Joseph J Abrajano
Full Text Available BACKGROUND: The repressor element-1 (RE1 silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF is a master transcriptional regulator that binds to numerous genomic RE1 sites where it acts as a molecular scaffold for dynamic recruitment of modulatory and epigenetic cofactors, including corepressor for element-1-silencing transcription factor (CoREST. CoREST also acts as a hub for various cofactors that play important roles in epigenetic remodeling and transcriptional regulation. While REST can recruit CoREST to its macromolecular complex, CoREST complexes also function at genomic sites independently of REST. REST and CoREST perform a broad array of context-specific functions, which include repression of neuronal differentiation genes in neural stem cells (NSCs and other non-neuronal cells as well as promotion of neurogenesis. Despite their involvement in multiple aspects of neuronal development, REST and CoREST are not believed to have any direct modulatory roles in glial cell maturation. METHODOLOGY/PRINCIPAL FINDINGS: We challenged this view by performing the first study of REST and CoREST in NSC-mediated glial lineage specification and differentiation. Utilizing ChIP on chip (ChIP-chip assays, we identified distinct but overlapping developmental stage-specific profiles for REST and CoREST target genes during astrocyte (AS and oligodendrocyte (OL lineage specification and OL lineage maturation and myelination, including many genes not previously implicated in glial cell biology or linked to REST and CoREST regulation. Amongst these factors are those implicated in macroglial (AS and OL cell identity, maturation, and maintenance, such as members of key developmental signaling pathways and combinatorial transcription factor codes. CONCLUSIONS/SIGNIFICANCE: Our results imply that REST and CoREST modulate not only neuronal but also glial lineage elaboration. These factors may therefore mediate critical developmental processes
Full Text Available Abstract Background Long non-protein-coding RNAs (ncRNAs are emerging as important regulators of cellular differentiation and are widely expressed in the brain. Results Here we show that many long ncRNAs exhibit dynamic expression patterns during neuronal and oligodendrocyte (OL lineage specification, neuronal-glial fate transitions, and progressive stages of OL lineage elaboration including myelination. Consideration of the genomic context of these dynamically regulated ncRNAs showed they were part of complex transcriptional loci that encompass key neural developmental protein-coding genes, with which they exhibit concordant expression profiles as indicated by both microarray and in situ hybridization analyses. These included ncRNAs associated with differentiation-specific nuclear subdomains such as Gomafu and Neat1, and ncRNAs associated with developmental enhancers and genes encoding important transcription factors and homeotic proteins. We also observed changes in ncRNA expression profiles in response to treatment with trichostatin A, a histone deacetylase inhibitor that prevents the progression of OL progenitors into post-mitotic OLs by altering lineage-specific gene expression programs. Conclusion This is the first report of long ncRNA expression in neuronal and glial cell differentiation and of the modulation of ncRNA expression by modification of chromatin architecture. These observations explicitly link ncRNA dynamics to neural stem cell fate decisions, specification and epigenetic reprogramming and may have important implications for understanding and treating neuropsychiatric diseases.
Marinelli, Carla; Bertalot, Thomas; Zusso, Morena; Skaper, Stephen D; Giusti, Pietro
Oligodendrogenesis and oligodendrocyte precursor maturation are essential processes during the course of central nervous system development, and lead to the myelination of axons. Cells of the oligodendrocyte lineage are generated in the germinal zone from migratory bipolar oligodendrocyte precursor cells (OPCs), and acquire cell surface markers as they mature and respond specifically to factors which regulate proliferation, migration, differentiation, and survival. Loss of myelin underlies a wide range of neurological disorders, some of an autoimmune nature-multiple sclerosis probably being the most prominent. Current therapies are based on the use of immunomodulatory agents which are likely to promote myelin repair (remyelination) indirectly by subverting the inflammatory response, aspects of which impair the differentiation of OPCs. Cells of the oligodendrocyte lineage express and are capable of responding to a diverse array of ligand-receptor pairs, including neurotransmitters and nuclear receptors such as γ-aminobutyric acid, glutamate, adenosine triphosphate, serotonin, acetylcholine, nitric oxide, opioids, prostaglandins, prolactin, and cannabinoids. The intent of this review is to provide the reader with a synopsis of our present state of knowledge concerning the pharmacological properties of the oligodendrocyte lineage, with particular attention to these receptor-ligand (i.e., neurotransmitters and nuclear receptor) interactions that can influence oligodendrocyte migration, proliferation, differentiation, and myelination, and an appraisal of their therapeutic potential. For example, many promising mediators work through Ca(2+) signaling, and the balance between Ca(2+) influx and efflux can determine the temporal and spatial properties of oligodendrocytes (OLs). Moreover, Ca(2+) signaling in OPCs can influence not only differentiation and myelination, but also process extension and migration, as well as cell death in mature mouse OLs. There is also evidence
Full Text Available OOligodendrogenesis and oligodendrocyte precursor maturation are essential processes during the course of central nervous system development, and lead to the myelination of axons. Cells of the oligodendrocyte lineage are generated in the germinal zone from migratory bipolar oligodendrocyte precursor cells, and acquire cell surface markers as they mature and respond specifically to factors which regulate proliferation, migration, differentiation, and survival. Loss of myelin underlies a wide range of neurological disorders, some of an autoimmune nature – multiple sclerosis probably being the most prominent. Current therapies are based on the use of immunomodulatory agents which are likely to promote myelin repair (remyelination indirectly by subverting the inflammatory response, aspects of which impair the differentiation of oligodendrocyte precursor cells. Cells of the oligodendrocyte lineage express and are capable of responding to a diverse array of ligand-receptor pairs, including neurotransmitters and nuclear receptors such as gamma-aminobutyric acid, glutamate, ATP, serotonin, acetylcholine, nitric oxide, opioids, prostaglandins, prolactin, cannabinoids and nuclear receptors. The intent of this review is to provide the reader with a synopsis of our present state of knowledge concerning the pharmacological properties of the oligodendrocyte lineage, with particular attention to these receptor-ligand (i.e., neurotransmitters and nuclear receptor interactions that can influence oligodendrocyte migration, proliferation, differentiation, and myelination, and an appraisal of their therapeutic potential. For example, many promising mediators work through Ca2+ signalling, and the balance between Ca2+ influx and efflux can determine the temporal and spatial properties of oligodendrocytes. Moreover, Ca2+ signalling in oligodendrocyte precursor cells can influence not only differentiation and myelination, but also process extension and migration, as
Marinelli, Carla; Bertalot, Thomas; Zusso, Morena; Skaper, Stephen D.; Giusti, Pietro
Oligodendrogenesis and oligodendrocyte precursor maturation are essential processes during the course of central nervous system development, and lead to the myelination of axons. Cells of the oligodendrocyte lineage are generated in the germinal zone from migratory bipolar oligodendrocyte precursor cells (OPCs), and acquire cell surface markers as they mature and respond specifically to factors which regulate proliferation, migration, differentiation, and survival. Loss of myelin underlies a wide range of neurological disorders, some of an autoimmune nature—multiple sclerosis probably being the most prominent. Current therapies are based on the use of immunomodulatory agents which are likely to promote myelin repair (remyelination) indirectly by subverting the inflammatory response, aspects of which impair the differentiation of OPCs. Cells of the oligodendrocyte lineage express and are capable of responding to a diverse array of ligand-receptor pairs, including neurotransmitters and nuclear receptors such as γ-aminobutyric acid, glutamate, adenosine triphosphate, serotonin, acetylcholine, nitric oxide, opioids, prostaglandins, prolactin, and cannabinoids. The intent of this review is to provide the reader with a synopsis of our present state of knowledge concerning the pharmacological properties of the oligodendrocyte lineage, with particular attention to these receptor-ligand (i.e., neurotransmitters and nuclear receptor) interactions that can influence oligodendrocyte migration, proliferation, differentiation, and myelination, and an appraisal of their therapeutic potential. For example, many promising mediators work through Ca2+ signaling, and the balance between Ca2+ influx and efflux can determine the temporal and spatial properties of oligodendrocytes (OLs). Moreover, Ca2+ signaling in OPCs can influence not only differentiation and myelination, but also process extension and migration, as well as cell death in mature mouse OLs. There is also evidence
Copray, Sjef; Huynh, Jimmy Long; Sher, Falak; Casaccia-Bonnefil, Patrizia; Boddeke, Erik
The process of oligodendrocyte differentiation is regulated by a dynamic interaction between a genetic and an epigenetic program. Recent studies, addressing nucleosomal histone modifications have considerably increased our knowledge regarding epigenetic regulation of gene expression during oligodendrocyte development and aging. These results have generated new hypotheses regarding the mechanisms underlying the decreased efficiency of endogenous remyelination in response to demyelinating injuries with increasing age. In this review, we present an overview of the epigenetic mechanisms regulating gene expression at specific stages of oligodendrocyte differentiation and maturation as well as the changes that occur with aging.
Chattopadhyay, N.; Espinosa-Jeffrey, A.; Yano, S.
Oligodendrocytes develop from oligodendrocyte progenitor cells (OPCs), which in turn arise from a subset of neuroepithelial precursor cells during midneurogenesis. Development of the oligodendrocyte lineage involves a plethora of cell-intrinsic and -extrinsic signals. A cell surface calcium......-sensing receptor (CaR) has been shown to be functionally expressed in immature oligodendrocytes. Here, we investigated the expression and function of the CaR during oligodendrocyte development. We show that the order of CaR mRNA expression as assessed by quantitative polymerase chain reaction is mature...... oligodendrocyte > neuron > astrocyte. We next determined the rank order of CaR expression on inducing specification of neural stem cells to the neuronal, oligodendroglial, or astrocytic lineages and found that the relative levels of CaR mRNA expression are OPC > neuron > astrocytes. CaR mRNA expression in cells...
Li, Jiasi; Zhang, Lei; Chu, Yongxin; Namaka, Michael; Deng, Benqiang; Kong, Jiming; Bi, Xiaoying
White matter is primarily composed of myelin and myelinated axons. Structural and functional completeness of myelin is critical for the reliable and efficient transmission of information. White matter injury has been associated with the development of many demyelinating diseases. Despite a variety of scientific advances aimed at promoting re-myelination, their benefit has proven at best to be marginal. Research suggests that the failure of the re-myelination process may be the result of an unfavorable microenvironment. Astrocytes, are the most ample and diverse type of glial cells in central nervous system (CNS) which display multiple functions for the cells of the oligodendrocytes lineage. As such, much attention has recently been drawn to astrocyte function in terms of white matter myelin repair. They are different in white matter from those in gray matter in specific regards to development, morphology, location, protein expression and other supportive functions. During the process of demyelination and re-myelination, the functions of astrocytes are dynamic in that they are able to change functions in accordance to different time points, triggers or reactive pathways resulting in vastly different biologic effects. They have pivotal effects on oligodendrocytes and other cell types in the oligodendrocyte lineage by serving as an energy supplier, a participant of immunological and inflammatory functions, a source of trophic factors and iron and a sustainer of homeostasis. Astrocytic impairment has been shown to be directly linked to the development of neuromyelities optica (NMO). In addition, astroctyes have also been implicated in other white matter conditions such as psychiatric disorders and neurodegenerative diseases such as Alzheimer’s disease (AD), multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). Inhibiting specifically detrimental signaling pathways in astrocytes while preserving their beneficial functions may be a promising approach for
Full Text Available White matter is primarily composed of myelin and myelinated axons. Structural and functional completeness of myelin is critical for the reliable and efficient transmission of information. White matter injury has been associated with the development of many demyelinating diseases. Despite a variety of scientific advances aimed at promoting re-myelination, their benefit has proven at best to be marginal. Research suggests that the failure of the re-myelination process may be the result of an unfavorable microenvironment. Astrocytes, are the most ample and diverse type of glial cells in central nervous system which display multiple functions for the cells of the oligodendrocytes lineage. As such, much attention has recently been drawn to astrocyte function in terms of white matter myelin repair. They are different in white matter from those in grey matter in specific regards to development, morphology, location, protein expression and other supportive functions. During the process of demyelination and re-myelination, the functions of astrocytes are dynamic in that they are able to change functions in accordance to different time points, triggers or reactive pathways resulting in vastly different biologic effects. They have pivotal effects on oligodendrocytes and other cell types in the oligodendrocyte lineage by serving as an energy supplier, a participant of immunological and inflammatory functions, a source of trophic factors and iron and a sustainer of homeostasis. Astrocytic impairment has been shown to be directly linked to the development of neuromyelities optica. In addition, astroctyes have also been implicated in other white matter conditions such as psychiatric disorders and neurodegenerative diseases such as Alzheimer’s disease, multiple sclerosis and amyotrophic lateral sclerosis. Inhibiting specifically detrimental signaling pathways in astrocytes while preserving their beneficial functions may be a promising approach for
Nakajima, Mitsunari; Shimizu, Risei; Furuta, Kohei; Sugino, Mami; Watanabe, Takashi; Aoki, Rui; Okuyama, Satoshi; Furukawa, Yoshiko
We investigated the effects of auraptene on mouse oligodendroglial cell lineage in an animal model of demyelination induced by cuprizone. Auraptene, a citrus coumarin, was intraperitoneally administered to mice fed the demyelinating agent cuprizone. Immunohistochemical analysis of the corpus callosum and/or Western blotting analysis of brain extracts revealed that cuprizone reduced immunoreactivity for myelin-basic protein, a marker of myelin, whereas it increased immunoreactivity to platelet derived-growth factor receptor-α, a marker of oligodendrocyte precursor cells. Administration of auraptene enhanced the immunoreactivity to oligodendrocyte transcription factor 2, a marker of oligodendrocyte precursor cells and oligodendrocyte lineage precursor cells, but had no effect on immunoreactivity to myelin-basic protein or platelet-derived growth factor receptor-α. These findings suggest that auraptene promotes the production of oligodendrocyte lineage precursor cells in an animal model of demyelination and may be useful for individuals with demyelinating diseases. Copyright © 2016 Elsevier B.V. All rights reserved.
Chattopadhyay, Naibedya; Espinosa-Jeffrey, Araceli; Tfelt-Hansen, Jacob; Yano, Shozo; Bandyopadhyay, Sanghamitra; Brown, Edward M; de Vellis, Jean
Oligodendrocytes develop from oligodendrocyte progenitor cells (OPCs), which in turn arise from a subset of neuroepithelial precursor cells during midneurogenesis. Development of the oligodendrocyte lineage involves a plethora of cell-intrinsic and -extrinsic signals. A cell surface calcium-sensing receptor (CaR) has been shown to be functionally expressed in immature oligodendrocytes. Here, we investigated the expression and function of the CaR during oligodendrocyte development. We show that the order of CaR mRNA expression as assessed by quantitative polymerase chain reaction is mature oligodendrocyte > neuron > astrocyte. We next determined the rank order of CaR expression on inducing specification of neural stem cells to the neuronal, oligodendroglial, or astrocytic lineages and found that the relative levels of CaR mRNA expression are OPC > neuron > astrocytes. CaR mRNA expression in cells at various stages of development along the oligodendrocyte lineage revealed that its expression is robustly up-regulated during the OPC stage and remains high until the premyelinating stage, decreasing thereafter by severalfold in the mature oligodendrocyte. In OPCs, high Ca(2+) acting via the CaR promotes cellular proliferation. We further observed that high Ca(2+) stimulates the mRNA levels of myelin basic protein in preoligodendrocytes, which is also CaR mediated. Finally, myelin basic protein levels were significantly reduced in the cerebellum of CaR-null mice during development. Our results show that CaR expression is up-regulated when neural stem cells are specified to the oligodendrocyte lineage and that activation of the receptor results in OPC expansion and differentiation. We conclude that the CaR may be a novel regulator of oligodendroglial development and function.
Full Text Available In this study, we sought evidence for alpha-synuclein (ASYN expression in oligodendrocytes, as a possible endogenous source of ASYN to explain its presence in glial inclusions found in multiple system atrophy (MSA and Parkinson’s disease (PD. We identified ASYN in oligodendrocyte lineage progenitors isolated from the rodent brain, in oligodendrocytes generated from embryonic stem cells, and in induced pluripotent stem cells produced from fibroblasts of a healthy individual and patients diagnosed with MSA or PD, in cultures in vitro. Notably, we observed a significant decrease in ΑSYN during oligodendrocyte maturation. Additionally, we show the presence of transcripts in PDGFRΑ/CD140a+ cells and SOX10+ oligodendrocyte lineage nuclei isolated by FACS from rodent and human healthy and diseased brains, respectively. Our work identifies ASYN in oligodendrocyte lineage cells, and it offers additional in vitro cellular models that should provide significant insights of the functional implication of ASYN during oligodendrocyte development and disease.
Pozniak, Christine D.; Langseth, Abraham J.; Dijkgraaf, Gerrit J. P.; Choe, Youngshik; Werb, Zena; Pleasure, Samuel J.
Oligodendrocyte precursor cells (OPCs) are lineage-restricted progenitors generally limited in vivo to producing oligodendrocytes. Mechanisms controlling genesis of OPCs are of interest because of their importance in myelin development and their potential for regenerative therapies in multiple sclerosis and dysmyelinating syndromes. We show here that the SoxE transcription factors (comprising Sox8, 9, and 10) induce multipotent neural precursor cells (NPCs) from the early postnatal subventricular zone (SVZ) to become OPCs in an autonomous manner. We performed a chromatin immunoprecipitation-based bioinformatic screen and identified Suppressor of Fused (Sufu) as a direct target of repression by Sox10. In vitro, overexpression of Sufu blocked OPC production, whereas RNAi-mediated inhibition augmented OPC production. Furthermore, mice heterozygous for Sufu have increased numbers of OPCs in the telencephalon during development. We conclude that Sox10 acts to restrict the potential of NPCs toward the oligodendrocyte lineage in part by regulating the expression of Sufu. PMID:21098272
Copray, Sjef; Huynh, Jimmy Long; Sher, Falak; Casaccia-Bonnefil, Patrizia; Boddeke, Erik
The process of oligodendrocyte differentiation is regulated by a dynamic interaction between a genetic and an epigenetic program. Recent studies, addressing nucleosomal histone modifications have considerably increased our knowledge regarding epigenetic regulation of gene expression during oligodend
Lijun Yang; Hong Cui; Ting Cao
Oligodendrocyte lineage gene 1 plays a key role in hypoxic-ischemic brain damage and myelin repair. miRNA-9 is involved in the occurrence of many related neurological disorders. Bioin-formatics analysis demonstrated that miRNA-9 complementarily, but incompletely, bound oligodendrocyte lineage gene 1, but whether miRNA-9 regulates oligodendrocyte lineage gene 1 remains poorly understood. Whole brain slices of 3-day-old Sprague-Dawley rats were cultured and divided into four groups:control group;oxygen-glucose deprivation group (treatment with 8% O2+ 92%N2 and sugar-free medium for 60 minutes);transfection control group (after oxygen and glucose deprivation for 60 minutes, transfected with control plasmid) and miRNA-9 transfection group (after oxygen and glucose deprivation for 60 minutes, transfected with miRNA-9 plasmid). From the third day of transfection, and with increasing culture days, oligodendrocyte lineage gene 1 expression increased in each group, peaked at 14 days, and then decreased at 21 days. Real-time quantitative PCR results, however, demonstrated that oligoden-drocyte lineage gene 1 expression was lower in the miRNA-9 transfection group than that in the transfection control group at 1, 3, 7, 14, 21 and 28 days after transfection. Results suggested that miRNA-9 possibly negatively regulated oligodendrocyte lineage gene 1 in brain tissues during hypoxic-ischemic brain damage.
Sullivan, Genevieve M; Mierzwa, Amanda J; Kijpaisalratana, Naruchorn; Tang, Haiying; Wang, Yong; Song, Sheng-Kwei; Selwyn, Reed; Armstrong, Regina C
Traumatic brain injury frequently causes traumatic axonal injury (TAI) in white matter tracts. Experimental TAI in the corpus callosum of adult mice was used to examine the effects on oligodendrocyte lineage cells and myelin in conjunction with neuroimaging. The injury targeted the corpus callosum over the subventricular zone, a source of neural stem/progenitor cells. Traumatic axonal injury was produced in the rostral body of the corpus callosum by impact onto the skull at the bregma. During the first week after injury, magnetic resonance diffusion tensor imaging showed that axial diffusivity decreased in the corpus callosum and that corresponding regions exhibited significant axon damage accompanied by hypertrophic microglia and reactive astrocytes. Oligodendrocyte progenitor proliferation increased in the subventricular zone and corpus callosum. Oligodendrocytes in the corpus callosum shifted toward upregulation of myelin gene transcription. Plp/CreER(T):R26IAP reporter mice showed normal reporter labeling of myelin sheaths 0 to 2 days after injury but labeling was increased between 2 and 7 days after injury. Electron microscopy revealed axon degeneration, demyelination, and redundant myelin figures. These findings expand the cell types and responses to white matter injuries that inform diffusion tensor imaging evaluation and identify pivotal white matter changes after TAI that may affect axon vulnerability vs. recovery after brain injury.
Butt, A M; Ibrahim, M; Berry, M
Myelinogenesis was investigated in whole-mounted anterior medullary vela from rats aged postnatal day (P) 10-12, using double immunofluorescence labelling with Rip and anti-neurofilament 200 (NF200) antibodies, to identify oligodendrocytes and axons, respectively. A number of discrete phases of maturation of oligodendrocyte units were recognised. (1) Promyelinating oligodendrocytes co-expressed Rip and Myelin basic Protein and formed axonal associations, prior to ensheathment. (2) Transitional oligodendrocytes contained both ensheathing and non-ensheating processes. (3) Myelinating oligodendrocytes were established after a period of remodelling (in which non-ensheathing processes were lost), appearing as oligodendrocyte unit morphological phenotypes with a definitive number of incipient myelin sheaths. (4) Maturation of myelinating oligodendrocytes was defined as the establishment of internodal sheath lengths and the redistrubution of myelin basic protein from the cell somata and radial processes into the myelin sheaths only. Myelination was probably related to the maturational state of the axons, since it was initiated when the latter had attained a critical diameter of between approximately 0.2 and 0.4 micron, coincident with the expression of NF200. Oligodendrocyte differentiation and myelination of the AMV were asynchronous and multifocal, and at P10: (1) axons which were destined to be of the largest calibre in the adult AMV were already myelinated by early developing oligodendrocytes, whilst those which were destined to be the smallest calibre in the adult were unmyelinated, but ultimately became ensheathed by late developing oligoendrocytes; (2) axons were sequentially ensheathed by early developing myelinating oligodendrocytes and late developing promyelinating oligodendrocytes; (3) all axons were small calibre; (4) oligodendrocyte units exhibited polymorphism. Thus, the development of oligodendrocyte morphological phenotypes was not related solely to
Hong Cui; Weijuan Han; Lijun Yang; Yanzhong Chang
Oligodendrocyte lineage gene-1 expressed in oligodendrocytes may trigger the repair of neuronal myelin impairment, and play a crucial role in myelin repair. Hypoxia-inducible factor 1α, a transcription factor, is of great significance in premature infants with hypoxic-ischemic brain damage. There is little evidence of direct regulatory effects of hypoxia-inducible factor 1α on oligodendrocyte lineage gene-1. In this study, brain slices of Sprague-Dawley rats were cultured and subjected to oxygen-glucose deprivation. Then, slices were transfected with hypoxia-inducible factor 1α or oligodendrocyte lineage gene-1. The expression levels of hypoxia-inducible factor 1α and oligodendrocyte lineage gene-1 were significantly up-regulated in rat brains prior to transfection, as detected by immunohistochemical staining. Eight hours after transfection of slices with hypoxia-inducible factor 1α, oligodendrocyte lineage gene-1 expression was upregulated, and reached a peak 24 hours after transfection. Oligodendrocyte lineage gene-1 transfection induced no significant differences in hypoxia-inducible factor 1α levels in rat brain tissues with oxygen-glucose deprivation. These experimental findings indicate that hypoxia-inducible factor 1α can regulate oligodendrocyte lineage gene-1 expression in hypoxic brain tissue, thus repairing the neural impairment.
Erin C Jacobs
Full Text Available Recently, several in vitro studies have shown that the golli-myelin basic proteins regulate Ca2+ homoeostasis in OPCs (oligodendrocyte precursor cells and immature OLs (oligodendrocytes, and that a number of the functions of these cells are affected by cellular levels of the golli proteins. To determine the influence of golli in vivo on OL development and myelination, a transgenic mouse was generated in which the golli isoform J37 was overexpressed specifically within OLs and OPCs. The mouse, called JOE (J37-overexpressing, is severely hypomyelinated between birth and postnatal day 50. During this time, it exhibits severe intention tremors that gradually abate at later ages. After postnatal day 50, ultrastructural studies and Northern and Western blot analyses indicate that myelin accumulates in the brain, but never reaches normal levels. Several factors appear to underlie the extensive hypomyelination. In vitro and in vivo experiments indicate that golli overexpression causes a significant delay in OL maturation, with accumulation of significantly greater numbers of pre-myelinating OLs that fail to myelinate axons during the normal myelinating period. Immunohistochemical studies with cell death and myelin markers indicate that JOE OLs undergo a heightened and extended period of cell death and are unable to effectively myelinate until 2 months after birth. The results indicate that increased levels of golli in OPC/OLs delays myelination, causing significant cell death of OLs particularly in white matter tracts. The results provide in vivo evidence for a significant role of the golli proteins in the regulation of maturation of OLs and normal myelination.
Pernet, Vincent; Joly, Sandrine; Christ, Franziska; Dimou, Leda; Schwab, Martin E
Nogo-A is one of the most potent oligodendrocyte-derived inhibitors for axonal regrowth in the injured adult CNS. However, the physiological function of Nogo-A in development and in healthy oligodendrocytes is still unknown. In the present study, we investigated the role of Nogo-A for myelin formation in the developing optic nerve. By quantitative real-time PCR, we found that the expression of Nogo-A increased faster in differentiating oligodendrocytes than that of the major myelin proteins MBP (myelin basic protein), PLP (proteolipid protein)/DM20, and CNP (2',3'-cyclic nucleotide 3'-phosphodiesterase). The analysis of optic nerves and cerebella of mice deficient for Nogo-A (Nogo-A(-/-)) revealed a marked delay of oligodendrocyte differentiation, myelin sheath formation, and axonal caliber growth within the first postnatal month. The combined deletion of Nogo-A and MAG caused a more severe transient hypomyelination. In contrast to MAG(-/-) mice, Nogo-A(-/-) mutants did not present abnormalities in the structure of myelin sheaths and Ranvier nodes. The common binding protein for Nogo-A and MAG, NgR1, was exclusively upregulated in MAG(-/-) animals, whereas the level of Lingo-1, a coreceptor, remained unchanged. Together, our results demonstrate that Nogo-A and MAG are differently involved in oligodendrocyte maturation in vivo, and suggest that Nogo-A may influence also remyelination in pathological conditions such as multiple sclerosis.
Jensen, Brigid K; Monnerie, Hubert; Mannell, Maggie V; Gannon, Patrick J; Espinoza, Cagla Akay; Erickson, Michelle A; Bruce-Keller, Annadora J; Gelman, Benjamin B; Briand, Lisa A; Pierce, R Christopher; Jordan-Sciutto, Kelly L; Grinspan, Judith B
Despite effective viral suppression through combined antiretroviral therapy (cART), approximately half of HIV-positive individuals have HIV-associated neurocognitive disorders (HAND). Studies of antiretroviral-treated patients have revealed persistent white matter abnormalities including diffuse myelin pallor, diminished white matter tracts, and decreased myelin protein mRNAs. Loss of myelin can contribute to neurocognitive dysfunction because the myelin membrane generated by oligodendrocytes is essential for rapid signal transduction and axonal maintenance. We hypothesized that myelin changes in HAND are partly due to effects of antiretroviral drugs on oligodendrocyte survival and/or maturation. We showed that primary mouse oligodendrocyte precursor cell cultures treated with therapeutic concentrations of HIV protease inhibitors ritonavir or lopinavir displayed dose-dependent decreases in oligodendrocyte maturation; however, this effect was rapidly reversed after drug removal. Conversely, nucleoside reverse transcriptase inhibitor zidovudine had no effect. Furthermore, in vivo ritonavir administration to adult mice reduced frontal cortex myelin protein levels. Finally, prefrontal cortex tissue from HIV-positive individuals with HAND on cART showed a significant decrease in myelin basic protein compared with untreated HIV-positive individuals with HAND or HIV-negative controls. These findings demonstrate that antiretrovirals can impact myelin integrity and have implications for myelination in juvenile HIV patients and myelin maintenance in adults on lifelong therapy.
Tomassy, Giulio Srubek; Fossati, Valentina
Since monumental studies from scientists like His, Ramón y Cajal, Lorente de Nó and many others have put down roots for modern neuroscience, the scientific community has spent a considerable amount of time, and money, investigating any possible aspect of the evolution, development and function of neurons. Today, the complexity and diversity of myriads of neuronal populations, and their progenitors, is still focus of extensive studies in hundreds of laboratories around the world. However, our prevalent neuron-centric perspective has dampened the efforts in understanding glial cells, even though their active participation in the brain physiology and pathophysiology has been increasingly recognized over the years. Among all glial cells of the central nervous system (CNS), oligodendrocytes (OLs) are a particularly specialized type of cells that provide fundamental support to neuronal activity by producing the myelin sheath. Despite their functional relevance, the developmental mechanisms regulating the generation of OLs are still poorly understood. In particular, it is still not known whether these cells share the same degree of heterogeneity of their neuronal companions and whether multiple subtypes exist within the lineage. Here, we will review and discuss current knowledge about OL development and function in the brain and spinal cord. We will try to address some specific questions: do multiple OL subtypes exist in the CNS? What is the evidence for their existence and those against them? What are the functional features that define an oligodendrocyte? We will end our journey by reviewing recent advances in human pluripotent stem cell differentiation towards OLs. This exciting field is still at its earliest days, but it is quickly evolving with improved protocols to generate functional OLs from different spatial origins. As stem cells constitute now an unprecedented source of human OLs, we believe that they will become an increasingly valuable tool for deciphering
Giulio eSrubek Tomassy
Full Text Available Since monumental studies from scientists like His, Ramón y Cajal, Lorente de Nó and many others have put down roots for modern neuroscience, the scientific community has spent a considerable amount of time, and money, investigating any aspect of the evolution, development and function of neurons. Today, the complexity and diversity of myriads of neuronal populations is still focus of extensive studies in hundreds of laboratories around the world. However, our prevalent neuron-centric perspective has dampened the efforts in understanding glial cells, even though their active participation in the brain physiology and pathophysiology has been increasingly recognized over the years. Among all glial cells of the central nervous system (CNS, oligodendrocytes (OLs are a particularly specialized type of cells that provide fundamental support to neuronal activity by producing the myelin sheath. Despite their functional relevance, the developmental mechanisms regulating the generation of OLs are still poorly understood. In particular, it is still not known whether these cells share the same degree of heterogeneity of their neuronal companions and whether multiple subtypes exist within the lineage. Here, we will review and discuss current knowledge about OL development and function in the brain and spinal cord. We will try to address some specific questions: do multiple OL subtypes exist in the CNS? What is the evidence for their existence and those against them? What are the functional features that define an oligodendrocyte? We will end our journey by reviewing recent advances in human pluripotent stem cell differentiation towards OLs. This exciting field is still at its earliest days, but it is quickly evolving with improved protocols to generate functional OLs from different spatial origins. As stem cells constitute now an unprecedented source of human OLs, we believe that they will become an increasingly valuable tool for deciphering the complexity
Ravi Shankar Akundi
Full Text Available BACKGROUND: Periventricular white matter injury (PWMI is a common form of brain injury sustained by preterm infants. A major factor that predisposes to PWMI is hypoxia. Because oligodendrocytes (OLs are responsible for myelination of axons, abnormal OL development or function may affect brain myelination. At present our understanding of the influences of hypoxia on OL development is limited. To examine isolated effects of hypoxia on OLs, we examined the influences of hypoxia on OL development in vitro. METHODOLOGY/FINDINGS: Cultures of oligodendrocyte precursor cells (OPCs were prepared from mixed glial cultures and were 99% pure. OPCs were maintained at 21% O(2 or hypoxia (1% or 4% O(2 for up to 7 days. We observed that 1% O(2 lead to an increase in the proportion of myelin basic protein (MBP-positive OLs after 1 week in culture, and a decrease in the proportion of platelet-derived growth factor receptor alpha (PDGFRalpha-positive cells suggesting premature OL maturation. Increased expression of the cell cycle regulatory proteins p27(Kip1 and phospho-cdc2, which play a role in OL differentiation, was seen as well. CONCLUSIONS: These results show that hypoxia interferes with the normal process of OL differentiation by inducing premature OPC maturation.
Ravanelli, Andrew M; Appel, Bruce
During spinal cord development, ventral neural progenitor cells that express the transcription factors Olig1 and Olig2, called pMN progenitors, produce motor neurons and then oligodendrocytes. Whether motor neurons and oligodendrocytes arise from common or distinct progenitors in vivo is not known. Using zebrafish, we found that motor neurons and oligodendrocytes are produced sequentially by distinct progenitors that have distinct origins. When olig2(+) cells were tracked during the peak period of motor neuron formation, most differentiated as motor neurons without further cell division. Using time-lapse imaging, we found that, as motor neurons differentiated, more dorsally positioned neuroepithelial progenitors descended to the pMN domain and initiated olig2 expression. Inhibition of Hedgehog signaling during motor neuron differentiation blocked the ventral movement of progenitors, the progressive initiation of olig2 expression, and oligodendrocyte formation. We therefore propose that the motor neuron-to-oligodendrocyte switch results from Hedgehog-mediated recruitment of glial-fated progenitors to the pMN domain subsequent to neurogenesis.
Hamilton, Nicola B; Clarke, Laura E; Arancibia-Carcamo, I Lorena;
Adjusting the thickness and internodal length of the myelin sheath is a mechanism for tuning the conduction velocity of axons to match computational needs. Interactions between oligodendrocyte precursor cells (OPCs) and developing axons regulate the formation of myelin around axons. We now show, ...
Maria Vittoria Simonini
Full Text Available In EAE (experimental autoimmune encephalomyelitis, agonists of PPARs (peroxisome proliferator-activated receptors provide clinical benefit and reduce damage. In contrast with PPARγ, agonists of PPARδ are more effective when given at later stages of EAE and increase myelin gene expression, suggesting effects on OL (oligodendrocyte maturation. In the present study we examined effects of the PPARδ agonist GW0742 on OPCs (OL progenitor cells, and tested whether the effects involve modulation of BMPs (bone morphogenetic proteins. We show that effects of GW0742 are mediated through PPARδ since no amelioration of EAE clinical scores was observed in PPARδ-null mice. In OPCs derived from E13 mice (where E is embryonic day, GW0742, but not the PPARγ agonist pioglitazone, increased the number of myelin-producing OLs. This was due to activation of PPARδ since process formation was reduced in PPARδ-null compared with wild-type OPCs. In both OPCs and enriched astrocyte cultures, GW0742 increased noggin protein expression; however, noggin mRNA was only increased in astrocytes. In contrast, GW0742 reduced BMP2 and BMP4 mRNA levels in OPCs, with lesser effects in astrocytes. These findings demonstrate that PPARδ plays a role in OPC maturation, mediated, in part, by regulation of BMP and BMP antagonists.
Jorge Oliver-De La Cruz
Full Text Available OBJECTIVES: A number of neurodegenerative diseases progress with a loss of myelin, which makes them candidate diseases for the development of cell-replacement therapies based on mobilisation or isolation of the endogenous neural/glial progenitor cells, in vitro expansion, and further implantation. Cells expressing A2B5 or PDGFRA/CNP have been isolated within the pool of glial progenitor cells in the subcortical white matter of the normal adult human brain, all of which demonstrate glial progenitor features. However, the heterogeneity and differentiation potential of this pool of cells is not yet well established. METHODS: We used diffusion tensor images, histopathology, and immunostaining analysis to demonstrate normal cytoarchitecture and the absence of abnormalities in human temporal lobe samples from patients with mesial temporal sclerosis. These samples were used to isolate and enrich glial progenitor cells in vitro, and later to detect such cells in vivo. RESULTS: We have identified a subpopulation of SOX2+ cells, most of them co-localising with OLIG2, in the white matter of the normal adult human brain in vivo. These cells can be isolated and enriched in vitro, where they proliferate and generate immature (O4+ and mature (MBP+ oligodendrocytes and, to a lesser extent, astrocytes (GFAP+. CONCLUSION: Our results demonstrate the existence of a new glial progenitor cell subpopulation that expresses SOX2 in the white matter of the normal adult human brain. These cells might be of use for tissue regeneration procedures.
Full Text Available Central nervous system injury induces a regenerative response in ensheathing glial cells comprising cell proliferation, spontaneous axonal remyelination, and limited functional recovery, but the molecular mechanisms are not fully understood. In Drosophila, this involves the genes prospero and Notch controlling the balance between glial proliferation and differentiation, and manipulating their levels in glia can switch the response to injury from prevention to promotion of repair. In the mouse, Notch1 maintains NG2 oligodendrocyte progenitor cells (OPCs in a progenitor state, but what factor may enable oligodendrocyte (OL differentiation and functional remyelination is not understood. Here, we asked whether the mammalian homologue of prospero, Prox1, is involved. Our data show that Prox1 is distributed in NG2+ OPCs and in OLs in primary cultured cells, and in the mouse spinal cord in vivo. siRNA prox1 knockdown in primary OPCs increased cell proliferation, increased NG2+ OPC cell number and decreased CC1+ OL number. Prox1 conditional knockout in the OL cell lineage in mice increased NG2+ OPC cell number, and decreased CC1+ OL number. Lysolecithin-induced demyelination injury caused a reduction in CC1+ OLs in homozygous Prox1-/- conditional knockout mice compared to controls. Remarkably, Prox1-/- conditional knockout mice had smaller lesions than controls. Altogether, these data show that Prox1 is required to inhibit OPC proliferation and for OL differentiation, and could be a relevant component of the regenerative glial response. Therapeutic uses of glia and stem cells to promote regeneration and repair after central nervous system injury would benefit from manipulating Prox1.
Objective: To investigate in vitro differentiation of oligodendrocyte precursor cells (OPCs) into mature oligodendrocytes in chemical conditional medium. Methods: The mixed glial cells from cerebral cortices of 48-hour-old Sprague-Dawley (SD) rats were cultured in vitro. The OPCs were separated by shaking procedure around 9-10 d in the primary culture. Then the isolated OPCs were further transferred into the chemical conditional medium for cell differentiation. The pattern of OPCs maturation in vitro was continuously observed with contrast phase microscopy and mature oligodendrocytes were further identified by immunocytochemical assays. Results: OPCs grew well when co-cultured with glial cells and distinct cellular stratification formed about 9-10 d in the primary culture, which indicated the appropriate opportunity for the separation of OPCs. Following cultured in the chemical conditional medium, the OPCs progressively differentiated into the mature oligodendrocytes. These mature oligodendrocytes were also immunostained with the oligodendrocyte lineage-specific antibody, Oligo2. Conclusion: The OPCs isolated from the cerebral cortices of neonatal SD rats can progressively differentiate into mature oligodendrocytes in the chemical conditional medium in vitro.
Vela, José M; Molina-Holgado, Eduardo; Arévalo-Martín, Angel; Almazán, Guillermina; Guaza, Carmen
Interleukin-1 (IL-1) is a pleiotropic cytokine expressed during normal CNS development and in inflammatory demyelinating diseases, but remarkably little is known about its effect on oligodendroglial cells. In this study we explored the role of IL-1beta in oligodendrocyte progenitors and differentiated oligodendrocytes. The effects of IL-1beta were compared to those of IL-1 receptor antagonist, the specific inhibitor of IL-1 activity, since progenitors and differentiated oligodendrocytes produce IL-1beta and express IL-1 receptors. Unlike other proinflammatory cytokines (TNFalpha and IFNgamma), IL-1beta was not toxic for oligodendrocyte lineage cells. However, this cytokine inhibited proliferation of oligodendrocyte progenitors in the presence of growth factors (PDGF plus bFGF). This was evidenced by a significant decrease in both cells incorporating bromodeoxyuridine (45%) and total cell numbers (57%) after 6 days of treatment. Interestingly, IL-1beta blocked proliferation at the late progenitor/prooligodendrocyte (O4+) stage but did not affect proliferation of early progenitors (A2B5+). Inhibition of proliferation paralleled with promotion of differentiation, as revealed by the increased percentage of R-mab+ cells (6.7-fold). Moreover, when oligodendrocyte progenitors were allowed to differentiate in the absence of growth factors, treatment with IL-1beta promoted maturation to the MBP+ stage (4.2-fold) and survival of differentiating oligodendrocytes (2.1-fold). Regarding intracellular signaling, IL-1beta activated the p38 mitogen-activated protein kinase (MAPK) but not the p42/p44 MAPK and, when combined with growth factors, intensified p38 activation but inhibited the growth-factor-induced p42/p44 activation. IL-1beta also induced a time-dependent inhibition of PFGF-Ralpha gene expression. These results support a role for IL-1beta in promoting mitotic arrest and differentiation of oligodendrocyte progenitors as well as maturation and survival of differentiating
Full Text Available Disrupted-in-schizophrenia 1 (DISC1 is a gene disrupted by a translocation, t(1;11 (q42.1;q14.3, that segregates with major psychiatric disorders, including schizophrenia, recurrent major depression and bipolar affective disorder, in a Scottish family. Here we report that mammalian DISC1 endogenously expressed in oligodendroglial lineage cells negatively regulates differentiation of oligodendrocyte precursor cells into oligodendrocytes. DISC1 expression was detected in oligodendrocytes of the mouse corpus callosum at P14 and P70. DISC1 mRNA was expressed in primary cultured rat cortical oligodendrocyte precursor cells and decreased when oligodendrocyte precursor cells were induced to differentiate by PDGF deprivation. Immunocytochemical analysis showed that overexpressed DISC1 was localized in the cell bodies and processes of oligodendrocyte precursor cells and oligodendrocytes. We show that expression of the myelin related markers, CNPase and MBP, as well as the number of cells with a matured oligodendrocyte morphology, were decreased following full length DISC1 overexpression. Conversely, both expression of CNPase and the number of oligodendrocytes with a mature morphology were increased following knockdown of endogenous DISC1 by RNA interference. Overexpression of a truncated form of DISC1 also resulted in an increase in expression of myelin related proteins and the number of mature oligodendrocytes, potentially acting via a dominant negative mechanism. We also identified involvement of Sox10 and Nkx2.2 in the DISC1 regulatory pathway of oligodendrocyte differentiation, both well-known transcription factors involved in the regulation of myelin genes.
Chen, Ying; Wu, Heng; Wang, Shuzong; Koito, Hisami; Li, Jianrong; Ye, Feng; Hoang, Jenny; Escobar, Sabine S; Gow, Alexander; Arnett, Heather A; Trapp, Bruce D; Karandikar, Nitin J; Hsieh, Jenny; Lu, Q Richard
The basic helix-loop-helix transcription factor Olig1 promotes oligodendrocyte maturation and is required for myelin repair. We characterized an Olig1-regulated G protein-coupled receptor, GPR17, whose function is to oppose the action of Olig1. Gpr17 was restricted to oligodendrocyte lineage cells, but was downregulated during the peak period of myelination and in adulthood. Transgenic mice with sustained Gpr17 expression in oligodendrocytes exhibited stereotypic features of myelinating disorders in the CNS. Gpr17 overexpression inhibited oligodendrocyte differentiation and maturation both in vivo and in vitro. Conversely, Gpr17 knockout mice showed early onset of oligodendrocyte myelination. The opposing action of Gpr17 on oligodendrocyte maturation reflects, at least partially, upregulation and nuclear translocation of the potent oligodendrocyte differentiation inhibitors ID2/4. Collectively, these findings suggest that GPR17 orchestrates the transition between immature and myelinating oligodendrocytes via an ID protein-mediated negative regulation and may serve as a potential therapeutic target for CNS myelin repair.
Moore, Craig S; Cui, Qiao-Ling; Warsi, Nebras M; Durafourt, Bryce A; Zorko, Nika; Owen, David R; Antel, Jack P; Bar-Or, Amit
In multiple sclerosis, successful remyelination within the injured CNS is largely dependent on the survival and differentiation of oligodendrocyte progenitor cells. During inflammatory injury, oligodendrocytes and oligodendrocyte progenitor cells within lesion sites are exposed to secreted products derived from both infiltrating immune cell subsets and CNS-resident cells. Such products may be considered either proinflammatory or anti-inflammatory and have the potential to contribute to both injury and repair processes. Within the CNS, astrocytes also contribute significantly to oligodendrocyte biology during development and following inflammatory injury. The overall objective of the current study was to determine how functionally distinct proinflammatory and anti-inflammatory human immune cell subsets, implicated in multiple sclerosis, can directly and/or indirectly (via astrocytes) impact human oligodendrocyte progenitor cell survival and differentiation. Proinflammatory T cell (Th1/Th17) and M1-polarized myeloid cell supernatants had a direct cytotoxic effect on human A2B5(+) neural progenitors, resulting in decreased O4(+) and GalC(+) oligodendrocyte lineage cells. Astrocyte-conditioned media collected from astrocytes pre-exposed to the same proinflammatory supernatants also resulted in decreased oligodendrocyte progenitor cell differentiation without an apparent increase in cell death and was mediated through astrocyte-derived CXCL10, yet this decrease in differentiation was not observed in the more differentiated oligodendrocytes. Th2 and M2 macrophage or microglia supernatants had neither a direct nor an indirect impact on oligodendrocyte progenitor cell differentiation. We conclude that proinflammatory immune cell responses can directly and indirectly (through astrocytes) impact the fate of immature oligodendrocyte-lineage cells, with oligodendrocyte progenitor cells more vulnerable to injury compared with mature oligodendrocytes.
Lee, Hyun Joon; Wu, Junfang; Chung, Jumi; Wrathall, Jean R
The upregulation of genes normally associated with development may occur in the adult after spinal cord injury (SCI). To test this, we performed real-time RT-PCR array analysis of mouse spinal cord mRNAs comparing embryonic day (E)14.5 spinal cord with intact adult and adult cord 1 week after a clinically relevant standardized contusion SCI. We found significantly increased expression of a large number of neural development- and stem cell-associated genes after SCI. These included Sox2 (sex determining region Y-box 2), a transcription factor that regulates self-renewal and potency of embryonic neural stem cells and is one of only a few key factors needed to induce pluripotency. In adult spinal cord of Sox2-EGFP mice, Sox2-EGFP was found mainly in the ependymal cells of the central canal. After SCI, both mRNA and protein levels of Sox2 were significantly increased at and near the injury site. By 1 day, Sox2 was upregulated in NG2(+) oligodendrocyte progenitor cells (OPC) in the spared white matter. By 3 days, Sox2-EGFP ependymal cells had increased proliferation and begun to form multiple layers and clusters of cells in the central lesion zone of the cord. Expression of Sox2 by NG2(+) cells had declined by 1 week, but increased numbers of other Sox2-expressing cells persisted for at least 4 weeks after SCI in both mouse and rat models. Thus, SCI upregulates many genes associated with development and neural stem cells, including the key transcription factor Sox2, which is expressed in a pool of cells that persists for weeks after SCI.
Butt, A M; Berry, M
The rat anterior medullary velum (AMV) is representative of the brain and spinal cord, overall, and provides an almost two-dimensional preparation for investigating axon-glial interactions in vivo. Here, we review some of our findings on axon-oligodendrocyte unit relations in our adult, development, and injury paradigms: (1) adult oligodendrocytes are phenotypically heterogeneous, conforming to Del Rio Hortega's types I-IV, whereby differences in oligodendrocyte morphology, metabolism, myelin sheath radial and longitudinal dimensions, and biochemistry correlate with the diameters of axons in the unit; (2) oligodendrocytes derive from a common premyelinating oligodendrocyte phenotype, and divergence of types I-IV is related to the age they emerge and the presumptive diameter of axons in the unit; (3) during myelination, axon-oligodendrocyte units progress through a sequence of maturation phases, related to axon contact, ensheathment, establishment of internodal myelin sheaths, and finally the radial growth and compaction of the myelin sheath; (4) we provide direct in vivo evidence that platelet-derived growth factor-AA (PDGF-AA), fibroblast growth factor (FGF-2), and insulin-like growth factor-I (IGF-I) differentially regulate these events, by injecting the growth factors into the cerebrospinal fluid of neonatal rat pups; (5) in lesioned adult AMV, transected central nervous system (CNS) axons regenerate through the putatively inhibitory environment of the glial scar, but remyelination by oligodendrocytes is incomplete, indicating that axon-oligodendrocyte interactions are defective; and (6) in the adult AMV, cells expressing the NG2 chondroitin sulphate have a presumptive adult oligodendrocyte progenitor antigenic phenotype, but are highly complex cells and send processes to contact axolemma at nodes of Ranvier, suggesting they subserve a specific perinodal function. Thus, axons and oligodendrocyte lineage cells form interdependent functional units, but
Ng, K P; Hu, Z; Ebrahem, Q; Negrotto, S; Lausen, J; Saunthararajah, Y
First-hits in the multi-hit process of leukemogenesis originate in germline or hematopoietic stem cells (HSCs), yet leukemia-initiating cells (LICs) usually have a lineage-committed phenotype. The molecular mechanisms underlying this compartment shift during leukemia evolution have not been a major focus of investigation and remain poorly understood. Here a mechanism underlying this shift was examined in the context of Runx1 deficiency, a frequent leukemia-initiating event. Lineage-negative cells isolated from the bone marrow of Runx1-haploinsufficient and wild-type control mice were cultured in granulocyte-colony-stimulating factor to force lineage commitment. Runx1-haploinsufficient cells demonstrated significantly greater and persistent exponential cell growth than wild-type controls. Not surprisingly, the Runx1-haploinsufficient cells were differentiation-impaired, by morphology and by flow-cytometric evaluation for granulocyte differentiation markers. Interestingly, however, this impaired differentiation was not because of decreased granulocyte lineage commitment, as RNA and protein upregulation of the master granulocyte lineage-commitment transcription factor Cebpa, and Hoxb4 repression, was similar in wild-type and Runx1-haploinsufficient cells. Instead, RNA and protein expression of Cebpe, a key driver of progressive maturation after lineage commitment, were significantly decreased in Runx1-haploinsufficient cells. Primary acute myeloid leukemia cells with normal cytogenetics and RUNX1 mutation also demonstrated this phenotype of very high CEBPA mRNA expression but paradoxically low expression of CEBPE, a CEBPA target gene. Chromatin-immunoprecipitation analyses suggested a molecular mechanism for this phenotype: in wild-type cells, Runx1 binding was substantially greater at the Cebpe than at the Cebpa enhancer. Furthermore, Runx1 deficiency substantially diminished high-level Runx1 binding at the Cebpe enhancer, but lower-level binding at the Cebpa
Saxon, Jacob G; Baer, Daniel R; Barton, Julie A; Hawkins, Travis; Wu, Bingruo; Trusk, Thomas C; Harris, Stephen E; Zhou, Bin; Mishina, Yuji; Sugi, Yukiko
Distal outgrowth, maturation and remodeling of the endocardial cushion mesenchyme in the atrioventricular (AV) canal are the essential morphogenetic events during four-chambered heart formation. Mesenchymalized AV endocardial cushions give rise to the AV valves and the membranous ventricular septum (VS). Failure of these processes results in several human congenital heart defects. Despite this clinical relevance, the mechanisms governing how mesenchymalized AV endocardial cushions mature and remodel into the membranous VS and AV valves have only begun to be elucidated. The role of BMP signaling in the myocardial and secondary heart forming lineage has been well studied; however, little is known about the role of BMP2 expression in the endocardial lineage. To fill this knowledge gap, we generated Bmp2 endocardial lineage-specific conditional knockouts (referred to as Bmp2 cKO(Endo)) by crossing conditionally-targeted Bmp2(flox/flox) mice with a Cre-driver line, Nfatc1(Cre), wherein Cre-mediated recombination was restricted to the endocardial cells and their mesenchymal progeny. Bmp2 cKO(Endo) mouse embryos did not exhibit failure or delay in the initial AV endocardial cushion formation at embryonic day (ED) 9.5-11.5; however, significant reductions in AV cushion size were detected in Bmp2 cKO(Endo) mouse embryos when compared to control embryos at ED13.5 and ED16.5. Moreover, deletion of Bmp2 from the endocardial lineage consistently resulted in membranous ventricular septal defects (VSDs), and mitral valve deficiencies, as evidenced by the absence of stratification of mitral valves at birth. Muscular VSDs were not found in Bmp2 cKO(Endo) mouse hearts. To understand the underlying morphogenetic mechanisms leading to a decrease in cushion size, cell proliferation and cell death were examined for AV endocardial cushions. Phospho-histone H3 analyses for cell proliferation and TUNEL assays for apoptotic cell death did not reveal significant differences between control
Xie, Di; Shen, Fengcai; He, Shaoru; Chen, Mengmeng; Han, Qianpeng; Fang, Ming; Zeng, Hongke; Chen, Chunbo; Deng, Yiyu
Neuroinflammation elicited by microglia plays a key role in periventricular white matter (PWM) damage (PWMD) induced by infectious exposure. This study aimed to determine if microglia-derived interleukin-1β (IL-1β) would induce hypomyelination through suppression of maturation of oligodendrocyte progenitor cells (OPCs) in the developing PWM. Sprague-Dawley rats (1-day old) were injected with lipopolysaccharide (LPS) (1 mg/kg) intraperitoneally, following which upregulated expression of IL-1β and IL-1 receptor 1 (IL-1R1 ) was observed. This was coupled with enhanced apoptosis and suppressed proliferation of OPCs in the PWM. The number of PDGFR-α and NG2-positive OPCs was significantly decreased in the PWM at 24 h and 3 days after injection of LPS, whereas it was increased at 14 days and 28 days. The protein expression of Olig1, Olig2, and Nkx2.2 was significantly reduced, and mRNA expression of Tcf4 and Axin2 was upregulated in the developing PWM after LPS injection. The expression of myelin basic protein (MBP) and 2',3'-cyclic-nucleotide 3"-phosphodiesterase (CNPase) was downregulated in the PWM at 14 days and 28 days after LPS injection; this was linked to reduction of the proportion of myelinated axons and thinner myelin sheath as revealed by electron microscopy. Primary cultured OPCs treated with IL-1β showed the failure of maturation and proliferation. Furthermore, FYN/MEK/ERK signaling pathway was involved in suppression of maturation of primary OPCs induced by IL-1β administration. Our results suggest that following LPS injection, microglia are activated and produce IL-1β in the PWM in the neonatal rats. Excess IL-1β inhibits the maturation of OPCs via suppression of FYN/MEK/ERK phosphorylation thereby leading to axonal hypomyelination.
Full Text Available Oligodendrocytes, the myelin-forming glial cells of the central nervous system (CNS, are fundamental players in rapid impulse conduction and normal axonal functions. JunB and c-Jun are DNA-binding components of the AP-1 transcription factor, which is known to regulate different processes such as proliferation, differentiation, stress responses and death in several cell types, including cultured oligodendrocyte/lineage cells. By selectively inactivating Jun B and c-Jun in myelinating oligodendrocytes in vivo, we generated mutant mice that developed normally, and within more than 12 months showed normal ageing and survival rates. In the adult CNS, absence of JunB and c-Jun from mature oligodendrocytes caused low-grade glial activation without overt signs of demyelination or secondary leukocyte infiltration into the brain. Even after exposure to toxic or autoimmune oligodendrocyte insults, signs of altered oligodendrocyte viability were mild and detectable only upon cuprizone treatment. We conclude that JunB and c-Jun expression in post-mitotic oligodendrocytes is mostly dispensable for the maintainance of white matter tracts throughout adult life, even under demyelinating conditions.
Girolamo, Francesco; Ferrara, Giovanni; Strippoli, Maurizio; Rizzi, Marco; Errede, Mariella; Trojano, Maria; Perris, Roberto; Roncali, Luisa; Svelto, Maria; Mennini, Tiziana; Virgintino, Daniela
Experimentally induced autoimmune encephalomyelitis (EAE) in mice provides an animal model that shares many features with human demyelinating diseases such as multiple sclerosis (MS). To what extent the cerebral cortex is affected by the process of demyelination and how the corollary response of the oligodendrocyte lineage is explicated are still not completely known aspects of EAE. By performing a detailed in situ analysis of expression of myelin and oligodendrocyte markers we have identified areas of subpial demyelination in the cerebral cortex of animals with conventionally induced EAE conditions. On EAE-affected cerebral cortices, the distribution and relative abundance of cells of the oligodendrocyte lineage were assessed and compared with control mouse brains. The analysis demonstrated that A2B5(+) glial restricted progenitors (GRPs) and NG2(+)/PDGFR-α(+) oligodendrocyte precursor cells (OPCs) were increased in number during "early" disease, 20 days post MOG immunization, whereas in the "late" disease, 39 days post-immunization, they were strongly diminished, and there was an accompanying reduction in NG2(+)/O4(+) pre-oligodendrocytes and GST-π mature oligodendrocytes. These results, together with the observed steady-state amount of NG2(-)/O4(+) pre-myelinating oligodendrocytes, suggested that oligodendroglial precursors attempted to compensate for the progressive loss of myelin, although these cells appeared to fail to complete the last step of their differentiation program. Our findings confirm that this chronic model of EAE reproduces the features of neocortex pathology in progressive MS and suggest that, despite the proliferative response of the oligodendroglial precursors, the failure to accomplish final differentiation may be a key contributing factor to the impaired remyelination that characterizes these demyelinating conditions. Copyright © 2011 Elsevier Inc. All rights reserved.
Zhang, Peilin; Chebath, Judith; Lonai, Peter; Revel, Michel
Embryonic stem (ES) cells derived from the inner cell mass of blastocyst-stage embryos are a potential large scale source of oligodendrocytes and of their progenitors for transplantation into the central nervous system for the repair of demyelinating lesions. We found previously that interleukin-6 (IL-6) fused to its soluble receptor (IL-6R), a potent activator of the gp130 receptor, induces myelin gene expression in Schwann cells of embryonic dorsal root ganglia. Like leukemia inhibitory factor, IL-6R/IL-6 inhibits the differentiation of murine ES cells into embryoid bodies. In the present study, we show that this recombinant cytokine may be efficiently used to stimulate the differentiation of oligodendrocytes if added to ES cell-derived neural precursors. IL-6R/IL-6 leads to an increase in early chondroitin sulfate proteoglycan positive and late O4 positive progenitors and to a stimulation of maturation into O1 and myelin basic protein expressing oligodendrocytes. Expression of the genes for transcription factor genes Olig-1 and Sox10, which appear early in the oligodendrocyte lineage, was stimulated by IL-6R/IL-6 addition. We conclude that this cytokine can significantly enhance the derivation of oligodendrocytes from ES cells.
Full Text Available There are numerous studies describing the signaling mechanisms that mediate oligodendrocyte precursor cell (OPC proliferation and differentiation, although the contribution of the cellular prion protein (PrP(c to this process remains unclear. PrP(c is a glycosyl-phosphatidylinositol (GPI-anchored glycoprotein involved in diverse cellular processes during the development and maturation of the mammalian central nervous system (CNS. Here we describe how PrP(c influences oligodendrocyte proliferation in the developing and adult CNS. OPCs that lack PrP(c proliferate more vigorously at the expense of a delay in differentiation, which correlates with changes in the expression of oligodendrocyte lineage markers. In addition, numerous NG2-positive cells were observed in cortical regions of adult PrP(c knockout mice, although no significant changes in myelination can be seen, probably due to the death of surplus cells.
Bresnahan Jacqueline C
Full Text Available Abstract Background Oligodendrocyte progenitor cells (OPCs and mature oligodendrocytes are both lost in central nervous system injury and disease. Activated microglia may play a role in OPC and oligodendrocyte loss or replacement, but it is not clear how the responses of OPCs and oligodendrocytes to activated microglia differ. Methods OPCs and microglia were isolated from rat cortex. OPCs were induced to differentiate into oligodendrocytes with thyroid hormone in defined medium. For selected experiments, microglia were added to OPC or oligodendrocyte cultures. Lipopolysaccharide was used to activate microglia and microglial activation was confirmed by TNFα ELISA. Cell survival was assessed with immunocytochemistry and cell counts. OPC proliferation and oligodendrocyte apoptosis were also assessed. Results OPCs and oligodendrocytes displayed phenotypes representative of immature and mature oligodendrocytes, respectively. Activated microglia reduced OPC survival, but increased survival and reduced apoptosis of mature oligodendrocytes. Activated microglia also underwent cell death themselves. Conclusion Activated microglia may have divergent effects on OPCs and mature oligodendrocytes, reducing OPC survival and increasing mature oligodendrocyte survival. This may be of importance because activated microglia are present in several disease states where both OPCs and mature oligodendrocytes are also reacting to injury. Activated microglia may simultaneously have deleterious and helpful effects on different cells after central nervous system injury.
Aileen Arriola; Mary E Kie; Yufang Shi; Randall D McKinnon
Dear Editor, We examined myelin formation by oligodendrocytes co-transplanted with immunosuppressive mesenchymal stem cells (MSCs). Oligodendrocyte precursor cells (OPCs) were grafted into the mouse retina, and graft survival and maturation was determined with or without adjunctive MSCs.
Ye, F.; Chen, Y.; Hoang, T.; Montgomery, R.L.; Zhao, X.H.; Bu, H.; Hu, T.; Taketo, M.M.; van Es, J.H.; Clevers, H.; Hsieh, J.; Bassel-Duby, R.; Olson, E.N.; Lu, Q.R.
Oligodendrocyte development is regulated by the interaction of repressors and activators in a complex transcriptional network. We found that two histone-modifying enzymes, HDAC1 and HDAC2, were required for oligodendrocyte formation. Genetic deletion of both Hdac1 and Hdac2 in oligodendrocyte lineag
Ng, K. P.; Hu, Z.; Ebrahem, Q; Negrotto, S; Lausen, J.; Saunthararajah, Y
First-hits in the multi-hit process of leukemogenesis originate in germline or hematopoietic stem cells (HSCs), yet leukemia-initiating cells (LICs) usually have a lineage-committed phenotype. The molecular mechanisms underlying this compartment shift during leukemia evolution have not been a major focus of investigation and remain poorly understood. Here a mechanism underlying this shift was examined in the context of Runx1 deficiency, a frequent leukemia-initiating event. Lineage-negative c...
Nishikawa, Yumiko; Nishijima, Hitoshi; Matsumoto, Minoru; Morimoto, Junko; Hirota, Fumiko; Takahashi, Satoru; Luche, Hervé; Fehling, Hans Joerg; Mouri, Yasuhiro; Matsumoto, Mitsuru
Understanding the cellular dynamics of Aire-expressing lineage(s) among medullary thymic epithelial cells (AEL-mTECs) is essential for gaining insight into the roles of Aire in establishment of self-tolerance. In this study, we monitored the maturation program of AEL-mTECs by temporal lineage tracing, in which bacterial artificial chromosome transgenic mice expressing tamoxifen-inducible Cre recombinase under control of the Aire regulatory element were crossed with reporter strains. We estimated that the half-life of AEL-mTECs subsequent to Aire expression was ∼7-8 d, which was much longer than that reported previously, owing to the existence of a post-Aire stage. We found that loss of Aire did not alter the overall lifespan of AEL-mTECs, inconsistent with the previous notion that Aire expression in medullary thymic epithelial cells (mTECs) might result in their apoptosis for efficient cross-presentation of self-antigens expressed by AEL-mTECs. In contrast, Aire was required for the full maturation program of AEL-mTECs, as exemplified by the lack of physiological downregulation of CD80 during the post-Aire stage in Aire-deficient mice, thus accounting for the abnormally increased CD80(high) mTECs seen in such mice. Of interest, increased CD80(high) mTECs in Aire-deficient mice were not mTEC autonomous and were dependent on cross-talk with thymocytes. These results further support the roles of Aire in the differentiation program of AEL-mTECs.
Full Text Available Mesenchymal stem cells (MSCs are viewed as safe, readily available and promising adult stem cells, which are currently used in several clinical trials. Additionally, their soluble-factor secretion and multi-lineage differentiation capacities place MSCs in the forefront of stem cell types with expected near-future clinical applications. In the present work MSCs were isolated from the umbilical cord matrix (Wharton's jelly of human umbilical cord samples. The cells were thoroughly characterized and confirmed as bona-fide MSCs, presenting in vitro low generation time, high proliferative and colony-forming unit-fibroblast (CFU-F capacity, typical MSC immunophenotype and osteogenic, chondrogenic and adipogenic differentiation capacity. The cells were additionally subjected to an oligodendroglial-oriented step-wise differentiation protocol in order to test their neural- and oligodendroglial-like differentiation capacity. The results confirmed the neural-like plasticity of MSCs, and suggested that the cells presented an oligodendroglial-like phenotype throughout the differentiation protocol, in several aspects sharing characteristics common to those of bona-fide oligodendrocyte precursor cells and differentiated oligodendrocytes.
Boulanger, Jenna J.; Messier, Claude
Key Points Oligodendrocyte precursor cells express doublecortin, a microtubule-associated protein.Oligodendrocyte precursor cells express doublecortin, but at a lower level of expression than in neuronal precursor.Doublecortin is not associated with a potential immature neuronal phenotype in Oligodendrocyte precursor cells. Oligodendrocyte precursor cells (OPC) are glial cells that differentiate into myelinating oligodendrocytes during embryogenesis and early stages of post-natal life. OPCs continue to divide throughout adulthood and some eventually differentiate into oligodendrocytes in response to demyelinating lesions. There is growing evidence that OPCs are also involved in activity-driven de novo myelination of previously unmyelinated axons and myelin remodeling in adulthood. Considering these roles in the adult brain, OPCs are likely mobile cells that can migrate on some distances before they differentiate into myelinating oligodendrocytes. A number of studies have noted that OPCs express doublecortin (DCX), a microtubule-associated protein expressed in neural precursor cells and in migrating immature neurons. Here we describe the distribution of DCX in OPCs. We found that almost all OPCs express DCX, but the level of expression appears to be much lower than what is found in neural precursor. We found that DCX is downregulated when OPCs start expressing mature oligodendrocyte markers and is absent in myelinating oligodendrocytes. DCX does not appear to signal an immature neuronal phenotype in OPCs in the adult mouse brain. Rather, it could be involved either in cell migration, or as a marker of an immature oligodendroglial cell phenotype.
Full Text Available Oligodendrocytes are the myelinating cells of the central nervous system (CNS. While the phrase is oft repeated and holds true, the last few years have borne witness to radical change in our understanding of this unique cell type. Once considered static glue, oligodendrocytes are now seen as plastic and adaptive, capable of reacting to a changing CNS. This review is intended as a primer and guide, exploring how the past five years have fundamentally altered our appreciation of oligodendrocyte development and CNS myelination.
Michalski, John-Paul; Kothary, Rashmi
Oligodendrocytes are the myelinating cells of the central nervous system (CNS). While the phrase is oft repeated and holds true, the last few years have borne witness to radical change in our understanding of this unique cell type. Once considered static glue, oligodendrocytes are now seen as plastic and adaptive, capable of reacting to a changing CNS. This review is intended as a primer and guide, exploring how the past 5 years have fundamentally altered our appreciation of oligodendrocyte development and CNS myelination.
Maki, Takakuni; Takahashi, Yoko; Miyamoto, Nobukazu; Liang, Anna C; Ihara, Masafumi; Lo, Eng H; Arai, Ken
Oligodendrocytes, which are the main cell type in cerebral white matter, are generated from their precursor cells (oligodendrocyte precursor cells: OPCs). However, the differentiation from OPCs to oligodendrocytes is disturbed under stressed conditions. Therefore, drugs that can improve oligodendrocyte regeneration may be effective for white matter-related diseases. Here we show that a vasoactive peptide adrenomedullin (AM) promotes the in vitro differentiation of OPCs under pathological conditions. Primary OPCs were prepared from neonatal rat brains, and differentiated into myelin-basic-protein expressing oligodendrocytes over time. This in vitro OPC differentiation was inhibited by prolonged chemical hypoxic stress induced by non-lethal CoCl(2) treatment. However, AM promoted the OPC differentiation under the hypoxic stress conditions, and the AM receptor antagonist AM(22-52) canceled the AM-induced OPC differentiation. In addition, AM treatment increased the phosphorylation level of Akt in OPC cultures, and correspondingly, the PI3K/Akt inhibitor LY294002 blocked the AM-induced OPC differentiation. Taken together, AM treatment rescued OPC maturation under pathological conditions via an AM-receptor-PI3K/Akt pathway. Oligodendrocytes play critical roles in white matter by forming myelin sheath. Therefore, AM signaling may be a promising therapeutic target to boost oligodendrocyte regeneration in CNS disorders.
Sperber, B R; McMorris, F A
The non-receptor protein tyrosine kinase Fyn, which is a member of the Src family of kinases, has been shown to be essential for normal myelination and has been suggested to play a role in oligodendrocyte development. However, oligodendrocyte development has not been studied directly in cells lacking Fyn. Additionally, because Fyn is expressed in neurons as well as oligodendrocytes, it is possible that normal myelination requires Fyn expression in neurons but not in oligodendrocytes. To address these issues, we analyzed the development of oligodendrocytes in neuron-free glial cell cultures from fyn(-/-) mice that express no Fyn protein. We observed that oligodendrocytes develop to the stage where they elaborate an extensive network of membranous processes and express the antigenic components of mature oligodendrocytes in the complete absence of Fyn. However, as compared with fyn(+/+) controls, fewer oligodendroglia developed in fyn(-/-) cell cultures, and a smaller proportion of them matured to the stage characterized by a high degree of morphological complexity. In addition, we found that insulin-like growth factor-I, a potent stimulator of oligodendrocyte development, failed to stimulate morphological maturation of fyn(-/-) oligodendroglia. The pyrazolopyrimidine PP2, believed to be a selective inhibitor of Fyn, did not prevent the development of morphologically complex oligodendrocytes. Unexpectedly, however, it was toxic to both fyn(+/+) and fyn(-/-) glial cells, indicating that this class of inhibitors can have significant effects that are independent of Fyn.
Brian S Letzen
Full Text Available BACKGROUND: Cells of the oligodendrocyte (OL lineage play a vital role in the production and maintenance of myelin, a multilamellar membrane which allows for saltatory conduction along axons. These cells may provide immense therapeutic potential for lost sensory and motor function in demyelinating conditions, such as spinal cord injury, multiple sclerosis, and transverse myelitis. However, the molecular mechanisms controlling OL differentiation are largely unknown. MicroRNAs (miRNAs are considered the "micromanagers" of gene expression with suggestive roles in cellular differentiation and maintenance. Although unique patterns of miRNA expression in various cell lineages have been characterized, this is the first report documenting their expression during oligodendrocyte maturation from human embryonic stem (hES cells. Here, we performed a global miRNA analysis to reveal and identify characteristic patterns in the multiple stages leading to OL maturation from hES cells including those targeting factors involved in myelin production. METHODOLOGY/PRINCIPAL FINDINGS: We isolated cells from 8 stages of OL differentiation. Total RNA was subjected to miRNA profiling and validations preformed using real-time qRT-PCR. A comparison of miRNAs from our cultured OLs and OL progenitors showed significant similarities with published results from equivalent cells found in the rat and mouse central nervous system. Principal component analysis revealed four main clusters of miRNA expression corresponding to early, mid, and late progenitors, and mature OLs. These results were supported by correlation analyses between adjacent stages. Interestingly, the highest differentially-expressed miRNAs demonstrated a similar pattern of expression throughout all stages of differentiation, suggesting that they potentially regulate a common target or set of targets in this process. The predicted targets of these miRNAs include those with known or suspected roles in
Wang, Yanlin; Zhang, Yanbo; He, Jue; Zhang, Handi; Xiao, Lan; Nazarali, Adil; Zhang, Zhijun; Zhang, Dai; Tan, Qingrong; Kong, Jiming; Li, Xin-Min
St. John's wort has been found to be an effective and safe herbal treatment for depression in several clinical trials. However, the underlying mechanism of its therapeutic effects is unclear. Recent studies show that the loss and malfunction of oligodendrocytes are closely related to the neuropathological changes in depression, which can be reversed by antidepressant treatment. In this study, we evaluated the effects of hyperforin, a major active component of St. John's wort, on the proliferation, development and mitochondrial function of oligodendrocytes. The study results revealed that hyperforin promotes maturation of oligodendrocytes and increases mitochondrial function without affecting proliferation of an oligodendrocyte progenitor cell line and neural stem/progenitor cells. Hyperforin also prevented mitochondrial toxin-induced cytotoxicity in an oligodendrocyte progenitor cell line. These findings suggest that hyperforin may stimulate the development and function of oligodendrocytes, which could be a mechanism of its effect in depression. Future in vitro and in vivo studies are required to further characterize the mechanisms of hyperforin.
Gupta, Aparna; Wodziak, Dariusz; Tun, May; Bouley, Donna M.; Lowe, Anson W.
Recent studies of epithelial tissues have revealed the presence of tissue-specific stem cells that are able to establish multiple cell lineages within an organ. The stem cells give rise to progenitors that replicate before differentiating into specific cell lineages. The mechanism by which homeostasis is established between proliferating stem or progenitor cells and terminally differentiated cells is unclear. This study demonstrates that Agr2 expression by mucous neck cells in the stomach promotes the differentiation of multiple cell lineages while also inhibiting the proliferation of stem or progenitor cells. When Agr2 expression is absent, gastric mucous neck cells increased in number as does the number of proliferating cells. Agr2 expression loss also resulted in the decline of terminally differentiated cells, which was supplanted by cells that exhibited nuclear SOX9 labeling. Sox9 expression has been associated with progenitor and stem cells. Similar effects of the Agr2 null on cell proliferation in the intestine were also observed. Agr2 consequently serves to maintain the balance between proliferating and differentiated epithelial cells. PMID:23209296
Czepiel, Marcin; Boddeke, Erik; Copray, Sjef
Studies on myelination and oligodendrocyte development are inevitably linked with demyelinating conditions such as multiple sclerosis (MS), leukodystrophies or spinal cord injury (SCI). Chronic loss of myelin, subsequently leading to neurodegeneration, is the ultimate cause of severe and permanent d
Goldman, Steven A.; Kuypers, Nicholas J.
and cerebral palsy, to multiple sclerosis and white matter stroke. Accordingly, replacing lost oligodendrocytes, whether by transplanting oligodendrocyte progenitor cells (OPCs) or by mobilizing endogenous progenitors, holds great promise as a therapeutic strategy for the diseases of central white matter....... In this Primer, we describe the molecular events regulating oligodendrocyte development and how our understanding of this process has led to the establishment of methods for producing OPCs and oligodendrocytes from embryonic stem cells and induced pluripotent stem cells, as well as directly from somatic cells....... In addition, we will discuss the safety of engrafted stem cell-derived OPCs, as well as approaches by which to modulate their differentiation and myelinogenesis in vivo following transplantation....
Srivastava, Rupali; Kumar, Manoj; Peineau, Stéphane; Csaba, Zsolt; Mani, Shyamala; Gressens, Pierre; El Ghouzzi, Vincent
Directing differentiation of embryonic stem cells (ESCs) to specific neuronal subtype is critical for modeling disease pathology in vitro. An attractive means of action would be to combine regulatory differentiation factors and extrinsic inductive signals added to the culture medium. In this study, we have generated mature cerebellar granule neurons by combining a temporally controlled transient expression of Math1, a master gene in granule neuron differentiation, with inductive extrinsic factors involved in cerebellar development. Using a Tetracyclin-On transactivation system, we overexpressed Math1 at various stages of ESCs differentiation and found that the yield of progenitors was considerably increased when Math1 was induced during embryonic body stage. Math1 triggered expression of Mbh1 and Mbh2, two target genes directly involved in granule neuron precursor formation and strong expression of early cerebellar territory markers En1 and NeuroD1. Three weeks after induction, we observed a decrease in the number of glial cells and an increase in that of neurons albeit still immature. Combining Math1 induction with extrinsic factors specifically increased the number of neurons that expressed Pde1c, Zic1, and GABAα6R characteristic of mature granule neurons, formed "T-shaped" axons typical of granule neurons, and generated synaptic contacts and action potentials in vitro. Finally, in vivo implantation of Math1-induced progenitors into young adult mice resulted in cell migration and settling of newly generated neurons in the cerebellum. These results show that conditional induction of Math1 drives ESCs toward the cerebellar fate and indicate that acting on both intrinsic and extrinsic factors is a powerful means to modulate ESCs differentiation and maturation into a specific neuronal lineage.
Relucio, Jenne; Menezes, Michael J; Miyagoe-Suzuki, Yuko; Takeda, Shin'ichi; Colognato, Holly
The laminin family of extracellular matrix proteins are expressed broadly during embryonic brain development, but are enriched at ventricular and pial surfaces where laminins mediate radial glial attachment during corticogenesis. In the adult brain, however, laminin distribution is restricted, yet is found within the vascular basal lamina and associated fractones of the ventricular zone (VZ)-subventricular zone (SVZ) stem cell niche, where laminins regulate adult neural progenitor cell proliferation. It remains unknown, however, if laminins regulate the wave of oligodendrogenesis that occurs in the neonatal/early postnatal VZ-SVZ. Here we report that Lama2, the gene that encodes the laminin α2-subunit, regulates postnatal oligodendrogenesis. At birth, Lama2-/- mice had significantly higher levels of dying oligodendrocyte progenitor cells (OPCs) in the OPC germinal zone of the dorsal SVZ. This translated into fewer OPCs, both in the dorsal SVZ well as in an adjacent developing white matter tract, the corpus callosum. In addition, intermediate progenitor cells that give rise to OPCs in the Lama2-/- VZ-SVZ were mislocalized and proliferated nearer to the ventricle surface. Later, delays in oligodendrocyte maturation (with accompanying OPC accumulation), were observed in the Lama2-/- corpus callosum, leading to dysmyelination by postnatal day 21. Together these data suggest that prosurvival laminin interactions in the developing postnatal VZ-SVZ germinal zone regulate the ability, or timing, of oligodendrocyte production to occur appropriately.
Full Text Available Pluripotent stem cells provide an invaluable tool for generating human, disease-relevant cells. Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system, characterized by myelin damage. Oligodendrocytes are the myelinating cells of the central nervous system (CNS; they differentiate from progenitor cells, and their membranes ensheath axons, providing trophic support and allowing fast conduction velocity. The current understanding of oligodendrocyte biology was founded by rodent studies, where the establishment of repressive epigenetic marks on histone proteins, followed by activation of myelin genes, leads to lineage progression. To assess whether this epigenetic regulation is conserved across species, we differentiated human embryonic and induced pluripotent stem cells to oligodendrocytes and asked whether similar histone marks and relative enzymatic activities could be detected. The transcriptional levels of enzymes responsible for methylation and acetylation of histone marks were analyzed during oligodendrocyte differentiation, and the post-translational modifications on histones were detected using immunofluorescence. These studies showed that also in human cells, differentiation along the oligodendrocyte lineage is characterized by the acquisition of multiple repressive histone marks, including deacetylation of lysine residues on histone H3 and trimethylation of residues K9 and K27. These data suggest that the epigenetic modulation of oligodendrocyte identity is highly conserved across species.
Dach, Katharina; Bendt, Farina; Huebenthal, Ulrike; Giersiefer, Susanne; Lein, Pamela J; Heuer, Heike; Fritsche, Ellen
Polybrominated diphenyl ethers (PBDEs) are bioaccumulating flame retardants causing developmental neurotoxicity (DNT) in humans and rodents. Their DNT effects are suspected to involve thyroid hormone (TH) signaling disruption. Here, we tested the hypothesis whether disturbance of neural progenitor cell (NPC) differentiation into the oligodendrocyte lineage (O4(+) cells) by BDE-99 involves disruption of TH action in human and mouse (h,m)NPCs. Therefore, we quantified differentiation of NPCs into O4(+) cells and measured their maturation via expression of myelin-associated genes (hMBP, mMog) in presence and absence of TH and/or BDE-99. T3 promoted O4(+) cell differentiation in mouse, but not hNPCs, and induced hMBP/mMog gene expression in both species. BDE-99 reduced generation of human and mouse O4(+) cells, but there is no indication for BDE-99 interfering with cellular TH signaling during O4(+) cell formation. BDE-99 reduced hMBP expression due to oligodendrocyte reduction, but concentrations that did not affect the number of mouse O4(+) cells inhibited TH-induced mMog transcription by a yet unknown mechanism. In addition, ascorbic acid antagonized only the BDE-99-dependent loss of human, not mouse, O4(+) cells by a mechanism probably independent of reactive oxygen species. These data point to species-specific modes of action of BDE-99 on h/mNPC development into the oligodendrocyte lineage.
Mitew, S; Hay, C M; Peckham, H; Xiao, J; Koenning, M; Emery, B
Oligodendrocytes and the myelin they produce are a remarkable vertebrate specialization that enables rapid and efficient nerve conduction within the central nervous system. The generation of myelin during development involves a finely-tuned pathway of oligodendrocyte precursor specification, proliferation and migration followed by differentiation and the subsequent myelination of appropriate axons. In this review we summarize the molecular mechanisms known to regulate each of these processes, including the extracellular ligands that promote or inhibit development of the oligodendrocyte lineage, the intracellular pathways they signal through and the key transcription factors that mediate their effects. Many of these regulatory mechanisms have recurring roles in regulating several transitions during oligodendrocyte development, highlighting their importance. It is also highly likely that many of these developmental mechanisms will also be involved in myelin repair in human neurological disease.
Full Text Available OBJECTIVE: To investigate the effects of melatonin treatment in a rat model of white matter damage (WMD in the developing brain. Additionally, we aim to delineate the cellular mechanisms of melatonin effect on the oligodendroglial cell lineage. METHODS: A unilateral ligation of the uterine artery in pregnant rat at the embryonic day 17 induces fetal hypoxia and subsequent growth restriction (GR in neonatal pups. GR and control pups received a daily intra-peritoneal injection of melatonin from birth to post-natal day (P 3. RESULTS: Melatonin administration was associated with a dramatic decrease in microglial activation and astroglial reaction compared to untreated GR pups. At P14, melatonin prevented white matter myelination defects with an increased number of mature oligodendrocytes (APC-immunoreactive in treated GR pups. Conversely, melatonin was not found to be associated with an increased density of total oligodendrocytes (Olig2-immunoreactive, suggesting that melatonin is able to promote oligodendrocyte maturation but not proliferation. These effects appear to be melatonin-receptor dependent and were reproduced in vitro. INTERPRETATION: These data suggest that melatonin has a strong protective effect on developing damaged white matter through decreased microglial activation and oligodendroglial maturation leading to a normalization of the myelination process. Consequently, melatonin should be a considered as an effective neuroprotective candidate not only in perinatal brain damage but also in inflammatory and demyelinating diseases observed in adults.
Cavaliere, F; Urra, O; Alberdi, E; Matute, C
We used multipotent stem cells (MSCs) derived from the young rat subventricular zone (SVZ) to study the effects of glutamate in oligodendrocyte maturation. Glutamate stimulated oligodendrocyte differentiation from SVZ-derived MSCs through the activation of specific N-methyl-D-aspartate (NMDA) receptor subunits. The effect of glutamate and NMDA on oligodendrocyte differentiation was evident in both the number of newly generated oligodendrocytes and their morphology. In addition, the levels of NMDAR1 and NMDAR2A protein increased during differentiation, whereas NMDAR2B and NMDAR3 protein levels decreased, suggesting differential expression of NMDA receptor subunits during maturation. Microfluorimetry showed that the activation of NMDA receptors during oligodendrocyte differentiation elevated cytosolic calcium levels and promoted myelination in cocultures with neurons. Moreover, we observed that stimulation of MSCs by NMDA receptors induced the generation of reactive oxygen species (ROS), which were negatively modulated by the NADPH inhibitor apocynin, and that the levels of ROS correlated with the degree of differentiation. Taken together, these findings suggest that ROS generated by NADPH oxidase by the activation of NMDA receptors promotes the maturation of oligodendrocytes and favors myelination.
DeAizpurua, H J; Cram, D S; Naselli, G; Devereux, L; Dorow, D S
Events controlling differentiation to insulin-secreting beta-cells in the pancreas are not well understood, although beta-cells are thought to arise from pluripotent ductal precursor cells. To search for signaling proteins that might be involved in beta-cell maturation, we analyzed protein kinase expression in two developmentally and functionally distinct pancreatic beta-cell lines, RIN-5AH and RIN-A12, by reverse transcriptase polymerase chain reaction. A number of tyrosine and serine/threonine kinases were identified in both lines. One protein kinase, mixed lineage kinase-1 (MLK-1), was expressed at both the RNA and protein levels in RIN-5AH cells, which display an immature beta-cell phenotype, but was not detected in the more mature RIN-A12 cells. Furthermore, levels of MLK-1 mRNA and protein were increased after brief stimulation of RIN-5AH cells with either the differentiation inducer, sodium butyrate, or with serum after serum starvation. These increases in expression were independent of phenotypic markers such as insulin secretion or surface expression of major histocompatibility class I- and A2B5-reactive ganglioside. In addition, increases in MLK-1 expression in the stimulated RIN-5AH cells were accompanied by phosphorylation of MLK-1 on serine but not tyrosine. Antisense oligonucleotides to two distinct regions of MLK-1 caused RIN-5AH cells, but not RIN-A12 cells, to adopt a highly undifferentiated morphology, with a reduction in DNA synthesis and MLK-1 protein levels and elevated glucagon mRNA levels, but with no effect on insulin mRNA. In an immunohistochemical survey of embryonic mouse tissues, we found that temporal expression of MLK-1 was regulated in a tissue-specific manner. In the embryonic pancreas, MLK-1 expression was evident in ductal cells from day 13 to 16 but was not detected in late stage gestation or neonatal pancreas. These data suggest that MLK-1 is regulated in immature pancreatic beta-cells and their ductal precursors at the level of
Full Text Available BACKGROUND: This study aims to differentiate human induced pluripotent stem cells (hiPSCs into oligodendrocyte precursors and assess their recovery potential in a demyelinated optic chiasm model in rats. METHODOLOGY/PRINCIPAL FINDINGS: We generated a cell population of oligodendrocyte progenitors from hiPSCs by using embryoid body formation in a defined medium supplemented with a combination of factors, positive selection and mechanical enrichment. Real-time polymerase chain reaction and immunofluorescence analyses showed that stage-specific markers, Olig2, Sox10, NG2, PDGFRα, O4, A2B5, GalC, and MBP were expressed following the differentiation procedure, and enrichment of the oligodendrocyte lineage. These results are comparable with the expression of stage-specific markers in human embryonic stem cell-derived oligodendrocyte lineage cells. Transplantation of hiPSC-derived oligodendrocyte progenitors into the lysolecithin-induced demyelinated optic chiasm of the rat model resulted in recovery from symptoms, and integration and differentiation into oligodendrocytes were detected by immunohistofluorescence staining against PLP and MBP, and measurements of the visual evoked potentials. CONCLUSIONS/SIGNIFICANCE: These results showed that oligodendrocyte progenitors generated efficiently from hiPSCs can be used in future biomedical studies once safety issues have been overcome.
Wrzos, Claudia; Winkler, Anne; Metz, Imke; Kayser, Dieter M; Thal, Dietmar R; Wegner, Christiane; Brück, Wolfgang; Nessler, Stefan; Bennett, Jeffrey L; Stadelmann, Christine
Neuromyelitis optica (NMO) is a chronic, mostly relapsing inflammatory demyelinating disease of the CNS characterized by serum anti-aquaporin 4 (AQP4) antibodies in the majority of patients. Anti-AQP4 antibodies derived from NMO patients target and deplete astrocytes in experimental models when co-injected with complement. However, the time course and mechanisms of oligodendrocyte loss and demyelination and the fate of oligodendrocyte precursor cells (OPC) have not been examined in detail. Also, no studies regarding astrocyte repopulation of experimental NMO lesions have been reported. We utilized two rat models using either systemic transfer or focal intracerebral injection of recombinant human anti-AQP4 antibodies to generate NMO-like lesions. Time-course experiments were performed to examine oligodendroglial and astroglial damage and repair. In addition, oligodendrocyte pathology was studied in early human NMO lesions. Apart from early complement-mediated astrocyte destruction, we observed a prominent, very early loss of oligodendrocytes and oligodendrocyte precursor cells (OPCs) as well as a delayed loss of myelin. Astrocyte repopulation of focal NMO lesions was already substantial after 1 week. Olig2-positive OPCs reappeared before NogoA-positive, mature oligodendrocytes. Thus, using two experimental models that closely mimic the human disease, our study demonstrates that oligodendrocyte and OPC loss is an extremely early feature in the formation of human and experimental NMO lesions and leads to subsequent, delayed demyelination, highlighting an important difference in the pathogenesis of MS and NMO.
Meraviglia, Veronica; Ulivi, Alessandro Francesco; Boccazzi, Marta; Valenza, Fabiola; Fratangeli, Alessandra; Passafaro, Maria; Lecca, Davide; Stagni, Fiorenza; Giacomini, Andrea; Bartesaghi, Renata; Abbracchio, Maria P; Ceruti, Stefania; Rosa, Patrizia
The G protein-coupled receptor 17 (GPR17) plays crucial roles in myelination. It is highly expressed during transition of oligodendrocyte progenitor cells to immature oligodendrocytes, but, after this stage, it must be down-regulated to allow generation of mature myelinating cells. After endocytosis, GPR17 is sorted into lysosomes for degradation or recycled to the plasma membrane. Balance between degradation and recycling is important for modulation of receptor levels at the cell surface and thus for the silencing/activation of GPR17-signaling pathways that, in turn, affect oligodendrocyte differentiation. The molecular mechanisms at the basis of these processes are still partially unknown and their characterization will allow a better understanding of myelination and provide cues to interpret the consequences of GPR17 dysfunction in diseases. Here, we demonstrate that the endocytic trafficking of GPR17 is mediated by the interaction of a type I PDZ-binding motif located at the C-terminus of the receptor and SNX27, a recently identified protein of the endosome-associated retromer complex and whose functions in oligodendrocytes have never been studied. SNX27 knock-down significantly reduces GPR17 plasma membrane recycling in differentiating oligodendrocytes while accelerating cells' terminal maturation. Interestingly, trisomy-linked down-regulation of SNX27 expression in the brain of Ts65Dn mice, a model of Down syndrome, correlates with a decrease in GPR17(+) cells and an increase in mature oligodendrocytes, which, however, fail in reaching full maturation, eventually leading to hypomyelination. Our data demonstrate that SNX27 modulates GPR17 plasma membrane recycling and stability, and that disruption of the SNX27/GPR17 interaction might contribute to pathological oligodendrocyte differentiation defects. GLIA 2016. GLIA 2016;64:1437-1460.
Alerie Guzman De La Fuente
Full Text Available The role of the neurovascular niche in CNS myelin regeneration is incompletely understood. Here, we show that, upon demyelination, CNS-resident pericytes (PCs proliferate, and parenchymal non-vessel-associated PC-like cells (PLCs rapidly develop. During remyelination, mature oligodendrocytes were found in close proximity to PCs. In Pdgfbret/ret mice, which have reduced PC numbers, oligodendrocyte progenitor cell (OPC differentiation was delayed, although remyelination proceeded to completion. PC-conditioned medium accelerated and enhanced OPC differentiation in vitro and increased the rate of remyelination in an ex vivo cerebellar slice model of demyelination. We identified Lama2 as a PC-derived factor that promotes OPC differentiation. Thus, the functional role of PCs is not restricted to vascular homeostasis but includes the modulation of adult CNS progenitor cells involved in regeneration.
Jamie L. Lim
Full Text Available Oligodendrocyte damage and loss are key features of multiple sclerosis (MS pathology. Oligodendrocytes appear to be particularly vulnerable to reactive oxygen species (ROS and cytokines, such as tumor necrosis factor-α (TNF, which induce cell death and prevent the differentiation of oligodendrocyte progenitor cells (OPCs. Here, we investigated the efficacy of sulforaphane (SFN, monomethyl fumarate (MMF and Protandim to induce Nrf2-regulated antioxidant enzyme expression, and protect oligodendrocytes against ROS-induced cell death and ROS-and TNF-mediated inhibition of OPC differentiation. OLN-93 cells and primary rat oligodendrocytes were treated with SFN, MMF or Protandim resulting in significant induction of Nrf2-driven (antioxidant proteins heme oygenase-1, nicotinamide adenine dinucleotide phosphate (NADPH: quinone oxidoreductase-1 and p62/SQSTM1, as analysed by Western blotting. After incubation with the compounds, oligodendrocytes were exposed to hydrogen peroxide. Protandim most potently promoted oligodendrocyte cell survival as measured by live/death viability assay. Moreover, OPCs were treated with Protandim or vehicle control prior to exposing them to TNF or hydrogen peroxide for five days, which inhibited OPC differentiation. Protandim significantly promoted OPC differentiation under influence of ROS, but not TNF. Protandim, a combination of five herbal ingredients, potently induces antioxidants in oligodendrocytes and is able to protect oligodendrocytes against oxidative stress by preventing ROS-induced cell death and promoting OPC differentiation.
Gobert, Rosanna Pescini; Joubert, Lara; Curchod, Marie-Laure; Salvat, Catherine; Foucault, Isabelle; Jorand-Lebrun, Catherine; Lamarine, Marc; Peixoto, Hélène; Vignaud, Chloé; Frémaux, Christèle; Jomotte, Thérèse; Françon, Bernard; Alliod, Chantal; Bernasconi, Lilia; Abderrahim, Hadi; Perrin, Dominique; Bombrun, Agnes; Zanoguera, Francisca; Rommel, Christian; Hooft van Huijsduijnen, Rob
Inadequate remyelination of brain white matter lesions has been associated with a failure of oligodendrocyte precursors to differentiate into mature, myelin-producing cells. In order to better understand which genes play a critical role in oligodendrocyte differentiation, we performed time-dependent, genome-wide gene expression studies of mouse Oli-neu cells as they differentiate into process-forming and myelin basic protein-producing cells, following treatment with three different agents. Our data indicate that different inducers activate distinct pathways that ultimately converge into the completely differentiated state, where regulated gene sets overlap maximally. In order to also gain insight into the functional role of genes that are regulated in this process, we silenced 88 of these genes using small interfering RNA and identified multiple repressors of spontaneous differentiation of Oli-neu, most of which were confirmed in rat primary oligodendrocyte precursors cells. Among these repressors were CNP, a well-known myelin constituent, and three phosphatases, each known to negatively control mitogen-activated protein kinase cascades. We show that a novel inhibitor for one of the identified genes, dual-specificity phosphatase DUSP10/MKP5, was also capable of inducing oligodendrocyte differentiation in primary oligodendrocyte precursors. Oligodendrocytic differentiation feedback loops may therefore yield pharmacological targets to treat disease related to dysfunctional myelin deposition.
Full Text Available Abstract Background Periventricular leukomalacia (PVL is a frequent complication of preterm delivery. Proinflammatory cytokines, such as interferon-γ (IFN-γ and tumor necrosis factor α (TNF-α released from astrocytes and microglia activated by infection or ischemia have previously been shown to impair survival and maturation of oligodendrocyte progenitors and could thus be considered as potential factors contributing to the generation of this disease. The first goal of the present study was to investigate whether exposure of oligodendrocyte precursors to these cytokines arrests the maturation of ion currents in parallel to its effects on myelin proteins and morphological maturation. Secondly, in the search for agents, that can protect differentiating oligodendrocyte precursor cells from cytokine-induced damage we investigated effects of coapplications of corticosteroids with proinflammatory cytokines on the subsequent survival and differentiation of oligodendrocyte progenitor cells. Methods To exclude influences from factors released from other cell types purified cultures of oligodendrocyte precursors were exposed to cytokines and/or steroids and allowed to differentiate for further 6 days in culture. Changes in membrane surface were investigated with capacitance recordings and Scanning Ion Conductance Microscopy. Na+- and K+- currents were investigated using whole cell patch clamp recordings. The expression of myelin specific proteins was investigated using western blots and the precursor cells were identified using immunostaining with A2B5 antibodies. Results Surviving IFN-γ and TNF-α treated cells continued to maintain voltage-activated Na+- and K+ currents characteristic for the immature cells after 6 days in differentiation medium. Corticosterone, dihydrocorticosterone and, most prominently dexamethasone, counteracted the deleterious effects of IFN-γ and TNF-α on cell survival, A2B5-immunostaining and expression of myelin basic
Wang, Li-Chun; Almazan, Guillermina
During development, the secreted molecule Sonic Hedgehog (Shh) is required for lineage specification and proliferation of oligodendrocyte progenitors (OLPs), which are the glia cells responsible for the myelination of axons in the central nervous system (CNS). Shh signaling has been implicated in controlling both the generation of oligodendrocytes (OLGs) during embryonic development and their production in adulthood. Although, some evidence points to a role of Shh signaling in OLG development, its involvement in OLG differentiation remains to be fully determined. The objective of this study was to assess whether Shh signaling is involved in OLG differentiation after neural stem cell commitment to the OLG lineage. To address these questions, we manipulated Shh signaling using cyclopamine, a potent inhibitor of Shh signaling activator Smoothened (Smo), alone or combined with the agonist SAG in OLG primary cultures and assessed expression of myelin-specific markers. We found that inactivation of Shh signaling caused a dose-dependent decrease in myelin basic protein (MBP) and myelin associated glycoprotein (MAG) in differentiating OLGs. Co-treatment of the cells with SAG reversed the inhibitory effect of cyclopamine on both myelin-specific protein levels and morphological changes associated with it. Further experiments are required to elucidate the molecular mechanism by which Shh signaling regulates OLG differentiation.
Full Text Available Myelination of axons by oligodendrocytes in the central nervous system is essential for normal neuronal functions. The failure of remyelination due to injury or pathological insults results in devastating demyelinating diseases. Oligodendrocytes originate in restricted regions of the embryonic ventral neural tube. After migration to populate all areas of the brain and spinal cord, they undergo a temporally well-defined series of molecular and structural changes, ultimately culminating in the cessation of proliferation, and the elaboration of a highly complex myelin sheath. The emergence of microRNAs as potent regulators of gene expression at the post-transcriptional level has broad implications in all facets of biology. Recent studies have demonstrated a critical role of microRNAs in oligodendrocyte development, including cell proliferation, maturation, and myelin formation. In this review, we will highlight and discuss the recent understanding of functional links of miRNAs to regulatory networks for central myelination, as well as perspectives on the role of miRNAs in demyelinating diseases.
Lim, Jamie L; van der Pol, Susanne M A; Baron, Wia; McCord, Joe M; de Vries, Helga E; van Horssen, Jack
Oligodendrocyte damage and loss are key features of multiple sclerosis (MS) pathology. Oligodendrocytes appear to be particularly vulnerable to reactive oxygen species (ROS) and cytokines, such as tumor necrosis factor-α (TNF), which induce cell death and prevent the differentiation of
Lim, Jamie L; van der Pol, Susanne M A; Baron, Wia; McCord, Joe M; de Vries, Helga E; van Horssen, Jack
Oligodendrocyte damage and loss are key features of multiple sclerosis (MS) pathology. Oligodendrocytes appear to be particularly vulnerable to reactive oxygen species (ROS) and cytokines, such as tumor necrosis factor-α (TNF), which induce cell death and prevent the differentiation of oligodendrocy
Full Text Available Myelin oligodendrocyte glycoprotein (MOG, a member of the immunoglobulin (Ig superfamily, is a myelin protein solely expressed at the outermost surface of myelin sheaths and oligodendrocyte membranes. This makes MOG a potential target of cellular and humoral immune responses in inflammatory demyelinating diseases. Due to its late postnatal developmental expression, MOG is an important marker for oligodendrocyte maturation. Discovered about 30 years ago, it is one of the best-studied autoantigens for experimental autoimmune models for multiple sclerosis (MS. Human studies, however, have yielded controversial results on the role of MOG, especially MOG antibodies (Abs, as a biomarker in MS. But with improved detection methods using different expression systems to detect Abs in patients’ samples, this is meanwhile no longer the case. Using cell-based assays with recombinant full-length, conformationally intact MOG, several recent studies have revealed that MOG Abs can be found in a subset of predominantly pediatric patients with acute disseminated encephalomyelitis (ADEM, aquaporin-4 (AQP4 seronegative neuromyelitis optica spectrum disorders (NMOSD, monophasic or recurrent isolated optic neuritis (ON, or transverse myelitis, in atypical MS and in N-methyl-d-aspartate receptor-encephalitis with overlapping demyelinating syndromes. Whereas MOG Abs are only transiently observed in monophasic diseases such as ADEM and their decline is associated with a favorable outcome, they are persistent in multiphasic ADEM, NMOSD, recurrent ON, or myelitis. Due to distinct clinical features within these diseases it is controversially disputed to classify MOG Ab-positive cases as a new disease entity. Neuropathologically, the presence of MOG Abs is characterized by MS-typical demyelination and oligodendrocyte pathology associated with Abs and complement. However, it remains unclear whether MOG Abs are a mere inflammatory bystander effect or truly pathogenetic
Xu, Leyan; Ryu, Jiwon; Hiel, Hakim; Menon, Adarsh; Aggarwal, Ayushi; Rha, Elizabeth; Mahairaki, Vasiliki; Cummings, Brian J; Koliatsos, Vassilis E
Diffuse axonal injury is an extremely common type of traumatic brain injury encountered in motor vehicle crashes, sports injuries, and in combat. Although many cases of diffuse axonal injury result in chronic disability, there are no current treatments for this condition. Its basic lesion, traumatic axonal injury, has been aggressively modeled in primate and rodent animal models. The inexorable axonal and perikaryal degeneration and dysmyelination often encountered in traumatic axonal injury calls for regenerative therapies, including therapies based on stem cells and precursors. Here we explore the proof of concept that treatments based on transplants of human oligodendrocyte progenitor cells can replace or remodel myelin and, eventually, contribute to axonal regeneration in traumatic axonal injury. We derived human oligodendrocyte progenitor cells from the human embryonic stem cell line H9, purified and characterized them. We then transplanted these human oligodendrocyte progenitor cells into the deep sensorimotor cortex next to the corpus callosum of nude rats subjected to traumatic axonal injury based on the impact acceleration model of Marmarou. We explored the time course and spatial distribution of differentiation and structural integration of these cells in rat forebrain. At the time of transplantation, over 90 % of human oligodendrocyte progenitor cells expressed A2B5, PDGFR, NG2, O4, Olig2 and Sox10, a profile consistent with their progenitor or early oligodendrocyte status. After transplantation, these cells survived well and migrated massively via the corpus callosum in both injured and uninjured brains. Human oligodendrocyte progenitor cells displayed a striking preference for white matter tracts and were contained almost exclusively in the corpus callosum and external capsule, the striatopallidal striae, and cortical layer 6. Over 3 months, human oligodendrocyte progenitor cells progressively matured into myelin basic protein(+) and adenomatous
Ogawa, Shin-ichiro; Tokumoto, Yasuhito; Miyake, Jun; Nagamune, Teruyuki
Induced pluripotent stem cells (iPSCs) prepared from somatic cells might become a novel therapeutic tool in regenerative medicine, especially for the central nervous system (CNS). In this study, we attempted to induce O4-positive (O4(+)) oligodendrocytes from adult human fibroblast-derived iPSCs in vitro. We used two adult human iPSC cell lines, 201B7 and 253G1. 201B7 was induced by four-gene transduction (oct4, sox2, klf4, c-myc), and 253G1 was induced by three-gene transduction (oct4, sox2, klf4). We treated these cells with two in vitro oligodendrocyte-directed differentiation protocols that were optimized for human embryonic stem cells. One protocol used platelet-derived growth factor as the major mitogen for oligodendrocyte lineage cells, and the other protocol used epidermal growth factor (EGF) as the mitogen. Although the differentiation efficiency was low (less than 0.01%), we could induce O4(+) oligodendrocytes from 253G1 cells using the EGF-dependent differentiation protocol. This is the first report of the in vitro induction of oligodendrocytes differentiation from human iPSCs.
Cai, Jun; Zhang, Yi Ping; Shields, Lisa B E; Zhang, Zoe Z; Liu, Naikui; Xu, Xiao-Ming; Feng, Shi-Qing; Shields, Christopher B
This study investigated electrophysiological and histological changes as well as alterations of myelin relevant proteins of descending motor tracts in rat pups. Motor-evoked potentials (MEPs) represent descending conducting responses following stimulation of the motor cortex to responses being elicited from the lower extremities. MEP responses were recorded biweekly from postnatal (PN) week 1 to week 9 (adult). MEP latencies in PN week 1 rats averaged 23.7 ms and became shorter during early maturation, stabilizing at 6.6 ms at PN week 4. During maturation, the conduction velocity (CV) increased from 2.8 ± 0.2 at PN week 1 to 35.2 ± 3.1 mm/ms at PN week 8. Histology of the spinal cord and sciatic nerves revealed progressive axonal myelination. Expression of the oligodendrocyte precursor markers PDGFRα and NG2 were downregulated in spinal cords, and myelin-relevant proteins such as GalC, CNP, and MBP increased during maturation. Oligodendrocyte-lineage markers Olig2 and MOG, expressed in myelinated oligodendrocytes, peaked at PN week 3 and were downregulated thereafter. A similar expression pattern was observed in neurofilament M/H subunits that were extensively phosphorylated in adult spinal cords but not in neonatal spinal cords, suggesting an increase in axon diameter and myelin formation. Ultrastructural morphology in the ventrolateral funiculus (VLF) showed axon myelination of the VLF axons (99.3%) at PN week 2, while 44.6% were sheathed at PN week 1. Increased axon diameter and myelin thickness in the VLF and sciatic nerves were highly correlated to the CV (rs > 0.95). This suggests that MEPs could be a predicator of morphological maturity of myelinated axons in descending motor tracts.
Full Text Available Multiple sclerosis (MS is a chronic demyelinating disease of unknown etiology that affects the CNS. While current therapies are primarily directed against the immune system, the new challenge is to address progressive MS with remyelinating and neuroprotective strategies. Here, we develop a highly reproducible protocol to efficiently derive oligodendrocyte progenitor cells (OPCs and mature oligodendrocytes from induced pluripotent stem cells (iPSCs. Key elements of our protocol include adherent cultures, dual SMAD inhibition, and addition of retinoids from the beginning of differentiation, which lead to increased yields of OLIG2 progenitors and high numbers of OPCs within 75 days. Furthermore, we show the generation of viral and integration-free iPSCs from primary progressive MS (PPMS patients and their efficient differentiation to oligodendrocytes. PPMS OPCs are functional, as demonstrated by in vivo myelination in the shiverer mouse. These results provide encouraging advances toward the development of autologous cell therapies using iPSCs.
Full Text Available Neuronal circuitry relies to a large extent on the presence of functional myelin produced in the brain by oligodendrocytes. Schizophrenia has been proposed to arise partly from altered brain connectivity. Brain imaging and neuropathologic studies have revealed changes in white matter and reduction in myelin content in patients with schizophrenia. In particular, alterations in the directionality and alignment of axons have been documented in schizophrenia. Moreover, the expression levels of several myelin-related genes are decreased in postmortem brains obtained from patients with schizophrenia. These findings have led to the formulation of the oligodendrocyte/myelin dysfunction hypothesis of schizophrenia. In this review, we present a brief overview of the neuropathologic findings obtained on white matter and oligodendrocyte status observed in schizophrenia patients, and relate these changes to the processes of brain maturation and myelination. We also review recent data on oligodendrocyte/myelin genes, and present some recent mouse models of myelin deficiencies. The use of transgenic and mutant animal models offers a unique opportunity to analyze oligodendrocyte and neuronal changes that may have a clinical impact. Lastly, we present some recent morphological findings supporting possible causal involvement of white and grey matter abnormalities, in the aim of determining the morphologic characteristics of the circuits whose alteration leads to the cortical dysfunction that possibly underlies the pathogenesis of schizophrenia.
Talbott, Jason F; Cao, Qilin; Bertram, James; Nkansah, Michael; Benton, Richard L; Lavik, Erin; Whittemore, Scott R
Delivery of factors capable of promoting oligodendrocyte precursor cell (OPC) survival and differentiation in vivo is an important therapeutic strategy for a variety of pathologies in which demyelination is a component, including multiple sclerosis and spinal cord injury. Ciliary neurotrophic factor (CNTF) is a neuropoietic cytokine that promotes both survival and maturation of a variety of neuronal and glial cell populations, including oligodendrocytes. Present results suggest that, although CNTF has a potent survival and differentiation promoting effect in vitro on OPCs isolated from the adult spinal cord, CNTF administration in vivo is not sufficient to promote oligodendrocyte remyelination in the glial-depleted environment of unilateral ethidium bromide (EB) lesions.
van Tilborg, Erik; Heijnen, Cobi J.; Benders, Manon J.; van Bel, Frank; Fleiss, Bobbi; Gressens, Pierre; Nijboer, Cora H.
Preterm birth is an evolving challenge in neonatal health care. Despite declining mortality rates among extremely premature neonates, morbidity rates remain very high. Currently, perinatal diffuse white matter injury (WMI) is the most commonly observed type of brain injury in preterm infants and has
Mi, Sha; Miller, Robert H; Lee, Xinhua; Scott, Martin L; Shulag-Morskaya, Svetlane; Shao, Zhaohui; Chang, Jufang; Thill, Greg; Levesque, Melissa; Zhang, Mingdi; Hession, Cathy; Sah, Dinah; Trapp, Bruce; He, Zhigang; Jung, Vincent; McCoy, John M; Pepinsky, R Blake
The control of myelination by oligodendrocytes in the CNS is poorly understood. Here we show that LINGO-1 is an important negative regulator of this critical process. LINGO-1 is expressed in oligodendrocytes. Attenuation of its function by dominant-negative LINGO-1, LINGO-1 RNA-mediated interference (RNAi) or soluble human LINGO-1 (LINGO-1-Fc) leads to differentiation and increased myelination competence. Attenuation of LINGO-1 results in downregulation of RhoA activity, which has been implicated in oligodendrocyte differentiation. Conversely, overexpression of LINGO-1 leads to activation of RhoA and inhibition of oligodendrocyte differentiation and myelination. Treatment of oligodendrocyte and neuron cocultures with LINGO-1-Fc resulted in highly developed myelinated axons that have internodes and well-defined nodes of Ranvier. The contribution of LINGO-1 to myelination was verified in vivo through the analysis of LINGO-1 knockout mice. The ability to recapitulate CNS myelination in vitro using LINGO-1 antagonists and the in vivo effects seen in the LINGO-1 knockout indicate that LINGO-1 signaling may be critical for CNS myelination.
Full Text Available Myelination is essential for rapid impulse conduction in the CNS, but what determines whether an individual axon becomes myelinated remains unknown. Here we show, using a myelinating coculture system, that there are two distinct modes of myelination, one that is independent of neuronal activity and glutamate release and another that depends on neuronal action potentials releasing glutamate to activate NMDA receptors on oligodendrocyte lineage cells. Neuregulin switches oligodendrocytes from the activity-independent to the activity-dependent mode of myelination by increasing NMDA receptor currents in oligodendrocyte lineage cells 6-fold. With neuregulin present myelination is accelerated and increased, and NMDA receptor block reduces myelination to far below its level without neuregulin. Thus, a neuregulin-controlled switch enhances the myelination of active axons. In vivo, we demonstrate that remyelination after white matter damage is NMDA receptor-dependent. These data resolve controversies over the signalling regulating myelination and suggest novel roles for neuregulin in schizophrenia and in remyelination after white matter damage.
Sher, Falak; Balasubramaniyan, Veerakumar; Boddeke, Erik; Copray, Sjef
Purpose of review Recent research on oligodendrocyte development has yielded new insights on the involvement of morphogens and differentiation factors in oligodendrogenesis. This knowledge has improved strategies to control neural stem cell-derived oligodendrocyte differentiation and functional matu
Shao, Zhaohui; Lee, Xinhua; Huang, Guanrong; Sheng, Guoqing; Henderson, Christopher E; Louvard, Daniel; Sohn, Jiho; Pepinsky, Blake; Mi, Sha
Differentiation and maturation of oligodendrocyte progenitor cells (OPCs) involve the assembly and disassembly of actin microfilaments. However, how actin dynamics are regulated during this process remains poorly understood. Leucine-rich repeat and Ig-like domain-containing Nogo receptor interacting protein 1 (LINGO-1) is a negative regulator of OPC differentiation. We discovered that anti-LINGO-1 antibody-promoted OPC differentiation was accompanied by upregulation of cytoplasmic gelsolin (cGSN), an abundant actin-severing protein involved in the depolymerization of actin filaments. Treating rat OPCs with cGSN siRNA reduced OPC differentiation, whereas overexpression of cGSN promoted OPC differentiation in vitro and remyelination in vivo Furthermore, coexpression of cGSN and LINGO-1 blocked the inhibitory effect of LINGO-1. Our study demonstrates that cGSN works downstream of LINGO-1 signaling pathway, which enhances actin dynamics and is essential for OPC morphogenesis and differentiation. This finding may lead to novel therapeutic approaches for the treatment of demyelinating diseases such as multiple sclerosis (MS).SIGNIFICANCE STATEMENT Myelin loss and subsequent axon degeneration contributes to a variety of neurological diseases, such as multiple sclerosis (MS). Understanding the regulation of myelination by oligodendrocytes is therefore critical for developing therapies for the treatment of MS. We previously demonstrated that leucine-rich repeat and Ig-like domain-containing Nogo receptor interacting protein 1 (LINGO-1) is a negative regulator of oligodendrocyte differentiation and that anti-LINGO-1 promotes remyelination in preclinical animal models for MS and in a phase II acute optic neuritis clinical trial (RENEW). The mechanism by which LINGO-1 regulates oligodendrocyte differentiation is unknown. Here, we demonstrate that LINGO-1 regulates oligodendrocyte differentiation and maturation through the cytoplasmic gelsolin signaling pathway, providing new
Mack, S.R.; Szuchet, S.; Dawson, G.
Gangliosides are enriched in the nervous system compared to other tissues. The synthesis of gangliosides by monolayer cultures of isolated oligodendrocytes has not previously been investigated. Cells were labeled with (3H) galactose at preselected times and gangliosides isolated by phase partition, purified, and identified by chromatography. Cultured oligodendrocytes showed selectivity in their synthesis of gangliosides, which was expressed in the type of ganglioside synthesized as well as in the change of incorporation over time in culture. For the first ten days, there was very little incorporation of (3H) galactose in gangliosides, but this was followed by a stimulation of uptake for GM3, GM1/GD3, and GD1 gangliosides, reaching a maximum after approximately 25-30 days in vitro. There was little incorporation into GM2 or trisialogangliosides throughout the life of the cultures. Since oligodendrocytes synthesize extensive membranes during this period, one may speculate that the de novo-synthesized gangliosides are used for membranes.
Full Text Available BACKGROUND: Fyn tyrosine kinase-mediated down-regulation of Rho activity through activation of p190RhoGAP is crucial for oligodendrocyte differentiation and myelination. Therefore, the loss of function of its counterpart protein tyrosine phosphatase (PTP may enhance myelination during development and remyelination in demyelinating diseases. To test this hypothesis, we investigated whether Ptprz, a receptor-like PTP (RPTP expressed abuntantly in oligodendrocyte lineage cells, is involved in this process, because we recently revealed that p190RhoGAP is a physiological substrate for Ptprz. METHODOLOGY/PRINCIPAL FINDINGS: We found an early onset of the expression of myelin basic protein (MBP, a major protein of the myelin sheath, and early initiation of myelination in vivo during development of the Ptprz-deficient mouse, as compared with the wild-type. In addition, oligodendrocytes appeared earlier in primary cultures from Ptprz-deficient mice than wild-type mice. Furthermore, adult Ptprz-deficient mice were less susceptible to experimental autoimmune encephalomyelitis (EAE induced by active immunization with myelin/oligodendrocyte glycoprotein (MOG peptide than were wild-type mice. After EAE was induced, the tyrosine phosphorylation of p190RhoGAP increased significantly, and the EAE-induced loss of MBP was markedly suppressed in the white matter of the spinal cord in Ptprz-deficient mice. Here, the number of T-cells and macrophages/microglia infiltrating into the spinal cord did not differ between the two genotypes after MOG immunization. All these findings strongly support the validity of our hypothesis. CONCLUSIONS/SIGNIFICANCE: Ptprz plays a negative role in oligodendrocyte differentiation in early central nervous system (CNS development and remyelination in demyelinating CNS diseases, through the dephosphorylation of substrates such as p190RhoGAP.
Butt, A M; Hornby, M F; Kirvell, S; Berry, M
The AA dimeric form of platelet-derived growth factor (PDGF-AA) is implicated in the differentiation of cells of the oligodendrocyte lineage, which express PDGF receptors of the alpha subunit type (PDGF-alphaR). In the present study, we show that a single injection of PDGF-AA into the cerebrospinal fluid of neonatal rats delays oligodendrocyte differentiation and interrupts the progress of myelination in the anterior medullary velum (AMV), a white matter tract roofing the IVth ventricle of the brain. PDGF-AA or saline was injected intrathecally in postnatal day (P) 7 rats, and the AMV was subsequently removed and immunolabelled with the oligodendrocyte-specific antibody Rip, at P9, P12, and P21, corresponding to postinjection days (PID) 2, 5, and 14. At P9 (PID2), myelination was retarded in PDGF-AA-treated rats as opposed to saline-treated controls but progressed rapidly after P12 (PID5). Quantification supported the qualitative observations that PDGF-AA mediated an acute decrease in the number of Rip+ oligodendrocytes at P9-12, which largely recovered by P21, suggesting that PDGF-AA may have delayed recruitment of myelinating oligodendrocytes. However, the definitive number of Rip+ oligodendrocytes in the AMV was not increased, suggesting that its action as a promoter of early oligodendrocyte survival may not ultimately affect the definitive number of myelinating oliogdendrocytes in vivo. We discuss the possibilities that excess PDGF-AA may have acted on early oligodendrocytes (precursors or preoligodendrocytes) to either (1) delay their differentiation by maintaining them in the cell cycle or (2) accelerate their differentiation, which may result in premature cell death in the absence of synchronised survival signals. This study supports a role for PDGF-AA in the timing of oligodendrocyte differentiation in vivo, as has been shown in vitro.
Butt, A M; Hornby, M F; Ibrahim, M; Kirvell, S; Graham, A; Berry, M
Platelet-derived growth factor (PDGF) is a growth-regulatory dimer with A and B subunits. PDGF-AA, acting via PDGF receptors of the alpha-unit subtype (PDGF-alphaR), is implicated in the differentiation of oligodendrocyte precursors and in the survival of newly formed oligodendrocytes, which gradually lose expression of PDGF-alphaR. However, it is unclear whether terminally differentiated oligodendrocytes express PDGF-alphaR in vivo. To address this question, and to help clarify the role of PDGF-AA in late oligodendrocyte differentiation, we have used double in situ hybridization with digoxigenin- and fluorescein-labeled riboprobes to relate PDGF-alphaR mRNA and myelin basic protein (MBP) mRNA expression in the isolated intact anterior medullary velum (AMV) of rats ages Postnatal Day (P) 10-12 and P30-32. In parallel experiments, AMV were immunolabeled with the oligodendrocyte-specific monoclonal antibody Rip to provide information on oligodendrocyte development and the extent of myelination. At P10, the AMV contained tracts in which axons ranged from unmyelinated to fully myelinated, whereas myelination was complete in P30-32 AMV. The first oligodendrocytes to express MBP mRNA or Rip were promyelinating oligodendrocytes, which had a "star-burst" morphology and had not yet begun to form myelin sheaths. As myelination proceeded, MBP mRNA became dispersed throughout oligodendrocyte units, comprising cell somata, processes, and internodal myelin sheaths. By P30-32, MBP mRNA had been redistributed to the myelin sheaths only, reflecting a change in the site of protein synthesis in mature myelinated axon tracts. At no stage of oligodendrocyte differentiation did we observe cellular coexpression of mRNA for PDGFalphaR and MBP. Our results indicated that oligodendrocytes lost the expression of PDGFalphaR prior to gaining that of myelin gene products, and preclude an action of PDGF-AA on Rip+/MBP+ star-burst promyelinating oligodendrocytes. The spatial and temporal
Zhao, Xiang-Hui; Jin, Wei-Lin; Ju, Gong
Nogo-A has been considered as one of the most important myelin-associated axonal regeneration inhibitors in the central nervous system. Recent studies have demonstrated various additional physiological roles of Nogo family members. To understand the possible effect of Nogo-A on the differentiation of oligodendrocytes, antibodies against distinct extracellular domains of Nogo-A were applied in cell cultures. Oligodendrocyte precursor cells from P2 rat cortex were grown in the presence of monoclonal antibody against the N-terminal inhibitory domain of Nogo-A or the C-terminal 66 amino acid loop of Nogo-A for 3 days, and the antibody treatment resulted in stunted process extension and inhibited differentiation of oligodendrocytes. Concomitant with morphology changes, Rho GTPases activity was greatly increased upon the antibody treatment and the expression level of LINGO-1, which was recently shown to be a negative regulator for the oligodendrocyte maturation, was upregulated in the process of antibody treatment. These results indicate that endogenous Nogo-A expressed in oligodendrocyte may act though Rho GTPase and LINGO-1 to influence the morphological differentiation of oligodendrocytes and will help us to understand the physiology role of Nogo-A in oligodendrocyte biology.
Rojas Monica A
Full Text Available Abstract Background We previously found that cyclooxygenase 2 (COX-2 was expressed in dying oligodendrocytes at the onset of demyelination in the Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD model of multiple sclerosis (MS (Carlson et al. J.Neuroimmunology 2006, 149:40. This suggests that COX-2 may contribute to death of oligodendrocytes. Objective The goal of this study was to examine whether COX-2 contributes to excitotoxic death of oligodendrocytes and potentially contributes to demyelination. Methods The potential link between COX-2 and oligodendrocyte death was approached using histopathology of MS lesions to examine whether COX-2 was expressed in dying oligodendrocytes. COX-2 inhibitors were examined for their ability to limit demyelination in the TMEV-IDD model of MS and to limit excitotoxic death of oligodendrocytes in vitro. Genetic manipulation of COX-2 expression was used to determine whether COX-2 contributes to excitotoxic death of oligodendrocytes. A transgenic mouse line was generated that overexpressed COX-2 in oligodendrocytes. Oligodendrocyte cultures derived from these transgenic mice were used to examine whether increased expression of COX-2 enhanced the vulnerability of oligodendrocytes to excitotoxic death. Oligodendrocytes derived from COX-2 knockout mice were evaluated to determine if decreased COX-2 expression promotes a greater resistance to excitotoxic death. Results COX-2 was expressed in dying oligodendrocytes in MS lesions. COX-2 inhibitors limited demyelination in the TMEV-IDD model of MS and protected oligodendrocytes against excitotoxic death in vitro. COX-2 expression was increased in wild-type oligodendrocytes following treatment with Kainic acid (KA. Overexpression of COX-2 in oligodendrocytes increased the sensitivity of oligodendrocytes to KA-induced excitotoxic death eight-fold compared to wild-type. Conversely, oligodendrocytes prepared from COX-2 knockout mice showed a
Vinet, Jonathan; Lemieux, Philippe; Tamburri, Albert; Tiesinga, Paul; Scafidi, Joseph; Gallo, Vittorio; Sik, Attila
Oligodendrocytes are the myelin-forming cells of the central nervous system that facilitate transmission of axonal electrical impulses. Using transgenic mice expressing 2',3' cyclic nucleotide 3' phosphodiesterase (CNPase)-enhanced green fluorescent protein, a three-dimensional reconstruction tool a
Ana I Amaral
Full Text Available Whereas astrocytes have been in the limelight on the metabolic glucose interaction scene for a while, oligodendrocytes are still waiting for a place. We would like to call oligodendrocyte interaction with astrocytes and neurons: NOA (neuron – oligodendrocyte – astrocyte interactions. One of the reasons to find out more about oligodendrocyte interaction with neurons and astrocytes is to detect markers of healthy oligodendrocyte metabolism, to be used in diagnosis and treatment assessment in diseases such as Perinatal hypoxic-ischemic encephalopathy and multiple sclerosis in which oligodendrocyte function is impaired, possibly due to glutamate toxicity. Glutamate receptors are expressed in oligodendrocytes and also vesicular glutamate release in the white matter has received considerable attention. It is also important to establish if the glial precursor cells recruited to damaged areas are developing oligodendrocyte characteristics or those of astrocytes. Thus, it is important to study astrocytes and oligodendrocytes separately to be able to differentiate between them. This is of particular importance in the white matter where the number of oligodendrocytes is considerable. The present review summarizes the not very extensive information published on glucose metabolism in oligodendrocytes in an attempt to stimulate research into this important field.
Pang, Y; Cai, Z; Rhodes, P G
Oligodendrocytes are the primary cells injured in periventricular leukomalacia (PVL), a predominant form of brain white matter lesion in preterm infants. To explore the possible linkage between white matter injury and maternal infection, purified rat O-2A progenitor (Oligodendrocyte-type 2 astrocyte progenitor) cell cultures were used as a model in studying the effects of lipopolysaccharide (LPS), an endotoxin, on survival and differentiation of oligodendrocytes and the involvement of other glial cells in the effects of LPS. O-2A progenitor cells were cultured from optic nerves of 7-day-old rat pups in a chemically defined medium (CDM). Astrocyte and microglia cell cultures were prepared from the cortex of 1-day-old rat brains in the CDM. Direct treatment of LPS (1 microg/ml) to O-2A cells had no effect on viability or differentiation of these cells. When O-2A progenitor cells were cultured in the conditioned medium obtained from either astrocyte or microglial cell cultures for 48 hr, survival rate and differentiation of O-2A cells into mature oligodendrocytes were greatly enhanced as measured by the MTT assay and immunocytochemistry. The conditioned medium obtained from astrocytes or microglia treated with LPS for 48 hr, however, failed to show such a promotional effect on viability and differentiation of O-2A cells. When 5 microg/ml LPS was used to stimulate astrocytes or microglia, the conditioned medium from these glial cell cultures caused O-2A cell injury. The overall results indicate that astrocytes and microglia may promote viability and differentiation of O-2A progenitor cells under physiological conditions, but they may also mediate cytotoxic effects of LPS on oligodendrocytes under an infectious disease biochemical environment.
Paez, Pablo M; Cheli, Veronica T; Ghiani, Cristina A; Spreuer, Vilma; Handley, Vance W; Campagnoni, Anthony T
Golli myelin basic proteins are necessary for normal myelination, acting via voltage and store-dependent Ca(2+) entry at multiple steps during oligodendrocyte progenitor cell (OPC) development. To date nothing is known regarding the role of golli proteins in demyelination or remyelination events. Here the effects of golli ablation and overexpression in myelin loss and recovery were examined using the cuprizone (CPZ) model of demyelination/remyelination. We found severe demyelination in the corpus callosum (CC) of golli-overexpressing mice (JOE) during the CPZ treatment, which was accompanied by an increased number of reactive astrocytes and activation of microglia/macrophages. During demyelination of JOE brains, a significant increase in the number of proliferating OPCs was found in the CC as well as in the subventricular zone, and our data indicate that these progenitors matured and fully remyelinated the CC of JOE animals after CPZ withdrawal. In contrast, in the absence of golli (golli-KO mice) delayed myelin loss associated with a smaller immune response, and a lower number of OPCs was found in these mice during the CPZ treatment. Furthermore, incomplete remyelination was observed after CPZ removal in large areas of the CC of golli-KO mice, reflecting irregular recovery of the oligodendrocyte population and subsequent myelin sheath formation. Our findings demonstrate that golli proteins sensitize mature oligodendrocytes to CPZ-induced demyelination, while at the same time stimulate the proliferation/recruitment of OPCs during demyelination, resulting in accelerated remyelination.
Full Text Available BACKGROUND: K(V7/KCNQ channels are widely expressed in neurons and they have multiple important functions, including control of excitability, spike afterpotentials, adaptation, and theta resonance. Mutations in KCNQ genes have been demonstrated to associate with human neurological pathologies. However, little is known about whether K(V7/KCNQ channels are expressed in oligodendrocyte lineage cells (OLCs and what their functions in OLCs. METHODS AND FINDINGS: In this study, we characterized K(V7/KCNQ channels expression in rat primary cultured OLCs by RT-PCR, immunostaining and electrophysiology. KCNQ2-5 mRNAs existed in all three developmental stages of rat primary cultured OLCs. K(V7/KCNQ proteins were also detected in oligodendrocyte progenitor cells (OPCs, early developmental stages of OLCs of rat primary cultures and cortex slices. Voltage-clamp recording revealed that the I(M antagonist XE991 significantly reduced K(V7/KCNQ channel current (I(K(Q in OPCs but not in differentiated oligodendrocytes. In addition, inhibition of K(V7/KCNQ channels promoted OPCs motility in vitro. CONCLUSIONS: These findings showed that K(V7/KCNQ channels were functionally expressed in rat primary cultured OLCs and might play an important role in OPCs functioning in physiological or pathological conditions.
Ichihara, Yoshinori; Doi, Toru; Ryu, Youngjae; Nagao, Motoshi; Sawada, Yasuhiro; Ogata, Toru
Oligodendrocyte progenitor cells (OPCs) undergo marked morphological changes to become mature oligodendrocytes, but the metabolic resources for this process have not been fully elucidated. Although lactate, a metabolic derivative of glycogen, has been reported to be consumed in oligodendrocytes as a metabolite, and to ameliorate hypomyelination induced by low glucose conditions, it is not clear about the direct contribution of lactate to cell cycling and differentiation of OPCs, and the source of lactate for remyelination. Therefore, we evaluated the effect of 1,4-dideoxy-1,4-imino-d-arabinitol (DAB), an inhibitor of the glycogen catabolic enzyme glycogen phosphorylase, in a mouse cuprizone model. Cuprizone induced demyelination in the corpus callosum and remyelination occurred after cuprizone treatment ceased. This remyelination was inhibited by the administration of DAB. To further examine whether lactate affects proliferation or differentiation of OPCs, we cultured mouse primary OPC-rich cells and analyzed the effect of lactate. Lactate rescued the slowed cell cycling induced by 0.4 mM glucose, as assessed by the BrdU-positive cell ratio. Lactate also promoted OPC differentiation detected by monitoring the mature oligodendrocyte marker myelin basic protein, in the presence of both 36.6 mM and 0.4 mM glucose. Furthermore, these lactate-mediated effects were suppressed by the reported monocarboxylate transporter inhibitor, α-cyano-4-hydroxy-cinnamate. These results suggest that lactate directly promotes the cell cycling rate and differentiation of OPCs, and that glycogen, one of the sources of lactate, contributes to remyelination in vivo. J. Cell. Physiol. 232: 986-995, 2017. © 2016 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc. © 2016 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.
Dietz, Karen C; Polanco, Jessie J; Pol, Suyog U; Sim, Fraser J
Oligodendrocyte development has been studied for several decades, and has served as a model system for both neurodevelopmental and stem/progenitor cell biology. Until recently, the vast majority of studies have been conducted in lower species, especially those focused on rodent development and remyelination. In humans, the process of myelination requires the generation of vastly more myelinating glia, occurring over a period of years rather than weeks. Furthermore, as evidenced by the presence of chronic demyelination in a variety of human neurologic diseases, it appears likely that the mechanisms that regulate development and become dysfunctional in disease may be, in key ways, divergent across species. Improvements in isolation techniques, applied to primary human neural and oligodendrocyte progenitors from both fetal and adult brain, as well as advancements in the derivation of defined progenitors from human pluripotent stem cells, have begun to reveal the extent of both species-conserved signaling pathways and potential key differences at cellular and molecular levels. In this article, we will review the commonalities and differences in myelin development between rodents and man, describing the approaches used to study human oligodendrocyte differentiation and myelination, as well as heterogeneity within targetable progenitor pools, and discuss the advances made in determining which conserved pathways may be both modeled in rodents and translate into viable therapeutic strategies to promote myelin repair.
Full Text Available The epicardium is the mono-layered epithelium that covers the outer surface of the myocardium from early in cardiac development. Long thought to act merely passively to protect the myocardium from frictional forces in the pericardial cavity during the enduring contraction and expansion cycles of the heart, it is now considered to be a crucial source of cells and signals that direct myocardial growth and formation of the coronary vasculature during development and regeneration. Lineage tracing efforts in the chick, the mouse and the zebrafish unambiguously identified fibroblasts in interstitial and perivascular locations as well as coronary smooth muscle cells as the two major lineages that derive from epithelial-mesenchymal transition and subsequent differentiation from individual epicardial cells. However, controversies exist about an additional endothelial and myocardial fate of epicardial progenitor cells. Here, we review epicardial fate mapping efforts in three vertebrate model systems, describe their conceptual differences and discuss their methodological limitations to reach a consensus of the potential of (pro-epicardial cells in vitro and in vivo.
Full Text Available White matter dysfunction is an important part of many CNS disorders including multiple sclerosis and vascular dementia. Within injured areas, myelin loss and oligodendrocyte death may trigger endogenous attempts at regeneration. However, during disease progression, remyelination failure may eventually occur due to impaired survival/proliferation, migration/recruitment, and differentiation of oligodendrocyte precursor cells (OPCs. The ventricular-subventricular zone (V-SVZ and the subgranular zone are the main sources of neural stem/progenitor cells (NSPCs, which can give rise to neurons as well as OPCs. Under normal conditions in the adult brain, the V-SVZ progenitors generate a large number of neurons with a small number of oligodendrocyte lineage cells. However, after demyelination, the fate of V-SVZ-derived progenitor cells shifts from neurons to OPCs, and these newly generated OPCs migrate to the demyelinating lesions to ease white matter damage. In this mini-review, we will summarize the recent studies on extrinsic (e.g., vasculature, extracellular matrix, cerebrospinal fluid and intrinsic (e.g., transcription factors, epigenetic modifiers factors, which mediate oligodendrocyte generation from the V-SVZ progenitor cells. A deeper understanding of the mechanisms that regulate the fate of V-SVZ progenitor cells may lead to new therapeutic approaches for ameliorating white matter dysfunction and damage in CNS disorders.
Philips, T.; Bento-Abreu, A.; Nonneman, A.; Haeck, W.; Staats, K.; Geelen, V.; Hersmus, N.; Kusters, B.; Bosch, L. Van Den; Damme, P. van; Richardson, W.D.; Robberecht, W.
Oligodendrocytes are well known targets for immune-mediated and infectious diseases, and have been suggested to play a role in neurodegeneration. Here, we report the involvement of oligodendrocytes and their progenitor cells in the ventral grey matter of the spinal cord in amyotrophic lateral sclero
Philips, T.; Bento-Abreu, A.; Nonneman, A.; Haeck, W.; Staats, K.; Geelen, V.; Hersmus, N.; Kusters, B.; Bosch, L. Van Den; Damme, P. van; Richardson, W.D.; Robberecht, W.
Oligodendrocytes are well known targets for immune-mediated and infectious diseases, and have been suggested to play a role in neurodegeneration. Here, we report the involvement of oligodendrocytes and their progenitor cells in the ventral grey matter of the spinal cord in amyotrophic lateral sclero
OSP-Immunofluorescent remyelinating oligodendrocytes in the brainstem of toxically-demyelinated Wistar rats Oligodendrócitos remielinizantes positivos para OSP - proteína específica do oligodendrócito- no tronco encefálico de ratos Wistar desmielinizados toxicamente
Eliza Simone Viégas Sallis
Full Text Available Central nervous system (CNS remyelination following toxically-induced demyelination is a well known process. Oligodendrocytes constitute the bulk of the myelinating cells in the brain whereas Schwann cells overwhelm oligodendrocytes numbers in spinal cord remyelination. Despite the common knowledge of these facts, we still do not know completely the origin of both remyelinating cells. The present study investigated the participation of mature oligodendrocytes in remyelination after ethidium-bromide (EB induced demyelination in the brainstem of normal and cyclosporin A-immunosuppressed Wistar rats. Thirty adult female rats were divided into three experimental groups. In group 1 the rats received a single intracisternal injection of 10 muL of 0.1% ethidium bromide (EB in 0.9% saline (n=10; in group 2 the rats received the EB injection while immunosuppressed with cyclosporin A (n=10; in group 3 the rats received a single 10 muL injection of 0.9% saline while treated with cyclosporin A. The rats were killed at 15, 21 and 31 days after injection. Within the EB lesions, from 15 days onward many cells within the periphery of the lesions stained positive for OSP (oligodendrocyte specific protein a marker for mature oligodendrocytes and myelin. This cell marking signals that, at least, part of the process of repairing the myelin sheaths is carried out by mature cells of the oligodendrocyte lineage.A remielinização do sistema nervoso central após desmielinização tóxica é um processo bem conhecido. No encéfalo, os oligodendrócitos remielinizam uma área maior do que na medula espinhal, onde as células de Schwann são preponderantes. Embora esses fatos sejam bem conhecidos, ainda não se conhece com certeza a origem das células remielinizantes. Esta investigação foi desenhada para esclarecer a participação de oligodendrócitos maduros na reconstrução das bainhas perdidas após a desmielinização induzida por brometo de etídio (BE no
Hong Chen; Yan Zhang; Zhijun Yang; Hongtian Zhang
Human umbilical mesenchymal stem cells from Wharton's jelly of the umbilical cord were induced to differentiate into oligodendrocyte precursor-like cells in vitro. Oligodendrocyte precursor cells were transplanted into contused rat spinal cords. Immunofluorescence double staining indicated that transplanted cells survived in injured spinal cord, and differentiated into mature and immature oligodendrocyte precursor cells. Biotinylated dextran amine tracing results showed that cell transplantation promoted a higher density of the corticospinal tract in the central and caudal parts of the injured spinal cord. Luxol fast blue and toluidine blue staining showed that the volume of residual myelin was significantly increased at 1 and 2 mm rostral and caudal to the lesion epicenter after cell transplantation. Furthermore, immunofluorescence staining verified that the newly regenerated myelin sheath was derived from the central nervous system. Basso, Beattie and Bresnahan testing showed an evident behavioral recovery. These results suggest that human umbilical mesenchymal stem cell-derived oligodendrocyte precursor cells promote the regeneration of spinal axons and myelin sheaths.
Full Text Available Myelin formation and maintenance are crucial for the proper function of the CNS and are orchestrated by a plethora of factors including growth factors, extracellular matrix components, metalloproteases and protease inhibitors. Hemopexin (Hx is a plasma protein with high heme binding affinity, which is also locally produced in the CNS by ependymal cells, neurons and glial cells. We have recently reported that oligodendrocytes (OLs are the type of cells in the brain that are most susceptible to lack of Hx, as the number of iron-overloaded OLs increases in Hx-null brain, leading to oxidative tissue damage. In the current study, we found that the expression of the Myelin Basic Protein along with the density of myelinated fibers in the basal ganglia and in the motor and somatosensory cortex of Hx-null mice were strongly reduced starting at 2 months and progressively decreased with age. Myelin abnormalities were confirmed by electron microscopy and, at the functional level, resulted in the inability of Hx-null mice to perform efficiently on the Rotarod. It is likely that the poor myelination in the brain of Hx-null mice was a consequence of defective maturation of OLs as we demonstrated that the number of mature OLs was significantly reduced in mutant mice whereas that of precursor cells was normal. Finally, in vitro experiments showed that Hx promotes OL differentiation. Thus, Hx may be considered a novel OL differentiation factor and the modulation of its expression in CNS may be an important factor in the pathogenesis of human neurodegenerative disorders.
Full Text Available BACKGROUND: In vertebrates, the myelin sheath is essential for efficient propagation of action potentials along the axon shaft. Oligodendrocytes are the cells of the central nervous system that create myelin sheaths. During embryogenesis, ventral neural tube precursors give rise to oligodendrocyte progenitor cells, which divide and migrate throughout the central nervous system. This study aimed to investigate mechanisms that regulate oligodendrocyte progenitor cell formation. METHODOLOGY/PRINCIPAL FINDINGS: By conducting a mutagenesis screen in transgenic zebrafish, we identified a mutation, designated vu166, by an apparent reduction in the number of oligodendrocyte progenitor cells in the dorsal spinal cord. We subsequently determined that vu166 is an allele of pescadillo, a gene known to play a role in ribosome biogenesis and cell proliferation. We found that pescadillo function is required for both the proper number of oligodendrocyte progenitors to form, by regulating cell cycle progression, and for normal levels of myelin gene expression. CONCLUSIONS/SIGNIFICANCE: Our data provide evidence that neural precursors require pes function to progress through the cell cycle and produce oligodendrocyte progenitor cells and for oligodendrocyte differentiation.
Janusz Joachim Jadasz
Full Text Available Oligodendroglial progenitor/precursor cells (OPCs represent the main cellular source for the generation of new myelinating oligodendrocytes in the adult central nervous system (CNS. In demyelinating diseases such as multiple sclerosis (MS myelin repair activities based on recruitment, activation and differentiation of resident OPCs can be observed. However, the overall degree of successful remyelination is limited and the existence of an MS-derived anti-oligodendrogenic milieu prevents OPCs from contributing to myelin repair. It is therefore of considerable interest to understand oligodendroglial homeostasis and maturation processes in order to enable the development of remyelination therapies. Mesenchymal stem cells (MSC have been shown to exert positive immunomodulatory effects, reduce demyelination, increase neuroprotection and to promote adult neural stem cell differentiation towards the oligodendroglial lineage. We here addressed whether MSC secreted factors can boost the OPC's oligodendrogenic capacity in a myelin non-permissive environment. To this end, we analyzed cellular morphologies, expression and regulation of key factors involved in oligodendroglial fate and maturation of primary rat cells upon incubation with MSC-conditioned medium. This demonstrated that MSC-derived soluble factors promote and accelerate oligodendroglial differentiation, even under astrocytic endorsing conditions. Accelerated maturation resulted in elevated levels of myelin expression, reduced glial fibrillary acidic protein expression and was accompanied by downregulation of prominent inhibitory differentiation factors such as Id2 and Id4. We thus conclude that apart from their suggested application as potential anti-inflammatory and immunomodulatory MS treatment, these cells might also be exploited to support endogenous myelin repair activities.
Michalski, John-Paul; Cummings, Sarah E; O'Meara, Ryan W; Kothary, Rashmi
Integrin-linked kinase (ILK), a focal adhesion protein, brokers the link between cytoskeleton, cell membrane, and extracellular environment. Here, we demonstrate a role for ILK in laminin-2-mediated adhesion in primary murine oligodendrocytes (OLs) - with ILK loss leading to severe defects in process branching and outgrowth. These defects were partially recovered when the ILK-depleted OLs were instead grown on the non-integrin-activating substrate poly-l-lysine. Intriguingly, ILK loss on the neutral poly-l-lysine substrate led to swelling at the tips of OL processes, which we identified as enlarged growth cones. Employing the bloated ILK-depleted growth cones as template, we demonstrate the appearance of distinct cytoskeletal domains within OL growth cones bearing classic neuronal growth cone architecture. Further, microtubule organization was severely perturbed following ILK loss, with centripetal microtubule looping and failure to bundle occurring in a laminin-2-independent manner. Together, our work highlights differences in specific aspects of OL biology as driven by laminin-2-dependent or independent ILK governed mechanisms. We also reinforce the idea of OLs as growth cone bearing cells and describe the neuronal-like cytoskeleton therein. Finally, we demonstrate a role for ILK in OL growth cone maturation through microtubule regulation, the loss of which translates to decreased process length and myelin production capacity. We describe herein how different substrates fundamentally alter the oligodendrocyte's response to loss of integrin-linked kinase (ILK). On laminin-2 (Ln-2), ILK-depleted oligodendrocytes appear stunted and malformed, while on the non-integrin-activating substrate PLL branching and membrane formation are restored. We also reinforce the idea of oligodendrocytes as growth cone-bearing cells, detailing the growth cone's cytoskeletal architecture. Strikingly, loss of ILK on poly-l-lysine leads to growth cone swelling, the structure's size and
Iijima, Keiya; Kurachi, Masashi; Shibasaki, Koji; Naruse, Masae; Puentes, Sandra; Imai, Hideaki; Yoshimoto, Yuhei; Mikuni, Masahiko; Ishizaki, Yasuki
We previously showed that transplantation of brain microvascular endothelial cells (MVECs) greatly stimulated remyelination in the white matter infarct of the internal capsule (IC) induced by endothelin-1 injection and improved the behavioral outcome. In the present study, we examined the effect of MVEC transplantation on the infarct volume using intermittent magnetic resonance image and on the behavior of oligodendrocyte lineage cells histochemically. Our results in vivo show that MVEC transplantation reduced the infarct volume in IC and apoptotic death of oligodendrocyte precursor cells (OPCs). These results indicate that MVECs have a survival effect on OPCs, and this effect might contribute to the recovery of the white matter infarct. The conditioned-medium from cultured MVECs reduced apoptosis of cultured OPCs, while the conditioned medium from cultured fibroblasts did not show such effect. These results suggest a possibility that transplanted MVECs increased the number of OPCs through the release of humoral factors that prevent their apoptotic death. Identification of such humoral factors may lead to the new therapeutic strategy against ischemic demyelinating diseases.
Full Text Available Oxidative stress contributes to pathology associated with inflammatory brain disorders and therapies that upregulate antioxidant pathways may be neuroprotective in diseases such as multiple sclerosis. Dimethyl fumarate, a small molecule therapeutic for multiple sclerosis, activates cellular antioxidant signaling pathways and may promote myelin preservation. However, it is still unclear what mechanisms may underlie this neuroprotection and whether dimethyl fumarate affects oligodendrocyte responses to oxidative stress. Here, we examine metabolic alterations in oligodendrocytes treated with dimethyl fumarate by using a global metabolomic platform that employs both hydrophilic interaction liquid chromatography–mass spectrometry and shotgun lipidomics. Prolonged treatment of oligodendrocytes with dimethyl fumarate induces changes in citric acid cycle intermediates, glutathione, and lipids, indicating that this compound can directly impact oligodendrocyte metabolism. These metabolic alterations are also associated with protection from oxidant challenge. This study provides insight into the mechanisms by which dimethyl fumarate could preserve myelin integrity in patients with multiple sclerosis.
Yongtao Xu; Anmin Chen; Feng Li; Hougeng Lu
In this study, we used insulin-like growth factor-1 to induce bone marrow mesenchymal stem cells (MSCs) to differentiate into oligodendrocyte-like cells. Cell surface marker identification showed that they expressed myelin basic protein and galactosylceramide, two specific markers of oligodendrocytes. These cells were transplanted into rats with acute spinal cord injury at T10. At 8 weeks post-implantation, oligodendrocyte-like cells were observed to have survived at the injury site. The critical angle of the inclined plane, and Basso, Beattie and Bresnahan scores were all increased. Furthermore, latencies of motion-evoked and somatosensory-evoked potentials were decreased. These results demonstrate that transplantation of oligodendrocytic-induced MSCs promote functional recovery of injured spinal cord.
Woo Kyung Kim
Full Text Available In this study, we investigated the secretome of human oligodendrocytes (F3.Olig2 cells generated from human neural stem cells by transduction with the gene encoding the Olig2 transcription factor. Using mRNA sequencing and protein cytokine arrays, we identified a number of biologically important secretory proteins whose expression has not been previously reported in oligodendrocytes. We found that F3.Olig2 cells secrete IL-6, PDGF-AA, GRO, GM-CSF, and M-CSF, and showed prominent expression of their corresponding receptors. Co-expression of ligands and receptors suggests that autocrine signaling loops may play important roles in both differentiation and maintenance of oligodendrocytes. We also found that F3.Olig2 cells secrete matrix metalloproteinases and matrix metalloproteinase-associated proteins associated with functional competence of oligodendrocytes. The results of our secretome analysis provide insights into the functional and molecular details of human oligodendrocytes. To the best of our knowledge, this is the first systematic analysis of the secretome of oligodendrocytes.
Full Text Available Clozapine has stronger systemic metabolic side effects than haloperidol and it was hypothesized that therapeutic antipsychotic and adverse metabolic effects might be related. Considering that cerebral disconnectivity through oligodendrocyte dysfunction has been implicated in schizophrenia, it is important to determine the effect of these drugs on oligodendrocyte energy metabolism and myelin lipid production.Effects of clozapine and haloperidol on glucose and myelin lipid metabolism were evaluated and compared in cultured OLN-93 oligodendrocytes. First, glycolytic activity was assessed by measurement of extra- and intracellular glucose and lactate levels. Next, the expression of glucose (GLUT and monocarboxylate (MCT transporters was determined after 6h and 24h. And finally mitochondrial respiration, acetyl-CoA carboxylase, free fatty acids, and expression of the myelin lipid galactocerebroside were analyzed.Both drugs altered oligodendrocyte glucose metabolism, but in opposite directions. Clozapine improved the glucose uptake, production and release of lactate, without altering GLUT and MCT. In contrast, haloperidol led to higher extracellular levels of glucose and lower levels of lactate, suggesting reduced glycolysis. Antipsychotics did not alter significantly the number of functionally intact mitochondria, but clozapine enhanced the efficacy of oxidative phosphorylation and expression of galactocerebroside.Our findings support the superior impact of clozapine on white matter integrity in schizophrenia as previously observed, suggesting that this drug improves the energy supply and myelin lipid synthesis in oligodendrocytes. Characterizing the underlying signal transduction pathways may pave the way for novel oligodendrocyte-directed schizophrenia therapies.
Matute, Carlos; Sánchez-Gómez, M. Victoria; Martínez-Millán, Luis; Miledi, Ricardo
In cultured oligodendrocytes isolated from perinatal rat optic nerves, we have analyzed the expression of ionotropic glutamate receptor subunits as well as the effect of the activation of these receptors on oligodendrocyte viability. Reverse transcription–PCR, in combination with immunocytochemistry, demonstrated that most oligodendrocytes differentiated in vitro express the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluR3 and GluR4 and the kainate receptor subunits GluR6, GluR7, KA1 and KA2. Acute and chronic exposure to kainate caused extensive oligodendrocyte death in culture. This effect was partially prevented by the AMPA receptor antagonist GYKI 52466 and was completely abolished by the non-N-methyl-d-aspartate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), suggesting that both AMPA and kainate receptors mediate the observed kainate toxicity. Furthermore, chronic application of kainate to optic nerves in vivo resulted in massive oligodendrocyte death which, as in vitro, could be prevented by coinfusion of the toxin with CNQX. These findings suggest that excessive activation of the ionotropic glutamate receptors expressed by oligodendrocytes may act as a negative regulator of the size of this cell population. PMID:9238063
Flygt, Johanna; Gumucio, Astrid; Ingelsson, Martin; Skoglund, Karin; Holm, Jonatan; Alafuzoff, Irina; Marklund, Niklas
Oligodendrocyte (OL) death may contribute to white matter pathology, a common cause of network dysfunction and persistent cognitive problems in patients with traumatic brain injury (TBI). Oligodendrocyte progenitor cells (OPCs) persist throughout the adult CNS and may replace dead OLs. OL death and OPCs were analyzed by immunohistochemistry of human brain tissue samples, surgically removed due to life-threatening contusions and/or focal brain swelling at 60.6 ± 75 hours (range 4-192 hours) postinjury in 10 severe TBI patients (age 51.7 ± 18.5 years). Control brain tissue was obtained postmortem from 5 age-matched patients without CNS disorders. TUNEL and CC1 co-labeling was used to analyze apoptotic OLs, which were increased in injured brain tissue (p number of single-labeled Olig2, A2B5, NG2, and PDGFR-α-positive cells, numbers of Olig2 and A2B5 co-labeled cells were increased in TBI samples (p < 0.05); this was inversely correlated with time from injury to surgery (r = -0.8, p < 0.05). These results indicate that severe focal human TBI results in OL death and increases in OPCs postinjury, which may influence white matter function following TBI.
Since monumental studies from scientists like His, Ramón y Cajal, Lorente de Nó and many others have put down roots for modern neuroscience, the scientific community has spent a considerable amount of time, and money, investigating any aspect of the evolution, development and function of neurons. Today, the complexity and diversity of myriads of neuronal populations is still focus of extensive studies in hundreds of laboratories around the world. However, our prevalent neuron-centric perspect...
Since monumental studies from scientists like His, Ramón y Cajal, Lorente de Nó and many others have put down roots for modern neuroscience, the scientific community has spent a considerable amount of time, and money, investigating any possible aspect of the evolution, development and function of neurons. Today, the complexity and diversity of myriads of neuronal populations, and their progenitors, is still focus of extensive studies in hundreds of laboratories around the world. However, our ...
Wu, Chuanshen; Chang, Ansi; Smith, Maria C; Won, Roy; Yin, Xinghua; Staugaitis, Susan M; Agamanolis, Dimitri; Kidd, Grahame J; Miller, Robert H; Trapp, Bruce D
We have identified a novel population of cells in the subventricular zone (SVZ) of the mammalian brain that expresses beta4 tubulin (betaT4) and has properties of primitive neuroectodermal cells. betaT4 cells are scattered throughout the SVZ of the lateral ventricles in adult human brain and are significantly increased in the SVZs bordering demyelinated white matter in multiple sclerosis brains. In human fetal brain, betaT4 cell densities peak during the latter stages of gliogenesis, which occurs in the SVZ of the lateral ventricles. betaT4 cells represent 95% of cells in neurospheres treated with the anti-mitotic agent Ara C. betaT4 cells produce oligodendrocytes, neurons, and astrocytes in vitro. We compared the myelinating potential of betaT4-positive cells with A2B5-positive oligodendrocyte progenitor cells after transplantation (25,000 cells) into postnatal day 3 (P3) myelin-deficient rat brains. At P20, the progeny of betaT4 cells myelinated up to 4 mm of the external capsule, which significantly exceeded that of transplanted A2B5-positive progenitor cells. Such extensive and rapid mature CNS cell generation by a relatively small number of transplanted cells provides in vivo support for the therapeutic potential of betaT4 cells. We propose that betaT4 cells are an endogenous cell source that can be recruited to promote neural repair in the adult telencephalon.
Barley, Kevin; Dracheva, Stella; Byne, William
mature oligodendrocytes as well as with bipotential OLPs. Multiple negative correlations were observed between the mRNA expression of astrocyte genes and genes expressed by terminally differentiated oligodendrocytes. These data are discussed in the context of myelin turnover and potential effects of psychiatric illness as well as medications on the developmental fate of OLPs.
Lamprianou, Smaragda; Chatzopoulou, Elli; Thomas, Jean-Léon; Bouyain, Samuel; Harroch, Sheila (IP-Korea); (UPMC); (UMKC)
The six members of the contactin (CNTN) family of neural cell adhesion molecules are involved in the formation and maintenance of the central nervous system (CNS) and have been linked to mental retardation and neuropsychiatric disorders such as autism. Five of the six CNTNs bind to the homologous receptor protein tyrosine phosphatases gamma (PTPRG) and zeta (PTPRZ), but the biological roles of these interactions remain unclear. We report here the cocrystal structure of the carbonic anhydrase-like domain of PTPRZ bound to tandem Ig repeats of CNTN1 and combine these structural data with binding assays to show that PTPRZ binds specifically to CNTN1 expressed at the surface of oligodendrocyte precursor cells. Furthermore, analyses of glial cell populations in wild-type and PTPRZ-deficient mice show that the binding of PTPRZ to CNTN1 expressed at the surface of oligodendrocyte precursor cells inhibits their proliferation and promotes their development into mature oligodendrocytes. Overall, these results implicate the PTPRZ/CNTN1 complex as a previously unknown modulator of oligodendrogenesis.
Full Text Available Demyelination is generally regarded as a consequence of oligodendrocytic cell death. Oligodendrocyte processes that form myelin sheaths may, however, degenerate and regenerate independently of the cell body, in which case cell death does not necessarily occur. We provide here the first evidence of retraction and regeneration of oligodendrocyte processes with no cell death in vitro, using time-lapse imaging. When processes were severed mechanically in vitro, the cells did not undergo cell death and the processes regenerated in 36 h. In a separate experiment, moderate N-methyl-D-aspartate (NMDA stimuli caused process retraction without apparent cell death, and the processes regained their elaborate morphology after NMDA was removed from the culture medium. These results strongly suggest that demyelination and remyelination can take place without concomitant cell death, at least in vitro. Process regeneration may therefore become a target for future therapy of demyelinating disorders.
Domercq, Maria; Perez-Samartin, Alberto; Aparicio, David; Alberdi, Elena; Pampliega, Olatz; Matute, Carlos
Brain ischemia leading to stroke is a major cause of disability in developed countries. Therapeutic strategies have most commonly focused on protecting neurons from ischemic damage. However, ischemic damage to white matter causes oligodendrocyte death, myelin disruption, and axon dysfunction, and it is partially mediated by glutamate excitotoxicity. We have previously demonstrated that oligodendrocytes express ionotropic purinergic receptors. The objective of this study was to investigate the role of purinergic signaling in white matter ischemia. We show that, in addition to glutamate, enhanced ATP signaling during ischemia is also deleterious to oligodendrocytes and myelin, and impairs white matter function. Thus, ischemic oligodendrocytes in culture display an inward current and cytosolic Ca(2+) overload, which is partially mediated by P2X7 receptors. Indeed, oligodendrocytes release ATP after oxygen and glucose deprivation through the opening of pannexin hemichannels. Consistently, ischemia-induced mitochondrial depolarization as well as oxidative stress culminating in cell death are partially reversed by P2X7 receptor antagonists, by the ATP degrading enzyme apyrase and by blockers of pannexin hemichannels. In turn, ischemic damage in isolated optic nerves, which share the properties of brain white matter, is greatly attenuated by all these drugs. Ultrastructural analysis and electrophysiological recordings demonstrated that P2X7 antagonists prevent ischemic damage to oligodendrocytes and myelin, and improved action potential recovery after ischemia. These data indicate that ATP released during ischemia and the subsequent activation of P2X7 receptor is critical to white matter demise during stroke and point to this receptor type as a therapeutic target to limit tissue damage in cerebrovascular diseases.
Ahdeah Pajoohesh-Ganji; Robert H. Miller
Multiple sclerosis (MS) is an autoimmune mediated neurodegenerative disease characterized by demyelin-ation and oligodendrocyte (OL) loss in the central nervous system and accompanied by local inlfammation and inifltration of peripheral immune cells. Although many risk factors and symptoms have been iden-tified in MS, the pathology is complicated and the cause remains unknown. It is also unclear whether OL apoptosis precedes the inlfammation or whether the local inlfammation is the cause of OL death and demyelination. This review brielfy discusses several models that have been developed to speciifcally ablate oligodendrocytes in an effort to separate the effects of demyelination from inlfammation.
Jens O Watzlawik
Full Text Available BACKGROUND: Promotion of remyelination is a major goal in treating demyelinating diseases such as multiple sclerosis (MS. The recombinant human monoclonal IgM, rHIgM22, targets myelin and oligodendrocytes (OLs and promotes remyelination in animal models of MS. It is unclear whether rHIgM22-mediated stimulation of lesion repair is due to promotion of oligodendrocyte progenitor cell (OPC proliferation and survival, OPC differentiation into myelinating OLs or protection of mature OLs. It is also unknown whether astrocytes or microglia play a functional role in IgM-mediated lesion repair. METHODS: We assessed the effect of rHIgM22 on cell proliferation in mixed CNS glial and OPC cultures by tritiated-thymidine uptake and by double-label immunocytochemistry using the proliferation marker, Ki-67. Antibody-mediated signaling events, OPC differentiation and OPC survival were investigated and quantified by Western blots. RESULTS: rHIgM22 stimulates OPC proliferation in mixed glial cultures but not in purified OPCs. There is no proliferative response in astrocytes or microglia. rHIgM22 activates PDGFαR in OPCs in mixed glial cultures. Blocking PDGFR-kinase inhibits rHIgM22-mediated OPC proliferation in mixed glia. We confirm in isolated OPCs that rHIgM22-mediated anti-apoptotic signaling and inhibition of OPC differentiation requires PDGF and FGF-2. We observed no IgM-mediated effect in mature OLs in the absence of PDGF and FGF-2. CONCLUSION: Stimulation of OPC proliferation by rHIgM22 depends on co-stimulatory astrocytic and/or microglial factors. We demonstrate that rHIgM22-mediated activation of PDGFαR is required for stimulation of OPC proliferation. We propose that rHIgM22 lowers the PDGF threshold required for OPC proliferation and protection, which can result in remyelination of CNS lesions.
Murcia-Belmonte, Verónica; Esteban, Pedro F; Martínez-Hernández, José; Gruart, Agnès; Luján, Rafael; Delgado-García, José María; de Castro, Fernando
During development of the central nervous system, anosmin-1 (A1) works as a chemotropic cue contributing to axonal outgrowth and collateralization, as well as modulating the migration of different cell types, fibroblast growth factor receptor 1 (FGFR1) being the main receptor involved in all these events. To further understand the role of A1 during development, we have analysed the over-expression of human A1 in a transgenic mouse line. Compared with control mice during development and in early adulthood, A1 over-expressing transgenic mice showed an enhanced oligodendrocyte precursor cell (OPC) proliferation and a higher number of OPCs in the subventricular zone and in the corpus callosum (CC). The migratory capacity of OPCs from the transgenic mice is increased in vitro due to a higher basal activation of ERK1/2 mediated through FGFR1 and they also produced more myelin basic protein (MBP). In vivo, the over-expression of A1 resulted in an elevated number of mature oligodendrocytes with higher levels of MBP mRNA and protein, as well as increased levels of activation of the ERK1/2 proteins, while electron microscopy revealed thicker myelin sheaths around the axons of the CC in adulthood. Also in the mature CC, the nodes of Ranvier were significantly longer and the conduction velocity of the nerve impulse in vivo was significantly increased in the CC of A1 over-expressing transgenic mice. Altogether, these data confirmed the involvement of A1 in oligodendrogliogenesis and its relevance for myelination.
Kitada, Masaaki; Takeda, Kazuya; Dezawa, Mari
We previously demonstrated that NG2-positive oligodendrocyte precursor cells (OPCs) do not express DM-20 mRNA and identified a distinct DM-20 mRNA-positive cell population expressing glutathione-S-transferase pi isoform (GST-pi) in the nucleus (GST-pi(Nuc)) of the adult rat spinal cord. As GST-pi intranuclear localization correlates with progenitor cell properties, we examined the differentiation status of this cell population under the intensive 5-bromo-2'-deoxyuridine (BrdU) administration method, consisting of intraperitoneal BrdU injections every 2 h for 48 h. We observed that a certain population of proliferating/proliferated cells expressed DM-20 mRNA, and sometimes two proliferating/proliferated cells were observed still attached to each other. We performed triple staining for BrdU, DM-20 mRNA, and NG2 and found pairs of neighboring BrdU-positive cells, which were considered to originate from the same progenitor cells and where both cells expressed DM-20 mRNA. Triple staining for BrdU, DM-20 mRNA, and GST-pi detected proliferating/proliferated cells exhibiting the GST-pi(Nuc)/DM-20 mRNA-positive expression pattern. These findings suggested the presence of a GST-pi(Nuc)/DM-20 mRNA-positive oligodendrocyte-lineage progenitor cell population in the adult rat spinal cord. However, we did not find any pair of neighboring BrdU-positive cells with this expression pattern. These observations collectively support the idea that GST-pi(Nuc)/DM-20 mRNA-expressing cells are the progeny of NG2-positive OPCs rather than a novel type of oligodendrocyte-lineage progenitor cells and that DM-20 mRNA expression is dynamically regulated during differentiation of OPCs into oligodendrocytes.
Maldonado, Paloma P; Angulo, María Cecilia
The surprising discovery of bona fide synapses between neurons and oligodendrocytes precursor cells (OPCs) 15 years ago placed these progenitors as real partners of neurons in the CNS. The role of these synapses has not been established yet, but a main hypothesis is that neuron-OPC synaptic activity
Pinzon-Olejua, Alejandro; Welte, Cornelia; Chekuru, Avinash; Bosak, Viktoria; Brand, Michael; Hans, Stefan; Stuermer, Claudia A O
The conditional Cre/lox system has recently emerged as a valuable tool for studies on both embryonic and adult Zebrafish. Temporal control and site-specific recombination are achieved by using the ligand-inducible CreER(T2) and administration of the drug tamoxifen (TAM) or its active metabolite, 4-Hydroxytamoxifen (4-OHT). Here we report the generation of a transgenic Zebrafish line, which expresses an mCherry-tagged variant of CreER(T2) under the control of the myelin basic protein a (mbpa) promoter. Our analysis shows that larval and adult expression of the transgene recapitulates the endogenous mbpa expression pattern in oligodendrocytes. Furthermore, combination with a Cre-dependent EGFP reporter results in EGFP-expressing oligodendrocytes in the spinal cord, brain, and optic nerve in TAM- or 4-OHT-treated larvae and 4-month-old fish, but not in untreated controls. The transgenic Zebrafish line Tg(mbpa:mCherry-T2A-CreER(T2) ) elicits CreER(T2) expression specifically in myelinating glia cells. Cre-inducible targeted recombination of genes in oligodendrocytes will be useful to elucidate cellular and molecular mechanisms of myelination in vivo during development (myelination) and regeneration (remyelination) after injury to the central nervous system (CNS). It will also allow targeted expression and overexpression of genes of interest (transgenes) in oligodendrocytes at defined developmental and adult stages. Developmental Dynamics 246:41-49, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Maier, Olaf; Hoekstra, Dick; Baron, Wia
In vertebrates, myelination is required for the saltatory signal conductance along the axon. At the onset of myelination, the myelinating cells, i.e., oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system, are heavily engaged in the biogenesis of membranes
Full Text Available Oligodendrocyte precursor cells (OPCs originate in specific areas of the developing central nervous system (CNS. Once generated, they migrate towards their destinations where they differentiate into mature oligodendrocytes. In the adult, 5-8% of all cells in the CNS are OPCs, cells that retain the capacity to proliferate, migrate and differentiate into oligodendrocytes. Indeed, these endogenous OPCs react to damage in demyelinating diseases, like multiple sclerosis (MS, representing a key element in spontaneous remyelination. In the present work, we review the specific interactions between OPCs and other glial cells (astrocytes, microglia during CNS development and in the pathological scenario of MS. We focus on: i the role of astrocytes in maintaining the homeostasis and spatial distribution of different secreted cues that determine OPC proliferation, migration and differentiation during CNS development; ii the role of microglia and astrocytes in the redistribution of iron, which is crucial for myelin synthesis during CNS development and for myelin repair in MS; iii how microglia secrete different molecules, e.g. growth factors, that favor the recruitment of OPCs in acute phases of MS lesions; and iv how astrocytes modify the extracellular matrix in MS lesions, affecting the ability of OPCs to attempt spontaneous remyelination. Together, these issues demonstrate how both astroglia and microglia influence OPCs in physiological and pathological situations, reinforcing the concept that both development and neural repair are complex and global phenomena. Understanding the molecular and cellular mechanisms that control OPC survival, proliferation, migration and differentiation during development, as well as in the mature CNS, may open new opportunities in the search for reparative therapies in demyelinating diseases like MS.
Full Text Available In schizophrenia, previous stereological post-mortem investigations of anterior, posterior, and total hippocampal subfields showed no alterations in total neuron number but did show decreased oligodendrocyte numbers in CA4, an area that corresponds to the polymorph layer of the dentate gyrus. However, these investigations identified oligodendrocytes only on the basis of morphological criteria in Nissl staining and did not assess alterations of interneurons with immunohistochemical markers. Moreover, the association of findings in the posterior hippocampus with cognitive deficits remains unknown.On the basis of the available clinical records, we compared patients with definite and possible cognitive dysfunction; nine patients had evidence in their records of either definite (n=4 or possible (n=5 cognitive dysfunction. Additionally, we assessed the density of two oligodendrocyte subpopulations immunostained by the oligodendrocyte transcription factors Olig1 and Olig2 and of interneurons immunolabeled by parvalbumin. We investigated posterior hippocampal subregions in the post-mortem brains of the same schizophrenia patients (n=10 and healthy controls (n=10 we examined in our previously published stereological studies. Our stereological studies found that patients with definite cognitive deficits had decreased total / Nissl-stained oligodendrocyte numbers in the left (p=0.014 and right (p=0.050 CA4, left CA2/3 (p=0.050, left CA1 (p=0.027, and left (p=0.050 and right (p=0.014 subiculum of the anterior part of the hippocampus compared to patients with possible cognitive deficits. In the present study, we found no significant influence of definite cognitive deficits in the posterior part of the hippocampus, whereas in the entire hippocampus schizophrenia patients with definite cognitive deficits showed decreased oligodendrocyte numbers in the left (p=0.050 and right (p=0.050 dentate gyrus and left CA2/3 (p=0.050. We did not find significant
Full Text Available The NG2 proteoglycan is characteristically expressed by oligodendrocyte progenitor cells (OPC and also by aggressive brain tumours highly resistant to chemo- and radiation therapy. Oligodendrocyte-lineage cells are particularly sensitive to stress resulting in cell death in white matter after hypoxic or ischemic insults of premature infants and destruction of OPC in some types of Multiple Sclerosis lesions. Here we show that the NG2 proteoglycan binds OMI/HtrA2, a mitochondrial serine protease which is released from damaged mitochondria into the cytosol in response to stress. In the cytosol, OMI/HtrA2 initiates apoptosis by proteolytic degradation of anti-apoptotic factors. OPC in which NG2 has been downregulated by siRNA, or OPC from the NG2-knockout mouse show an increased sensitivity to oxidative stress evidenced by increased cell death. The proapoptotic protease activity of OMI/HtrA2 in the cytosol can be reduced by the interaction with NG2. Human glioma expressing high levels of NG2 are less sensitive to oxidative stress than those with lower NG2 expression and reducing NG2 expression by siRNA increases cell death in response to oxidative stress. Binding of NG2 to OMI/HtrA2 may thus help protect cells against oxidative stress-induced cell death. This interaction is likely to contribute to the high chemo- and radioresistance of glioma.
Gryganskyi, A.P.; Humber, R.A.; Smith, M.E.; Hodge, K.; Huang, B.; Voigt, K.; Vilgalys, R.
Entomophthoromycota is one of six major phylogenetic lineages among the former phylum Zygomycota. These early terrestrial fungi share evolutionarily ancestral characters such as coenocytic mycelium and gametangiogamy as a sexual process resulting in zygospore formation. Previous molecular studies ha
Li, Pengyan; Li, Mo; Tang, Xihe; Wang, Shuyan; Zhang, Y Alex; Chen, Zhiguo
Oligodendrocyte progenitor cells (OPCs) hold great promise for treatment of dysmyelinating disorders, such as multiple sclerosis and cerebral palsy. Recent studies on generation of human OPCs mainly use human embryonic stem cells (hESCs) or neural stem cells (NSCs) as starter cell sources for the differentiation process. However, NSCs are restricted in availability and the present method for generation of oligodendrocytes (OLs) from ESCs often requires a lengthy period of time. Here, we demonstrated a protocol to efficiently derive OPCs from human induced pluripotent stem cells (hiPSCs) by forced expression of two transcription factors (2TFs), Sox10 and Olig2. With this method, PDGFRα(+) OPCs can be obtained in 14 days and O4(+) OPCs in 56 days. Furthermore, OPCs may be able to differentiate to mature OLs that could ensheath axons when co-cultured with rat cortical neurons. The results have implications in the development of autologous cell therapies.
Samantha F Kornfeld
Full Text Available Oligodendrocyte differentiation and central nervous system myelination require massive reorganization of the oligodendrocyte cytoskeleton. Loss of specific actin- and tubulin-organizing factors can lead to impaired morphological and/or molecular differentiation of oligodendrocytes, resulting in a subsequent loss of myelination. Dystonin is a cytoskeletal linker protein with both actin- and tubulin-binding domains. Loss of function of this protein results in a sensory neuropathy called Hereditary Sensory Autonomic Neuropathy VI in humans and dystonia musculorum in mice. This disease presents with severe ataxia, dystonic muscle and is ultimately fatal early in life. While loss of the neuronal isoforms of dystonin primarily leads to sensory neuron degeneration, it has also been shown that peripheral myelination is compromised due to intrinsic Schwann cell differentiation abnormalities. The role of this cytoskeletal linker in oligodendrocytes, however, remains unclear. We sought to determine the effects of the loss of neuronal dystonin on oligodendrocyte differentiation and central myelination. To address this, primary oligodendrocytes were isolated from a severe model of dystonia musculorum, Dstdt-27J, and assessed for morphological and molecular differentiation capacity. No defects could be discerned in the differentiation of Dstdt-27J oligodendrocytes relative to oligodendrocytes from wild-type littermates. Survival was also compared between Dstdt-27J and wild-type oligodendrocytes, revealing no significant difference. Using a recently developed migration assay, we further analysed the ability of primary oligodendrocyte progenitor cell motility, and found that Dstdt-27J oligodendrocyte progenitor cells were able to migrate normally. Finally, in vivo analysis of oligodendrocyte myelination was done in phenotype-stage optic nerve, cerebral cortex and spinal cord. The density of myelinated axons and g-ratios of Dstdt-27J optic nerves was normal, as
Wen-li GU; Sai-li FU; Yan-xia WANG; Ying LI; Xiao-fei WANG; Xiao-ming XU; Pei-hua LU
Aim: To have a better understanding of the expression and regulation of versican isoforms in neural precursor cells (NPC) and oligodendrogliogenesis. Methods:By immunocytochemistry, RT-PCR, and real-time PCR, we examined the temporal expression of versican in NPC isolated from embryonic d 16 rats as well as in oligodendrocyte (OL) lineage cells induced to differentiate from NPC,which mimicked the oligodendrogliogenesis in vivo. Results: We found that versican was constitutively expressed in NPC and their lineage cells, including neurons, astrocytes, and OL. In addition, 2 versican isoforms, V1/V0 and V2,were found to express at low levels in NPC, but at significantly higher levels in OL lineage cells. The peak expression of versican V2 was found at the oligodendrocyte precursor cell stage. Furthermore, the treatment of 2 pro-inflammatory cytokines, TNF-α and IFN-γ, enhanced the transcription of versican V2 in NPC in a dose-dependent manner, but showed no effect on V1/V0 expression.Conclusion: Taken together, our results demonstrate that versican, particularly the inhibitory V2 isoform, is increasingly expressed in OL lineage cells induced to differentiate from NPC. An increase in versican V2 expression after cytokine stimulation implies the interplay between the injury-induced upregulation of inflammatory cytokines and chondroitin sulfate proteoglycan-mediated inhibition of axonal regeneration after central nervous system injury.
Full Text Available Oligodendrocytes wrap neuronal axons to form myelin, an insulating sheath which is essential for nervous impulse conduction along axons. Axonal myelination is highly regulated by neuronal and astrocytic signals and the maintenance of myelin sheaths is a very complex process. Oligodendrocyte damage can cause axonal demyelination and neuronal injury, leading to neurological disorders. Demyelination in the cerebrum may produce cognitive impairment in a variety of neurological disorders, including human immunodeficiency virus type one (HIV-1-associated neurocognitive disorders (HAND. Although the combined antiretroviral therapy has markedly reduced the incidence of HIV-1-associated dementia, a severe form of HAND, milder forms of HAND remain prevalent even when the peripheral viral load is well controlled. HAND manifests as a subcortical dementia with damage in the brain white matter (e.g., corpus callosum, which consists of myelinated axonal fibers. How HIV-1 brain infection causes myelin injury and resultant white matter damage is an interesting area of current HIV research. In this review, we tentatively address recent progress on oligodendrocyte dysregulation and HAND pathogenesis.
Full Text Available BACKGROUND: Several clinical conditions are associated with white matter injury, including periventricular white matter injury (PWMI, which is a form of brain injury sustained by preterm infants. It has been suggested that white matter injury in this condition is due to altered oligodendrocyte (OL development or death, resulting in OL loss and hypomyelination. At present drugs are not available that stimulate OL proliferation and promote myelination. Evidence suggests that depolarizing stimuli reduces OL proliferation and differentiation, whereas agents that hyperpolarize OLs stimulate OL proliferation and differentiation. Considering that the drug diazoxide activates K(ATP channels to hyperpolarize cells, we tested if this compound could influence OL proliferation and myelination. METHODOLOGY/FINDINGS: Studies were performed using rat oligodendrocyte precursor cell (OPC cultures, cerebellar slice cultures, and an in vivo model of PWMI in which newborn mice were exposed to chronic sublethal hypoxia (10% O(2. We found that K(ATP channel components Kir 6.1 and 6.2 and SUR2 were expressed in oligodendrocytes. Additionally, diazoxide potently stimulated OPC proliferation, as did other K(ATP activators. Diazoxide also stimulated myelination in cerebellar slice cultures. We also found that diazoxide prevented hypomyelination and ventriculomegaly following chronic sublethal hypoxia. CONCLUSIONS: These results identify KATP channel components in OLs and show that diazoxide can stimulate OL proliferation in vitro. Importantly we find that diazoxide can promote myelination in vivo and prevent hypoxia-induced PWMI.
Liu, Han; Xu, Enquan; Liu, Jianuo; Xiong, Huangui
Oligodendrocytes wrap neuronal axons to form myelin, an insulating sheath which is essential for nervous impulse conduction along axons. Axonal myelination is highly regulated by neuronal and astrocytic signals and the maintenance of myelin sheaths is a very complex process. Oligodendrocyte damage can cause axonal demyelination and neuronal injury, leading to neurological disorders. Demyelination in the cerebrum may produce cognitive impairment in a variety of neurological disorders, including human immunodeficiency virus type one (HIV-1)-associated neurocognitive disorders (HAND). Although the combined antiretroviral therapy has markedly reduced the incidence of HIV-1-associated dementia, a severe form of HAND, milder forms of HAND remain prevalent even when the peripheral viral load is well controlled. HAND manifests as a subcortical dementia with damage in the brain white matter (e.g., corpus callosum), which consists of myelinated axonal fibers. How HIV-1 brain infection causes myelin injury and resultant white matter damage is an interesting area of current HIV research. In this review, we tentatively address recent progress on oligodendrocyte dysregulation and HAND pathogenesis. PMID:27455335
Butt, A M; Ibrahim, M; Ruge, F M; Berry, M
Oligodendrocytes were studied in the anterior medullary velum (AMV) of the rat using the monoclonal antibody Rip, an oligodendrocyte marker of unknown function. Confocal microscopic imaging of double immunofluorescent labelling with antibodies to Rip and carbonic anhydrase II (CAII) revealed two biochemically and morphologically distinct populations of oligodendrocyte which were either Rip+CAII+ or Rip+CAII-. Double immunofluorescent labelling with Rip and myelin basic protein (MBP) or glial fibrillary acidic protein (GFAP) provided direct evidence that Rip-labelled cells were phenotypically oligodendrocytes and confirmed that Rip did not recognise astrocytes. Oligodendrocytes which were Rip+CAII+ supported numerous myelin sheaths for small diameter axons, whilst Rip+CAII- oligodendrocytes supported fewer myelin sheaths for large diameter axons. Morphologically, Rip+CAII+ oligodendrocytes corresponded to types I or II of classical nomenclature, whilst Rip+CAII- oligodendrocytes corresponded to types III and IV. The results demonstrated a biochemical difference between oligodendrocytes which myelinated small and large diameter fibres.
Clarke, Laura E; Young, Kaylene M; Hamilton, Nicola B; Li, Huiliang; Richardson, William D; Attwell, David
Oligodendrocyte progenitor cells (OPCs) in the postnatal mouse corpus callosum (CC) and motor cortex (Ctx) reportedly generate only oligodendrocytes (OLs), whereas those in the piriform cortex may also generate neurons. OPCs have also been subdivided based on their expression of voltage-gated ion channels, ability to respond to neuronal activity, and proliferative state. To determine whether OPCs in the piriform cortex have inherently different physiological properties from those in the CC and Ctx, we studied acute brain slices from postnatal transgenic mice in which GFP expression identifies OL lineage cells. We whole-cell patch clamped GFP-expressing (GFP(+)) cells within the CC, Ctx, and anterior piriform cortex (aPC) and used prelabeling with 5-ethynyl-2'-deoxyuridine (EdU) to assess cell proliferation. After recording, slices were immunolabeled and OPCs were defined by strong expression of NG2. NG2(+) OPCs in the white and gray matter proliferated and coexpressed PDGFRα and voltage-gated Na(+) channels (I(Na)). Approximately 70% of OPCs were capable of generating regenerative depolarizations. In addition to OLIG2(+) NG2(+) I(Na)(+) OPCs and OLIG2(+) NG2(neg) I(Na)(neg) OLs, we identified cells with low levels of NG2 limited to the soma or the base of some processes. These cells had a significantly reduced I(Na) and a reduced ability to incorporate EdU when compared with OPCs and probably correspond to early differentiating OLs. By combining EdU labeling and lineage tracing using Pdgfrα-CreER(T2) : R26R-YFP transgenic mice, we double labeled OPCs and traced their fate in the postnatal brain. These OPCs generated OLs but did not generate neurons in the aPC or elsewhere at any time that we examined.
Teresa L. Wood
Full Text Available Oligodendrocyte development is controlled by numerous extracellular signals that regulate a series of transcription factors that promote the differentiation of oligodendrocyte progenitor cells to myelinating cells in the central nervous system. A major element of this regulatory system that has only recently been studied is the intracellular signalling from surface receptors to transcription factors to down-regulate inhibitors and up-regulate inducers of oligodendrocyte differentiation and myelination. The current review focuses on one such pathway: the mTOR (mammalian target of rapamycin pathway, which integrates signals in many cell systems and induces cell responses including cell proliferation and cell differentiation. This review describes the known functions of mTOR as they relate to oligodendrocyte development, and its recently discovered impact on oligodendrocyte differentiation and myelination. A potential model for its role in oligodendrocyte development is proposed.
Teresa L. Wood
Full Text Available Oligodendrocyte development is controlled by numerous extracellular signals that regulate a series of transcription factors that promote the differentiation of oligodendrocyte progenitor cells to myelinating cells in the central nervous system. A major element of this regulatory system that has only recently been studied is the intracellular signalling from surface receptors to transcription factors to down-regulate inhibitors and up-regulate inducers of oligodendrocyte differentiation and myelination. The current review focuses on one such pathway: the mTOR (mammalian target of rapamycin pathway, which integrates signals in many cell systems and induces cell responses including cell proliferation and cell differentiation. This review describes the known functions of mTOR as they relate to oligodendrocyte development, and its recently discovered impact on oligodendrocyte differentiation and myelination. A potential model for its role in oligodendrocyte development is proposed.
Smith, Chelsey M; Mayer, Joshua A; Duncan, Ian D
The Long-Evans shaker (les) rat has a mutation in myelin basic protein that results in severe CNS dysmyelination and subsequent demyelination during development. During this time, les oligodendrocytes accumulate cytoplasmic vesicles, including lysosomes and membrane-bound organelles. However, the mechanism and functional relevance behind these oligodendrocyte abnormalities in les have not been investigated. Using high-magnification electron microscopy, we identified the accumulations in les oligodendrocytes as early and late autophagosomes. Additionally, immunohistochemistry and Western blots showed an increase in autophagy markers in les. However, autophagy did not precede the death of les oligodendrocytes. Instead, upregulating autophagy promoted membrane extensions in les oligodendrocytes in vitro. Furthermore, upregulating autophagy in les rats via intermittent fasting increased the proportion of myelinated axons as well as myelin sheath thickness in les and control rats. Overall, this study provides insight into the abnormalities described in les as well as identifying a novel mechanism that promotes the survival and function of oligodendrocytes.
Cardano, Marina; Diaferia, Giuseppe R; Cattaneo, Monica; Dessì, Sara S; Long, Qiaoming; Conti, Luciano; Deblasio, Pasquale; Cattaneo, Elena; Biunno, Ida
Murine SEL-1L (mSEL-1L) is a key component of the endoplasmic reticulum-associated degradation pathway. It is essential during development as revealed by the multi-organ dysfunction and in uterus lethality occurring in homozygous mSEL-1L-deficient mice. Here we show that mSEL-1L is highly expressed in pluripotent embryonic stem cells and multipotent neural stem cells (NSCs) but silenced in all mature neural derivatives (i.e. astrocytes, oligodendrocytes, and neurons) by mmu-miR-183. NSCs derived from homozygous mSEL-1L-deficient embryos (mSEL-1L(-/-) NSCs) fail to proliferate in vitro, show a drastic reduction of the Notch effector HES-5, and reveal a significant down-modulation of the early neural progenitor markers PAX-6 and OLIG-2, when compared with the wild type (mSEL-1L(+/+) NSCs) counterpart. Furthermore, these cells are almost completely deprived of the neural marker Nestin, display a significant decrease of SOX-2 expression, and rapidly undergo premature astrocytic commitment and apoptosis. The data suggest severe self-renewal defects occurring in these cells probably mediated by misregulation of the Notch signaling. The results reported here denote mSEL-1L as a primitive marker with a possible involvement in the regulation of neural progenitor stemness maintenance and lineage determination.
Cardano, Marina; Diaferia, Giuseppe R.; Cattaneo, Monica; Dessì, Sara S.; Long, Qiaoming; Conti, Luciano; DeBlasio, Pasquale; Cattaneo, Elena; Biunno, Ida
Murine SEL-1L (mSEL-1L) is a key component of the endoplasmic reticulum-associated degradation pathway. It is essential during development as revealed by the multi-organ dysfunction and in uterus lethality occurring in homozygous mSEL-1L-deficient mice. Here we show that mSEL-1L is highly expressed in pluripotent embryonic stem cells and multipotent neural stem cells (NSCs) but silenced in all mature neural derivatives (i.e. astrocytes, oligodendrocytes, and neurons) by mmu-miR-183. NSCs derived from homozygous mSEL-1L-deficient embryos (mSEL-1L−/− NSCs) fail to proliferate in vitro, show a drastic reduction of the Notch effector HES-5, and reveal a significant down-modulation of the early neural progenitor markers PAX-6 and OLIG-2, when compared with the wild type (mSEL-1L+/+ NSCs) counterpart. Furthermore, these cells are almost completely deprived of the neural marker Nestin, display a significant decrease of SOX-2 expression, and rapidly undergo premature astrocytic commitment and apoptosis. The data suggest severe self-renewal defects occurring in these cells probably mediated by misregulation of the Notch signaling. The results reported here denote mSEL-1L as a primitive marker with a possible involvement in the regulation of neural progenitor stemness maintenance and lineage determination. PMID:21454627
Hao Huang; Xiao-Feng Zhao; Kang Zheng; Mengsheng Qiu
Axonal myelination is an essential process for normal functioning of the vertebrate central nervous system.Proper formation of myelin sheaths around axons depends on the timely differentiation of oligodendrocytes.This differentiation occurs on a predictable schedule both in culture and during development.However,the timing mechanisms for oligodendrocyte differentiation during normal development have not been fully uncovered.Recent studies have identified a large number of regulatory factors,including cell-intrinsic factors and extracellular signals,that could control the timing of oligodendrocyte differentiation.Here we provide a mechanistic and critical review of the timing control of oligodendrocyte differentiation.
Eva María Medina-Rodríguez
Full Text Available During development, oligodendrocytes are generated from oligodendrocyte precursor cells (OPCs, a cell type that is a significant proportion of the total cells (3-8% in the adult central nervous system (CNS of both rodents and humans. Adult OPCs are responsible for the spontaneous remyelination that occurs in demyelinating diseases like Multiple Sclerosis (MS and they constitute an interesting source of cells for regenerative therapy in such conditions. However, there is little data regarding the neurobiology of adult OPCs isolated from mice since an efficient method to isolate them has yet to be established. We have designed a protocol to obtain viable adult OPCs from the cerebral cortex of different mouse strains and we have compared its efficiency with other well-known methods. In addition, we show that this protocol is also useful to isolate functional OPCs from human brain biopsies. Using this method we can isolate primary cortical OPCs in sufficient quantities so as to be able to study their survival, maturation and function, and to facilitate an evaluation of their utility in myelin repair.
Full Text Available Since multiple sclerosis (MS is featured with widespread demyelination caused by autoimmune response, we investigated the recovery effects of F3.olig2 progenitors, established by transducing human neural stem cells (F3 NSCs with Olig2 transcription factor, in myelin oligodendrocyte glycoprotein- (MOG- induced experimental autoimmune encephalomyelitis (EAE model mice. Six days after EAE induction, F3 or F3.olig2 cells (1 × 106/mouse were intravenously transplanted. MOG-injected mice displayed severe neurobehavioral deficits which were remarkably attenuated and restored by cell transplantation, in which F3.olig2 cells were superior to its parental F3 cells. Transplanted cells migrated to the injured spinal cord, matured to oligodendrocytes, and produced myelin basic proteins (MBP. The F3.olig2 cells expressed growth and neurotrophic factors including brain-derived neurotrophic factor (BDNF, nerve growth factor (NGF, ciliary neurotrophic factor (CNTF, and leukemia inhibitory factor (LIF. In addition, the transplanted cells markedly attenuated inflammatory cell infiltration, reduced cytokine levels in the spinal cord and lymph nodes, and protected host myelins. The results indicate that F3.olig2 cells restore neurobehavioral symptoms of EAE mice by regulating autoimmune inflammatory responses as well as by stimulating remyelination and that F3.olig2 progenitors could be a candidate for the cell therapy of demyelinating diseases including MS.
Jing, J-H; Qian, J; Zhu, N; Chou, W-B; Huang, X-J
Oscillating field stimulation (OFS) has been used in attempts to treat spinal cord injury (SCI) and has been shown to improve remyelination after SCI in rats. However, some controversies regarding the effects of OFS have been presented in previous papers. Oligodendrocytes (OLs) are the main cell for remyelination and are derived from the differentiation of oligodendrocyte precursor cells (OPCs). To date, it has been unclear whether the differentiation of OPCs can be regulated by OFS. The goal of this study was to determine if OFS can improve the differentiation of OPCs and promote the recovery of neurological function after SCI in rats. Immature and mature OLs were observed in spinal cord slices through immunofluorescence staining. Levels of adenosine triphosphate (ATP) and the cytokine leukemia inhibitory factor (LIF) were detected by enzyme-linked immunosorbent assay (ELISA). Basso-Beattie-Bresnahan (BBB) scores and transcranial magnetic motor-evoked potentials (tcMMEPs) were used to evaluate the locomotor outcomes of rats after SCI. Our results showed a significant improvement in the differentiation of OPCs and the content of ATP and LIF in the injured spinal cord in the OFS group. Furthermore, BBB scores and tcMMEPs were significantly improved in the rats stimulated by OFS. These findings suggest that OFS can improve the differentiation of OPCs and promote the recovery of neurological function following SCI in rats. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.
Cheishvili, David; Maayan, Channa; Smith, Yoav; Ast, Gil; Razin, Aharon
The gene affected in the congenital neuropathy familial dysautonomia (FD) is IKBKAP that codes for the IKAP/hELP1 protein. Several different functions have been suggested for this protein, but none of them have been verified in vivo or shown to have some link with the FD phenotype. In an attempt to elucidate the involvement of IKAP/hELP1 in brain function, we searched for IKAP/hELP1 target genes associated with neuronal function. In a microarray expression analysis using RNA extracted from the cerebrum of two FD patients as well as sex and age matched controls, no genes were found to be upregulated in the FD cerebrum. However, 25 genes were downregulated more than 2-fold in the cerebrum of both the male FD child and female FD mature woman. Thirteen of them are known to be involved in oligodendrocyte development and myelin formation. The down regulation of all these genes was verified by real-time PCR. Four of these genes were also confirmed to be downregulated at the protein level. These results are statistically significant and have high biological relevance, since seven of the downregulated genes in the cerebrum of the FD patients were shown by others to be upregulated during oligodendrocyte differentiation in vitro. Our results therefore suggest that IKAP/hELP1 may play a role in oligodendrocyte differentiation and/or myelin formation.
de Vries, H; Hoekstra, D
Oligodendrocytes, the myelinating cells of the central nervous system, are capable of transporting vast quantities of proteins and of lipids, In particular galactosphingolipids, to the myelin sheath. The sheath is continuous with the plasma membrane of the oligodendrocyte, but the composition of bot
Arellano, Rogelio O; Sánchez-Gómez, María Victoria; Alberdi, Elena; Canedo-Antelo, Manuel; Chara, Juan Carlos; Palomino, Aitor; Pérez-Samartín, Alberto; Matute, Carlos
Myelination requires oligodendrocyte-neuron communication, and both neurotransmitters and contact interactions are essential for this process. Oligodendrocytes are endowed with neurotransmitter receptors whose expression levels and properties may change during myelination. However, only scant information is available about the extent and timing of these changes or how they are regulated by oligodendrocyte-neuron interactions. Here, we used electrophysiology to study the expression of ionotropic GABA, glutamate, and ATP receptors in oligodendrocytes derived from the optic nerve and forebrain cultured either alone or in the presence of dorsal root ganglion neurons. We observed that oligodendrocytes from both regions responded to these transmitters at 1 day in culture. After the first day in culture, however, GABA sensitivity diminished drastically to less than 10%, while that of glutamate and ATP remained constant. In contrast, the GABA response amplitude was sustained and remained stable in oligodendrocytes cocultured with dorsal root ganglion neurons. Immunochemistry and pharmacological properties of the responses indicated that they were mediated by distinctive GABAA receptors and that in coculture with neurons, the oligodendrocytes bearing the receptors were those in direct contact with axons. These results reveal that GABAA receptor regulation in oligodendrocytes is driven by axonal cues and that GABA signaling may play a role in myelination and/or during axon-glia recognition.
Mironova, Yevgeniya A; Lenk, Guy M; Lin, Jing-Ping; Lee, Seung Joon; Twiss, Jeffery L; Vaccari, Ilaria; Bolino, Alessandra; Havton, Leif A; Min, Sang H; Abrams, Charles S; Shrager, Peter; Meisler, Miriam H; Giger, Roman J
Proper development of the CNS axon-glia unit requires bi-directional communication between axons and oligodendrocytes (OLs). We show that the signaling lipid phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2] is required in neurons and in OLs for normal CNS myelination. In mice, mutations of Fig4, Pikfyve or Vac14, encoding key components of the PI(3,5)P2 biosynthetic complex, each lead to impaired OL maturation, severe CNS hypomyelination and delayed propagation of compound action potentials. Primary OLs deficient in Fig4 accumulate large LAMP1(+) and Rab7(+) vesicular structures and exhibit reduced membrane sheet expansion. PI(3,5)P2 deficiency leads to accumulation of myelin-associated glycoprotein (MAG) in LAMP1(+)perinuclear vesicles that fail to migrate to the nascent myelin sheet. Live-cell imaging of OLs after genetic or pharmacological inhibition of PI(3,5)P2 synthesis revealed impaired trafficking of plasma membrane-derived MAG through the endolysosomal system in primary cells and brain tissue. Collectively, our studies identify PI(3,5)P2 as a key regulator of myelin membrane trafficking and myelinogenesis.
Galvao, Rui Pedro; Kasina, Anita; McNeill, Robert S; Harbin, Jordan E; Foreman, Oded; Verhaak, Roel G W; Nishiyama, Akiko; Miller, C Ryan; Zong, Hui
How malignant gliomas arise in a mature brain remains a mystery, hindering the development of preventive and therapeutic interventions. We previously showed that oligodendrocyte precursor cells (OPCs) can be transformed into glioma when mutations are introduced perinatally. However, adult OPCs rarely proliferate compared with their perinatal counterparts. Whether these relatively quiescent cells have the potential to transform is unknown, which is a critical question considering the late onset of human glioma. Additionally, the premalignant events taking place between initial mutation and a fully developed tumor mass are particularly poorly understood in glioma. Here we used a temporally controllable Cre transgene to delete p53 and NF1 specifically in adult OPCs and demonstrated that these cells consistently give rise to malignant gliomas. To investigate the transforming process of quiescent adult OPCs, we then tracked these cells throughout the premalignant phase, which revealed a dynamic multistep transformation, starting with rapid but transient hyperproliferative reactivation, followed by a long period of dormancy, and then final malignant transformation. Using pharmacological approaches, we discovered that mammalian target of rapamycin signaling is critical for both the initial OPC reactivation step and late-stage tumor cell proliferation and thus might be a potential target for both glioma prevention and treatment. In summary, our results firmly establish the transforming potential of adult OPCs and reveal an actionable multiphasic reactivation process that turns slowly dividing OPCs into malignant gliomas.
Falcón-Urrutia, Paulina; Carrasco, Carlos M; Lois, Pablo; Palma, Veronica; Roth, Alejandro D
Primary Cilia (PC) are a very likely place for signal integration where multiple signaling pathways converge. Two major signaling pathways clearly shown to signal through the PC, Sonic Hedgehog (Shh) and PDGF-Rα, are particularly important for the proliferation and differentiation of oligodendrocytes, suggesting that their interaction occurs in or around this organelle. We identified PC in rat oligodendrocyte precursor cells (OPCs) and found that, while easily detectable in early OPCs, PC are lost as these cells progress to terminal differentiation. We confirmed the interaction between these pathways, as cyclopamine inhibition of Hedgehog function impairs both PDGF-mediated OPC proliferation and Shh-dependent cell branching. However, we failed to detect PDGF-Rα localization into the PC. Remarkably, ciliobrevin-mediated disruption of PC and reduction of OPC process extension was counteracted by recombinant Shh treatment, while PDGF had no effect. Therefore, while PDGF-Rα-dependent OPC proliferation and survival most probably does not initiate at the PC, still the integrity of this organelle and cilium-centered pathway is necessary for OPC survival and differentiation.
Eising, Else; de Leeuw, Christiaan; Min, Josine L; Anttila, Verneri; Verheijen, Mark Hg; Terwindt, Gisela M; Dichgans, Martin; Freilinger, Tobias; Kubisch, Christian; Ferrari, Michel D; Smit, August B; de Vries, Boukje; Palotie, Aarno; van den Maagdenberg, Arn Mjm; Posthuma, Danielle
Migraine is a common episodic brain disorder characterized by recurrent attacks of severe unilateral headache and additional neurological symptoms. Two main migraine types can be distinguished based on the presence of aura symptoms that can accompany the headache: migraine with aura and migraine without aura. Multiple genetic and environmental factors confer disease susceptibility. Recent genome-wide association studies (GWAS) indicate that migraine susceptibility genes are involved in various pathways, including neurotransmission, which have already been implicated in genetic studies of monogenic familial hemiplegic migraine, a subtype of migraine with aura. To further explore the genetic background of migraine, we performed a gene set analysis of migraine GWAS data of 4954 clinic-based patients with migraine, as well as 13,390 controls. Curated sets of synaptic genes and sets of genes predominantly expressed in three glial cell types (astrocytes, microglia and oligodendrocytes) were investigated. Our results show that gene sets containing astrocyte- and oligodendrocyte-related genes are associated with migraine, which is especially true for gene sets involved in protein modification and signal transduction. Observed differences between migraine with aura and migraine without aura indicate that both migraine types, at least in part, seem to have a different genetic background. © International Headache Society 2015.
Hopkinson, Branden M; Madsen, Claus Desler; Kalisz, Mark
of embryonic origin differentiating along the hepatic lineage. Our study reveals especially the transition between hepatic specification and hepatic maturation as dependent on mitochondrial respiration and demonstrates that even though differentiating cells are primarily dependent on glycolysis until induction...
Pang, Y; Campbell, L; Zheng, B; Fan, L; Cai, Z; Rhodes, P
Damage to oligodendrocyte (OL) progenitor cells (OPCs) and hypomyelination are two hallmark features of periventricular leukomalacia (PVL), the most common form of brain damage in premature infants. Clinical and animal studies have linked the incidence of PVL to maternal infection/inflammation, and activated microglia have been proposed to play a central role. However, the precise mechanism of how activated microglia adversely affects the survival and development of OPCs is still not clear. Here we demonstrate that lipopolysaccharide (LPS)-activated microglia are deleterious to OPCs, that is, impeding OL lineage progression, reducing the production of myelin basic protein (MBP), and mediating OPC death. We further demonstrate that LPS-activated microglia mediate OPC death by two distinct mechanisms in a time-dependent manner. The early phase of cell damage occurs within 24 h after LPS treatment, which is mediated by nitric oxide (NO)-dependent oxidative damage and is prevented by N(G)-nitro-l-arginine methyl ester (l-NAME), a general inhibitor of nitric oxide synthase. The delayed cell death is evident at 48 h after LPS treatment, is mediated by cytokines, and is prevented by blocking the activity of tumor necrosis factor-alpha (TNF-alpha) and pro-nerve growth factor (proNGF), but not by l-NAME. Furthermore, microglia-derived insulin-like growth factor-1 (IGF-1) and ciliary neurotrophic factor (CNTF) were significantly suppressed by LPS, and exogenous IGF-1 and CNTF synergistically protected OLs from death induced by LPS-treated microglia conditioned medium, indicating that a deficiency in trophic support may also be involved in OL death. Our finding that LPS-activated microglia not only induce two waves of cell death but also greatly impair OL development may shed some light on the mechanisms underlying selective white matter damage and hypomyelination in PVL.
Gordon, Deborah M; Pilko, Anna; De Bortoli, Nicolas; Ingram, Krista K
In dependent-lineage harvester ant populations, two lineages interbreed but are genetically distinct. The offspring of a male and queen of the same lineage are female reproductives; the offspring of a male and queen of different lineages are workers. Geographic surveys have shown asymmetries in the ratio of the two lineages in many harvester ant populations, which may be maintained by an ecological advantage to one of the lineages. Using census data from a long-term study of a dependent-lineage population of the red harvester ant, Pogonomyrmex barbatus, we identified the lineage of 130 colonies sampled in 1997-1999, ranging in age from 1 to 19 years when collected, and 268 colonies sampled in 2010, ranging in age from 1 to 28 years when collected. The ratio of lineages in the study population is similar across an 11-year interval, 0.59 J2 in 1999 and 0.66 J2 in 2010. The rare lineage, J1, had a slightly but significantly higher number of mates of the opposite lineage than the common lineage, J2, and, using data from previous work on reproductive output, higher male production. Mature colonies of the two lineages did not differ in nest mound size, foraging activity, or the propensity to relocate their nests. There were no strong differences in the relative recruitment or survivorship of the two lineages. Our results show no ecological advantage for either lineage, indicating that differences between the lineages in sex ratio allocation may be sufficient to maintain the current asymmetry of the lineage ratio in this population.
Substantial evidence supports autoimmune activity as the etiologic mechanism underlying multiple sclerosis (MS). Both the innate and the adaptive arms of the immune system are involved in the aberrant response to several antigens associated with the myelin sheath and oligodendrocytes (OGCs) after the activation of immune cells by self- or cross-reactive microbial pathogens. The CD4(+) Th1 cell, in particular, has been implicated, but it is abetted by a variety of other cell types (CD8(+) cells, B cells, macrophages, and microglia) and soluble products (proteases, cytokines, and nitric oxide [NO]) that act both outside of and within the CNS. This review describes recent and salient findings from animal models and human clinical studies that have established our current understanding of the distinct steps in the development of immune autoreactivity that culminates in the CNS lesions associated with MS.
Full Text Available NSC (neural stem cells/NPC (neural progenitor cells are multipotent and self-renew throughout adulthood in the SVZ (subventricular zone of the mammalian CNS (central nervous system. These cells are considered interesting targets for CNS neurodegenerative disorder cell therapies, and understanding their behaviour in vitro is crucial if they are to be cultured prior to transplantation. We cultured the SVZ tissue belonging to newborn rats under the form of NS (neurospheres to evaluate the effects of Tf (transferrin on cell proliferation. The NS were heterogeneous in terms of the NSC/NPC markers GFAP (glial fibrillary acidic protein, Nestin and Sox2 and the OL (oligodendrocyte progenitor markers NG2 (nerve/glia antigen 2 and PDGFRα (platelet-derived growth factor receptor α. The results of this study indicate that aTf (apoTransferrin is able to increase cell proliferation of SVZ-derived cells in vitro, and that these effects were mediated at least in part by the TfRc1 (Tf receptor 1. Since OPCs (oligodendrocyte progenitor cells represent a significant proportion of the proliferating cells in the SVZ-derived primary cultures, we used the immature OL cell line N20.1 to show that Tf was able to augment the proliferation rate of OPC, either by adding aTf to the culture medium or by overexpressing rat Tf in situ. The culture medium supplemented with ferric iron, together with aTf, increased the DNA content, while ferrous iron did not. The present work provides data that could have a potential application in human cell replacement therapies for neurodegenerative disease and/or CNS injury that require the use of in vitro amplified NPCs.
XinhuaHu; LuJin; LinyinFeng
Neurotrophin 3 (NT3) induces mouse cortical stem cells to an asymmetric division from a symmetric division, suggesting that NT3 may work as an early differentiative signal for neural stem cells (NSCs). Here, using cultured post-natal hippocampal stem cells as a model, we demonstrated that NT3-stimulation causes NSCs to differentiate into oligodendrocyte precursors (OLPs) through an extracellular signal-related kinasel/2 (Erkl/2)-dependent pathway. Following the treatment of NT3 for 24h, NSCs differentiated into more OLPs and fewer neurons, whereas the proliferation and survival of OLPs were not affected. NT3 induced a series of intracellular responses including enhancement of phosphorylation of Erk 1/2 or Akt and increase of expression of oligodendrocyte lineage gene (Olig)-1, a transcriptional factor known to participate in oligodendrocyte development. Application of U0126, a specific inhibitor of MEK1/2 which are upstream to Erk1/2, blocked the phosphorylation of Erk1/2, suppressed the expression of Olig-1 and prevented NSC differentiation into OLPs in response to NT3 stimulation. Blockade of TrkC also inhibited the differentiation of NSCs to OLPs induced by NT3. However,administration of LY294002, an inhibitor of phosphatidylinositol 3 kinase (PI3K), blocked the phosphorylation of Akt but did not affect the effect of NT3 on the expression of Olig-1 and on NSC differentiation into OLPs. Taken together, these results suggest that NT3 induce NSCs to differentiate into OLPs by enhancing the expression of Olig-1 through an Erk1/2-dependent pathway.
Protective Effect of Electroacupuncture on Neural Myelin Sheaths is Mediated via Promotion of Oligodendrocyte Proliferation and Inhibition of Oligodendrocyte Death After Compressed Spinal Cord Injury.
Huang, Siqin; Tang, Chenglin; Sun, Shanquan; Cao, Wenfu; Qi, Wei; Xu, Jin; Huang, Juan; Lu, Weitian; Liu, Qian; Gong, Biao; Zhang, Yi; Jiang, Jin
Electroacupuncture (EA) has been used worldwide to treat demyelinating diseases, but its therapeutic mechanism is poorly understood. In this study, a custom-designed model of compressed spinal cord injury (CSCI) was used to induce demyelination. Zusanli (ST36) and Taixi (KI3) acupoints of adult rats were stimulated by EA to demonstrate its protective effect. At 14 days after EA, both locomotor skills and ultrastructural features of myelin sheath were significantly improved. Phenotypes of proliferating cells were identified by double immunolabeling of 5-ethynyl-2'-deoxyuridine with antibodies to cell markers: NG2 [oligodendrocyte precursor cell (OPC) marker], 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase) (oligodendrocyte marker), and glial fibrillary acidic protein (GFAP) (astrocyte marker). EA enhanced the proliferation of OPCs and CNPase, as well as the differentiation of OPCs by promoting Olig2 (the basic helix-loop-helix protein) and attenuating Id2 (the inhibitor of DNA binding 2). EA could also improve myelin basic protein (MBP) and protect existing oligodendrocytes from apoptosis by inhibiting caspase-12 (a representative of endoplasmic reticulum stress) and cytochrome c (an apoptotic factor and hallmark of mitochondria). Therefore, our results indicate that the protective effect of EA on neural myelin sheaths is mediated via promotion of oligodendrocyte proliferation and inhibition of oligodendrocyte death after CSCI.
Full Text Available The aging-induced decrease in axonal myelination/remyelination is due to impaired recruitment and differentiation of oligodendrocyte progenitor cells (OPCs. Our previous studies have shown that a monoclonal antibody to DEAD (Asp-Glu-Ala-Asp box polypeptide 54 (Ddx54, a member of the DEAD box family of RNA helicases, (1 specifically labels oligodendrocyte lineages, (2 binds to mRNA and protein isoforms of myelin basic proteins (MBP, and (3 regulates migration of OPCs from ventricular zone to corpus callosum in mice. It has also been demonstrated that specific loss of a 21.5 kDa MBP isoform (MBP21.5 reflects demyelination status, and oral administration of an extract of Chinpi, citrus unshiu peel, reversed the aging-induced demyelination. Here, we report that Chinpi treatment induced a specific increase in the MBP21.5, led to the reappearance of Ddx54-expressing cells in ventricular-subventricular zone and corpus callosum of aged mice, and promoted remyelination. Treatment of in vitro OPC cultures with Chinpi constituents, hesperidin plus narirutin, led to an increase in 5-bromo-2′-deoxyuridine incorporation in Ddx54-expressing OPCs, but not in NG2- or Olig2-expressing cell populations. The present study suggests that Ddx54 plays crucial role in remyelination. Furthermore, Chinpi and Chinpi-containing herbal medicines may be a therapeutic option for the aging-induced demyelination diseases.
Magri, Laura; Swiss, Victoria A.; Jablonska, Beata; Lei, Liang; Pedre, Xiomara; Walsh, Martin; Zhang, Weijia; Gallo, Vittorio; Canoll, Peter
Cell cycle exit is an obligatory step for the differentiation of oligodendrocyte progenitor cells (OPCs) into myelinating cells. A key regulator of the transition from proliferation to quiescence is the E2F/Rb pathway, whose activity is highly regulated in physiological conditions and deregulated in tumors. In this paper we report a lineage-specific decline of nuclear E2F1 during differentiation of rodent OPC into oligodendrocytes (OLs) in developing white matter tracts and in cultured cells. Using chromatin immunoprecipitation (ChIP) and deep-sequencing in mouse and rat OPCs, we identified cell cycle genes (i.e., Cdc2) and chromatin components (i.e., Hmgn1, Hmgn2), including those modulating DNA methylation (i.e., Uhrf1), as E2F1 targets. Binding of E2F1 to chromatin on the gene targets was validated and their expression assessed in developing white matter tracts and cultured OPCs. Increased expression of E2F1 gene targets was also detected in mouse gliomas (that were induced by retroviral transformation of OPCs) compared with normal brain. Together, these data identify E2F1 as a key transcription factor modulating the expression of chromatin components in OPC during the transition from proliferation to differentiation. PMID:24453336
Angelo H All
Full Text Available BACKGROUND: Transplantations of human stem cell derivatives have been widely investigated in rodent models for the potential restoration of function of neural pathways after spinal cord injury (SCI. Studies have already demonstrated cells survival following transplantation in SCI. We sought to evaluate survival and potential therapeutic effects of transplanted human embryonic stem (hES cell-derived oligodendrocyte progenitor cells (OPCs in a contusive injury in rats. Bioluminescence imaging was utilized to verify survivability of cells up to 4 weeks, and somatosensory evoked potential (SSEPs were recorded at the cortex to monitor function of sensory pathways throughout the 6-week recovery period. PRINCIPAL FINDINGS: hES cells were transduced with the firefly luciferase gene and differentiated into OPCs. OPCs were transplanted into the lesion epicenter of rat spinal cords 2 hours after inducing a moderate contusive SCI. The hES-treatment group showed improved SSEPs, including increased amplitude and decreased latencies, compared to the control group. The bioluminescence of transplanted OPCs decreased by 97% in the injured spinal cord compared to only 80% when injected into an uninjured spinal cord. Bioluminescence increased in both experimental groups such that by week 3, no statistical difference was detected, signifying that the cells survived and proliferated independent of injury. Post-mortem histology of the spinal cords showed integration of human cells expressing mature oligodendrocyte markers and myelin basic protein without the expression of markers for astrocytes (GFAP or pluripotent cells (OCT4. CONCLUSIONS: hES-derived OPCs transplanted 2 hours after contusive SCI survive and differentiate into OLs that produce MBP. Treated rats demonstrated functional improvements in SSEP amplitudes and latencies compared to controls as early as 1 week post-injury. Finally, the hostile injury microenvironment at 2 hours post-injury initially caused
de Vries, H; Hoekstra, D
Oligodendrocytes, the myelinating cells of the central nervous system, are capable of transporting vast quantities of proteins and of lipids, in particular galactosphingolipids, to the myelin sheath. The sheath is continuous with the plasma membrane of the oligodendrocyte, but the composition of both membrane domains differs substantially. Given its high glycosphingolipid and cholesterol content the myelin sheath bears similarity to the lipid composition of the apical domain of a polarized cell. The question thus arises whether myelin components, like typical apical membrane proteins are transported by an apical-like trafficking mechanism to the sheath, involving a 'raft'-mediated mechanism. Indeed, the evidence indicates the presence of cognate apical and basolateral pathways in oligodendrocytes. However, all major myelin proteins do not participate in this pathway, and remarkably apical-like trafficking seems to be restricted to the oligodendrocyte cell body. In this review, we summarize the evidence on the existence of different trafficking pathways in the oligodendrocyte, and discuss possible mechanisms separating the oligodendrocyte's membrane domains.
Butt, A M; Ibrahim, M; Berry, M
Axon-oligodendrocyte relations of Rip-immunolabelled and dye-injected oligodendrocyte units are characterised in the adult rat anterior medullary velum (AMV). Each oligodendrocyte unit comprised the oligodendrocyte cell body, processes and the internodal myelin segments they support. Oligodendrocyte units corresponded to classically described type I/II or type III/IV unit phenotypes which respectively myelinated discrete populations of small and large diameter axons, delineated by a myelinated fire diameter of 2-4 microns (diameter of the axon plus its myelin sheath). Within units, mean fibre diameter was directly related to mean internodal length and inversely related to the number of myelin sheaths in the unit. The relationship between fibre diameter and internodal length was retained in units which myelinated axons of different diameters, indicating that axon diameter was an important determinant of the longitudinal dimensions of myelin sheaths. We also show that type III/IV units maintained a far greater volume of myelin than type I/II units. It was concluded that type I/II and III/IV oligodendrocytes represent two functionally and morphologically distinct phenotypes whose distribution densities were determined by the diameter and spatial dispersion of axons.
Briney, Bryan; Le, Khoa; Zhu, Jiang; Burton, Dennis R
Defining the dynamics and maturation processes of antibody clonal lineages is crucial to understanding the humoral response to infection and immunization. Although individual antibody lineages have been previously analyzed in isolation, these studies provide only a narrow view of the total antibody response. Comprehensive study of antibody lineages has been limited by the lack of an accurate clonal lineage assignment algorithm capable of operating on next-generation sequencing datasets. To address this shortcoming, we developed Clonify, which is able to perform unseeded lineage assignment on very large sets of antibody sequences. Application of Clonify to IgG+ memory repertoires from healthy individuals revealed a surprising lack of influence of large extended lineages on the overall repertoire composition, indicating that this composition is driven less by the order and frequency of pathogen encounters than previously thought. Clonify is freely available at www.github.com/briney/clonify-python.
Naruse, Masae; Shibasaki, Koji; Ishizaki, Yasuki, E-mail: email@example.com
The origins and developmental regulation of cerebellar oligodendrocytes are largely unknown, although some hypotheses of embryonic origins have been suggested. Neural stem cells exist in the white matter of postnatal cerebellum, but it is unclear whether these neural stem cells generate oligodendrocytes at postnatal stages. We previously showed that cerebellar progenitor cells, including neural stem cells, widely express CD44 at around postnatal day 3. In the present study, we showed that CD44-positive cells prepared from the postnatal day 3 cerebellum gave rise to neurospheres, while CD44-negative cells prepared from the same cerebellum did not. These neurospheres differentiated mainly into oligodendrocytes and astrocytes, suggesting that CD44-positive neural stem/progenitor cells might generate oligodendrocytes in postnatal cerebellum. We cultured CD44-positive cells from the postnatal day 3 cerebellum in the presence of signaling molecules known as mitogens or inductive differentiation factors for oligodendrocyte progenitor cells. Of these, only FGF-2 promoted survival and proliferation of CD44-positive cells, and these cells differentiated into O4+ oligodendrocytes. Furthermore, we examined the effect of FGF-2 on cerebellar oligodendrocyte development ex vivo. FGF-2 enhanced proliferation of oligodendrocyte progenitor cells and increased the number of O4+ and CC1+ oligodendrocytes in slice cultures. These results suggest that CD44-positive cells might be a source of cerebellar oligodendrocytes and that FGF-2 plays important roles in their development at an early postnatal stage. - Highlights: • CD44 is expressed in cerebellar neural stem/progenitor cells at postnatal day 3 (P3). • FGF-2 promoted proliferation of CD44-positive progenitor cells from P3 cerebellum. • FGF-2 promoted oligodendrocytic differentiation of CD44-positive progenitor cells. • FGF-2 increased the number of oligodendrocytes in P3 cerebellar slice culture.
Domercq, Maria; Alberdi, Elena; Sánchez-Gómez, Maria Victoria; Ariz, Usue; Pérez-Samartín, Alberto; Matute, Carlos
Oligodendrocytes, the myelinating cells of the CNS, are highly vulnerable to glutamate excitotoxicity, a mechanism involved in tissue damage in multiple sclerosis. Thus, understanding oligodendrocyte death at the molecular level is important to develop new therapeutic approaches to treat the disease. Here, using microarray analysis and quantitative PCR, we observed that dual-specific phosphatase-6 (Dusp6), an extracellular regulated kinase-specific phosphatase, is up-regulated in oligodendrocyte cultures as well as in optic nerves after AMPA receptor activation. In turn, Dusp6 is overexpressed in optic nerves from multiple sclerosis patients before the appearance of evident damage in this structure. We further analyzed the role of Dusp6 and ERK signaling in excitotoxic oligodendrocyte death and observed that AMPA receptor activation induces a rapid increase in ERK1/2 phosphorylation. Blocking Dusp6 expression, which enhances ERK1/2 phosphorylation, significantly diminished AMPA receptor-induced oligodendrocyte death. In contrast, MAPK/ERK pathway inhibition with UO126 significantly potentiates excitotoxic oligodendrocyte death and increases cytochrome c release, mitochondrial depolarization, and mitochondrial calcium overload produced by AMPA receptor stimulation. Upstream analysis demonstrated that MAPK/ERK signaling alters AMPA receptor properties. Indeed, Dusp6 overexpression as well as incubation with UO126 produced an increase in AMPA receptor-induced inward currents and cytosolic calcium overload. Together, these data suggest that levels of phosphorylated ERK, controlled by Dusp6 phosphatase, regulate glutamate receptor permeability and oligodendroglial excitotoxicity. Therefore, targeting Dusp6 may be a useful strategy to prevent oligodendrocyte death in multiple sclerosis and other diseases involving CNS white matter. PMID:21300799
Li He; Q.Richard Lu
Oligodendrocytes,the myelin-forming cells for axon ensheathment in the central nervous system,are critical for maximizing and maintaining the conduction velocity of nerve impulses and proper brain function.Demyelination caused by injury or disease together with failure of myelin regeneration disrupts the rapid propagation of action potentials along nerve fibers,and is associated with acquired and inherited disorders,including devastating multiple sclerosis and leukodystrophies.The molecular mechanisms of oligodendrocyte myelination and remyelination remain poorly understood.Recently,a series of signaling pathways including Shh,Notch,BMP and Wnt signaling and their intracellular effectors such as Olig1/2,Hes1/5,Smads and TCFs,have been shown to play important roles in regulating oligodendrocyte development and myelination.In this review,we summarize our recent understanding of how these signaling pathways modulate the progression of oligodendrocyte specification and differentiation in a spatiotemporally-specific manner.A better understanding of the complex but coordinated function of extracellular signals and intracellular determinants during oligodendrocyte development will help to devise effective strategies to promote myelin repair for patients with demyelinating diseases.
Yin, Wu; Hu, Bing
Demyelinating diseases include multiple sclerosis, which is a neurodegenerative disease characterized by immune attacks on the central nervous system (CNS), resulting in myelin sheath damage and axonal loss. Leucine-rich repeat and immunoglobulin domain-containing neurite outgrowth inhibitory protein (Nogo) receptor-interacting protein-1 (LINGO-1) have been identified as a negative regulator of oligodendrocytes differentiation. Targeted LINGO-1 inhibition promotes neuron survival, axon regeneration, oligodendrocyte differentiation, and remyelination in diverse animal models. Although studies in rodent models have extended our understanding of LINGO-1, its roles in neural development and myelination in zebrafish (Danio rerio) are not yet clear. In this study, we cloned the zebrafish homolog of the human LINGO-1 and found that lingo1b regulated myelination and oligodendrocyte differentiation. The expression of lingo1b started 1 (mRNA) and 2 (protein) days post-fertilization (dpf) in the CNS. Morpholino oligonucleotide knockdown of lingo1b resulted in developmental abnormalities, including less dark pigment, small eyes, and a curly spinal cord. The lack of lingo1b enhanced myelination and oligodendrocyte differentiation during embryogenesis. Furthermore, immunohistochemistry and movement analysis showed that lingo1b was involved in the axon development of primary motor neurons. These results suggested that Lingo1b protein functions as a negative regulator of myelination and oligodendrocyte differentiation during zebrafish development.
Venkatesh, Katari; Srikanth, Lokanathan; Vengamma, Bhuma; Chandrasekhar, Chodimella; Prasad, Bodapati Chandra Mouleshwara; Sarma, Potukuchi Venkata Gurunadha Krishna
The extent of myelination on the axon promotes transmission of impulses in the neural network, any disturbances in this process results in the neurodegenerative condition. Transplantation of oligodendrocyte precursors that supports in the regeneration of axons through myelination is an important step in the restoration of damaged neurons. Therefore, in the present study, the differentiation of human CD34+ stem cells into oligodendrocytes was carried out. The pure human CD34+ culture developed from the stem cells obtained from a peripheral blood of a donor were subjected to oligodendrocyte differentiation medium (ODM). The ODM at a concentration of 40ng/ml thyroxine, 40ng/ml 3,3',5-tri-iodo-thyronine showed distinct morphological changes from day 6 to 9 with cells exhibiting conspicuous stellate morphology and extensive foot processes. The real-time PCR analysis showed prominent expression of Olig2, CNPase, PDGFRα and PLP1/DM20 in the differentiated cells confirming the formed cells are oligodendrocyte precursors. The expression of these genes increased from days 6 to 9 corresponding to the morphological changes observed with almost no expression of GFAP+ cells. The distinct CNPase activity was observed in these differentiated cells compared to normal CD34+ stem cells correlating with results of real-time PCR conclusively explains the development of oligodendrocytes from human CD34+ stem cells.
González-Fernández, Estíbaliz; Sánchez-Gómez, María Victoria; Pérez-Samartín, Alberto; Arellano, Rogelio O; Matute, Carlos
Adenosine receptor activation is involved in myelination and in apoptotic pathways linked to neurodegenerative diseases. In this study, we investigated the effects of adenosine receptor activation in the viability of oligodendrocytes of the rat optic nerve. Selective activation of A3 receptors in pure cultures of oligodendrocytes caused concentration-dependent apoptotic and necrotic death which was preceded by oxidative stress and mitochondrial membrane depolarization. Oligodendrocyte apoptosis induced by A3 receptor activation was caspase-dependent and caspase-independent. In addition to dissociated cultures, incubation of optic nerves ex vivo with adenosine and the A3 receptor agonist 2-CI-IB-MECA(1-[2-Chloro-6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-1-deoxy-N-methyl-b-D-ribofuranuronamide)-induced caspase-3 activation, oligodendrocyte damage, and myelin loss, effects which were prevented by the presence of caffeine and the A3 receptor antagonist MRS 1220 (N-[9-Chloro-2-(2-furanyl)[1,2,4]-triazolo [1,5-c]quinazolin-5-yl]benzene acetamide). Finally, ischemia-induced injury and functional loss to the optic nerve was attenuated by blocking A3 receptors. Together, these results indicate that adenosine may trigger oligodendrocyte death via activation of A3 receptors and suggest that this mechanism contributes to optic nerve and white matter ischemic damage.
Rinholm, Johanne E; Vervaeke, Koen; Tadross, Michael R; Tkachuk, Ariana N; Kopek, Benjamin G; Brown, Timothy A; Bergersen, Linda H; Clayton, David A
Mitochondria play several crucial roles in the life of oligodendrocytes. During development of the myelin sheath they are essential providers of carbon skeletons and energy for lipid synthesis. During normal brain function their consumption of pyruvate will be a key determinant of how much lactate is available for oligodendrocytes to export to power axonal function. Finally, during calcium-overload induced pathology, as occurs in ischemia, mitochondria may buffer calcium or induce apoptosis. Despite their important functions, very little is known of the properties of oligodendrocyte mitochondria, and mitochondria have never been observed in the myelin sheaths. We have now used targeted expression of fluorescent mitochondrial markers to characterize the location and movement of mitochondria within oligodendrocytes. We show for the first time that mitochondria are able to enter and move within the myelin sheath. Within the myelin sheath the highest number of mitochondria was in the cytoplasmic ridges along the sheath. Mitochondria moved more slowly than in neurons and, in contrast to their behavior in neurons and astrocytes, their movement was increased rather than inhibited by glutamate activating NMDA receptors. By electron microscopy we show that myelin sheath mitochondria have a low surface area of cristae, which suggests a low ATP production. These data specify fundamental properties of the oxidative phosphorylation system in oligodendrocytes, the glial cells that enhance cognition by speeding action potential propagation and provide metabolic support to axons. © 2016 Wiley Periodicals, Inc.
Nielsen, Helle Hvilsted; Ladeby, Rune; Drøjdahl, Nina;
Proliferation of the adult NG2-expressing oligodendrocyte precursor cells has traditionally been viewed as a remyelination response ensuing from destruction of myelin and oligodendrocytes, and not to the axonal pathology that is also a characteristic of demyelinating disease. To better understand...... the response of the NG2+ cells to the different components of demyelinating pathology, we investigated the response of adult NG2+ cells to axonal degeneration in the absence of primary myelin or oligodendrocyte pathology. Axonal degeneration was induced in the hippocampal dentate gyrus of adult mice...... by transection of the entorhino-dentate perforant path projection. The acutely induced degeneration of axons and terminals resulted in a prompt response of NG2+ cells, consisting of morphological transformation, cellular proliferation, and upregulation of NG2 expression days 2-3 after surgery. This was followed...
Domingues, Helena S.; Portugal, Camila C.; Socodato, Renato; Relvas, João B.
Oligodendrocytes are the myelinating glia of the central nervous system. Myelination of axons allows rapid saltatory conduction of nerve impulses and contributes to axonal integrity. Devastating neurological deficits caused by demyelinating diseases, such as multiple sclerosis, illustrate well the importance of the process. In this review, we focus on the positive and negative interactions between oligodendrocytes, astrocytes, and microglia during developmental myelination and remyelination. Even though many lines of evidence support a crucial role for glia crosstalk during these processes, the nature of such interactions is often neglected when designing therapeutics for repair of demyelinated lesions. Understanding the cellular and molecular mechanisms underlying glial cell communication and how they influence oligodendrocyte differentiation and myelination is fundamental to uncover novel therapeutic strategies for myelin repair. PMID:27551677
Kwon, Heung Sun; Nakaya, Naoki; Abu-Asab, Mones; Kim, Hong Sug; Tomarev, Stanislav I
Myocilin is a secreted glycoprotein that belongs to a family of olfactomedin domain-containing proteins. Although myocilin is detected in several ocular and nonocular tissues, the only reported human pathology related to mutations in the MYOCILIN gene is primary open-angle glaucoma. Functions of myocilin are poorly understood. Here we demonstrate that myocilin is a mediator of oligodendrocyte differentiation and is involved in the myelination of the optic nerve in mice. Myocilin is expressed and secreted by optic nerve astrocytes. Differentiation of optic nerve oligodendrocytes is delayed in Myocilin-null mice. Optic nerves of Myocilin-null mice contain reduced levels of several myelin-associated proteins including myelin basic protein, myelin proteolipid protein, and 2'3'-cyclic nucleotide 3'-phosphodiesterase compared with those of wild-type littermates. This leads to reduced myelin sheath thickness of optic nerve axons in Myocilin-null mice compared with wild-type littermates, and this difference is more pronounced at early postnatal stages compared with adult mice. Myocilin also affects differentiation of oligodendrocyte precursors in vitro. Its addition to primary cultures of differentiating oligodendrocyte precursors increases levels of tested markers of oligodendrocyte differentiation and stimulates elongation of oligodendrocyte processes. Myocilin stimulation of oligodendrocyte differentiation occurs through the NgR1/Lingo-1 receptor complex. Myocilin physically interacts with Lingo-1 and may be considered as a Lingo-1 ligand. Myocilin-induced elongation of oligodendrocyte processes may be mediated by activation of FYN and suppression of RhoA GTPase.
Chesik, Daniel; De Keyser, Jacques; Bron, Reinier; Fuhler, Gwenny M.
P>In multiple sclerosis (MS), oligodendrocytes in lesions are lost, leaving damaged tissue virtually devoid of these myelin-producing cells. Our group has recently demonstrated enhanced expression of insulin-like growth factor (IGF) binding protein-1 (IGFBP-1) in oligodendrocytes (CNPase+) localized
Bijlard, Marjolein; Klunder, Lammert; de Jonge, Jenny C.; Nomden, Anita; Tyagi, Sanjay; de Vries, Hans; Hoekstra, Dick; Baron, Wia
Myelination of axons by oligodendrocytes is essential for saltatory nerve conduction. To form myelin membranes, a coordinated synthesis and subsequent polarized transport of myelin components are necessary. Here, we show that as part of the mechanism to establish membrane polarity, oligodendrocytes
Cho, S S; Lucas, J J
We have investigated immunocytochemically the localization of a transferrin binding protein (TfBP) in adult CNS of avian and mammalian species using a polyclonal antibody raised against the protein purified from hen oviduct membranes (alpha OV-TfBP). TfBP has recently been shown to be HSP108. An overall strong immunoreactivity was revealed in most parts of the avian brains, especially in the white matter. The main immunoreactivity originated in small, intensely reacting cells interpreted as oligodendrocytes. The density of TfBP-labeled oligodendrocytes of the avian brains was generally proportional to the degree of myelination. There were no marked differences in TfBP-immunostaining pattern between avian species (chick, pigeon and lovebird). On the other hand, in rat, rabbit and cat brains we could not find any TfBP-immunoreactivity. Immunoelectron microscopy has further revealed that TfBP is present in the light and medium types of oligodendrocytes which are known to have high metabolic activities. TfBP reaction product was homogeneously dispersed throughout the perinuclear cytoplasm and fine processes of oligodendrocytes. The intracytoplasmic organelles such as mitochondria and Golgi apparatus were devoid of reaction product. The presence of TfBP in oligodendrocytes implies that this protein may play an important role in transferrin-mediated iron metabolism in the CNS. The complete lack of cross-reactivity between alpha OV-TfBP and mammalian tissues suggests that there is species variability in TfBP structure. We conclude that this chick TfBP antiserum will prove useful in studies of oligodendrocytes and myelination in the avian CNS.
Lee, Jee Y; Kang, So R; Yune, Tae Y
Oligodendrocyte cell death and axon demyelination after spinal cord injury (SCI) are known to be important secondary injuries contributing to permanent neurological disability. Thus, blocking oligodendrocyte cell death should be considered for therapeutic intervention after SCI. Here, we demonstrated that fluoxetine, an antidepressant drug, alleviates oligodendrocyte cell death by inhibiting microglia activation after SCI. After injury at the T9 level with a Precision Systems and Instrumentation (Lexington, KY) device, fluoxetine (10 mg/kg, intraperitoneal) was administered once a day for the indicated time points. Immunostaining with CD11b (OX-42) antibody and quantification analysis showed that microglia activation was significantly inhibited by fluoxetine at 5 days after injury. Fluoxetine also significantly inhibited activation of p38 mitogen-activated protein kinase (p38-MAPK) and expression of pro-nerve growth factor (pro-NGF), which is known to mediate oligodendrocyte cell death through the p75 neurotrophin receptor after SCI. In addition, fluoxetine attenuated activation of Ras homolog gene family member A and decreased the level of phosphorylated c-Jun and, ultimately, alleviated caspase-3 activation and significantly reduced cell death of oligodendrocytes at 5 days after SCI. Further, the decrease of myelin basic protein, myelin loss, and axon loss in white matter was also significantly blocked by fluoxetine, as compared to vehicle control. These results suggest that fluoxetine inhibits oligodendrocyte cell death by inhibiting microglia activation and p38-MAPK activation, followed by pro-NGF production after SCI, and provide a potential usage of fluoxetine for a therapeutic agent after acute SCI in humans.
Lee, Xinhua; Shao, Zhaohui; Sheng, Guoqing; Pepinsky, Blake; Mi, Sha
Oligodendrocyte differentiation is negatively regulated by LINGO-1 and positively regulated by the ErbB2 receptor tyrosine kinase. In wild-type oligodendrocytes, inhibition of ErbB2 blocks differentiation, whereas activation of ErbB2 promotes differentiation. In LINGO-1(-/-) oligodendrocytes, inhibition of ErbB2 blocks oligodendrocyte differentiation; whereas activation of ErbB2 does not enhance differentiation. Biological and biochemical evidence showing that LINGO-1 can directly bind to ErbB2, block ErbB2 translocation into lipid rafts, and inhibit its phosphorylation for activation. The study demonstrates a novel regulatory mechanism of ErbB2 function whereby LINGO-1 suppresses oligodendrocyte differentiation by inhibiting ErbB2 translocation and activation in lipid rafts.
Ben W. Dulken
Full Text Available Neural stem cells (NSCs in the adult mammalian brain serve as a reservoir for the generation of new neurons, oligodendrocytes, and astrocytes. Here, we use single-cell RNA sequencing to characterize adult NSC populations and examine the molecular identities and heterogeneity of in vivo NSC populations. We find that cells in the NSC lineage exist on a continuum through the processes of activation and differentiation. Interestingly, rare intermediate states with distinct molecular profiles can be identified and experimentally validated, and our analysis identifies putative surface markers and key intracellular regulators for these subpopulations of NSCs. Finally, using the power of single-cell profiling, we conduct a meta-analysis to compare in vivo NSCs and in vitro cultures, distinct fluorescence-activated cell sorting strategies, and different neurogenic niches. These data provide a resource for the field and contribute to an integrative understanding of the adult NSC lineage.
Full Text Available BACKGROUND: Granulocyte colony-stimulating factor (G-CSF is a protein that stimulates differentiation, proliferation, and survival of cells in the granulocytic lineage. Recently, a neuroprotective effect of G-CSF was reported in a model of cerebral infarction and we previously reported the same effect in studies of murine spinal cord injury (SCI. The aim of the present study was to elucidate the potential therapeutic effect of G-CSF for SCI in rats. METHODS: Adult female Sprague-Dawley rats were used in the present study. Contusive SCI was introduced using the Infinite Horizon Impactor (magnitude: 200 kilodyne. Recombinant human G-CSF (15.0 µg/kg was administered by tail vein injection at 1 h after surgery and daily the next four days. The vehicle control rats received equal volumes of normal saline at the same time points. RESULTS: Using a contusive SCI model to examine the neuroprotective potential of G-CSF, we found that G-CSF suppressed the expression of pro-inflammatory cytokine (IL-1 beta and TNF- alpha in mRNA and protein levels. Histological assessment with luxol fast blue staining revealed that the area of white matter spared in the injured spinal cord was significantly larger in G-CSF-treated rats. Immunohistochemical analysis showed that G-CSF promoted up-regulation of anti-apoptotic protein Bcl-Xl on oligpodendrocytes and suppressed apoptosis of oligodendrocytes after SCI. Moreover, administration of G-CSF promoted better functional recovery of hind limbs. CONCLUSIONS: G-CSF protects oligodendrocyte from SCI-induced cell death via the suppression of inflammatory cytokines and up-regulation of anti-apoptotic protein. As a result, G-CSF attenuates white matter loss and promotes hindlimb functional recovery.
Chen, Keren; Ong, William; Chew, Sing Yian; Liu, Quan
Neurological diseases are one of the leading causes of adult disability and they are estimated to cause more deaths than cancer in the elderly population by 2040. Stem cell therapy has shown great potential in treating neurological diseases. However, before cell therapy can be widely adopted in the long term, a number of challenges need to be addressed, including the fundamental research about cellular development of neural progenitor cells. To facilitate the fundamental research of neural progenitor cells, many methods have been developed to identify neural progenitor cells. Although great progress has been made, there is still lack of an effective method to achieve fast, label-free and noninvasive differentiation of neural progenitor cells and their lineages. As a fast, label-free and noninvasive technique, spontaneous Raman spectroscopy has been conducted to characterize many types of stem cells including neural stem cells. However, to our best knowledge, it has not been studied for the discrimination of neural progenitor cells from specific lineages. Here we report the differentiation of neural progenitor cell from their lineages including astrocytes, oligodendrocytes and neurons using spontaneous Raman spectroscopy. Moreover, we also evaluate the influence of system parameters during spectral acquisition on the quality of measured Raman spectra and the accuracy of classification using the spectra, which yield a set of optimal system parameters facilitating future studies.
Orduz, David; Maldonado, Paloma P; Balia, Maddalena; Vélez-Fort, Mateo; de Sars, Vincent; Yanagawa, Yuchio; Emiliani, Valentina; Angulo, Maria Cecilia
NG2 cells, oligodendrocyte progenitors, receive a major synaptic input from interneurons in the developing neocortex. It is presumed that these precursors integrate cortical networks where they act as sensors of neuronal activity. We show that NG2 cells of the developing somatosensory cortex form a
Balasubramaniyan, [No Value; Timmer, N; Kust, B; Boddeke, E; Copray, S
In order to develop an efficient strategy to induce the in vitro differentiation of neural stem cells (NSCs) into oligodendrocyte progenitor cells (OPCs), NSCs were isolated from E14 mice and grown in medium containing epidermal growth factor and fibroblast growth factor (FGF). Besides supplementing
Juliana Silva Cassoli
Full Text Available Separate lines of evidence have demonstrated the involvement of NMDA receptor and oligodendrocyte dysfunctions in schizophrenia. Here we have carried out shotgun mass spectrometry proteome analysis of oligodendrocytes treated with the NMDA receptor antagonist MK-801 to gain potential insights into these effects at the molecular level. The MK-801 treatment led to alterations in the levels of 68 proteins, which are associated with seven distinct biological processes. Most of these proteins are involved in energy metabolism and many have been found to be dysregulated in previous proteomic studies of post-mortem brain tissues from schizophrenia patients. Finally, addition of the antipsychotic clozapine to MK-801-treated oligodendrocyte cultures resulted in changes in the levels of 45 proteins and treatment with clozapine alone altered 122 proteins and many of these showed opposite changes to the MK-801effects. Therefore, these proteins and the associated energy metabolism pathways should be explored as potential biomarkers of antipsychotic efficacy. In conclusion, MK-801 treatment of oligodendrocytes may provide a useful model for testing the efficacy of novel treatment approaches.
Markoullis, Kyriaki; Sargiannidou, Irene; Schiza, Natasa; Roncaroli, Federico; Reynolds, Richard; Kleopa, Kleopas A
Gap junctions are essential for glial cell function and have been increasingly implicated in multiple sclerosis (MS). Because increasing cortical abnormalities correlate with disease progression and cognitive dysfunction, we examined the expression of oligodendrocytic connexin32 (Cx32) and Cx47 and their astrocytic partners Cx30 and Cx43 in cortical lesions and normal-appearing gray matter (NAGM) in MS patients. Postmortem brain tissue samples from 9 MS cases were compared with 10 controls using real-time polymerase chain reaction, immunoblot, and immunohistochemical analyses. Connexin32 and Cx47 gap junction formation in oligodendrocytes was reduced within lesions, whereas Cx32 loss also extended to NAGM. In contrast, astrocytic Cx30 expression was increased within cortical lesions, whereas Cx43 was elevated in both lesions and NAGM. Diffuse microglial activation and marked astrogliotic changes accompanied these connexin abnormalities. Increased expression of Cx43 correlated with inflammatory load (r = 0.828, p = 0.042), whereas Cx32 expression correlated with longer disease duration and, therefore, milder course (r = 0.825, p = 0.043). Thus, there is a loss of intramyelin and intercellular oligodendrocyte gap junctions in MS gray matter lesions and NAGM, whereas interastrocytic gap junctions are increased, reflecting astrogliosis. These changes correlate with inflammation and disease duration and suggest that disconnection of oligodendrocytes from reactive astrocytes may play a role in failed remyelination and disease progression.
Full Text Available Krabbe disease (KD patients accumulate psychosine (galactosylsphingosine, a cytotoxic metabolite for oligodendrocytes, inducing early demyelination. Apoptosis has been suggested that plays an important role in psychosine-induced oligodendrocytes cell death in culture and in brains of Krabbe patients and an animal model of the disease (twitcher mouse. However, the molecular mechanism that triggers the activation of the apoptotic pathway, and hence the development/progression of the disease, still is not well understood. Here we report that silencing GALC gene expression induces cell death of the human derived oligodendrocyte cell line MO3.13. The induction of cell death is associated with the activation of caspase 3 and increase in Bax expression, suggesting that mitochondria is compromise, and decrease in cell survival signaling pathways such as PI3K/AKT, MAPK/ERK and AMPK, as observed by western blot analysis, 2 days after silencing. The data suggests an important psychosine-induced deregulation in apoptotic and anti-apoptotic cellular pathways. Moreover, pre-treatment with insuline-like growth factor (IGF-1 and PPARalfa agonist (WY 14643, significantly provides protection against the psychosine-induced changes described. Our data indicates that oligodendrocytes have a marked susceptibility to endogenous accumulation of psychosine and identified potential compounds that may offer protection against psychosine-induced apoptosis in vivo.
Nadjafi, S; Ebrahimi, S-A; Rahbar-Roshandel, N
This study was carried out to evaluate the effects of noscapine, a benzylisoquinoline alkaloid from opium poppy, on oligodendrocyte during ischemia/reperfusion-induced excitotoxic injury. Changes in intracellular calcium levels due to chemical ischemia and nitric oxide (NO) production during ischemia/reperfusion were evaluated as the hallmarks of ischemia-derived excitotoxic event. OLN-93 cell line (a permanent immature rat oligodendrocyte) was used as a model of oligodendrocyte. 30- or 60-minute-oxygen-glucose deprivation/24 hours reperfusion were used to induce excitotoxicity. MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) assay was used to evaluate cell viability. Ratiometric fluorescence microscopy using Ca(2+)-sensitive indicator Fura-2/AM was utilized to assess intracellular calcium levels. NO production was evaluated by Griess method. Noscapine (4 μM) significantly attenuated intracellular Ca(2+) elevation (P noscapine significantly decreased NO production during a 30-minute oxygen-glucose deprivation/reperfusion (P noscapine (4 μM) on intracellular Ca(2+) was greater than ionotropic glutamate receptors antagonists. Noscapine is protective against ischemia/reperfusion-induced excitotoxic injury in OLN-93 oligodendrocyte. This protective effect seems to be related to attenuation of intracellular Ca(2+) overload and NO production.
deVries, H; deJonge, JC; Schrage, C; vanderHaar, ME; Hoekstra, D
In oligodendrocytes (OLG), the mRNAs for the various myelin proteins localize to different intracellular sites, Whereas the confinement of myelin basic protein (MBP) mRNA to the processes of the cell has been well established, we demonstrate that most other myelin mRNA species are mainly present in
Koper, J.W.; Lopes-Cardozo, M.; Romijn, H.J.; Golde, L.M.G. van
Oligodendrocytes were isolated from the cerebra of young rats (5-10 days old) by trypsinization of the tissue followed by cell separation on Percoll gradients. The isolation was carried out in physiological, isotonic media. The cell yield was 2-4 × 10⁶ cells per brain; the plating efficiency was ≥70
Xiao, Junhua; Wong, Agnes W; Willingham, Melanie M; van den Buuse, Maarten; Kilpatrick, Trevor J; Murray, Simon S
The extracellular factors that are responsible for inducing myelination in the central nervous system (CNS) remain elusive. We investigated whether brain-derived neurotrophic factor (BDNF) is implicated, by first confirming that BDNF heterozygous mice exhibit delayed CNS myelination during early postnatal development. We next established that the influence of BDNF upon myelination was direct, by acting on oligodendrocytes, using co-cultures of dorsal root ganglia neurons and oligodendrocyte precursor cells. Importantly, we found that BDNF retains its capacity to enhance myelination of neurons or by oligodendrocytes derived from p75NTR knockout mice, indicating the expression of p75NTR is not necessary for BDNF-induced myelination. Conversely, we observed that phosphorylation of TrkB correlated with myelination, and that inhibiting TrkB signalling also inhibited the promyelinating effect of BDNF, suggesting that BDNF enhances CNS myelination via activating oligodendroglial TrkB-FL receptors. Together, our data reveal a previously unknown role for BDNF in potentiating the normal development of CNS myelination, via signalling within oligodendrocytes.
Issa P Bagayogo
Full Text Available A number of studies suggest that OLGs (oligodendrocytes), the myelinating cells of the central nervous system, are also a source of trophic molecules, such as neurotrophins that may influence survival of proximate neurons. What is less clear is how the release of these molecules may be regulated. The present study investigated the effects of BDNF (brain-derived neurotrophic factor) derived from cortical OLGs on proximate neurons, as well as regulatory mechanisms mediating BDNF release. Initial work determined that BDNF derived from cortical OLGs increased the numbers of VGLUT1 (vesicular glutamate transporter 1)-positive glutamatergic cortical neurons. Furthermore, glutamate acting through metabotropic, and not AMPA/kainate or NMDA (N-methyl-d-aspartate), receptors increased BDNF release. The PLC (phospholipase C) pathway is a key mediator of metabotropic actions to release BDNF in astrocytes and neurons. Treatment of OLGs with the PLC activator m-3M3FBS [N-(3-trifluoromethylphenyl)-2,4,6-trimethylbenzenesulfonamide] induced robust release of BDNF. Moreover, release elicited by the metabotropic receptor agonist ACPD [trans-(1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid] was inhibited by the PLC antagonist U73122, the IP3 (inositol triphosphate 3) receptor inhibitor 2-APB (2-aminoethoxydiphenylborane) and the intracellular calcium chelator BAPTA/AM [1,2-bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetra-acetic acid tetrakis(acetoxymethyl ester)]. Taken together, these results suggest that OLG lineage cells release BDNF, a molecule trophic for proximate neurons. BDNF release is regulated by glutamate acting through mGluRs (metabotropic glutamate receptors) and the PLC pathway. Thus glutamate and BDNF may be molecules that support neuron–OLG interactions in the cortex.
Autogenous arteriovenous fistulas are the preferred vascular access in patients undergoing hemodialysis. Increasing fistula prevalence depends on increasing fistula placement, improving the maturation of fistula that fail to mature and enhancing the long-term patency of mature fistula. Percutaneous methods for optimizing arteriovenous fistula maturation will be reviewed.
Barres, B A; Chun, L L; Corey, D P
White matter is a compact structure consisting primarily of neuronal axons and glial cells. As in other parts of the nervous system, the function of glial cells in white matter is poorly understood. We have explored the electrophysiological properties of two types of glial cells found predominantly in white matter: type 2 astrocytes and oligodendrocytes. Whole-cells and single-channel patch-clamp techniques were used to study these cell types in postnatal rat optic nerve cultures prepared according to the procedures of Raff et al. (Nature, 303:390-396, 1983b). Type 2 astrocytes in culture exhibit a "neuronal" channel phenotype, expressing at least six distinct ion channel types. With whole-cell recording we observed three inward currents: a voltage-sensitive sodium current qualitatively similar to that found in neurons and both transient and sustained calcium currents. In addition, type 2 astrocytes had two components of outward current: a delayed potassium current which activated at 0 mV and an inactivating calcium-dependent potassium current which activated at -30 mV. Type 2 astrocytes in culture could be induced to fire single regenerative potentials in response to injections of depolarizing current. Single-channel recording demonstrated the presence of an outwardly rectifying chloride channel in both type 2 astrocytes and oligodendrocytes, but this channel could only be observed in excised patches. Oligodendrocytes expressed only one other current: an inwardly rectifying potassium current that is mediated by 30- and 120-pS channels. Because these channels preferentially conduct potassium from outside to inside the cell, and because they are open at the resting potential of the cell, they would be appropriate for removing potassium from the extracellular space; thus it is proposed that oligodendrocytes, besides myelinating axons, play an important role in potassium regulation in white matter. The conductances present in oligodendrocytes suggest a "modulated
Full Text Available Pío del Río Hortega (1882-1945 discovered microglia and oligodendrocytes and was after Ramón y Cajal, the most prominent figure of the Spanish school of neurology. He began his scientific career with Nicolás Achúcarro with whom he learned the use of metallic impregnation techniques suitable to study non neuronal cells. Later on, he joined Cajal´s laboratory, and afterwards he created his own group where he continued developing other innovative modifications of the silver staining methods that revolutionised the study of glial cells a century ago. He was at that time also interested in neuropathology and became a leading authority in Central Nervous System (CNS tumours. In parallel to this clinical activity, del Río Hortega rendered the first systematic description of the great polymorphism present in a subtype of macroglial cells that he named himself as oligodendroglia and later oligodendrocytes. He established their ectodermic origin and suggested that they build the myelin sheath of CNS axons, just as Schwann cells do in the periphery. Notably, he also suggested the trophic role of oligodendrocytes for neuronal functionality, an idea that it has been substantiated in the last few years. Del Río Hortega became internationally recognized and established an important neurohistological school with outstanding pupils from Spain and abroad, which nearly disappeared after his exile due to the Spanish civil war. Yet, the difficulty of metal impregnation methods and their variability in results, delayed for some decades the confirmation of his great insights into oligodendrocyte biology until the development of electron microscopy and immunohistochemistry. This review aims at summarizing the pioneer and essential contributions of del Río Hortega to the current knowledge of oligodendrocyte structure and function, and to provide a hint of the scientific personality of this extraordinary and insufficiently recognized man.
Michele D Binder
Full Text Available Multiple sclerosis (MS is a complex demyelinating disease of the central nervous system. Current research has shown that at least in some cases, the primary insult in MS could be directed at the oligodendrocyte, and that the earliest immune responses are primarily via innate immune cells. We have identified a family of receptor protein tyrosine kinases, known as the TAM receptors (Tyro3, Axl and Mertk, as potentially important in regulating both the oligodendrocyte and immune responses. We have previously shown that Gas6, a ligand for the TAM receptors, can affect the severity of demyelination in mice, with a loss of signalling via Gas6 leading to decreased oligodendrocyte survival and increased microglial activation during cuprizone-induced demyelination. We hypothesised TAM receptor signalling would also influence the extent of recovery in mice following demyelination. A significant effect of the absence of Gas6 was detected upon remyelination, with a lower level of myelination after 4 weeks of recovery in comparison with wild-type mice. The delay in remyelination was accompanied by a reduction in oligodendrocyte numbers. To understand the molecular mechanisms that drive the observed effects, we also examined the effect of exogenous Gas6 in in vitro myelination assays. We found that Gas6 significantly increased myelination in a dose-dependent manner, suggesting that TAM receptor signalling could be directly involved in myelination by oligodendrocytes. The reduced rate of remyelination in the absence of Gas6 could thus result from a lack of Gas6 at a critical time during myelin production after injury. These findings establish Gas6 as an important regulator of both CNS demyelination and remyelination.
Domercq, Maria; Mato, Susana; Soria, Federico N; Sánchez-gómez, M Victoria; Alberdi, Elena; Matute, Carlos
Much of the cell death following episodes of anoxia and ischemia in the mammalian central nervous system has been attributed to extracellular accumulation of glutamate and ATP, which causes a rise in [Ca(2+)](i), loss of mitochondrial potential, and cell death. However, restoration of blood flow and reoxygenation are frequently associated with exacerbation of tissue injury (the oxygen paradox). Herein we describe a novel signaling pathway that is activated during ischemia-like conditions (oxygen and glucose deprivation; OGD) and contributes to ischemia-induced oligodendroglial cell death. OGD induced a retarded and sustained increase in extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation after restoring glucose and O(2) (reperfusion-like conditions). Blocking the ERK1/2 pathway with the MEK inhibitor UO126 largely protected oligodendrocytes against ischemic insults. ERK1/2 activation was blocked by the high-affinity Zn(2+) chelator TPEN, but not by antagonists of AMPA/kainate or P2X7 receptors that were previously shown to be involved in ischemic oligodendroglial cell death. Using a high-affinity Zn(2+) probe, we showed that ischemia induced an intracellular Zn(2+) rise in oligodendrocytes, and that incubation with TPEN prevented mitochondrial depolarization and ROS generation after ischemia. Accordingly, exposure to TPEN and the antioxidant Trolox reduced ischemia-induced oligodendrocyte death. Moreover, UO126 blocked the ischemia-induced increase in poly-[ADP]-ribosylation of proteins, and the poly[ADP]-ribose polymerase 1 (PARP-1) inhibitor DPQ significantly inhibited ischemia-induced oligodendroglial cell death-demonstrating that PARP-1 was required downstream in the Zn(2+)-ERK oligodendrocyte cell death pathway. Chelation of cytosolic Zn(2+), blocking ERK signaling, and antioxidants may be beneficial for treating CNS white matter ischemia-reperfusion injury. Importantly, all the inhibitors of this pathway protected oligodendrocytes when applied
Full Text Available Abstract Background Myelination requires precise control of oligodendrocyte morphology and myelin generation at each of the axons contacted by an individual cell. This control must involve the integration of extracellular cues, such as those on the axon surface, with intrinsic developmental programmes. We asked whether integrins represent one class of oligodendrocyte cell-surface receptors able to provide this integration. Results Integrins signal via a process of activation, a conformational change that can be induced either by "outside-in" signals comprising physiological extracellular matrix ligands (mimicked by the pharmacological use of the divalent cation manganese or "inside-out" signalling molecules such as R-Ras. Increasing levels of outside-in signalling via the laminin receptor α6β1 integrin were found to promote oligodendrocyte processing and myelin sheet formation in culture. Similar results were obtained when inside-out signalling was increased by the expression of a constitutively-active R-Ras. Inhibiting inside-out signalling by using dominant-negative R-Ras reduces processes and myelin sheets; importantly, this can be partially rescued by the co-stimulation of outside-in signalling using manganese. Conclusion The balance of the equilibrium between active and inactive integrins regulates oligodendrocyte morphology, which is itself regulated by extrinsic and intrinsic cues so providing a mechanism of signal integration. As laminins capable of providing outside-in signals are present on axons at the time of myelination, a mechanism exists by which morphology and myelin generation might be regulated independently in each oligodendrocyte process.
Asi, Yasmine T; Simpson, Julie E; Heath, Paul R; Wharton, Stephen B; Lees, Andrew J; Revesz, Tamas; Houlden, Henry; Holton, Janice L
Multiple system atrophy (MSA) is a progressive neurodegenerative disease presenting clinically with parkinsonian, cerebellar, and autonomic features. α-Synuclein (αsyn), encoded by the gene SNCA, is the main constituent of glial cytoplasmic inclusion (GCI) found in oligodendrocytes in MSA, but the methods of its accumulation have not been established. The aim of this study is to investigate alterations in regional and cellular SNCA mRNA expression in MSA as a possible substrate for GCI formation. Quantitative reverse transcription polymerase chain reaction (qPCR) was performed on postmortem brain samples from 15 MSA, 5 IPD, and 5 control cases to investigate regional expression in the frontal and occipital regions, dorsal putamen, pontine base, and cerebellum. For cellular expression analysis, neurons and oligodendrocytes were isolated by laser-capture microdissection from five MSA and five control cases. SNCA mRNA expression was not significantly different between the MSA, IPD and control cases in all regions (multilevel model, P = 0.14). After adjusting for group effect, the highest expression was found in the occipital cortex while the lowest was in the putamen (multilevel model, P MSA oligodendrocytes expressed more SNCA than control oligodendrocytes and expression in MSA neurons was slightly lower than that in controls, however, these results did not reach statistical significance. We have demonstrated regional variations in SNCA expression, which is higher in cortical than subcortical regions. This study is the first to demonstrate SNCA mRNA expression by oligodendrocytes in human postmortem tissue using qPCR and, although not statistically significant, could suggest that this may be increased in MSA compared to controls.
G.W. Henkel; S.R. McKercher; P.J. Leenen (Pieter); R.A. Maki
textabstractMice homozygous for the disruption of the PU.1 (Spi-1) gene do not produce mature macrophages. In determining the role of PU.1 in macrophage differentiation, the present study investigated whether or not there was commitment to the monocytic lineage in the a
Conclusions: We concluded that berberine protected OLN-93 oligodendrocyte against ischemic induced excitotoxic injury. Attenuation of intracellular Ca 2+ overload by berberine may be the key mechanism that saved OLN-93 from excitotoxicity damage.
Thiruvalluvan, Arun; Czepiel, Marcin; Kap, Yolanda A; Mantingh-Otter, Ietje; Vainchtein, Ilia; Kuipers, Jeroen; Bijlard, Marjolein; Baron, Wia; Giepmans, Ben; Brück, Wolfgang; 't Hart, Bert A; Boddeke, Erik; Copray, Sjef
: Fast remyelination by endogenous oligodendrocyte precursor cells (OPCs) is essential to prevent axonal and subsequent retrograde neuronal degeneration in demyelinating lesions in multiple sclerosis (MS). In chronic lesions, however, the remyelination capacity of OPCs becomes insufficient. Cell the
Saxena, Amit; Bauer, Jan; Scheikl, Tanja; Zappulla, Jacques; Audebert, Marc; Desbois, Sabine; Waisman, Ari; Lassmann, Hans; Liblau, Roland S; Mars, Lennart T
CD8 T cells are emerging as important players in multiple sclerosis (MS) pathogenesis, although their direct contribution to tissue damage is still debated. To assess whether autoreactive CD8 T cells can contribute to the pronounced loss of oligodendrocytes observed in MS plaques, we generated mice in which the model Ag influenza hemagglutinin is selectively expressed in oligodendrocytes. Transfer of preactivated hemagglutinin-specific CD8 T cells led to inflammatory lesions in the optic nerve, spinal cord, and brain. These lesions, associating CD8 T cell infiltration with focal loss of oligodendrocytes, demyelination, and microglia activation, were very reminiscent of active MS lesions. Thus, our study demonstrates the potential of CD8 T cells to induce oligodendrocyte lysis in vivo as a likely consequence of direct Ag-recognition. These results provide new insights with regard to CNS tissue damage mediated by CD8 T cells and for understanding the role of CD8 T cells in MS.
Full Text Available In recent years there has been an increasing interest in maturity models in management-related disciplines; which reflects a growing recognition that becoming more mature and having a model to guide the route to maturity can help organisations in managing major transformational change. Lean Construction (LC is an increasingly important improvement approach that organisations seek to embed. This study explores how to apply the maturity models to LC. Hence the attitudes, opinions and experiences of key industry informants with high levels of knowledge of LC were investigated. To achieve this, a review of maturity models was conducted, and data for the analysis was collected through a sequential process involving three methods. First a group interview with seven key informants. Second a follow up discussion with the same individuals to investigate some of the issues raised in more depth. Third an online discussion held via LinkedIn in which members shared their views on some of the results. Overall, we found that there is a lack of common understanding as to what maturity means in LC, though there is general agreement that the concept of maturity is a suitable one to reflect the path of evolution for LC within organisations.
Full Text Available In recent years there has been an increasing interest in maturity models in management-related disciplines; which reflects a growing recognition that becoming more mature and having a model to guide the route to maturity can help organisations in managing major transformational change. Lean Construction (LC is an increasingly important improvement approach that organisations seek to embed. This study explores how to apply the maturity models to LC. Hence the attitudes, opinions and experiences of key industry informants with high levels of knowledge of LC were investigated. To achieve this, a review of maturity models was conducted, and data for the analysis was collected through a sequential process involving three methods. First a group interview with seven key informants. Second a follow up discussion with the same individuals to investigate some of the issues raised in more depth. Third an online discussion held via LinkedIn in which members shared their views on some of the results. Overall, we found that there is a lack of common understanding as to what maturity means in LC, though there is general agreement that the concept of maturity is a suitable one to reflect the path of evolution for LC within organisations.
Rajani, Rikesh M.
Cerebral small vessel disease (SVD) is a prevalent, neurological disease that significantly increases the risk of stroke and dementia. The main pathological changes are vascular, in the form of lipohyalinosis and arteriosclerosis, and in the white matter (WM), in the form of WM lesions. Despite this, it is unclear to what extent the key cell types involved–the endothelial cells (ECs) of the vasculature and the oligodendrocytes of the WM–interact. Here, we describe the work that has so far been carried out suggesting an interaction between ECs and oligodendrocytes in SVD. As these interactions have been studied in more detail in other disease states and in development, we explore these systems and discuss the role these mechanisms may play in SVD. PMID:28202749
Jepson, Scott; Vought, Bryan; Gross, Christian H; Gan, Lu; Austen, Douglas; Frantz, J Daniel; Zwahlen, Jacque; Lowe, Derek; Markland, William; Krauss, Raul
Overcoming remyelination failure is a major goal of new therapies for demyelinating diseases like multiple sclerosis. LINGO-1, a key negative regulator of myelination, is a transmembrane signaling protein expressed in both neurons and oligodendrocytes. In neurons, LINGO-1 is an integral component of the Nogo receptor complex, which inhibits axonal growth via RhoA. Because the only ligand-binding subunit of this complex, the Nogo receptor, is absent in oligodendrocytes, the extracellular signals that inhibit myelination through a LINGO-1-mediated mechanism are unknown. Here we show that LINGO-1 inhibits oligodendrocyte terminal differentiation through intercellular interactions and is capable of a self-association in trans. Consistent with previous reports, overexpression of full-length LINGO-1 inhibited differentiation of oligodendrocyte precursor cells (OPCs). Unexpectedly, treatment with a soluble recombinant LINGO-1 ectodomain also had an inhibitory effect on OPCs and decreased myelinated axonal segments in cocultures with neurons from dorsal root ganglia. We demonstrated LINGO-1-mediated inhibition of OPCs through intercellular signaling by using a surface-bound LINGO-1 construct expressed ectopically in astrocytes. Further investigation showed that the soluble LINGO-1 ectodomain can interact with itself in trans by binding to CHO cells expressing full-length LINGO-1. Finally, we observed that soluble LINGO-1 could activate RhoA in OPCs. We propose that LINGO-1 acts as both a ligand and a receptor and that the mechanism by which it negatively regulates OPC differentiation and myelination is mediated by a homophilic intercellular interaction. Disruption of this protein-protein interaction could lead to a decrease of LINGO-1 inhibition and an increase in myelination.
Full Text Available Autoregulation of transcription factors and cross-antagonism between lineage-specific transcription factors are a recurrent theme in cell differentiation. An equally prevalent event that is frequently overlooked in lineage commitment models is the upregulation of lineage-specific receptors, often through lineage-specific transcription factors. Here, we use a minimal model that combines cell-extrinsic and cell-intrinsic elements of regulation in order to understand how both instructive and stochastic events can inform cell commitment decisions in hematopoiesis. Our results suggest that cytokine-mediated positive receptor feedback can induce a "switch-like" response to external stimuli during multilineage differentiation by providing robustness to both bipotent and committed states while protecting progenitors from noise-induced differentiation or decommitment. Our model provides support to both the instructive and stochastic theories of commitment: cell fates are ultimately driven by lineage-specific transcription factors, but cytokine signaling can strongly bias lineage commitment by regulating these inherently noisy cell-fate decisions with complex, pertinent behaviors such as ligand-mediated ultrasensitivity and robust multistability. The simulations further suggest that the kinetics of differentiation to a mature cell state can depend on the starting progenitor state as well as on the route of commitment that is chosen. Lastly, our model shows good agreement with lineage-specific receptor expression kinetics from microarray experiments and provides a computational framework that can integrate both classical and alternative commitment paths in hematopoiesis that have been observed experimentally.
Lee, Xinhua; Yang, Zhongshu; Shao, Zhaohui; Rosenberg, Sheila S; Levesque, Melissa; Pepinsky, R Blake; Qiu, Mengsheng; Miller, Robert H; Chan, Jonah R; Mi, Sha
Neurons and glia share a mutual dependence in establishing a functional relationship, and none is more evident than the process by which axons control myelination. Here, we identify LRR and Ig domain-containing, Nogo receptor-interacting protein (LINGO-1) as a potent axonal inhibitor of oligodendrocyte differentiation and myelination that is regulated by nerve growth factor and its cognate receptor TrkA in a dose-dependent manner. Whereas LINGO-1 expressed by oligodendrocyte progenitor cells was previously identified as an inhibitor of differentiation, we demonstrate that axonal expression of LINGO-1 inhibits differentiation with equal potency. Disruption of LINGO-1 on either cell type is sufficient to overcome the inhibitory action and promote differentiation and myelination, independent of axon diameter. Furthermore, these results were recapitulated in transgenic mice overexpressing the full length LINGO-1 under the neuronal promoter synapsin. Myelination was greatly inhibited in the presence of enforced axonal LINGO-1. The implications of these results relate specifically to the development of potential therapeutics targeting extrinsic growth factors that may regulate the axonal expression of modulators of oligodendrocyte development.
Olsen, John A; Kenna, Lauren A; Tipon, Regine C; Spelios, Michael G; Stecker, Mark M; Akirav, Eitan M
Multiple sclerosis (MS) is a neurodegenerative disease of the central nervous system (CNS). Minimally invasive biomarkers of MS are required for disease diagnosis and treatment. Differentially methylated circulating-free DNA (cfDNA) is a useful biomarker for disease diagnosis and prognosis, and may offer to be a viable approach for understanding MS. Here, methylation-specific primers and quantitative real-time PCR were used to study methylation patterns of the myelin oligodendrocyte glycoprotein (MOG) gene, which is expressed primarily in myelin-producing oligodendrocytes (ODCs). MOG-DNA was demethylated in O4(+) ODCs in mice and in DNA from human oligodendrocyte precursor cells (OPCs) when compared with other cell types. In the cuprizone-fed mouse model of demyelination, ODC derived demethylated MOG cfDNA was increased in serum and was associated with tissue-wide demyelination, demonstrating the utility of demethylated MOG cfDNA as a biomarker of ODC death. Collected sera from patients with active (symptomatic) relapsing-remitting MS (RRMS) demonstrated a higher signature of demethylated MOG cfDNA when compared with patients with inactive disease and healthy controls. Taken together, these results offer a minimally invasive approach to measuring ODC death in the blood of MS patients that may be used to monitor disease progression.
Cervellini, Ilaria; Annenkov, Alexander; Brenton, Thomas; Chernajovsky, Yuti; Ghezzi, Pietro; Mengozzi, Manuela
Erythropoietin (EPO) has protective effects in neurodegenerative and neuroinflammatory diseases, including in animal models of multiple sclerosis, where EPO decreases disease severity. EPO also promotes neurogenesis and is protective in models of toxic demyelination. In this study, we asked whether EPO could promote neurorepair by also inducing remyelination. In addition, we investigated whether the effect of EPO could be mediated by the classical erythropoietic EPO receptor (EPOR), since it is still questioned if EPOR is functional in nonhematopoietic cells. Using CG4 cells, a line of rat oligodendrocyte precursor cells, we found that EPO increases the expression of myelin genes (myelin oligodendrocyte glycoprotein [MOG] and myelin basic protein [MBP]). EPO had no effect in wild-type CG4 cells, which do not express EPOR, whereas it increased MOG and MBP expression in cells engineered to overexpress EPOR (CG4-EPOR). This was reflected in a marked increase in MOG protein levels, as detected by Western blot. In these cells, EPO induced by 10-fold the early growth response gene 2 (Egr2), which is required for peripheral myelination. However, Egr2 silencing with a siRNA did not reverse the effect of EPO, indicating that EPO acts through other pathways. In conclusion, EPO induces the expression of myelin genes in oligodendrocytes and this effect requires the presence of EPOR. This study demonstrates that EPOR can mediate neuroreparative effects.
Liu, Xiujie; Lu, Yan; Zhang, Yong; Li, Yuanyuan; Zhou, Jiazhen; Yuan, Yimin; Gao, Xiaofei; Su, Zhida; He, Cheng
Oligodendrocyte precursor cells (OPCs) are a unique type of glia that are responsible for the myelination of the central nervous system. OPC migration is important for myelin formation during central nervous system development and repair. However, the precise extracellular and intracellular mechanisms that regulate OPC migration remain elusive. Slits were reported to regulate neurodevelopmental processes such as migration, adhesion, axon guidance, and elongation through binding to roundabout receptors (Robos). However, the potential roles of Slits/Robos in oligodendrocytes remain unknown. In this study, Slit2 was found to be involved in regulating the dispersal of OPCs through the association between Robo1 and Fyn. Initially, we examined the expression of Robos in OPCs both in vitro and in vivo. Subsequently, the Boyden chamber assay showed that Slit2 could inhibit OPC migration. RoboN, a specific inhibitor of Robos, could significantly attenuate this effect. The effects were confirmed through the explant migration assay. Furthermore, treating OPCs with Slit2 protein deactivated Fyn and increased the level of activated RhoA-GTP. Finally, Fyn was found to form complexes with Robo1, but this association was decreased after Slit2 stimulation. Thus, we demonstrate for the first time that Slit2 regulates the dispersal of oligodendrocyte precursor cells through Fyn and RhoA signaling.
Full Text Available Multipotent cells from the juvenile subventricular zone (SVZ possess the ability to differentiate into new neural cells. Depending on local signals, SVZ can generate new neurons, astrocytes or oligodendrocytes. We previously demonstrated that activation of NMDA receptors in SVZ progenitors increases the rate of oligodendrocyte differentiation. Here we investigated the mechanisms involved in NMDA receptor-dependent differentiation. Using functional studies performed with the reporter gene luciferase we found that activation of NMDA receptor stimulates PKC. In turn, stimulation of PKC precedes the activation of NADPH oxidase (NOX as demonstrated by translocation of the p67phox subunit to the cellular membrane. We propose that NOX2 is involved in the transduction of the signal from NMDA receptors through PKC activation as the inhibitor gp91 reduced their pro-differentiation effect. In addition, our data and that from other groups suggest that signaling through the NMDA receptor/PKC/NOX2 cascade generates ROS that activate the PI3/mTOR pathway and finally leads to the generation of new oligodendrocytes.
Full Text Available In contrast to mature cardiomyocytes which have limited regenerative capacity, pluripotent stem cells represent a promising source for the generation of new cardiomyocytes. The tendency of pluripotent stem cells to form teratomas and the heterogeneity from various differentiation stages and cardiomyocyte cell sub-types, however, are major obstacles to overcome before this type of therapy could be applied in a clinical setting. Thus, the identification of extracellular markers for specific cardiomyocyte progenitors and mature subpopulations is of particular importance. The delineation of cardiomyocyte surface marker patterns not only serves as a means to derive homogeneous cell populations by FACS, but is also an essential tool to understand cardiac development. By using single-cell expression profiling in early mouse embryonic hearts, we found that a combination of integrin alpha-1, alpha-5, alpha-6 and N-cadherin enables isolation of lineage committed murine cardiomyocytes. Additionally, we were able to separate trabecular cardiomyocytes from solid ventricular myocardium and atrial murine cells. These cells exhibit expected subtype specific phenotype confirmed by electrophysiological analysis. We show that integrin expression can be used for the isolation of living, functional and lineage-specific murine cardiomyocytes.
Treutlein, Barbara; Brownfield, Doug G; Wu, Angela R; Neff, Norma F; Mantalas, Gary L; Espinoza, F Hernan; Desai, Tushar J; Krasnow, Mark A; Quake, Stephen R
The mammalian lung is a highly branched network in which the distal regions of the bronchial tree transform during development into a densely packed honeycomb of alveolar air sacs that mediate gas exchange. Although this transformation has been studied by marker expression analysis and fate-mapping, the mechanisms that control the progression of lung progenitors along distinct lineages into mature alveolar cell types are still incompletely known, in part because of the limited number of lineage markers and the effects of ensemble averaging in conventional transcriptome analysis experiments on cell populations. Here we show that single-cell transcriptome analysis circumvents these problems and enables direct measurement of the various cell types and hierarchies in the developing lung. We used microfluidic single-cell RNA sequencing (RNA-seq) on 198 individual cells at four different stages encompassing alveolar differentiation to measure the transcriptional states which define the developmental and cellular hierarchy of the distal mouse lung epithelium. We empirically classified cells into distinct groups by using an unbiased genome-wide approach that did not require a priori knowledge of the underlying cell types or the previous purification of cell populations. The results confirmed the basic outlines of the classical model of epithelial cell-type diversity in the distal lung and led to the discovery of many previously unknown cell-type markers, including transcriptional regulators that discriminate between the different populations. We reconstructed the molecular steps during maturation of bipotential progenitors along both alveolar lineages and elucidated the full life cycle of the alveolar type 2 cell lineage. This single-cell genomics approach is applicable to any developing or mature tissue to robustly delineate molecularly distinct cell types, define progenitors and lineage hierarchies, and identify lineage-specific regulatory factors.
Full Text Available Today it is crucial for organizations to pay even greater attention on quality management as the importance of this function in achieving ultimate business objectives is increasingly becoming clearer. Importance of the Quality Management (QM Function in achieving basic need by ensuring compliance with Capability Maturity Model Integrated (CMMI / International Organization for Standardization (ISO is a basic demand from business nowadays. However, QM Function and its processes need to be made much more mature to prevent delivery outages and to achieve business excellence through their review and auditing capability. Many organizations now face challenges in determining the maturity of the QM group along with the service offered by them and the right way to elevate the maturity of the same. The objective of this whitepaper is to propose a new model –the Audit Maturity Model (AMM which will provide organizations with a measure of their maturity in quality management in the perspective of auditing, along with recommendations for preventing delivery outage, and identifying risk to achieve business excellence. This will enable organizations to assess QM maturity higher than basic hygiene and will also help them to identify gaps and to take corrective actions for achieving higher maturity levels. Hence the objective is to envisage a new auditing model as a part of organisation quality management function which can be a guide for them to achieve higher level of maturity and ultimately help to achieve delivery and business excellence.
Lijun Yang; Hong Cui; Aijun Yang; Wenxing Jiang
To examine the expression profiles of oligodendrocyte transcription factors 1 and 2 (Olig1 and Olig2) and the interaction between these two proteins, Olig1 was transfected into the lateral ventricles of neonatal rats subjected to hypoxia. Immunohistochemistry demonstrated that Olig2 was expressed throughout the nuclei in the brain, and expression increased at 3 days following hypoxia and was higher than levels at 7 days following Ad5-Olig1 transfection. Western blot revealed that Olig1 and Olig2 expression increased in Olig1-transfected brain cells 3 days after hypoxia, but Olig1 and Olig2 expression decreased at 7 days. These results indicate that Olig1 overexpression enhances Olig2 expression in brain tissues of hypoxia rats.
Chung, Ah-Young; Kim, Suhyun; Kim, Eunmi; Kim, Dohyun; Jeong, Inyoung; Cha, Young Ryun; Bae, Young-ki; Park, Seung Woo; Lee, Jehee; Park, Hae-Chul
A subset of ventral spinal cord precursors, known as pMN precursor cells, initially generate motor neurons and then oligodendrocyte progenitor cells (OPCs), which migrate and differentiate as myelinating oligodendrocytes in the developing neural tube. The switch between motor neuron and oligodendrocyte production by the pMN neural precursors is an important step in building a functional nervous system. However, the precise mechanism that orchestrates the sequential generation of motor neurons and oligodendrocytes within the common population of pMN precursors is still unclear. The current study demonstrates that Indian Hedgehog b (Ihhb), previously known as Echidna Hedgehog, begins to be expressed in the floor plate cells of the ventral spinal cord at the time of OPC specification in zebrafish embryos. Ihhb loss-of-function analysis revealed that Ihhb function is required for OPC specification from pMN precursors by negatively regulating the proliferation of neural precursors. Finally, results showed that Sonic Hedgehog (Shh) could not replace Ihhb function in OPC specification, suggesting that Ihhb and Shh play separate roles in OPC specification. Altogether, data from the present study suggested a novel mechanism, mediated by Ihhb, for the sequential generation of motor neurons and oligodendrocytes from pMN precursors in the ventral spinal cord of zebrafish embryos.
Raju, Ravali; Chau, David; Cho, Dong Seong; Park, Yonsil; Verfaillie, Catherine M; Hu, Wei-Shou
The differentiation of human pluripotent stem cells toward the hepatocyte lineage can potentially provide an unlimited source of functional hepatocytes for transplantation and extracorporeal bioartificial liver applications. It is anticipated that the quantities of cells needed for these applications will be in the order of 10(9)-10(10) cells, because of the size of the liver. An ideal differentiation protocol would be to enable directed differentiation to the hepatocyte lineage with simultaneous cell expansion. We introduced a cell expansion stage after the commitment of human embryonic stem cells to the endodermal lineage, to allow for at least an eightfold increase in cell number, with continuation of cell maturation toward the hepatocyte lineage. The progressive changes in the transcriptome were measured by expression array, and the expression dynamics of certain lineage markers was measured by mass cytometry during the differentiation and expansion process. The findings revealed that while cells were expanding they were also capable of progressing in their differentiation toward the hepatocyte lineage. In addition, our transcriptome, protein and functional studies, including albumin secretion, drug-induced CYP450 expression and urea production, all indicated that the hepatocyte-like cells obtained with or without cell expansion are very similar. This method of simultaneous cell expansion and hepatocyte differentiation should facilitate obtaining large quantities of cells for liver cell applications.
Pérez-Cerdá, Fernando; Sánchez-Gómez, María Victoria; Matute, Carlos
Pío del Río Hortega (1882–1945) discovered microglia and oligodendrocytes (OLGs), and after Ramón y Cajal, was the most prominent figure of the Spanish school of neurology. He began his scientific career with Nicolás Achúcarro from whom he learned the use of metallic impregnation techniques suitable to study non-neuronal cells. Later on, he joined Cajal’s laboratory. and Subsequently, he created his own group, where he continued to develop other innovative modifications of silver staining methods that revolutionized the study of glial cells a century ago. He was also interested in neuropathology and became a leading authority on Central Nervous System (CNS) tumors. In parallel to this clinical activity, del Río Hortega rendered the first systematic description of a major polymorphism present in a subtype of macroglial cells that he named as oligodendroglia and later OLGs. He established their ectodermal origin and suggested that they built the myelin sheath of CNS axons, just as Schwann cells did in the periphery. Notably, he also suggested the trophic role of OLGs for neuronal functionality, an idea that has been substantiated in the last few years. Del Río Hortega became internationally recognized and established an important neurohistological school with outstanding pupils from Spain and abroad, which nearly disappeared after his exile due to the Spanish civil war. Yet, the difficulty of metal impregnation methods and their variability in results, delayed for some decades the confirmation of his great insights into oligodendrocyte biology until the development of electron microscopy and immunohistochemistry. This review aims at summarizing the pioneer and essential contributions of del Río Hortega to the current knowledge of oligodendrocyte structure and function, and to provide a hint of the scientific personality of this extraordinary and insufficiently recognized man. PMID:26217196
Nielsen, Helle Hvilsted; Ladeby, Rune; Drøjdahl, Nina
the response of the NG2+ cells to the different components of demyelinating pathology, we investigated the response of adult NG2+ cells to axonal degeneration in the absence of primary myelin or oligodendrocyte pathology. Axonal degeneration was induced in the hippocampal dentate gyrus of adult mice...... by transection of the entorhino-dentate perforant path projection. The acutely induced degeneration of axons and terminals resulted in a prompt response of NG2+ cells, consisting of morphological transformation, cellular proliferation, and upregulation of NG2 expression days 2-3 after surgery. This was followed...
Bronstein, J.M.; Wu, S.; Korenberg, J.R. [UCLA School of Medicine, Los Angeles, CA (United States)] [and others
Oligodendrocyte-specific protein (OSP) is a recently described protein present only in myelin of the central nervous system. Several inherited disorders of myelin are caused by mutations in myelin genes but the etiology of many remain unknown. We mapped the location of the mouse OSP gene to the proximal region of chromosome 3 using two sets of multilocus crosses and to human chromosome 3 using somatic cell hybrids. Fine mapping with fluorescence in situ hybridization placed the OSP gene at human chromosome 3q26.2-q26.3. To date, there are no known inherited neurological disorders that localize to these regions. 24 refs., 2 figs.
Cai, Jun; Tuong, Chi Minh; Zhang, Yiping; Shields, Christopher B; Guo, Gang; Fu, Hui; Gozal, David
Premature babies are at high risk for both infantile apnoea and long-term neurobehavioural deficits. Recent studies suggest that diffuse structural changes in brain white matter are a positive predictor of poor cognitive outcomes. Since oligodendrocyte maturation, myelination, axon development, and synapse formation mainly occur in the third trimester of gestation and first postnatal year, infantile apnoea could lead to and/or exaggerate white matter impairments in preterm neonates. Therefore, we investigated oligodendroglia and axon development in a neonatal mouse model of intermittent hypoxia between postnatal days 2 and 10. During critical phases of central nervous system development, intermittent hypoxia induced hypomyelination in the corpus callosum, striatum, fornix, and cerebellum, but not in the pons or spinal cord. Intermittent hypoxia-elicited alterations in myelin-forming processes were reflected by decreased expression of myelin proteins, including MBP, PLP, MAG, and CNPase, possibly due to arrested maturation of oligodendrocytes. Ultrastructural abnormalities were apparent in the myelin sheath and axon. Immature oligodendrocytes were more vulnerable to neonatal intermittent hypoxia exposures than developing axons, suggesting that hypomyelination may contribute, at least partially, to axonal deficits. Insufficient neurofilament synthesis with anomalous components of neurofilament subunits, β-tubulin, and MAP2 isoforms indicated immaturity of axons in intermittent hypoxia-exposed mouse brains. In addition, down-regulation of synapsin I, synaptophysin, and Gap-43 phosphorylation suggested a potential stunt in axonogenesis and synaptogenesis. The region-selective and complex impairment in brain white matter induced by intermittent hypoxia was further associated with electrophysiological changes that may underlie long-term neurobehavioural sequelae.
Nadjafi, Shabnam; Ebrahimi, Soltan-Ahmad; Rahbar-Roshandel, Nahid
In this study, the effect of berberine, an isoquinoline alkaloid isolated from Coptidis rhizoma, on Nitric Oxide (NO) production, as a possible involved factor, during excitotoxic injury in oligodendroglial cells were evaluated. The overactivation of ionotropic glutamate receptors which is known as the excitotoxicity, is an important phenomenon because of the contribution in acute injury to the central nervous system, chronic neurodegenerative disorders, oligodendrocyte loss and demyelinating diseases as Multiple Sclerosis (MS). Intracellular Ca2+ overload, have a key role during excitotoxic injury and such increase in cytoplasmic Ca2+ triggers a series of events such as production of NO that end to cell death. Previous report showed the protective effects of berberine on ischemic-induced excitotoxic insult in oligodendrocytes. Hereby, we intended to know if the NO production could be associated with oxygen-glucose deprivation/reperfusion-induced excitotoxic damage in oligodendrocyte; moreover, the alteration of NO production could be considered as an involved mechanism for protective effect of berberine in such condition. Therefore, the effect of berberine (2 μM) on NO production during oxygen-glucose deprivation/24 h reperfusion in oligodendrocytes were examined. The OLN-93 cell line (a permanent immature rat oligodendrocyte) was used as a model of oligodendrocyte. Thirty minutes-oxygen-glucose deprivation/24 h reperfusion was used to induce excitotoxicity. NO production was evaluated by Griess method. Our results demonstrated that berberine (2 μM) significantly decreased NO production during 30 min oxygen-glucose deprivation/reperfusion. It seems that blockade of NO production by berberine may also participate in oligodendroglial cell protection against oxygen-glucose deprivation/reperfusion-induced insult.
Ruiz, A; Matute, C; Alberdi, E
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
Seiberlich, Veronika; Bauer, Nina G; Schwarz, Lisa; Ffrench-Constant, Charles; Goldbaum, Olaf; Richter-Landsberg, Christiane
Oligodendrocytes, the myelin forming cells of the CNS, are characterized by their numerous membranous extensions, which enwrap neuronal axons and form myelin sheaths. During differentiation oligodendrocytes pass different morphological stages, downregulate the expression of the proteoglycan NG2, and acquire major myelin specific proteins, such as myelin basic proteins (MBP) and proteolipid protein. MBP mRNA is transported in RNA granules along the microtubules (MTs) to the periphery and translated locally. MTs participate in the elaboration and stabilization of the myelin forming extensions and are essential for cellular sorting processes. Their dynamic properties are regulated by microtubule associated proteins (MAPs). The MAP tau is present in oligodendrocytes and involved in the regulation and stabilization of the MT network. To further elucidate the functional significance of tau in oligodendrocytes, we have downregulated tau by siRNA technology and studied the effects on cell differentiation and neuron-glia contact formation. The data show that tau knockdown impairs process outgrowth and leads to a decrease in MBP expression. Furthermore, MBP mRNA transport to distant cellular extensions is impaired and cells remain in the NG2 stage. In myelinating cocultures with dorsal root ganglion neurons, oligodendrocyte precursor cells after tau miR RNA lentiviral knockdown develop into NG2 positive cells with very long and thin processes, contacting axons loosely, but fail to form internodes. This demonstrates that tau is important for MBP mRNA transport and involved in process formation. The disturbance of the balance of tau leads to abnormalities in oligodendrocyte differentiation, neuron-glia contact formation and the early myelination process.
Wicher, Grzegorz; Larsson, Mårten; Svenningsen, Åsa Fex
Lipoprotein receptor-related protein-2 (LRP2)/megalin is a member of the low density lipoprotein receptor (LDLR) family, and is essential in absorptive epithelia for endocytosis of lipoproteins, low molecular weight proteins, cholesterol and vitamins, as well as in cellular signaling. Previous st...... that spinal cord oligodendrocytes are phenotypically different from those in the brain, and indicate that megalin translocates signals from the cell membrane to the nucleus of oligodendrocytes during the formation and maintenance of myelin of long spinal cord pathways....
Laursen, Lisbeth Schmidt; Chan, Colin W; ffrench-Constant, Charles
Myelination in the central nervous system provides a unique example of how cells establish asymmetry. The myelinating cell, the oligodendrocyte, extends processes to and wraps multiple axons of different diameter, keeping the number of wraps proportional to the axon diameter. Local regulation...... translation of a key sheath protein, myelin basic protein (MBP), by reversing the inhibitory effect of the mRNA 3′UTR. During oligodendrocyte differentiation and myelination α6β1-integrin interacts with hnRNP-K, an mRNA-binding protein, which binds to MBP mRNA and translocates from the nucleus to the myelin...
Franco, Paula G.; Pasquini, Juana M.; Silvestroff, Lucas
Neural Stem and Progenitor Cells (NSC/NPC) are gathering tangible recognition for their uses in cell therapy and cell replacement therapies for human disease, as well as a model system to continue research on overall neural developmental processes in vitro. The Subventricular Zone is one of the largest NSC/NPC niches in the developing mammalian Central Nervous System, and persists through to adulthood. Oligodendrocyte progenitor cell (OPC) enriched cultures are usefull tools for in vitro studies as well as for cell replacement therapies for treating demyelination diseases. We used Subventricular Zone-derived NSC/NPC primary cultures from newborn mice and compared the effects of different growth factor combinations on cell proliferation and OPC yield. The Platelet Derived Growth Factor-AA and BB homodimers had a positive and significant impact on OPC generation. Furthermore, heparin addition to the culture media contributed to further increase overall culture yields. The OPC generated by this protocol were able to mature into Myelin Basic Protein-expressing cells and to interact with neurons in an in vitro co-culture system. As a whole, we describe an optimized in vitro method for increasing OPC. PMID:25837625
Franco, Paula G; Pasquini, Juana M; Silvestroff, Lucas
Neural Stem and Progenitor Cells (NSC/NPC) are gathering tangible recognition for their uses in cell therapy and cell replacement therapies for human disease, as well as a model system to continue research on overall neural developmental processes in vitro. The Subventricular Zone is one of the largest NSC/NPC niches in the developing mammalian Central Nervous System, and persists through to adulthood. Oligodendrocyte progenitor cell (OPC) enriched cultures are usefull tools for in vitro studies as well as for cell replacement therapies for treating demyelination diseases. We used Subventricular Zone-derived NSC/NPC primary cultures from newborn mice and compared the effects of different growth factor combinations on cell proliferation and OPC yield. The Platelet Derived Growth Factor-AA and BB homodimers had a positive and significant impact on OPC generation. Furthermore, heparin addition to the culture media contributed to further increase overall culture yields. The OPC generated by this protocol were able to mature into Myelin Basic Protein-expressing cells and to interact with neurons in an in vitro co-culture system. As a whole, we describe an optimized in vitro method for increasing OPC.
Full Text Available Understanding of processes driving bacterial speciation requires examination of closely related, recently diversified lineages. To gain an insight into diversification of bacteria, we conducted comparative genomic analysis of two lineages of bioluminescent symbionts, Photobacterium leiognathi and 'P. mandapamensis'. The two lineages are evolutionary and ecologically closely related. Based on the methods used in bacterial taxonomy for classification of new species (DNA-DNA hybridization and ANI, genetic relatedness of the two lineages is at a cut-off point for species delineation. In this study, we obtained the whole genome sequence of a representative P. leiognathi strain lrivu.4.1, and compared it to the whole genome sequence of 'P. mandapamensis' svers.1.1. Results of the comparative genomic analysis suggest that P. leiognathi has a more plastic genome and acquired genes horizontally more frequently than 'P. mandapamensis'. We predict that different rates of recombination and gene acquisition contributed to diversification of the two lineages. Analysis of lineage-specific sequences in 25 strains of P. leiognathi and 'P. mandapamensis' found no evidence that bioluminescent symbioses with specific host animals have played a role in diversification of the two lineages.
Urbanczyk, Henryk; Urbanczyk, Yoshiko; Hayashi, Tetsuya; Ogura, Yoshitoshi
Understanding of processes driving bacterial speciation requires examination of closely related, recently diversified lineages. To gain an insight into diversification of bacteria, we conducted comparative genomic analysis of two lineages of bioluminescent symbionts, Photobacterium leiognathi and 'P. mandapamensis'. The two lineages are evolutionary and ecologically closely related. Based on the methods used in bacterial taxonomy for classification of new species (DNA-DNA hybridization and ANI), genetic relatedness of the two lineages is at a cut-off point for species delineation. In this study, we obtained the whole genome sequence of a representative P. leiognathi strain lrivu.4.1, and compared it to the whole genome sequence of 'P. mandapamensis' svers.1.1. Results of the comparative genomic analysis suggest that P. leiognathi has a more plastic genome and acquired genes horizontally more frequently than 'P. mandapamensis'. We predict that different rates of recombination and gene acquisition contributed to diversification of the two lineages. Analysis of lineage-specific sequences in 25 strains of P. leiognathi and 'P. mandapamensis' found no evidence that bioluminescent symbioses with specific host animals have played a role in diversification of the two lineages.
Orduz, David; Maldonado, Paloma P; Balia, Maddalena; Vélez-Fort, Mateo; de Sars, Vincent; Yanagawa, Yuchio; Emiliani, Valentina; Angulo, Maria Cecilia
NG2 cells, oligodendrocyte progenitors, receive a major synaptic input from interneurons in the developing neocortex. It is presumed that these precursors integrate cortical networks where they act as sensors of neuronal activity. We show that NG2 cells of the developing somatosensory cortex form a transient and structured synaptic network with interneurons that follows its own rules of connectivity. Fast-spiking interneurons, highly connected to NG2 cells, target proximal subcellular domains containing GABAA receptors with γ2 subunits. Conversely, non-fast-spiking interneurons, poorly connected with these progenitors, target distal sites lacking this subunit. In the network, interneuron-NG2 cell connectivity maps exhibit a local spatial arrangement reflecting innervation only by the nearest interneurons. This microcircuit architecture shows a connectivity peak at PN10, coinciding with a switch to massive oligodendrocyte differentiation. Hence, GABAergic innervation of NG2 cells is temporally and spatially regulated from the subcellular to the network level in coordination with the onset of oligodendrogenesis.
Mecha, M; Torrao, A S; Mestre, L; Carrillo-Salinas, F J; Mechoulam, R; Guaza, C
Cannabidiol (CBD) is the most abundant cannabinoid in Cannabis sativa that has no psychoactive properties. CBD has been approved to treat inflammation, pain and spasticity associated with multiple sclerosis (MS), of which demyelination and oligodendrocyte loss are hallmarks. Thus, we investigated the protective effects of CBD against the damage to oligodendrocyte progenitor cells (OPCs) mediated by the immune system. Doses of 1 μM CBD protect OPCs from oxidative stress by decreasing the production of reactive oxygen species. CBD also protects OPCs from apoptosis induced by LPS/IFNγ through the decrease of caspase 3 induction via mechanisms that do not involve CB1, CB2, TRPV1 or PPARγ receptors. Tunicamycin-induced OPC death was attenuated by CBD, suggesting a role of endoplasmic reticulum (ER) stress in the mode of action of CBD. This protection against ER stress-induced apoptosis was associated with reduced phosphorylation of eiF2α, one of the initiators of the ER stress pathway. Indeed, CBD diminished the phosphorylation of PKR and eiF2α induced by LPS/IFNγ. The pro-survival effects of CBD in OPCs were accompanied by decreases in the expression of ER apoptotic effectors (CHOP, Bax and caspase 12), and increased expression of the anti-apoptotic Bcl-2. These findings suggest that attenuation of the ER stress pathway is involved in the 'oligoprotective' effects of CBD during inflammation.
Guowei Zhu; Chongran Sun; Weiguo Liu
In this study,cells from the cerebral cortex of fetal rats at pregnant 16 days were harvested and cultured with 20 μg/L neurotrophin-3.After 7 days of culture,immunocytochemical staining showed that,22.4％ of cells were positive for nestin,10.5％ were positive for β-Ⅲ tubulin (neuronal marker),and 60.6％ were positive for glial fibrillary acidic protein,but no cells were positive for O4 (oligodendrocytic marker).At 14 days,there were 5.6％ nestin-,9.6％ β-Ⅲ tubulin-,81.1％ glial fibrillary acidic protein-,and 2.2％ O4-positive cells.In cells not treated with neurotrophin-3,some were nestin-positive,while the majority showed positive staining for glial fibrillary acidic protein.Our experimental findings indicate that neurotrophin-3 is a crucial factor for inducing neural stem cells differentiation into neurons and oligodendrocytes.
Full Text Available Oligodendrocyte precursor cells (OPCs are a unique type of glial cells that function as oligodendrocyte progenitors while constantly proliferating in the normal condition from rodents to humans. However, the functional roles they play in the adult brain are largely unknown. In this study, we focus on the manner of OPC proliferation in the hippocampus of the young adult mice. Here we report that there are oscillatory dynamics in OPC proliferation that differ from neurogenesis in the subgranular zone (SGZ; the former showed S-phase and M-phase peaks in the resting and active periods, respectively, while the latter only exhibited M-phase peak in the active period. There is coincidence between different modes of proliferation and expression of cyclin proteins that are crucial for cell cycle; cyclin D1 is expressed in OPCs, while cyclin D2 is observed in neural stem cells. Similar to neurogenesis, the proliferation of hippocampal OPCs was enhanced by voluntary exercise that leads to an increase in neuronal activity in the hippocampus. These data suggest an intriguing control of OPC proliferation in the hippocampus.
Full Text Available Demyelination contributes to the functional impairment of irradiation injured spinal cord. One potential therapeutic strategy involves replacing the myelin-forming cells. Here, we asked whether transplantation of Olig2(+-GFP(+-oligodendrocyte precursor cells (OPCs, which are derived from Olig2-GFP-mouse embryonic stem cells (mESCs, could enhance remyelination and functional recovery after spinal cord irradiation injury. We differentiated Olig2-GFP-mESCs into purified Olig2(+-GFP(+-OPCs and transplanted them into the rats' cervical 4-5 dorsal spinal cord level at 4 months after irradiation injury. Eight weeks after transplantation, the Olig2(+-GFP(+-OPCs survived and integrated into the injured spinal cord. Immunofluorescence analysis showed that the grafted Olig2(+-GFP(+-OPCs primarily differentiated into adenomatous polyposis coli (APC(+ oligodendrocytes (54.6±10.5%. The staining with luxol fast blue, hematoxylin & eosin (LFB/H&E and electron microscopy demonstrated that the engrafted Olig2(+-GFP(+-OPCs attenuated the demyelination resulted from the irradiation. More importantly, the recovery of forelimb locomotor function was enhanced in animals receiving grafts of Olig2(+-GFP(+-OPCs. We concluded that OPC transplantation is a feasible therapy to repair the irradiated lesions in the central nervous system (CNS.
Full Text Available Fibroblast growth factor (Fgf signaling plays crucial roles in various developmental processes including those in the brain. We examined the role of Fgf16 in the formation of the zebrafish brain. The knockdown of fgf16 decreased cell proliferation in the forebrain and midbrain. fgf16 was also essential for development of the ventral telencephalon and diencephalon, whereas fgf16 was not required for dorsoventral patterning in the midbrain. fgf16 was additionally required for the specification and differentiation of γ-aminobutyric acid (GABAergic interneurons and oligodendrocytes, but not for those of glutamatergic neurons in the forebrain. Cross talk between Fgf and Hedgehog (Hh signaling was critical for the specification of GABAergic interneurons and oligodendrocytes. The expression of fgf16 in the forebrain was down-regulated by the inhibition of Hh and Fgf19 signaling, but not by that of Fgf3/Fgf8 signaling. The fgf16 morphant phenotype was similar to that of the fgf19 morphant and embryos blocked Hh signaling. The results of the present study indicate that Fgf16 signaling, which is regulated by the downstream pathways of Hh-Fgf19 in the forebrain, is involved in forebrain development.
Satoh, J; Kim, S U; Kastrukoff, L F
The cytotoxic activity of killer (K) cells against enriched cultures of bovine oligodendrocytes (BOL) was investigated in multiple sclerosis (MS) and controls. Human K cells mediated cytotoxicity to primary cultures of BOL in the presence of anti-BOL antiserum in all study groups, while BOL were resistant to human natural killer (NK) cells. Cytotoxic activity was significantly reduced in MS when compared to age-matched normal controls but not when compared to other neurologic disease (OND) patients. K cell-mediated lysis of BOL could also be induced with anti-galactocerebroside antibody but not with other antibodies including those specific for OL antigens (myelin basic protein, proteolipid apoprotein, and 2',3'-cyclic nucleotide 3'-phosphodiesterase). Enrichment of the effector population indicated that antibody-dependent cell-mediated cytotoxicity (ADCC) to BOL was mediated by large granular lymphocytes, and the effector population was further characterized by flow cytometry. The effector cells mediating ADCC could be inhibited by protein A of Staphylococcus aureus, and by K562 cells in cold competition assay. These observations indicate that oligodendrocytes are resistant to NK cells but are susceptible to cytolysis mediated by K cells. This may represent a potentially important immune mechanism in the pathogenesis of MS.
Vaughan, Andrew E; Brumwell, Alexis N; Xi, Ying; Gotts, Jeffrey E; Brownfield, Doug G; Treutlein, Barbara; Tan, Kevin; Tan, Victor; Liu, Feng Chun; Looney, Mark R; Matthay, Michael A; Rock, Jason R; Chapman, Harold A
Broadly, tissue regeneration is achieved in two ways: by proliferation of common differentiated cells and/or by deployment of specialized stem/progenitor cells. Which of these pathways applies is both organ- and injury-specific. Current models in the lung posit that epithelial repair can be attributed to cells expressing mature lineage markers. By contrast, here we define the regenerative role of previously uncharacterized, rare lineage-negative epithelial stem/progenitor (LNEP) cells present within normal distal lung. Quiescent LNEPs activate a ΔNp63 (a p63 splice variant) and cytokeratin 5 remodelling program after influenza or bleomycin injury in mice. Activated cells proliferate and migrate widely to occupy heavily injured areas depleted of mature lineages, at which point they differentiate towards mature epithelium. Lineage tracing revealed scant contribution of pre-existing mature epithelial cells in such repair, whereas orthotopic transplantation of LNEPs, isolated by a definitive surface profile identified through single-cell sequencing, directly demonstrated the proliferative capacity and multipotency of this population. LNEPs require Notch signalling to activate the ΔNp63 and cytokeratin 5 program, and subsequent Notch blockade promotes an alveolar cell fate. Persistent Notch signalling after injury led to parenchymal 'micro-honeycombing' (alveolar cysts), indicative of failed regeneration. Lungs from patients with fibrosis show analogous honeycomb cysts with evidence of hyperactive Notch signalling. Our findings indicate that distinct stem/progenitor cell pools repopulate injured tissue depending on the extent of the injury, and the outcomes of regeneration or fibrosis may depend in part on the dynamics of LNEP Notch signalling.
Fressinaud, Catherine; Eyer, Joël
During multiple sclerosis (MS), the main axon cystoskeleton proteins, neurofilaments (NF), are altered, and their release into the cerebrospinal fluid correlates with disease severity. The role of NF in the extraaxonal location is unknown. Therefore, we tested whether synthetic peptides corresponding to the tubulin-binding site (TBS) sequence identified on light NF chain (NFL-TBS.40-63) and keratin (KER-TBS.1-24), which could be released during MS, modulate remyelination in vitro. Biotinylated NFL-TBS.40-63, NFL-Scramble2, and KER-TBS.1-54 (1-100 μM, 24 hr) were added to rat oligodendrocyte (OL) and astrocyte (AS) cultures, grown in chemically defined medium. Proliferation and differentiation were characterized by using specific antibodies (A2B5, CNP, MBP, GFAP) and compared with untreated cultures. Lysophosphatidyl choline (LPC; 2 × 10(-5) M) was used to induce OL death and to test the effects of TBS peptides under these conditions. NFL-TBS.40-63 significantly increased OL differentiation and maturation, with more CNP(+) and MBP(+) cells characterized by numerous ramified processes, along with myelin balls. When OL were challenged with LPC, concomitant treatment with NFL-TBS.40-63 rescued more than 50% of OL compared with cultures treated with LPC only. Proliferation of OL progenitors was not affected, nor were AS proliferation and differentiation. NFL-TBS.40-63 peptide induces specific effects in vitro, increasing OL differentiation and maturation without altering AS fate. In addition, it partially protects OL from demyelinating injury. Thus release of NFL-TBS.40-63 caused by axonal damage in vivo could improve repair through increased OL differentiation, which is a prerequisite for remyelination. Copyright © 2013 Wiley Periodicals, Inc.
Cheng, Tongfei; Xue, Xindong; Fu, Jianhua
OLIG1 is an oligodendrocyte (OL) transcription factor, which can contribute to the proliferation and differentiation of OLs, and the maturation of myelin. The aim of this study was to clarify the role of OLIG1 in neonatal Sprague Dawley rats with periventricular leukomalacia (PVL), induced by hypoxia‑ischemia (HI). Newborn rats in the HI group were subjected to ligation of the right carotid artery, followed by 8% oxygen delivery for 2 h, while rats in the normoxia group were only subjected to isolation of the right carotid artery, without exposure to hypoxia. Samples of brain tissue from rats in both groups were collected at 1, 3, 7, 14 and 21 days. In the HI group, observation by transmission electron microscopy (TEM) revealed OLs with a damaged nuclear membrane, cellular atrophy, deformation and necrosis, and cells in myelin with a high number of small vacuoles. A double‑label immunofluorescence assay revealed the translocation of OLIG1 from the cytoplasm to the nucleus, while western blot and reverse transcription‑quantitative polymerase chain reaction assays showed that there is a significant decrease, followed by an increase, in the gene and protein expression levels of OLIG1 and myelin basic protein (MBP). Despite the increase at the late stages of HI, the final levels of these proteins remained lower than the corresponding levels in the normoxia group. In conclusion, the decreased protein expression of OLIG1 following HI plays an important role in inhibiting the development and maturation of OLs and myelin. Although OLIG1 may, via its nuclear translocation, promote the growth and development of myelin to a certain extent, this factor fails to fully repair injured myelin.
Ohmura, Sakie; Mizuno, Seiya; Oishi, Hisashi; Ku, Chia-Jui; Hermann, Mary; Hosoya, Tomonori; Takahashi, Satoru; Engel, James Douglas
The transcription factor GATA3 is essential for the genesis and maturation of the T cell lineage, and GATA3 dysregulation has pathological consequences. Previous studies have shown that GATA3 function in T cell development is regulated by multiple signaling pathways and that the Notch nuclear effector, RBP-J, binds specifically to the Gata3 promoter. We previously identified a T cell-specific Gata3 enhancer (Tce1) lying 280 kb downstream from the structural gene and demonstrated in transgenic mice that Tce1 promoted T lymphocyte-specific transcription of reporter genes throughout T cell development; however, it was not clear if Tce1 is required for Gata3 transcription in vivo. Here, we determined that the canonical Gata3 promoter is insufficient for Gata3 transcriptional activation in T cells in vivo, precluding the possibility that promoter binding by a host of previously implicated transcription factors alone is responsible for Gata3 expression in T cells. Instead, we demonstrated that multiple lineage-affiliated transcription factors bind to Tce1 and that this enhancer confers T lymphocyte-specific Gata3 activation in vivo, as targeted deletion of Tce1 in a mouse model abrogated critical functions of this T cell-regulatory element. Together, our data show that Tce1 is both necessary and sufficient for critical aspects of Gata3 T cell-specific transcriptional activity.
Czepiel, Marcin; Leicher, Lasse; Becker, Katja; Boddeke, Erik; Copray, Sjef
Cell replacement therapy aiming at the compensation of lost oligodendrocytes and restoration of myelination in acquired or congenital demyelination disorders has gained considerable interest since the discovery of induced pluripotent stem cells (iPSCs). Patient-derived iPSCs provide an inexhaustible
Thyroid hormone (TH) may control the ratio of oligodendrocytes to astrocytes in white matter by acting on a common precursor of these two cell types. If so, then TH should produce an equal but opposite effect on the density of these two cells types across all TH levels. To test t...
Menichella, Daniela M; Majdan, Marta; Awatramani, Rajeshwar; Goodenough, Daniel A; Sirkowski, Erich; Scherer, Steven S; Paul, David L
Mice lacking the K+ channel Kir4.1 or both connexin32 (Cx32) and Cx47 exhibit myelin-associated vacuoles, raising the possibility that oligodendrocytes, and the connexins they express, contribute to recycling the K+ evolved during neuronal activity. To study this possibility, we first examined the effect of neuronal activity on the appearance of vacuoles in mice lacking both Cx32 and Cx47. The size and number of myelin vacuoles was dramatically increased when axonal activity was increased, by either a natural stimulus (eye opening) or pharmacological treatment. Conversely, myelin vacuoles were dramatically reduced when axonal activity was suppressed. Second, we used genetic complementation to test for a relationship between the function of Kir4.1 and oligodendrocyte connexins. In a Cx32-null background, haploinsufficiency of either Cx47 or Kir4.1 did not affect myelin, but double heterozygotes developed vacuoles, consistent with the idea that oligodendrocyte connexins and Kir4.1 function in a common pathway. Together, these results implicate oligodendrocytes and their connexins as having critical roles in the buffering of K+ released during neuronal activity.
Gao, Feng; Bonsignori, Mattia; Liao, Hua-Xin; Kumar, Amit; Xia, Shi-Mao; Lu, Xiaozhi; Cai, Fangping; Hwang, Kwan-Ki; Song, Hongshuo; Zhou, Tongqing; Lynch, Rebecca M; Alam, S Munir; Moody, M Anthony; Ferrari, Guido; Berrong, Mark; Kelsoe, Garnett; Shaw, George M; Hahn, Beatrice H; Montefiori, David C; Kamanga, Gift; Cohen, Myron S; Hraber, Peter; Kwong, Peter D; Korber, Bette T; Mascola, John R; Kepler, Thomas B; Haynes, Barton F
Development of strategies for induction of HIV-1 broadly neutralizing antibodies (bnAbs) by vaccines is a priority. Determining the steps of bnAb induction in HIV-1-infected individuals who make bnAbs is a key strategy for immunogen design. Here, we study the B cell response in a bnAb-producing individual and report cooperation between two B cell lineages to drive bnAb development. We isolated a virus-neutralizing antibody lineage that targeted an envelope region (loop D) and selected virus escape mutants that resulted in both enhanced bnAb lineage envelope binding and escape mutant neutralization-traits associated with increased B cell antigen drive. Thus, in this individual, two B cell lineages cooperated to induce the development of bnAbs. Design of vaccine immunogens that simultaneously drive both helper and broadly neutralizing B cell lineages may be important for vaccine-induced recapitulation of events that transpire during the maturation of neutralizing antibodies in HIV-1-infected individuals.
Wong, Agnes W; Giuffrida, Lauren; Wood, Rhiannon; Peckham, Haley; Gonsalvez, David; Murray, Simon S; Hughes, Richard A; Xiao, Junhua
Brain-derived neurotrophic factor (BDNF) plays critical roles in the development and maintenance of the central (CNS) and peripheral nervous systems (PNS). BDNF exerts its biological effects via tropomyosin-related kinase B (TrkB) and the p75 neurotrophin receptor (p75NTR). We have recently identified that BDNF promotes CNS myelination via oligodendroglial TrkB receptors. In order to selectively target TrkB to promote CNS myelination, we have used a putative TrkB agonist, a small multicyclic peptide (tricyclic dimeric peptide 6, TDP6) previously described by us that structurally mimics a region of BDNF that binds TrkB. We confirmed that TDP6 acts as a TrkB agonist as it provoked autophosphorylation of TrkB and its downstream signalling effector extracellular related-kinase 1 and 2 (Erk1/2) in primary oligodendrocytes. Using an in vitro myelination assay, we show that TDP6 significantly promotes myelination by oligodendrocytes in vitro, as evidenced by enhanced myelin protein expression and an increased number of myelinated axonal segments. In contrast, a second, structurally distinct BDNF mimetic (cyclo-dPAKKR) that targets p75NTR had no effect upon oligodendrocyte myelination in vitro, despite the fact that cyclo-dPAKKR is a very effective promoter of peripheral (Schwann cell) myelination. The selectivity of TDP6 was further verified by using TrkB-deficient oligodendrocytes, in which TDP6 failed to promote myelination, indicating that the pro-myelinating effect of TDP6 is oligodendroglial TrkB-dependent. Together, our results demonstrate that TDP6 is a novel BDNF mimetic that promotes oligodendrocyte myelination in vitro via targeting TrkB.
Li, Haitao; Marijanovic, Inga; Kronenberg, Mark S; Erceg, Ivana; Stover, Mary Louise; Velonis, Dimitrios; Mina, Mina; Heinrich, Jelica Gluhak; Harris, Stephen E; Upholt, William B; Kalajzic, Ivo; Lichtler, Alexander C
Our laboratory and others have shown that overexpression of Dlx5 stimulates osteoblast differentiation. Dlx5(-/-)/Dlx6(-/-) mice have more severe craniofacial and limb defects than Dlx5(-/-), some of which are potentially due to defects in osteoblast maturation. We wished to investigate the degree to which other Dlx genes compensate for the lack of Dlx5, thus allowing normal development of the majority of skeletal elements in Dlx5(-/-) mice. Dlx gene expression in cells from different stages of the osteoblast lineage isolated by FACS sorting showed that Dlx2, Dlx5 and Dlx6 are expressed most strongly in less mature osteoblasts, whereas Dlx3 is very highly expressed in differentiated osteoblasts and osteocytes. In situ hybridization and Northern blot analysis demonstrated the presence of endogenous Dlx3 mRNA within osteoblasts and osteocytes. Dlx3 strongly upregulates osteoblastic markers with a potency comparable to Dlx5. Cloned chick or mouse Dlx6 showed stimulatory effects on osteoblast differentiation. Our results suggest that Dlx2 and Dlx6 have the potential to stimulate osteoblastic differentiation and may compensate for the absence of Dlx5 to produce relatively normal osteoblastic differentiation in Dlx5 knockout mice, while Dlx3 may play a distinct role in late stage osteoblast differentiation and osteocyte function.
Kamasawa, N; Sik, A; Morita, M; Yasumura, T; Davidson, K G V; Nagy, J I; Rash, J E
The subcellular distributions and co-associations of the gap junction-forming proteins connexin 47 and connexin 32 were investigated in oligodendrocytes of adult mouse and rat CNS. By confocal immunofluorescence light microscopy, abundant connexin 47 was co-localized with astrocytic connexin 43 on oligodendrocyte somata, and along myelinated fibers, whereas connexin 32 without connexin 47 was co-localized with contactin-associated protein (caspr) in paranodes. By thin-section transmission electron microscopy, connexin 47 immunolabeling was on the oligodendrocyte side of gap junctions between oligodendrocyte somata and astrocytes. By freeze-fracture replica immunogold labeling, large gap junctions between oligodendrocyte somata and astrocyte processes contained much more connexin 47 than connexin 32. Along surfaces of internodal myelin, connexin 47 was several times as abundant as connexin 32, and in the smallest gap junctions, often occurred without connexin 32. In contrast, connexin 32 was localized without connexin 47 in newly-described autologous gap junctions in Schmidt-Lanterman incisures and between paranodal loops bordering nodes of Ranvier. Thus, connexin 47 in adult rodent CNS is the most abundant connexin in most heterologous oligodendrocyte-to-astrocyte gap junctions, whereas connexin 32 is the predominant if not sole connexin in autologous ("reflexive") oligodendrocyte gap junctions. These results clarify the locations and connexin compositions of heterologous and autologous oligodendrocyte gap junctions, identify autologous gap junctions at paranodes as potential sites for modulating paranodal electrical properties, and reveal connexin 47-containing and connexin 32-containing gap junctions as conduits for long-distance intracellular and intercellular movement of ions and associated osmotic water. The autologous gap junctions may regulate paranodal electrical properties during saltatory conduction. Acting in series and in parallel, autologous and
Fulton, Daniel; Paez, Pablo M; Campagnoni, Anthony T
It has become clear that the products of several of the earliest identified myelin protein genes perform functions that extend beyond the myelin sheath. Interestingly, these myelin proteins, which comprise proteolipid protein, 2',3'-cyclic nucleotide 3'-phosphodiesterase and the classic and golli MBPs (myelin basic proteins), play important roles during different stages of oligodendroglial development. These non-myelin-related functions are varied and include roles in the regulation of process outgrowth, migration, RNA transport, oligodendrocyte survival and ion channel modulation. However, despite the wide variety of cellular functions performed by the different myelin genes, the route by which they achieve these many functions seems to converge upon a common mechanism involving Ca(2+) regulation, cytoskeletal rearrangements and signal transduction. In the present review, the newly emerging functions of these myelin proteins will be described, and these will then be discussed in the context of their contribution to oligodendroglial development.
Anthony T Campagnoni
Full Text Available It has become clear that the products of several of the earliest identified myelin protein genes perform functions that extend beyond the myelin sheath. Interestingly, these myelin proteins, which comprise proteolipid protein, 2′,3′-cyclic nucleotide 3′-phosphodiesterase and the classic and golli MBPs (myelin basic proteins, play important roles during different stages of oligodendroglial development. These non-myelin-related functions are varied and include roles in the regulation of process outgrowth, migration, RNA transport, oligodendrocyte survival and ion channel modulation. However, despite the wide variety of cellular functions performed by the different myelin genes, the route by which they achieve these many functions seems to converge upon a common mechanism involving Ca2+ regulation, cytoskeletal rearrangements and signal transduction. In the present review, the newly emerging functions of these myelin proteins will be described, and these will then be discussed in the context of their contribution to oligodendroglial development.
Zhu, Bangfu; Nicholls, Matthew; Gu, Yu; Zhang, Gaofeng; Zhao, Chao; Franklin, Robin J M; Song, Bing
The guided migration of neural cells is essential for repair in the central nervous system (CNS). Oligodendrocyte progenitor cells (OPCs) will normally migrate towards an injury site to re-sheath demyelinated axons; however the mechanisms underlying this process are not well understood. Endogenous electric fields (EFs) are known to influence cell migration in vivo, and have been utilised in this study to direct the migration of OPCs isolated from neonatal Sprague-Dawley rats. The OPCs were exposed to physiological levels of electrical stimulation, and displayed a marked electrotactic response that was dependent on β1 integrin, one of the key subunits of integrin receptors. We also observed that F-actin, an important component of the cytoskeleton, was re-distributed towards the leading edge of the migrating cells, and that this asymmetric rearrangement was associated with β1 integrin function.
Pang, Yi; Fan, Lir-Wan; Tien, Lu-Tai; Dai, Xuemei; Zheng, Baoying; Cai, Zhengwei; Lin, Rick C S; Bhatt, Abhay
Oligodendrocyte (OL) development relies on many extracellular cues, most of which are secreted cytokines from neighboring neural cells. Although it is generally accepted that both astrocytes and microglia are beneficial for OL development, there is a lack of understanding regarding whether astrocytes and microglia play similar or distinct roles. The current study examined the effects of astrocytes and microglia on OL developmental phenotypes including cell survival, proliferation, differentiation, and myelination in vitro. Our data reveal that, although both astrocytes- and microglia-conditioned medium (ACDM and MCDM, respectively) protect OL progenitor cells (OPCs) against growth factor withdrawal-induced apoptosis, ACDM is significantly more effective than MCDM in supporting long-term OL survival. In contrast, MCDM preferentially promotes OL differentiation and myelination. These differential effects of ACDM and MCDM on OL development are highlighted by distinct pattern of cytokine/growth factors in the conditioned medium, which correlates with differentially activated intracellular signaling pathways in OPCs upon exposure to the conditioned medium.
John C Gensel
Full Text Available Excess glutamate release and associated neurotoxicity contributes to cell death after spinal cord injury (SCI. Indeed, delayed administration of glutamate receptor antagonists after SCI in rodents improves tissue sparing and functional recovery. Despite their therapeutic potential, most glutamate receptor antagonists have detrimental side effects and have largely failed clinical trials. Topiramate is an AMPA-specific, glutamate receptor antagonists that is FDA-approved to treat CNS disorders. In the current study we tested whether topiramate treatment is neuroprotective after cervical contusion injury in rats. We report that topiramate, delivered 15-minutes after SCI, increases tissue sparing and preserves oligodendrocytes and neurons when compared to vehicle treatment. In addition, topiramate is more effective than the AMPA-receptor antagonist, NBQX. To the best of our knowledge, this is the first report documenting a neuroprotective effect of topiramate treatment after spinal cord injury.
Terzi, Yunus Kasim; Oğuzkan-Balci, Sibel; Anlar, Banu; Erdoğan-Bakar, Emel; Ayter, Sükriye
Neurofibromatosis type 1 (NF1) is an autosomal dominant disease where phenotypic heterogeneity is explained by the effect of modifier genes. Thirty to 65% of patients have learning disability. The oligodendrocyte myelin glycoprotein (OMGP) gene located within the neurofibromatosis type 1 (NF1) gene might affect the phenotype of learning disability because it is expressed in the brain, and OMGP gene mutations have been associated with cognitive disturbances. We analyzed the OMGP gene in NF1 patients with and without learning disability (n = 50 each) and healthy controls (n = 100). The allele distribution of OMGP62 polymorphism was not significantly different between the groups (p = 0.447). These results do not support a relationship between the OMGP gene and the learning disability phenotype observed in NF1. Other modifying genes, post-translational modifications or receptor interactions might be involved in the phenotypic variability of NF1.
Stark, Simone; Schuller, Alexandra; Sifringer, Marco; Gerstner, Bettina; Brehmer, Felix; Weber, Sven; Altmann, Rodica; Obladen, Michael; Buhrer, Christoph; Felderhoff-Mueser, Ursula
Recent evidence suggests oxygen as a powerful trigger for cell death in the immature white matter, leading to periventricular leukomalacia (PVL) as a cause of adverse neurological outcome in survivors of preterm birth. This oligodendrocyte (OL) death is associated with oxidative stress, upregulation of apoptotic signaling factors (i.e., Fas, caspase-3) and decreased amounts of neurotrophins. In search of neuroprotective strategies we investigated whether the polysulfonated urea derivative suramin, recently identified as a potent inhibitor of Fas signaling, affords neuroprotection in an in vitro model of hyperoxia-induced injury to immature oligodendrocytes. Immature OLs (OLN-93) were subjected to 80% hyperoxia (48 h) in the presence or absence of suramin (0, 30, 60, 120 microM). Cell death was assessed by flow cytometry (Annexin V, caspase-3 activity assay) and immunohistochemistry for activated caspase-3. Immunoblotting for the death receptor Fas, cleaved caspase-8 and the phosphorylated isoform of the serine-threonin kinase Akt (pAkt) was performed. Suramin lead to OL apoptosis and potentiated hyperoxia-induced injury in a dose-dependent manner. Immunoblotting revealed increased Fas and caspase-8 expression by suramin treatment. This effect was significantly enhanced when suramin was combined with hyperoxia. Furthermore, pAkt levels decreased following suramin exposure, indicating interference with neurotrophin-dependent growth factor signaling. These data indicate that suramin causes apoptotic cell death and aggravates hyperoxia-induced cell death in immature OLs. Its mechanism of action includes an increase of previously described hyperoxia-induced expression of pro-apoptotic factors and deprivation of growth factor dependent signaling components.
刘刚; 陈应柱; 赵合庆; 包仕尧
Alzhelmer's disease (AD) is an important neurodegenerative disease. Recent evidence has indicated that the production and loss of the myelin,sheath are associated with AD because the particular vulnerability of oligodendrocytes produced in the late stage makes the loss of the myelin sheath take a core position in the changes of the earliest stage of AD. The loss of the myelin sheath disrupts synchronization of impulses on which normal brain functions highly depend, and ultimately results in the function disruption of cortical association regions and subsequent neuronal loss. Meanwfiile, there are diverse mechanisms that make oligodendrocytes degeneration exist in the brains of AD. Therefore, elucidating its specific mechanism may help better understanding of AD, and thus provide some help for its treatment.%Alzheimer病(AD)是一种重要的神经退行性疾病.最近的证据表明,髓鞘形成和随后的脱失与AD有关,因为晚期产生的少突胶质细胞的独特易损性使髓鞘脱失在AD早期改变中占据核心位置.髓鞘脱失破坏了高度依赖神经冲动同步化的大脑功能,最终导致皮质联合区域功能的断联和随后的神经元脱失.同时,在AD大脑中存在多种使少突胶质细胞变性的机制.因此,阐明其具体机制可帮助更好地了解AD,从而为其治疗提供一定的帮助.
The paper aims to improve the knowledge of the empirical properties of the long maturity region of the forward rate curve. Firstly, the theoretical negative correlation between the slope at the long end of the forward rate curve and the term structure variance is recovered empirically and found...... to be statistically significant. Secondly, the expectations hypothesis is analyzed for the long maturity region of the forward rate curve using "forward rate" regressions. The expectations hypothesis is numerically close to being accepted but is statistically rejected. The findings provide mixed support...
The bachelor thesis deals with school maturity of children and is aimed at pre-school children at the age of 6 years or, if necessary, older. The aim of this thesis is to capture the differences between children who start a year later than they were supposed to and children who went to enrolment for the first time and present the reasons for postponing the start of the school attendance. The theoretical part focuses on the issue of maturity of pre-school children and also deals with their rea...
Zhu, Chang; Yao, Wen-Long; Tan, Wei; Zhang, Chuan-Han
Evidence has shown that stromal cell-derived factor (SDF-1/CXCL12) plays an important role in maintaining adult neural progenitor cells (NPCs). SDF-1 is also known to enhance recovery by recruiting NPCs to damaged regions and recent studies have revealed that SDF-1α exhibits pleiotropism, thereby differentially affecting NPC subpopulations. In this study, we investigated the role of SDF-1 in in vitro NPC self-renewal, proliferation and differentiation, following treatment with different concentrations of SDF-1 or a CXCR4 antagonist, AMD3100. We observed that AMD3100 inhibited the formation of primary neurospheres. However, SDF-1 and AMD3100 exhibited no effect on proliferation upon inclusion of growth factors in the media. Following growth factor withdrawal, AMD3100 and SDF-1 treatment resulted in differential effects on NPC proliferation. SDF-1, at a concentration of 500ng/ml, resulted in an increase in the relative proportion of oligodendrocytes following growth factor withdrawal-induced differentiation. Using CXCR4 knockout mice, we observed that SDF-1 affected NPC proliferation in the sub-ventricular zone (SVZ). We also investigated the occurrence of differential CXCR4 expression at different stages during lineage progression. These results clearly indicate that signaling interactions between SDF-1 and CXCR4 play an important role in adult SVZ lineage cell proliferation and differentiation.
Dominant Air Power: Design For Tomorrow…Deliver Today 2 TECHNOLOGY MATURITY CONFERENCE • ONE DEFINITION OF MATURITY – GOOD JUDGEMENT COMES FROM...EXPERIENCE—EXPERIENCE COMES FROM BAD JUDGEMENT Dominant Air Power: Design For Tomorrow…Deliver Today 3 TECHNOLOGY MATURITY CONFERENCE • THIS WILL BE A...2008 TECHNOLOGY MATURITY CONFERENCE “ TECHNOLOGY MATURITY IS TECHNOLOGY SUPERIORITY” Aeronautical Systems Center Dr. Tom Christian ASC/EN, WPAFB OH
This thesis consists of nine chapters, divided over five parts. PART I is an introduction and the last part contains the conclusions. The remaining, intermediate parts are: PART II: Developing a maturity model for chain digitisation. This part contains two related studies concerning the development
This thesis consists of nine chapters, divided over five parts. PART I is an introduction and the last part contains the conclusions. The remaining, intermediate parts are: PART II: Developing a maturity model for chain digitisation. This part contains two related studies concerning the development
Roos, Wouter H.; Gertsman, Ilya; May, Eric R.; Brooks III, Charles L.; Johnson, John E.; Wuite, Gijs J. L.
Capsid maturation with large-scale subunit reorganization occurs in virtually all viruses that use a motor to package nucleic acid into preformed particles. A variety of ensemble studies indicate that the particles gain greater stability during this process, however, it is unknown which material
Mathes, Eugene W.; Deuger, Donna J.
Jealousy may be perceived as either good or bad depending upon the moral maturity of the individual. To investigate this conclusion, a study was conducted testing two hypothesis: a positive relationship exists between conventional moral reasoning (reference to norms and laws) and the endorsement and level of jealousy; and a negative relationship…
Full Text Available Cellular barcoding and other single-cell lineage-tracing strategies form experimental methodologies for analysis of in vivo cell fate that have been instrumental in several significant recent discoveries. Due to the highly nonlinear nature of proliferation and differentiation, interrogation of the resulting data for evaluation of potential lineage pathways requires a new quantitative framework complete with appropriate statistical tests. Here, we develop such a framework, illustrating its utility by analyzing data from barcoded multipotent cells of the blood system. This application demonstrates that the data require additional paths beyond those found in the classical model, which leads us to propose that hematopoietic differentiation follows a loss of potential mechanism and to suggest further experiments to test this deduction. Our quantitative framework can evaluate the compatibility of lineage trees with barcoded data from any proliferating and differentiating cell system.
Shin, Jae-Won; Spinler, Kyle R.; Swift, Joe; Chasis, Joel A.; Mohandas, Narla; Discher, Dennis E.
Comparing human blood cell types, nuclear diversity is visually striking but unexplained: quasi-spherical nuclei in stem/progenitor cells and T cells contrast with multilobed nuclei in neutrophils, giant nuclei in megakaryocytes, and anuclear erythrocytes. We hypothesized broad roles for the major nuclear structure proteins—lamins—and developed mass spectrometry-calibrated intracellular flow cytometry to quantify lamin-A:B ratios. This ratio controls both nuclear viscoelasticity and cell traf...
WIN55, 212-2 promotes differentiation of oligodendrocyte precursor cells and improve remyelination through regulation of the phosphorylation level of the ERK 1/2 via cannabinoid receptor 1 after stroke-induced demyelination.
Sun, Jing; Fang, Yinquan; Chen, Tao; Guo, Jingjing; Yan, Jun; Song, Shu; Zhang, Luyong; Liao, Hong
In stroke, a common cause of neurological disability in adults is that the myelin sheaths are lost through the injury or death of mature oligodendrocytes, and the failure of remyelination may be often due to insufficient proliferation and differentiation of oligodendroglial progenitors. In the current study, we used middle cerebral artery occlusion (MCAO) to induced transient focal cerebral ischemia, and found that WIN55, 212-2 augmented actively proliferating oligodendrocytes measured by CC1 immunoreactive cells within the peri-infarct areas. To establish whether these effects were associated with changes in myelin formation, we analyzed the expression of myelin basic protein (MBP) and myelin ultrastructure. We found that WIN55, 212-2 showed more extensive remyelination than vehicle at 14 days post injection (dpi). The extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling pathway may be involved in OPCs differentiation. To determine the regulatory effect of WIN55, 212-2 post-treatment on phospho-ERK 1/2 (p-ERK 1/2) after ischemia/reperfusion, Western blot analysis was performed. We found that WIN55, 212-2 regulated the phosphorylation level of the ERK 1/2 to promote OPCs survival and differentiation. Notably, cannabinoid receptor 1 is coupled to the activation of the ERK cascade. Following rimonabant combined treatment, the effect of WIN55, 212-2 on regulating the phosphorylation level of the ERK 1/2 was reversed, and the effect of accelerated myelin formation was partially inhibited. Together, we first found that WIN55, 212-2 promoted OPCs differentiation and remyelination through regulation of the level of the p-ERK 1/2 via cannabinoid receptor 1.
KAMASAWA, N.; SIK, A.; Morita, M; Yasumura, T; Davidson, K. G. V.; Nagy, J.I.; RASH, J.E.
The subcellular distributions and co-associations of the gap junction-forming proteins connexin47 and connexin32 were investigated in oligodendrocytes of adult mouse and rat CNS. By confocal immunofluorescence light microscopy, abundant connexin47 was co-localized with astrocytic connexin43 on oligodendrocyte somata, and along myelinated fibers, whereas connexin32 without connexin47 was co-localized with contactin-associated protein (caspr) in paranodes. By thin-section transmission electron ...
Weil, D; Power, M A; Smith, S I; Li, C L
In the course of systematic cloning of protein tyrosine kinases (PTKs) expressed in hematopoietic stem and progenitor cells, we have identified the murine homologue of human Bmx. It encodes a protein containing the five domains characteristic of the Tec family of cytoplasmic src-related PTKs: pleckstrin homology (PH), Tec homology (TH), src homology 3 and 2 (SH3 and SH2), and tyrosine kinase (TK). In adults, Bmx expression was found primarily in bone marrow and at a lower level in lung and heart. During fetal development it was also found in the spleen at late stage of gestation and in neonates. Analysis of bone marrow subpopulations showed that Bmx was expressed in the progenitor cell population and maturing hematopoietic cells of the granulo/monocytic lineage where expression increased with maturation and differentiation. At the periphery, a high level of Bmx expression was also found in neutrophils and monocytes/macrophages. Bmx expression was not detected in the primitive hematopoietic stem cell population, and cells of the B-, T-, and erythroid-lineages. It was also not detected in most of the cell lines examined. Our results indicate that Bmx is another member of the Btk/Itk/Tec PTK family, which is predominantly expressed in the granulo-monocytic lineage within the hematopoietic system.
Full Text Available The concept is developed that modern technology, because of its relationship with pure science, can never really become mature, but will always grow as the pool of scientific knowledge grows. Parameters indicating to some extent the degree of technological prowess in a society are compared for a spectrum of countries. It is clear that in spite of some internationally outstanding successes. South Africa must be regarded on average as a developing society.
Natalya A. Uranova
Full Text Available Schizophrenia is believed to result from altered neuronal connectivity and impaired myelination. However, there are few direct evidence for myelin abnormalities in schizophrenia. We performed electron microscopic study of myelinated fibers and oligodendrocytes and morphometric study of myelinated fibers in the prefrontal cortex in gray and white matters in schizophrenia and normal controls. Six types of abnormal fibers and ultrastructural alterations of oligodendrocytes were found in schizophrenia. No significant group differences in area density of myelinated fibers were found. Frequency of pathological fibers was increased significantly in gray matter in young and elderly schizophrenia patients and in patients with predominantly positive symptoms. In contrast, in white matter, frequency of altered fibers was increased significantly in elderly patients, in patients with predominantly negative symptoms, and correlated with illness duration. Progressive alterations of myelinated fibers in white matter might be followed by alterations of myelinated fibers in gray matter in schizophrenia.
SUN, JING; Fang, Yin-quan; Ren, Hong; Tao CHEN; Guo, Jing-Jing; Yan, Jun; SONG, SHU; Zhang, Lu-yong; Liao, Hong
Aim: To explore whether the synthetic cannabinoid receptor agonist WIN55,212-2 could protect oligodendrocyte precursor cells (OPCs) in stroke penumbra, thereby providing neuroprotection following permanent focal cerebral ischemia in rats. Methods: Adult male SD rats were subjected to permanent middle cerebral artery occlusion (p-MCAO). The animals were administered WIN55,212-2 at 2 h, and sacrificed at 24 h after the ischemic insult. The infarct volumes and brain swelling were assessed. The e...
Paul C Guest
Full Text Available As a multifactorial disease, the underlying causes of schizophrenia require analysis by multiplex methods such as proteomics to allow identification of whole protein networks. Previous post-mortem proteomic studies on brain tissues from schizophrenia patients have demonstrated changes in activation of glycolytic and energy metabolism pathways. However, it is not known whether these changes occur in neurons or in glial cells. To address this question, we treated neuronal, astrocyte and oligodendrocyte cell lines with the NMDA receptor antagonist MK-801 and measured the levels of six glycolytic enzymes by Western blot analysis. MK-801 acts on the glutamatergic system and has been proposed as a pharmacological means of modeling schizophrenia. Treatment with MK-801 resulted in significant changes in the levels of glycolytic enzymes in all cell types. Most of the differences were found in oligodendrocytes, which had altered levels of hexokinase 1 (HK1, enolase 2 (ENO2, phosphoglycerate kinase (PGK and phosphoglycerate mutase 1 (PGAM1 after acute MK-801 treatment (8 hours, and HK1, ENO2, PGK and triosphosphate isomerase (TPI following long term treatment (72 hours. Addition of the antipsychotic clozapine to the cultures resulted in counter-regulatory effects to the MK-801 treatment by normalizing the levels of ENO2 and PGK in both the acute and long term cultures. In astrocytes, MK-801 affected only aldolase C (ALDOC under both acute conditions and HK1 and ALDOC following long term treatment, and TPI was the only enzyme affected under long term conditions in the neuronal cells. In conclusion, MK-801 affects glycolysis in oligodendrocytes to a larger extent than neuronal cells and this may be modulated by antipsychotic treatment. Although cell culture studies do not necessarily reflect the in vivo pathophysiology and drug effects within the brain, these results suggest that neurons, astrocytes and oligodendrocytes are affected differently in
Akçay, Erol; Van Cleve, Jeremy
Inclusive fitness has been the cornerstone of social evolution theory for more than a half-century and has matured as a mathematical theory in the past 20 years. Yet surprisingly for a theory so central to an entire field, some of its connections to evolutionary theory more broadly remain contentious or underappreciated. In this paper, we aim to emphasize the connection between inclusive fitness and modern evolutionary theory through the following fact: inclusive fitness is simply classical Darwinian fitness, averaged over social, environmental and demographic states that members of a gene lineage experience. Therefore, inclusive fitness is neither a generalization of classical fitness, nor does it belong exclusively to the individual. Rather, the lineage perspective emphasizes that evolutionary success is determined by the effect of selection on all biological and environmental contexts that a lineage may experience. We argue that this understanding of inclusive fitness based on gene lineages provides the most illuminating and accurate picture and avoids pitfalls in interpretation and empirical applications of inclusive fitness theory.
Debra A. Mayes
Full Text Available Patients with neurofibromatosis type 1 (NF1 and Costello syndrome Rasopathy have behavioral deficits. In NF1 patients, these may correlate with white matter enlargement and aberrant myelin. To model these features, we induced Nf1 loss or HRas hyperactivation in mouse oligodendrocytes. Enlarged brain white matter tracts correlated with myelin decompaction, downregulation of claudin-11, and mislocalization of connexin-32. Surprisingly, non-cell-autonomous defects in perivascular astrocytes and the blood-brain barrier (BBB developed, implicating a soluble mediator. Nitric oxide (NO can disrupt tight junctions and gap junctions, and NO and NO synthases (NOS1–NOS3 were upregulated in mutant white matter. Treating mice with the NOS inhibitor NG-nitro-L-arginine methyl ester or the antioxidant N-acetyl cysteine corrected cellular phenotypes. CNP-HRasG12V mice also displayed locomotor hyperactivity, which could be rescued by antioxidant treatment. We conclude that Nf1/Ras regulates oligodendrocyte NOS and that dysregulated NO signaling in oligodendrocytes can alter the surrounding vasculature. The data suggest that antioxidants may improve some behavioral deficits in Rasopathy patients.
Reissig, Chad J; Rabin, Richard A; Winter, Jerrold C; Dlugos, Cynthia A
Induction of mRNA or protein for immediate-early genes, such as c-fos, is used to identify brain areas, specific cell types, and neuronal circuits that become activated in response to various stimuli including psychoactive drugs. The objective of the present study was to identify the cell types in the prefrontal cortex in which lysergic acid diethylamide (d-LSD) induces c-Fos expression. Systemic administration of d-LSD resulted in a dose-dependent increase in c-Fos immunoreactivity. Although c-Fos-positive cells were found in all cortical layers, they were most numerous in layers III, IV, and V. d-LSD-induced c-Fos immunoreactivity was found in cells co-labeled with anti-neuron-specific enolase or anti-oligodendrocyte Oligo1. The Oligo1-labeled cells had small, round bodies and nuclear diameters characteristic of oligodendrocytes. Studies using confocal microscopy confirmed colocalization of c-Fos-labeled nuclei in NeuN-labeled neurons. Astrocytes and microglia labeled with glial fibrillary acidic protein antibody and OX-42 antibody, respectively, did not display LSD-induced c-Fos expression. Pyramidal neurons labeled with anti-neurofilament antibody also did not show induction of c-Fos immunoreactivity after systemic d-LSD administration. The present study demonstrates that d-LSD induced expression of c-Fos in the prefrontal cortex occurs in subpopulations of neurons and in oligodendrocytes, but not in pyramidal neurons, astrocytes, and microglia.
Matsumoto, Taro; Kano, Koichiro; Kondo, Daisuke; Fukuda, Noboru; Iribe, Yuji; Tanaka, Nobuaki; Matsubara, Yoshiyuki; Sakuma, Takahiro; Satomi, Aya; Otaki, Munenori; Ryu, Jyunnosuke; Mugishima, Hideo
When mature adipocytes are subjected to an in vitro dedifferentiation strategy referred to as ceiling culture, these mature adipocytes can revert to a more primitive phenotype and gain cell proliferative ability. We refer to these cells as dedifferentiated fat (DFAT) cells. In the present study, we examined the multilineage differentiation potential of DFAT cells. DFAT cells obtained from adipose tissues of 18 donors exhibited a fibroblast-like morphology and sustained high proliferative activity. Flow cytometric analysis revealed that DFAT cells comprised a highly homogeneous cell population compared with that of adipose-derived stem/stromal cells (ASCs), although the cell-surface antigen profile of DFAT cells was very similar to that of ASCs. DFAT cells lost expression of mature adipocytes marker genes but retained or gained expression of mesenchymal lineage-committed marker genes such as peroxisome proliferator-activated receptor gamma (PPARgamma), RUNX2, and SOX9. In vitro differentiation analysis revealed that DFAT cells could differentiate into adipocytes, chondrocytes, and osteoblasts under appropriate culture conditions. DFAT cells also formed osteoid matrix when implanted subcutaneously into nude mice. In addition, clonally expanded porcine DFAT cells showed the ability to differentiate into multiple mesenchymal cell lineages. These results indicate that DFAT cells represent a type of multipotent progenitor cell. The accessibility and ease of culture of DFAT cells support their potential application for cell-based therapies.
Strauss-Albee, Dara M; Horowitz, Amir; Parham, Peter; Blish, Catherine A
NK cells are responsible for recognizing and killing transformed, stressed, and infected cells. They recognize a set of non-Ag-specific features termed "altered self" through combinatorial signals from activating and inhibitory receptors. These NKRs are also expressed on CD4(+) and CD8(+) T cells, B cells, and monocytes, although a comprehensive inventory of NKR expression patterns across leukocyte lineages has never been performed. Using mass cytometry, we found that NKR expression patterns distinguish cell lineages in human peripheral blood. In individuals with high levels of CD57, indicative of a mature immune repertoire, NKRs are more likely to be expressed on non-NK cells, especially CD8(+) T cells. Mature NK and CD8(+) T cell populations show increased diversity of NKR surface expression patterns, but with distinct determinants: mature NK cells acquire primarily inhibitory receptors, whereas CD8(+) T cells attain a specific subset of both activating and inhibitory receptors, potentially imbuing them with a distinct functional role. Concurrently, monocytes show decreased expression of the generalized inhibitory receptor leukocyte Ig-like receptor subfamily b member 1, consistent with an increased activation threshold. Therefore, NKR expression is coordinately regulated as the immune system matures, resulting in the transfer of "altered self" recognition potential among leukocyte lineages. This likely reduces Ag specificity in the mature human immune system, and implies that vaccines and therapeutics that engage both its innate and adaptive branches may be more effective in the settings of aging and chronic infection.
Schiza, Natasa; Sargiannidou, Irene; Kagiava, Alexia; Karaiskos, Christos; Nearchou, Marianna; Kleopa, Kleopas A
Oligodendrocytes are coupled by gap junctions (GJs) formed mainly by connexin47 (Cx47) and Cx32. Recessive GJC2/Cx47 mutations cause Pelizaeus-Merzbacher-like disease, a hypomyelinating leukodystrophy, while GJB1/Cx32 mutations cause neuropathy and chronic or acute-transient encephalopathy syndromes. Cx32/Cx47 double knockout (Cx32/Cx47dKO) mice develop severe CNS demyelination beginning at 1 month of age leading to death within weeks, offering a relevant model to study disease mechanisms. In order to clarify whether the loss of oligodendrocyte connexins has cell autonomous effects, we generated transgenic mice expressing the wild-type human Cx32 under the control of the mouse proteolipid protein promoter, obtaining exogenous hCx32 expression in oligodendrocytes. By crossing these mice with Cx32KO mice, we obtained expression of hCx32 on Cx32KO background. Immunohistochemical and immunoblot analysis confirmed strong CNS expression of hCx32 specifically in oligodendrocytes and correct localization forming GJs at cell bodies and along the myelin sheath. TG(+)Cx32/Cx47dKO mice generated by further crossing with Cx47KO mice showed that transgenic expression of hCx32 rescued the severe early phenotype of CNS demyelination in Cx32/Cx47dKO mice, resulting in marked improvement of behavioral abnormalities at 1 month of age, and preventing the early mortality. Furthermore, TG(+)Cx32/Cx47dKO mice showed significant improvement of myelination compared with Cx32/Cx47dKO CNS at 1 month of age, while the inflammatory and astrogliotic changes were fully reversed. Our study confirms that loss of oligodendrocyte GJs has cell autonomous effects and that re-establishment of GJ connectivity by replacement of least one GJ protein provides correction of the leukodystrophy phenotype. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Feng Mei; S.Y.Christin Chong; Jonah R.Chan
The differentiation of and myelination by oligodendrocytes (OLs) are exquisitely regulated by a series of intrinsic and extrinsic mechanisms.As each OL can make differing numbers of myelin segments with variable lengths along similar axon tracts,myelination can be viewed as a graded process shaped by inhibitory/inductive cues during development.Myelination by OLs is a prime example of an adaptive process determined by the microenvironment and architecture of the central nervous system (CNS).In this review,we discuss how myelin formation by OLs may be controlled by the heterogeneous microenvironment of the CNS.Then we address recent findings demonstrating that neighboring OLs may compete for available axon space,and highlight our current understanding of myelin-based inhibitors of axonal regeneration that are potentially responsible for the reciprocal dialogue between OLs and determine the numbers and lengths of myelin internodes.Understanding the mechanisms that control the spatiotemporal regulation of myelinogenic potential during development may provide valuable insight into therapeutic strategies for promoting remyelination in an inhibitory microenvironment.
Mei, Feng; Christin Chong, S Y; Chan, Jonah R
The differentiation of and myelination by oligodendrocytes (OLs) are exquisitely regulated by a series of intrinsic and extrinsic mechanisms. As each OL can make differing numbers of myelin segments with variable lengths along similar axon tracts, myelination can be viewed as a graded process shaped by inhibitory/inductive cues during development. Myelination by OLs is a prime example of an adaptive process determined by the microenvironment and architecture of the central nervous system (CNS). in this review, we discuss how myelin formation by OLs may be controlled by the heterogeneous microenvironment of the CNS. Then we address recent findings demonstrating that neighboring OLs may compete for available axon space, and highlight our current understanding of myelin-based inhibitors of axonal regeneration that are potentially responsible for the reciprocal dialogue between OLs and determine the numbers and lengths of myelin internodes. Understanding the mechanisms that control the spatiotemporal regulation of myelinogenic potential during development may provide valuable insight into therapeutic strategies for promoting remyelination in an inhibitory microenvironment.
Qu, Xuebin; Guo, Rui; Zhang, Zhenzhong; Ma, Li; Wu, Xiuxiang; Luo, Mengjiao; Dong, Fuxing; Yao, Ruiqin
One of the pathological hallmarks of periventricular white matter injury is the vulnerability of pre-oligodendrocytes (preOLs) to hypoxia-ischemia (HI). There is increasing evidence that basic fibroblast growth factor (bFGF) is an important signaling molecule for neurogenesis and neuroprotection in the central nervous system. However, it is unknown whether bFGF protects preOLs from oxygen/glucose deprivation (OGD) damage in vitro and promotes remyelination in HI-induced rats. In this present study, bFGF exerted a protective effect on myelin by increasing the myelin thickness, the number of myelinated axons, and myelin basic protein expression in the HI-induced demyelinated neonatal rat corpus callosum. In vitro, bFGF ameliorated the impaired mitochondria and cell processes induced by OGD to promote the survival of isolated O4-positive preOLs. Additionally, the expression of fibroblast growth factor receptor 3 (FGFR3) was dramatically up-regulated in the preOLs after bFGF administration in vivo and in vitro. Thus, bFGF-stimulated remyelination in HI-induced rats by protecting the preOLs from hypoxic injury, and the mechanism involved may be mediated by FGFR3.
Chi Wang Ip
Full Text Available Mice overexpressing proteolipid protein (PLP develop a leukodystrophy-like disease involving cytotoxic, CD8+ T-lymphocytes. Here we show that these cytotoxic T-lymphocytes perturb retrograde axonal transport. Using fluorogold stereotactically injected into the colliculus superior, we found that PLP overexpression in oligodendrocytes led to significantly reduced retrograde axonal transport in retina ganglion cell axons. We also observed an accumulation of mitochondria in the juxtaparanodal axonal swellings, indicative for a disturbed axonal transport. PLP overexpression in the absence of T-lymphocytes rescued retrograde axonal transport defects and abolished axonal swellings. Bone marrow transfer from wildtype mice, but not from perforin- or granzyme B-deficient mutants, into lymphocyte-deficient PLP mutant mice led again to impaired axonal transport and the formation of axonal swellings, which are predominantly located at the juxtaparanodal region. This demonstrates that the adaptive immune system, including cytotoxic T-lymphocytes which release perforin and granzyme B, are necessary to perturb axonal integrity in the PLP-transgenic disease model. Based on our observations, so far not attended molecular and cellular players belonging to the immune system should be considered to understand pathogenesis in inherited myelin disorders with progressive axonal damage.
Wheeler, Natalie A.; Fuss, Babette; Knapp, Pamela E.
White matter injury has been frequently reported in HIV+ patients. Previous studies showed that HIV-1 Tat (transactivator of transcription), a viral protein that is produced and secreted by HIV-infected cells, is toxic to young, immature oligodendrocytes (OLGs). Adding Tat to the culture medium reduced the viability of immature OLGs, and the surviving OLGs exhibited reduced process networks. OLGs produce and secrete autotaxin (ATX), an ecto-enzyme containing a lysophospholipase D (lysoPLD) activity that converts lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA), a lipid signaling molecule that stimulates OLG differentiation. We hypothesized that Tat affects OLG development by interfering with the ATX-LPA signaling pathway. Our data show that Tat treatment leads to changes in the expression of OLG differentiation genes and the area of OLG process networks, both of which can be rescued by LPA. Tat-treated OLGs showed no change in LPA receptor expression but significantly decreased extracellular ATX levels and lysoPLD activity. In Tat transgenic mice, expression of Tat in vivo leads to decreased OLG ATX secretion. Furthermore, co-immunoprecipitation experiments revealed a potential physical interaction between Tat and ATX. Together, these data strongly suggest two functional implications of Tat blocking ATX’s lysoPLD activity. On one hand, it attenuates OLG differentiation, and on the other hand it interferes with the protective effects of LPA on OLG process morphology. PMID:27659560
Yeung Trevor M
Full Text Available Abstract Background Spinal cord injury is a serious and debilitating condition, affecting millions of people worldwide. Long seen as a permanent injury, recent advances in stem cell research have brought closer the possibility of repairing the spinal cord. One such approach involves injecting oligodendrocyte progenitor cells, derived from human embryonic stem cells, into the injured spinal cord in the hope that they will initiate repair. A phase I clinical trial of this therapy was started in mid 2010 and is currently underway. Discussion The theory underlying this approach is that these myelinating progenitors will phenotypically replace myelin lost during injury whilst helping to promote a repair environment in the lesion. However, the importance of demyelination in the pathogenesis of human spinal cord injury is a contentious issue and a body of literature suggests that it is only a minor factor in the overall injury process. Summary This review examines the validity of the theory underpinning the on-going clinical trial as well as analysing published data from animal models and finally discussing issues surrounding safety and purity in order to assess the potential of this approach to successfully treat acute human spinal cord injury.
Dries, Daniel R; Zhu, Yi; Brooks, Mieu M; Forero, Diego A; Adachi, Megumi; Cenik, Basar; West, James M; Han, Yu-Hong; Yu, Cong; Arbella, Jennifer; Nordin, Annelie; Adolfsson, Rolf; Del-Favero, Jurgen; Lu, Q Richard; Callaerts, Patrick; Birnbaum, Shari G; Yu, Gang
The biological underpinnings and the pathological lesions of psychiatric disorders are centuries-old questions that have yet to be understood. Recent studies suggest that schizophrenia and related disorders likely have their origins in perturbed neurodevelopment and can result from a large number of common genetic variants or multiple, individually rare genetic alterations. It is thus conceivable that key neurodevelopmental pathways underline the various genetic changes and the still unknown pathological lesions in schizophrenia. Here, we report that mice defective of the nicastrin subunit of γ-secretase in oligodendrocytes have hypomyelination in the central nervous system. These mice have altered dopamine signaling and display profound abnormal phenotypes reminiscent of schizophrenia. In addition, we identify an association of the nicastrin gene with a human schizophrenia cohort. These observations implicate γ-secretase and its mediated neurodevelopmental pathways in schizophrenia and provide support for the "myelination hypothesis" of the disease. Moreover, by showing that schizophrenia and obsessive-compulsive symptoms could be modeled in animals wherein a single genetic factor is altered, our work provides a biological basis that schizophrenia with obsessive-compulsive disorder is a distinct subtype of schizophrenia.
Full Text Available Lead (Pb poisoning has always been a serious health concern, as it permanently damages the central nervous system. Chronic Pb accumulation in the human body disturbs oligodendrocytes (OLs differentiation, resulting in dysmyelination, but the molecular mechanism remains unknown. In this study, Pb at 1 μM inhibits OLs precursor cells (OPCs differentiation via decreasing the expression of Olig 2, CNPase proteins in vitro. Moreover, Pb treatment inhibits the sodium/calcium exchanger 3 (NCX3 mRNA expression, one of the major means of calcium (Ca2+ extrusion at the plasma membrane during OPCs differentiation. Also addition of KB-R7943, NCX3 inhibitor, to simulate Pb toxicity, resulted in decreased myelin basic protein (MBP expression and cell branching. Ca2+ response trace with Pb and KB-R7943 treatment did not drop down in the same recovery time as the control, which elevated intracellular Ca2+ concentration reducing MBP expression. In contrast, over-expression of NCX3 in Pb exposed OPCs displayed significant increase MBP fluorescence signal in positive regions and CNPase expression, which recovered OPCs differentiation to counterbalance Pb toxicity. In conclusion, Pb exposure disturbs OLs differentiation via affecting the function of NCX3 by inducing intracellular calcium overload.
Hong Cui; Lijun Yang; Dezhuang Huang; Wandong Zhang; Weijuan Han; Yanqing Yao; Wenxing Jiang
Numerous studies have confirmed that oligodendrocyte transcription factor 1 (Olig-1) is vital for myelin repair. However, the effects of hypoxia and ischemia on Olig-1 expression remain unknown.In this study, Olig-1 mRNA and protein expressions were analyzed by in situ hybridization and immunohistochemistry, to determine the expression profile of Olig-1 in rat brain slices exposed to hypoxia and ischemia. Brains were obtained from 2-day-old Sprague-Dawley rats, and sections were randomly assigned to control and hypoxia/ischemia groups. Hematoxylin-eosin staining revealed karyorrhexis and karyopyknosis in cells from the hypoxia/ischemia group. Under electron microscopy, mitochondria swelling and neuropil edema were observed in the hypoxia/ischemia group. Olig-1 mRNA and protein expressions were increased at 1 day after hypoxia and ischemia treatment. These results suggest that in situ hybridization and immunohistochemistry could be used simultaneously to detect mRNA and protein expression in brain slices.
Feng, Ji-Feng; Gao, Xiao-Fei; Pu, Ying-Yan; Burnstock, Geoffrey; Xiang, Zhenghua; He, Cheng
Recruitment of oligodendrocyte precursor cells (OPCs) to the lesions is the most important event for remyelination after central nervous system (CNS) injury or in demyelinating diseases. However, the underlying molecular mechanism is not fully understood. In the present study, we found high concentrations of ATP could increase the number of migrating OPCs in vitro, while after pretreatment with oxidized ATP (a P2X7 receptor antagonist), the promotive effect was attenuated. The promotive effect of 2'(3')-O-(4-benzoylbenzoyl) adenosine 5'-triphosphate (BzATP) (a P2X7 receptor agonist) was more potent than ATP. After incubation with BzATP, the activity of Fyn, one member of the Src family of kinases, was enhanced. Moreover, the interaction between P2X7 and Fyn was identified by co-immunoprecipitation. After blocking the activity of Fyn or down-regulating the expression of Fyn, the migration of OPCs induced by BzATP was inhibited. These data indicate that P2X7 receptors/Fyn may mediate ATP-induced OPC migration under pathological conditions.
Lasrado, Lester Allan; Vatrapu, Ravi; Mukkamala, Raghava Rao
of understanding of the potential impact of (a) choice of the quantitative approach, and (b) scale of measurement on the design and assessment of the maturity model. To address these two methodological issues, we analysed a social media maturity data set and computed maturity scores using different quantitative......This paper presents results from an ongoing empirical study that seeks to understand the influence of different quantitative methods on the design and assessment of maturity models. Although there have been many academic publications on maturity models, there exists a significant lack...
Ono, Noriaki; Kronenberg, Henry M
Mesenchymal progenitors of the osteogenic lineage provide the flexibility for bone to grow, maintain its function and homeostasis. Traditionally, colony-forming-unit fibroblasts (CFU-Fs) have been regarded as surrogates for mesenchymal progenitors; however, this definition cannot address the function of these progenitors in their native setting. Transgenic murine models including lineage-tracing technologies based on the cre-lox system have proven to be useful in delineating mesenchymal progenitors in their native environment. Although heterogeneity of cell populations of interest marked by a promoter-based approach complicates overall interpretation, an emerging complexity of mesenchymal progenitors has been revealed. Current literatures suggest two distinct types of bone progenitor cells; growth-associated mesenchymal progenitors contribute to explosive growth of bone in early life, whereas bone marrow mesenchymal progenitors contribute to the much slower remodeling process and response to injury that occurs mainly in adulthood. More detailed relationships of these progenitors need to be studied through further experimentation.
at Stanford) express membrane-targeted tandem dimer Tomato (mT) fluorescent protein in all cells prior to Cre-mediated excision, and membrane...Tie-2 Cre x mT/mG excises dTomato ( red ) and switches on GFP expression in endothelial cells. A. CD31 immunostaining (cyan). B. VE-Cadherin...the smooth muscle genetic lineage marking of some but not all, vascular lining cells (see red unrecombined cells adjacent to green cells in Figure 5A
Mark E. Samuels
Full Text Available Genetic mosaics provide information about cellular lineages that is otherwise difficult to obtain, especially in humans. De novo mutations act as cell markers, allowing the tracing of developmental trajectories of all descendants of the cell in which the new mutation arises. De novo mutations may arise at any time during development but are relatively rare. They have usually been observed through medical ascertainment, when the mutation causes unusual clinical signs or symptoms. Mutational events can include aneuploidies, large chromosomal rearrangements, copy number variants, or point mutations. In this review we focus primarily on the analysis of point mutations and their utility in addressing questions of germ line versus somatic lineages. Genetic mosaics demonstrate that the germ line and soma diverge early in development, since there are many examples of combined somatic and germ line mosaicism for de novo mutations. The occurrence of simultaneous mosaicism in both the germ line and soma also shows that the germ line is not strictly clonal but arises from at least two, and possibly multiple, cells in the embryo with different ancestries. Whole genome or exome DNA sequencing technologies promise to expand the range of studies of genetic mosaics, as de novo mutations can now be identified through sequencing alone in the absence of a medical ascertainment. These technologies have been used to study mutation patterns in nuclear families and in monozygotic twins, and in animal model developmental studies, but not yet for extensive cell lineage studies in humans.
Xiao, Jun; Kang, Xuewei; Xie, Lihua; Qin, Qinbo; He, Zhoulin; Hu, Fangzhou; Zhang, Chun; Zhao, Rurong; Wang, Jun; Luo, Kaikun; Liu, Yun; Liu, Shaojun
Distant hybridization can combine together the genomes of different species, which leads to changes of the offspring in phenotypes and genotypes. In this study, we successfully establish a fertile hybrid lineage by intergeneric hybridization of female blunt snout bream (BSB, Megalobrama amblycephala) × male topmouth culter (TC, Culter alburnus) and investigate some important biological traits of this lineage including the morphological traits, chromosomal number, karyotype, DNA content, gonadal development, egg and milt yield, sperm shape and density, fertilization rate and early survival rate. The results show that: (1) the diploid and triploid hybrids coexist in F1 and only diploid hybrids are found in F2, in which the diploid hybrids of F1 and F2 possess 48 chromosomes with one chromosome set of BSB and one chromosome set of TC, and the triploid hybrids of F1 possess 72 chromosomes with two chromosome sets of BSB and one chromosome set of TC. (2) All the tested males and females of the diploid F1 and F2 hybrids have the normal gonadal development and produce mature sperm and egg, respectively, which are fertilized with each other to form F2 and F3 hybrids, respectively, and finally form a diploid hybrid lineage (F1-F3). (3) The good fertility of the F1 and F2 hybrids of female BSB × male TC potentially provides reproductive base to make the hybrid lineage propagate from one generation to another. The formation of the hybrid lineage (F1-F3) also provides an ideal model to research the reproductive rules of distant hybrid progeny.
The Zygomycete lineages mark the major transition from zoosporic life histories of the common ancestors of Fungi and the earliest diverging chytrid lineages (Chytridiomycota and Blastocladiomycota). Genome comparisons from these lineages may reveal gene content changes that reflect the transition to...
More than 98% of reported human listeriosis cases are caused by Listeria monocytogenes serotypes within lineages I and II. Serotypes within lineage III (4a and 4c) are commonly isolated from environmental and food specimens. We report the first complete genome sequence of a lineage III isolate, HCC2...
Full Text Available A history of infectious mononucleosis (IM, symptomatic primary infection with the Epstein Barr virus, is associated with the development of autoimmune diseases and increases the risk to develop multiple sclerosis. Here, we hypothesized that immune activation during IM triggers autoreactive immune responses. Antibody responses towards cellular antigens using a HEp-2 based indirect immunofluorescence assay and native myelin oligodendrocyte glycoprotein (MOG using a flow cytometry-based assay were determined in 35 patients with IM and in 23 control subjects. We detected frequent immunoglobulin M (IgM reactivity to vimentin, a major constituent of the intermediate filament family of proteins, in IM patients (27/35; 77% but rarely in control subjects (2/23; 9%. IgG autoantibodies binding to HEp-2 cells were absent in both groups. In contrast, IgG responses to native MOG, present in up to 40% of children with inflammatory demyelinating diseases of the central nervous system (CNS, were detectable in 7/35 (20% patients with IM but not in control subjects. Normalization of anti-vimentin IgM levels to increased total IgM concentrations during IM resulted in loss of significant differences for anti-vimentin IgM titers. Anti-MOG specific IgG responses were still detectable in a subset of three out of 35 patients with IM (9%, even after normalization to increased total IgG levels. Vimentin-specific IgM and MOG-specific IgG responses decreased following clinical resolution of acute IM symptoms. We conclude from our data that MOG-specific memory B cells are activated in subset of patients with IM.
Hayashi, Takahito; Ago, Kazutoshi; Nakamae, Takuma; Higo, Eri; Ogata, Mamoru
Interleukin (IL)-8 has been suggested to be a positive regulator of myelination in the central nervous system, in addition to its principal role as a chemokine for neutrophils. Immunostaining for beta-amyloid precursor protein (AβPP) is an effective tool for detecting traumatic axonal injury, although AβPP immunoreactivity can also indicate axonal injury due to hypoxic causes. In this study, we examined IL-8 and AβPP immunoreactivity in sections of corpus callosum obtained from deceased patients with blunt head injury and from equivalent control tissue. AβPP immunoreactivity was detected in injured axons, such as axonal bulbs and varicose axons, in 24 of 44 head injury cases. These AβPP immunoreactive cases had survived for more than 3h. The AβPP immunostaining pattern can be classified into two types: traumatic (Pattern 1) and non-traumatic (Pattern 2) axonal injuries, which we described previously [Hayashi et al. Int. J. Legal Med. 129 (2015) 1085-1090]. Three of 44 control cases also showed AβPP immunoreactive injured axons as Pattern 2. In contrast, IL-8 immunoreactivity was detected in 7 AβPP immunoreactive and in 2 non-AβPP immunoreactive head injury cases, but was not detected in any of the 44 control cases, including the 3 AβPP immunoreactive control cases. The IL-8 immunoreactive cases had survived from 3 to 24 days, whereas those cases who survived less than 3 days (n=29) and who survived 90 days (n=1) were not IL-8 immunoreactive. Moreover, IL-8 was detected as Pattern 1 axons only. In addition, double immunofluorescence analysis showed that IL-8 is expressed by oligodendrocytes surrounding injured axons. In conclusion, our results suggest that immunohistochemical detection of IL-8 may be useful as a complementary diagnostic marker of traumatic axonal injury.
Full Text Available In relapsing-remitting multiple sclerosis (RRMS subtype, the patient’s brain itself is capable of repairing the damage, remyelinating the axon and recovering the neurological function. Cerebrospinal fluid (CSF is in close proximity with brain parenchyma and contains a host of proteins and other molecules, which influence the cellular physiology, that may balance damage and repair of neurons and glial cells. The purpose of this study was to determine the pathophysiological mechanisms underpinning myelin repair in distinct clinical forms of MS and neuromyelitis optica (NMO patients by studying the effect of diseased CSF on glucose metabolism and ATP synthesis. A cellular model with primary cultures of oligodendrocyte progenitor cells (OPCs from rat cerebrum was employed, and cells were treated with CSF from distinct clinical forms of MS, NMO patients and neurological controls. Prior to comprehending mechanisms underlying myelin repair, we determine the best stably expressed reference genes in our experimental condition to accurately normalize our target mRNA transcripts. The GeNorm and NormFinder algorithms showed that mitochondrial ribosomal protein (Mrpl19, hypoxanthine guanine phosphoribosyl transferase (Hprt, microglobulin β2 (B2m, and transferrin receptor (Tfrc were identified as the best reference genes in OPCs treated with MS subjects and were used for normalizing gene transcripts. The main findings on microarray gene expression profiling analysis on CSF treated OPCs cells revealed a disturbed carbohydrate metabolism and ATP synthesis in MS and NMO derived CSF treated OPCs. In addition, using STRING program, we investigate whether gene–gene interaction affected the whole network in our experimental conditions. Our findings revealed downregulated expression of genes involved in carbohydrate metabolism, and that glucose metabolism impairment and reduced ATP availability for cellular damage repair clearly differentiate more benign forms
Tsiperson, Vladislav; Huang, Yangyang; Bagayogo, Issa; Song, Yeri; VonDran, Melissa W; DiCicco-Bloom, Emanuel; Dreyfus, Cheryl F
Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of growth factors that through its neurotrophic tyrosine kinase, receptor, type 2 (TrkB) receptor, increases 5-bromo-2-deoxyuridine incorporation in oligodendrocyte progenitor cells (OPCs) in culture. Roles in vivo are less well understood; however, increases in numbers of OPCs are restricted in BDNF+/- mice following cuprizone-elicited demyelination. Here, we investigate whether these blunted increases in OPCs are associated with changes in proliferation. BDNF+/+ and BDNF+/- mice were fed cuprizone-containing or control feed. To assess effects on OPC numbers, platelet-derived growth factor receptor alpha (PDGFRα)+ or NG2+ cells were counted. To monitor DNA synthesis, 5-ethynyl-2'-deoxyuridine (EdU) was injected intraperitoneally and colocalized with PDGFRα+ cells. Alternatively, proliferating cell nuclear antigen (PCNA) was colocalized with PDGFRα or NG2. Labeling indices were determined in the BDNF+/+ and BDNF+/- animals. After 4 or 5 weeks of control feed, BDNF+/- mice exhibit similar numbers of OPCs compared with BDNF+/+ animals. The labeling indices for EdU and PCNA also were not significantly different, suggesting that neither the DNA synthesis phase (S phase) nor the proliferative pool size was different between genotypes. In contrast, when mice were challenged by cuprizone for 4 or 5 weeks, increases in OPCs observed in BDNF+/+ mice were reduced in the BDNF+/- mice. This difference in elevations in cell number was accompanied by decreases in EdU labeling and PCNA labeling without changes in cell death, indicating a reduction in the DNA synthesis and the proliferative pool. Therefore, levels of BDNF influence the proliferation of OPCs resulting from a demyelinating lesion.
Full Text Available Neural stem cells (NSCs are a small population of resident cells that can grow, migrate and differentiate into neuro-glial cells in the central nervous system (CNS. Peroxisome proliferator-activated receptor gamma (PPARγ is a nuclear receptor transcription factor that regulates cell growth and differentiation. In this study we analyzed the influence of PPARγ agonists on neural stem cell growth and differentiation in culture. We found that in vitro culture of mouse NSCs in neurobasal medium with B27 in the presence of epidermal growth factor (EGF and basic fibroblast growth factor (bFGF induced their growth and expansion as neurospheres. Addition of all-trans retinoic acid (ATRA and PPARγ agonist ciglitazone or 15-Deoxy-Δ(12,14-Prostaglandin J(2 (15d-PGJ2 resulted in a dose-dependent inhibition of cell viability and proliferation of NSCs in culture. Interestingly, NSCs cultured with PPARγ agonists, but not ATRA, showed significant increase in oligodendrocyte precursor-specific O4 and NG2 reactivity with a reduction in NSC marker nestin, in 3-7 days. In vitro treatment with PPARγ agonists and ATRA also induced modest increase in the expression of neuronal β-III tubulin and astrocyte-specific GFAP in NSCs in 3-7 days. Further analyses showed that PPARγ agonists and ATRA induced significant alterations in the expression of many stemness and differentiation genes associated with neuro-glial differentiation in NSCs. These findings highlight the influence of PPARγ agonists in promoting neuro-glial differentiation of NSCs and its significance in the treatment of neurodegenerative diseases.
Bryant, M R; Marta, C B; Kim, F S; Bansal, R
Fibroblast growth factors (FGFs) and their receptors (FGFRs) initiate diverse cellular responses that contribute to the regulation of oligodendrocyte (OL) function. To understand the mechanisms by which FGFRs elicit these cellular responses, we investigated the phosphorylation of signal transduction proteins and the role of cholesterol-glycosphingolipid-enriched "lipid raft" microdomains in differentiated OLs. Surprisingly, we found that the most abundant tyrosine-phosphorylated protein in OLs was the 120-kd isoform of FGFR2 and that it was phosphorylated even in the absence of FGF2, suggesting a potential ligand-independent function for this receptor. Furthermore, FGFR2, but not FGFR1, was associated with lipid raft microdomains in OLs and myelin (but not in astrocytes). This provides the first evidence for the association of FGFR with TX-100-insoluble lipid raft fractions. FGFR2 phosphorylated the key downstream target, FRS2 in OLs. Raft disruption resulted in loss of phosphorylated FRS2 from lipid rafts, coupled with the loss of Akt but not of Mek or Erk phosphorylation. This suggests that FGFR2-FRS2 signaling in lipid rafts operates via the PI3-Kinase/Akt pathway rather than the Ras/Mek/Erk pathway, emphasizing the importance of microenvironments within the cell membrane. Also present in lipid rafts in OLs and myelin, but not in astrocytes, was a novel 52-kd isoform of FGFR2 that lacked the extracellular ligand-binding region. These results demonstrate that FGFR2 in OLs and myelin possess unique characteristics that are specific both to receptor type and to OLs and provide a novel mechanism to elicit distinct cellular responses that mediate both FGF-dependent and -independent functions.
von Feilitzen, Helena
Non‐maturing liabilities, such as savings accounts, lack both predetermined maturity and reset dates due to the fact that the depositor is free to withdraw funds at any time and that the depository institution is free to change the rate. These attributes complicate the risk management of such products and no standardized solution exists. The problem is important however since non‐maturing liabilities typically make up a considerable part of the funding of a bank. In this report different mode...
Sarnat, Harvey B.
This review surveys immunocytochemical and histochemical markers of neuronal lineage for application to tissue sections of fetal and neonatal brain. They determine maturation of individual nerve cells as the tissue progresses to mature architecture. From a developmental perspective, neuronal markers are all about timing. These diverse cellular labels may be classified in two ways: 1) time of onset of expression (early; intermediate; late); 2) labeling of subcellular structures or metabolic functions (nucleoproteins; synaptic vesicle proteins; enolases; cytoskeletal elements; calcium-binding; nucleic acids; mitochondria). Apart from these positive markers of maturation, other negative markers are expressed in primitive neuroepithelial cells and early stages of neuroblast maturation, but no longer are demonstrated after initial stages of maturation. These examinations are relevant for studies of normal neuroembryology at the cellular level. In fetal and perinatal neuropathology they provide control criteria for application to malformations of the brain, inborn metabolic disorders and acquired fetal insults in which neuroblastic maturation may be altered. Disorders, in which cells differentiate abnormally, as in tuberous sclerosis and hemimegalencephaly, pose another yet aspect of mixed cellular lineage. The measurement in living patients, especially neonates, of serum and CSF levels of enolases, chromogranins and S-100 proteins as biomarkers of brain damage may potentially be correlated with their corresponding tissue markers at autopsy in infants who do not survive. The neuropathological markers here described can be performed in ordinary hospital laboratories, not just research facilities, and offer another dimension of diagnostic precision in interpreting abnormally developed fetal and postnatal brains. PMID:23883617
Rogler, Charles E; Bebawee, Remon; Matarlo, Joe; Locker, Joseph; Pattamanuch, Nicole; Gupta, Sanjeev; Rogler, Leslie E
Recent investigations have reported many markers associated with human liver stem/progenitor cells, "oval cells," and identified "niches" in diseased livers where stem cells occur. However, there has remained a need to identify entire lineages of stem cells as they differentiate into bile ducts or hepatocytes. We have used combined immunohistochemical staining for a marker of hepatic commitment and specification (FOXA2 [Forkhead box A2]), hepatocyte maturation (Albumin and HepPar1), and features of bile ducts (CK19 [cytokeratin 19]) to identify lineages of stem cells differentiating toward the hepatocytic or bile ductular compartments of end-stage cirrhotic human liver. We identified large clusters of disorganized, FOXA2 expressing, oval cells in localized liver regions surrounded by fibrotic matrix, designated as "micro-niches." Specific FOXA2-positive cells within the micro-niches organize into primitive duct structures that support both hepatocytic and bile ductular differentiation enabling identification of entire lineages of cells forming the two types of structures. We also detected expression of hsa-miR-122 in primitive ductular reactions expected for hepatocytic differentiation and hsa-miR-23b cluster expression that drives liver cell fate decisions in cells undergoing lineage commitment. Our data establish the foundation for a mechanistic hypothesis on how stem cell lineages progress in specialized micro-niches in cirrhotic end-stage liver disease.
Semple, Bridgette D.; Blomgren, Klas; Gimlin, Kayleen; Ferriero, Donna M.; Noble-Haeusslein, Linda J.
Hypoxic-ischemic and traumatic brain injuries are leading causes of long-term mortality and disability in infants and children. Although several preclinical models using rodents of different ages have been developed, species differences in the timing of key brain maturation events can render comparisons of vulnerability and regenerative capacities difficult to interpret. Traditional models of developmental brain injury have utilized rodents at postnatal day 7–10 as being roughly equivalent to a term human infant, based historically on the measurement of post-mortem brain weights during the 1970s. Here we will examine fundamental brain development processes that occur in both rodents and humans, to delineate a comparable time course of postnatal brain development across species. We consider the timing of neurogenesis, synaptogenesis, gliogenesis, oligodendrocyte maturation and age-dependent behaviors that coincide with developmentally regulated molecular and biochemical changes. In general, while the time scale is considerably different, the sequence of key events in brain maturation is largely consistent between humans and rodents. Further, there are distinct parallels in regional vulnerability as well as functional consequences in response to brain injuries. With a focus on developmental hypoxicischemic encephalopathy and traumatic brain injury, this review offers guidelines for researchers when considering the most appropriate rodent age for the developmental stage or process of interest to approximate human brain development. PMID:23583307
Full Text Available Abstract Background Transplantation of oligodendrocyte precursor cells (OPCs is an attractive therapy for demyelinating diseases. Cyclosporin A (CsA is one of the foremost immunosuppressive agents and has widespread use in tissue and cell transplantation. However, whether CsA affects survival and differentiation of engrafted OPCs in vivo is unknown. In this study, the effect of CsA on morphological, functional and immunological aspects, as well as survival and differentiation of engrafted OPCs in injured spinal cord was explored. Results We transplanted green fluorescent protein (GFP expressed OPCs (GFP-OPCs into injured spinal cords of rats treated with or without CsA (10 mg/kg. Two weeks after cell transplantation, more GFP-positive cells were found in CsA-treated rats than that in vehicle-treated ones. However, the engrafted cells mostly differentiated into astrocytes, but not oligodendrocytes in both groups. In the CsA-treated group, a significant decrease in spinal cord lesion volume along with increase in spared myelin and neurons were found compared to the control group. Such histological improvement correlated well with an increase in behavioral recovery. Further study suggested that CsA treatment could inhibit infiltration of T cells and activation of resident microglia and/or macrophages derived from infiltrating monocytes in injured spinal cords, which contributes to the survival of engrafted OPCs and repair of spinal cord injury (SCI. Conclusions These results collectively indicate that CsA can promote the survival of engrafted OPCs in injured spinal cords, but has no effect on their differentiation. The engrafted cells mostly differentiated into astrocytes, but not oligodendrocytes. The beneficial effect of CsA on SCI and the survival of engrafted cells may be attributed to its neuroprotective effect.
Moon, Ji Hye
This dissertation aims to understand the maturational and non-maturational aspects of early bilingualism and language attrition in heritage speakers who have acquired their L1 incompletely in childhood. The study highlights the influential role of age and input dynamics in early L1 development, where the timing of reduction in L1 input and the…
Nightingale Kendra K
Full Text Available Abstract Background The bacterium Listeria monocytogenes is a saprotroph as well as an opportunistic human foodborne pathogen, which has previously been shown to consist of at least two widespread lineages (termed lineages I and II and an uncommon lineage (lineage III. While some L. monocytogenes strains show evidence for considerable diversification by homologous recombination, our understanding of the contribution of recombination to L. monocytogenes evolution is still limited. We therefore used STRUCTURE and ClonalFrame, two programs that model the effect of recombination, to make inferences about the population structure and different aspects of the recombination process in L. monocytogenes. Analyses were performed using sequences for seven loci (including the house-keeping genes gap, prs, purM and ribC, the stress response gene sigB, and the virulence genes actA and inlA for 195 L. monocytogenes isolates. Results Sequence analyses with ClonalFrame and the Sawyer's test showed that recombination is more prevalent in lineage II than lineage I and is most frequent in two house-keeping genes (ribC and purM and the two virulence genes (actA and inlA. The relative occurrence of recombination versus point mutation is about six times higher in lineage II than in lineage I, which causes a higher genetic variability in lineage II. Unlike lineage I, lineage II represents a genetically heterogeneous population with a relatively high proportion (30% average of genetic material imported from external sources. Phylograms, constructed with correcting for recombination, as well as Tajima's D data suggest that both lineages I and II have suffered a population bottleneck. Conclusion Our study shows that evolutionary lineages within a single bacterial species can differ considerably in the relative contributions of recombination to genetic diversification. Accounting for recombination in phylogenetic studies is critical, and new evolutionary models that
Drøjdahl, Nina; Fenger, Christina; Nielsen, Helle H
degeneration and lesion-induced axonal sprouting in the hippocampal dentate gyrus in TNF-transgenic mice with the response in genetically normal mice. Transectioning of the entorhino-dentate perforant path axonal projection increased hippocampal TNF mRNA expression in both types of mice, but to significantly...... larger levels in the TNF-transgenics. At 5 days after axonal transection, numbers of oligodendrocytes and myelin basic protein (MBP) mRNA expression in the denervated dentate gyrus in TNF-transgenic mice had increased to the same extent as in nontransgenic littermates. At this time, transgenics showed...
Haiying Wu; Min Hu; Dekai Yuan; Yunhui Wang; Jing Wang; Tao Li; Chuanyun Qian
A contusive model of spinal cord injury at spinal segment T8-9 was established in rats. Huantiao (GB30) and Huatuojiaji (Ex-B05) were punctured with needles, and endogenous neural stem cells were labeled with 5-bromo-2'-deoxyuridine (BrdU) and NG2. Double immunofluorescence staining showed that electroacupuncture markedly increased the numbers of BrdU+/NG2+ cells at spinal cord tissue 15 mm away from the injury center in the rostral and caudal directions. The results suggest that electroacupuncture promotes the proliferation of endogenous neural stem cells and oligodendrocytes in rats with spinal cord injury.
Gang, Lin; Yao, Yu-Chen; Liu, Ying-Fu; Li, Yi-Peng; Yang, Kai; Lu, Lei; Cheng, Yuan-Chi; Chen, Xu-Yi; Tu, Yue
We present a novel in vitro model in which to investigate the efficacy of experimental drugs for the promotion of axon regeneration in the central nervous system. We co-cultured rat hippocampal neurons and cerebral cortical oligodendrocytes, and tested the co-culture system using a Nogo-66 receptor antagonist peptide (NEP1-40), which promotes axonal growth. Primary cultured oligodendrocytes suppressed axonal growth in the rat hippocampus, but NEP1-40 stimulated axonal growth in the co-culture system. Our results confirm the validity of the neuron-oligodendrocyte co-culture system as an assay for the evaluation of drugs for axon regeneration in the central nervous system.
Steck, A.J. (Department of Neurology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland); Link, H. (Department of Neurology, Karolinska Institutet, Huddinge University Hospital, Huddinge, Sweden)
Antibodies against oligodendrocytes were determined in pairs of unconcentrated CSF serum from 12 patients with multiple sclerosis (MS) and 25 control patients including 10 with aseptic meningoencephalitis (AM), using a /sup 125/I-protein A microassay. Antibody levels in serum and in CSF did not differ between MS and controls. Calculating the antibody index equal to (CSF/serum antibodies against oligodendrocytes):(CSF/serum albumin) in analogy to the CSF IgG index, thereby compensating for influence of serum antibody concentration as well as altered blood-brain barrier, no evidence was obtained for intrathecal antibody production in the patients with MS. Those with AM had higher antibody index values, probably reflecting intrathecal synthesis. Antibodies against oligodendrocytes seem to be regular component of CSF and serum in neurological diseases; intrathecal antibody production is less frequent in MS than in AM.
Full Text Available We present a novel in vitro model in which to investigate the efficacy of experimental drugs for the promotion of axon regeneration in the central nervous system. We co-cultured rat hippocampal neurons and cerebral cortical oligodendrocytes, and tested the co-culture system using a Nogo-66 receptor antagonist peptide (NEP1-40, which promotes axonal growth. Primary cultured oligodendrocytes suppressed axonal growth in the rat hippocampus, but NEP1-40 stimulated axonal growth in the co-culture system. Our results confirm the validity of the neuron-oligodendrocyte co-culture system as an assay for the evaluation of drugs for axon regeneration in the central nervous system.
Cremers, Eline M.P.; Westers, Theresia M.; Alhan, Canan; Cali, Claudia; Visser-Wisselaar, Heleen A.; Chitu, Dana A.; van der Velden, Vincent H.J.; te Marvelde, Jeroen G.; Klein, Saskia K.; Muus, Petra; Vellenga, Edo; de Greef, Georgina E.; Legdeur, Marie-Cecile C.J.C.; Wijermans, Pierre W.; Stevens-Kroef, Marian J.P.L.; da Silva-Coelho, Pedro; Jansen, Joop H.; Ossenkoppele, Gert J.; van de Loosdrecht, Arjan A.
Flow cytometric analysis is a recommended tool in the diagnosis of myelodysplastic syndromes. Current flow cytometric approaches evaluate the (im)mature myelo-/monocytic lineage with a median sensitivity and specificity of ~71% and ~93%, respectively. We hypothesized that the addition of erythroid lineage analysis could increase the sensitivity of flow cytometry. Hereto, we validated the analysis of erythroid lineage parameters recommended by the International/European LeukemiaNet Working Group for Flow Cytometry in Myelodysplastic Syndromes, and incorporated this evaluation in currently applied flow cytometric models. One hundred and sixty-seven bone marrow aspirates were analyzed; 106 patients with myelodysplastic syndromes, and 61 cytopenic controls. There was a strong correlation between presence of erythroid aberrancies assessed by flow cytometry and the diagnosis of myelodysplastic syndromes when validating the previously described erythroid evaluation. Furthermore, addition of erythroid aberrancies to two different flow cytometric models led to an increased sensitivity in detecting myelodysplastic syndromes: from 74% to 86% for the addition to the diagnostic score designed by Ogata and colleagues, and from 69% to 80% for the addition to the integrated flow cytometric score for myelodysplastic syndromes, designed by our group. In both models the specificity was unaffected. The high sensitivity and specificity of flow cytometry in the detection of myelodysplastic syndromes illustrates the important value of flow cytometry in a standardized diagnostic approach. The trial is registered at www.trialregister.nl as NTR1825; EudraCT n.: 2008-002195-10 PMID:27658438
Huanping, Zhang; Tongming, Yin
Lineage-specific genes (LSGs) are defined as genes found in one particular taxonomic group but have no significant sequence similarity with genes from other lineages, which compose about 10%?20% of the total genes in the genome of a focal organism. LSGs were first uncovered in the yeast genome in 1996. The development of the whole genome sequencing leads to the emergence of studies on LSGs as a hot topic in comparative genomics. LSGs have been extensively studied on microbial species, lower marine organisms, plant (such as Arabidopsis thaliana, Oryza sativa, Populus), insects, primate, etc; the biological functions of LSGs are important to clarify the evolution and adaptability of a species. In this review, we summarize the progress of LSGs studies, including LSGs identification, gene characterization, origin and evolution of LSGs, biological function, and expression analysis of LSGs. In addition, we discuss the existing problems and future directions for studies in this area. Our purpose is to provide some unique insights into the researches of LSGs.
Lee, Paul; Morley, Gregory; Huang, Qian; Fischer, Avi; Seiler, Stephanie; Horner, James W.; Factor, Stephen; Vaidya, Dhananjay; Jalife, Jose; Fishman, Glenn I.
Cell loss contributes to the pathogenesis of many inherited and acquired human diseases. We have developed a system to conditionally ablate cells of any lineage and developmental stage in the mouse by regulated expression of the diphtheria toxin A (DTA) gene by using tetracycline-responsive promoters. As an example of this approach, we targeted expression of DTA to the hearts of adult mice to model structural abnormalities commonly observed in human cardiomyopathies. Induction of DTA expression resulted in cell loss, fibrosis, and chamber dilatation. As in many human cardiomyopathies, transgenic mice developed spontaneous arrhythmias in vivo, and programmed electrical stimulation of isolated-perfused transgenic hearts demonstrated a strikingly high incidence of spontaneous and inducible ventricular tachycardia. Affected mice showed marked perturbations of cardiac gap junction channel expression and localization, including a subset with disorganized epicardial activation patterns as revealed by optical action potential mapping. These studies provide important insights into mechanisms of arrhythmogenesis and suggest that conditional lineage ablation may have wide applicability for studies of disease pathogenesis.
Das, Sabyasachi; Li, Jianxu; Hirano, Masayuki; Sutoh, Yoichi; Herrin, Brantley R; Cooper, Max D
Jawless vertebrates, which occupy a unique position in chordate phylogeny, employ leucine-rich repeat (LRR)-based variable lymphocyte receptors (VLR) for antigen recognition. During the assembly of the VLR genes (VLRA, VLRB and VLRC), donor LRR-encoding sequences are copied in a step-wise manner into the incomplete germ-line genes. The assembled VLR genes are differentially expressed by discrete lymphocyte lineages: VLRA- and VLRC-producing cells are T-cell like, whereas VLRB-producing cells are B-cell like. VLRA(+) and VLRC(+) lymphocytes resemble the two principal T-cell lineages of jawed vertebrates that express the αβ or γδ T-cell receptors (TCR). Reminiscent of the interspersed nature of the TCRα/TCRδ locus in jawed vertebrates, the close proximity of the VLRA and VLRC loci facilitates sharing of donor LRR sequences during VLRA and VLRC assembly. Here we discuss the insight these findings provide into vertebrate T- and B-cell evolution, and the alternative types of anticipatory receptors they use for adaptive immunity.
Brinkmann, Melanie M; Dağ, Franziska; Hengel, Hartmut; Messerle, Martin; Kalinke, Ulrich; Čičin-Šain, Luka
Cytomegalovirus (CMV) evades the immune system in many different ways, allowing the virus to grow and its progeny to spread in the face of an adverse environment. Mounting evidence about the antiviral role of myeloid immune cells has prompted the research of CMV immune evasion mechanisms targeting these cells. Several cells of the myeloid lineage, such as monocytes, dendritic cells and macrophages, play a role in viral control, but are also permissive for CMV and are naturally infected by it. Therefore, CMV evasion of myeloid cells involves mechanisms that qualitatively differ from the evasion of non-CMV-permissive immune cells of the lymphoid lineage. The evasion of myeloid cells includes effects in cis, where the virus modulates the immune signaling pathways within the infected myeloid cell, and those in trans, where the virus affects somatic cells targeted by cytokines released from myeloid cells. This review presents an overview of CMV strategies to modulate and evade the antiviral activity of myeloid cells in cis and in trans.
Zee, Peter C; Velicer, Gregory J
Epistatic interactions can greatly impact evolutionary phenomena, particularly the process of adaptation. Here, we leverage four parallel experimentally evolved lineages to study the emergence and trajectories of epistatic interactions in the social bacterium Myxococcus xanthus. A social gene (pilA) necessary for effective group swarming on soft agar had been deleted from the common ancestor of these lineages. During selection for competitiveness at the leading edge of growing colonies, two lineages evolved qualitatively novel mechanisms for greatly increased swarming on soft agar, whereas the other two lineages evolved relatively small increases in swarming. By reintroducing pilA into different genetic backgrounds along the four lineages, we tested whether parallel lineages showed similar patterns of epistasis. In particular, we tested whether a pattern of negative epistasis between accumulating mutations and pilA previously found in the fastest lineage would be found only in the two evolved lineages with the fastest and most striking swarming phenotypes, or rather was due to common epistatic structure across all lineages arising from the generic fixation of adaptive mutations. Our analysis reveals the emergence of negative epistasis across all four independent lineages. Further, we present results showing that the observed negative epistasis is not due exclusively to evolving populations approaching a maximum phenotypic value that inherently limits positive effects of pilA reintroduction, but rather involves direct antagonistic interactions between accumulating mutations and the reintroduced social gene.
Ramanathan, Sudarshini; Reddel, Stephen W.; Henderson, Andrew; Parratt, John D.E.; Barnett, Michael; Gatt, Prudence N.; Merheb, Vera; Kumaran, Raani-Yogeeta Anusuiya; Pathmanandavel, Karrnan; Sinmaz, Nese; Ghadiri, Mahtab; Yiannikas, Con; Vucic, Steve; Stewart, Graeme; Bleasel, Andrew F.; Booth, David; Fung, Victor S.C.; Dale, Russell C.
Objective: We examined a cohort of adults with aquaporin-4 (AQP4) antibody–negative neuromyelitis optica/neuromyelitis optica spectrum disorder (NMO/NMOSD) for antibodies to myelin oligodendrocyte glycoprotein (MOG). Methods: We performed a flow cytometry cell-based assay using live human lentivirus–transduced cells expressing full-length surface MOG. Serum was tested in 23 AQP4 antibody–negative NMO/NMOSD patients with bilateral and/or recurrent optic neuritis (BON, n = 11), longitudinally extensive transverse myelitis (LETM, n = 10), and sequential BON and LETM (n = 2), as well as in patients with multiple sclerosis (MS, n = 76) and controls (n = 52). Results: MOG antibodies were detected in 9/23 AQP4 antibody–negative patients with NMO/NMOSD, compared to 1/76 patients with MS and 0/52 controls (p < 0.001). MOG antibodies were detected in 8/11 patients with BON, 0/10 patients with LETM, and 1/2 patients with sequential BON and LETM. Six of 9 MOG antibody–positive patients had a relapsing course. MOG antibody–positive patients had prominent optic disc swelling and were more likely to have a rapid response to steroid therapy and relapse on steroid cessation than MOG antibody–negative patients (p = 0.034 and p = 0.029, respectively). While 8/9 MOG antibody–positive patients had good follow-up visual acuity, one experienced sustained visual impairment, 3 had retinal nerve fiber layer thinning, and one had residual spinal disability. Conclusions: MOG antibodies have a strong association with BON and may be a useful clinical biomarker. MOG antibody–associated BON is a relapsing disorder that is frequently steroid responsive and often steroid dependent. Failure to recognize the disorder early and institute immunotherapy promptly may be associated with sustained impairment. Classification of evidence: This study provides Class II evidence that MOG antibodies are associated with AQP4 antibody–negative BON (sensitivity 69%, 95% confidence interval [CI
Full Text Available Abstract Background Serum autoantibodies against the water channel aquaporin-4 (AQP4 are important diagnostic biomarkers and pathogenic factors for neuromyelitis optica (NMO. However, AQP4-IgG are absent in 5-40% of all NMO patients and the target of the autoimmune response in these patients is unknown. Since recent studies indicate that autoimmune responses to myelin oligodendrocyte glycoprotein (MOG can induce an NMO-like disease in experimental animal models, we speculate that MOG might be an autoantigen in AQP4-IgG seronegative NMO. Although high-titer autoantibodies to human native MOG were mainly detected in a subgroup of pediatric acute disseminated encephalomyelitis (ADEM and multiple sclerosis (MS patients, their role in NMO and High-risk NMO (HR-NMO; recurrent optic neuritis-rON or longitudinally extensive transverse myelitis-LETM remains unresolved. Results We analyzed patients with definite NMO (n = 45, HR-NMO (n = 53, ADEM (n = 33, clinically isolated syndromes presenting with myelitis or optic neuritis (CIS, n = 32, MS (n = 71 and controls (n = 101; 24 other neurological diseases-OND, 27 systemic lupus erythematosus-SLE and 50 healthy subjects for serum IgG to MOG and AQP4. Furthermore, we investigated whether these antibodies can mediate complement dependent cytotoxicity (CDC. AQP4-IgG was found in patients with NMO (n = 43, 96%, HR-NMO (n = 32, 60% and in one CIS patient (3%, but was absent in ADEM, MS and controls. High-titer MOG-IgG was found in patients with ADEM (n = 14, 42%, NMO (n = 3, 7%, HR-NMO (n = 7, 13%, 5 rON and 2 LETM, CIS (n = 2, 6%, MS (n = 2, 3% and controls (n = 3, 3%, two SLE and one OND. Two of the three MOG-IgG positive NMO patients and all seven MOG-IgG positive HR-NMO patients were negative for AQP4-IgG. Thus, MOG-IgG were found in both AQP4-IgG seronegative NMO patients and seven of 21 (33% AQP4-IgG negative HR-NMO patients. Antibodies to MOG and AQP4 were predominantly of the IgG1 subtype, and were able
Tokumoto, Yasuhito; Tamaki, Shinpei; Kabe, Yasuaki; Takubo, Keiyo; Suematsu, Makoto
The adult mammalian central nervous system (CNS) contains a population of slowly dividing oligodendrocyte precursor cells (OPCs), i.e., adult OPCs, which supply new oligodendrocytes throughout the life of animal. While adult OPCs develop from rapidly dividing perinatal OPCs, the mechanisms underlying their quiescence remain unknown. Here, we show that perinatal rodent OPCs cultured with thyroid hormone (TH) under hypoxia become quiescent and acquire adult OPCs-like characteristics. The cyclin-dependent kinase inhibitor p15/INK4b plays crucial roles in the TH-dependent cell cycle deceleration in OPCs under hypoxia. Klf9 is a direct target of TH-dependent signaling. Under hypoxic conditions, hypoxia-inducible factors mediates runt-related transcription factor 1 activity to induce G1 arrest in OPCs through enhancing TH-dependent p15/INK4b expression. As adult OPCs display phenotypes of adult somatic stem cells in the CNS, the current results shed light on environmental requirements for the quiescence of adult somatic stem cells during their development from actively proliferating stem/progenitor cells.
Yao, Zong-Feng; Wang, Ying; Lin, Yu-Hong; Wu, Yan; Zhu, An-You; Wang, Rui; Shen, Lin; Xi, Jin; Qi, Qi; Jiang, Zhi-Quan; Lü, He-Zuo; Hu, Jian-Guo
Our previous study showed that Schwann cells (SCs) promote survival, proliferation and migration of co-transplanted oligodendrocyte progenitor cells (OPCs) and neurological recovery in rats with spinal cord injury (SCI). A subsequent in vitro study confirmed that SCs modulated OPC proliferation and migration by secreting platelet-derived growth factor (PDGF)-AA and fibroblast growth factor-2 (FGF)-2. We also found that PDGF-AA stimulated OPC proliferation and their differentiation into oligodendrocytes (OLs) at later stages. We therefore speculated that PDGF-AA administration can exert the same effect as SC co-transplantation in SCI repair. To test this hypothesis, in this study we investigated the effect of transplanting PDGF-AA-overexpressing OPCs in a rat model of SCI. We found that PDGF-AA overexpression in OPCs promoted their survival, proliferation, and migration and differentiation into OLs in vivo. OPCs overexpressing PDGF-AA were also associated with increased myelination and tissue repair after SCI, leading to the recovery of neurological function. These results indicate that PDGF-AA-overexpressing OPCs may be an effective treatment for SCI.
Uchida, Tsukasa; Tamaki, Yoshitaka; Ayaki, Takashi; Shodai, Akemi; Kaji, Seiji; Morimura, Toshifumi; Banno, Yoshinori; Nishitsuji, Kazuchika; Sakashita, Naomi; Maki, Takakuni; Yamashita, Hirofumi; Ito, Hidefumi; Takahashi, Ryosuke; Urushitani, Makoto
The molecular machinery responsible for cytosolic accumulation of misfolded TDP-43 in amyotrophic lateral sclerosis (ALS) remains elusive. Here we identified a cullin-2 (CUL2) RING complex as a novel ubiquitin ligase for fragmented forms of TDP-43. The von Hippel Lindau protein (VHL), a substrate binding component of the complex, preferentially recognized misfolded TDP-43 at Glu246 in RNA-recognition motif 2. Recombinant full-length TDP-43 was structurally fragile and readily cleaved, suggesting that misfolded TDP-43 is cleared by VHL/CUL2 in a step-wise manner via fragmentation. Surprisingly, excess VHL stabilized and led to inclusion formation of TDP-43, as well as mutant SOD1, at the juxtanuclear protein quality control center. Moreover, TDP-43 knockdown elevated VHL expression in cultured cells, implying an aberrant interaction between VHL and mislocalized TDP-43 in ALS. Finally, cytoplasmic inclusions especially in oligodendrocytes in ALS spinal cords were immunoreactive to both phosphorylated TDP-43 and VHL. Thus, our results suggest that an imbalance in VHL and CUL2 may underlie oligodendrocyte dysfunction in ALS, and highlight CUL2 E3 ligase emerges as a novel therapeutic potential for ALS. PMID:26751167
-like cells, whereas culturing of purified CD133+ hBM-SCs in the same media favored their differentiation into neuronal-like cells. Interestingly, coculturing of CD34+ and CD133+ hBM-SCs in the same media enhanced the differentiation into astrocyte-like cells and neuronal-like cells, in addition to oligodendrocyte-like cells. Conclusion: These results suggest that a mixture of purified CD34+ and CD133+ cells may enhance the differentiation into neuronal cell-like lineages and give broader neuronal cell lineages than when each of these cell types is cultured alone. This method opens the window for the utilization of specific populations of hBM-SCs to be delivered in a purified form for the potential treatment of neurodegenerative diseases in the future. Keywords: cell therapy, neurodegenerative disease, neurons, astrocyes, CD34+, CD133+, MACS
Jota, Marilza S; Lacerda, Daniela R; Sandoval, José R; Vieira, Pedro Paulo R; Ohasi, Dominique; Santos-Júnior, José E; Acosta, Oscar; Cuellar, Cinthia; Revollo, Susana; Paz-Y-Miño, Cesar; Fujita, Ricardo; Vallejo, Gustavo A; Schurr, Theodore G; Tarazona-Santos, Eduardo M; Pena, Sergio Dj; Ayub, Qasim; Tyler-Smith, Chris; Santos, Fabrício R
Many single-nucleotide polymorphisms (SNPs) in the non-recombining region of the human Y chromosome have been described in the last decade. High-coverage sequencing has helped to characterize new SNPs, which has in turn increased the level of detail in paternal phylogenies. However, these paternal lineages still provide insufficient information on population history and demography, especially for Native Americans. The present study aimed to identify informative paternal sublineages derived from the main founder lineage of the Americas-haplogroup Q-L54-in a sample of 1841 native South Americans. For this purpose, we used a Y-chromosomal genotyping multiplex platform and conventional genotyping methods to validate 34 new SNPs that were identified in the present study by sequencing, together with many Y-SNPs previously described in the literature. We updated the haplogroup Q phylogeny and identified two new Q-M3 and three new Q-L54*(xM3) sublineages defined by five informative SNPs, designated SA04, SA05, SA02, SA03 and SA29. Within the Q-M3, sublineage Q-SA04 was mostly found in individuals from ethnic groups belonging to the Tukanoan linguistic family in the northwest Amazon, whereas sublineage Q-SA05 was found in Peruvian and Bolivian Amazon ethnic groups. Within Q-L54*, the derived sublineages Q-SA03 and Q-SA02 were exclusively found among Coyaima individuals (Cariban linguistic family) from Colombia, while Q-SA29 was found only in Maxacali individuals (Jean linguistic family) from southeast Brazil. Furthermore, we validated the usefulness of several published SNPs among indigenous South Americans. This new Y chromosome haplogroup Q phylogeny offers an informative paternal genealogy to investigate the pre-Columbian history of South America.Journal of Human Genetics advance online publication, 31 March 2016; doi:10.1038/jhg.2016.26.
Chalfoun, Joe; Majurski, Michael; Dima, Alden; Halter, Michael; Bhadriraju, Kiran; Brady, Mary
The ability to accurately track cells and particles from images is critical to many biomedical problems. To address this, we developed Lineage Mapper, an open-source tracker for time-lapse images of biological cells, colonies, and particles. Lineage Mapper tracks objects independently of the segmentation method, detects mitosis in confluence, separates cell clumps mistakenly segmented as a single cell, provides accuracy and scalability even on terabyte-sized datasets, and creates division and/or fusion lineages. Lineage Mapper has been tested and validated on multiple biological and simulated problems. The software is available in ImageJ and Matlab at isg.nist.gov.
Supplementary radio noise advances sexual maturity in domestic pullets exposed .... non-stimulatory photoperiod in some way provides a stimulus for initiating rapid gonadal development. However, the ..... Congress, New Delhi, India. Vol II ...
Full Text Available Oligodendrocyte precursor cells (OPCs are the progenitors of myelinating oligodendrocytes in brain development and repair. Successful myelination depends on the control of adhesiveness during OPC migration and axon contact formation. The decoration of cell surface proteins with the glycan polysialic acid (polySia is a key regulatory element of OPC interactions during development and under pathological conditions. By far the major protein carrier of polySia is the neural cell adhesion molecule NCAM, but recently, polysialylation of the synaptic cell adhesion molecule SynCAM 1 has been detected in the developing mouse brain. In mice, polySia-SynCAM 1 is associated with cells expressing NG2, a marker of a heterogeneous precursor cell population, which is the primary source for oligodendrocytes in development and myelin repair but can also give rise to astrocytes and possibly neurons. It is not yet clear if polySia-SynCAM 1 is expressed by OPCs and its occurrence in humans is elusive. By generating uniform human embryonic stem cell-derived OPC cultures, we demonstrate that polySia is present on human OPCs but down-regulated during differentiation into myelin basic protein-positive oligodendrocytes. PolySia on NCAM resides on the isoforms NCAM-180 and NCAM-140, and SynCAM 1 is identified as a novel polySia acceptor in human OPCs.
Full Text Available Pelizaeus-Merzbacher disease (PMD is a form of X-linked leukodystrophy caused by mutations in the proteolipid protein 1 (PLP1 gene. Although PLP1 proteins with missense mutations have been shown to accumulate in the rough endoplasmic reticulum (ER in disease model animals and cell lines transfected with mutant PLP1 genes, the exact pathogenetic mechanism of PMD has not previously been clarified. In this study, we established induced pluripotent stem cells (iPSCs from two PMD patients carrying missense mutation and differentiated them into oligodendrocytes in vitro. In the PMD iPSC-derived oligodendrocytes, mislocalization of mutant PLP1 proteins to the ER and an association between increased susceptibility to ER stress and increased numbers of apoptotic oligodendrocytes were observed. Moreover, electron microscopic analysis demonstrated drastically reduced myelin formation accompanied by abnormal ER morphology. Thus, this study demonstrates the involvement of ER stress in pathogenic dysmyelination in the oligodendrocytes of PMD patients with the PLP1 missense mutation.
Clayton M., Jr. Carl; Albert G., Jr. Snow; Albert G. Snow
The seeds of a sugar maple tree (Acer saccharum Marsh.) do not mature at the same time every year. And different trees mature their seeds at different times. So time of year is not a reliable measure of when seeds are ripe. Better criteria are needed. In recent studies we have found that moisture content and color are the best criteria for judging when sugar maple...
Byron H. Hartman
Full Text Available Vertebrate embryogenesis gives rise to all cell types of an organism through the development of many unique lineages derived from the three primordial germ layers. The otic sensory lineage arises from the otic vesicle, a structure formed through invagination of placodal non-neural ectoderm. This developmental lineage possesses unique differentiation potential, giving rise to otic sensory cell populations including hair cells, supporting cells, and ganglion neurons of the auditory and vestibular organs. Here we present a systematic approach to identify transcriptional features that distinguish the otic sensory lineage (from early otic progenitors to otic sensory populations from other major lineages of vertebrate development. We used a microarray approach to analyze otic sensory lineage populations including microdissected otic vesicles (embryonic day 10.5 as well as isolated neonatal cochlear hair cells and supporting cells at postnatal day 3. Non-otic tissue samples including periotic tissues and whole embryos with otic regions removed were used as reference populations to evaluate otic specificity. Otic populations shared transcriptome-wide correlations in expression profiles that distinguish members of this lineage from non-otic populations. We further analyzed the microarray data using comparative and dimension reduction methods to identify individual genes that are specifically expressed in the otic sensory lineage. This analysis identified and ranked top otic sensory lineage-specific transcripts including Fbxo2, Col9a2, and Oc90, and additional novel otic lineage markers. To validate these results we performed expression analysis on select genes using immunohistochemistry and in situ hybridization. Fbxo2 showed the most striking pattern of specificity to the otic sensory lineage, including robust expression in the early otic vesicle and sustained expression in prosensory progenitors and auditory and vestibular hair cells and supporting
Butt, A M; Ibrahim, M; Gregson, N; Berry, M
We have previously demonstrated differences in the expression of carbonic anhydrase II (CAII) in oligodendrocyte units myelinating small and large diameter fibres in the anterior medullary velum (AMV) of the adult rat (each unit comprises the cell body, processes and myelin sheaths). Others have indicated that myelin composition may also vary with respect to myelin basic protein (MBP) and proteolipid protein (PLP), and the small (S)- and large (L)-isoforms of myelin associated glycoprotein (MAG). In this study, we have determined the expression of myelin proteins in oligodendrocyte unit phenotypes I-IV, which myelinate fibres ranging in diameter from 0.3-12 microns diameter in the AMV, by using double immunolabelling for Rip, which labels entire units, and MBP, PLP, myelin oligodendrocyte glycoprotein (MOG), L-MAG and S-MAG. We show differences in the expression of L- and S-MAG in units which myelinate different diameter fibres: (1) type I/II units myelinating small diameter fibres had a L-MAG+/S-MAG-/CAII+ phenotype; (2) type II/III units myelinating different diameter fibres had a L-MAG+/S-MAG+/CAII+ phenotype; (3) type III/IV units myelinated large diameter fibres had a L-MAG+/S-MAG+/CAII- phenotype. All units, irrespective of fibre diameter, expressed Rip, MBP, PLP and MOG. The results indicate that type I-IV units may be variants of a single oligodendrocyte population and that phenotypic differences are determined by the diameter of fibres within the unit. The possible significance of metabolic and biochemical differences between oligodendrocytes myelinating small and large diameter axons are discussed with reference to the pathology of demyelination.
Zhang, Ye; Sloan, Steven A; Clarke, Laura E; Caneda, Christine; Plaza, Colton A; Blumenthal, Paul D; Vogel, Hannes; Steinberg, Gary K; Edwards, Michael S B; Li, Gordon; Duncan, John A; Cheshier, Samuel H; Shuer, Lawrence M; Chang, Edward F; Grant, Gerald A; Gephart, Melanie G Hayden; Barres, Ben A
The functional and molecular similarities and distinctions between human and murine astrocytes are poorly understood. Here, we report the development of an immunopanning method to acutely purify astrocytes from fetal, juvenile, and adult human brains and to maintain these cells in serum-free cultures. We found that human astrocytes have abilities similar to those of murine astrocytes in promoting neuronal survival, inducing functional synapse formation, and engulfing synaptosomes. In contrast to existing observations in mice, we found that mature human astrocytes respond robustly to glutamate. Next, we performed RNA sequencing of healthy human astrocytes along with astrocytes from epileptic and tumor foci and compared these to human neurons, oligodendrocytes, microglia, and endothelial cells (available at http://www.brainrnaseq.org). With these profiles, we identified novel human-specific astrocyte genes and discovered a transcriptome-wide transformation between astrocyte precursor cells and mature post-mitotic astrocytes. These data represent some of the first cell-type-specific molecular profiles of the healthy and diseased human brain.
Full Text Available Recently, the Immunological Genome Project (ImmGen completed the first phase of the goal to understand the molecular circuitry underlying the immune cell lineage in mice. That milestone resulted in the creation of the most comprehensive collection of gene expression profiles in the immune cell lineage in any model organism of human disease. There is now a requisite to examine this resource using bioinformatics integration with other molecular information, with the aim of gaining deeper insights into the underlying processes that characterize this immune cell lineage. We present here a bioinformatics approach to study differential protein interaction mechanisms across the entire immune cell lineage, achieved using affinity propagation applied to a protein interaction network similarity matrix. We demonstrate that the integration of protein interaction networks with the most comprehensive database of gene expression profiles of the immune cells can be used to generate hypotheses into the underlying mechanisms governing the differentiation and the differential functional activity across the immune cell lineage. This approach may not only serve as a hypothesis engine to derive understanding of differentiation and mechanisms across the immune cell lineage, but also help identify possible immune lineage specific and common lineage mechanism in the cells protein networks.
Rodilla, Veronica; Dasti, Alessandro; Huyghe, Mathilde; Lafkas, Daniel; Laurent, Cécile; Reyal, Fabien; Fre, Silvia
The hierarchical relationships between stem cells and progenitors that guide mammary gland morphogenesis are still poorly defined. While multipotent basal stem cells have been found within the myoepithelial compartment, the in vivo lineage potential of luminal progenitors is unclear. Here we used the expression of the Notch1 receptor, previously implicated in mammary gland development and tumorigenesis, to elucidate the hierarchical organization of mammary stem/progenitor cells by lineage tracing. We found that Notch1 expression identifies multipotent stem cells in the embryonic mammary bud, which progressively restrict their lineage potential during mammary ductal morphogenesis to exclusively generate an ERαneg luminal lineage postnatally. Importantly, our results show that Notch1-labelled cells represent the alveolar progenitors that expand during pregnancy and survive multiple successive involutions. This study reveals that postnatal luminal epithelial cells derive from distinct self-sustained lineages that may represent the cells of origin of different breast cancer subtypes.
Darras, Hugo; Aron, Serge
We report a remarkable pattern of incongruence between nuclear and mitochondrial variations in a social insect, the desert ant Cataglyphis hispanica. This species reproduces by social hybridogenesis. In all populations, two distinct genetic lineages coexist; non-reproductive workers develop from hybrid crosses between the lineages, whereas reproductive offspring (males and new queens) are typically produced asexually by parthenogenesis. Genetic analyses based on nuclear markers revealed that the two lineages remain highly differentiated despite constant hybridization for worker production. Here, we show that, in contrast with nuclear DNA, mitochondrial DNA (mtDNA) does not recover the two lineages as monophyletic. Rather, mitochondrial haplotypes cluster according to their geographical origin. We argue that this cytonuclear incongruence stems from introgression of mtDNA among lineages, and review the mechanisms likely to explain this pattern under social hybridogenesis.
Full Text Available The hierarchical relationships between stem cells and progenitors that guide mammary gland morphogenesis are still poorly defined. While multipotent basal stem cells have been found within the myoepithelial compartment, the in vivo lineage potential of luminal progenitors is unclear. Here we used the expression of the Notch1 receptor, previously implicated in mammary gland development and tumorigenesis, to elucidate the hierarchical organization of mammary stem/progenitor cells by lineage tracing. We found that Notch1 expression identifies multipotent stem cells in the embryonic mammary bud, which progressively restrict their lineage potential during mammary ductal morphogenesis to exclusively generate an ERαneg luminal lineage postnatally. Importantly, our results show that Notch1-labelled cells represent the alveolar progenitors that expand during pregnancy and survive multiple successive involutions. This study reveals that postnatal luminal epithelial cells derive from distinct self-sustained lineages that may represent the cells of origin of different breast cancer subtypes.
Full Text Available Vaccinia virus (VACV has achieved unprecedented success as a live viral vaccine for smallpox which mitigated eradication of the disease. Vaccinia virus has a complex virion morphology and recent advances have been made to answer some of the key outstanding questions, in particular, the origin and biogenesis of the virion membrane, the transformation from immature virion (IV to mature virus (MV, and the role of several novel genes, which were previously uncharacterized, but have now been shown to be essential for VACV virion formation. This new knowledge will undoubtedly contribute to the rational design of safe, immunogenic vaccine candidates, or effective antivirals in the future. This review endeavors to provide an update on our current knowledge of the VACV maturation processes with a specific focus on the initiation of VACV replication through to the formation of mature virions.
Jacobsen, Freja Aksel; Hulst, Camilla; Bäckström, Thomas;
extensively studied in immune activation, roles for Arg are incompletely characterized. To investigate the role for Arg in experimental autoimmune encephalomyelitis, we studied disease development in Arg-/- mice. Methods: Arg-/- and Arg+/+ mice were generated from breeding of Arg+/- mice on the C57BL/6......Background: Inhibition of Abl kinases has an ameliorating effect on the rodent model for multiple sclerosis, experimental autoimmune encephalomyelitis, and arrests lymphocyte activation. The family of Abl kinases consists of the Abl1/Abl and Abl2/Arg tyrosine kinases. While the Abl kinase has been...... background. Mice were immunized with the myelin oligodendrocyte glycoprotein (MOG)35-55 peptide and disease development recorded. Lymphocyte phenotypes of wild type Arg+/+ and Arg-/- mice were studied by in vitro stimulation assays and flow cytometry. Results: The breeding of Arg+/+ and Arg-/- mice showed...
Chan, Chu-Fang; Kuo, Tzu-Wei; Weng, Ju-Yun; Lin, Yen-Chu; Chen, Ting-Yu; Cheng, Jen-Kun; Lien, Cheng-Chang
Glutamatergic transmission onto oligodendrocyte precursor cells (OPCs) may regulate OPC proliferation, migration and differentiation. Dendritic integration of excitatory postsynaptic potentials (EPSPs) is critical for neuronal functions, and mechanisms regulating dendritic propagation and summation of EPSPs are well understood. However, little is known about EPSP attenuation and integration in OPCs. We developed realistic OPC models for synaptic integration, based on passive membrane responses of OPCs obtained by simultaneous dual whole-cell patch-pipette recordings. Compared with neurons, OPCs have a very low value of membrane resistivity, which is largely mediated by Ba(2+)- and bupivacaine-sensitive background K(+) conductances. The very low membrane resistivity not only leads to rapid EPSP attenuation along OPC processes but also sharpens EPSPs and narrows the temporal window for EPSP summation. Thus, background K(+) conductances regulate synaptic responses and integration in OPCs, thereby affecting activity-dependent neuronal control of OPC development and function.
Didar, Tohid Fatanat; Li, Kebin; Veres, Teodor; Tabrizian, Maryam
Despite the advances made in the field of regenerative medicine, the progress in cutting-edge technologies for separating target therapeutic cells are still at early stage of development. These cells are often rare, such as stem cells or progenitor cells that their overall properties should be maintained during the separation process for their subsequent application in regenerative medicine. This work, presents separation of oligodendrocyte progenitor cells (OPCs) from rat brain primary cultures using an integrated thermoplastic elastomeric (TPE)- based multilayer microfluidic device fabricated using hot-embossing technology. OPCs are frequently used in recovery, repair and regeneration of central nervous system after injuries. Indeed, their ability to differentiate in vitro into myelinating oligodendrocytes, are extremely important for myelin repair. OPCs form 5-10% of the glial cells population. The traditional macroscale techniques for OPCs separation require pre-processing of cells and/or multiple time consuming steps with low efficiency leading very often to alteration of their properties. The proposed methodology implies to separate OPCs based on their smaller size compared to other cells from the brain tissue mixture. Using aforementioned microfluidic chip embedded with a 5 μm membrane pore size and micropumping system, a separation efficiency more than 99% was achieved. This microchip was able to operate at flow rates up to 100 μl/min, capable of separating OPCs from a confluent 75 cm(2) cell culture flask in less than 10 min, which provides us with a high-throughput and highly efficient separation expected from any cell sorting techniques.
Na Chen; Yu-Wu Jiang; Hong-Jun Hao; Ting-Ting Ban; Kai Gao; Zhong-Bin Zhang; Jing-Min Wang
Background:Vanishing white matter disease (VWM),a human autosomal recessive inherited leukoencephalopathy,is due to mutations in eukaryotic initiation factor 2B (eIF2B).eIF2B is responsible for the initiation of protein synthesis by its guanine nucleotide exchange factor (GEF) activity.Mutations ofeIF2B impair GEF activity at different degree.Previous studies implied improperly activated unfolded protein response (UPR) and endoplasmic reticulum stress (ERS) participated in the pathogenesis ofVWM.Autophagy relieves endoplasmic reticulum load by eliminating the unfolded protein.It is still unknown the effects of genotypes on the pathogenesis.In this work,UPR and autophagy flux were analyzed with different mutational types.Methods:ERS tolerance,reflected by apoptosis and cell viability,was detected in human oligodendrocyte cell line transfected with the wild type,or different mutations ofp.Arg 113His,p.Arg269* or p.Ser610-Asp613del in eIF2Bε.A representative UPR-PERK component of activating transcription factor 4 (ATF4) was measured under the basal condition and ERS induction.Autophagy was analyzed the flux in the presence of lysosomal inhibitors.Results:The degree of ERS tolerance varied in different genotypes.The truncated or deletion mutant showed prominent apoptosis cell viability declination afder ERS induction.The most seriously damaged GEF activity ofp.Arg269* group underwent spontaneous apoptosis.The truncated or deletion mutant showed elevated ATF4 under basal as well as ERS condition.Decreased expression of LC3-Ⅰ and LC3-Ⅱ in the mutants reflected an impaired autophagy flux,which was more obvious in the truncated or deletion mutants after ERS induction.Conclusions:GEF activities in different genotypes could influence the cell ERS tolerance as well as compensatory pathways of UPR and autophagy.Oligodendrocytes with truncated or deletion mutants showed less tolerable to ERS.
Hendy Mike D
Full Text Available Abstract Correction to Shavit Grievink L, Penny D, Hendy MD, Holland BR: LineageSpecificSeqgen: generating sequence data with lineage-specific variation in the proportion of variable sites. BMC Evol Biol 2008, 8(1:317.
adel abd elhaleim hagag
Background: Neuropilins are transmembrane glycoproteins that act as receptors for vascular endothelial growth factors and are involved in the process of tumor angiogenesis. Objective: The aim of this work was to study the prognostic value of neuropilin-1 (NRP-1 expression in children with B-lineage ALL. Subjects and methods: This study was conducted on fifty children with newly diagnosed B-lineage ALL who were admitted in Oncology Unit, Pediatric Department, Tanta University Hospitals in the period from August 2010 to March 2014 including 32 males and 18 females with their ages ranged from 3-17 years and mean value of 9 ± 3.5 years. Twenty healthy age and sex matched children serving as a control group was also included in this study. Patients were subjected to history taking, clinical examination and laboratory investigations including; complete blood count, serum LDH levels, bone marrow aspiration, cytochemistry, immunophenotyping and estimation of nuropilin-1 expression on blast cells by flow cytometry. Results: The present study revealed highly significant differences in NRP-1 expression between patients with B-lineage ALL and controls. The highest levels of NRP-1 expression were noted in pre-B ALL (74.04% followed by early pre-B (23.55% and lastly mature B-ALL (12.06% with significant difference between the three subtypes. NRP-1 expression was significantly associated with higher white blood cells count, bone marrow blasts percentage and serum lactate dehydrogenase levels at diagnosis and there were significantly higher levels of NRP-1 expression on BM blasts at diagnosis in patients who subsequently relapsed or died later on during the period of follow up compared to those who achieved and maintained complete remission. Also, patients with higher NRP-1 expression had significantly shorter overall survival (OS and disease free survival (DFS than patients with low NRP-1 expression. Conclusion: Our findings suggest that neuropilin-1 has bad prognostic impact in
Full Text Available Abstract Background Multiple sclerosis (MS is a chronic inflammatory disease of the central nervous system (CNS. It is associated with local activation of microglia and astroglia, infiltration of activated macrophages and T cells, active degradation of myelin and damage to axons and neurons. The proposed role for CX3CL1 (fractalkine in the control of microglia activation and leukocyte infiltration places this chemokine and its receptor CX3CR1 in a potentially strategic position to control key aspects in the pathological events that are associated with development of brain lesions in MS. In this study, we examine this hypothesis by analyzing the distribution, kinetics, regulation and cellular origin of CX3CL1 and CX3CR1 mRNA expression in the CNS of rats with an experimentally induced MS-like disease, myelin oligodendrocyte glycoprotein (MOG-induced autoimmune encephalomyelitis (EAE. Methods The expression of CX3CL1 and its receptor CX3CR1 was studied with in situ hybridization histochemical detection of their mRNA with radio labeled cRNA probes in combination with immunohistochemical staining of phenotypic cell markers. Both healthy rat brains and brains from rats with MOG EAE were analyzed. In defined lesional stages of MOG EAE, the number of CX3CR1 mRNA-expressing cells and the intensity of the in situ hybridization signal were determined by image analysis. Data were statistically evaluated by ANOVA, followed by Tukeyprimes multiple comparison test. Results Expression of CX3CL1 mRNA was present within neuronal-like cells located throughout the neuraxis of the healthy rat. Expression of CX3CL1 remained unaltered in the CNS of rats with MOG-induced EAE, with the exception of an induced expression in astrocytes within inflammatory lesions. Notably, the brain vasculature of healthy and encephalitic animals did not exhibit signs of CX3CL1 mRNA expression. The receptor, CX3CR1, was expressed by microglial cells in all regions of the healthy brain
Bruhn, Jesper Bartholin; Vogel, Birte Fonnesbech; Gram, Lone
Listeria monocytogenes can be isolated from a range of food products and may cause food-borne outbreaks or sporadic cases of listeriosis. L. monocytogenes is divided into three genetic lineages and 13 serotypes. Strains of three serotypes (1/2a, 1/2b, and 4b) are associated with most human cases...... of listeriosis. Of these, strains of serotypes 1/2b and 4b belong to lineage 1, whereas strains of serotype 1/2a and many other strains isolated from foods belong to lineage 2. L. monocytogenes is isolated from foods by selective enrichment procedures and from patients by nonselective methods. The aim......, as lineage 1 strains, which are often isolated from clinical cases of listeriosis, may be suppressed during enrichment by other L. monocytogenes lineages present in a food sample...
... 7 Agriculture 10 2010-01-01 2010-01-01 false Maturity dates. 1421.101 Section 1421.101 Agriculture... Maturity dates. (a)(1) All marketing assistance loans shall mature on demand by CCC and no later than the... filed and disbursed except, for transferred marketing assistance loan collateral. The maturity date...
Silengo, L; Altruda, F; Dotto, G P; Lacquaniti, F; Perlo, C; Turco, E; Mangiarotti, G
In vivo and in vitro experiments have shown that processing of ribosomal RNA is a late event in ribosome biogenesis. The precursor form of RNA is probably necessary to speed up the assembly of ribomal proteins. Newly formed ribosomal particles which have already entered polyribosomes differ from mature ribosomes not only in their RNA content but also in their susceptibility to unfolding in low Mg concentration and to RNase attack. Final maturation of new ribosomes is probably dependent on their functioning in protein synthesis. Thus only those ribosomes which have proven to be functional may be converted into stable cellular structures.
Cao, Li; Gibson, Jason D; Miyamoto, Shingo; Sail, Vibhavari; Verma, Rajeev; Rosenberg, Daniel W; Nelson, Craig E; Giardina, Charles
Generating lineage-committed intestinal stem cells from embryonic stem cells (ESCs) could provide a tractable experimental system for understanding intestinal differentiation pathways and may ultimately provide cells for regenerating damaged intestinal tissue. We tested a two-step differentiation procedure in which ESCs were first cultured with activin A to favor formation of definitive endoderm, and then treated with fibroblast-conditioned medium with or without Wnt3A. The definitive endoderm expressed a number of genes associated with gut-tube development through mouse embryonic day 8.5 (Sox17, Foxa2, and Gata4 expressed and Id2 silent). The intestinal stem cell marker Lgr5 gene was also activated in the endodermal cells, whereas the Msi1, Ephb2, and Dcamkl1 intestinal stem cell markers were not. Exposure of the endoderm to fibroblast-conditioned medium with Wnt3A resulted in the activation of Id2, the remaining intestinal stem cell markers and the later gut markers Cdx2, Fabp2, and Muc2. Interestingly, genes associated with distal gut-associated mesoderm (Foxf2, Hlx, and Hoxd8) were also simulated by Wnt3A. The two-step differentiation protocol generated gut bodies with crypt-like structures that included regions of Lgr5-expressing proliferating cells and regions of cell differentiation. These gut bodies also had a smooth muscle component and some underwent peristaltic movement. The ability of the definitive endoderm to differentiate into intestinal epithelium was supported by the vivo engraftment of these cells into mouse colonic mucosa. These findings demonstrate that definitive endoderm derived from ESCs can carry out intestinal cell differentiation pathways and may provide cells to restore damaged intestinal tissue.
Endele, Max; Etzrodt, Martin; Schroeder, Timm, E-mail: email@example.com
Hematopoiesis is the cumulative consequence of finely tuned signaling pathways activated through extrinsic factors, such as local niche signals and systemic hematopoietic cytokines. Whether extrinsic factors actively instruct the lineage choice of hematopoietic stem and progenitor cells or are only selectively allowing survival and proliferation of already intrinsically lineage-committed cells has been debated over decades. Recent results demonstrated that cytokines can instruct lineage choice. However, the precise function of individual cytokine-triggered signaling molecules in inducing cellular events like proliferation, lineage choice, and differentiation remains largely elusive. Signal transduction pathways activated by different cytokine receptors are highly overlapping, but support the production of distinct hematopoietic lineages. Cellular context, signaling dynamics, and the crosstalk of different signaling pathways determine the cellular response of a given extrinsic signal. New tools to manipulate and continuously quantify signaling events at the single cell level are therefore required to thoroughly interrogate how dynamic signaling networks yield a specific cellular response. - Highlights: • Recent studies provided definite proof for lineage-instructive action of cytokines. • Signaling pathways involved in hematopoietic lineage instruction remain elusive. • New tools are emerging to quantitatively study dynamic signaling networks over time.
Marcelo Paulo Hernández
Full Text Available In this paper we examine lipophilic substances, tannins, proteins, reducing carbohydrates, starch, and oxalate salts in early lineages of Asteraceae to test if they are a useful complement to classification studies. Styles of mature flowers of 44 species were processed according to plant histochemical techniques and observed by means of a light microscope. Lipophilic compounds were always present in the cuticle and cell walls, and in some species were located inside the cells. Proteins were located in the style cell walls and cell interior of most of the analyzed species. No tannins were found. In general, there is a correlation in the presence of reducing sugars and proteins. Starch granules and oxalate salts were found in the style parenchyma of a few species. Cytoplasmic content of lipophilic compounds, proteins, and reducing sugars predominates in Barnadesioideae and Nassauvieae (Mutisioideae, and histochemical similarities were found among members of Gochnatioideae
Sally K. Mak
Key success factors for neuronal differentiation are the yield of desired neuronal marker expression, reproducibility, length, and cost. Three main neuronal differentiation approaches are stromal-induced neuronal differentiation, embryoid body (EB differentiation, and direct neuronal differentiation. Here, we describe our neurodifferentiation protocol using small molecules that very efficiently promote neural induction in a 5-stage EB protocol from six induced pluripotent stem cells (iPSC lines from patients with Parkinson’s disease and controls. This protocol generates neural precursors using Dorsomorphin and SB431542 and further maturation into dopaminergic neurons by replacing sonic hedgehog with purmorphamine or smoothened agonist. The advantage of this approach is that all patient-specific iPSC lines tested in this study were successfully and consistently coaxed into the neural lineage.
Hansen, Moritz; Perner, Mirjam
Thiomicrospira species are ubiquitously found in various marine environments and appear particularly common in hydrothermal vent systems. Members of this lineage are commonly classified as sulfur-oxidizing chemolithoautotrophs. Although sequencing of Thiomicrospira crunogena's genome has revealed genes that encode enzymes for hydrogen uptake activity and for hydrogenase maturation and assembly, hydrogen uptake ability has so far not been reported for any Thiomicrospira species. We isolated a Thiomicrospira species (SP-41) from a deep sea hydrothermal vent and demonstrated that it can oxidize hydrogen. We show in vivo hydrogen consumption, hydrogen uptake activity in partially purified protein extracts and transcript abundance of hydrogenases during different growth stages. The ability of this strain to oxidize hydrogen opens up new perspectives with respect to the physiology of Thiomicrospira species that have been detected in hydrothermal vents and that have so far been exclusively associated with sulfur oxidation. PMID:25226028
Tan, Zhaoli; Chen, Keyan; Shao, Yong; Gao, Lihua; Wang, Yan; Xu, Jianming; Jin, Yang; Hu, Xianwen; Wang, Youliang
Although liver sinusoidal endothelial cells (LSECs) have long been known to contribute to liver regeneration following injury, the exact role of these cells in liver regeneration remains poorly understood. In this work, we performed lineage tracing of LSECs in mice carrying Tie2-Cre or VE-cadherin-Cre constructs to facilitate fate-mapping of LSECs in liver regeneration. Some YFP-positive LSECs were observed to convert into hepatocytes following a two-thirds partial hepatectomy (PH). Furthermore, human umbilical vein endothelial cells (HUVECs) could be triggered to convert into cells that closely resembled hepatocytes when cultured with serum from mice that underwent an extended PH. These findings suggest that mature non-hepatocyte LSECs play an essential role in mammalian liver regeneration by converting to hepatocytes. The conversion of LSECs to hepatocyte-like (iHep) cells may provide a new approach to tissue engineering.
Somatic variants can be used as lineage markers for the phylogenetic reconstruction of cancer evolution. Since somatic phylogenetics is complicated by sample heterogeneity, novel specialized tree-building methods are required for cancer phylogeny reconstruction. We present LICHeE (Lineage Inference for Cancer Heterogeneity and Evolution), a novel method that automates the phylogenetic inference of cancer progression from multiple somatic samples. LICHeE uses variant allele frequencies of somatic single nucleotide variants obtained by deep sequencing to reconstruct multi-sample cell lineage trees and infer the subclonal composition of the samples. LICHeE is open source and available at http://viq854.github.io/lichee .
Jacob, Alison S; Busby, Eloise J; Levy, Abigail D; Komm, Natasha; Clark, C Graham
Removing the requirement for cell culture has led to a substantial increase in the number of lineages of Entamoeba recognized as distinct. Surveying the range of potential host species for this parasite genus has barely been started and it is clear that additional sampling of the same host in different locations often identifies additional diversity. In this study, using small subunit ribosomal RNA gene sequencing, we identify four new lineages of Entamoeba, including the first report of Entamoeba from an elephant, and extend the host range of some previously described lineages. In addition, examination of microbiome data from a number of host animals suggests that substantial Entamoeba diversity remains to be uncovered.
Grace E.Asuelime; Yanhong Shi
The field of regenerative medicine is rapidly gaining momentum as an increasing number of reports emerge concerning the induced conversions observed in cellular fate reprogramming.While in recent years,much attention has been focused on the conversion of fate-committed somatic cells to an embryonic-like or pluripotent state,there are still many limitations associated with the applications of induced pluripotent stem cell reprogramming,including relatively low reprogramming efficiency,the times required for the reprogramming event to take place,the epigenetic instability,and the tumorigenicity associated with the pluripotent state.On the other hand,lineage reprogramming involves the conversion from one mature cell type to another without undergoing conversion to an unstable intermediate.It provides an alternative approach in regenerative medicine that has a relatively lower risk of tumorigenesis and increased efficiency within specific cellular contexts.While lineage reprogramming provides exciting potential,there is still much to be assessed before this technology is ready to be applied in a clinical setting.
Billon, Nathalie; Dani, Christian
The current epidemic of obesity and overweight has caused a surge of interest in the study of adipose tissue formation. Much progress has been made in defining the transcriptional networks controlling the terminal differentiation of adipocyte progenitors into mature adipocytes. However, the early steps of adipocyte development and the embryonic origin of this lineage have been largely disregarded until recently. In mammals, two functionally different types of adipose tissues coexist, which are both involved in energy balance but assume opposite functions. White adipose tissue (WAT) stores energy, while brown adipose tissue (BAT) is specialized in energy expenditure. WAT and BAT can be found as several depots located in various sites of the body. Individual fat depots exhibit different timing of appearance during development, as well as distinct functional properties, suggesting possible differences in their developmental origin. This hypothesis has recently been revisited through large-scale genomics studies and in vivo lineage tracing approaches, which are reviewed in this report. These studies have provided novel fundamental insights into adipocyte biology, pointing out distinct developmental origins for WAT and BAT, as well as for individual WAT depots. They suggest that the adipose tissue is composed of distinct mini-organs, exhibiting developmental and functional differences, as well as variable contribution to obesity-related metabolic diseases.
Lawrence Kohlberg's stages of moral development, when applied to theories of teaching composition, support any method or material that refers to the age and prior experience of the writer and the newness of the task the writer is attempting. Rhetorical development and maturation in the ability to write and argue persuasively are partly conceptual…
Zinner Henriksen, Helle; Andersen, Kim Normann; Medaglia, Rony
citizenpublic interaction, such as in public education. In this paper we use a revised version of the Public Sector Process Rebuilding (PPR) maturity model for mapping 200 websites of public primary schools in Denmark. Findings reveal a much less favorable picture of the digitization of the Danish public sector...
Haymes, Michael; Green, Logan
Maturity in conative development (type of motivation included in Maslow's needs hierarchy) was found to be predictive of helping behavior in middle class white male college students. The effects of safety and esteem needs were compared, and the acceptance of responsibility was also investigated. (GDC)
Coticchio, Giovanni; Dal-Canto, Mariabeatrice; Guglielmo, Maria-Cristina; Mignini-Renzini, Mario; Fadini, Rubens
Oocytes from medium-sized antral follicles have already completed their growth phase and, if released from the follicular environment and cultured in vitro, are able to resume the meiotic process and mature. However, in vitro maturation (IVM) does not entirely support all the nuclear and cytoplasmic changes that occur physiologically as an effect of the ovulatory stimulus. Regardless, oocyte IVM is widely applied for the breeding of agriculturally important species. In assisted reproduction technology, IVM has been proposed as an alternative treatment to circumvent the drawbacks of standard ovarian stimulation regimens. Initially introduced to eliminate the risks of ovarian hyperstimulation syndrome afflicting women presenting with polycystic ovaries, subsequently IVM has been suggested to represent an additional approach suitable also for normovulatory patients. So far, in children born from IVM cycles, no doubts of an increased incidence of congenital abnormalities have been raised. Many more births would be achieved if novel IVM systems, currently dominated by empiricism, could be conceived according to more physiological criteria. Recent findings shedding new light on the control of meiotic progression, the support of cumulus cells to the oocyte cellular reorganization occurring during maturation, and the modulation of the stimulus that promotes oocyte maturation downstream the mid-cycle gonadotropin signal are likely to provide crucial hints for the development of more efficient IVM systems.
Nguyen, Giang D; Gokhan, Solen; Molero, Aldrin E; Yang, Seung-Min; Kim, Byung-Ju; Skoultchi, Arthur I; Mehler, Mark F
H1 linker histone proteins are essential for the structural and functional integrity of chromatin and for the fidelity of additional epigenetic modifications. Deletion of H1c, H1d and H1e in mice leads to embryonic lethality by mid-gestation with a broad spectrum of developmental alterations. To elucidate the cellular and molecular mechanisms underlying H1 linker histone developmental functions, we analyzed embryonic stem cells (ESCs) depleted of H1c, H1d and H1e subtypes (H1-KO ESCs) by utilizing established ESC differentiation paradigms. Our study revealed that although H1-KO ESCs continued to express core pluripotency genes and the embryonic stem cell markers, alkaline phosphatase and SSEA1, they exhibited enhanced cell death during embryoid body formation and during specification of mesendoderm and neuroectoderm. In addition, we demonstrated deregulation in the developmental programs of cardiomyocyte, hepatic and pancreatic lineage elaboration. Moreover, ectopic neurogenesis and cardiomyogenesis occurred during endoderm-derived pancreatic but not hepatic differentiation. Furthermore, neural differentiation paradigms revealed selective impairments in the specification and maturation of glutamatergic and dopaminergic neurons with accelerated maturation of glial lineages. These impairments were associated with deregulation in the expression profiles of pro-neural genes in dorsal and ventral forebrain-derived neural stem cell species. Taken together, these experimental observations suggest that H1 linker histone proteins are critical for the specification, maturation and fidelity of organ-specific cellular lineages derived from the three cardinal germ layers.
Albert Basson, M.; Bommhardt, Ursula; Cole, Michael S.; Tso, J. Yun; Zamoyska, Rose
The signals that direct differentiation of T cells to the CD4 or CD8 lineages in the thymus remain poorly understood. Although it has been relatively easy to direct differentiation of CD4 single positive (CD4+) cells using combinations of antibodies and pharmacological agents that mimic receptor engagements, equivalent stimuli do not induce efficient maturation of CD8+ cells. Here we report that, irrespective of the MHC-restriction specificity of the TCR, differentiation of mature CD8+ thymocytes can be induced by ligation of CD3 polypeptides on immature thymocytes with a F(ab′)2 reagent (CD3fos-F(ab′)2). The tyrosine phosphorylation patterns stimulated by CD3fos-F(ab′)2 have been shown to resemble those delivered to mature T cells by antagonist peptides, which are known to direct positive selection of CD8+ cells, and we can show that this reagent exhibits potent antagonistic-like activity for primary T cell responses. Our results suggest a distinction in the signals that specify lineage commitment in the thymus. We present a model of thymocyte differentiation that proposes that the relative balance of signals delivered by TCR engagement and by p56lck activation is responsible for directing commitment to the CD8 or CD4 lineages. PMID:9547336
Giang D Nguyen
Full Text Available H1 linker histone proteins are essential for the structural and functional integrity of chromatin and for the fidelity of additional epigenetic modifications. Deletion of H1c, H1d and H1e in mice leads to embryonic lethality by mid-gestation with a broad spectrum of developmental alterations. To elucidate the cellular and molecular mechanisms underlying H1 linker histone developmental functions, we analyzed embryonic stem cells (ESCs depleted of H1c, H1d and H1e subtypes (H1-KO ESCs by utilizing established ESC differentiation paradigms. Our study revealed that although H1-KO ESCs continued to express core pluripotency genes and the embryonic stem cell markers, alkaline phosphatase and SSEA1, they exhibited enhanced cell death during embryoid body formation and during specification of mesendoderm and neuroectoderm. In addition, we demonstrated deregulation in the developmental programs of cardiomyocyte, hepatic and pancreatic lineage elaboration. Moreover, ectopic neurogenesis and cardiomyogenesis occurred during endoderm-derived pancreatic but not hepatic differentiation. Furthermore, neural differentiation paradigms revealed selective impairments in the specification and maturation of glutamatergic and dopaminergic neurons with accelerated maturation of glial lineages. These impairments were associated with deregulation in the expression profiles of pro-neural genes in dorsal and ventral forebrain-derived neural stem cell species. Taken together, these experimental observations suggest that H1 linker histone proteins are critical for the specification, maturation and fidelity of organ-specific cellular lineages derived from the three cardinal germ layers.
Jackson, Duncan E
Female attraction to an environmentally derived mating signal released by male orchid bees may be tightly linked to shared olfactory preferences of both sexes. A change in perfume preference may have led to divergence of two morphologically distinct lineages.
Wilm, Bettina; Muñoz-Chapuli, Ramon
The spatiotemporal expression pattern of Wt1 has been extensively studied in a number of animal models to establish its function and the developmental fate of the cells expressing this gene. In this chapter, we review the available animal models for Wt1-expressing cell lineage analysis, including direct Wt1 expression reporters and systems for permanent Wt1 lineage tracing. We describe the presently used constitutive or inducible genetic lineage tracing approaches based on the Cre/loxP system utilizing Cre recombinase expression under control of a Wt1 promoter.To make these systems accessible, we provide laboratory protocols that include dissection and processing of the tissues for immunofluorescence and histopathological analysis of the lineage-labeled Wt1-derived cells within the embryo/tissue context.
Involvement of multiple cell lineages in atherogenesis. ... PROMOTING ACCESS TO AFRICAN RESEARCH ... smooth muscle cells, fibroblasts, stem cells, pericytes, mast cells, dendritic cells, macrophages and immigrant cells usually found in ...
Full Text Available All forms of life are confronted with environmental and genetic perturbations, making phenotypic robustness an important characteristic of life. Although development has long been viewed as a key component of phenotypic robustness, the underlying mechanism is unclear. Here we report that the determinative developmental cell lineages of two protostomes and one deuterostome are structured such that the resulting cellular compositions of the organisms are only modestly affected by cell deaths. Several features of the cell lineages, including their shallowness, topology, early ontogenic appearances of rare cells, and non-clonality of most cell types, underlie the robustness. Simple simulations of cell lineage evolution demonstrate the possibility that the observed robustness arose as an adaptation in the face of random cell deaths in development. These results reveal general organizing principles of determinative developmental cell lineages and a conceptually new mechanism of phenotypic robustness, both of which have important implications for development and evolution.
Flores Carlos; Larruga José M; González Ana M; Maca-Meyer Nicole; Cabrera Vicente M
Abstract Background The phylogeographic distribution of human mitochondrial DNA variations allows a genetic approach to the study of modern Homo sapiens dispersals throughout the world from a female perspective. As a new contribution to this study we have phylogenetically analysed complete mitochondrial DNA(mtDNA) sequences from 42 human lineages, representing major clades with known geographic assignation. Results We show the relative relationships among the 42 lineages and present more accu...
Illingworth, Robert S; Hölzenspies, Jurriaan J; Roske, Fabian V
Mouse embryonic stem cells (ESCs), like the blastocyst from which they are derived, contain precursors of the epiblast (Epi) and primitive endoderm (PrEn) lineages. While transient in vivo, these precursor populations readily interconvert in vitro. We show that altered transcription is the driver...... polycomb with dynamic changes in transcription and stalled lineage commitment, allowing cells to explore alternative choices prior to a definitive decision....
Riyahi Zaniani, Fatemeh; Moghim, Sharareh; Mirhendi, Hossein; Ghasemian Safaei, Hajieh; Fazeli, Hossein; Salehi, Mahshid; Nasr Esfahani, Bahram
In this study, we aimed to identify the genetic lineages of Mycobacterium tuberculosis isolates in Isfahan via the mycobacterial interspersed repetitive-unit-variable number tandem repeat typing method based on 15 loci. Forty-nine M. tuberculosis isolates were collected between 2013 and 2015 from Tuberculosis patients in Mollahadi Sabzevari Tuberculosis Center in Isfahan. All isolates were typed by 15-locus MIRU-VNTR typing. The highest percentage of isolates, 44.89 % (22/49), belonged to the Euro-American lineage, while the frequencies of the East-African-Indian, East-Asian, and Indo-Oceanic lineages were 28.57 % (14/49), 24.4 % (12/49), and 2.04 % (1/49), respectively. Among the 22 isolates of the Euro-American lineage, those belonging to the NEW-1 sub-lineage were most prevalent (24.4 %). Approximately, the same proportion of isolates belonging to the Delhi/CAS, Beijing, and NEW-1 sub-lineages were identified in Iranian and Afghan immigrant patients. The Delhi/CAS and Beijing sub-lineage isolates were prevalent among patients who had been previously treated for TB. Results showed that all of the 49 MIRU-VNTR patterns were unique and the clustering rate of the 15-locus MIRU-VNTR was 0.0 (minimum recent transmission). The results of this study show that the lineages of M. tuberculosis isolates in Isfahan are similar to those reported in the Eastern Mediterranean region (indicative of the epidemiological relationship between the countries in the region). The low clustering rate in our results reveals that transmission of tuberculosis in Isfahan is, in most cases, a reactivation of previous tuberculosis infection and the role of recently transmitted disease is minor.
Full Text Available Research has been done within the South African information technology (IT industry over the last decade with regard to project management maturity (PMM and the impact it has on delivering information systems (IS projects successfully. The research was done to determine whether IS PMM per knowledge area has improved over the last decade. It investigates if there is a correlation between maturity levels and project success. Four independent surveys over the last decade focused on IS PMM and the longitudinal analysis provides a benchmark for whether IS PMM has increased or not. This article focuses on whether certain knowledge areas are more of a problem within the IT industry and to determine what the overall IS PMM is. The longitudinal analysis indicates trends and highlights areas of concern. It indicates that most IT companies are still operating at level 3 and that risk and procurement management are the knowledge areas of concern. A comparative analysis indicates that there is no difference between South African and international maturity levels. The results provide a South African perspective of IS PMM. It highlights that risk management is still a knowledge area that is neglected and that emphasis must be placed on managing risk within IT projects.
Palinauskas, Vaidas; Žiegytė, Rita; Iezhova, Tatjana A; Ilgūnas, Mikas; Bernotienė, Rasa; Valkiūnas, Gediminas
Plasmodium elongatum causes severe avian malaria and is distributed worldwide. This parasite is of particular importance due to its ability to develop and cause lethal malaria not only in natural hosts, but also in non-adapted endemic birds such as the brown kiwi and different species of penguins. Information on vectors of this infection is available but is contradictory. PCR-based analysis indicated the possible existence of a cluster of closely related P. elongatum lineages which might differ in their ability to develop in certain mosquitoes and birds. This experimental study provides information about molecular and morphological characterisation of a virulent P. elongatum strain (lineage pERIRUB01) isolated from a naturally infected European robin, Erithacus rubecula. Phylogenetic analysis based on partial cytochrome b gene sequences showed that this parasite lineage is closely related to P. elongatum (lineage pGRW6). Blood stages of both parasite lineages are indistinguishable, indicating that they belong to the same species. Both pathogens develop in experimentally infected canaries, Serinus canaria, causing death of the hosts. In both these lineages, trophozoites and erythrocytic meronts develop in polychromatic erythrocytes and erythroblasts, gametocytes parasitize mature erythrocytes, exoerythrocytic stages develop in cells of the erythrocytic series in bone marrow and are occasionally reported in spleen and liver. Massive infestation of bone marrow cells is the main reason for bird mortality. We report here on syncytium-like remnants of tissue meronts, which slip out of the bone marrow into the peripheral circulation, providing evidence that the syncytia can be a template for PCR amplification. This finding contributes to better understanding positive PCR amplifications in birds when parasitemia is invisible and improved diagnostics of abortive haemosporidian infections. Sporogony of P. elongatum (pERIRUB01) completes the cycle and sporozoites develop in
Full Text Available This paper presents a design of a Green ICT maturity model that is aimed at maturity assessment of a Green ICT capability in SMEs that figure as users of ICT services. Based on a literature review and internet search, six maturity models in the Green ICT area were detected and further analysed. Since these maturity models do not suit maturity assessment in non-ICT SMEs, a new Green ICT maturity model for SMEs was developed. This paper introduces the process of model development, description of the resulted model and evaluation of the model.
Ishizuka, Isabel E; Chea, Sylvestre; Gudjonson, Herman; Constantinides, Michael G; Dinner, Aaron R; Bendelac, Albert; Golub, Rachel
The precise lineage relationship between innate lymphoid cells (ILCs) and lymphoid tissue-inducer (LTi) cells is poorly understood. Using single-cell multiplex transcriptional analysis of 100 lymphoid genes and single-cell cultures of fetal liver precursor cells, we identified the common proximal precursor to these lineages and found that its bifurcation was marked by differential induction of the transcription factors PLZF and TCF1. Acquisition of individual effector programs specific to the ILC subsets ILC1, ILC2 and ILC3 was initiated later, at the common ILC precursor stage, by transient expression of mixed ILC1, ILC2 and ILC3 transcriptional patterns, whereas, in contrast, the development of LTi cells did not go through multilineage priming. Our findings provide insight into the divergent mechanisms of the differentiation of the ILC lineage and LTi cell lineage and establish a high-resolution 'blueprint' of their development.
Bourikas, Dimitris; Mir, Anis; Walmsley, Adrian Robert
LINGO-1 is a potent negative regulator of oligodendrocyte differentiation and hence may play a pivotal restrictive role during remyelination in demyelinating diseases such as multiple sclerosis. However, little is known as to which stages of oligodendrocyte differentiation are inhibited by LINGO-1, which domains of the protein are involved and whether accessory proteins are required. Here, we show that LINGO-1 expression in the human oligodendroglial cell line MO3.13 inhibited process extension and this was reversed by an anti-LINGO-1 antibody or the antagonist LINGO-1-Fc. LINGO-1 expression was also found to inhibit myelin basic protein transcription in the rat oligodendroglial cell line CG4. Both of these inhibitory actions of LINGO-1 were abrogated by deletion of the entire ectodomain or cytoplasmic domains but, surprisingly, were unaffected by deletion of the leucine-rich repeats (LRRs). As in neurons, LINGO-1 physically associated with endogenous p75(NTR) in MO3.13 cells and, correspondingly, its inhibition of process extension was reversed by antagonists of p75(NTR). Thus, LINGO-1 inhibits multiple aspects of oligodendrocyte differentiation independently of the LRRs via a process that requires p75(NTR) signalling.
Zhang, Haiqing; Sekhari, Aicha; Ouzrout, Yacine; Bouras, Abdelaziz
Part 8: Change Management and Maturity; International audience; Companies adopt PLM maturity models to evaluate PLM implementation and recognize relative positions in PLM selection to better harness PLM benefits. However, the majority traditional PLM maturity models are relative time-consuming and energy-consuming. This work focuses on proposing a fuzzy extended PCMA (PLM Components Maturity Assessment) maturity model to brightly evaluate the gradual process of PLM maturity accompaniment with...
Woma, T Y; Adombi, C M; Yu, D; Qasim, A M M; Sabi, A A; Maurice, N A; Olaiya, O D; Loitsch, A; Bailey, D; Shamaki, D; Dundon, W G; Quan, M
Peste-des-petits-ruminants (PPR), a major small ruminant transboundary animal disease, is endemic in Nigeria. Strains of the causal agent, peste-des-petits-ruminants virus (PPRV), have been differentiated into four genetically distinct lineages based on the partial sequence of the virus nucleoprotein (N) or fusion (F) genes. Peste-des-petits-ruminants virus strains that were identified initially in Africa were grouped into lineages I, II and III and viruses from Asia were classified as lineage IV and referred to as the Asian lineage. Many recent reports indicate that the Asian lineage is now also present in Africa. With this in mind, this study was conducted to reassess the epidemiology of PPRV in Nigeria. A total of 140 clinical samples from 16 sheep and 63 goats with symptoms suggestive of PPR were collected from different states of Nigeria during a four-year period (2010-2013). They were analysed by the amplification of fragments of the N gene. Results for 33 (42%) animals were positive. The phylogenetic analysis of the N gene sequences with those available in GenBank showed that viruses that were detected belong to both lineage II and IV. Based on an analysis of the N gene sequences, the lineage IV isolates grouped into two clades, one being predominant in the north-eastern part of the country and the other found primarily in the southern regions of the country. This study reports the presence of PPRV Asian lineage IV in Nigeria for the first time. © 2016 Blackwell Verlag GmbH.
Full Text Available Mariam Arain, Maliha Haque, Lina Johal, Puja Mathur, Wynand Nel, Afsha Rais, Ranbir Sandhu, Sushil Sharma Saint James School of Medicine, Kralendijk, Bonaire, The Netherlands Abstract: Adolescence is the developmental epoch during which children become adults – intellectually, physically, hormonally, and socially. Adolescence is a tumultuous time, full of changes and transformations. The pubertal transition to adulthood involves both gonadal and behavioral maturation. Magnetic resonance imaging studies have discovered that myelinogenesis, required for proper insulation and efficient neurocybernetics, continues from childhood and the brain's region-specific neurocircuitry remains structurally and functionally vulnerable to impulsive sex, food, and sleep habits. The maturation of the adolescent brain is also influenced by heredity, environment, and sex hormones (estrogen, progesterone, and testosterone, which play a crucial role in myelination. Furthermore, glutamatergic neurotransmission predominates, whereas gamma-aminobutyric acid neurotransmission remains under construction, and this might be responsible for immature and impulsive behavior and neurobehavioral excitement during adolescent life. The adolescent population is highly vulnerable to driving under the influence of alcohol and social maladjustments due to an immature limbic system and prefrontal cortex. Synaptic plasticity and the release of neurotransmitters may also be influenced by environmental neurotoxins and drugs of abuse including cigarettes, caffeine, and alcohol during adolescence. Adolescents may become involved with offensive crimes, irresponsible behavior, unprotected sex, juvenile courts, or even prison. According to a report by the Centers for Disease Control and Prevention, the major cause of death among the teenage population is due to injury and violence related to sex and substance abuse. Prenatal neglect, cigarette smoking, and alcohol consumption may also
Guédria, Wided; Naudet, Yannick; Chen, David
Historically, progress occurs when entities communicate, share information and together create something that no one individually could do alone. Moving beyond people to machines and systems, interoperability is becoming a key factor of success in all domains. In particular, interoperability has become a challenge for enterprises, to exploit market opportunities, to meet their own objectives of cooperation or simply to survive in a growing competitive world where the networked enterprise is becoming a standard. Within this context, many research works have been conducted over the past few years and enterprise interoperability has become an important area of research, ensuring the competitiveness and growth of European enterprises. Among others, enterprises have to control their interoperability strategy and enhance their ability to interoperate. This is the purpose of the interoperability assessment. Assessing interoperability maturity allows a company to know its strengths and weaknesses in terms of interoperability with its current and potential partners, and to prioritise actions for improvement. The objective of this paper is to define a maturity model for enterprise interoperability that takes into account existing maturity models while extending the coverage of the interoperability domain. The assessment methodology is also presented. Both are demonstrated with a real case study.
Wu, Joy Y; Aarnisalo, Piia; Bastepe, Murat; Sinha, Partha; Fulzele, Keertik; Selig, Martin K; Chen, Min; Poulton, Ingrid J; Purton, Louise E; Sims, Natalie A; Weinstein, Lee S; Kronenberg, Henry M
The heterotrimeric G protein subunit Gsα stimulates cAMP-dependent signaling downstream of G protein-coupled receptors. In this study, we set out to determine the role of Gsα signaling in cells of the early osteoblast lineage in vivo by conditionally deleting Gsα from osterix-expressing cells. This led to severe osteoporosis with fractures at birth, a phenotype that was found to be the consequence of impaired bone formation rather than increased resorption. Osteoblast number was markedly decreased and osteogenic differentiation was accelerated, resulting in the formation of woven bone. Rapid differentiation of mature osteoblasts into matrix-embedded osteocytes likely contributed to depletion of the osteoblast pool. In addition, the number of committed osteoblast progenitors was diminished in both bone marrow stromal cells (BMSCs) and calvarial cells of mutant mice. In the absence of Gsα, expression of sclerostin and dickkopf1 (Dkk1), inhibitors of canonical Wnt signaling, was markedly increased; this was accompanied by reduced Wnt signaling in the osteoblast lineage. In summary, we have shown that Gsα regulates bone formation by at least two distinct mechanisms: facilitating the commitment of mesenchymal progenitors to the osteoblast lineage in association with enhanced Wnt signaling; and restraining the differentiation of committed osteoblasts to enable production of bone of optimal mass, quality, and strength.
Chen, Ying, E-mail: firstname.lastname@example.org [Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, 333 Bostwick NE, Grand Rapids, MI 49503 (United States); Wang, Kai; Chandramouli, Gadisetti V.R. [Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, 333 Bostwick NE, Grand Rapids, MI 49503 (United States); Knott, Jason G. [Developmental Epigenetics Laboratory, Department of Animal Science, Michigan State University (United States); Leach, Richard, E-mail: Richard.email@example.com [Department of Obstetrics, Gynecology and Reproductive Biology, Michigan State University, 333 Bostwick NE, Grand Rapids, MI 49503 (United States); Department of Obstetrics, Gynecology and Women’s Health, Spectrum Health Medical Group (United States)
Highlights: •Epithelial-like phenotype of trophoblast lineage cells derived from human iPS cells. •Trophoblast lineage cells derived from human iPS cells exhibit trophoblast function. •Trophoblasts from iPS cells provides a proof-of-concept in regenerative medicine. -- Abstract: Background: During implantation, the blastocyst trophectoderm attaches to the endometrial epithelium and continues to differentiate into all trophoblast subtypes, which are the major components of a placenta. Aberrant trophoblast proliferation and differentiation are associated with placental diseases. However, due to ethical and practical issues, there is almost no available cell or tissue source to study the molecular mechanism of human trophoblast differentiation, which further becomes a barrier to the study of the pathogenesis of trophoblast-associated diseases of pregnancy. In this study, our goal was to generate a proof-of-concept model for deriving trophoblast lineage cells from induced pluripotency stem (iPS) cells from human fibroblasts. In future studies the generation of trophoblast lineage cells from iPS cells established from patient’s placenta will be extremely useful for studying the pathogenesis of individual trophoblast-associated diseases and for drug testing. Methods and results: Combining iPS cell technology with BMP4 induction, we derived trophoblast lineage cells from human iPS cells. The gene expression profile of these trophoblast lineage cells was distinct from fibroblasts and iPS cells. These cells expressed markers of human trophoblasts. Furthermore, when these cells were differentiated they exhibited invasive capacity and placental hormone secretive capacity, suggesting extravillous trophoblasts and syncytiotrophoblasts. Conclusion: Trophoblast lineage cells can be successfully derived from human iPS cells, which provide a proof-of-concept tool to recapitulate pathogenesis of patient placental trophoblasts in vitro.
Full Text Available Co-circulation of two influenza B virus lineages, B/Yamagata and B/Victoria, has been recognized since the late 1980s. The assessment of the prevalent lineage and the group of viruses in circulation is of importance in order to decide on the vaccine composition and evaluate its efficacy. The molecular characterization of influenza B viruses in circulation has been the aim of this study; this was approached by identifying and locating nucleotide substitutions in the influenza B virus hemagglutinin (HA and neuraminidase (NA, specific for the lineage and/or clade. By the alignment of 3456 sequences from the influenza GISAID EpiFlu database, a high number of lineage- and group-specific nucleotide positions have been observed in the HA gene, but not in the NA gene. Additionally, an RT-PCR method has been developed, applicable directly to clinical specimens, which amplifies a short HA region that includes a group of unique molecular signatures. Twenty eight influenza B virus-positive respiratory specimens, collected in Tuscany in the seasons 2012–2013 and 2013–2014, were analyzed. The results revealed two clearly distinguishable patterns: one, more frequent, was characterized by all of the nucleotide changes associated with the B/Yamagata lineage (in most cases of Group 2, whereas the other exhibited all of the changes associated with the B/Victoria lineage. It can be concluded that the analysis of this short HA sequence can permit a rapid, highly sensitive determination of influenza B virus lineages and clades.
Lynn, R C; Feng, Y; Schutsky, K; Poussin, M; Kalota, A; Dimitrov, D S; Powell, D J
Acute myeloid leukemia (AML) is an aggressive malignancy, and development of new treatments to prolong remissions is warranted. Chimeric antigen receptor (CAR) T-cell therapies appear promising but on-target, off-tumor recognition of antigen in healthy tissues remains a concern. Here we isolated a high-affinity (HA) folate receptor beta (FRβ)-specific single-chain variable fragment (2.48 nm KD) for optimization of FRβ-redirected CAR T-cell therapy for AML. T cells stably expressing the HA-FRβ CAR exhibited greatly enhanced antitumor activity against FRβ(+) AML in vitro and in vivo compared with a low-affinity FRβ CAR (54.3 nm KD). Using the HA-FRβ immunoglobulin G, FRβ expression was detectable in myeloid-lineage hematopoietic cells; however, expression in CD34(+) hematopoietic stem cells (HSCs) was nearly undetectable. Accordingly, HA-FRβ CAR T cells lysed mature CD14(+) monocytes, while HSC colony formation was unaffected. Because of the potential for elimination of mature myeloid lineage, mRNA CAR electroporation for transient CAR expression was evaluated. mRNA-electroporated HA-FRβ CAR T cells retained effective antitumor activity in vitro and in vivo. Together, our results highlight the importance of antibody affinity in target protein detection and CAR development and suggest that transient delivery of potent HA-FRβ CAR T cells is highly effective against AML and reduces the risk for long-term myeloid toxicity.
Mucida, Daniel; Husain, Mohammad Mushtaq; Muroi, Sawako; van Wijk, Femke; Shinnakasu, Ryo; Naoe, Yoshinori; Reis, Bernardo Sgarbi; Huang, Yujun; Lambolez, Florence; Docherty, Michael; Attinger, Antoine; Shui, Jr-Wen; Kim, Gisen; Lena, Christopher J.; Sakaguchi, Shinya; Miyamoto, Chizuko; Wang, Peng; Atarashi, Koji; Park, Yunji; Nakayama, Toshinori; Honda, Kenya; Ellmeier, Wilfried; Kronenberg, Mitchell; Taniuchi, Ichiro; Cheroutre, Hilde
TCRαβ thymocytes differentiate to either CD8αβ cytotoxic T lymphocytes or CD4+ T helper cells. This functional dichotomy is controlled by key transcription factors, including the T helper master regulator, ThPOK, which suppresses the cytolytic program in MHC class II-restricted CD4+ thymocytes. ThPOK continues to repress CD8-lineage genes in mature CD4+ T cells, even as they differentiate to T helper effector subsets. Here we show that the T helper-fate was not fixed and that mature antigen-stimulated CD4+ T cells could terminate Thpok expression and reactivate CD8-lineage genes. This unexpected plasticity resulted in the post-thymic termination of the T helper-program and the functional differentiation of distinct MHC class II-restricted CD4+ cytotoxic T lymphocytes. PMID:23334788
Lecca, Davide; Marangon, Davide; Coppolino, Giusy T.; Méndez, Aida Menéndez; Finardi, Annamaria; Costa, Gloria Dalla; Martinelli, Vittorio; Furlan, Roberto; Abbracchio, Maria P.
In the mature central nervous system (CNS), oligodendrocytes provide support and insulation to axons thanks to the production of a myelin sheath. During their maturation to myelinating cells, oligodendroglial precursors (OPCs) follow a very precise differentiation program, which is finely orchestrated by transcription factors, epigenetic factors and microRNAs (miRNAs), a class of small non-coding RNAs involved in post-transcriptional regulation. Any alterations in this program can potentially contribute to dysregulated myelination, impaired remyelination and neurodegenerative conditions, as it happens in multiple sclerosis (MS). Here, we identify miR-125a-3p, a developmentally regulated miRNA, as a new actor of oligodendroglial maturation, that, in the mammalian CNS regulates the expression of myelin genes by simultaneously acting on several of its already validated targets. In cultured OPCs, over-expression of miR-125a-3p by mimic treatment impairs while its inhibition with an antago-miR stimulates oligodendroglial maturation. Moreover, we show that miR-125a-3p levels are abnormally high in the cerebrospinal fluid of MS patients bearing active demyelinating lesions, suggesting that its pathological upregulation may contribute to MS development, at least in part by blockade of OPC differentiation leading to impaired repair of demyelinated lesions. PMID:27698367
Full Text Available Cell transplantation to treat retinal degenerative diseases represents an option for the replacement of lost photoreceptor cells. In vitro expandable cells isolated from the developing mammalian retina have been suggested as a potential source for the generation of high numbers of donor photoreceptors. In this study we used standardized culture conditions based on the presence of the mitogens FGF-2 and EGF to generate high numbers of cells in vitro from the developing mouse retina. These presumptive 'retinal stem cells' ('RSCs' can be propagated as monolayer cultures over multiple passages, express markers of undifferentiated neural cells, and generate neuronal and glial cell types upon withdrawal of mitogens in vitro or following transplantation into the adult mouse retina. The proportion of neuronal differentiation can be significantly increased by stepwise removal of mitogens and inhibition of the notch signaling pathway. However, 'RSCs', by contrast to their primary counterparts in vivo, i.e. retinal progenitor cells, loose the expression of retina-specific progenitor markers like Rax and Chx10 after passaging and fail to differentiate into photoreceptors both in vitro or after intraretinal transplantation. Notably, 'RSCs' can be induced to differentiate into myelinating oligodendrocytes, a cell type not generated by primary retinal progenitor cells. Based on these findings we conclude that 'RSCs' expanded in high concentrations of FGF-2 and EGF loose their retinal identity and acquire features of in vitro expandable neural stem-like cells making them an inappropriate cell source for strategies aimed at replacing photoreceptor cells in the degenerated retina.
Czekaj, Magdalena; Haas, Jochen; Gebhardt, Marlen; Müller-Reichert, Thomas; Humphries, Peter; Farrar, Jane; Bartsch, Udo; Ader, Marius
Cell transplantation to treat retinal degenerative diseases represents an option for the replacement of lost photoreceptor cells. In vitro expandable cells isolated from the developing mammalian retina have been suggested as a potential source for the generation of high numbers of donor photoreceptors. In this study we used standardized culture conditions based on the presence of the mitogens FGF-2 and EGF to generate high numbers of cells in vitro from the developing mouse retina. These presumptive 'retinal stem cells' ('RSCs') can be propagated as monolayer cultures over multiple passages, express markers of undifferentiated neural cells, and generate neuronal and glial cell types upon withdrawal of mitogens in vitro or following transplantation into the adult mouse retina. The proportion of neuronal differentiation can be significantly increased by stepwise removal of mitogens and inhibition of the notch signaling pathway. However, 'RSCs', by contrast to their primary counterparts in vivo, i.e. retinal progenitor cells, loose the expression of retina-specific progenitor markers like Rax and Chx10 after passaging and fail to differentiate into photoreceptors both in vitro or after intraretinal transplantation. Notably, 'RSCs' can be induced to differentiate into myelinating oligodendrocytes, a cell type not generated by primary retinal progenitor cells. Based on these findings we conclude that 'RSCs' expanded in high concentrations of FGF-2 and EGF loose their retinal identity and acquire features of in vitro expandable neural stem-like cells making them an inappropriate cell source for strategies aimed at replacing photoreceptor cells in the degenerated retina.
Zhang, Cheng; Zhang, Guanghao; Rong, Wei; Wang, Aihua; Wu, Changzhe; Huo, Xiaolin
Demyelination is part of the cascading secondary injury after the primary insult and contributes to the loss of function after spinal cord injury (SCI). Oligodendrocyte precursor cells (OPCs) are the main remyelinating cells in the central nervous system (CNS). We explored whether oscillating field stimulation (OFS) could efficiently promote OPC differentiation and improve remyelination after SCI. SD rats with SCI induced by the Allen method were randomly divided into two groups, the SCI+OFS group and SCI group. The former group received active stimulator units and the latter group received sham (inoperative) stimulator units. Additionally, rats that only received laminectomy were referred as the sham group. The electric field intensity was 600 μV/mm, and the polarity was alternated every 15 minutes. The results showed that the SCI+OFS rats had significantly less demyelination and better locomotor function recovery after 12-weeks treatment. The OFS treatment significantly increased the number of Gal C-positive OPCs after 2-weeks treatment. Furthermore, these rats had higher protein expression of oligodendroglial transcription factors Olig2 and NKx2.2. These findings suggest OFS can promote locomotor recovery and remyelination in SCI rats and this effect may be related to the improved differentiation of OPCs in the spinal cord.
Full Text Available Adult mammalian brain can be plastic after injury and disease. Therefore, boosting endogenous repair mechanisms would be a useful therapeutic approach for neurological disorders. Isoxazole-9 (Isx-9 has been reported to enhance neurogenesis from neural stem/progenitor cells (NSPCs. However, the effects of Isx-9 on other types of progenitor/precursor cells remain mostly unknown. In this study, we investigated the effects of Isx-9 on the three major populations of progenitor/precursor cells in brain: NSPCs, oligodendrocyte precursor cells (OPCs, and endothelial progenitor cells (EPCs. Cultured primary NSPCs, OPCs, or EPCs were treated with various concentrations of Isx-9 (6.25, 12.5, 25, 50 μM, and their cell numbers were counted in a blinded manner. Isx-9 slightly increased the number of NSPCs and effectively induced neuronal differentiation of NSPCs. However, Isx-9 significantly decreased OPC number in a concentration-dependent manner, suggesting cytotoxicity. Isx-9 did not affect EPC cell number. But in a matrigel assay of angiogenesis, Isx-9 significantly inhibited tube formation in outgrowth endothelial cells derived from EPCs. This potential anti-tube-formation effect of Isx-9 was confirmed in a brain endothelial cell line. Taken together, our data suggest that mechanisms and targets for promoting stem/progenitor cells in the central nervous system may significantly differ between cell types.
Yurdun Kuyucu; Ozgul Tap
Normal female fertility depends on normally occuring oogenesis and maturation progress. Oogenesis and folliculogenesis are different progresses but occure in a harmony and at the same time. Oogenesis includes the events that take place matur ovum produced from primordial germ cells. Although folliculogenesis includes the stages primordial, primary, secondary, matur (Graaf) follicules in the influece of gonadotropines and local growth factors. During oocyte maturation meiosis is distrupted til...
Lasrado, Lester; Vatrapu, Ravi; Andersen, Kim Normann
Maturity Model research in IS has been criticized for the lack of theoretical grounding, methodological rigor, empirical validations, and ignorance of multiple and non-linear paths to maturity. To address these criticisms, this paper proposes a novel set-theoretical approach to maturity models ch...
Full Text Available Fundamental aspects of embryonic and post-natal development, including maintenance of the mammalian female germline, are largely unknown. Here we employ a retrospective, phylogenetic-based method for reconstructing cell lineage trees utilizing somatic mutations accumulated in microsatellites, to study female germline dynamics in mice. Reconstructed cell lineage trees can be used to estimate lineage relationships between different cell types, as well as cell depth (number of cell divisions since the zygote. We show that, in the reconstructed mouse cell lineage trees, oocytes form clusters that are separate from hematopoietic and mesenchymal stem cells, both in young and old mice, indicating that these populations belong to distinct lineages. Furthermore, while cumulus cells sampled from different ovarian follicles are distinctly clustered on the reconstructed trees, oocytes from the left and right ovaries are not, suggesting a mixing of their progenitor pools. We also observed an increase in oocyte depth with mouse age, which can be explained either by depth-guided selection of oocytes for ovulation or by post-natal renewal. Overall, our study sheds light on substantial novel aspects of female germline preservation and development.
Reizel, Yitzhak; Itzkovitz, Shalev; Adar, Rivka; Elbaz, Judith; Jinich, Adrian; Chapal-Ilani, Noa; Maruvka, Yosef E; Nevo, Nava; Marx, Zipora; Horovitz, Inna; Wasserstrom, Adam; Mayo, Avi; Shur, Irena; Benayahu, Dafna; Skorecki, Karl; Segal, Eran; Dekel, Nava; Shapiro, Ehud
Fundamental aspects of embryonic and post-natal development, including maintenance of the mammalian female germline, are largely unknown. Here we employ a retrospective, phylogenetic-based method for reconstructing cell lineage trees utilizing somatic mutations accumulated in microsatellites, to study female germline dynamics in mice. Reconstructed cell lineage trees can be used to estimate lineage relationships between different cell types, as well as cell depth (number of cell divisions since the zygote). We show that, in the reconstructed mouse cell lineage trees, oocytes form clusters that are separate from hematopoietic and mesenchymal stem cells, both in young and old mice, indicating that these populations belong to distinct lineages. Furthermore, while cumulus cells sampled from different ovarian follicles are distinctly clustered on the reconstructed trees, oocytes from the left and right ovaries are not, suggesting a mixing of their progenitor pools. We also observed an increase in oocyte depth with mouse age, which can be explained either by depth-guided selection of oocytes for ovulation or by post-natal renewal. Overall, our study sheds light on substantial novel aspects of female germline preservation and development.
Ruth E Timme
Full Text Available The tremendous diversity of land plants all descended from a single charophyte green alga that colonized the land somewhere between 430 and 470 million years ago. Six orders of charophyte green algae, in addition to embryophytes, comprise the Streptophyta s.l. Previous studies have focused on reconstructing the phylogeny of organisms tied to this key colonization event, but wildly conflicting results have sparked a contentious debate over which lineage gave rise to land plants. The dominant view has been that 'stoneworts,' or Charales, are the sister lineage, but an alternative hypothesis supports the Zygnematales (often referred to as "pond scum" as the sister lineage. In this paper, we provide a well-supported, 160-nuclear-gene phylogenomic analysis supporting the Zygnematales as the closest living relative to land plants. Our study makes two key contributions to the field: 1 the use of an unbiased method to collect a large set of orthologs from deeply diverging species and 2 the use of these data in determining the sister lineage to land plants. We anticipate this updated phylogeny not only will hugely impact lesson plans in introductory biology courses, but also will provide a solid phylogenetic tree for future green-lineage research, whether it be related to plants or green algae.
Full Text Available Hemiascomycete yeasts cover an evolutionary span comparable to that of the entire phylum of chordates. Since this group currently contains the largest number of complete genome sequences it presents unique opportunities to understand the evolution of genome organization in eukaryotes. We inferred rates of genome instability on all branches of a phylogenetic tree for 11 species and calculated species-specific rates of genome rearrangements. We characterized all inversion events that occurred within synteny blocks between six representatives of the different lineages. We show that the rates of macro- and microrearrangements of gene order are correlated within individual lineages but are highly variable across different lineages. The most unstable genomes correspond to the pathogenic yeasts Candida albicans and Candida glabrata. Chromosomal maps have been intensively shuffled by numerous interchromosomal rearrangements, even between species that have retained a very high physical fraction of their genomes within small synteny blocks. Despite this intensive reshuffling of gene positions, essential genes, which cluster in low recombination regions in the genome of Saccharomyces cerevisiae, tend to remain syntenic during evolution. This work reveals that the high plasticity of eukaryotic genomes results from rearrangement rates that vary between lineages but also at different evolutionary times of a given lineage.
Brady, S. T.; Witt, A. S.; Kirkpatrick, L. L.; de Waegh, S. M.; Readhead, C.; Tu, P. H.; Lee, V. M.
Although traditional roles ascribed to myelinating glial cells are structural and supportive, the importance of compact myelin for proper functioning of the nervous system can be inferred from mutations in myelin proteins and neuropathologies associated with loss of myelin. Myelinating Schwann cells are known to affect local properties of peripheral axons (de Waegh et al., 1992), but little is known about effects of oligodendrocytes on CNS axons. The shiverer mutant mouse has a deletion in the myelin basic protein gene that eliminates compact myelin in the CNS. In shiverer mice, both local axonal features like phosphorylation of cytoskeletal proteins and neuronal perikaryon functions like cytoskeletal gene expression are altered. This leads to changes in the organization and composition of the axonal cytoskeleton in shiverer unmyelinated axons relative to age-matched wild-type myelinated fibers, although connectivity and patterns of neuronal activity are comparable. Remarkably, transgenic shiverer mice with thin myelin sheaths display an intermediate phenotype indicating that CNS neurons are sensitive to myelin sheath thickness. These results indicate that formation of a normal compact myelin sheath is required for normal maturation of the neuronal cytoskeleton in large CNS neurons.
Rassman, William R; Pak, Jae P; Kim, Jino
Hairlines change shape with age, starting at birth. A good head of hair is frequently present some time after ages 3 to 5 years. The look of childhood has its corresponding hairline, and, as the child grows and develops into adulthood, facial morphology migrate changes from a childlike look to a more mature look. This article discusses the dynamics of hairline evolution and the phenotypic variations of the front and side hairlines in men and women. A modeling system is introduced that provides a common language to define the various anatomic points of the full range of hairlines.
Francavilla, S; Bellocci, M; Martini, M; Bruno, B; Moscardelli, S; Fabbrini, A; Properzi, G
The ultrastructural aspects of the germinal epithelium of 10 infertile men affected by maturative arrest of spermatogenesis were studied. We noted an increased number of malformed germinal cells. Marginal nuclear vescicles were present in spermatogonia of patients affected by spermatogonial arrest. The few spermatid present in the germinal epithelium of the patients affected by a spermatidic arrest presented changes of the nuclear condensation, the acrosome, and the tail. The Sertoli cells presented an immature aspect of the nucleus and changes of the "mantle". A possible correlation between the Sertoli cells changes and the altered spermatogenesis was proposed.
Underhill, Gary K.; Carlson, Ronald A.; Clendinning, William A.; Erdos, Jozsef; Gault, John; Hall, James W.; Jones, Robert L.; Michael, Herbert K.; Powell, Paul H.; Riemann, Carl F.; Rios-Castellon, Lorenzo; Shepherd, Burchard P.; Wilson, John S.
All of the work reported in the preceding chapters was performed in order to assess the technical, economic, and energetic feasibility of proceeding with more detailed studies of the geopressured geothermal resource. The preliminary conceptual design and costing activities represented the prime activity for component by component review of the maturity of the technology available for resource utilization facilities. The economics and energetics studies focussed attentions on the areas of major capital and energy investment; these results comprise a useful guide for focussing design in order to reduce initial and operations and maintenance costs and/or investment. The following presents a discussion of the primary technical problems identified.
Erica A. Swenson; Amanda E. Rosenberger; Philip J. Howell
Fish maturity status, sex ratio, and age and size at first maturity are important parameters in population assessments and life history studies. In most empirical studies of these variables, fish are sacrificed and dissected to obtain data. However, maturity status and the sex of mature individuals can be determined by inserting an endoscope through a small incision in...
Lasrado, Lester Allan; Vatrapu, Ravi; Andersen, Kim Normann
literature reveals that researchers have primarily focused on developing new maturity models pertaining to domain-specific problems and/or new enterprise technologies. We find rampant re-use of the design structure of widely adopted models such as Nolan’s Stage of Growth Model, Crosby’s Grid, and Capability...... of maturity models. Specifically, it explores maturity models literature in IS and standard guidelines, if any to develop maturity models, challenges identified and solutions proposed. Our systematic literature review of IS publications revealed over hundred and fifty articles on maturity models. Extant...
Full Text Available Adipose tissues have striking plasticity, highlighted by childhood and adult obesity. Using adipose lineage analyses, smooth muscle actin (SMA-mural cell-fate mapping, and conditional PPARγ deletion to block adipocyte differentiation, we find two phases of adipocyte generation that emanate from two independent adipose progenitor compartments: developmental and adult. These two compartments are sequentially required for organ formation and maintenance. Although both developmental and adult progenitors are specified during the developmental period and express PPARγ, they have distinct microanatomical, functional, morphogenetic, and molecular profiles. Furthermore, the two compartments derive from different lineages; whereas adult adipose progenitors fate-map from an SMA+ mural lineage, developmental progenitors do not. Remarkably, the adult progenitor compartment appears to be specified earlier than the developmental cells and then enters the already developmentally formed adipose depots. Thus, two distinct cell compartments control adipose organ development and organ homeostasis, which may provide a discrete therapeutic target for childhood and adult obesity.
Schupp James M
Full Text Available Abstract Background The global pattern of distribution of 1033 B. anthracis isolates has previously been defined by a set of 12 conserved canonical single nucleotide polymorphisms (canSNP. These studies reinforced the presence of three major lineages and 12 sub-lineages and sub-groups of this anthrax-causing pathogen. Isolates that form the A lineage (unlike the B and C lineages have become widely dispersed throughout the world and form the basis for the geographical disposition of "modern" anthrax. An archival collection of 191 different B. anthracis isolates from China provides a glimpse into the possible role of Chinese trade and commerce in the spread of certain sub-lineages of this pathogen. Canonical single nucleotide polymorphism (canSNP and multiple locus VNTR analysis (MLVA typing has been used to examine this archival collection of isolates. Results The canSNP study indicates that there are 5 different sub-lineages/sub-groups in China out of 12 previously described world-wide canSNP genotypes. Three of these canSNP genotypes were only found in the western-most province of China, Xinjiang. These genotypes were A.Br.008/009, a sub-group that is spread across most of Europe and Asia; A.Br.Aust 94, a sub-lineage that is present in Europe and India, and A.Br.Vollum, a lineage that is also present in Europe. The remaining two canSNP genotypes are spread across the whole of China and belong to sub-group A.Br.001/002 and the A.Br.Ames sub-lineage, two closely related genotypes. MLVA typing adds resolution to the isolates in each canSNP genotype and diversity indices for the A.Br.008/009 and A.Br.001/002 sub-groups suggest that these represent older and established clades in China. Conclusion B. anthracis isolates were recovered from three canSNP sub-groups (A.Br.008/009, A.Br.Aust94, and A.Br.Vollum in the western most portion of the large Chinese province of Xinjiang. The city of Kashi in this province appears to have served as a crossroads
Buckleton, J.S.; Krawczak, M.; Weir, B.S.
Mitochondrial DNA (mtDNA) and the non-recombining portion of the Y chromosome are inherited matrilinealy and patrilinealy, respectively, and without recombination. Collectively they are termed ‘lineage markers’. Lineage markers may be used in forensic testing of an item, such as a hair from a crime scene, against a hypothesised source, or in relationship testing. An estimate of the evidential weight of a match is usually provided by a count of the occurrence in some database of the mtDNA or Y-STR haplotype under consideration. When the factual statement of a count in the database is applied to a case, issues of relevance of the database and sampling uncertainty may arise. In this paper, we re-examine the issues of sampling uncertainty, the relevance of the database, and the combination of autosomal and lineage marker evidence. We also review the recent developments by C.H. Brenner. PMID:21397888
Full Text Available Abstract Background Recent findings indicate that evolutionary breaks in the genome are not randomly distributed, and that certain regions, so-called fragile regions, are predisposed to breakages. Previous approaches to the study of genomic fragility have examined the distribution of breaks, as well as the coincidence of breaks with segmental duplications and repeats, within a single species. In contrast, we investigate whether this regional fragility is an inherent genomic characteristic and is thus conserved over multiple independent lineages. Results We do this by quantifying the extent to which certain genomic regions are disrupted repeatedly in independent lineages. Our investigation, based on Human, Chimp, Mouse, Rat, Dog and Chicken, suggests that the propensity of a chromosomal region to break is significantly correlated among independent lineages, even when covariates are considered. Furthermore, the fragile regions are enriched for segmental duplications. Conclusion Based on a novel methodology, our work provides additional support for the existence of fragile regions.
Kwiatek, Olivier; Ali, Yahia Hassan; Saeed, Intisar Kamil; Khalafalla, Abdelmelik Ibrahim; Mohamed, Osama Ishag; Obeida, Ali Abu; Abdelrahman, Magdi Badawi; Osman, Halima Mohamed; Taha, Khalid Mohamed; Abbas, Zakia; El Harrak, Mehdi; Lhor, Youssef; Diallo, Adama; Lancelot, Renaud; Albina, Emmanuel; Libeau, Genevieve
Interest in peste des petits ruminants virus (PPRV) has been stimulated by recent changes in its host and geographic distribution. For this study, biological specimens were collected from camels, sheep, and goats clinically suspected of having PPRV infection in Sudan during 2000-2009 and from sheep soon after the first reported outbreaks in Morocco in 2008. Reverse transcription PCR analysis confirmed the wide distribution of PPRV throughout Sudan and spread of the virus in Morocco. Molecular typing of 32 samples positive for PPRV provided strong evidence of the introduction and broad spread of Asian lineage IV. This lineage was defined further by 2 subclusters; one consisted of camel and goat isolates and some of the sheep isolates, while the other contained only sheep isolates, a finding with suggests a genetic bias according to the host. This study provides evidence of the recent spread of PPRV lineage IV in Africa.
Full Text Available Since we still know very little about stem cells in their natural environment, it is useful to explore their dynamics through modelling and simulation, as well as experimentally. Most models of stem cell systems are based on deterministic differential equations that ignore the natural heterogeneity of stem cell populations. This is not appropriate at the level of individual cells and niches, when randomness is more likely to affect dynamics. In this paper, we introduce a fast stochastic method for simulating a metapopulation of stem cell niche lineages, that is, many sub-populations that together form a heterogeneous metapopulation, over time. By selecting the common limiting timestep, our method ensures that the entire metapopulation is simulated synchronously. This is important, as it allows us to introduce interactions between separate niche lineages, which would otherwise be impossible. We expand our method to enable the coupling of many lineages into niche groups, where differentiated cells are pooled within each niche group. Using this method, we explore the dynamics of the haematopoietic system from a demand control system perspective. We find that coupling together niche lineages allows the organism to regulate blood cell numbers as closely as possible to the homeostatic optimum. Furthermore, coupled lineages respond better than uncoupled ones to random perturbations, here the loss of some myeloid cells. This could imply that it is advantageous for an organism to connect together its niche lineages into groups. Our results suggest that a potential fruitful empirical direction will be to understand how stem cell descendants communicate with the niche and how cancer may arise as a result of a failure of such communication.
de Leeuw, Christiaan A.; Knegt, Bram; Maas, Diede L.; de Voogd, Nicole J.; Abdunnur; Suyatna, Iwan; Peijnenburg, Katja T.C.A.
Marine lakes, with populations in landlocked seawater and clearly delineated contours, have the potential to provide a unique model to study early stages of evolution in coastal marine taxa. Here we ask whether populations of the mussel Brachidontes from marine lakes in Berau, East Kalimantan (Indonesia) are isolated from each other and from the coastal mangrove systems. We analyzed sequence data of one mitochondrial marker (Cytochrome Oxidase I (COI)), and two nuclear markers (18S and 28S). In addition, we examined shell shape using a geometric morphometric approach. The Indonesian populations of Brachidontes spp. harbored four deeply diverged lineages (14–75% COI corrected net sequence divergence), two of which correspond to previously recorded lineages from marine lakes in Palau, 1,900 km away. These four lineages also showed significant differences in shell shape and constitute a species complex of at least four undescribed species. Each lake harbored a different lineage despite the fact that the lakes are separated from each other by only 2–6 km, while the two mangrove populations, at 20 km distance from each other, harbored the same lineage and shared haplotypes. Marine lakes thus represent isolated habitats. As each lake contained unique within lineage diversity (0.1–0.2%), we suggest that this may have resulted from in situdivergence due to isolation of founder populations after the formation of the lakes (6,000–12,000 years before present). Combined effects of stochastic processes, local adaptation and increased evolutionary rates could produce high levels of differentiation in small populations such as in marine lake environments. Such short-term isolation at small spatial scales may be an important contributing factor to the high marine biodiversity that is found in the Indo-Australian Archipelago. PMID:27761314
Leontine E. Becking
Full Text Available Marine lakes, with populations in landlocked seawater and clearly delineated contours, have the potential to provide a unique model to study early stages of evolution in coastal marine taxa. Here we ask whether populations of the mussel Brachidontes from marine lakes in Berau, East Kalimantan (Indonesia are isolated from each other and from the coastal mangrove systems. We analyzed sequence data of one mitochondrial marker (Cytochrome Oxidase I (COI, and two nuclear markers (18S and 28S. In addition, we examined shell shape using a geometric morphometric approach. The Indonesian populations of Brachidontes spp. harbored four deeply diverged lineages (14–75% COI corrected net sequence divergence, two of which correspond to previously recorded lineages from marine lakes in Palau, 1,900 km away. These four lineages also showed significant differences in shell shape and constitute a species complex of at least four undescribed species. Each lake harbored a different lineage despite the fact that the lakes are separated from each other by only 2–6 km, while the two mangrove populations, at 20 km distance from each other, harbored the same lineage and shared haplotypes. Marine lakes thus represent isolated habitats. As each lake contained unique within lineage diversity (0.1–0.2%, we suggest that this may have resulted from in situdivergence due to isolation of founder populations after the formation of the lakes (6,000–12,000 years before present. Combined effects of stochastic processes, local adaptation and increased evolutionary rates could produce high levels of differentiation in small populations such as in marine lake environments. Such short-term isolation at small spatial scales may be an important contributing factor to the high marine biodiversity that is found in the Indo-Australian Archipelago.
Oligodendroglial cell proliferation arising in an ovarian mature cystic teratoma. Clinicopathological, inmunohistochemical, and ultrastructural study of a case that may represent an oligodendroglioma.
Serrano-Arévalo, Mónica Lizzette; Lino-Silva, Leonardo Saúl; Domínguez Malagón, Hugo Ricardo
Ovarian mature cystic teratoma (OMCT) is an ovarian benign neoplasm with excellent prognosis presenting components of the three germinal layers. However, transformation into a malignant neoplasm is a rare event (so-called somatic transformation). In most of the cases, the malignant component expresses as epidermoid carcinoma, but occasionally central nervous system tumors occur. Some of the previously reported tumors are astrocytoma, glioblastoma, and ependymoma. Somatic transformation of OMCT into an oligodendroglioma is exceptional. We report a 19-year-old female with a left OMCT with an area of oligonedroglial cells proliferation characterized by immunohistochemical studies with positivity for GFAP and S100, with a low Ki67 index (5%). Additionally, electron microscopy revealed oligodendrocytes with parallel bundles of cytoplasmic intermediate filaments, confirming the oligodendroglial nature of the proliferation. The patient was treated only with left oophorectomy, and three and half years after surgery, there is no evidence of disease.
Lasrado, Lester Allan; Vatrapu, Ravi; Andersen, Kim Normann
Maturity models are widespread in IS research and in particular, IT practitioner communities. However, theoretically sound, methodologically rigorous and empirically validated maturity models are quite rare. This literature review paper focuses on the challenges faced during the development...... literature reveals that researchers have primarily focused on developing new maturity models pertaining to domain-specific problems and/or new enterprise technologies. We find rampant re-use of the design structure of widely adopted models such as Nolan’s Stage of Growth Model, Crosby’s Grid, and Capability...... Maturity Model (CMM). Only recently have there been some research efforts to standardize maturity model development. We also identify three dominant views of maturity models and provide guidelines for various approaches of constructing maturity models with a standard vocabulary. We finally propose using...
Full Text Available Normal female fertility depends on normally occuring oogenesis and maturation progress. Oogenesis and folliculogenesis are different progresses but occure in a harmony and at the same time. Oogenesis includes the events that take place matur ovum produced from primordial germ cells. Although folliculogenesis includes the stages primordial, primary, secondary, matur (Graaf follicules in the influece of gonadotropines and local growth factors. During oocyte maturation meiosis is distrupted till the puberty. Under LH influence it starts again and first meiosis completes before ovulation. Oocyte maturation can be regarded as the process of coming metaphase II from prophase I of oocyte at the puberty and can be studied as nuclear and cytoplasmic maturation. Meiosis is completed when fertilization occures and zygot is formed. In this article oogenesis, folliculogenesis and oocyte maturation process are summerized with related studies and reiews are revised. [Archives Medical Review Journal 2009; 18(4.000: 227-240
An Alzheimer's Disease-Relevant Presenilin-1 Mutation Augments Amyloid-Beta-Induced Oligodendrocyte Dysfunction%An Alzheimer's Disease-Relevant Presenilin-1Mutation Augments Amyloid-Beta-Induced Oligodendrocyte Dysfunction
MAYA K. DESAI; BRENDAN J. GUERCIO; WADE C. NARROW; AND WILLIAM J. BOWERS
研究表明,家族性阿尔茨海默病(FAD)患者处于无症状或临床前阶段时,脑白质即出现病理改变.此种改变在髓鞘破坏及阿尔茨海默病(AD)病理生理中的作用有待进一步研究阐明.笔者前期研究证实,三重转基因AD小鼠(人淀粉前体蛋白基因的Swedish突变,早老素-1 M146V (PS1M146V)敲入突变及tauP301L突变)表现出类似FAD患者的髓鞘破坏,Aβ1-42促进了白质病变.本研究离体实验证实,PS1M146V变异导致小鼠少突胶质前体细胞在分化过程中易出现类似Aβ1-42诱导的变化.PS1M146V的表达损伤少突胶质前体细胞的功能并影响髓鞘碱性蛋白的分布,暴露于Aβ1-42加重此影响.由PS1M146V及 Aβ1-42导致的髓鞘破坏及髓鞘碱性蛋白在亚细胞结构中的误定位可被TWS119(糖原合成激酶(GSK)-3β抑制剂)抑制,提示GSK-3β激酶活动在此病理过程中有重要作用.综上所述,本研究有助于增加对AD早期无症状阶段,由PS1M146V及 Aβ1-42导致少突胶质细胞功能异常及髓鞘损伤的机制的理解,并提供了针对少突胶质细胞预防AD相关白质病变的新的治疗靶点.%White matter pathology has been documented in the brains of familial Alzheimer's disease (FAD)-afflicted individuals during presymptomatic and preclinical stages of AD. How these defects in myelination integrity arise and what roles they may play in AD pathophysiology have yet to be fully elucidated. We previously demonstrated that triple-transgenic AD (3xTg-AD) mice, which harbor the human amyloid precursor Swedish mutation, presenilin-1 M146V (PS1M146V) knock-in mutation, and tauP301L mutation, exhibit myelin abnormalities analogous to FAD patients and that Aβ1-42 contributes to these white matter deficits. Herein, we demonstrate that the PS1M146V mutation predisposes mouse oligodendrocyte precursor (mOP) cells to Aβ1 42-induced alterations in cell differentiation in vitro. Furthermore, PS1M146V expression compromised m
Balboni, Andrea; De Lorenzo Dandola, Giorgia; Scagliarini, Alessandra; Prosperi, Santino; Battilani, Mara
This study describes the sequence analysis of the H gene of 7 Canine distemper virus (CDV) strains identified in dogs in Italy between years 2002-2012. The phylogenetic analysis showed that the CDV strains belonged to 2 clusters: 6 viruses were identified as Arctic-like lineage and 1 as Europe 1 lineage. These data show a considerable prevalence of Arctic-like-CDVs in the analysed dogs. The dogs and the 3 viruses more recently identified showed 4 distinctive amino acid mutations compared to all other Arctic CDVs.
Oshio, S; Ozaki, S; Ohkawa, I; Tajima, T; Kaneko, S; Mohri, H
The effect of Mecobalamin (alpha-(5,6-dimethyl benzimidazolyl)-Co-methyl-cobamide: Me-B 12) on sperm production in the oligozoospermic mice experimentally induced by the treatment with adriamycin (0.3 mg/kg, three times a week for 5 weeks) was evaluated quantitatively by means of equilibrium sedimentation in Percoll. After centrifugation, the distribution profile of the sperm showed two peaks, i.e. the first peak near the bottom consisting of mature sperm with good motility and the second peak containing immature and/or immotile sperm. By oral administration of Me B 12 (1.0 mg/kg/day) to the oligozoospermic mice for 10 weeks, the sperm count, sperm motility, motile sperm count, diameter of seminiferous tubules and the percentage of good motile sperm with higher apparent density were increased as compared with those of the control. These results suggest that Me-B 12 enhanced the testicular function, resulting in an increased output of mature sperm.
Nguyen, Laurent; Borgs, Laurence; Vandenbosch, Renaud; Mangin, Jean-Marie; Beukelaers, Pierre; Moonen, Gustave; Gallo, Vittorio; Malgrange, Brigitte; Belachew, Shibeshih
In white matter disorders such as leukodystrophies (LD), periventricular leucomalacia (PVL), or multiple sclerosis (MS), the hypomyelination or the remyelination failure by oligodendrocyte progenitor cells involves errors in the sequence of events that normally occur during development when progenitors proliferate, migrate through the white…
Patterson, S.D.; Scarnecchia, D.L.; Congleton, J.L.
We used observational and experimental approaches to obtain information on factors affecting the timing of maturation of kokanee Oncorhynchus nerka, a semelparous, landlocked salmon. Gonadal staging criteria were developed and applied to three kokanee populations in Idaho lakes and reservoirs. Testes were classified into three stages: immature (stage one, S1), maturing (S2), and mature (S3). Ovaries were classified into eight stages: immature (S1-S3), transitional (stage S4), maturing (S5-S7), and mature (S8). Males entered the maturing stage (S2) in February through April of the spawning year. Females entered maturing stage (S5) as early as July of the year before the spawning year, and as late as March of the spawning year. Three hatchery experiments demonstrated that attainment of a larger body size 10 to 16 months before spawning increased the likelihood of initiation of maturation in both sexes. No gonads in a state of regression were observed. A gonadosomatic index above 0.1 by early July was a good indicator of a maturing male, and a gonadosomatic index above 1.0 by early July was a good indicator of a maturing female. Instantaneous growth rates were not good predictors of maturation, but attaining a size threshold of 18 to 19 cm in the fall was a good predictor of maturation the following year. This improved knowledge of kokanee maturation will permit more effectively management of the species for age, growth and size at maturity as well as for contributions to fisheries. ?? 2008 by the Northwest Scientific Association. All rights reserved.
Chaban, Y H Gerald; Chen, Ye; Hertz, Elna; Hertz, Leif
The Jimpy mouse illustrates the importance of interactions between astrocytes and oligodendrocytes. It has a mutation in Plp coding for proteolipid protein and DM20. Its behavior is normal at birth but from the age of ~2 weeks it shows severe convulsions associated with oligodendrocyte/myelination deficits and early death. A normally occurring increase in oxygen consumption by highly elevated K(+) concentrations is absent in Jimpy brain slices and cultured astrocytes, reflecting that Plp at early embryonic stages affects common precursors as also shown by the ability of conditioned medium from normal astrocytes to counteract histological abnormalities. This metabolic response is now known to reflect opening of L-channels for Ca(2+). The resulting deficiency in Ca(2+) entry has many consequences, including lack of K(+)-stimulated glycogenolysis and release of gliotransmitter ATP. Lack of purinergic stimulation compromises oligodendrocyte survival and myelination and affects connexins and K(+) channels. Mice lacking the oligodendrocytic connexins Cx32 and 47 show similar neurological dysfunction as Jimpy. This possibly reflects that K(+) released by intermodal axonal Kv channels is transported underneath a loosened myelin sheath instead of reaching the extracellular space via connexin-mediated transport to oligodendrocytes, followed by release and astrocytic Na(+),K(+)-ATPase-driven uptake with subsequent Kir4.1-facilitated release and neuronal uptake.
Bowen, Richard A; Bosco-Lauth, Angela; Syvrud, Kevin; Thomas, Anne; Meinert, Todd R; Ludlow, Deborah R; Cook, Corey; Salt, Jeremy; Ons, Ellen
Over the last years West Nile virus (WNV) lineage 2 has spread from the African to the European continent. This study was conducted to demonstrate efficacy of an inactivated, lineage 1-based, WNV vaccine (Equip WNV) against intrathecal challenge of horses with a recent isolate of lineage 2 WNV. Twenty horses, sero-negative for WNV, were enrolled and were randomly allocated to one of two treatment groups: an unvaccinated control group (T01, n=10) and a group administered with Equip WNV (T02, n=10). Horses were vaccinated at Day 0 and 21 and were challenged at day 42 with WNV lineage 2, Nea Santa/Greece/2010. Personnel performing clinical observations were blinded to treatment allocation. Sixty percent of the controls had to be euthanized after challenge compared to none of the vaccinates. A significantly lower percentage of the vaccinated animals showed clinical disease (two different clinical observations present on the same day) on six different days of study and the percentage of days with clinical disease was significantly lower in the vaccinated group. A total of 80% of the non-vaccinated horses showed viremia while only one vaccinated animal was positive by virus isolation on a single occasion. Vaccinated animals started to develop antibodies against WNV lineage 2 from day 14 (2 weeks after the first vaccination) and at day 42 (the time of onset of immunity) they had all developed a strong antibody response. Histopathology scores for all unvaccinated animals ranged from mild to very severe in each of the tissues examined (cervical spinal cord, medulla and pons), whereas in vaccinated horses 8 of 10 animals had no lesions and 2 had minimal lesions in one tissue. In conclusion, Equip WNV significantly reduced the number of viremic horses, the duration and severity of clinical signs of disease and mortality following challenge with lineage 2 WNV.
Full Text Available OPC (oligodendrocyte progenitor cell death contributes significantly to the pathology and functional deficits following hypoxic-ischemic injury in the immature brain and to deficits resulting from demyelinating diseases, trauma and degenerative disorders in the adult CNS. Glutamate toxicity is a major cause of oligodendroglial death in diverse CNS disorders, and previous studies have demonstrated that AMPA/kainate receptors require the pro-apoptotic protein Bax in OPCs undergoing apoptosis. The goal of the present study was to define the pro-apoptotic and anti-apoptotic effectors that regulate Bax in healthy OPCs and after exposure to excess glutamate in vitro and following H–I (hypoxia–ischemia in the immature rat brain. We show that Bax associates with a truncated form of Bid, a BH3-only domain protein, subsequent to glutamate treatment. Furthermore, glutamate exposure reduces Bax association with the anti-apoptotic Bcl family member, Bcl-xL. Cell fractionation studies demonstrated that both Bax and Bid translocate from the cytoplasm to mitochondria during the early stages of cell death consistent with a role for Bid as an activator, whereas Bcl-xL, which normally complexes with both Bax and Bid, disassociates from these complexes when OPCs are exposed to excess glutamate. Bax remained unactivated in the presence of insulin-like growth factor-1, and the Bcl-xL complexes were protected. Our data similarly demonstrate loss of Bcl-xL–Bax association in white matter following H–I and implicate active Bad in Bax-mediated OPC death. To identify other Bax-binding partners, we used proteomics and identified cofilin as a Bax-associated protein in OPCs. Cofilin and Bax associated in healthy OPCs, whereas the Bax–cofilin association was disrupted during glutamate-induced OPC apoptosis.
Full Text Available Abstract Background Neuroinflammation and demyelination have been suggested as mechanisms causing HIV-1 associated neurocognitive disorder (HAND. This cross-sectional cohort study explores the potential role of antibodies to myelin oligodendrocyte glycoprotein (MOG, a putative autoantigen in multiple sclerosis, in the pathogenesis of HAND. Methods IgG antibodies against MOG were measured by ELISA in sera and cerebrospinal fluid (CSF of 65 HIV-positive patients with HAND (n = 14, cerebral opportunistic infections (HIVOI, n = 25, primary HIV infection (HIVM, n = 5 and asymptomatic patients (HIVasy, n = 21. As control group HIV-negative patients with bacterial or viral CNS infections (OIND, n = 18 and other neurological diseases (OND, n = 22 were included. In a subset of HAND patients MOG antibodies were determined before and during antiviral therapy. Results In serum, significantly higher MOG antibody titers were observed in HAND compared to OND patients. In CSF, significantly higher antibody titers were observed in HAND and HIVOI patients compared to HIVasy and OND patients and in OIND compared to OND patients. CSF anti-MOG antibodies showed a high sensitivity and specificity (85.7% and 76.2% for discriminating patients with active HAND from asymptomatic HIV patients. MOG immunopositive HAND patients performed significantly worse on the HIV dementia scale and showed higher viral load in CSF. In longitudinally studied HAND patients, sustained antibody response was noted despite successful clearance of viral RNA. Conclusions Persistence of MOG antibodies despite viral clearance in a high percentage of HAND patients suggests ongoing neuroinflammation, possibly preventing recovery from HAND.
Full Text Available OPC (oligodendrocyte progenitor cell death contributes significantly to the pathology and functional deficits following hypoxic-ischemic injury in the immature brain and to deficits resulting from demyelinating diseases, trauma and degenerative disorders in the adult CNS. Glutamate toxicity is a major cause of oligodendroglial death in diverse CNS disorders, and previous studies have demonstrated that AMPA/kainate receptors require the pro-apoptotic protein Bax in OPCs undergoing apoptosis. The goal of the present study was to define the pro-apoptotic and anti-apoptotic effectors that regulate Bax in healthy OPCs and after exposure to excess glutamate in vitro and following H–I (hypoxia–ischemia in the immature rat brain. We show that Bax associates with a truncated form of Bid, a BH3-only domain protein, subsequent to glutamate treatment. Furthermore, glutamate exposure reduces Bax association with the anti-apoptotic Bcl family member, Bcl-xL. Cell fractionation studies demonstrated that both Bax and Bid translocate from the cytoplasm to mitochondria during the early stages of cell death consistent with a role for Bid as an activator, whereas Bcl-xL, which normally complexes with both Bax and Bid, disassociates from these complexes when OPCs are exposed to excess glutamate. Bax remained unactivated in the presence of insulin-like growth factor-1, and the Bcl-xL complexes were protected. Our data similarly demonstrate loss of Bcl-xL–Bax association in white matter following H–I and implicate active Bad in Bax-mediated OPC death. To identify other Bax-binding partners, we used proteomics and identified cofilin as a Bax-associated protein in OPCs. Cofilin and Bax associated in healthy OPCs, whereas the Bax–cofilin association was disrupted during glutamate-induced OPC apoptosis.
Modi, Khushbu K.; Jana, Malabendu; Mondal, Susanta; Pahan, Kalipada
Ciliary neurotrophic factor (CNTF) is a promyelinating trophic factor that plays an important role in multiple sclerosis (MS). However, mechanisms by which CNTF expression could be increased in the brain are poorly understood. Recently we have discovered anti-inflammatory and immunomodulatory activities of sodium benzoate (NaB), a metabolite of cinnamon and a widely-used food additive. Here, we delineate that NaB is also capable of increasing the mRNA and protein expression of CNTF in primary mouse astrocytes and oligodendrocytes and primary human astrocytes. Accordingly, oral administration of NaB and cinnamon led to the upregulation of astroglial and oligodendroglial CNTF in vivo in mouse brain. Induction of experimental allergic encephalomyelitis (EAE), an animal model of MS, reduced the level of CNTF in the brain, which was restored by oral administration of cinnamon. While investigating underlying mechanisms, we observed that NaB induced the activation of protein kinase A (PKA) and H-89, an inhibitor of PKA, abrogated NaB-induced expression of CNTF. The activation of cAMP response element binding (CREB) protein by NaB, the recruitment of CREB and CREB-binding protein to the CNTF promoter by NaB and the abrogation of NaB-induced expression of CNTF in astrocytes by siRNA knockdown of CREB suggest that NaB increases the expression of CNTF via the activation of CREB. These results highlight a novel myelinogenic property of NaB and cinnamon, which may be of benefit for MS and other demyelinating disorders. PMID:26399250
Liu, Zhaoyu; Xu, Dan; Wang, Shang; Chen, Yi; Li, Zhen; Gao, Xiaoyan; Jiang, Lu; Tang, Yong; Peng, Yan
The proliferative ability of oligodendrocyte progenitor cells (OPCs) varied markedly under different culture conditions. Astrocytes (ASTs) have been verified to play a major role in regulating the proliferation of OPCs through direct contact. However, the mechanisms have not been fully clarified. To investigate the effect and mechanism under AST and OPC co-culture conditions, we analyzed all connexins comprehensively in OPCs under OPC mono-culture, AST-secreted cell factor co-culture and AST-OPC direct-contact co-culture, and found that significantly differentially expressed Cx47 was the most significant. To assess whether Cx47 plays a role in proliferation, Cx47 siRNA were conducted. The result indicates that the cell cycle of OPCs was changed, and the cell proliferation was markedly inhibited. Kyoto Encyclopedia of Genes and Genomes (KEGG) predictive analysis suggested that Cx47 regulate cell cycle and proliferation by Ca(2+) activation of ERK1/2. To verify the prediction, flow cytometry, confocal microscopy, 5-ethynyl-2'-deoxyuridine (EdU), polymerase chain reaction (RT-PCR) and western blot were used. The results show that interference of Cx47 led to decreased Ca(2+) concentrations, lower p-ERK 1/2 levels, reduced transcription factor inhibitor of DNA binding 4 (Id4) expression, arrested cell cycle and reduced OPCs proliferative ability. Additionally, blocking ERK1/2 signaling caused decreased Id4 expression, arrested cell cycle in G1 phase, and reduced OPCs proliferative ability. In conclusion, ASTs can cause Ca(2+) signaling activation, ERK1/2 phosphorylation, and Id4 expression stimulation in OPCs, inducing proliferation of these cells, mainly through Cx47.
Jing SUN; Yin-quan FANG; Hong REN; Tao CHEN; Jing-jing GUO; Jun YAN; Shu SONG; Lu-yong ZHANG; Hong LIAO
Aim:To explore whether the synthetic cannabinoid receptor agonist WIN55,212-2 could protect oligodendrocyte precursor cells (OPCs)in stroke penumbra,thereby providing neuroprotection following permanent focal cerebral ischemia in rats.Methods:Adult male SD rats were subjected to permanent middle cerebral artery occlusion (p-MCAO).The animals were administered WIN55,212-2 at 2 h,and sacrificed at 24 h after the ischemic insult.The infarct volumes and brain swelling were assessed.The expression of cannabinoid receptor type 1 (CB1) in the stroke penumbra was examined using Western blot assay.The pathological changes and proliferation of neural glial antigen 2-positive OPCs (NG2+ cells) in the stroke penumbra were studied using immunohistochemistry staining.Results:p-MCAO significantly increased the expression of CB1 within the stroke penumbra with the highest level appearing at 2 h following the ischemic insult.Administration of WIN55,212-2 (9 mg/kg,iv) significantly attenuated the brain swelling,and reduced the infarct volume as well as the number of tau-immunoreactive NG2+ cells (tau-1+/NG2+ cells) in the stroke penumbra.Moreover,WIN55,212-2 significantly promoted the proliferation of NG2+ cells in the stroke penumbra and in the ipsilateral subventricular zone at 24 h following the ischemic insult.Administration of the selective CB1 antagonist rimonabant (1 mg/kg,iv) partially blocked the effects caused by WIN55,212-2.Conclusion:Tau-1 is expressed in NG2+ cells following permanent focal cerebral ischemic injury.Treatment with WIN55,212-2 reduces the number of tau-1+/NG2+ cells and promotes NG2+ cell proliferation in the stroke penumbra,which are mediated partially via CB1 and may contribute to its neuroprotective effects.
Full Text Available Aryl hydrocarbon receptors (AhRs play a critical role in various pathological and physiological processes. Although recent research has identified AhRs as a key contributor to bone metabolism following studies in systemic AhR knockout (KO or transgenic mice, the cellular and molecular mechanism(s in this process remain unclear. In this study, we explored the function of AhR in bone metabolism using AhR(RANKΔOc/ΔOc (RANK(Cre/+;AhR(flox/flox mice. We observed enhanced bone mass together with decreased resorption in both male and female 12 and 24-week-old AhR(RANKΔOc/ΔOc mice. Control mice treated with 3-methylcholanthrene (3MC, an AhR agonist, exhibited decreased bone mass and increased bone resorption, whereas AhR(CtskΔOc/ΔOc (Ctsk(Cre/+;AhR(flox/flox mice injected with 3MC appeared to have a normal bone phenotype. In vitro, bone marrow-derived macrophages (BMDMs from AhR(RANKΔOc/ΔOc mice exhibited impaired osteoclastogenesis and repressed differentiation with downregulated expression of B lymphocyte-induced maturation protein 1 (Blimp1, and cytochrome P450 genes Cyp1b1 and Cyp1a2. Collectively, our results not only demonstrated that AhR in osteoclast lineage cells is a physiologically relevant regulator of bone resorption, but also highlighted the need for further studies on the skeletal actions of AhR inhibitors in osteoclast lineage cells commonly associated with bone diseases, especially diseases linked to environmental pollutants known to induce bone loss.
Xie, Wenjie; Lorenz, Sebastian; Dolder, Silvia; Hofstetter, Willy
Osteoclasts originate from the hematopoietic stem cell and share a differentiation pathway with the cells of the monocyte/macrophage lineages. Development and activation of osteoclasts, and as a consequence regulation of bone resorption, depend on two growth factors: macrophage colony-stimulating factor and receptor activator of NF-κB ligand. Furthermore, cell development and activity are modulated by a microenvironment composed of cytokines and growth factors and of the extracellular matrix. Membrane transporters are a means for cells to interact with their environment. Within this study, the expression of proteins regulating cellular iron homeostasis in osteoclast-like cells grown from bone marrow-derived progenitors was compared to the expression of this set of proteins by monocyte/macrophage lineage cells. In differentiating osteoclasts, levels of transcripts encoding transferrin receptor 1 and divalent metal transporter 1 (Slc11A2) were increased, while levels of transcripts encoding ferroportin (Slc40A1) and natural resistance-associated macrophage protein 1 (Slc11A1) were decreased. Supplementation of the culture media with exogenous iron led to an increase in the proliferation of osteoclast progenitor cells and to the expression of a macrophage-like phenotype, while the development of osteoclasts was reduced. Upon transfer of mature OC onto a CaP substrate, iron depletion of the medium with the Fe(3+)-chelator Deferoxamine Mesylate decreased CaP dissolution by ~30 %, which could be restored by addition of exogenous iron. During the 24 h of the assay, no effects were observed on total TRAP activity. The data demonstrate transcriptional regulation of the components of cellular iron transporters during OC development and suggests that iron homeostasis may contribute to fine-tuning of the RANKL-induced OC development.
Folmes, Clifford D L; Terzic, Andre
Nutrient availability and intermediate metabolism are increasingly recognized to govern stem cell behavior. Oburoglu et al. (2014) now demonstrate that glutamine- and glucose-dependent nucleotide synthesis segregate erythroid versus myeloid differentiation during hematopoietic stem cell specification, implicating a metabolism-centric regulation of lineage choices.
The starting point for this work was to use the hypodermal seam of C. elegans as a model system to study cell fate determination. Even though the seam is a relatively simple developmental system, the mechanisms that control cell fate determination in the seam lineages are connected in a highly compl
Sarah Gregory reads an abridged version of "Putative Lineage of Novel African Usutu Virus, Central Europe.". Created: 10/15/2015 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID). Date Released: 10/15/2015.
The starting point for this work was to use the hypodermal seam of C. elegans as a model system to study cell fate determination. Even though the seam is a relatively simple developmental system, the mechanisms that control cell fate determination in the seam lineages are connected in a highly compl
Chattwood, Alex; Nagayama, Koki; Bolourani, Parvin; Harkin, Lauren; Kamjoo, Marzieh; Weeks, Gerald; Thompson, Christopher R L
In cell culture, genetically identical cells often exhibit heterogeneous behavior, with only 'lineage primed' cells responding to differentiation inducing signals. It has recently been proposed that such heterogeneity exists during normal embryonic development to allow position independent patterning based on 'salt and pepper' differentiation and sorting out. However, the molecular basis of lineage priming and how it leads to reproducible cell type proportioning are poorly understood. To address this, we employed a novel forward genetic approach in the model organism Dictyostelium discoideum. These studies reveal that the Ras-GTPase regulator gefE is required for normal lineage priming and salt and pepper differentiation. This is because Ras-GTPase activity sets the intrinsic response threshold to lineage specific differentiation signals. Importantly, we show that although gefE expression is uniform, transcription of its target, rasD, is both heterogeneous and dynamic, thus providing a novel mechanism for heterogeneity generation and position-independent differentiation. DOI: http://dx.doi.org/10.7554/eLife.01067.001.
Naccache, Samia N; Thézé, Julien; Sardi, Silvia I; Somasekar, Sneha; Greninger, Alexander L; Bandeira, Antonio C; Campos, Gubio S; Tauro, Laura B; Faria, Nuno R; Pybus, Oliver G; Chiu, Charles Y
Sequencing of isolates from patients in Bahia, Brazil, where most Zika virus cases in Brazil have been reported, resulted in 11 whole and partial Zika virus genomes. Phylogenetic analyses revealed a well-supported Bahia-specific Zika virus lineage, which indicates sustained Zika virus circulation in Salvador, Bahia's capital city, since mid-2014.
Naccache, Samia N.; Thézé, Julien; Sardi, Silvia I.; Somasekar, Sneha; Greninger, Alexander L.; Bandeira, Antonio C.; Campos, Gubio S.; Tauro, Laura B.; Faria, Nuno R.; Pybus, Oliver G.
Sequencing of isolates from patients in Bahia, Brazil, where most Zika virus cases in Brazil have been reported, resulted in 11 whole and partial Zika virus genomes. Phylogenetic analyses revealed a well-supported Bahia-specific Zika virus lineage, which indicates sustained Zika virus circulation in Salvador, Bahia’s capital city, since mid-2014. PMID:27448188
Full Text Available The long interspersed element-1 (LINE-1 or L1 and Alu elements are the most abundant mobile elements comprising 21% and 11% of the human genome, respectively. Since the divergence of human and chimpanzee lineages, these elements have vigorously created chromosomal rearrangements causing genomic difference between humans and chimpanzees by either increasing or decreasing the size of genome. Here, we report an exotic mechanism, retrotransposon recombination-mediated inversion (RRMI, that usually does not alter the amount of genomic material present. Through the comparison of the human and chimpanzee draft genome sequences, we identified 252 inversions whose respective inversion junctions can clearly be characterized. Our results suggest that L1 and Alu elements cause chromosomal inversions by either forming a secondary structure or providing a fragile site for double-strand breaks. The detailed analysis of the inversion breakpoints showed that L1 and Alu elements are responsible for at least 44% of the 252 inversion loci between human and chimpanzee lineages, including 49 RRMI loci. Among them, three RRMI loci inverted exonic regions in known genes, which implicates this mechanism in generating the genomic and phenotypic differences between human and chimpanzee lineages. This study is the first comprehensive analysis of mobile element bases inversion breakpoints between human and chimpanzee lineages, and highlights their role in primate genome evolution.
Brasier, Clive M; Franceschini, Selma; Vettraino, Anna Maria; Hansen, Everett M; Green, Sarah; Robin, Cecile; Webber, Joan F; Vannini, Andrea
Until recently Phytophthora lateralis was known only as the cause of dieback and mortality of Chamaecyparis lawsoniana in its native range in the Pacific Northwest (PNW). Since the 1990s however disease outbreaks have occurred increasingly on ornamental C. lawsoniana in Europe; and in 2007 the pathogen was discovered in soil around old growth Chamaecyparis obtusa in Taiwan, where it may be endemic. When the phenotypes of over 150 isolates of P. lateralis from Taiwan, across the PNW (British Columbia to California) and from France, the Netherlands and the UK were compared three growth rate groups were resolved: one slow growing from Taiwan, one fast growing from the PNW and Europe, and one of intermediate growth from a small area of the UK. Within these growth groups distinct subtypes were identified based on colony patterns and spore metrics and further discriminated in a multivariate analysis. The assumption that the three main growth groups represented phylogenetic units was tested by comparative sequencing of two mitochondrial and three nuclear genes. This assumption was confirmed. In addition two phenotype clusters within the Taiwan growth group were also shown to be phylogenetically distinct. These four phenotypically and genotypically unique populations are informally designated as the PNW lineage, the UK lineage, the Taiwan J lineage, and the Taiwan K lineage. Their characteristics and distribution are described and their evolution, taxonomic, and plant health significance is discussed.
The Pashtun are an ethnic group that straddles the Afghanistan-Pakistan border, and are the largest group in Afghanistan. Pashtun social structure is...proceeding upward through various levels to an entire ethnic group . These relationships are based on kinship and shared culture. Segmentary lineage
Ben-David, Uri; Nissenbaum, Jonathan; Benvenisty, Nissim
Induction of pluripotency in somatic cells has been achieved by myriad combinations of transcription factors that belong to the core pluripotency circuitry. In this issue, Shu et al. report reprogramming with lineage specifiers, lending support to the view of the pluripotent state as a fine balance between competing differentiation forces.
Cieslak, Michael; Pruvost, Melanie; Benecke, Norbert; Hofreiter, Michael; Morales, Arturo; Reissmann, Monika; Ludwig, Arne
Domestic horses represent a genetic paradox: although they have the greatest number of maternal lineages (mtDNA) of all domestic species, their paternal lineages are extremely homogeneous on the Y-chromosome. In order to address their huge mtDNA variation and the origin and history of maternal lineages in domestic horses, we analyzed 1961 partial d-loop sequences from 207 ancient remains and 1754 modern horses. The sample set ranged from Alaska and North East Siberia to the Iberian Peninsula and from the Late Pleistocene to modern times. We found a panmictic Late Pleistocene horse population ranging from Alaska to the Pyrenees. Later, during the Early Holocene and the Copper Age, more or less separated sub-populations are indicated for the Eurasian steppe region and Iberia. Our data suggest multiple domestications and introgressions of females especially during the Iron Age. Although all Eurasian regions contributed to the genetic pedigree of modern breeds, most haplotypes had their roots in Eastern Europe and Siberia. We found 87 ancient haplotypes (Pleistocene to Mediaeval Times); 56 of these haplotypes were also observed in domestic horses, although thus far only 39 haplotypes have been confirmed to survive in modern breeds. Thus, at least seventeen haplotypes of early domestic horses have become extinct during the last 5,500 years. It is concluded that the large diversity of mtDNA lineages is not a product of animal breeding but, in fact, represents ancestral variability.
Full Text Available Neural crest cells are vertebrate-specific multipotent cells that contribute to a variety of tissues including the peripheral nervous system, melanocytes, and craniofacial bones and cartilage. Abnormal development of the neural crest is associated with several human maladies including cleft/lip palate, aggressive cancers such as melanoma and neuroblastoma, and rare syndromes, like Waardenburg syndrome, a complex disorder involving hearing loss and pigment defects. We previously identified the transcription factor Pax7 as an early marker, and required component for neural crest development in chick embryos. In mammals, Pax7 is also thought to play a role in neural crest development, yet the precise contribution of Pax7 progenitors to the neural crest lineage has not been determined.Here we use Cre/loxP technology in double transgenic mice to fate map the Pax7 lineage in neural crest derivates. We find that Pax7 descendants contribute to multiple tissues including the cranial, cardiac and trunk neural crest, which in the cranial cartilage form a distinct regional pattern. The Pax7 lineage, like the Pax3 lineage, is additionally detected in some non-neural crest tissues, including a subset of the epithelial cells in specific organs.These results demonstrate a previously unappreciated widespread distribution of Pax7 descendants within and beyond the neural crest. They shed light regarding the regionally distinct phenotypes observed in Pax3 and Pax7 mutants, and provide a unique perspective into the potential roles of Pax7 during disease and development.
Full Text Available Domestic horses represent a genetic paradox: although they have the greatest number of maternal lineages (mtDNA of all domestic species, their paternal lineages are extremely homogeneous on the Y-chromosome. In order to address their huge mtDNA variation and the origin and history of maternal lineages in domestic horses, we analyzed 1961 partial d-loop sequences from 207 ancient remains and 1754 modern horses. The sample set ranged from Alaska and North East Siberia to the Iberian Peninsula and from the Late Pleistocene to modern times. We found a panmictic Late Pleistocene horse population ranging from Alaska to the Pyrenees. Later, during the Early Holocene and the Copper Age, more or less separated sub-populations are indicated for the Eurasian steppe region and Iberia. Our data suggest multiple domestications and introgressions of females especially during the Iron Age. Although all Eurasian regions contributed to the genetic pedigree of modern breeds, most haplotypes had their roots in Eastern Europe and Siberia. We found 87 ancient haplotypes (Pleistocene to Mediaeval Times; 56 of these haplotypes were also observed in domestic horses, although thus far only 39 haplotypes have been confirmed to survive in modern breeds. Thus, at least seventeen haplotypes of early domestic horses have become extinct during the last 5,500 years. It is concluded that the large diversity of mtDNA lineages is not a product of animal breeding but, in fact, represents ancestral variability.
Zarrouk, Amira; Nury, Thomas; Karym, El-Mostafa; Vejux, Anne; Sghaier, Randa; Gondcaille, Catherine; Andreoletti, Pierre; Trompier, Doriane; Savary, Stéphane; Cherkaoui-Malki, Mustapha; Debbabi, Meryam; Fromont, Agnès; Riedinger, Jean-Marc; Moreau, Thibault; Lizard, Gérard
Mitochondrial dysfunctions and oxidative stress are involved in several non demyelinating or demyelinating neurodegenerative diseases. Some of them, including multiple sclerosis (MS), are associated with lipid peroxidation processes leading to increased levels of 7-ketocholesterol (7KC). So, the eventual protective effect of dimethylfumarate (DMF), which is used for the treatment of MS, was evaluated on 7KC-treated oligodendrocytes, which are myelin synthesizing cells. To this end, murine oligodendrocytes 158N were exposed to 7KC (25, 50μM) for 24h without or with DMF (1, 25, 50μM). The biological activities of DMF associated or not with 7KC were evaluated by phase contrast microscopy, crystal violet and MTT tests. The impact on transmembrane mitochondrial potential (ΔYm), O2(-) and H2O2 production, apoptosis and autophagy was measured by microscopical and flow cytometric methods by staining with DiOC6(3), dihydroethidine and dihydrorhodamine 123, Hoechst 33342, and by Western blotting with the use of specific antibodies raised against uncleaved and cleaved caspase-3 and PARP, and LC3-I/II. DMF attenuates the different effects of 7KC, namely: cell growth inhibition and/or loss of cell adhesion, decrease of ΔΨm, O2(-) and H2O2 overproduction, PARP and caspase-3 cleavage, nuclear condensation and fragmentation, and activation of LC3-I into LC3-II. The ability of DMF to attenuate 7KC-induced reactive oxygen species overproduction, apoptosis, and autophagy on oligodendrocytes reinforces the interest for this molecule for the treatment of MS or other demyelinating diseases.
Navarro, A I; Mandyam, C D
In rodents, chronic intermittent ethanol vapor exposure (CIE) produces alcohol dependence, alters the structure and activity of pyramidal neurons and decreases the number of oligodendroglial progenitors in the medial prefrontal cortex (mPFC). In this study, adult Wistar rats were exposed to seven weeks of CIE and were withdrawn from CIE for 21 days (protracted abstinence; PA). Tissue enriched in the mPFC was processed for Western blot analysis and Golgi-Cox staining to investigate the long-lasting effects of CIE on the structure of mPFC neurons and the levels of myelin-associated proteins. PA increased dendritic arborization within apical dendrites of pyramidal neurons. These changes occurred concurrently with hypophosphorylation of the N-methyl-d-aspartate (NMDA) receptor 2B (NR2B) at Tyr-1472. PA increased myelin basic protein (MBP) levels which occurred concurrently with hypophosphorylation of the premyelinating oligodendrocyte bHLH transcription factor Olig2 in the mPFC. Given that PA is associated with increased sensitivity to stress and hypothalamic-pituitary-adrenal (HPA) axis dysregulation, and stress alters oligodendrocyte expression as a function of glucocorticoid receptor (GR) activation, the levels of total GR and phosphorylated GR were also evaluated. PA produced hypophosphorylation of the GR at Ser-232 without affecting expression of total protein. These findings demonstrate persistent and compensatory effects of ethanol in the mPFC long after cessation of CIE, including enhanced myelin production and impaired GR function. Collectively, these results suggest a novel relationship between oligodendrocytes and GR in the mPFC, in which stress may alter frontal cortex function in alcohol dependent subjects by promoting hypermyelination, thereby altering the cellular composition and white matter structure in the mPFC.
Kazama, Tomohiko; Fujie, Masaki; Endo, Tuyoshi; Kano, Koichiro
We have previously reported the establishment of preadipocyte cell lines, termed dedifferentiated fat (DFAT) cells, from mature adipocytes of various animals. DFAT cells possess long-term viability and can redifferentiate into adipocytes both in vivo and in vitro. Furthermore, DFAT cells can transdifferentiate into osteoblasts and chondrocytes under appropriate culture conditions. However, it is unclear whether DFAT cells are capable of transdifferentiating into skeletal myocytes, which is common in the mesodermal lineage. Here, we show that DFAT cells can be induced to transdifferentiate into skeletal myocytes in vitro. Myogenic induction of DFAT cells resulted in the expression of MyoD and myogenin, followed by cell fusion and formation of multinucleated cells expressing sarcomeric myosin heavy chain. These results indicate that DFAT cells derived from mature adipocytes can transdifferentiate into skeletal myocytes in vitro.
Genomic Analyses of Dominant U.S. Clonal Lineages of Phytophthora infestans Reveals a Shared Common Ancestry for Clonal Lineages US11 and US18 and a Lack of Recently Shared Ancestry Among All Other U.S. Lineages.
Knaus, B J; Tabima, J F; Davis, C E; Judelson, H S; Grünwald, N J
Populations of the potato and tomato late-blight pathogen Phytophthora infestans are well known for emerging as novel clonal lineages. These successions of dominant clones have historically been named US1 through US24, in order of appearance, since their first characterization using molecular markers. Hypothetically, these lineages can emerge through divergence from other U.S. lineages, recombination among lineages, or as novel, independent lineages originating outside the United States. We tested for the presence of phylogenetic relationships among U.S. lineages using a population of 31 whole-genome sequences, including dominant U.S. clonal lineages as well as available samples from global populations. We analyzed ancestry of the whole mitochondrial genome and samples of nuclear loci, including supercontigs 1.1 and 1.5 as well as several previously characterized coding regions. We found support for a shared ancestry among lineages US11 and US18 from the mitochondrial genome as well as from one nuclear haplotype on each supercontig analyzed. The other nuclear haplotype from each sample assorted independently, indicating an independent ancestry. We found no support for emergence of any other of the U.S. lineages from a common ancestor shared with the other U.S. lineages. Each of the U.S. clonal lineages fit a model where populations of new clonal lineages emerge via migration from a source population that is sexual in nature and potentially located in central Mexico or elsewhere. This work provides novel insights into patterns of emergence of clonal lineages in plant pathogen genomes.
Martínez-Cruz, Begoña; Mendizabal, Isabel; Harmant, Christine; de Pablo, Rosario; Ioana, Mihai; Angelicheva, Dora; Kouvatsi, Anastasia; Makukh, Halyna; Netea, Mihai G; Pamjav, Horolma; Zalán, Andrea; Tournev, Ivailo; Marushiakova, Elena; Popov, Vesselin; Bertranpetit, Jaume; Kalaydjieva, Luba; Quintana-Murci, Lluis; Comas, David
The Roma, also known as 'Gypsies', represent the largest and the most widespread ethnic minority of Europe. There is increasing evidence, based on linguistic, anthropological and genetic data, to suggest that they originated from the Indian subcontinent, with subsequent bottlenecks and undetermined gene flow from/to hosting populations during their diaspora. Further support comes from the presence of Indian uniparentally inherited lineages, such as mitochondrial DNA M and Y-chromosome H haplogroups, in a significant number of Roma individuals. However, the limited resolution of most genetic studies so far, together with the restriction of the samples used, have prevented the detection of other non-Indian founder lineages that might have been present in the proto-Roma population. We performed a high-resolution study of the uniparental genomes of 753 Roma and 984 non-Roma hosting European individuals. Roma groups show lower genetic diversity and high heterogeneity compared with non-Roma samples as a result of lower effective population size and extensive drift, consistent with a series of bottlenecks during their diaspora. We found a set of founder lineages, present in the Roma and virtually absent in the non-Roma, for the maternal (H7, J1b3, J1c1, M18, M35b, M5a1, U3, and X2d) and paternal (I-P259, J-M92, and J-M67) genomes. This lineage classification allows us to identify extensive gene flow from non-Roma to Roma groups, whereas the opposite pattern, although not negligible, is substantially lower (up to 6.3%). Finally, the exact haplotype matching analysis of both uniparental lineages consistently points to a Northwestern origin of the proto-Roma population within the Indian subcontinent.
Williams Darren W
Full Text Available Abstract Background During the development of the central nervous system (CNS of Drosophila, neuronal stem cells, the neuroblasts (NBs, first generate a set of highly diverse neurons, the primary neurons that mature to control larval behavior, and then more homogeneous sets of neurons that show delayed maturation and are primarily used in the adult. These latter, 'secondary' neurons show a complex pattern of expression of broad, which encodes a transcription factor usually associated with metamorphosis, where it acts as a key regulator in the transitions from larva and pupa. Results The Broad-Z3 (Br-Z3 isoform appears transiently in most central neurons during embryogenesis, but persists in a subset of these cells through most of larval growth. Some of the latter are embryonic-born secondary neurons, whose development is arrested until the start of metamorphosis. However, the vast bulk of the secondary neurons are generated during larval growth and bromodeoxyuridine incorporation shows that they begin expressing Br-Z3 about 7 hours after their birth, approximately the time that they have finished outgrowth to their initial targets. By the start of metamorphosis, the oldest secondary neurons have turned off Br-Z3 expression, while the remainder, with the exception of the very youngest, maintain Br-Z3 while they are interacting with potential partners in preparation for neurite elaboration. That Br-Z3 may be involved in early sprouting is suggested by ectopically expressing this isoform in remodeling primary neurons, which do not normally express Br-Z3. These cells now sprout into ectopic locations. The expression of Br-Z3 is transient and seen in all interneurons, but two other isoforms, Br-Z4 and Br-Z1, show a more selective expression. Analysis of MARCM clones shows that the Br-Z4 isoform is expressed by neurons in virtually all lineages, but only in those cells born during a window during the transition from the second to the third larval
Lee, Donald W.; Khavrutskii, Ilja V.; Wallqvist, Anders; Bavari, Sina; Cooper, Christopher L.; Chaudhury, Sidhartha
The somatic diversity of antigen-recognizing B-cell receptors (BCRs) arises from Variable (V), Diversity (D), and Joining (J) (VDJ) recombination and somatic hypermutation (SHM) during B-cell development and affinity maturation. The VDJ junction of the BCR heavy chain forms the highly variable complementarity determining region 3 (CDR3), which plays a critical role in antigen specificity and binding affinity. Tracking the selection and mutation of the CDR3 can be useful in characterizing humoral responses to infection and vaccination. Although tens to hundreds of thousands of unique BCR genes within an expressed B-cell repertoire can now be resolved with high-throughput sequencing, tracking SHMs is still challenging because existing annotation methods are often limited by poor annotation coverage, inconsistent SHM identification across the VDJ junction, or lack of B-cell lineage data. Here, we present B-cell repertoire inductive lineage and immunosequence annotator (BRILIA), an algorithm that leverages repertoire-wide sequencing data to globally improve the VDJ annotation coverage, lineage tree assembly, and SHM identification. On benchmark tests against simulated human and mouse BCR repertoires, BRILIA correctly annotated germline and clonally expanded sequences with 94 and 70% accuracy, respectively, and it has a 90% SHM-positive prediction rate in the CDR3 of heavily mutated sequences; these are substantial improvements over existing methods. We used BRILIA to process BCR sequences obtained from splenic germinal center B cells extracted from C57BL/6 mice. BRILIA returned robust B-cell lineage trees and yielded SHM patterns that are consistent across the VDJ junction and agree with known biological mechanisms of SHM. By contrast, existing BCR annotation tools, which do not account for repertoire-wide clonal relationships, systematically underestimated both the size of clonally related B-cell clusters and yielded inconsistent SHM frequencies. We demonstrate
It is now generally accepted that the four evolutionary lineages of Phytophthora ramorum (informally designated NA1, NA2, EU1, and EU2) are relatively anciently divergent populations, recently introduced into Europe and North America from different, unknown geographic locations; that recombinants between them are genetically unstable and probably...
Full Text Available Since the effectiveness of the development and operation of scientific facilities (especially those presenting specific hazards, such as ionizing radiations relies heavily on state of the art practices, such as systems engineering and product lifecycle management, configuration management (CM is becoming a key management process. However, while some maturity models exist to assess the degree of the implementation and effectiveness of many management processes, such as project management or systems engineering, there is no specific framework available to assess the degree of maturity of an organization towards CM. This paper focuses on revealing the important maturity dimensions and levels for CM as a means towards developing a CM maturity model.
Full Text Available It is important for an organization to know what capability/maturity of the process a chosen methodology could ensure. This paper is focused on DSDM Atern process maturity by CMMI. The goal is to assess DSDM Atern by CMMI-DEV version 1.3 and propose the improvements to reach CMMI maturity level 3. A capability profile ensured by DSDM Atern has been obtained. The appraisal results showed that DSDM Atern ensures CMMI maturity level 2. Constraints and problematic areas of DSDM Atern methodology were discovered. In order to reach CMMI level 3 some recommendations for DSDM Atern additions were developed.
Lisak, Robert P; Nedelkoska, Liljana; Benjamins, Joyce A
Dextromethorphan (DM), a sigma receptor agonist and NMDA receptor antagonist, protects neurons from glutamate excitotoxicity, hypoxia and ischemia, and inhibits microglial activation, but its effects on differentiation and protection of cells in the oligodendroglial lineage are unknown. It is important to protect oligodendroglia (OL) to prevent demyelination and preserve axons, and to protect oligodendroglial progenitors (OPC) to optimize myelination during development and remyelination following damage. Enriched glial cultures from newborn rat brain were used 1-2 days or 6-8 days after shakeoff for OPC or mature OL. DM had large effects on glial proliferation in less mature cultures in contrast to small variable effects in mature cultures; 1 μM DM stimulated proliferation of OPC by 4-fold, microglia (MG) by 2.5-fold and astroglia (AS) by 2-fold. In agreement with increased OPC proliferation, treatment of OPC with DM for 3 days increased the % of OPC relative to OL, with a smaller difference by 5 days, suggesting that maturation of OPC to OL was "catching up" by 5 days. DM at 2 and 20 μM protected both OL and OPC from killing by glutamate as well as NMDA, AMPA, quinolinic acid, staurosporine, and reactive oxygen species (ROS). DM did not protect against kynurenic acid, and only modestly against NO. These agents and DM were not toxic to AS or MG at the concentrations used. Thus, DM stimulates proliferation of OPC, and protects both OL and OPC against excitotoxic and inflammatory insults.
Haymes, M; Green, L
This study was undertaken to examine the independent influences of conative development (the Maslow needs hierarchy) upon behavioral aspects of prosocial orientations. It provides a behavioral demonstration of conative effects in a helping paradigm, among college-age men. A comparison of the conative data across the ages of 15-22 provided a cross-sectional view of conative development itself. Conative maturity was found to be predictive of greater helping among college-age men. Situational demands were demonstrated which tended to mask, but not override, these predispositional influences on helping. The cross-sectional data on conative development point to probable movement to early esteem concerns among high school men who have reached the conative level of love and belonging. On the other hand, the stability across the years of 15-22 of proportion of safety concerns suggests fixation of such concerns in those exhibiting them in high school. Results are discussed in terms of conative growth for development of prosocial orientations.
Marcin Czepiel,Erik Boddeke,; Sjef Copray
有关髓鞘和少突胶质细胞的研究大部分与脱髓鞘疾病相关，如多发性硬化、脑白质营养不良或脊髓损伤。髓鞘慢性脱失，慢慢导致神经退行性变，最终导致永久而严重的神经功能丧失。因此，尽快恢复髓鞘是修复脱髓鞘疾病的最有效方法。移植外源性的髓鞘再生细胞是一个有希望的治疗方法。已有多项在体和离体实验将各种具有髓鞘形成功能细胞（少突胶质细胞、施万细胞、嗅鞘细胞等）进行移植，观察其髓鞘修复功能。本综述对将人类少突胶质细胞用于治疗脱髓鞘疾病的相关研究进行总结。首先，对人类少突胶质细胞从胚胎发育晚期到产后早期的发育过程进行简要的综述。然后，对各种内源性和外源性的少突胶质细胞调节因子的研究进行总结。在离体实验中，必须调控好各种调节因子才能使培养的少突胶质细胞达到足够的数量用于移植。之后，探讨了人类少突胶质细胞的可能来源，包括一些新型的少突胶质细胞生产策略，如诱导多能干细胞诱导直接分化为少突胶质细胞。最后，本综述对人类少突胶质细胞的髓鞘再生功能和效率进行了系统的回顾。%Studies on myelination and oligodendrocyte development are inevitably linked with demyelinating conditions such as multiple sclerosis (MS), leukodystrophies or spinal cord injury (SCI). Chronic loss of myelin, subsequently leading to neurodegeneration, is the ultimate cause of severe and permanent disability. Thus, fast restoration of myelin (remyelination) is essential for circumventing demyelination-caused pathologies. Implanta-tion of exogenous remyelinating cells has been considered as a potential remyelination strategy. Researchers have examined a variety of cell types endowed with myelin-forming capacity (oligodendrocytes, Schwann cells, olfac-tory ensheathing cells etc.) in vitro and in vivo for their
In the CNS, oligodendrocytes are responsible for the formation of myelin that surrounds axons. In recent years, oligodendrocyte precursor cells (OPCs) have gained much attention for their potential of self-renew, differentiation, and remyelination of the CNS. The molecular mechanisms controlling OPCs differentiation during development, including oligodendroglial cytoskeleton, transcription, spatiotemporal regulation and axonal inhibition were reviewed.%少突胶质前体细胞形成中枢神经系统轴突的髓鞘.近年来,少突胶质前体细胞(OPC)以具有自我更新、分化及髓鞘化中枢神经系统轴突的潜能而引起关注.本文将综述在发育过程中调控OPC分化的分子机制,主要包括细胞骨架水平、转录水平、时空水平以及轴突水平等方面.
Hua, Kun; Forbes, M Elizabeth; Lichtenwalner, Robin J; Sonntag, William E; Riddle, David R
Growth hormone (GH) and insulin-like growth factor-I (IGF-I) provide trophic support during development and also appear to influence cell structure, function and replacement in the adult brain. Recent studies demonstrated effects of the GH/IGF-I axis on adult neurogenesis, but it is unclear whether the GH/IGF-I axis influences glial turnover in the normal adult brain. In the current study, we used a selective model of adult-onset GH and IGF-I deficiency to evaluate the role of GH and IGF-I in regulating glial proliferation and survival in the adult corpus callosum. GH/IGF-I-deficient dwarf rats of the Lewis strain were made GH/IGF-I replete via twice daily injections of GH starting at postnatal day 28 (P28), approximately the age at which GH pulse amplitude increases in developing rodents. GH/IGF-I deficiency was initiated in adulthood by removing animals from GH treatment. Quantitative analyses revealed that adult-onset GH/IGF-I deficiency decreased cell proliferation in the white matter and decreased the survival of newborn oligodendrocytes. These findings are consistent with the hypothesis that aging-related changes in the GH/IGF-I axis produce deficits in ongoing turnover of oligodendrocytes, which may contribute to aging-related cognitive changes and deficits in remyelination after injury.
d’Anglemont de Tassigny, Xavier; Sirerol-Piquer, M Salomé; Gómez-Pinedo, Ulises; Pardal, Ricardo; Bonilla, Sonia; Capilla-Gonzalez, Vivian; López-López, Ivette; De la Torre-Laviana, Francisco Javier; García-Verdugo, José Manuel; López-Barneo, José
Chronic hypoxemia, as evidenced in de-acclimatized high-altitude residents or in patients with chronic obstructive respiratory disorders, is a common medical condition that can produce serious neurological alterations. However, the pathogenesis of this phenomenon is unknown. We have found that adult rodents exposed for several days/weeks to hypoxia, with an arterial oxygen tension similar to that of chronically hypoxemic patients, manifest a partially irreversible structural disarrangement of the subventricular neurogenic niche (subventricular zone) characterized by displacement of neurons and myelinated axons, flattening of the ependymal cell layer, and thinning of capillary walls. Despite these abnormalities, the number of neuronal and oligodendrocyte progenitors, neuroblasts, and neurosphere-forming cells as well as the proliferative activity in subventricular zone was unchanged. These results suggest that neural stem cells and their undifferentiated progeny are resistant to hypoxia. However, in vivo and in vitro experiments indicate that severe chronic hypoxia decreases the survival of newly generated neurons and oligodendrocytes, with damage of myelin sheaths. These findings help explain the effects of hypoxia on adult neurogenesis and provide new perspectives on brain responsiveness to persistent hypoxemia. PMID:27774479
Dooley, Helen; Flajnik, Martin F
The cartilaginous fish are the oldest phylogenetic group in which all of the molecular components of the adaptive immune system have been found. Although early studies clearly showed that sharks could produce an IgM-based response following immunization, evidence for memory, affinity maturation and roles for the other isotypes (notably IgNAR) in this group remained inconclusive. The data presented here illustrate that the nurse shark (Ginglymostoma cirratum) is able to produce not only an IgM response, but we also show for the first time a highly antigen-specific IgNAR response. Additionally, under appropriate conditions, a memory response for both isotypes can be elicited. Analysis of the response shows differential expression of pentameric and monomeric IgM. Pentameric IgM provides the 'first line of defense' through high-avidity, low-affinity interaction with antigen. In contrast, monomeric IgM and IgNAR seem responsible for the specific, antigen-driven response. We propose the presence of distinct lineages of B cells in sharks. As there is no conventional isotype switching, each lineage seems pre-determined to express a single isotype (IgM versus IgNAR). However, our data suggest that there may also be specific lineages for the different forms (pentameric versus monomeric) of the IgM isotype.
San Román, Paloma; Palma, Juan Carlos; Oteo, M Dolores; Nevado, Esther
The aim of this study was to determine the validity of cervical vertebrae radiographic assessment to predict skeletal maturation. Left hand-wrist and lateral cephalometric radiographs of 958 Spanish children from 5 to 18 years of age were measured. On the left hand-wrist radiographs the classification of Grave and Brown was used to assess skeletal maturation. Cervical vertebrae maturation was evaluated with lateral cephalometric radiographs using the stages described by Lamparski and by Hassel and Farman. A new method to evaluate the cervical maturation by studying the changes in the concavity of the lower border, height, and shape of the vertebral body was created. Correlation coefficients were calculated to establish the relationship between skeletal maturation values obtained by the three classifications of vertebral and skeletal maturation measured at the wrist. All correlation values obtained were statistically significant (P vertebral bodies to evaluate the maturation stage has been designed. In the population investigated, this method is as accurate as the Hassel and Farman classification and superior to the Lamparski classification. The morphological vertebral parameter best able to estimate the maturation is the concavity of the lower border of the body.
... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Fresh Tomatoes 1 Definitions § 51.1865 Mature. Mature means that the tomato has reached the stage of development which will insure a proper completion of the ripening process, and that...
... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States Consumer Standards for Fresh Tomatoes Definitions § 51.1907 Mature. Mature means that the tomato has reached the stage of development which will insure a proper completion of the ripening process....
The aim of the article is to examine how first language attrition research on maturational constraints interprets and links its findings to current views on maturation in the field of second language acquisition. It is argued that attrition research exhibits certain inconsistencies in the interpretation of the structural characteristics of the…
Phillips, Susan D.; Strohmer, Douglas C.
Examined the relationship between decision-making style, scholastic achievement, and vocational maturity for college students (N=64). Results did not support the hypothesized relationship between rationality and attitudinal and cognitive maturity. Scholastic achievement and lack of dependent decision style were found to be moderately predictive of…
... 7 Agriculture 2 2010-01-01 2010-01-01 false Maturity. 29.6026 Section 29.6026 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6026 Maturity. The degree of ripeness. (See chart.)...
McClelland, David C.; And Others
Married couples rated their marital satisfaction and played interpersonal competitive games which revealed the success with which they interacted. Younger husbands who scored more maturely on the Stewart measure of psychosocial maturity belonged to more successful marriages, as did college-educated wives who showed less immaturity and more phallic…
Elliot, Jeffrey M.; Mantz, Concetta M.
The factors and motivations contributing to the presence of increasing numbers of mature women in college are examined, and seven proposals are offered, representing an attempt to develop a total community college program which will meet the needs of mature women students. (NHM)
McClelland, David C.; And Others
Married couples rated their marital satisfaction and played interpersonal competitive games which revealed the success with which they interacted. Younger husbands who scored more maturely on the Stewart measure of psychosocial maturity belonged to more successful marriages, as did college-educated wives who showed less immaturity and more phallic…
翁超; 卢祖能; 符辉
中枢神经系统中,髓鞘是由少突胶质细胞包绕神经轴突形成的多层脂质膜.少突胶质细胞由神经干细胞分化发育而来.研究发现,在少突胶质细胞形成、分化和成熟的发育过程中,Olig2、Sox10、Nkx2.2、Olig1和Zfp218等转录因子发挥了重要的调控作用.髓鞘的形成过程受多信号通路的共同影响,包括Wnt、PI3K和BMP-Smad等信号通路.少突胶质细胞的分化发育和髓鞘形成是一个被高度调控的过程.本文主要围绕轴突表面的配体、转录因子和表观遗传等影响髓鞘形成的相关因素的研究进展进行综述.%Myelin is multi-layer lipid membrane that surrounds and insulates axons,which is synthesized by oligodendrocyte (OL) in the central nervous system.OLs develop from neural stem cells.Researchers found that many transcription factors,such as Olig2,Soxl0,Nkx2.2,Oligl and Zfp2l8,play very important roles in the process of OL differentiation,development and maturation.Myelin formation is effected by multiple signaling pathways,including Wnt,PI3K,BMP-Smad signaling pathway.The process of OL differentiation,development and myelination is highly regulated.Here,we mainly review the recent advance in axon surface ligands,transcription factors,epigenetics and other relevant factors for myelination.
Full Text Available The relative contributions to modern European populations of Paleolithic hunter-gatherers and Neolithic farmers from the Near East have been intensely debated. Haplogroup R1b1b2 (R-M269 is the commonest European Y-chromosomal lineage, increasing in frequency from east to west, and carried by 110 million European men. Previous studies suggested a Paleolithic origin, but here we show that the geographical distribution of its microsatellite diversity is best explained by spread from a single source in the Near East via Anatolia during the Neolithic. Taken with evidence on the origins of other haplogroups, this indicates that most European Y chromosomes originate in the Neolithic expansion. This reinterpretation makes Europe a prime example of how technological and cultural change is linked with the expansion of a Y-chromosomal lineage, and the contrast of this pattern with that shown by maternally inherited mitochondrial DNA suggests a unique role for males in the transition.
Ohnuki, Shinsuke; Okada, Hiroki; Friedrich, Anne; Kanno, Yoichiro; Goshima, Tetsuya; Hasuda, Hirokazu; Inahashi, Masaaki; Okazaki, Naoto; Tamura, Hiroyasu; Nakamura, Ryo; Hirata, Dai; Fukuda, Hisashi; Shimoi, Hitoshi; Kitamoto, Katsuhiko; Watanabe, Daisuke; Schacherer, Joseph; Akao, Takeshi; Ohya, Yoshikazu
Sake yeast was developed exclusively in Japan. Its diversification during breeding remains largely uncharacterized. To evaluate the breeding processes of the sake lineage, we thoroughly investigated the phenotypes and differentiation of 27 sake yeast strains using high-dimensional, single-cell, morphological phenotyping. Although the genetic diversity of the sake yeast lineage is relatively low, its morphological diversity has expanded substantially compared to that of the Saccharomycescerevisiae species as a whole. Evaluation of the different types of breeding processes showed that the generation of hybrids (crossbreeding) has more profound effects on cell morphology than the isolation of mutants (mutation breeding). Analysis of phenotypic robustness revealed that some sake yeast strains are more morphologically heterogeneous, possibly due to impairment of cellular network hubs. This study provides a new perspective for studying yeast breeding genetics and micro-organism breeding strategies. Copyright © 2017 Ohnuki et al.
del Campo, Javier; Guillou, Laure; Hehenberger, Elisabeth; Logares, Ramiro; López-García, Purificación; Massana, Ramon
Environmental molecular surveys targeting protist diversity have unveiled novel and uncultured lineages in a variety of ecosystems, ranging from completely new high-rank lineages, to new taxa moderately related to previously described organisms. The ecological roles of some of these novel taxa have been studied, showing that in certain habitats they may be responsible for critical environmental processes. Moreover, from an evolutionary perspective they still need to be included in a more accurate and wider understanding of the eukaryotic tree of life. These seminal discoveries promoted the development and use of a wide range of more in-depth culture-independent approaches to access this diversity, from metabarcoding and metagenomics to single cell genomics and FISH. Nonetheless, culturing using classical or innovative approaches is also essential to better characterize this new diversity. Ecologists and evolutionary biologists now face the challenge of apprehending the significance of this new diversity within the eukaryotic tree of life. PMID:26996654
Darabi, Radbod; Perlingeiro, Rita C R
Embryonic stem (ES) cells are endowed with extensive ability for self renewal and differentiation. These features make them a promising candidate for cell therapy. However, despite the enthusiasm and hype surrounding the potential therapeutic use of human ES cells and more recently induced pluripotent stem (iPS) cells, to date few reports have documented successful therapeutic outcome with ES-derived cell populations. This is probably due to two main caveats associated with ES cells, their capacity to form teratomas and the challenge of isolating the appropriate therapeutic cell population from differentiating ES cells. We have focused our efforts on the derivation of skeletal muscle progenitors from ES cells and here we will discuss the strategy of reprogramming lineage choices by overexpression of a master regulator, which has proven successful for the generation of the skeletal myogenic lineage from mouse ES cells.
Heinäniemi, Merja; Nykter, Matti; Kramer, Roger; Wienecke-Baldacchino, Anke; Sinkkonen, Lasse; Zhou, Joseph Xu; Kreisberg, Richard; Kauffman, Stuart A.; Huang, Sui; Shmulevich, Ilya
The distinct cell types of multicellular organisms arise due to constraints imposed by gene regulatory networks on the collective change of gene expression across the genome, creating self-stabilizing expression states, or attractors. We compiled a resource of curated human expression data comprising 166 cell types and 2,602 transcription regulating genes and developed a data driven method built around the concept of expression reversal defined at the level of gene pairs, such as those participating in toggle switch circuits. This approach allows us to organize the cell types into their ontogenetic lineage-relationships and to reflect regulatory relationships am