1 receptor modulates ghrelin production through the mTOR pathway to regulate food intake.

    Science.gov (United States)

    Senin, Lucia L; Al-Massadi, Omar; Folgueira, Cintia; Castelao, Cecilia; Pardo, Maria; Barja-Fernandez, Silvia; Roca-Rivada, Arturo; Amil, Maria; Crujeiras, Ana B; Garcia-Caballero, Tomas; Gabellieri, Enrico; Leis, Rosaura; Dieguez, Carlos; Pagotto, Uberto; Casanueva, Felipe F; Seoane, Luisa M

    2013-01-01

    Over the years, the knowledge regarding the relevance of the cannabinoid system to the regulation of metabolism has grown steadily. A central interaction between the cannabinoid system and ghrelin has been suggested to regulate food intake. Although the stomach is the main source of ghrelin and CB1 receptor expression in the stomach has been described, little information is available regarding the possible interaction between the gastric cannabinoid and ghrelin systems in the integrated control of energy homeostasis. The main objective of the present work was to assess the functional interaction between these two systems in terms of food intake using a combination of in vivo and in vitro approaches. The present work demonstrates that the peripheral blockade of the CB1 receptor by rimonabant treatment decreased food intake but only in food-deprived animals. This anorexigenic effect is likely a consequence of decreases in gastric ghrelin secretion induced by the activation of the mTOR/S6K1 intracellular pathway in the stomach following treatment with rimonabant. In support of this supposition, animals in which the mTOR/S6K1 intracellular pathway was blocked by chronic rapamycin treatment, rimonabant had no effect on ghrelin secretion. Vagal communication may also be involved because rimonabant treatment was no longer effective when administered to animals that had undergone surgical vagotomy. In conclusion, to the best of our knowledge, the present work is the first to describe a CB1 receptor-mediated mechanism that influences gastric ghrelin secretion and food intake through the mTOR pathway. PMID:24303008

  20. Regulating Rho GTPases and their regulators.

    Science.gov (United States)

    Hodge, Richard G; Ridley, Anne J

    2016-08-01

    Rho GTPases regulate cytoskeletal and cell adhesion dynamics and thereby coordinate a wide range of cellular processes, including cell migration, cell polarity and cell cycle progression. Most Rho GTPases cycle between a GTP-bound active conformation and a GDP-bound inactive conformation to regulate their ability to activate effector proteins and to elicit cellular responses. However, it has become apparent that Rho GTPases are regulated by post-translational modifications and the formation of specific protein complexes, in addition to GTP-GDP cycling. The canonical regulators of Rho GTPases - guanine nucleotide exchange factors, GTPase-activating proteins and guanine nucleotide dissociation inhibitors - are regulated similarly, creating a complex network of interactions to determine the precise spatiotemporal activation of Rho GTPases. PMID:27301673

  1. 表皮生长因子受体通过MAPK/ERK信号通路调节基质金属蛋白酶1表达的研究%Epidermal growth factor receptor mediates matrix metalloproteinase 1 expression in SiHa cells through MAPK/ERK pathways

    Institute of Scientific and Technical Information of China (English)

    张宗峰; 王红丽; 时小丁; 马鑫; 李佩玲

    2015-01-01

    Objective To investigate the regulatory effect of epidermal growth factor receptor (EGFR) on the expression of matrix metalloproteinase 1 (MMP-1) in cervical cancer SiHa cell and to elucidate the related signal transduction mechanisms.Methods SiHa cells were treated with EGF , and the signal transduction pathway blockers of EGFR,PI3-K, MEK, and JNK were used to investigate the effect of EGFR on the expression of MMP-1 and the phosphorylation of signaling pathways.Results EGF induced the expression of MMP-1 at both the mRNA and protein levels (all P <0.05).MMP-1 induction was blocked by MAPK or ERK kinase inhibitors (all P < 0.05).Conclusion Conclusion EGFR up-regulated the synthesis of MMP-1 through the MAPK/ERK pathway.%目的 探讨表皮生长因子受体(EGFR)在宫颈癌SiHa细胞中对基质金属蛋白酶-1(MMP-1)表达的调节作用,明确其相关的信号传导机制.方法 利用表皮生长因子(EGF)作为干预因素,信号通路阻断剂分别阻断EGFR、AKT、ERK、P38和JNK的磷酸化,观察EGFR对MMP-1表达的影响及其下游信号通路的变化.结果 EGF在mRNA和蛋白水平上诱导MMP-1的表达增加(P均<0.05);MAPK和ERK激酶抑制剂在mRNA和蛋白水平上可阻断这种诱导(P均<0.05).结论 EGFR通过MAPK/ERK信号通路上调MMP-1的表达.

  2. Trout Stream Special Regulations

    Data.gov (United States)

    Minnesota Department of Natural Resources — This layer shows Minnesota trout streams that have a special regulation as described in the 2006 Minnesota Fishing Regulations. Road crossings were determined using...

  3. Regulation of Genetic Tests

    Science.gov (United States)

    ... advertised. The Commission has the authority to regulate advertising that delivers health-related information to consumers to ensure that it is not false or misleading. Top of page FDA Regulation and ...

  4. 糖皮质激素诱导的肿瘤坏死因子受体在Tregs介导下的免疫耐受作用的研究进展%Progress on Glucocorticoid-induced TNF Receptor Mediated by Tregs in Immune Tolerance

    Institute of Scientific and Technical Information of China (English)

    谭燕; 王晨虹

    2016-01-01

    糖皮质激素诱导的肿瘤坏死因子受体(glucocorticoid-induced TNF receptor,GITR)是胸腺和外周淋巴器官中调节性T细胞(regulatory T cells,Tregs)表达的一个重要功能分子,在Tregs的分化和扩张中起关键性作用,是人类Tregs非常有效的标记物,在Tregs的免疫调节中发挥重要作用。GITR具有许多重要的生物学活性,包括细胞的增殖、分化、存活和凋亡等,其相互作用可打破Tregs介导的免疫耐受,诱发或加重自身免疫性疾病,如哮喘、糖尿病、关节炎、系统性红斑狼疮等。妊娠选择了免疫耐受这一基本机制,Tregs在保护胎儿免受母体免疫攻击方面发挥重要作用,许多研究已表明:在妊娠期间中断Tregs的相互作用会导致胎儿特异性抗原的产生,继而导致不良妊娠结局。综述GITR在Tregs介导下的免疫耐受作用。%Glucocorticoid-induced tumor necrosis factor receptor (GITR) is an important functional molecular of regulatory T cells (regulatory T cells,Tregs) expressed in thymus and peripheral lymphoid organs. Numerous studies have shown the key role of GITR in differentiation and extension of Tregs. Furdermore,GITR is an effective marker of Tregs and play an important role in immune regulation. GITR has many important biological activities,including cell proliferation,differentiation,survival and apoptosis,etc. The interactions of them can break immune tolerance mediated by Tregs,induce or aggravate autoimmune diseases,such as asthma,diabetes,arthritis and systemic lupus erythematosus,etc. All pregnancies comply with the rules of immune tolerance,Tregs play an important role in protecting fetus from immune attack. Many studies have shown that interruption of the interaction in Tregs during the pregnancy can lead to the generation of fetal specific antigen,which in turn will lead to adverse pregnancy outcome. Now a review will be made here on GITR mediated by Tregs in immune

  5. General Theories of Regulation

    NARCIS (Netherlands)

    Hertog, J.A. den

    1999-01-01

    This chapter makes a distinction between three types of theories of regulation: public interest theories, the Chicago theory of regulation and the public choice theories. The Chicago theory is mainly directed at the explanation of economic regulation; public interest theories and public choice theor

  6. Hepcidin: regulation of the master iron regulator

    OpenAIRE

    2015-01-01

    Iron, an essential nutrient, is required for many diverse biological processes. The absence of a defined pathway to excrete excess iron makes it essential for the body to regulate the amount of iron absorbed; a deficiency could lead to iron deficiency and an excess to iron overload and associated disorders such as anaemia and haemochromatosis respectively. This regulation is mediated by the iron-regulatory hormone hepcidin. Hepcidin binds to the only known iron export protein, ferroportin (FP...

  7. Views of the regulators

    International Nuclear Information System (INIS)

    In dealing with a challenging problem in occupational exposure the nuclear regulator in South Africa concluded that the involvement of stake holders was critical. Valuable lessons were learnt in the process. These related to co-operation amongst regulators, the involvement of regulators in addressing occupational exposure problems, the training of workers by the regulator and the need for technical training of the workers. In general, it was also learnt that regulators should establish mechanisms to measure and continuously improve the satisfaction of their stake holders. (author)

  8. Differential regulation of acid sphingomyelinase in macrophages stimulated with oxidized low-density lipoprotein (LDL) and oxidized LDL immune complexes: role in phagocytosis and cytokine release.

    Science.gov (United States)

    Truman, Jean-Philip; Al Gadban, Mohammed M; Smith, Kent J; Jenkins, Russell W; Mayroo, Nalini; Virella, Gabriel; Lopes-Virella, Maria F; Bielawska, Alicja; Hannun, Yusuf A; Hammad, Samar M

    2012-05-01

    Oxidized low-density lipoprotein (oxLDL) and oxLDL-containing immune complexes (oxLDL-IC) contribute to the formation of lipid-laden macrophages (foam cells). Fcγ receptors mediate uptake of oxLDL-IC, whereas scavenger receptors internalize oxLDL. We have previously reported that oxLDL-IC, but not free oxLDL, activate macrophages and prolong their survival. Sphingomyelin is a major constituent of cell membranes and lipoprotein particles and acid sphingomyelinase (ASMase) hydrolyses sphingomyelin to generate the bioactive lipid ceramide. ASMase exists in two forms: lysosomal (L-ASMase) and secretory (S-ASMase). In this study we examined whether oxLDL and oxLDL-IC regulate ASMase differently, and whether ASMase mediates monocyte/macrophage activation and cytokine release. The oxLDL-IC, but not oxLDL, induced early and consistent release of catalytically active S-ASMase. The oxLDL-IC also consistently stimulated L-ASMase activity, whereas oxLDL induced a rapid transient increase in L-ASMase activity before it steadily declined below baseline. Prolonged exposure to oxLDL increased L-ASMase activity; however, activity remained significantly lower than that induced by oxLDL-IC. Further studies were aimed at defining the function of the activated ASMase. In response to oxLDL-IC, heat-shock protein 70B' (HSP70B') was up-regulated and localized with redistributed ASMase in the endosomal compartment outside the lysosome. Treatment with oxLDL-IC induced the formation and release of HSP70-containing and IL-1β-containing exosomes via an ASMase-dependent mechanism. Taken together, the results suggest that oxLDL and oxLDL-IC differentially regulate ASMase activity, and the pro-inflammatory responses to oxLDL-IC are mediated by prolonged activation of ASMase. These findings may contribute to increased understanding of mechanisms mediating macrophage involvement in atherosclerosis.

  9. Nuclear safety regulations

    International Nuclear Information System (INIS)

    The Nuclear Safety Regulations for Nuclear Installations and Nuclear Safety Codes for Nuclear Pressure Retaining Components were issued by the NNSA in 1995. The Atomic Act and Regulations on the Safety Regulation for Transportation of Radioactive Materials have been finished and submitted to the State Council in 1995. At the same time the NNSA organized a revised collection of regulations on nuclear safety in both Chinese and English, titled 'The Collection of Regulations on Nuclear Safety of the People's Republic of China'. To enhance the implementation of newly issued nuclear safety regulations, the NNSA conducted seven times of propagating activities in relation to the regulations for nuclear pressure retaining components and research reactors design and operating in 1995

  10. A spatial focusing model for G protein signals. Regulator of G protein signaling (RGS) protien-mediated kinetic scaffolding.

    Science.gov (United States)

    Zhong, Huailing; Wade, Susan M; Woolf, Peter J; Linderman, Jennifer J; Traynor, John R; Neubig, Richard R

    2003-02-28

    Regulators of G protein signaling (RGS) are GTPase-accelerating proteins (GAPs), which can inhibit heterotrimeric G protein pathways. In this study, we provide experimental and theoretical evidence that high concentrations of receptors (as at a synapse) can lead to saturation of GDP-GTP exchange making GTP hydrolysis rate-limiting. This results in local depletion of inactive heterotrimeric G-GDP, which is reversed by RGS GAP activity. Thus, RGS enhances receptor-mediated G protein activation even as it deactivates the G protein. Evidence supporting this model includes a GTP-dependent enhancement of guanosine 5'-3-O-(thio)triphosphate (GTPgammaS) binding to G(i) by RGS. The RGS domain of RGS4 is sufficient for this, not requiring the NH(2)- or COOH-terminal extensions. Furthermore, a kinetic model including only the GAP activity of RGS replicates the GTP-dependent enhancement of GTPgammaS binding observed experimentally. Finally in a Monte Carlo model, this mechanism results in a dramatic "spatial focusing" of active G protein. Near the receptor, G protein activity is maintained even with RGS due to the ability of RGS to reduce depletion of local Galpha-GDP levels permitting rapid recoupling to receptor and maintained G protein activation near the receptor. In contrast, distant signals are suppressed by the RGS, since Galpha-GDP is not depleted there. Thus, a novel RGS-mediated "kinetic scaffolding" mechanism is proposed which narrows the spatial range of active G protein around a cluster of receptors limiting the spill-over of G protein signals to more distant effector molecules, thus enhancing the specificity of G(i) protein signals.

  11. Target-specific regulation of presynaptic release properties at auditory nerve terminals in the avian cochlear nucleus.

    Science.gov (United States)

    Ahn, J; MacLeod, K M

    2016-03-01

    Short-term synaptic plasticity (STP) acts as a time- and firing rate-dependent filter that mediates the transmission of information across synapses. In the auditory brain stem, the divergent pathways that encode acoustic timing and intensity information express differential STP. To investigate what factors determine the plasticity expressed at different terminals, we tested whether presynaptic release probability differed in the auditory nerve projections to the two divisions of the avian cochlear nucleus, nucleus angularis (NA) and nucleus magnocellularis (NM). Estimates of release probability were made with an open-channel blocker ofN-methyl-d-aspartate (NMDA) receptors. Activity-dependent blockade of NMDA receptor-mediated excitatory postsynaptic currents (EPSCs) with application of 20 μM (+)-MK801 maleate was more rapid in NM than in NA, indicating that release probability was significantly higher at terminals in NM. Paired-pulse ratio (PPR) was tightly correlated with the blockade rate at terminals in NA, suggesting that PPR was a reasonable proxy for relative release probability at these synapses. To test whether release probability was similar across convergent inputs onto NA neurons, PPRs of different nerve inputs onto the same postsynaptic NA target neuron were measured. The PPRs, as well as the plasticity during short trains, were tightly correlated across multiple inputs, further suggesting that release probability is coordinated at auditory nerve terminals in a target-specific manner. This highly specific regulation of STP in the auditory brain stem provides evidence that the synaptic dynamics are tuned to differentially transmit the auditory information in nerve activity into parallel ascending pathways. PMID:26719087

  12. Reinforcement-related regulation of AMPA glutamate receptor subunits in the ventral tegmental area enhances motivation for cocaine.

    Science.gov (United States)

    Choi, Kwang Ho; Edwards, Scott; Graham, Danielle L; Larson, Erin B; Whisler, Kimberly N; Simmons, Diana; Friedman, Allyson K; Walsh, Jessica J; Rahman, Zia; Monteggia, Lisa M; Eisch, Amelia J; Neve, Rachael L; Nestler, Eric J; Han, Ming-Hu; Self, David W

    2011-05-25

    Chronic cocaine use produces numerous biological changes in brain, but relatively few are functionally associated with cocaine reinforcement. Here we show that daily intravenous cocaine self-administration, but not passive cocaine administration, induces dynamic upregulation of the AMPA glutamate receptor subunits GluR1 and GluR2 in the ventral tegmental area (VTA) of rats. Increases in GluR1 protein and GluR1(S845) phosphorylation are associated with increased GluR1 mRNA in self-administering animals, whereas increased GluR2 protein levels occurred despite substantial decreases in GluR2 mRNA. We investigated the functional significance of GluR1 upregulation in the VTA on cocaine self-administration using localized viral-mediated gene transfer. Overexpression of GluR1(WT) in rat VTA primarily infected dopamine neurons (75%) and increased AMPA receptor-mediated membrane rectification in these neurons with AMPA application. Similar GluR1(WT) overexpression potentiated locomotor responses to intra-VTA AMPA, but not NMDA, infusions. In cocaine self-administering animals, overexpression of GluR1(WT) in the VTA markedly increased the motivation for cocaine injections on a progressive ratio schedule of cocaine reinforcement. In contrast, overexpression of protein kinase A-resistant GluR1(S845A) in the VTA reduced peak rates of cocaine self-administration on a fixed ratio reinforcement schedule. Neither viral vector altered sucrose self-administration, and overexpression of GluR1(WT) or GluR1(S845A) in the adjacent substantia nigra had no effect on cocaine self-administration. Together, these results suggest that dynamic regulation of AMPA receptors in the VTA during cocaine self-administration contributes to cocaine addiction by acting to facilitate subsequent cocaine use.

  13. The development of regulations

    International Nuclear Information System (INIS)

    In October 2002, The Act on Protection Against Ionising Radiation and Nuclear Safety which regulates all aspects of protection against ionising radiation and nuclear safety entered into force in Slovenia. The Slovenian government and its responsible ministries shall issue several governmental and ministerial regulations to support the above - mentioned act. The Slovenian Nuclear Safety Administration (SNSA) which acts within the Ministry of the Environment, Spatial Planing and Energy takes an active part in drafting the regulations which are defined in the act. Due to a very comprehensive and pretentious task, that is to be completed in a relatively short period of time, taking into consideration the involvement of stakeholders and all competent ministries, the SNSA within the Quality Management System developed a special procedure that insures the systematic approach to the preparation of regulations. The article will briefly represent the process that: defines the preparation, development, harmonisation, review, approval and issue of regulations and uniforms the format of developed regulations. (author)

  14. TOWARD MORE EFFECTIVE REGULATION

    Energy Technology Data Exchange (ETDEWEB)

    J. GRAF

    2000-06-01

    This paper proposes a model relationship between the operator engaged in a hazardous activity, the regulator of that activity, and the general public. The roles and responsibilities of each entity are described in a way that allows effective communication flow. The role of the regulator is developed using the steam boiler as an example of a hazard subject to regulation; however, the model applies to any regulated activity. In this model the safety analyst has the extremely important role of communicating sometimes difficult technical information to the regulator in a way that the regulator can provide credible assurance to the general public as to the adequacy of the control of the hazardous activity. The conclusion asserts that acceptance of the model, understanding of the roles and responsibilities and definition of who communicates what information to whom will mitigate frustration on the part of each of the three entities.

  15. Nuclear safety regulations

    International Nuclear Information System (INIS)

    The enactment of nuclear safety regulations in 1996 is mainly focused on the preparation of related regulations, and safety guides for nuclear materials control, the reprocessing installations of spent fuels, the treatment and disposal for radioactive waste. The NNSA also assists the departments concerned of the State Council for modification on the 'Atomic Energy Act' (draft) and the' Regulations on the Safety Supervision and Control of Radioactive Materials Transportation' (draft)

  16. Emotional regulation and friendship

    OpenAIRE

    Zaccagnini, J.L.; Ruiz-Aranda, D.

    2013-01-01

    Previous literature has been shown that emotional regulation facilitates the establishment and maintenance of social relations (Dodge Garber, 1991; Saarni, 1999). The objective of the present study was to analyze the influence of emotional regulation (Gross y John, 2003) in positive friendship (Berscheid, 2003), specifically at the level of intimacy with friends. In addition, we examined the mediating role of positive emotions in the relationship between the emotional regulation and the leve...

  17. Accounting Regulation in Ukraine

    OpenAIRE

    Hora, Michal; Chyzevska, Ludmila

    2013-01-01

    The aim of the paper is to evaluate the regulation and organization of accounting in Ukraine under the changes in the national economic system development and impact of IFRS implementation. The system of legal regulation of accounting in Ukraine is presented by five levels, each comprised of a number of corresponding subjects of regulation and documents. Typical Chart of Accounts is evidence of the continental accounting model in Ukraine. The accounting standards provide freedom of choice as ...

  18. Dynamic Regulation of Cell Volume and Extracellular ATP of Human Erythrocytes

    Science.gov (United States)

    Leal Denis, M. Florencia; Alvarez, H. Ariel; Lauri, Natalia; Alvarez, Cora L.; Chara, Osvaldo; Schwarzbaum, Pablo J.

    2016-01-01

    Introduction The peptide mastoparan 7 (MST7) triggered in human erythrocytes (rbcs) the release of ATP and swelling. Since swelling is a well-known inducer of ATP release, and extracellular (ATPe), interacting with P (purinergic) receptors, can affect cell volume (Vr), we explored the dynamic regulation between Vr and ATPe. Methods and Treatments We made a quantitative assessment of MST7-dependent kinetics of Vr and of [ATPe], both in the absence and presence of blockers of ATP efflux, swelling and P receptors. Results In rbcs 10 μM MST7 promoted acute, strongly correlated changes in [ATPe] and Vr. Whereas MST7 induced increases of 10% in Vr and 190 nM in [ATPe], blocking swelling in a hyperosmotic medium + MST7 reduced [ATPe] by 40%. Pre-incubation of rbcs with 10 μM of either carbenoxolone or probenecid, two inhibitors of the ATP conduit pannexin 1, reduced [ATPe] by 40–50% and swelling by 40–60%, while in the presence of 80 U/mL apyrase, an ATPe scavenger, cell swelling was prevented. While exposure to 10 μM NF110, a blocker of ATP-P2X receptors mediating sodium influx, reduced [ATPe] by 48%, and swelling by 80%, incubation of cells in sodium free medium reduced swelling by 92%. Analysis and Discussion Results were analyzed by means of a mathematical model where ATPe kinetics and Vr kinetics were mutually regulated. Model dependent fit to experimental data showed that, upon MST7 exposure, ATP efflux required a fast 1960-fold increase of ATP permeability, mediated by two kinetically different conduits, both of which were activated by swelling and inactivated by time. Both experimental and theoretical results suggest that, following MST7 exposure, ATP is released via two conduits, one of which is mediated by pannexin 1. The accumulated ATPe activates P2X receptors, followed by sodium influx, resulting in cell swelling, which in turn further activates ATP release. Thus swelling and P2X receptors constitute essential components of a positive feedback loop

  19. β-Receptor-mediated increase in cerebral blood flow during hypoglycemia

    International Nuclear Information System (INIS)

    The authors tested the hypothesis that β-adrenergic receptor stimulation is involved with the increase in regional cerebral blood flow (rCBF) during hypoglycemia. Rats were surgically prepared with the use of halothane-nitrous oxide anesthesia. A plaster restraining cast was placed around the hindquarters, and anesthesia was discontinued. Hypoglycemia was produced by an intravenous injection of insulin; normoglycemic control rates were given saline. Propranolol was administered to some control and some hypoglycemic rats to block the β-adrenergic receptors. Regional CBF was measured using 4-[N-methyl-14C]iodoantipyrine. Regional CBF increased during hypoglycemia in rats that were not treated with propranolol. The increase varied from ∼60 to 200% depending on the brain region. During hypoglycemia, propranolol abolished the increase in rCBF in the hypothalamus, cerebellum, and pyramidal tract. In other regions the increase in rCBF was only 33-65% of the increase in hypoglycemic rats that were not treated with propranolol. They conclude that β-receptor stimulation plays a major role in the increase in rCBF during hypoglycemia

  20. beta. -Receptor-mediated increase in cerebral blood flow during hypoglycemia

    Energy Technology Data Exchange (ETDEWEB)

    Hollinger, B.R.; Bryan, R.M. (Pennsylvania State Univ., Hershey (USA))

    1987-10-01

    The authors tested the hypothesis that {beta}-adrenergic receptor stimulation is involved with the increase in regional cerebral blood flow (rCBF) during hypoglycemia. Rats were surgically prepared with the use of halothane-nitrous oxide anesthesia. A plaster restraining cast was placed around the hindquarters, and anesthesia was discontinued. Hypoglycemia was produced by an intravenous injection of insulin; normoglycemic control rates were given saline. Propranolol was administered to some control and some hypoglycemic rats to block the {beta}-adrenergic receptors. Regional CBF was measured using 4-(N-methyl-{sup 14}C)iodoantipyrine. Regional CBF increased during hypoglycemia in rats that were not treated with propranolol. The increase varied from {approximately}60 to 200% depending on the brain region. During hypoglycemia, propranolol abolished the increase in rCBF in the hypothalamus, cerebellum, and pyramidal tract. In other regions the increase in rCBF was only 33-65% of the increase in hypoglycemic rats that were not treated with propranolol. They conclude that {beta}-receptor stimulation plays a major role in the increase in rCBF during hypoglycemia.

  1. Receptor-mediated sorting of soluble vacuolar proteins: myths, facts, and a new model.

    Science.gov (United States)

    Robinson, David G; Neuhaus, Jean-Marc

    2016-08-01

    To prevent their being released to the cell exterior, acid hydrolases are recognized by receptors at some point in the secretory pathway and diverted towards the lytic compartment of the cell (lysosome or vacuole). In animal cells, the receptor is called the mannosyl 6-phosphate receptor (MPR) and it binds hydrolase ligands in the trans-Golgi network (TGN). These ligands are then sequestered into clathrin-coated vesicles (CCVs) because of motifs in the cytosolic tail of the MPR which interact first with monomeric adaptors (Golgi-localized, Gamma-ear-containing, ARF-binding proteins, GGAs) and then with tetrameric (adaptin) adaptor complexes. The CCVs then fuse with an early endosome, whose more acidic lumen causes the ligands to dissociate. The MPRs are then recycled back to the TGN via retromer-coated carriers. Plants have vacuolar sorting receptors (VSRs) which were originally identified in CCVs isolated from pea (Pisum sativum L.) cotyledons. It was therefore assumed that VSRs would have an analogous function in plants to MPRs in animals. Although this dogma has enjoyed wide support over the last 20 years there are many inconsistencies. Recently, results have been published which are quite contrary to it. It now emerges that VSRs and their ligands can interact very early in the secretory pathway, and dissociate in the TGN, which, in contrast to its mammalian counterpart, has a pH of 5.5. Multivesicular endosomes in plants lack proton pump complexes and consequently have an almost neutral internal pH, which discounts them as organelles of pH-dependent receptor-ligand dissociation. These data force a critical re-evaluation of the role of CCVs at the TGN, especially considering that vacuolar cargo ligands have never been identified in them. We propose that one population of TGN-derived CCVs participate in retrograde transport of VSRs from the TGN. We also present a new model to explain how secretory and vacuolar cargo proteins are effectively separated after entering the late Golgi/TGN compartments.

  2. Receptor-Mediated and Lectin-Like Activities of Carp (Cyprinus carpio) TNF-¿

    NARCIS (Netherlands)

    Forlenza, M.; Magez, S.; Scharsack, J.P.; Westphal, A.H.; Savelkoul, H.F.J.; Wiegertjes, G.F.

    2009-01-01

    Functional characterization of TNF- in species other than mammalian vertebrates is limited, and TNF- has been studied in a limited number of fish species, primarily in vitro using recombinant proteins. Studies on TNF- from different fish species so far pointed to several inconsistencies, in particul

  3. Receptor-mediated sorting of soluble vacuolar proteins: myths, facts, and a new model.

    Science.gov (United States)

    Robinson, David G; Neuhaus, Jean-Marc

    2016-08-01

    To prevent their being released to the cell exterior, acid hydrolases are recognized by receptors at some point in the secretory pathway and diverted towards the lytic compartment of the cell (lysosome or vacuole). In animal cells, the receptor is called the mannosyl 6-phosphate receptor (MPR) and it binds hydrolase ligands in the trans-Golgi network (TGN). These ligands are then sequestered into clathrin-coated vesicles (CCVs) because of motifs in the cytosolic tail of the MPR which interact first with monomeric adaptors (Golgi-localized, Gamma-ear-containing, ARF-binding proteins, GGAs) and then with tetrameric (adaptin) adaptor complexes. The CCVs then fuse with an early endosome, whose more acidic lumen causes the ligands to dissociate. The MPRs are then recycled back to the TGN via retromer-coated carriers. Plants have vacuolar sorting receptors (VSRs) which were originally identified in CCVs isolated from pea (Pisum sativum L.) cotyledons. It was therefore assumed that VSRs would have an analogous function in plants to MPRs in animals. Although this dogma has enjoyed wide support over the last 20 years there are many inconsistencies. Recently, results have been published which are quite contrary to it. It now emerges that VSRs and their ligands can interact very early in the secretory pathway, and dissociate in the TGN, which, in contrast to its mammalian counterpart, has a pH of 5.5. Multivesicular endosomes in plants lack proton pump complexes and consequently have an almost neutral internal pH, which discounts them as organelles of pH-dependent receptor-ligand dissociation. These data force a critical re-evaluation of the role of CCVs at the TGN, especially considering that vacuolar cargo ligands have never been identified in them. We propose that one population of TGN-derived CCVs participate in retrograde transport of VSRs from the TGN. We also present a new model to explain how secretory and vacuolar cargo proteins are effectively separated after entering the late Golgi/TGN compartments. PMID:27262127

  4. Interaction between thyrotropin-releasing hormone (TRH) and NMDA-receptor-mediated responses in hypoglossal motoneurones

    DEFF Research Database (Denmark)

    Rekling, J C

    1992-01-01

    The effect of thyrotropin-releasing hormone (TRH) on the responses to excitatory amino acids was investigated in hypoglossal motoneurones in an in vitro preparation of the brainstem from guinea pigs using current clamp and discontinuous single electrode voltage clamp (dSEVC). Bath application of 20......-50 microM TRH markedly potentiated the response to iontophoretically applied NMDA, whereas no potentiation of the response to glutamate, aspartate or quisqualic acid was seen. Voltage clamp experiments showed that TRH did not increase the current flowing through NMDA channels, thus a direct modulatory role...... of TRH on NMDA channels was not a likely explanation of the potentiation. Voltage clamp studies of the current-voltage relationship showed that the potentiation of the response to NMDA and lack of potentiation of the response to quisqualic acid was a result of an interaction between the actions of TRH...

  5. Asialoglycoprotein Receptor-Mediated Gene Delivery to Hepatocytes Using Galactosylated Polymers.

    Science.gov (United States)

    Thapa, Bindu; Kumar, Piyush; Zeng, Hongbo; Narain, Ravin

    2015-09-14

    Highly efficient, specific, and nontoxic gene delivery vector is required for gene therapy to the liver. Hepatocytes exclusively express asialoglycoprotein receptor (ASGPR), which can recognize and bind to galactose or N-acetylgalactosamine. Galactosylated polymers are therefore explored for targeted gene delivery to the liver. A library of safe and stable galactose-based glycopolymers that can specifically deliver genes to hepatocytes were synthesized having different architectures, compositions, and molecular weights via the reversible addition-fragmentation chain transfer process. The physical and chemical properties of these polymers have a great impact on gene delivery efficacy into hepatocytes, as such block copolymers are found to form more stable complexes with plasmid and have high gene delivery efficiency into ASGPR expressing hepatocytes. Transfection efficiency and uptake of polyplexes with these polymers decreased significantly by preincubation of hepatocytes with free asialofetuin or by adding free asialofetuin together with polyplexes into hepatocytes. The results confirmed that polyplexes with these polymers were taken up specifically by hepatocytes via ASGPR-mediated endocytosis. The results from transfection efficiency and uptake of these polymers in cells without ASGPR, such as SK Hep1 and HeLa cells, further support this mechanism. Since in vitro cytotoxicity assays prove these glycopolymers to be nontoxic, they may be useful for delivery of clinically important genes specifically to the liver.

  6. BURN-INDUCED ALTERATIONS IN TOLL-LIKE RECEPTOR-MEDIATED RESPONSES BY BRONCHOALVEOLAR LAVAGE CELLS

    OpenAIRE

    Richard F. Oppeltz; Rani, Meenakshi; Zhang, Qiong; Schwacha, Martin G.

    2011-01-01

    Burn is associated with profound inflammation and activation of the innate immune system in multiple organ beds, including the lung. Similarly, toll-like receptors (TLR) are associated with innate immune activation. Nonetheless, it is unclear what impact burn has on TLR-induced inflammatory responses in the lung.

  7. Application of an in silico liver model to determine nuclear receptor mediated pathways in liver cancer

    Science.gov (United States)

    Nuclear receptors (NRs) are ligand-activated transcription factors that control diverse cellular processes. Chronic stimulation of some NRs in rodents can result in increased incidence of liver tumors. These are generally thought to develop through a non-genotoxic mechanism with...

  8. Loss of receptor-mediated 86Rb efflux from pig aortic endothelial cells in culture.

    OpenAIRE

    Ager, A.; Martin, W

    1983-01-01

    The responsiveness of freshly-isolated and subcultured pig aortic endothelial cells to adenosine triphosphate (ATP), bradykinin and ionophore A23187 was compared by monitoring agonist-induced 86Rb efflux. ATP, bradykinin and ionophore A23187 stimulated 86Rb efflux from freshly-isolated cells. ATP and bradykinin, which act via specific receptors, were less effective at inducing 86Rb efflux from subcultured cells but ionophore A23187 was as effective on subcultured as on freshly-isolated cells....

  9. Chlorotoxin Fused to IgG-Fc Inhibits Glioblastoma Cell Motility via Receptor-Mediated Endocytosis

    Directory of Open Access Journals (Sweden)

    Tomonari Kasai

    2012-01-01

    Full Text Available Chlorotoxin is a 36-amino acid peptide derived from Leiurus quinquestriatus (scorpion venom, which has been shown to inhibit low-conductance chloride channels in colonic epithelial cells. Chlorotoxin also binds to matrix metalloproteinase-2 and other proteins on glioma cell surfaces. Glioma cells are considered to require the activation of matrix metalloproteinase-2 during invasion and migration. In this study, for targeting glioma, we designed two types of recombinant chlorotoxin fused to human IgG-Fcs with/without a hinge region. Chlorotoxin fused to IgG-Fcs was designed as a dimer of 60 kDa with a hinge region and a monomer of 30 kDa without a hinge region. The monomeric and dimeric forms of chlorotoxin inhibited cell proliferation at 300 nM and induced internalization in human glioma A172 cells. The monomer had a greater inhibitory effect than the dimer; therefore, monomeric chlorotoxin fused to IgG-Fc was multivalently displayed on the surface of bionanocapsules to develop a drug delivery system that targeted matrix metalloproteinase-2. The target-dependent internalization of bionanocapsules in A172 cells was observed when chlorotoxin was displayed on the bionanocapsules. This study indicates that chlorotoxin fused to IgG-Fcs could be useful for the active targeting of glioblastoma cells.

  10. Basolateral amygdala CB1 cannabinoid receptors mediate nicotine-induced place preference.

    Science.gov (United States)

    Hashemizadeh, Shiva; Sardari, Maryam; Rezayof, Ameneh

    2014-06-01

    In the present study, the effects of bilateral microinjections of cannabinoid CB1 receptor agonist and antagonist into the basolateral amygdala (intra-BLA) on nicotine-induced place preference were examined in rats. A conditioned place preference (CPP) apparatus was used for the assessment of rewarding effects of the drugs in adult male Wistar rats. Subcutaneous (s.c.) administration of nicotine (0.2mg/kg) induced a significant CPP, without any effect on the locomotor activity during the testing phase. Intra-BLA microinjection of a non-selective cannabinoid CB1/CB2 receptor agonist, WIN 55,212-2 (0.1-0.5 μg/rat) with an ineffective dose of nicotine (0.1mg/kg, s.c.) induced a significant place preference. On the other hand, intra-BLA administration of AM251 (20-60 ng/rat), a selective cannabinoid CB1 receptor antagonist inhibited the acquisition of nicotine-induced place preference. It should be considered that the microinjection of the same doses of WIN 55,212-2 or AM251 into the BLA, by itself had no effect on the CPP score. The administration of a higher dose of AM251 (60 ng/rat) during the acquisition decreased the locomotor activity of animals on the testing phase. Interestingly, the microinjection of AM251 (20 and 40 ng/rat), but not WIN55,212-2 (0.1-0.5 μg/rat), into the BLA inhibited the expression of nicotine-induced place preference without any effect on the locomotor activity. Taken together, these findings support the possible role of endogenous cannabinoid system of the BLA in the acquisition and the expression of nicotine-induced place preference. Furthermore, it seems that there is a functional interaction between the BLA cannabinoid receptors and nicotine in producing the rewarding effects.

  11. How toxic is oil? Investigating specific receptor-mediated toxic effects of crude and refined oils

    NARCIS (Netherlands)

    Vrabie, C.M.

    2011-01-01

    Crude oils and refined oil products are major pollutants of the environment. Large oil spills, such as the recent blowout of the Deepwater Horizon in the Gulf of Mexico, raise concerns about the long term health effects of petroleum hydrocarbon exposure on wildlife and humans. In the environmental r

  12. Direct and indirect endocrine disruption : aromatase and estrogen receptor-mediated processes in breast cancer development

    NARCIS (Netherlands)

    Heneweer, Marjoke

    2005-01-01

    Endocrine disrupting chemicals (EDCs) have been defined by the World Health Organization as: “exogenous substances or mixtures that alters function(s) of the endocrine system and causes adverse health effects in an intact organism, or its progeny, or (sub)populations”. Synthetic, as well as, natura

  13. Formulating tumor-homing peptides as regular nanoparticles enhances receptor-mediated cell penetrability

    OpenAIRE

    Xu, Zhikun; Unzueta Elorza, Ugutz; Roldán, Mónica; Mangues, Ramón; Sánchez Chardi, Alejandro; Ferrer Miralles, Neus; Villaverde Corrales, Antonio; Vázquez Gómez, Esther

    2015-01-01

    The authors acknowledge the financial support granted to E.V. (PI12/00327) and R.M. (PI12/01861) from FIS, to E.V. (TV32013-133930) and to R.M. and A.V. (TV32013-132031) from La Marató de TV3 (416/C/2013), to A.V. from MINECO (Grant BIO2013-41019-P) and from the Centro de Investigación Biomédica en Red (CIBER) de Bioingeniería, Biomateriales y Nanomedicina (NANOPROTHER and NANOCOMETS projects). We are grateful to the Protein Production Platform (CIBER-BBN-UAB) for protein production and purif...

  14. Modulation of Toll-like receptor-mediated activation of Microglia

    NARCIS (Netherlands)

    Putten, C. M.-T. van der

    2015-01-01

    Microglia are the resident macrophages of the central nervous system (CNS). Like other tissue macrophages, microglia have many different functions under physiological as well as pathological conditions. Microglia can contribute to the initiation, progression and resolution of disease processes and m

  15. Melanocortin receptor-mediated effects on obesity are distributed over specific hypothalamic regions

    NARCIS (Netherlands)

    M.W.A. de Backer; S.E. la Fleur; M.A.D. Brans; A.J. van Rozen; M.C.M. Luijendijk; M. Merkestein; K.M. Garner; E.M. van der Zwaal; R.A.H. Adan

    2011-01-01

    Objective:Reduction of melanocortin signaling in the brain results in obesity. However, where in the brain reduced melanocortin signaling mediates this effect is poorly understood.Design:We determined the effects of long-term inhibition of melanocortin receptor activity in specific brain regions of

  16. beta. -adrenergic receptor-mediated hepatic glycogenolysis is increased in aged male rats

    Energy Technology Data Exchange (ETDEWEB)

    Herring, P.A.; Graham, S.M.; Arinze, I.J.

    1986-03-05

    The effect of age on catecholamine-stimulated glycogenolysis was studied in isolated hepatocytes prepared from 3, 12, and 24 month-old rats. Glucose release was stimulated by epinephrine and norepinephrine, this was inhibited by phentolamine and prazosin. Isoproterenol (ISO) stimulated glycogenolysis only in cells from 24 month-old rats, this was blocked by propranolol. In liver plasma membranes, binding of (/sup 3/H)yohimbine (100-130 fmol/mg protein) did not change with age, whereas (/sup 3/H)prazosin binding decreased from 870 fmol/mg at 3 months to 435 fmol/mg at 12 months, but subsequently rose to 656 fmol/mg at 24 months. (/sup 125/I)Cyanopindolol binding increased from 8 fmol/mg at 3 months to 19 fmol/mg at 24 months. The proportion of ..beta..-receptors in the high affinity state increased from 28% at 3 months to 42% at 24 months. ISO stimulated adenylate cyclase at 24 months but not at 3 months. Basal, fluoride-, GTP-, and Gpp(NH)p-stimulated activities were 1.4- to 2.4-fold greater at 24 months than at 3 months. These results suggest an age-related increase in the sensitivity of adenylate cyclase to ..beta..-receptor stimulation.

  17. Identification of Novel Pathways That Control Farnesoid X Receptor-mediated Hypocholesterolemia*

    OpenAIRE

    Zhang, Yanqiao; Yin, Liya; Anderson, Jody; Ma, Huiyan; Gonzalez, Frank J.; Willson, Timothy M.; Edwards, Peter A.

    2009-01-01

    Farnesoid X receptor (FXR) plays important regulatory roles in bile acid, lipoprotein, and glucose homeostasis. Here, we have utilized Fxr−/− mice and mice deficient in scavenger receptor class B type I (SR-BI), together with an FXR-specific agonist and adenovirus expressing hepatocyte nuclear factor 4α or constitutively active FXR, to identify the mechanisms by which activation of FXR results in hypocholesterolemia. We identify a novel pathway linking FXR to changes in hepatic p-JNK, hepatoc...

  18. Modeling Nuclear Receptor-Mediated Activity and Hepatotoxicity with Boolean Networks

    Science.gov (United States)

    Predicting the human health risk of chronic exposure to environmental contaminants remains an open problem. Chronic exposure to a wide array of chemicals – e.g., conazoles, perfluourinated chemicals and phthalates – has been associated with a range of hepatic lesions in rodents t...

  19. IL-1 Receptors Mediate Persistent, but Not Acute, Airway Hyperreactivity to Ozone in Guinea Pigs

    OpenAIRE

    Verhein, Kirsten C.; Jacoby, David B.; Allison D Fryer

    2008-01-01

    Ozone exposure in the lab and environment causes airway hyperreactivity lasting at least 3 days in humans and animals. In guinea pigs 1 day after ozone exposure, airway hyperreactivity is mediated by eosinophils that block neuronal M2 muscarinic receptor function, thus increasing acetylcholine release from airway parasympathetic nerves. However, mechanisms of ozone-induced airway hyperreactivity change over time, so that depleting eosinophils 3 days after ozone makes airway hyperreactivity wo...

  20. Techniques to Study Specific Cell-Surface Receptor-Mediated Cellular Vitamin A Uptake

    OpenAIRE

    KAWAGUCHI, RIKI; Sun, Hui

    2010-01-01

    STRA6 is a multitransmembrane domain protein that was recently identified as the cell-surface receptor for plasma retinol binding protein (RBP), the vitamin A carrier protein in the blood. STRA6 binds to RBP with high affinity and mediates cellular uptake of vitamin A from RBP. It is not homologous to any known receptors, transporters, and channels, and it represents a new class of membrane transport protein. Consistent with the diverse physiological functions of vitamin A, STRA6 is widely ex...

  1. Astrocytic β2-adrenergic receptors mediate hippocampal long-term memory consolidation

    KAUST Repository

    Gao, Virginia

    2016-07-12

    Emotionally relevant experiences form strong and long-lasting memories by critically engaging the stress hormone/neurotransmitter noradrenaline, which mediates and modulates the consolidation of these memories. Noradrenaline acts through adrenergic receptors (ARs), of which β2- Adrenergic receptors (βARs) are of particular importance. The differential anatomical and cellular distribution of βAR subtypes in the brain suggests that they play distinct roles in memory processing, although much about their specific contributions and mechanisms of action remains to be understood. Here we show that astrocytic rather than neuronal β2ARs in the hippocampus play a key role in the consolidation of a fear-based contextual memory. These hippocampal β2ARs, but not β1ARs, are coupled to the training-dependent release of lactate from astrocytes, which is necessary for long- Term memory formation and for underlying molecular changes. This key metabolic role of astrocytic β2ARs may represent a novel target mechanism for stress-related psychopathologies and neurodegeneration.

  2. Acid-responsive PEGylated doxorubicin prodrug nanoparticles for neuropilin-1 receptor-mediated targeted drug delivery.

    Science.gov (United States)

    Song, Huijuan; Zhang, Ju; Wang, Weiwei; Huang, Pingsheng; Zhang, Yumin; Liu, Jianfeng; Li, Chen; Kong, Deling

    2015-12-01

    Self-assembled prodrug nanoparticles have demonstrated great promise in cancer chemotherapy. In the present study, we developed a new kind of prodrug nanoparticles for targeted drug delivery. PEGylated doxorubicin conjugate with an acid-cleavable cis-aconityl spacer was prepared. Then it was functionalized with a tumor-penetrating peptide, Cys-Arg-Gly-Asp-Lys (CRGDK), providing the prodrug nanoparticles with the specific binding ability to neurophilin-1 receptor. In acid mediums, doxorubicin could be released from the prodrug nanoparticles with an accumulative release around 60% through the acid-triggered hydrolysis of cis-aconityl bond and nanoparticle disassembly. Whereas, drug release was slow under a neutral pH and the accumulative drug release was less than 16%. In the cell culture tests, our prodrug nanoparticles showed enhanced endocytosis and cytotoxicity in cancer cells including HepG2, MCF-7 and MDA-MB-231 cells, but lower cytotoxicity in human cardiomyocyte H2C9. In the animal experiments, the prodrug nanoparticles were intravenously injected into Balb/c nude mice bearing MDA-MB-231 tumors. Enhanced drug penetration and accumulation in tumors, accompanying with a rapid early tumor-binding behavior, was observed after intravenous injection of the peptide modified prodrug nanoparticles. These data suggests that the acid-sensitive and tumor-targeting PEGylated doxorubicin prodrug nanoparticle may be an efficient drug delivery system for cancer chemotherapy.

  3. Mechanisms of G Protein-Coupled Estrogen Receptor-Mediated Spinal Nociception

    DEFF Research Database (Denmark)

    Deliu, Elena; Brailoiu, G. Cristina; Arterburn, Jeffrey B.;

    2012-01-01

    Human and animal studies suggest that estrogens are involved in the processing of nociceptive sensory information and analgesic responses in the central nervous system. Rapid pronociceptive estrogenic effects have been reported, some of which likely involve G protein-coupled estrogen receptor (GPER...... in spinal nociceptive processing. Intrathecal challenging of mice with the GPER agonist G-1 results in pain-related behaviors. GPER antagonism with G15 reduces the G-1-induced response. Electrophysiological recordings from superficial dorsal horn neurons indicate neuronal membrane depolarization with G-1...... application, which is G15 sensitive. In cultured spinal sensory neurons, G-1 increases intracellular calcium concentration and induces mitochondrial and cytosolic ROS accumulation. In the presence of G15, G-1 does not elicit the calcium and ROS responses, confirming specific GPER involvement in this process...

  4. How toxic is oil? Investigating specific receptor-mediated toxic effects of crude and refined oils

    OpenAIRE

    Vrabie, C.M.

    2011-01-01

    Crude oils and refined oil products are major pollutants of the environment. Large oil spills, such as the recent blowout of the Deepwater Horizon in the Gulf of Mexico, raise concerns about the long term health effects of petroleum hydrocarbon exposure on wildlife and humans. In the environmental risk assessment of oils, narcosis (the disruption of an organism’s membrane structure) is the only mode of action assumed to determine the toxicity of petroleum hydrocarbons. However, several crude ...

  5. Receptor-mediated radiotherapy with 90Y-DOTA-D-Phe1-Tyr3-octreotide

    International Nuclear Information System (INIS)

    A newly developed somatostatin radioligand, DOTA-[D-Phe1-Tyr3]-octreotide (DOTATOC), has been synthesised for therapeutic purposes, because of its stable and easy labelling with yttrium-90. The aim of this study was to determine the dosage, safety profile and therapeutic efficacy of 90Y-DOTATOC in patients with cancers expressing somatostatin receptors. We recruited 30 patients with histologically confirmed cancer. The main inclusion criterion was the presence of somatostatin receptors as documented by 111In-DOTATOC scintigraphy. 90Y-DOTATOC was injected intravenously using a horizontal protocol: patients received equivalent-activity doses in each of three cycles over 6 months. The first six patients received 1.11 GBq per cycle and the four successive groups of six patients received doses increasing in 0.37-GBq steps. Toxicity was evaluated according to WHO criteria. No patient had acute or delayed adverse reactions up to 2.59 GBq 90Y-DOTATOC per cycle (total 7.77 GBq). After a total dose of 3.33 GBq, one patient developed grade II renal toxicity 6 months later. The maximum tolerated dose per cycle has not yet been reached, although transient lymphocytopenia has been observed. Total injectable activity is limited by the fact that the maximum dose tolerated by the kidneys has been estimated at 20-25 Gy. Complete or partial tumour mass reduction occurred in 23% of patients; 64% had stable and 13% progressive disease. It is concluded that high activities of 90Y-DOTATOC can be administered with a low risk of myelotoxicity, although the cumulative radiation dose to the kidneys is a limiting factor and requires careful evaluation. Objective therapeutic responses have been observed. (orig.)

  6. Vacuolar Sorting Receptor-Mediated Trafficking of Soluble Vacuolar Proteins in Plant Cells

    Directory of Open Access Journals (Sweden)

    Hyangju Kang

    2014-08-01

    Full Text Available Vacuoles are one of the most prominent organelles in plant cells, and they play various important roles, such as degradation of waste materials, storage of ions and metabolites, and maintaining turgor. During the past two decades, numerous advances have been made in understanding how proteins are specifically delivered to the vacuole. One of the most crucial steps in this process is specific sorting of soluble vacuolar proteins. Vacuolar sorting receptors (VSRs, which are type I membrane proteins, are involved in the sorting and packaging of soluble vacuolar proteins into transport vesicles with the help of various accessory proteins. To date, large amounts of data have led to the development of two different models describing VSR-mediated vacuolar trafficking that are radically different in multiple ways, particularly regarding the location of cargo binding to, and release from, the VSR and the types of carriers utilized. In this review, we summarize current literature aimed at elucidating VSR-mediated vacuolar trafficking and compare the two models with respect to the sorting signals of vacuolar proteins, as well as the molecular machinery involved in VSR-mediated vacuolar trafficking and its action mechanisms.

  7. Hypothyroidism Affects D2 Receptor-mediated Breathing without altering D2 Receptor Expression

    OpenAIRE

    Schlenker, Evelyn H; Rio, Rodrigo Del; Schultz, Harold D.

    2014-01-01

    Bromocriptine depressed ventilation in air and D2 receptor expression in the nucleus tractus solitaries (NTS) in male hypothyroid hamsters. Here we postulated that in age- matched hypothyroid female hamsters, the pattern of D2 receptor modulation of breathing and D2 receptor expression would differ from those reported in hypothyroid males. In females hypothyroidism did not affect D2 receptor protein levels in the NTS, carotid bodies or striatum. Bromocriptine, but not carmoxirole (a periphera...

  8. THIP, a hypnotic and antinociceptive drug, enhances a tonic GABAA receptor mediated conductance in mouse neocortex

    DEFF Research Database (Denmark)

    Drasbek, Kim Ryun; Jensen, Kimmo

    2006-01-01

    THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) is a selective GABA(A) receptor agonist with a preference for delta-subunit containing GABA(A) receptors. THIP is currently being tested in human trials for its hypnotic effects, displaying advantageous tolerance and addiction properties. Since...

  9. Potential insight for drug discovery from high fidelity receptor-mediated transduction mechanisms in insects

    Science.gov (United States)

    Raffa, Robert B.; Raffa, Kenneth F.

    2011-01-01

    Introduction There is a pervasive and growing concern about the small number of new pharmaceutical agents. There are many proposed explanations for this trend that do not involve the drug-discovery process per se, but the discovery process itself has also come under scrutiny. If the current paradigms are indeed not working, where are novel ideas to come from? Perhaps it is time to look to novel sources. Areas covered The receptor-signaling and 2nd-messenger transduction processes present in insects are quite similar to those in mammals (involving G proteins, ion channels, etc.). However, a review of these systems reveals an unprecedented degree of high potency and receptor selectivity to an extent greater than that modeled in most current drug-discovery approaches. Expert opinion A better understanding of insect receptor pharmacology could stimulate novel theoretical and practical ideas in mammalian pharmacology (drug discovery) and, conversely, the application of pharmacology and medicinal chemistry principles could stimulate novel advances in entomology (safer and more targeted control of pest species). PMID:21984882

  10. Monoolein-based nanocarriers for enhanced folate receptor-mediated RNA delivery to cancer cells.

    Science.gov (United States)

    Lopes, Ivo; C N Oliveira, Ana; P Sárria, Marisa; P Neves Silva, João; Gonçalves, Odete; Gomes, Andreia C; Real Oliveira, Maria Elisabete C D

    2016-09-01

    We report the development and characterization of a novel nanometric system for specific delivery of therapeutic siRNA for cancer treatment. This vector is based on a binary mixture of the cationic surfactant dioctadecyldimethylammonium chloride (DODAC) and the helper lipid monoolein (MO). These liposomes were previously validated by our research group as promising non-viral vectors for nucleic acid delivery. In this work, the DODAC:MO vesicles were for the first time functionalized with polyethylene glycol and PEG-folate conjugates to achieve both maximal stability in biological fluids and increase selectivity toward folate receptor α expressing cells. The produced DODAC:MO:PEG liposomes were highly effective in RNA complexation (close to 100%), and the resulting lipoplexes also demonstrated high stability in conditions simulating their administration by intravenous injection (physiological pH, high NaCl, heparin and fetal bovine serum concentrations). In addition, cell uptake of the PEG-folate-coated lipoplexes was significantly greater in folate receptor α positive breast cancer cells (39% for 25 µg/mL of lipid and 31% for 40 µg/mL) when compared with folate receptor α negative cells (31% for 25 µg/mL of lipid and 23% for 40 µg/mL) and to systems without PEG-folate (≈13% to 16% for all tested conditions), supporting their selectivity towards the receptor. Overall, the results support these systems as appealing vectors for selective delivery of siRNA to cancer cells by folate receptor α-mediated internalization, aiming at future therapeutic applications of interest. PMID:26340109

  11. Evidence that 5-hydroxytryptamine/sub 3/ receptors mediate cytotoxic drug and radiation-evoked emesis

    Energy Technology Data Exchange (ETDEWEB)

    Miner, W.D.; Sanger, G.J.; Turner, D.H.

    1987-08-01

    The involvement of 5-hydroxytryptamine (5-HT) 5-HT/sub 3/ receptors in the mechanisms of severe emesis evoked by cytotoxic drugs or by total body irradiation have been studied in ferrets. Anti-emetic compounds tested were domperidone (a dopamine antagonist), metoclopramide (a gastric motility stimulant and dopamine antagonist at conventional doses, a 5-HT/sub 3/ receptor antagonist at higher doses) and BRL 24924 (a potent gastric motility stimulant and a 5-HT/sub 3/ receptor antagonist). Domperidone or metoclopramide prevented apomorphine-evoked emesis, whereas BRL 24924 did not. Similar doses of domperidone did not prevent emesis evoked by cis-platin or by total body irradiation, whereas metoclopramide or BRL 24924 greatly reduced or prevented these types of emesis. Metoclopramide and BRL 24924 also prevented emesis evoked by a combination of doxorubicin and cyclophosphamide. These results are discussed in terms of a fundamental role for 5-HT/sub 3/ receptors in the mechanisms mediating severely emetogenic cancer treatment therapies.

  12. Androgen Receptors Mediate Masculinization of Astrocytes in the Rat Posterodorsal Medial Amygdala During Puberty

    OpenAIRE

    JOHNSON, RYAN T.; Breedlove, S. Marc; Jordan, Cynthia L.

    2013-01-01

    Astrocytes in the posterodorsal portion of the medial amygdala (MePD) are sexually dimorphic in adult rats: males have more astrocytes in the right MePD and more elaborate processes in the left MePD than do females. Functional androgen receptors (ARs) are required for masculinization of MePD astrocytes, as these measures are demasculinized in adult genetic males carrying the testicular feminization mutation (Tfm) of the AR gene, which renders AR dysfunctional. We now report that the number of...

  13. Orexin-1 Receptor Mediation of Cocaine Seeking in Male and Female Rats

    OpenAIRE

    Zhou, Luyi; Ghee, Shannon M.; Chan, Clifford; Lin, Li; Cameron, Michael D.; Kenny, Paul J.; See, Ronald E.

    2012-01-01

    Previous studies have shown that female rats exhibit enhanced cocaine seeking during multiple phases of cocaine addiction compared with males. The orexin/hypocretin system recently has been implicated in drug addiction in male rats. Based on the known sex differences in cocaine addiction, in the current study we examined orexin-mediated cocaine seeking during self-administration, extinction, and reinstatement in age-matched male (initial weight 250–300 g) and female (initial weight 175–225 g)...

  14. Progesterone stimulates respiration through a central nervous system steroid receptor-mediated mechanism in cat.

    OpenAIRE

    Bayliss, D A; Millhorn, D E; Gallman, E A; Cidlowski, J A

    1987-01-01

    We have examined the effect on respiration of the steroid hormone progesterone, administered either intravenously or directly into the medulla oblongata in anesthetized and paralyzed male and female cats. The carotid sinus and vagus nerves were cut, and end-tidal PCO2 and temperature were kept constant with servo-controllers. Phrenic nerve activity was used to quantitate central respiratory activity. Repeated doses of progesterone (from 0.1 to 2.0 micrograms/kg, cumulative) caused a sustained...

  15. Role of the Ventral Tegmental Area in Methamphetamine Extinction: AMPA Receptor-Mediated Neuroplasticity

    Science.gov (United States)

    Chen Han-Ting; Chen, Jin-Chung

    2015-01-01

    The molecular mechanisms underlying drug extinction remain largely unknown, although a role for medial prefrontal cortex (mPFC) glutamate neurons has been suggested. Considering that the mPFC sends glutamate efferents to the ventral tegmental area (VTA), we tested whether the VTA is involved in methamphetamine (METH) extinction via conditioned…

  16. 5-Hydroxytryptamine Receptors Mediating Carotid and Systemic Haemodynamic Effects: The Relation to Acute Antimigraine Therapy

    NARCIS (Netherlands)

    P. de Vries (Peter)

    1999-01-01

    textabstractThe presence of a vasoconstrictor substance in blood was suspected for 130 years (Ludwig & Schmidt, 1868) and, 50 years ago, Page and associates at the Cleveland Clinic (Cleveland, Ohio, USA) succeeded in isolating 'serotonin' from the blood (Rapport et al., 1948). Within the next 3 year

  17. Gamma interferon augments Fc gamma receptor-mediated dengue virus infection of human monocytic cells.

    OpenAIRE

    Kontny, U; Kurane, I; Ennis, F A

    1988-01-01

    It has been reported that anti-dengue antibodies at subneutralizing concentrations augment dengue virus infection of monocytic cells. This is due to the increased uptake of dengue virus in the form of virus-antibody complexes by cells via Fc gamma receptors. We analyzed the effects of recombinant human gamma interferon (rIFN-gamma) on dengue virus infection of human monocytic cells. U937 cells, a human monocytic cell line, were infected with dengue virus in the form of virus-antibody complexe...

  18. Valerian inhibits rat hepatocarcinogenesis by activating GABA(A) receptor-mediated signaling.

    Science.gov (United States)

    Kakehashi, Anna; Kato, Ayumi; Ishii, Naomi; Wei, Min; Morimura, Keiichirou; Fukushima, Shoji; Wanibuchi, Hideki

    2014-01-01

    Valerian is widely used as a traditional medicine to improve the quality of sleep due to interaction of several active components with the γ-aminobutyric acid (GABA) A receptor (GABA(A)R) system. Recently, activation of GABA signaling in stem cells has been reported to suppress cell cycle progression in vivo. Furthermore, possible inhibitory effects of GABA(A)R agonists on hepatocarcinogenesis have been reported. The present study was performed to investigate modulating effects of Valerian on hepatocarcinogenesis using a medium-term rat liver bioassay. Male F344 rats were treated with one of the most powerful Valerian species (Valeriana sitchensis) at doses of 0, 50, 500 and 5000 ppm in their drinking water after initiation of hepatocarcinogenesis with diethylnitrosamine (DEN). Formation of glutathione S-transferase placental form positive (GST-P(+)) foci was significantly inhibited by Valerian at all applied doses compared with DEN initiation control rats. Generation of 8-hydroxy-2'-deoxyguanosine in the rat liver was significantly suppressed by all doses of Valerian, likely due to suppression of Nrf2, CYP7A1 and induction of catalase expression. Cell proliferation was significantly inhibited, while apoptosis was induced in areas of GST-P(+) foci of Valerian groups associated with suppression of c-myc, Mafb, cyclin D1 and induction of p21(Waf1/Cip1), p53 and Bax mRNA expression. Interestingly, expression of the GABA(A)R alpha 1 subunit was observed in GST-P(+) foci of DEN control rats, with significant elevation associated with Valerian treatment. These results indicate that Valerian exhibits inhibitory effects on rat hepatocarcinogenesis by inhibiting oxidative DNA damage, suppressing cell proliferation and inducing apoptosis in GST-P(+) foci by activating GABA(A)R-mediated signaling. PMID:25419570

  19. A possibly sigma-1 receptor mediated role of dimethyltryptamine in tissue protection, regeneration, and immunity.

    Science.gov (United States)

    Frecska, Ede; Szabo, Attila; Winkelman, Michael J; Luna, Luis E; McKenna, Dennis J

    2013-09-01

    N,N-dimethyltryptamine (DMT) is classified as a naturally occurring serotonergic hallucinogen of plant origin. It has also been found in animal tissues and regarded as an endogenous trace amine transmitter. The vast majority of research on DMT has targeted its psychotropic/psychedelic properties with less focus on its effects beyond the nervous system. The recent discovery that DMT is an endogenous ligand of the sigma-1 receptor may shed light on yet undiscovered physiological mechanisms of DMT activity and reveal some of its putative biological functions. A three-step active uptake process of DMT from peripheral sources to neurons underscores a presumed physiological significance of this endogenous hallucinogen. In this paper, we overview the literature on the effects of sigma-1 receptor ligands on cellular bioenergetics, the role of serotonin, and serotoninergic analogues in immunoregulation and the data regarding gene expression of the DMT synthesizing enzyme indolethylamine-N-methyltransferase in carcinogenesis. We conclude that the function of DMT may extend central nervous activity and involve a more universal role in cellular protective mechanisms. Suggestions are offered for future directions of indole alkaloid research in the general medical field. We provide converging evidence that while DMT is a substance which produces powerful psychedelic experiences, it is better understood not as a hallucinogenic drug of abuse, but rather an agent of significant adaptive mechanisms that can also serve as a promising tool in the development of future medical therapies. PMID:23619992

  20. Characterization of the 5-HT4 receptor mediating tachycardia in piglet isolated right atrium.

    OpenAIRE

    Medhurst, A. D.; Kaumann, A J

    1993-01-01

    1. In order to explore whether 5-HT4 receptor subtypes exist, we have characterized further the 5-HT4 receptor that mediates tachycardia in the piglet isolated right atrium. All experiments were carried out in the presence of propranolol (400 nM) and cocaine (6 microM). We used tryptamine derivatives, substituted benzamides and benzimidazolone derivatives as pharmacological tools. 2. Tachycardia responses to 5-hydroxytryptamine (5-HT) were mimicked by other tryptamine derivatives with the fol...

  1. Signal transduction in cultered cardiomyocytes : alpha1-adrenergic and endothelin receptor mediated responses

    NARCIS (Netherlands)

    H.W. de Jonge (Jet)

    1996-01-01

    textabstractAlready in ancient times the Greek were aware of the heart in the human body and they gave it the name kardia, which is still in use in words as cardiac, myocardial, tachycardia and bradycardia. In those times the importance of the heart was appraised by Aristotle (384-322 B.C.), who tho

  2. Capillary morphogenesis protein-2 is the major receptor mediating lethality of anthrax toxin in vivo

    OpenAIRE

    Liu, Shihui; Crown, Devorah; Miller-Randolph, Sharmina; Moayeri, Mahtab; Wang, Hailun; Hu, Haijing; Morley, Thomas; Leppla, Stephen H.

    2009-01-01

    Anthrax toxin, a major virulence factor of Bacillus anthracis, gains entry into target cells by binding to either of 2 von Willebrand factor A domain-containing proteins, tumor endothelium marker-8 (TEM8) and capillary morphogenesis protein-2 (CMG2). The wide tissue expression of TEM8 and CMG2 suggest that both receptors could play a role in anthrax pathogenesis. To explore the roles of TEM8 and CMG2 in normal physiology, as well as in anthrax pathogenesis, we generated TEM8- and CMG2-null mi...

  3. CB1 cannabinoid receptor-mediated modulation of food intake in mice

    OpenAIRE

    Wiley, Jenny L; Burston, James J.; Leggett, Darnica C; Alekseeva, Olga O; Razdan, Raj K.; Mahadevan, Anu; Martin, Billy R

    2005-01-01

    Marijuana's appetite-increasing effects have long been known. Recent research suggests that the CB1 cannabinoid receptor antagonist SR141716A may suppress appetite. This study represents a further, systematic investigation of the role of CB1 cannabinoid receptors in the pharmacological effects of cannabinoids on food intake.Mice were food-restricted for 24 h and then allowed access to their regular rodent chow for 1 h. Whereas the CB1 antagonist SR141716A dose-dependently decreased food consu...

  4. P2X7 receptor-mediated analgesia in cancer-induced bone pain

    DEFF Research Database (Denmark)

    Falk, Sarah; D. Schwab, Samantha; Frøsig-Jørgensen, Majbrit;

    2015-01-01

    to low intensity or electrical stimulation. In contrast, A839977 had no effect on the tested parameters in naïve or sham animals. In awake animals, 40mg/kg A839977 (i.p) significantly reduced both early and late stage pain behavior. In contrast, no effect was observed in sham or vehicle-treated animals....... The results suggest that the P2X7R is involved in the mechanisms of cancer-induced bone pain, and that P2X7R antagonism might be a useful analgesic target. No effect was observed in sham or naïve animals, indicating that the P2X7R-mediated effect is state-dependent, and might therefore be an advantageous......Pain is a common and debilitating complication for cancer patients significantly compromising their quality of life. Cancer-induced bone pain involves a complex interplay of molecular events, including mechanisms observed in inflammatory and neuropathic pain states, but also changes unique...

  5. Melanocortin-1 receptor-mediated signalling pathways activated by NDP-MSH and HBD3 ligands

    OpenAIRE

    Beaumont, Kimberley A.; Smit, Darren J.; Liu, Yan Yan; Chai, Eric; Patel, Mira P.; Millhauser, Glenn L.; Smith, Jennifer J.; Alewood, Paul F.; Sturm, Richard A.

    2012-01-01

    Binding of melanocortin peptide agonists to the melanocortin-1 receptor of melanocytes results in eumelanin production, whereas binding of the agouti signalling protein inverse agonist results in pheomelanin synthesis. Recently, a novel melanocortin-1 receptor ligand was reported. A β-defensin gene mutation was found to beresponsible for black coat colour in domestic dogs. Notably, the human equivalent, β-defensin 3, was found to bind with high affinity to the melanocortin-1 receptor; however...

  6. Opioid Receptors Mediate Direct Predictive Fear Learning: Evidence from One-Trial Blocking

    Science.gov (United States)

    Cole, Sindy; McNally, Gavan P.

    2007-01-01

    Pavlovian fear learning depends on predictive error, so that fear learning occurs when the actual outcome of a conditioning trial exceeds the expected outcome. Previous research has shown that opioid receptors, including [mu]-opioid receptors in the ventrolateral quadrant of the midbrain periaqueductal gray (vlPAG), mediate such predictive fear…

  7. System theoretical investigation of human epidermal growth factor receptor-mediated signalling

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yi; Shankaran, Harish; Opresko, Lee; Resat, Haluk

    2008-09-01

    The partitioning of biological networks into coupled functional modules is gaining increasing attention in the biological sciences. This approach has the advantage that predicting a system level response does not require a mechanistic description of the internal dynamics of each module. Identification of the input-output characteristics of the network modules and the connectivity between the modules provide the necessary quantitative representation of system dynamics. However, determination of the input-output relationships of the modules is not trivial; it requires the controlled perturbation of module inputs and systematic analysis of experimental data. In this report, we apply a system theoretical analysis approach to derive the causal input-output relationships of the functional module for the human epidermal growth factor receptor (HER) mediated Erk and Akt signaling pathways. Using a library of cell lines expressing varying levels of EGFR and HER2, we show that a transfer function-based representation can be successfully applied to quantitatively characterize information transfer in this system.

  8. A novel gliotic P2 receptor mediating cyclooxygenase-2 induction in rat and human astrocytes.

    Science.gov (United States)

    Brambilla, R; Ceruti, S; Malorni, W; Cattabeni, F; Abbracchio, M P

    2000-07-01

    In astrocytic cultures maintained in vitro, a brief challenge with the ATP analog alpha,beta methyleneATP (alpha,betameATP) results, 3 days later, in marked elongation of astrocytic processes, an event that resembles the astrocytic hypertrophy known to occur in vivo during reactive astrogliosis. alpha,beta meATP-induced effects were observed in primary astrocytes obtained from both rat striatum and cortex (a brain area highly involved in chronic neurodegenerative pathologies), as well as in human astrocytoma cells (ADF cells). Purine-induced gliosis could be reversed by the non-selective P2X/P2Y receptor antagonist pyridoxalphosphate-6-azophenyl-2', 4'-disulphonic acid (PPADS), but not by oxidized ATP (an antagonist of the P2X(7) receptor), in line with previous studies of our laboratory suggesting the involvement of a P2Y receptor subtype. Induction of reactive gliosis was preceded by increased expression of cyclooxygenase-2 (COX-2), an enzyme whose excessive activation has been implicated in both acute and chronic neurodegenerative diseases. The selective COX-2 inhibitor NS-398 prevented both purine-induced astrogliosis and the associated COX-2 induction, suggesting that inhibition of the transcription of the COX-2 gene may also contribute to the anti-inflammatory properties of this agent. Significant blockade of both alpha,beta meATP-mediated reactive gliosis and COX-2 induction was also observed with PPADS. These data suggest that COX-2 mediates P2Y receptor-induced reactive astrogliosis, and that antagonists selective for this receptor subtype may represent a novel class of anti-inflammatory agents of potential interest in acute and chronic neurological disorders characterized by an inflammatory component and reactive gliosis.

  9. P2X receptors mediate ATP-induced primary nociceptive neurone activation.

    Science.gov (United States)

    Bland-Ward, P A; Humphrey, P P

    2000-07-01

    ATP-gated P2X ion-channel receptors are localised throughout the mammalian nervous system and have been identified on neurones which participate in conduction of nociceptive information from the periphery to, and within, the CNS. This article briefly reviews recently published research describing the role that ATP and P2X receptors may play in pain perception, highlighting the importance of the P2X(3) receptor in this process. The P2X(3) receptor subunit is almost exclusively expressed on a subset of small and medium diameter sensory neurones innervating cutaneous and visceral tissue. Activation of P2X receptors present on the peripheral terminals of primary afferents results in neuronal depolarisation and, in conscious animals, leads to the manifestation of acute nociceptive behaviour. Recent animal studies have also shown that P2X(3) receptor expression is increased in sensory ganglia following acute neuronal injury, hinting that similar plasticity in the expression of this receptor subtype could underlie the mechanisms involved in a range of conditions characterised by sensory hypersensitivity in man. It is apparent from the evidence available that functional antagonists at specific P2X receptor subtypes could represent an important class of novel analgesic agents.

  10. Hindbrain GLP-1 receptor mediation of cisplatin-induced anorexia and nausea.

    Science.gov (United States)

    De Jonghe, Bart C; Holland, Ruby A; Olivos, Diana R; Rupprecht, Laura E; Kanoski, Scott E; Hayes, Matthew R

    2016-01-01

    While chemotherapy-induced nausea and vomiting are clinically controlled in the acute (anorexia, nausea, fatigue, and other illness-type behaviors during the delayed phase (>24 h) of chemotherapy are largely uncontrolled. As the hindbrain glucagon-like peptide-1 (GLP-1) system contributes to energy balance and mediates aversive and stressful stimuli, here we examine the hypothesis that hindbrain GLP-1 signaling mediates aspects of chemotherapy-induced nausea and reductions in feeding behavior in rats. Specifically, hindbrain GLP-1 receptor (GLP-1R) blockade, via 4th intracerebroventricular (ICV) exendin-(9-39) injections, attenuates the anorexia, body weight reduction, and pica (nausea-induced ingestion of kaolin clay) elicited by cisplatin chemotherapy during the delayed phase (48 h) of chemotherapy-induced nausea. Additionally, the present data provide evidence that the central GLP-1-producing preproglucagon neurons in the nucleus tractus solitarius (NTS) of the caudal brainstem are activated by cisplatin during the delayed phase of chemotherapy-induced nausea, as cisplatin led to a significant increase in c-Fos immunoreactivity in NTS GLP-1-immunoreactive neurons. These data support a growing body of literature suggesting that the central GLP-1 system may be a potential pharmaceutical target for adjunct anti-emetics used to treat the delayed-phase of nausea and emesis, anorexia, and body weight loss that accompany chemotherapy treatments.

  11. Thyrotropin modulates receptor-mediated processing of the atrial natriuretic peptide receptor in cultured thyroid cells

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, Y.L.; Burman, K.D.; Lahiri, S.; Abdelrahim, M.M.; D' Avis, J.C.; Wartofsky, L. (Walter Reed Army Medical Center, Washington, DC (USA))

    1991-03-01

    In a prior study of atrial natriuretic peptide (ANP) binding to cultured thyroid cells, we reported that at 4 C, more than 95% of bound ANP is recovered on cell membranes, with negligible ANP internalization observed. Since ANP binding was inhibited by TSH, we have further studied TSH effects on postbinding ANP processing to determine whether this phenomenon reflects enhanced endocytosis of the ANP-receptor complex. An ANP chase study was initiated by binding (125I) ANP to thyroid cells at 4 C for 2 h, followed by incubation at 37 C. ANP processing was then traced by following 125I activity at various time intervals in three fractions: cell surface membranes, incubation medium, and inside the cells. Radioactivity released into medium represented processed ANP rather than ANP dissociated from surface membranes, since prebound (125I)ANP could not be competitively dissociated by a high concentration of ANP (1 mumol/L) at 37 C. Chase study results showed that prebound ANP quickly disappeared from cell membranes down to 34% by 30 min. Internalized ANP peaked at 10 min, with 21% of initial prebound ANP found inside the cells. At the same time, radioactivity recovered in incubation medium sharply increased between 10-30 min from 8% to 52%. Preincubation of cells with chloroquine (which blocks degradation of the ANP-receptor complex by inhibiting lysosomal hydrolase) caused a 146% increase in internalized (125I)ANP by 30 min (39% compared to 15% control), while medium radioactivity decreased from 52% to 16%, suggesting that processing of the receptor complex is mediated via lysosomal enzymes. In chase studies employing cells pretreated with chloroquine, TSH stimulated the internalization rate of ANP-receptor complex. By 30 min, TSH significantly reduced the membrane-bound ANP, and the decrease was inversely correlated to the increase in internalized radioactivity.

  12. Muscarinic acetylcholine receptor-mediated stimulation of retinal ganglion cell photoreceptors.

    Science.gov (United States)

    Sodhi, Puneet; Hartwick, Andrew T E

    2016-09-01

    Melanopsin-dependent phototransduction in intrinsically photosensitive retinal ganglion cells (ipRGCs) involves a Gq-coupled phospholipase C (PLC) signaling cascade. Acetylcholine, released in the mammalian retina by starburst amacrine cells, can also activate Gq-PLC pathways through certain muscarinic acetylcholine receptors (mAChRs). Using multielectrode array recordings of rat retinas, we demonstrate that robust spiking responses can be evoked in neonatal and adult ipRGCs after bath application of the muscarinic agonist carbachol. The stimulatory action of carbachol on ipRGCs was a direct effect, as confirmed through calcium imaging experiments on isolated ipRGCs in purified cultures. Using flickering (6 Hz) yellow light stimuli at irradiances below the threshold for melanopsin activation, spiking responses could be elicited in ipRGCs that were suppressed by mAChR antagonism. Therefore, this work identified a novel melanopsin-independent pathway for stimulating sustained spiking in ganglion cell photoreceptors. This mAChR-mediated pathway could enhance ipRGC spiking responses in conditions known to evoke retinal acetylcholine release, such as those involving flickering or moving visual stimuli. Furthermore, this work identifies a pharmacological approach for light-independent ipRGC stimulation that could be targeted by mAChR agonists. PMID:27055770

  13. The Fc and not CD4 Receptor Mediates Antibody Enhancement of HIV Infection in Human Cells

    Science.gov (United States)

    Homsy, Jacques; Meyer, Mia; Tateno, Masatoshi; Clarkson, Sarah; Levy, Jay A.

    1989-06-01

    Antibodies that enhance human immunodeficiency virus (HIV) infectivity have been found in the blood of infected individuals and in infected or immunized animals. These findings raise serious concern for the development of a safe vaccine against acquired immunodeficiency syndrome. To address the in vivo relevance and mechanism of this phenomenon, antibody-dependent enhancement of HIV infectivity in peripheral blood macrophages, lymphocytes, and human fibroblastoid cells was studied. Neither Leu3a, a monoclonal antibody directed against the CD4 receptor, nor soluble recombinant CD4 even at high concentrations prevented this enhancement. The addition of monoclonal antibody to the Fc receptor III (anti-FcRIII), but not of antibodies that react with FcRI or FcRII, inhibited HIV type 1 and HIV type 2 enhancement in peripheral blood macrophages. Although enhancement of HIV infection in CD4+ lymphocytes could not be blocked by anti-FcRIII, it was inhibited by the addition of human immunoglobulin G aggregates. The results indicate that the FcRIII receptor on human macrophages and possibly another Fc receptor on human CD4+ lymphocytes mediate antibody-dependent enhancement of HIV infectivity and that this phenomenon proceeds through a mechanism independent of the CD4 protein.

  14. Antibody therapy of cancer : Fc receptor-mediated mechanisms of action

    NARCIS (Netherlands)

    Overdijk, M.B.

    2013-01-01

    Cancer, a class of malignant diseases characterized by unregulated cell growth, is still a leading cause of death worldwide. The high specificity of antibodies combined with the ability to engage multiple mechanisms of action (MoA) and minimal side-effects makes them attractive agents for targeted t

  15. Insulin receptors mediate growth effects in cultured fetal neurons. I. Rapid stimulation of protein synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Heidenreich, K.A.; Toledo, S.P. (Univ. of California-San Diego, La Jolla (USA))

    1989-09-01

    In this study we have examined the effects of insulin on protein synthesis in cultured fetal chick neurons. Protein synthesis was monitored by measuring the incorporation of (3H)leucine (3H-leu) into trichloroacetic acid (TCA)-precipitable protein. Upon addition of 3H-leu, there was a 5-min lag before radioactivity occurred in protein. During this period cell-associated radioactivity reached equilibrium and was totally recovered in the TCA-soluble fraction. After 5 min, the incorporation of 3H-leu into protein was linear for 2 h and was inhibited (98%) by the inclusion of 10 micrograms/ml cycloheximide. After 24 h of serum deprivation, insulin increased 3H-leu incorporation into protein by approximately 2-fold. The stimulation of protein synthesis by insulin was dose dependent (ED50 = 70 pM) and seen within 30 min. Proinsulin was approximately 10-fold less potent than insulin on a molar basis in stimulating neuronal protein synthesis. Insulin had no effect on the TCA-soluble fraction of 3H-leu at any time and did not influence the uptake of (3H)aminoisobutyric acid into neurons. The isotope ratio of 3H-leu/14C-leu in the leucyl tRNA pool was the same in control and insulin-treated neurons. Analysis of newly synthesized proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that insulin uniformly increased the incorporation of 14C-leu into all of the resolved neuronal proteins. We conclude from these data that (1) insulin rapidly stimulates overall protein synthesis in fetal neurons independent of amino acid uptake and aminoacyl tRNA precursor pools; (2) stimulation of protein synthesis is mediated by the brain subtype of insulin receptor; and (3) insulin is potentially an important in vivo growth factor for fetal central nervous system neurons.

  16. Insulin receptors mediate growth effects in cultured fetal neurons. I. Rapid stimulation of protein synthesis

    International Nuclear Information System (INIS)

    In this study we have examined the effects of insulin on protein synthesis in cultured fetal chick neurons. Protein synthesis was monitored by measuring the incorporation of [3H]leucine (3H-leu) into trichloroacetic acid (TCA)-precipitable protein. Upon addition of 3H-leu, there was a 5-min lag before radioactivity occurred in protein. During this period cell-associated radioactivity reached equilibrium and was totally recovered in the TCA-soluble fraction. After 5 min, the incorporation of 3H-leu into protein was linear for 2 h and was inhibited (98%) by the inclusion of 10 micrograms/ml cycloheximide. After 24 h of serum deprivation, insulin increased 3H-leu incorporation into protein by approximately 2-fold. The stimulation of protein synthesis by insulin was dose dependent (ED50 = 70 pM) and seen within 30 min. Proinsulin was approximately 10-fold less potent than insulin on a molar basis in stimulating neuronal protein synthesis. Insulin had no effect on the TCA-soluble fraction of 3H-leu at any time and did not influence the uptake of [3H]aminoisobutyric acid into neurons. The isotope ratio of 3H-leu/14C-leu in the leucyl tRNA pool was the same in control and insulin-treated neurons. Analysis of newly synthesized proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that insulin uniformly increased the incorporation of 14C-leu into all of the resolved neuronal proteins. We conclude from these data that (1) insulin rapidly stimulates overall protein synthesis in fetal neurons independent of amino acid uptake and aminoacyl tRNA precursor pools; (2) stimulation of protein synthesis is mediated by the brain subtype of insulin receptor; and (3) insulin is potentially an important in vivo growth factor for fetal central nervous system neurons

  17. Benzodiazepine receptor-mediated behavioral effects of nitrous oxide in the rat social interaction test.

    Science.gov (United States)

    Quock, R M; Wetzel, P J; Maillefer, R H; Hodges, B L; Curtis, B A; Czech, D A

    1993-09-01

    The present study was conducted to ascertain whether an anxiolytic effect of nitrous oxide was demonstrable in rats using the social interaction test and whether this drug effect might be mediated by benzodiazepine receptors. Compared to behavior of vehicle-pretreated, room air-exposed rats, rat pairs exposed to nitrous oxide showed a generally inverted U-shaped dose-response curve with the maximum increase in social interaction encounters occurring at 25% and significant increase in time of active social interaction at 15-35%; higher concentrations produced a sedative effect that reduced social interaction. Treatment with 5.0 mg/kg of the anxiolytic benzodiazepine chlordiazepoxide also increased social interaction. Pretreatment with 10 mg/kg of the benzodiazepine receptor blocker flumazenil, which alone had no effect, significantly antagonized the social interaction-increasing effects of both nitrous oxide and chlordiazepoxide. In summary, these findings suggest that nitrous oxide produces a flumazenil-sensitive effect comparable to that of chlordiazepoxide and implicate central benzodiazepine mechanisms in mediation of the anxiolytic effect of nitrous oxide.

  18. Role of NMDA Receptor-Mediated Glutamatergic Signaling in Chronic and Acute Neuropathologies

    Directory of Open Access Journals (Sweden)

    Francisco J. Carvajal

    2016-01-01

    Full Text Available N-Methyl-D-aspartate receptors (NMDARs have two opposing roles in the brain. On the one hand, NMDARs control critical events in the formation and development of synaptic organization and synaptic plasticity. On the other hand, the overactivation of NMDARs can promote neuronal death in neuropathological conditions. Ca2+ influx acts as a primary modulator after NMDAR channel activation. An imbalance in Ca2+ homeostasis is associated with several neurological diseases including schizophrenia, Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and amyotrophic lateral sclerosis. These chronic conditions have a lengthy progression depending on internal and external factors. External factors such as acute episodes of brain damage are associated with an earlier onset of several of these chronic mental conditions. Here, we will review some of the current evidence of how traumatic brain injury can hasten the onset of several neurological conditions, focusing on the role of NMDAR distribution and the functional consequences in calcium homeostasis associated with synaptic dysfunction and neuronal death present in this group of chronic diseases.

  19. Swim stress differentially blocks CRF receptor mediated responses in dorsal raphe nucleus.

    Science.gov (United States)

    Lamy, Christophe M; Beck, Sheryl G

    2010-10-01

    Modulation of the serotonergic (5-HT) neurotransmitter system arising from the dorsal raphe nucleus (DR) is thought to support the behavioral effects of swim stress, i.e., immobility. In vivo pharmacological and anatomical studies suggest that corticotropin-releasing factor (CRF) and γ-aminobutyric acid (GABA) synaptic transmission closely interact to set the response of the DR to swim stress. To investigate the cellular basis of these physiological mechanisms the effects of ovine CRF (oCRF) on GABA(A)-dependent miniature inhibitory postsynaptic currents (mIPSCs) in 5-HT and non-5-HT DR neurons in acute mesencephalic slices obtained from rats either naïve or 24h after a 15 min swim stress session were tested. In this study, the effect of swim stress alone was to decrease the holding current, i.e., hyperpolarize the neuron, and to increase the amplitude and charge of mIPSCs recorded from non-5-HT neurons. Ovine CRF (10 nM) induced an increase in mIPSC frequency in 5-HT neurons recorded from naïve rats, an effect that was suppressed by swim stress. The inward current elicited by oCRF in both 5-HT and non-5-HT neurons was also blocked by swim stress. Ovine CRF increased mIPSCs amplitude and charge in both 5-HT and non-5-HT neurons, but this effect was not modified by swim stress. In concert with our previous findings that swim stress decreased input resistance, action potential threshold and action potential duration and increased glutamatergic synaptic activity the overall primary effect of swim stress is to increase the excitability of 5-HT neurons. These data provide a mechanism at the cellular level for the immobility induced by swim stress and identifies critical components of the raphe circuitry responsible for the altered output of 5-HT neurons induced by swim stress.

  20. Downregulation of adenosine and P2X receptor-mediated cardiovascular responses in heart failure rats

    DEFF Research Database (Denmark)

    Zhao, Xin; Sun, X Y; Erlinge, D;

    2000-01-01

    Neurohormonal changes in congestive heart failure (CHF) include an enhanced peripheral sympathetic nerve activity which results in increased release of noradrenaline, neuropeptide Y and ATP. To examine if such changes in CHF would modulate peripheral pre- and postsynaptic receptors of ATP and its...... effects mediated by the endothelial P2Y receptors are unaffected in CHF. Moreover, the adenosine-mediated inhibitory effects on heart rate and blood pressure were also attenuated in the CHF rats. The most important changes in adenosine and P2-receptor function induced by ischaemic CHF were the reduced...... pressor effect mediated by the P2X receptor and the increased heart rate due to an attenuated inhibitory effect of adenosine....

  1. Receptor-mediated endocytosis of α-galactosidase A in human podocytes in Fabry disease

    DEFF Research Database (Denmark)

    Prabakaran, Thaneas; Nielsen, Rikke; Larsen, Jakob Vejby;

    2011-01-01

    Injury to the glomerular podocyte is a key mechanism in human glomerular disease and podocyte repair is an important therapeutic target. In Fabry disease, podocyte injury is caused by the intracellular accumulation of globotriaosylceramide. This study identifies in the human podocyte three endocy...

  2. Receptor-Mediated Endocytosis of α-Galactosidase A in Human Podocytes in Fabry Disease

    DEFF Research Database (Denmark)

    Prabakaran, Thaneas; Nielsen, Rikke; Larsen, Jakob Vejby;

    2011-01-01

    Injury to the glomerular podocyte is a key mechanism in human glomerular disease and podocyte repair is an important therapeutic target. In Fabry disease, podocyte injury is caused by the intracellular accumulation of globotriaosylceramide. This study identifies in the human podocyte three endocy...

  3. T-Cell Tumor Elimination as a Result of T-Cell Receptor-Mediated Activation

    Science.gov (United States)

    Ashwell, Jonathan D.; Longo, Dan L.; Bridges, Sandra H.

    1987-07-01

    It has recently been shown that activation of murine T-cell hybridomas with antigen inhibits their growth in vitro. The ``suicide'' of these neoplastic T cells upon stimulation with antigen suggested the possibility that activation via the antigen-specific receptor could also inhibit the growth of neoplastic T cells in vivo. To test this, mice were subcutaneously inoculated with antigen-specific T-cell hybridomas and then treated intraperitoneally with antigen. Administration of the appropriate antigen immediately after inoculation with the T-cell hybridoma abrogated tumor formation; antigen administered after tumors had become established decreased the tumor burden and, in a substantial fraction of animals, led to long-term survival. The efficacy of antigen therapy was due to both a direct inhibitory effect on tumor growth and the induction of host immunity. These studies demonstrate the utility of cellular activation as a means of inhibiting neoplastic T-cell growth in vivo and provide a rationale for studying the use of less selective reagents that can mimic the activating properties of antigen, such as monoclonal antibodies, in the treatment of T-cell neoplasms of unknown antigen specificity.

  4. Receptor-mediated endocytosis of diphtheria toxin by cells in culture.

    OpenAIRE

    Keen, J H; Maxfield, F R; Hardegree, M C; Habig, W H

    1982-01-01

    The binding and uptake of fluorescently labeled diphtheria toxin by cells in culture has been examined by using epifluorescence video intensification microscopy. Rhodamine-labeled diphtheria toxin retained significant toxicity on bioassay and in cell culture and was tested for uptake by human WI-38 and mouse 3T3 fibroblasts grown in culture. When added to cells at 37 degrees C, toxin was observed to become concentrated and internalized in discrete vesicles in both cell lines. The appearance o...

  5. Hindbrain GLP-1 receptor mediation of cisplatin-induced anorexia and nausea.

    Science.gov (United States)

    De Jonghe, Bart C; Holland, Ruby A; Olivos, Diana R; Rupprecht, Laura E; Kanoski, Scott E; Hayes, Matthew R

    2016-01-01

    While chemotherapy-induced nausea and vomiting are clinically controlled in the acute (24 h) of chemotherapy are largely uncontrolled. As the hindbrain glucagon-like peptide-1 (GLP-1) system contributes to energy balance and mediates aversive and stressful stimuli, here we examine the hypothesis that hindbrain GLP-1 signaling mediates aspects of chemotherapy-induced nausea and reductions in feeding behavior in rats. Specifically, hindbrain GLP-1 receptor (GLP-1R) blockade, via 4th intracerebroventricular (ICV) exendin-(9-39) injections, attenuates the anorexia, body weight reduction, and pica (nausea-induced ingestion of kaolin clay) elicited by cisplatin chemotherapy during the delayed phase (48 h) of chemotherapy-induced nausea. Additionally, the present data provide evidence that the central GLP-1-producing preproglucagon neurons in the nucleus tractus solitarius (NTS) of the caudal brainstem are activated by cisplatin during the delayed phase of chemotherapy-induced nausea, as cisplatin led to a significant increase in c-Fos immunoreactivity in NTS GLP-1-immunoreactive neurons. These data support a growing body of literature suggesting that the central GLP-1 system may be a potential pharmaceutical target for adjunct anti-emetics used to treat the delayed-phase of nausea and emesis, anorexia, and body weight loss that accompany chemotherapy treatments. PMID:26522737

  6. Valerian inhibits rat hepatocarcinogenesis by activating GABA(A receptor-mediated signaling.

    Directory of Open Access Journals (Sweden)

    Anna Kakehashi

    Full Text Available Valerian is widely used as a traditional medicine to improve the quality of sleep due to interaction of several active components with the γ-aminobutyric acid (GABA A receptor (GABA(AR system. Recently, activation of GABA signaling in stem cells has been reported to suppress cell cycle progression in vivo. Furthermore, possible inhibitory effects of GABA(AR agonists on hepatocarcinogenesis have been reported. The present study was performed to investigate modulating effects of Valerian on hepatocarcinogenesis using a medium-term rat liver bioassay. Male F344 rats were treated with one of the most powerful Valerian species (Valeriana sitchensis at doses of 0, 50, 500 and 5000 ppm in their drinking water after initiation of hepatocarcinogenesis with diethylnitrosamine (DEN. Formation of glutathione S-transferase placental form positive (GST-P(+ foci was significantly inhibited by Valerian at all applied doses compared with DEN initiation control rats. Generation of 8-hydroxy-2'-deoxyguanosine in the rat liver was significantly suppressed by all doses of Valerian, likely due to suppression of Nrf2, CYP7A1 and induction of catalase expression. Cell proliferation was significantly inhibited, while apoptosis was induced in areas of GST-P(+ foci of Valerian groups associated with suppression of c-myc, Mafb, cyclin D1 and induction of p21(Waf1/Cip1, p53 and Bax mRNA expression. Interestingly, expression of the GABA(AR alpha 1 subunit was observed in GST-P(+ foci of DEN control rats, with significant elevation associated with Valerian treatment. These results indicate that Valerian exhibits inhibitory effects on rat hepatocarcinogenesis by inhibiting oxidative DNA damage, suppressing cell proliferation and inducing apoptosis in GST-P(+ foci by activating GABA(AR-mediated signaling.

  7. Human neutrophil Fc receptor-mediated adhesion under flow: a hollow fibre model of intravascular arrest.

    Science.gov (United States)

    D'Arrigo, C; Candal-Couto, J J; Greer, M; Veale, D J; Woof, J M

    1995-04-01

    Human polymorphonuclear cells (PMN) were found to adhere to a novel model of blood vessel wall-associated IgG. The internal surfaces of cellulose acetate hollow fibres, of comparable internal diameter to small blood vessels, were coated with normal serum human IgG, heat-aggregated IgG (HAIgG), laminin or fibrinogen. Under conditions of flow mimicking those in a small vessel, PMN were found to adhere markedly only to immunoglobulin-coated fibres. Arrest on HAIgG was inhibited by excess soluble IgG but not by bovine serum albumin (BSA), demonstrating that the adhesion was IgG-specific and presumably mediated by Fc gamma R on the PMN surface. Pre-adsorption of serum components onto HAIgG-coated fibres enhanced PMN arrest, due most probably to fixation of complement components by immobilized HAIgG, resulting in additional potential to entrap PMN via complement receptors such as CR3. Treatment of PMN with the regulatory neuropeptide substance P also enhanced adhesion to HAIgG-coated fibres and caused increased surface expression of Fc gamma RI, Fc gamma RII and Fc gamma RIII. A mouse cell line derived from L cells, hR4C6, stably transfected with human Fc gamma RII, was found to adhere under flow to HAIgG-coated fibres, whilst untransfected parent L cells did not. This adhesion was similarly inhibited by excess soluble IgG, confirming the capability of Fc gamma R to mediate cell arrest. The study strongly suggests that Fc gamma R may play an important role in intravascular PMN arrest and we speculate that in inflammatory diseases PMN may adhere via Fc gamma R to immobilized immunoglobulin on the vascular endothelium, with subsequent degranulation and tissue damage. PMID:7535210

  8. Inhibitory nature of tiagabine-augmented GABAA receptor-mediated depolarizing responses in hippocampal pyramidal cells.

    Science.gov (United States)

    Jackson, M F; Esplin, B; Capek, R

    1999-03-01

    Tiagabine is a potent GABA uptake inhibitor with demonstrated anticonvulsant activity. GABA uptake inhibitors are believed to produce their anticonvulsant effects by prolonging the postsynaptic actions of GABA, released during episodes of neuronal hyperexcitability. However, tiagabine has recently been reported to facilitate the depolarizing actions of GABA in the CNS of adult rats following the stimulation of inhibitory pathways at a frequency (100 Hz) intended to mimic interneuronal activation during epileptiform activity. In the present study, we performed extracellular and whole cell recordings from CA1 pyramidal neurons in rat hippocampal slices to examine the functional consequences of tiagabine-augmented GABA-mediated depolarizing responses. Orthodromic population spikes (PSs), elicited from the stratum radiatum, were inhibited following the activation of recurrent inhibitory pathways by antidromic conditioning stimulation of the alveus, which consisted of either a single stimulus or a train of stimuli delivered at high-frequency (100 Hz, 200 ms). The inhibition of orthodromic PSs produced by high-frequency conditioning stimulation (HFS), which was always of much greater strength and duration than that produced by a single conditioning stimulus, was greatly enhanced following the bath application of tiagabine (2-100 microM). Thus, in the presence of tiagabine (20 microM), orthodromic PSs, evoked 200 and 800 ms following HFS, were inhibited to 7.8 +/- 2.6% (mean +/- SE) and 34.4 +/- 18.5% of their unconditioned amplitudes compared with only 35.4 +/- 12.7% and 98.8 +/- 12.4% in control. Whole cell recordings revealed that the bath application of tiagabine (20 microM) either caused the appearance or greatly enhanced the amplitude of GABA-mediated depolarizing responses (DR). Excitatory postsynaptic potentials (EPSPs) evoked from stratum radiatum at time points that coincided with the DR were inhibited to below the threshold for action-potential firing. Independently of the stimulus intensity with which they were evoked, the charge transferred to the soma by excitatory postsynaptic currents (EPSCs), elicited in the presence of tiagabine (20 microM) during the large (1,428 +/- 331 pA) inward currents that underlie the DRs, was decreased on the average by 90.8 +/- 1.7%. Such inhibition occurred despite the presence of the GABAB receptor antagonist, CGP 52 432 (10 microM), indicating that GABAB heteroreceptors, located on glutamatergic terminals, do not mediate the observed reduction in the amplitude of excitatory postsynaptic responses. The present results suggest that despite facilitating the induction of GABA-mediated depolarizations, tiagabine application may nevertheless increase the effectiveness of synaptic inhibition during the synchronous high-frequency activation of inhibitory interneurons by enhanced shunting.

  9. Glucocorticoid receptor mediated the propofol self-administration by dopamine D1 receptor in nucleus accumbens.

    Science.gov (United States)

    Wu, Binbin; Liang, Yuyuan; Dong, Zhanglei; Chen, Zhichuan; Zhang, Gaolong; Lin, Wenxuan; Wang, Sicong; Wang, Benfu; Ge, Ren-Shan; Lian, Qingquan

    2016-07-22

    Propofol, a widely used anesthetic, can cause addictive behaviors in both human and experimental animals. In the present study, we examined the involvement of glucocorticoid receptor (GR) signaling in the molecular process by which propofol may cause addiction. The propofol self-administration model was established by a fixed ratio 1 (FR1) schedule of reinforced dosing over successive 14days in rats. On day 15, the rats were treated with dexamethasone, a GR agonist (10-100μg/kg), or RU486, a GR antagonist (10-100μg/kg) at 1h prior to the last training. The animal behaviors were recorded automatically by the computer. The expression of dopamine D1 receptor in the nucleus accumbens (NAc) was examined by Western blot and the concentrations of plasma corticosterone were measured by enzyme-linked immunosorbent assay (ELISA). To further examine the specificity of GR in the process, mineralocorticoid receptor (MR) antagonist, spironolactone, and dexamethasone plus MR agonist, aldosterone, were also tested. Administration of dexamethasone (100μg/kg) or RU486 (⩾10mg/kg) significantly attenuated the rate of propofol maintained active nose-poke responses and infusions, which were accompanied by reductions in both plasma corticosterone level and the expression of D1 receptor in the NAc. Neither spironolactone alone nor dexamethasone combined with aldosterone affected the propofol-maintaining self-administrative behavior, indicating GR, but not MR, modulates the propofol reward in rats. In addition, neither the food-maintaining sucrose responses under FR1 schedule nor the locomotor activity was affected by any doses of dexamethasone or RU486 tested. These findings provide evidence that GR signaling may play an important role in propofol reward. PMID:27126557

  10. Sigma receptor-mediated targeted delivery of anti-angiogenic multifunctional nanodrugs for combination tumor therapy.

    Science.gov (United States)

    Li, Yuanke; Wu, Yuanyuan; Huang, Leaf; Miao, Lei; Zhou, Jianping; Satterlee, Andrew Benson; Yao, Jing

    2016-04-28

    The potential of low molecular weight heparin (LMWH) in anti-angiogenic therapy has been tempered by poor in vivo delivery to the tumor cell and potentially harmful side effects, such as the risk of bleeding due to heparin's anticoagulant activity. In order to overcome these limitations and further improve the therapeutic effect of LMWH, we designed a novel combination nanosystem of LMWH and ursolic acid (UA), which is also an angiogenesis inhibitor for tumor therapy. In this system, an amphiphilic LMWH-UA (LHU) conjugate was synthesized and self-assembled into core/shell nanodrugs with combined anti-angiogenic activity and significantly reduced anticoagulant activity. Furthermore, DSPE-PEG-AA-modified LHU nanodrugs (A-LHU) were developed to facilitate the delivery of nanodrugs to the tumor. The anti-angiogenic activity of A-LHU was investigated both in vitro and in vivo. It was found that A-LHU significantly inhibited the tubular formation of human umbilical vein endothelial cells (HUVECs) (pnanodrugs are a promising multifunctional antitumor drug delivery system. PMID:26941036

  11. Prolactin receptor-mediated internalization of imaging agents detects epithelial ovarian cancer

    Science.gov (United States)

    Sundaram, Karthik M.

    Epithelial ovarian cancer (EOC) has the highest mortality rate of all gynecologic malignant tumors. Diagnosis of epithelial ovarian cancer (EOC) presents two main challenges. The first challenge is detecting low volume (prolactin receptor (PRLR) - a cell surface tyrosine kinase receptor that is over-expressed in moderate to high levels on > 98% of epithelial ovarian cancers. Upon binding of native ligands to PRLR, the ligand:PRLR complex is internalized by cells. By conjugating gadolinium-chelates, molecules normally used as contrast agents diagnostically, to human placental lactogen (hPL), a native ligand of PRLR, we show that MRI becomes highly sensitive and specific for detecting PRLR (+) tumors in a nude mouse model of EOC. We further establish the adaptability of this approach for fluorescence-based imaging techniques using an hPL conjugated Cy5.5 dye. We conclude that molecular imaging of PRLR with hPL-conjugated imaging agents can address the current challenges that limit EOC diagnosis.

  12. Dopamine D3 Receptor Mediates Preadolescent Stress-Induced Adult Psychiatric Disorders

    OpenAIRE

    Seo, Joon H.; Kuzhikandathil, Eldo V.

    2015-01-01

    Several studies have shown that repeated stressful experiences during childhood increases the likelihood of developing depression- and anxiety-related disorders in adulthood; however, the underlying mechanisms are not well understood. We subjected drd3-EGFP and drd3-null mice to daily, two hour restraint stress episodes over a five day period during preadolescence (postnatal day 35 to 39), followed by social isolation. When these mice reached adulthood (post-natal day > 90), we assessed locom...

  13. Presynaptic CRF1 Receptors Mediate the Ethanol Enhancement of GABAergic Transmission in the Mouse Central Amygdala

    Directory of Open Access Journals (Sweden)

    Zhiguo Nie

    2009-01-01

    Full Text Available Corticotropin-releasing factor (CRF is a 41-amino-acid neuropeptide involved in stress responses initiated from several brain areas, including the amygdala formation. Research shows a strong relationship between stress, brain CRF, and excessive alcohol consumption. Behavioral studies suggest that the central amygdala (CeA is significantly involved in alcohol reward and dependence. We recently reported that the ethanol augmentation of GABAergic synaptic transmission in rat CeA involves CRF1 receptors, because both CRF and ethanol significantly enhanced the amplitude of evoked GABAergic inhibitory postsynaptic currents (IPSCs in CeA neurons from wild-type (WT and CRF2 knockout (KO mice, but not in neurons of CRF1 KO mice. The present study extends these findings using selective CRF receptor ligands, gene KO models, and miniature IPSC (mIPSC analysis to assess further a presynaptic role for the CRF receptors in mediating ethanol effects in the CeA. In whole-cell patch recordings of pharmacologically isolated GABAAergic IPSCs from slices of mouse CeA, both CRF and ethanol augmented evoked IPSCs in a concentration-dependent manner, with low EC50s. A CRF1 (but not CRF2 KO construct and the CRF1-selective nonpeptide antagonist NIH-3 (LWH-63 blocked the augmenting effect of both CRF and ethanol on evoked IPSCs. Furthermore, the new selective CRF1 agonist stressin1, but not the CRF2 agonist urocortin 3, also increased evoked IPSC amplitudes. Both CRF and ethanol decreased paired-pulse facilitation (PPF of evoked IPSCs and significantly enhanced the frequency, but not the amplitude, of spontaneous miniature GABAergic mIPSCs in CeA neurons of WT mice, suggesting a presynaptic site of action. The PPF effect of ethanol was abolished in CeA neurons of CRF1 KO mice. The CRF1 antagonist NIH-3 blocked the CRF- and ethanol-induced enhancement of mIPSC frequency in CeA neurons. These data indicate that presynaptic CRF1 receptors play a critical role in permitting or mediating ethanol enhancement of GABAergic synaptic transmission in CeA, via increased vesicular GABA release, and thus may be a rational target for the treatment of alcohol abuse and alcoholism.

  14. Inhibition of pattern recognition receptor-mediated inflammation by bioactive phytochemicals

    Science.gov (United States)

    Emerging evidence reveals that pattern-recognition receptors (PRRs), Toll-like receptors (TLRs) and Nucleotide-binding oligomerization domain proteins (NODs) mediate both infection-induced and sterile inflammation by recognizing pathogen-associated molecular patterns (PAMPs) and endogenous molecules...

  15. Cerebral ischemia enhances vascular angiotensin AT1 receptor-mediated contraction in rats

    DEFF Research Database (Denmark)

    Stenman, Emelie; Edvinsson, Lars

    2004-01-01

    BACKGROUND AND PURPOSE: The aim of the study was to examine how focal cerebral ischemia affects the expression and function of vascular angiotensin II receptors. MATERIALS AND METHODS: We used an intraluminal filament occlusion technique to occlude the right middle cerebral artery (MCA) of the rat...... with nonoccluded MCAs 48 hours after occlusion (Pcerebral ischemia in the rat upregulated the contractile....... These results support a role for AT1 receptors in cerebral ischemia, and we think that AT1 receptors might be a future therapeutic target in ischemic stroke....

  16. Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

    Directory of Open Access Journals (Sweden)

    Stephan Schmidt

    2015-05-01

    Full Text Available Many biological functions at cell level are mediated by the glycocalyx, a dense carbohydrate-presenting layer. In this layer specific interactions between carbohydrate ligands and protein receptors are formed to control cell–cell recognition, cell adhesion and related processes. The aim of this work is to shed light on the principles of complex formation between surface anchored carbohydrates and receptor surfaces by measuring the specific adhesion between surface bound mannose on a concanavalin A (ConA layer via poly(ethylene glycol-(PEG-based soft colloidal probes (SCPs. Special emphasis is on the dependence of multivalent presentation and density of carbohydrate units on specific adhesion. Consequently, we first present a synthetic strategy that allows for controlled density variation of functional groups on the PEG scaffold using unsaturated carboxylic acids (crotonic acid, acrylic acid, methacrylic acid as grafting units for mannose conjugation. We showed by a range of analytic techniques (ATR–FTIR, Raman microscopy, zeta potential and titration that this synthetic strategy allows for straightforward variation in grafting density and grafting length enabling the controlled presentation of mannose units on the PEG network. Finally we determined the specific adhesion of PEG-network-conjugated mannose units on ConA surfaces as a function of density and grafting type. Remarkably, the results indicated the absence of a molecular-level enhancement of mannose/ConA interaction due to chelate- or subsite-binding. The results seem to support the fact that weak carbohydrate interactions at mechanically flexible interfaces hardly undergo multivalent binding but are simply mediated by the high number of ligand–receptor interactions.

  17. CRTH2, a prostaglandin D2 receptor, mediates depression-related behavior in mice.

    Science.gov (United States)

    Onaka, Yusuke; Shintani, Norihito; Nakazawa, Takanobu; Haba, Ryota; Ago, Yukio; Wang, Hyper; Kanoh, Takuya; Hayata-Takano, Atsuko; Hirai, Hiroyuki; Nagata, Kin-Ya; Nakamura, Masataka; Hashimoto, Ryota; Matsuda, Toshio; Waschek, James A; Kasai, Atsushi; Nagayasu, Kazuki; Baba, Akemichi; Hashimoto, Hitoshi

    2015-05-01

    Depression is a complex neuropsychiatric disorder with an unclear molecular etiology. Inflammatory cytokines and molecular intermediates (including prostaglandins) are suggested to be involved in depression; however, the roles of prostaglandins and their respective receptors are largely unknown in depression. Using genetic and pharmacological approaches, we show here that chemoattractant receptor-homologous molecule expressed on T helper type 2 cells (CRTH2), a second receptor for prostaglandin D2 (PGD2), mediates depression-related behavior in mice. CRTH2-deficient (CRTH2(-/-)) mice showed antidepressant-like activity in a chronic corticosterone treatment-induced depression. Consistent with this observation, the pharmacological inhibition of CRTH2 via the clinically available drug ramatroban also rescued abnormal social interaction and depression-related behavior in well-established models, including chronic corticosterone-, lipopolysaccharide-, and tumor-induced pathologically relevant depression models. Importantly, chronic stress via corticosterone treatment increased mRNA levels in PGD2-producing enzymes, such as cyclooxygenase-2 and lipocalin-type PGD2 synthase, in the brain. Furthermore, the activity of the hippocampal noradrenergic system but not the dopaminergic or serotonergic systems was increased in CRTH2(-/-) mice. Together with the observation that untreated CRTH2(-/-) mice showed antidepressant-like activity in the forced swim test, these results provide evidence that central CRTH2-mediated signaling is critically involved in depression-related behavior. PMID:25698598

  18. Possible Implication of Fcγ Receptor-Mediated Trogocytosis in Susceptibility to Systemic Autoimmune Disease

    Directory of Open Access Journals (Sweden)

    Sakiko Masuda

    2013-01-01

    Full Text Available Leukocytes can “gnaw away” the plasma membrane of other cells. This phenomenon, called trogocytosis, occurs subsequent to cell-to-cell adhesion. Currently, two mechanisms of trogocytosis, adhesion molecule-mediated trogocytosis and Fcγ receptor-(FcγR- mediated trogocytosis, have been identified. In our earlier study, we established an in vitro model of FcγR-mediated trogocytosis, namely, CD8 translocation model from T cells to neutrophils. By using this model, we demonstrated that the molecules transferred to neutrophils via FcγR-mediated trogocytosis were taken into the cytoplasm immediately. This result suggests that the chance of molecules transferred via FcγR-mediated trogocytosis to play a role on the cell surface could be time-limited. Thus, we consider the physiological role of FcγR-mediated trogocytosis as a means to remove antibodies (Abs that bind with self-molecules rather than to extract molecules from other cells. This concept means that FcγR-mediated trogocytosis can be a defense mechanism to Ab-mediated autoimmune response. Moreover, the activity of FcγR-mediated trogocytosis was revealed to be parallel to the endocytotic activity of neutrophils, which was critically related to the susceptibility to systemic autoimmune diseases. The collective findings suggest that FcγR-mediated trogocytosis could physiologically play a role in removal of Abs bound to self-antigens and prevent autoimmune diseases.

  19. Endothelial 5-HT receptors mediate relaxation of porcine pulmonary arteries in response to ergotamine and dihydroergotamine.

    OpenAIRE

    Glusa, E; Roos, A. (Anna)

    1996-01-01

    1. The aim of the present study was to investigate whether antimigraine ergot compounds may act at endothelial 5-hydroxytryptamine (5-HT) receptors which trigger the release of endothelium-derived relaxing factor (EDRF). Changes in tone of porcine isolated pulmonary arteries were measured isometrically. The integrity of the endothelium was assessed by the bradykinin-induced relaxation of prostaglandin F2 alpha (PGF2 alpha, 3 microM)-precontracted vessels. 2. The ergot derivatives ergotamine, ...

  20. Characterization of putative 5-HT7 receptors mediating tachycardia in the cat

    OpenAIRE

    Villalón, Carlos; Heiligers, Jan; Centurion, David; De Vries, Peter; Saxena, Pramod Ranjan

    1997-01-01

    It has been suggested that the tachycardic response to 5-hydroxytryptamine (5-HT) in the spinal-transected cat is mediated by ‘5-HT1-like' receptors since this effect, being mimicked by 5-carboxamidotryptamine (5-CT), is not modified by ketanserin or MDL 72222, but it is blocked by methiothepin, methysergide or mesulergine. The present study was set out to reanalyse this suggestion in terms of the IUPHAR 5-HT receptor classification schemes proposed in 1994 and 1996.Intravenous (i.v.) bolus i...

  1. Accumbens Shell AMPA Receptors Mediate Expression of Extinguished Reward Seeking through Interactions with Basolateral Amygdala

    Science.gov (United States)

    Millan, E. Zayra; McNally, Gavan P.

    2011-01-01

    Extinction is the reduction in drug seeking when the contingency between drug seeking behavior and the delivery of drug reward is broken. Here, we investigated a role for the nucleus accumbens shell (AcbSh). Rats were trained to respond for 4% (v/v) alcoholic beer in one context (Context A) followed by extinction in a second context (Context B).…

  2. Food Restriction Increases Glutamate Receptor-Mediated Burst Firing of Dopamine Neurons

    OpenAIRE

    Branch, Sarah Y.; Goertz, R. Brandon; Sharpe, Amanda L.; Pierce, Janie; Roy, Sudip; Ko, Daijin; Paladini, Carlos A; Beckstead, Michael J.

    2013-01-01

    Restriction of food intake increases the acquisition of drug abuse behavior and enhances the reinforcing efficacy of those drugs. However, the neurophysiological mechanisms responsible for the interactions between feeding state and drug use are largely unknown. Here we show that chronic mild food restriction increases the burst firing of dopamine neurons in the substantia nigra. Dopamine neurons from food-restricted mice exhibited increased burst firing in vivo, an effect that was enhanced by...

  3. Inhibitory effect of tetramethylpyrazine on P2X receptor-mediated excitation of nociceptive afferents

    Institute of Scientific and Technical Information of China (English)

    Shang-DongLiang; YunGao; Bao-HuaXu; Song-NiuMu; Chang-ShuiXu

    2004-01-01

    Object: In this study we investigated the effects of intrathecally administered TMP on the acute nociception mediated by the local administration of P2X receptor agonists ( ATP or α,β-meATP) or formalin in mouse hindpaw and the effects of TMP on the current evoked by P2X receptor agonists ( ATP or α, β-meATP) in rat DRG neurons using the whole cell

  4. Coated vesicles participate in the receptor-mediated endocytosis of insulin

    OpenAIRE

    1983-01-01

    We have purified coated vesicles from rat liver by differential ultracentrifugation. Electron micrographs of these preparations reveal only the polyhedral structures typical of coated vesicles. SDS PAGE of the coated vesicle preparation followed by Coomassie Blue staining of proteins reveals a protein composition also typical of coated vesicles. We determined that these rat liver coated vesicles possess a latent insulin binding capability. That is, little if any specific binding of 125I-insul...

  5. Role of coated vesicles, microfilaments, and calmodulin in receptor- mediated endocytosis by cultured B lymphoblastoid cells

    OpenAIRE

    1980-01-01

    Cell surface receptor IgM molecules of cultured human lymlphoblastoid cells (WiL2) patch and redistribute into a cap over the Golgi region of the cell after treatment with multivalent anti-IgM antibodies. During and after the redistribution, ligand-receptor clusters are endocytosed into coated pits and coated vesicles. Morphometric analysis of the distribution of ferritin-labeled ligand at EM resolution reveals the following sequence of events in the endocytosis of cell surface IgM: (a) bindi...

  6. Trafficking of α1B-adrenergic receptor mediated by inverse agonist in living cells

    Institute of Scientific and Technical Information of China (English)

    MingXU; Ying-huaGUAN; NingXU; Zhang-yiLIANG; Shu-yiWang; YaoSONG; Chi-deHAN; Xin-shengZHAO; You-yiZHANG

    2005-01-01

    AIM The project is aimed at understanding the action of inverse agonist at single molecule level and capturing the real time picture of molecular behavior of α1B-adrenergic receptor (AR) mediated by inverse agonist in living cells by single molecule detection (SMD). METHODS The location and distribution of α1B-AR was detected by laser confocal and whole cell 3H-prazosin binding assay. Dynamic imaging of BODIPY-FL-labeled prazosin (Praz), specific antagonist of (1-AR, was observed in α1B-AR stably expressed human embryonic kidney 293 (HEK293) living cells. The detection of real-time dynamic behaviors of AR was achieved by using fluorescence-labeled AR and its ligand combined with SMD techniques. RESULTS α1B-AR was predominantly distributed on the cell surface and 8.2% of the total receptors were located in cytosol.

  7. Plant Growth Regulators.

    Science.gov (United States)

    Nickell, Louis G.

    1978-01-01

    Describes the effect of "plant growth regulators" on plants, such as controlling the flowering, fruit development, plant size, and increasing crop yields. Provides a list of plant growth regulators which includes their chemical, common, and trade names, as well as their different use(s). (GA)

  8. Mortgage market regulation: Europe

    NARCIS (Netherlands)

    M.B. Aalbers

    2012-01-01

    Despite several European Union (EU) initiatives, there is only limited pan-European mortgage market regulation. The EU strategy can be characterised as one of parallel liberalisation and consolidation. This article highlights the key differences in regulation among European mortgage markets. Mortgag

  9. Emotion-regulation choice

    NARCIS (Netherlands)

    Sheppes, Gal; Scheibe, Susanne; Suri, Gaurav; Gross, James J.

    2011-01-01

    Despite centuries of speculation about how to manage negative emotions, little is actually known about which emotion-regulation strategies people choose to use when confronted with negative situations of varying intensity. On the basis of a new process conception of emotion regulation, we hypothesiz

  10. SorCS2 Regulates Dopaminergic Wiring and Is Processed into an Apoptotic Two-Chain Receptor in Peripheral Glia

    DEFF Research Database (Denmark)

    Glerup, Simon; Olsen, Ditte; Vægter, Christian Bjerggaard;

    2014-01-01

    Balancing trophic and apoptotic cues is critical for development and regeneration of neuronal circuits. Here we identify SorCS2 as a proneurotrophin (proNT) receptor, mediating both trophic and apoptotic signals in conjunction with p75NTR. CNS neurons, but not glia, express SorCS2 as a single-cha...

  11. Benchmarking and Regulation

    DEFF Research Database (Denmark)

    Agrell, Per J.; Bogetoft, Peter

    nchmarking methods, and in particular Data Envelopment Analysis (DEA), have become well-established and informative tools for economic regulation. DEA is now routinely used by European regulators to set reasonable revenue caps for energy transmission and distribution system operators. The applica......nchmarking methods, and in particular Data Envelopment Analysis (DEA), have become well-established and informative tools for economic regulation. DEA is now routinely used by European regulators to set reasonable revenue caps for energy transmission and distribution system operators....... The application of benchmarking in regulation, however, requires specific steps in terms of data validation, model specification and outlier detection that are not systematically documented in open publications, leading to discussions about regulatory stability and economic feasibility of these techniques...

  12. Iloprost- and isoproterenol-induced increases in cAMP are regulated by different phosphodiesterases in erythrocytes of both rabbits and humans.

    Science.gov (United States)

    Adderley, Shaquria P; Dufaux, Eileen A; Sridharan, Meera; Bowles, Elizabeth A; Hanson, Madelyn S; Stephenson, Alan H; Ellsworth, Mary L; Sprague, Randy S

    2009-05-01

    Activation of the G protein G(s) results in increases in cAMP, a necessary step in the pathway for ATP release from rabbit and human erythrocytes. In all cells, the level of cAMP is the product of its synthesis by adenylyl cyclase and its hydrolysis by phosphodiesterases (PDEs). Both iloprost (Ilo), a PGI(2) analog, and isoproterenol (Iso), a beta-agonist, stimulate receptor-mediated increases in cAMP in rabbit and human erythrocytes. However, the specific PDEs associated with each of these signaling pathways in the erythrocyte have not been fully characterized. Previously, we reported that PDE3B is present in rabbit and human erythrocyte membranes and that PDE3 inhibitors potentiate Ilo-induced increases in cAMP. Here we report that inhibitors of either PDE2 or PDE4, erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) and rolipram, respectively, potentiate Iso-induced increases in cAMP in rabbit and human erythrocytes. Importantly, these inhibitors had no effect on cAMP increases associated with the incubation of erythrocytes with Ilo. In addition, we establish, for the first time, the presence of PDE2A protein in rabbit and human erythrocyte membranes. Finally, we determined that preincubation of human erythrocytes with EHNA and rolipram together potentiate Iso-induced ATP release, whereas preincubation with cilostazol enhances Ilo-induced release of ATP. These results are consistent with the hypothesis that, in rabbit and human erythrocytes, Ilo-induced increases in cAMP and ATP release are regulated by PDE3, whereas those associated with Iso are regulated by the activities of both PDE2 and PDE4. These studies demonstrate that PDE activity in these cells is localized to specific signaling pathways. PMID:19252089

  13. Regulation of megakaryocytopoiesis.

    Science.gov (United States)

    Caen, J P; Han, Z C; Bellucci, S; Alemany, M

    1999-09-01

    After 35 years of research, a physiological regulator of platelet production has been identified and the recombinant protein is available. With the discovery of thrombopoietin (TPO), its potential use in a wide variety of clinical megakaryocytic and platelet disorders has been expected and clinical trials have been undertaken. To date, the reported encouraging pre-clinical studies indicate that, as with erythropoietin or G-CSF, minimal toxicity can be expected. A potential limiting side-effect of TPO could be the induction of thrombosis. Nevertheless, it is too early to know whether this cytokine will be of major therapeutic importance for patients with life-threatening thrombocytopenia, such as patients undergoing bone marrow transplantation or subjected to a high dose of chemotherapy. Several experimental and clinical studies are still needed to determine the efficacy of TPO in the prevention or the amelioration of bleeding, which is the ultimate goal for the appropriate use of cytokines with haemostatic benefit. Basic and clinical studies on regulators of megakaryocytopoiesis have rapidly progressed. Now, there is no doubt that some of these regulators are effective in correcting haematopoietic disorders of various aetiologies. Studies on negative regulators not only are important to understand the regulation of megakaryocytopoiesis in normal and pathological states but also have a potential clinical application. Some of these regulators have been shown to be effective in the treatment of essential thrombocythaemia and other myeloproliferative disorders. Platelet factor 4 (PF4) and some other chemokines are also capable of protecting progenitor cells from the cytotoxicity of chemotherapeutic drugs. However, detailed investigations are still required to determine the precise mechanism(s) of action of these regulators and to establish the optimal clinical protocols of negative regulators alone or in association with positive regulators for the treatment of various

  14. Electrical installations and regulations

    CERN Document Server

    Whitfield, J F

    1966-01-01

    Electrical Installations and Regulations focuses on the regulations that apply to electrical installations and the reasons for them. Topics covered range from electrical science to alternating and direct current supplies, as well as equipment for providing protection against excess current. Cables, wiring systems, and final subcircuits are also considered, along with earthing, discharge lighting, and testing and inspection.Comprised of 12 chapters, this book begins with an overview of electrical installation work, traits of a good electrician, and the regulations governing installations. The r

  15. The power of regulation

    International Nuclear Information System (INIS)

    Slides accompanying a presentation at The Power of Change Conference in Vancouver, BC in April 1995 about regulations affecting the power industry were presented. Issues addressed included customer choice, incentive regulation changes (price-caps, revenue sharing and pricing flexibility), the reactions of Canadian industry to regulatory changes, and anticipated reactions of the financial markets to changes in regulations. The potential effects of competition and changes that will create competition were discussed. The level of readiness of Canadian financial, ownership and regulatory bodies was discussed. The needs and expectations of investors from a new regulatory regime were quesstimated. Possible alternatives to the present regulatory framework were suggested

  16. Sport Fishing Regulations

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The regulations for sport fishing on St. Vincent National Wildlife Refuge are outlined in this document. Fishing is only permitted from sunrise to sunset, and only...

  17. Regulating deregulated energy markets

    International Nuclear Information System (INIS)

    The North American gas and electricity markets are fast evolving, and regulators are currently faced with a host of issues such as market-based rates, unbundling, stranded costs, open access, and incentive regulation are surfacing as a result of deregulation. The regulatory environment in Ontario was reviewed by the author. Deregulated markets rule, from commodities to gas and electricity. Additionally, there is an evolution of traditional utility regulation. A look at deregulated markets revealed that there are regulations on boundary conditions on the deregulated market. Under the Ontario Energy Board (OEB), all generators, transmitters, distributors, and retailers of electricity must be licensed. The standard supply service (SSS) offered by electricity distributors and system gas which is still being sold by natural gas distributors continues to be regulated by OEB. One issue that was addressed was separation for revenues and costs of the utility's purchase and sale of gas business, at least for accounting purposes. The next issue discussed was cost of system gas and SSS, followed by timely signals and prudent incurred costs. Historical benefits were reviewed, such as historical commitments to low-cost electricity. Pooling transportation costs, transmission pricing continued, market-based rates, unbundling, stranded costs, open access, incentive regulation/ performance based regulation (PBR) were all discussed. Price cap on PBR, both partial and comprehensive were looked at. A requirement to review guidelines on cost of capital and an application to extend blanket approval provisions for gas storage were discussed, as they are amongst some of the challenges of the future. Other challenges include revised rules and practice and procedure; practice directions for cost awards, appeals, and other functions; confidentiality guidelines; and refinements to the role of and approaches to alternative dispute resolution. The future role of regulators was examined in light

  18. Optimal Regulation of Auditing

    OpenAIRE

    Pagano, Marco; Immordino, Giovanni

    2007-01-01

    We study regulation of the auditing profession in a model where audit quality is unobservable and enforcing regulation is costly. The optimal audit standard falls short of the first-best audit quality, and is increasing in the riskiness of firms and in the amount of funding they seek. The model can encompass collusion between clients and auditors, arising from the joint provision of auditing and consulting services: deflecting collusion requires less ambitious standards. Finally, banning the ...

  19. Financial Regulation Going Forward

    OpenAIRE

    Franklin Allen; Elena Carletti

    2010-01-01

    The financial sector is heavily regulated in order to prevent financial crises. The recent crisis showed how ineffective this regulation and other types of government intervention were in achieving this aim. We argue that the crisis was primarily caused by housing price bubbles. These occurred because of too loose monetary policies and the easy availability of credit resulting from the build up of large foreign exchange reserves by Asian central banks. A number of regulatory reforms are sugge...

  20. FLIP the Switch: Regulation of Apoptosis and Necroptosis by cFLIP

    OpenAIRE

    Yuichi Tsuchiya; Osamu Nakabayashi; Hiroyasu Nakano

    2015-01-01

    cFLIP (cellular FLICE-like inhibitory protein) is structurally related to caspase-8 but lacks proteolytic activity due to multiple amino acid substitutions of catalytically important residues. cFLIP protein is evolutionarily conserved and expressed as three functionally different isoforms in humans (cFLIPL, cFLIPS, and cFLIPR). cFLIP controls not only the classical death receptor-mediated extrinsic apoptosis pathway, but also the non-conventional pattern recognition receptor-dependent apoptot...

  1. Regulating energy industries

    International Nuclear Information System (INIS)

    The concept of sector-based regulation takes on significant importance in the context of market liberalization. The overall aim is to conciliate, in the considered sector, fair competition with the achievement of public service missions. However, the nature of the authority in charge of this regulation is not prone to harmonized clauses, even in Europe. For electricity for example, the 96/92/CE directive of 19 December 1996 concerning common rules for the inner electricity market, does not state this and Germany, which has not designed any sector-based regulator, applies the general procedure of litigation settlement by the equivalent of the competition Council. In France, the law Nr 2000-108 of 10 February 2000 defines the CRE (Electricity Regulation Commission) is article 28 as including six members, three of which are appointed by Government and the three others respectively by each of the presidents of the parliamentary assemblies. Many other countries have made the same choice. However, the scope of the missions given to these specialized authorities varies considerably according to the country. At European level, what are the different models of organisation of sector-based regulation in the energy field? How are the new regulators organised in relation with the competition authorities? Will the new models converge on the medium term or on the long term? Must we anticipate the creation of European regulation authorities to rule the problems concerning several national markets? What can we learn from the recent electricity crisis in California? To try and answer these questions, Mr Michel Matheu presented a European comparative study and before the debate started, Mr Pierre Couveinhes suggested a reflection on the practical implications of the analyses carried out. (authors)

  2. Nuclear regulation in transition

    International Nuclear Information System (INIS)

    The current state of nuclear regulations in the USA is examined. Since Three Mile Island the regulation of the nuclear power industry has been undergoing a noticeable transition. It will be argued here that the transition is characterized by two indicia. First, the primary focus of state and federal regulators has been on the financial aspects of the industry: this is best seen in the context of decisions allocating the costs of nuclear plant cancellations. Second, decisionmaking power has been decentralized: although the regulatory history of nuclear power demonstrates the tradition of centralized decisionmaking power (i.e., formerly the primary decisionmaking body was the Atomic Energy Commission), now States share decisionmaking power with the Nuclear Regulatory Commission. In Section 1 a brief legislative history of nuclear regulation is presented to establish the assertion that nuclear regulation, both de jure and de facto, was centralized. Next, Section 2 canvasses recent United States Supreme Court opinions regarding nuclear regulation. The Court frequently acts as policymaker through the consequences of its opinions, if not by its intent. In the area of nuclear policymaking, the Court has paid allegiance recently both to the tradition of centralization and to the movement toward decentralization. This dualism is reflected in other federal court decisions as well which will be briefly mentioned. Continuing the analysis of Federal regulation, Section 3 examines the current reform efforts of the NRC. Section 4 presents an examination of State responses to nuclear plant cancellations. In this section, State administrative agency and court decisions will be examined and recent State legislation will be discussed. (author)

  3. Worldwide regulations for mycotoxins.

    Science.gov (United States)

    van Egmond, Hans P

    2002-01-01

    Since the discovery of the aflatoxins in the 1960s, regulations have been established in many countries to protect the consumer from the harmful effects of mycotoxins that may contaminate foodstuffs. Various factors play a role in the decision-making process of setting limits for mycotoxins. These include scientific factors such as the availability of toxicological data, survey data, knowledge about the distribution of mycotoxins in commodities, and analytical methodology. Economical and political factors such as commercial interests and sufficiency of food supply have their impact as well. International enquiry's on existing mycotoxin legislation in foodstuffs and animal feedstuffs have been carried out several times in the 1980s and 1990s and details about tolerances, legal basis, responsible authorities, official protocols of analysis and sampling have been published. Recently a comprehensive update on worldwide regulations was published as FAO Food and Nutrition Paper 64. It appeared that at least 77 countries now have specific regulations for mycotoxins, 13 countries are known to have no specific regulations, whereas no data are available for about 50 countries, many of them in Africa. Over the years, a large diversity in tolerance levels for mycotoxins has remained. Some free trade zones (EU, MERCOSUR) are in the process of harmonizing the limits and regulations for mycotoxins in their respective member states, but it is not likely that worldwide harmonized limits for mycotoxins will soon be within reach.

  4. Radiation emitting devices regulations

    International Nuclear Information System (INIS)

    The Radiation Emitting Devices Regulations are the regulations referred to in the Radiation Emitting Devices Act and relate to the operation of devices. They include standards of design and construction, standards of functioning, warning symbol specifications in addition to information relating to the seizure and detention of machines failing to comply with the regulations. The radiation emitting devices consist of the following: television receivers, extra-oral dental x-ray equipment, microwave ovens, baggage inspection x-ray devices, demonstration--type gas discharge devices, photofluorographic x-ray equipment, laser scanners, demonstration lasers, low energy electron microscopes, high intensity mercury vapour discharge lamps, sunlamps, diagnostic x-ray equipment, ultrasound therapy devices, x-ray diffraction equipment, cabinet x-ray equipment and therapeutic x-ray equipment

  5. ANTICIPATING AND REGULATING BIOSYSTEM

    Directory of Open Access Journals (Sweden)

    Ion Iorga Siman

    2010-06-01

    Full Text Available Regulating biosystems closely related to human beings are structures still difficult to understand.Numerous intimate processes taking place in these systems, even their actual constitution, are insufficiently decoded, and that they have populated the world long before man invented the first regulator, appears not to have contributed much to their knowledge. This work is intended to highlight what regulating biosystems are.There is no secret that somatic muscles perform control operations which no act of moving would be possible without. All actions are the result of dynamic controlled processes adjusted to strict control laws. By treating them very seriously may lead to knowledge of processes occurring in complex systems

  6. Staff rules and regulations

    CERN Document Server

    HR Department

    2007-01-01

    The 11th edition of the Staff Rules and Regulations, dated 1 January 2007, adopted by the Council and the Finance Committee in December 2006, is currently being distributed to departmental secretariats. The Staff Rules and Regulations, together with a summary of the main modifications made, will be available, as from next week, on the Human Resources Department's intranet site: http://cern.ch/hr-web/internal/admin_services/rules/default.asp The main changes made to the Staff Rules and Regulations stem from the five-yearly review of employment conditions of members of the personnel. The changes notably relate to: the categories of members of the personnel (e.g. removal of the local staff category); the careers structure and the merit recognition system; the non-residence, installation and re-installation allowances; the definition of family, family allowances and family-related leave; recognition of partnerships; education fees. The administrative circulars, some of which are being revised following the ...

  7. Environmentally regulated aerospace coatings

    Science.gov (United States)

    Morris, Virginia L.

    1995-01-01

    Aerospace coatings represent a complex technology which must meet stringent performance requirements in the protection of aerospace vehicles. Topcoats and primers are used, primarily, to protect the structural elements of the air vehicle from exposure to and subsequent degradation by environmental elements. There are also many coatings which perform special functions, i.e., chafing resistance, rain erosion resistance, radiation and electric effects, fuel tank coatings, maskants, wire and fastener coatings. The scheduled promulgation of federal environmental regulations for aerospace manufacture and rework materials and processes will regulate the emissions of photochemically reactive precursors to smog and air toxics. Aerospace organizations will be required to identify, qualify and implement less polluting materials. The elimination of ozone depleting chemicals (ODC's) and implementation of pollution prevention requirements are added constraints which must be addressed concurrently. The broad categories of operations affected are the manufacture, operation, maintenance, and repair of military, commercial, general aviation, and space vehicles. The federal aerospace regulations were developed around the precept that technology had to be available to support the reduction of organic and air toxic emissions, i.e., the regulations cannot be technology forcing. In many cases, the regulations which are currently in effect in the South Coast Air Quality Management District (SCAQMD), located in Southern California, were used as the baseline for the federal regulations. This paper addresses strategies used by Southern California aerospace organizations to cope with these regulatory impacts on aerospace productions programs. All of these regulatory changes are scheduled for implementation in 1993 and 1994, with varying compliance dates established.

  8. Regulation as Rhetoric

    DEFF Research Database (Denmark)

    Boll, Karen; Györy, Csaba

    This paper analyses the way regulatory agencies strategically use public ‘rhetoric’ and ‘management of appearance’ to strengthen their regulation. It reports a comparative study of the Securities and Exchange Commission (SEC) which is the US federal securities regulator and the Danish Tax and...... environment, these two agencies apply strategies that appear to be strikingly similar, and these similarities are worth investigating not despite, but exactly because of the differing political and social environment. We track recent shifts in organizational practice at these two agencies and argue that both...

  9. Nuclear regulations and environment

    International Nuclear Information System (INIS)

    After an historical overview of the nuclear regulation system in Argentina a description is made of the country's Nuclear Regulatory Authority (ARN) and of its regulation and control functions. Its organic structure is also outlined. A detailed report is given of the environmental monitoring activities in the sites of the operating Argentine nuclear power plants as well as those of the nuclear research centres. A special reference is made of the monitoring of the relevant uranium mining districts in Argentina. The radon determination in houses of several regions of the country is also mentioned

  10. Regulated underground storage tanks

    International Nuclear Information System (INIS)

    This guidance package is designed to assist DOE Field operations by providing thorough guidance on the underground storage tank (UST) regulations. [40 CFR 280]. The guidance uses tables, flowcharts, and checklists to provide a ''roadmap'' for DOE staff who are responsible for supervising UST operations. This package is tailored to address the issues facing DOE facilities. DOE staff should use this guidance as: An overview of the regulations for UST installation and operation; a comprehensive step-by-step guidance for the process of owning and operating an UST, from installation to closure; and a quick, ready-reference guide for any specific topic concerning UST ownership or operation

  11. Volume Regulation in Epithelia

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Hoffmann, Else Kay

    2016-01-01

    We review studies on regulatory volume decrease (RVD) and regulatory volume increase (RVI) of major ion and water transporting vertebrate epithelia. The rate of RVD and RVI is faster in cells of high osmotic permeability like amphibian gallbladder and mammalian proximal tubule as compared...... to amphibian skin and mammalian cortical collecting tubule of low and intermediate osmotic permeability. Crosstalk between entrance and exit mechanisms interferes with volume regulation both at aniso-osmotic and iso-osmotic volume perturbations. It has been proposed that cell volume regulation is an intrinsic...

  12. Cyberplagiarism in University Regulations

    Directory of Open Access Journals (Sweden)

    Santiago Cavanillas

    2008-12-01

    Full Text Available The article examines the legal framework for plagiarism, and its twofold nature of illicit appropriation (from the author of the plagiarized work and fraud (with regard to the target audience of the plagiarism. Based on these premises, academic cyberplagiarism is analysed as a form of plagiarism carried out using electronic tools in the university setting. The question of responsibility (who can regulate the legal consequences of plagiarism? before and after the Ley Orgánica de Universidades (organic law on universities, LOU is studied, as is the disciplinary handling of cyberplagiarism with the limited regulations currently in place at universities.

  13. Regulation, Competition, and Information

    OpenAIRE

    Mian Muhammad Javed

    2002-01-01

    You know it is very hard after the Governor, State Bank, to make a presentation but I will try to do it in a very mundane way. You know the Regulatory Bodies specially in the Economic Sector in recent times. There has been a sort of resurgence, leaving aside the regulation of the financial sector, which has been doing very well. Our old memory of regulation is not so pleasant. Long ago, there used to be a transport Authority which used to dole out “Route Permits” as political favours, and the...

  14. The Impact of Regulating Social Science Research with Biomedical Regulations

    Science.gov (United States)

    Durosinmi, Brenda Braxton

    2011-01-01

    The Impact of Regulating Social Science Research with Biomedical Regulations Since 1974 Federal regulations have governed the use of human subjects in biomedical and social science research. The regulations are known as the Federal Policy for the Protection of Human Subjects, and often referred to as the "Common Rule" because 18 Federal…

  15. NMDA receptors regulate nicotine-enhanced brain reward function and intravenous nicotine self-administration: role of the ventral tegmental area and central nucleus of the amygdala.

    Science.gov (United States)

    Kenny, Paul J; Chartoff, Elena; Roberto, Marisa; Carlezon, William A; Markou, Athina

    2009-01-01

    Nicotine is considered an important component of tobacco responsible for the smoking habit in humans. Nicotine increases glutamate-mediated transmission throughout brain reward circuitries. This action of nicotine could potentially contribute to its intrinsic rewarding and reward-enhancing properties, which motivate consumption of the drug. Here we show that the competitive N-methyl-D-aspartate (NMDA) receptor antagonist LY235959 (0.5-2.5 mg per kg) abolished nicotine-enhanced brain reward function, reflected in blockade of the lowering of intracranial self-stimulation (ICSS) thresholds usually observed after experimenter-administered (0.25 mg per kg) or intravenously self-administered (0.03 mg per kg per infusion) nicotine injections. The highest LY235959 dose (5 mg per kg) tested reversed the hedonic valence of nicotine from positive to negative, reflected in nicotine-induced elevations of ICSS thresholds. LY235959 doses that reversed nicotine-induced lowering of ICSS thresholds also markedly decreased nicotine self-administration without altering responding for food reinforcement, whereas the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor antagonist NBQX had no effects on nicotine intake. In addition, nicotine self-administration upregulated NMDA receptor subunit expression in the central nucleus of the amygdala (CeA) and ventral tegmental area (VTA), suggesting important interactions between nicotine and the NMDA receptor. Furthermore, nicotine (1 microM) increased NMDA receptor-mediated excitatory postsynaptic currents in rat CeA slices, similar to its previously described effects in the VTA. Finally, infusion of LY235959 (0.1-10 ng per side) into the CeA or VTA decreased nicotine self-administration. Taken together, these data suggest that NMDA receptors, including those in the CeA and VTA, gate the magnitude and valence of the effects of nicotine on brain reward systems, thereby regulating motivation to consume the drug.

  16. Nuclear safety regulations

    International Nuclear Information System (INIS)

    The Departmental Rules and The Safety Guides were issued by the NNSA in 1998. The NNSA performed the activities of propagation and implementation of nuclear safety regulations at QTNPP in order to improve the nuclear safety culture of operating organization and construct and contract organizations

  17. Situated bio-regulation

    DEFF Research Database (Denmark)

    Prainsack, Barbara; Wahlberg, Ayo

    2013-01-01

    Several years ago, both authors engaged in research into bioscience and biomedical regulation in Asian countries. One of us (BP) explored why the regulatory and discursive embedding of human embryonic stem cell in Israel was much more permissive than elsewhere. The other author (AW) sought to und...

  18. Regulating the Internet

    Science.gov (United States)

    Anderson, Byron

    2007-01-01

    The Internet's breakthrough to primetime usage beginning in the mid-1990s evolved in an era of openness. Unfettered access seemed key to Internet development. An important foundation for the 1996 Telecommunications Act was the theory that the telecom industry would work best if it were free of government regulation, a guiding principle that has…

  19. Regulating multiple externalities

    DEFF Research Database (Denmark)

    Waldo, Staffan; Jensen, Frank; Nielsen, Max;

    2016-01-01

    instruments. However, solving the open-access externality problem also affects CO2 emissions. By using a bio-economic model covering Iceland, Norway, Denmark, Sweden, and the Faroe Islands, it is shown that regulations of the open-access externality problem have a large effect on both economic performance...

  20. Jordan Corporate Governance Regulations

    OpenAIRE

    Jordan Institute of Directors

    2013-01-01

    As the importance of Corporate Governance increases, an awareness and understanding of the different relevant regulations becomes of paramount value. The importance and value of Corporate Governance is not the core of this publication. The publication is built around the premise that Corporate Governance is important and increasingly becoming of significant importance for growth, continued...

  1. Reconceptualizing Civil Regulation

    DEFF Research Database (Denmark)

    Galang, Roberto Martin; Castello, Itziar

    2011-01-01

    and environmental standards; but also that local, small and medium companies play a key role in the development of Asian civil regulation. We call this second finding the “CSR importation trap”. Our findings are supported by evidence on the limitations in the interchangeable properties of business and governments...

  2. Legislation and regulation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-09-01

    This document presents the fulfilling of the Brazilian obligations under the Convention on Nuclear Safety. The Chapter 3 of the document contains some details about the Brazilian legislation and regulation, the legislative and regulatory framework, regulatory body and responsibility of the license holder.

  3. Vehicle recycling regulations

    DEFF Research Database (Denmark)

    Smink, Carla

    2007-01-01

    The number of end-of-life vehicles (ELVs) in the EU is increasing continously. Around 75 percent of an ELV are recyclable metals. The forecast growth in the number of ELVs calls for regulation that aims to minimise the environmental impact of a car. Using Denmark as an example, this article...

  4. Volume Regulated Channels

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjær

    expressed ICl, swell will decrease proliferation in several cell types, including Ehrlich cells. A differentiated expression of ICl, swell in the cell cycle has been described in different cell types indicating a regulating role. In Ehrlich Lettré ascites (ELA) cells we suggest the differentiated expression...

  5. Regulation of cholesterol homeostasis

    NARCIS (Netherlands)

    van der Wulp, Mariette Y. M.; Verkade, Henkjan J.; Groen, Albert K.

    2013-01-01

    Hypercholesterolemia is an important risk factor for cardiovascular disease. It is caused by a disturbed balance between cholesterol secretion into the blood versus uptake. The pathways involved are regulated via a complex interplay of enzymes, transport proteins, transcription factors and non-codin

  6. International telecommunications market regulation

    OpenAIRE

    Productivity Commission

    2001-01-01

    On 23 February 1999 the Assistant Treasurer referred international telecommunic-ations market regulation for inquiry and report within six months. The report focused on the reform of international telecommunications markets, in particular on the payment arrangements between providers of international telecommunications services.

  7. Regulation of Energy Balance.

    Science.gov (United States)

    Bray, George A.

    1985-01-01

    Explains relationships between energy intake and expenditure focusing on the cellular, chemical and neural mechanisms involved in regulation of energy balance. Information is referenced specifically to conditions of obesity. (Physicians may earn continuing education credit by completing an appended test). (ML)

  8. Regulating the private security industry

    CERN Document Server

    Percy, Sarah

    2002-01-01

    The under-regulation of the private security industry has increasingly become a topic of media and academic interest. This Adelphi Paper enters the debate by explaining why the industry requires further regulation, and what is wrong with the current system. It begins by briefly defining the industry and explaining the need for more effective regulation, before analysing three types of regulation: domestic, international and informal (including self-regulation).

  9. Molecular conservation of estrogen-response associated with cell cycle regulation, hormonal carcinogenesis and cancer in zebrafish and human cancer cell lines

    Directory of Open Access Journals (Sweden)

    Govindarajan Kunde R

    2011-05-01

    Full Text Available Abstract Background The zebrafish is recognized as a versatile cancer and drug screening model. However, it is not known whether the estrogen-responsive genes and signaling pathways that are involved in estrogen-dependent carcinogenesis and human cancer are operating in zebrafish. In order to determine the potential of zebrafish model for estrogen-related cancer research, we investigated the molecular conservation of estrogen responses operating in both zebrafish and human cancer cell lines. Methods Microarray experiment was performed on zebrafish exposed to estrogen (17β-estradiol; a classified carcinogen and an anti-estrogen (ICI 182,780. Zebrafish estrogen-responsive genes sensitive to both estrogen and anti-estrogen were identified and validated using real-time PCR. Human homolog mapping and knowledge-based data mining were performed on zebrafish estrogen responsive genes followed by estrogen receptor binding site analysis and comparative transcriptome analysis with estrogen-responsive human cancer cell lines (MCF7, T47D and Ishikawa. Results Our transcriptome analysis captured multiple estrogen-responsive genes and signaling pathways that increased cell proliferation, promoted DNA damage and genome instability, and decreased tumor suppressing effects, suggesting a common mechanism for estrogen-induced carcinogenesis. Comparative analysis revealed a core set of conserved estrogen-responsive genes that demonstrate enrichment of estrogen receptor binding sites and cell cycle signaling pathways. Knowledge-based and network analysis led us to propose that the mechanism involving estrogen-activated estrogen receptor mediated down-regulation of human homolog HES1 followed by up-regulation cell cycle-related genes (human homologs E2F4, CDK2, CCNA, CCNB, CCNE, is highly conserved, and this mechanism may involve novel crosstalk with basal AHR. We also identified mitotic roles of polo-like kinase as a conserved signaling pathway with multiple entry

  10. Regulator of G-protein signalling and GoLoco proteins suppress TRPC4 channel function via acting at Gαi/o.

    Science.gov (United States)

    Jeon, Jae-Pyo; Thakur, Dhananjay P; Tian, Jin-Bin; So, Insuk; Zhu, Michael X

    2016-05-15

    Transient receptor potential canonical 4 (TRPC4) forms non-selective cation channels implicated in the regulation of diverse physiological functions. Previously, TRPC4 was shown to be activated by the Gi/o subgroup of heterotrimeric G-proteins involving Gαi/o, rather than Gβγ, subunits. Because the lifetime and availability of Gα-GTP are regulated by regulators of G-protein signalling (RGS) and Gαi/o-Loco (GoLoco) domain-containing proteins via their GTPase-activating protein (GAP) and guanine-nucleotide-dissociation inhibitor (GDI) functions respectively, we tested how RGS and GoLoco domain proteins affect TRPC4 currents activated via Gi/o-coupled receptors. Using whole-cell patch-clamp recordings, we show that both RGS and GoLoco proteins [RGS4, RGS6, RGS12, RGS14, LGN or activator of G-protein signalling 3 (AGS3)] suppress receptor-mediated TRPC4 activation without causing detectable basal current or altering surface expression of the channel protein. The inhibitory effects are dependent on the GAP and GoLoco domains and facilitated by enhancing membrane targeting of the GoLoco protein AGS3. In addition, RGS, but not GoLoco, proteins accelerate desensitization of receptor-activation evoked TRPC4 currents. The inhibitory effects of RGS and GoLoco domains are additive and are most prominent with RGS12 and RGS14, which contain both RGS and GoLoco domains. Our data support the notion that the Gα, but not Gβγ, arm of the Gi/o signalling is involved in TRPC4 activation and unveil new roles for RGS and GoLoco domain proteins in fine-tuning TRPC4 activities. The versatile and diverse functions of RGS and GoLoco proteins in regulating G-protein signalling may underlie the complexity of receptor-operated TRPC4 activation in various cell types under different conditions. PMID:26987813

  11. Markets, religion, regulation

    DEFF Research Database (Denmark)

    Fischer, Johan

    2016-01-01

    of regulation, certification and standardization on a global scale. Building on research on global kosher (a Hebrew term meaning “fit” or “proper”), halal (an Arabic word that literally means “permissible” or “lawful”) and Hindu vegetarianism this paper argues that these economies or markets to a large extent...... are conditioned by and themselves condition forms of transnational governmentality, that is, new and often overlapping practices of government and grassroots politics. I explore religious economies and markets at three interrelated levels of the social scale: state and non-state regulation, the marketplace......Most recent scholarship on moral economies or religious markets argues for the compatibility of economies/markets and religious practices in particular national or regional contexts. However, over the last couple of decades or so religious markets have entered a new phase characterized by new forms...

  12. Regulation of Meiotic Recombination

    Energy Technology Data Exchange (ETDEWEB)

    Gregory p. Copenhaver

    2011-11-09

    Meiotic recombination results in the heritable rearrangement of DNA, primarily through reciprocal exchange between homologous chromosome or gene conversion. In plants these events are critical for ensuring proper chromosome segregation, facilitating DNA repair and providing a basis for genetic diversity. Understanding this fundamental biological mechanism will directly facilitate trait mapping, conventional plant breeding, and development of genetic engineering techniques that will help support the responsible production and conversion of renewable resources for fuels, chemicals, and the conservation of energy (1-3). Substantial progress has been made in understanding the basal recombination machinery, much of which is conserved in organisms as diverse as yeast, plants and mammals (4, 5). Significantly less is known about the factors that regulate how often and where that basal machinery acts on higher eukaryotic chromosomes. One important mechanism for regulating the frequency and distribution of meiotic recombination is crossover interference - or the ability of one recombination event to influence nearby events. The MUS81 gene is thought to play an important role in regulating the influence of interference on crossing over. The immediate goals of this project are to use reverse genetics to identify mutants in two putative MUS81 homologs in the model plant Arabidopsis thaliana, characterize those mutants and initiate a novel forward genetic screen for additional regulators of meiotic recombination. The long-term goal of the project is to understand how meiotic recombination is regulated in higher eukaryotes with an emphasis on the molecular basis of crossover interference. The ability to monitor recombination in all four meiotic products (tetrad analysis) has been a powerful tool in the arsenal of yeast geneticists. Previously, the qrt mutant of Arabidopsis, which causes the four pollen products of male meiosis to remain attached, was developed as a facile system

  13. POTENT REGULATORS OF METABOLISM

    OpenAIRE

    Brun, Pierre-Jacques; Yang, Kryscilla Jian Zhang; Lee, Seung-Ah; Yuen, Jason J.; Blaner, William S.

    2012-01-01

    Retinoids (vitamin A and its analogs) are highly potent regulators of cell differentiation, cell proliferation, and apoptosis. Because of these activities, retinoids have been most extensively studied in the contexts of embryonic development and of proliferative diseases, especially cancer and skin disease. Recently, there has been considerable new research interest focused on gaining understanding of the roles that retinoids and/or retinoid-related proteins may have in the development of met...

  14. Beyond State Regulation

    OpenAIRE

    Madanat, Philip; Pies, Judith

    2011-01-01

    Holding the news media accountable has traditionally been a task of the state in Jordan. Media laws and regulations are numerous and do not leave too much space for self-regulatory practices on a national basis. The Jordan Press Association (JPA) is the core of so-called established media accountability institutions. It conducted a law-like code of ethics in 2003 and runs ombuds committees (currently three) dealing with mishaps of the media to prevent journalists from legal liability. Thou...

  15. Fibronectin Mechanobiology Regulates Tumorigenesis

    OpenAIRE

    Wang, Karin; Seo, Bo Ri; Fischbach, Claudia; Gourdon, Delphine

    2015-01-01

    Fibronectin (Fn) is an essential extracellular matrix (ECM) glycoprotein involved in both physiological and pathological processes. The structure–function relationship of Fn has been and is still being studied, as changes in its molecular structure are integral in regulating (or dysregulating) its biological activities via its cell, matrix component, and growth factor binding sites. Fn comprises three types of repeating modules; among them, FnIII modules are mechanically unstable domains that...

  16. Iron regulation by hepcidin

    OpenAIRE

    Zhao, Ningning; Zhang, An-Sheng; Enns, Caroline A

    2013-01-01

    Hepcidin is a key hormone that is involved in the control of iron homeostasis in the body. Physiologically, hepcidin is controlled by iron stores, inflammation, hypoxia, and erythropoiesis. The regulation of hepcidin expression by iron is a complex process that requires the coordination of multiple proteins, including hemojuvelin, bone morphogenetic protein 6 (BMP6), hereditary hemochromatosis protein, transferrin receptor 2, matriptase-2, neogenin, BMP receptors, and transferrin. Misregulati...

  17. Human telomerase activity regulation

    OpenAIRE

    Wojtyla, Aneta; Gladych, Marta; Rubis, Blazej

    2010-01-01

    Telomerase has been recognized as a relevant factor distinguishing cancer cells from normal cells. Thus, it has become a very promising target for anticancer therapy. The cell proliferative potential can be limited by replication end problem, due to telomeres shortening, which is overcome in cancer cells by telomerase activity or by alternative telomeres lengthening (ALT) mechanism. However, this multisubunit enzymatic complex can be regulated at various levels, including expression control b...

  18. Cyberplagiarism in University Regulations

    OpenAIRE

    Santiago Cavanillas

    2008-01-01

    The article examines the legal framework for plagiarism, and its twofold nature of illicit appropriation (from the author of the plagiarized work) and fraud (with regard to the target audience of the plagiarism). Based on these premises, academic cyberplagiarism is analysed as a form of plagiarism carried out using electronic tools in the university setting. The question of responsibility (who can regulate the legal consequences of plagiarism?) before and after the Ley Orgánica de Universidad...

  19. Gastrointestinal hormones regulating appetite

    OpenAIRE

    Chaudhri, Owais; Small, Caroline; Bloom, Steve

    2006-01-01

    The role of gastrointestinal hormones in the regulation of appetite is reviewed. The gastrointestinal tract is the largest endocrine organ in the body. Gut hormones function to optimize the process of digestion and absorption of nutrients by the gut. In this capacity, their local effects on gastrointestinal motility and secretion have been well characterized. By altering the rate at which nutrients are delivered to compartments of the alimentary canal, the control of food intake arguably cons...

  20. Auditing and Regulations

    OpenAIRE

    Pettinicchio, A.K.

    2011-01-01

    Effective financial reporting has become of critical importance in our economic markets and the international accounting scandals of the last decades have accentuated the role of auditing in protecting stakeholders' interests and contributing to an efficient functioning of financial markets. Auditing regulation has been at the centre of recent international debates (e.g. EU Green paper; 2010) and different regulatory interventions have been put in place in different countries and in different...