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Hill RA, Nishiyama A, Hughes EG. Features, Fates, and Functions of Oligodendrocyte Precursor Cells. Cold Spring Harb Perspect Biol 2024; 16:a041425. [PMID: 38052500 PMCID: PMC10910408 DOI: 10.1101/cshperspect.a041425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Oligodendrocyte precursor cells (OPCs) are a central nervous system resident population of glia with a distinct molecular identity and an ever-increasing list of functions. OPCs generate oligodendrocytes throughout development and across the life span in most regions of the brain and spinal cord. This process involves a complex coordination of molecular checkpoints and biophysical cues from the environment that initiate the differentiation and integration of new oligodendrocytes that synthesize myelin sheaths on axons. Outside of their progenitor role, OPCs have been proposed to play other functions including the modulation of axonal and synaptic development and the participation in bidirectional signaling with neurons and other glia. Here, we review OPC identity and known functions and discuss recent findings implying other roles for these glial cells in brain physiology and pathology.
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Affiliation(s)
- Robert A Hill
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Akiko Nishiyama
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Ethan G Hughes
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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2
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Hadjiagapiou MS, Krashias G, Christodoulou C, Pantzaris M, Lambrianides A. Serum Reactive Antibodies against the N-Methyl-D-Aspartate Receptor NR2 Subunit-Could They Act as Potential Biomarkers? Int J Mol Sci 2023; 24:16170. [PMID: 38003360 PMCID: PMC10671476 DOI: 10.3390/ijms242216170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/08/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Synaptic dysfunction and disrupted communication between neuronal and glial cells play an essential role in the underlying mechanisms of multiple sclerosis (MS). Earlier studies have revealed the importance of glutamate receptors, particularly the N-methyl-D-aspartate (NMDA) receptor, in excitotoxicity, leading to abnormal synaptic transmission and damage of neurons. Our study aimed to determine whether antibodies to the NR2 subunit of NMDAR are detected in MS patients and evaluate the correlation between antibody presence and clinical outcome. Furthermore, our focus extended to examine a possible link between NR2 reactivity and anti-coagulant antibody levels as pro-inflammatory molecules associated with MS. A cross-sectional study was carried out, including 95 patients with MS and 61 age- and gender-matched healthy controls (HCs). The enzyme-linked immunosorbent assay was used to detect anti-NR2 antibodies in serum samples of participants along with IgG antibodies against factor (F)VIIa, thrombin, prothrombin, FXa, and plasmin. According to our results, significantly elevated levels of anti-NR2 antibodies were detected in MS patients compared to HCs (p < 0.05), and this holds true when we compared the Relapsing-Remitting MS course with HCs (p < 0.05). A monotonically increasing correlation was found between NR2 seropositivity and advanced disability (rs = 0.30; p < 0.01), anti-NR2 antibodies and disease worsening (rs = 0.24; p < 0.05), as well as between antibody activity against NR2 and thrombin (rs = 0.33; p < 0.01). The presence of anti-NR2 antibodies in MS patients was less associated with anti-plasmin IgG antibodies [OR:0.96 (95%CI: 0.92-0.99); p < 0.05]; however, such an association was not demonstrated when analyzing only RRMS patients. In view of our findings, NR2-reactive antibodies may play, paving the way for further research into their potential as biomarkers and therapeutic targets in MS.
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Affiliation(s)
- Maria S. Hadjiagapiou
- Department of Neuroimmunology, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus; (M.S.H.); (M.P.)
| | - George Krashias
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus; (G.K.); (C.C.)
| | - Christina Christodoulou
- Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus; (G.K.); (C.C.)
| | - Marios Pantzaris
- Department of Neuroimmunology, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus; (M.S.H.); (M.P.)
| | - Anastasia Lambrianides
- Department of Neuroimmunology, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus; (M.S.H.); (M.P.)
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3
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Myelin-associated glycoprotein activation triggers glutamate uptake by oligodendrocytes in vitro and contributes to ameliorate glutamate-mediated toxicity in vivo. Biochim Biophys Acta Mol Basis Dis 2021; 1868:166324. [PMID: 34954343 DOI: 10.1016/j.bbadis.2021.166324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 12/08/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND Myelin-associated glycoprotein (MAG) is a key molecule involved in the nurturing effect of myelin on ensheathed axons. MAG also inhibits axon outgrowth after injury. In preclinical stroke models, administration of a function-blocking anti-MAG monoclonal antibody (mAb) aimed to improve axon regeneration demonstrated reduced lesion volumes and a rapid clinical improvement, suggesting a mechanism of immediate neuroprotection rather than enhanced axon regeneration. In addition, it has been reported that antibody-mediated crosslinking of MAG can protect oligodendrocytes (OLs) against glutamate (Glu) overload by unknown mechanisms. PURPOSE To unravel the molecular mechanisms underlying the protective effect of anti-MAG therapy with a focus on neuroprotection against Glu toxicity. RESULTS MAG activation (via antibody crosslinking) triggered the clearance of extracellular Glu by its uptake into OLs via high affinity excitatory amino acid transporters. This resulted not only in protection of OLs but also nearby neurons. MAG activation led to a PKC-dependent activation of factor Nrf2 (nuclear-erythroid related factor-2) leading to antioxidant responses including increased mRNA expression of metabolic enzymes from the glutathione biosynthetic pathway and the regulatory chain of cystine/Glu antiporter system xc- increasing reduced glutathione (GSH), the main antioxidant in cells. The efficacy of early anti-MAG mAb administration was demonstrated in a preclinical model of excitotoxicity induced by intrastriatal Glu administration and extended to a model of Experimental Autoimmune Encephalitis showing axonal damage secondary to demyelination. CONCLUSIONS MAG activation triggers Glu uptake into OLs under conditions of Glu overload and induces a robust protective antioxidant response.
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Heflin JK, Sun W. Novel Toolboxes for the Investigation of Activity-Dependent Myelination in the Central Nervous System. Front Cell Neurosci 2021; 15:769809. [PMID: 34795563 PMCID: PMC8592894 DOI: 10.3389/fncel.2021.769809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 10/06/2021] [Indexed: 11/13/2022] Open
Abstract
Myelination is essential for signal processing within neural networks. Emerging data suggest that neuronal activity positively instructs myelin development and myelin adaptation during adulthood. However, the underlying mechanisms controlling activity-dependent myelination have not been fully elucidated. Myelination is a multi-step process that involves the proliferation and differentiation of oligodendrocyte precursor cells followed by the initial contact and ensheathment of axons by mature oligodendrocytes. Conventional end-point studies rarely capture the dynamic interaction between neurons and oligodendrocyte lineage cells spanning such a long temporal window. Given that such interactions and downstream signaling cascades are likely to occur within fine cellular processes of oligodendrocytes and their precursor cells, overcoming spatial resolution limitations represents another technical hurdle in the field. In this mini-review, we discuss how advanced genetic, cutting-edge imaging, and electrophysiological approaches enable us to investigate neuron-oligodendrocyte lineage cell interaction and myelination with both temporal and spatial precision.
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Affiliation(s)
- Jack Kent Heflin
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Wenjing Sun
- Department of Neuroscience, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
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5
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Periods of synchronized myelin changes shape brain function and plasticity. Nat Neurosci 2021; 24:1508-1521. [PMID: 34711959 DOI: 10.1038/s41593-021-00917-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 07/30/2021] [Indexed: 12/11/2022]
Abstract
Myelin, a lipid membrane that wraps axons, enabling fast neurotransmission and metabolic support to axons, is conventionally thought of as a static structure that is set early in development. However, recent evidence indicates that in the central nervous system (CNS), myelination is a protracted and plastic process, ongoing throughout adulthood. Importantly, myelin is emerging as a potential modulator of neuronal networks, and evidence from human studies has highlighted myelin as a major player in shaping human behavior and learning. Here we review how myelin changes throughout life and with learning. We discuss potential mechanisms of myelination at different life stages, explore whether myelin plasticity provides the regenerative potential of the CNS white matter, and question whether changes in myelin may underlie neurological disorders.
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Dias DO, Kalkitsas J, Kelahmetoglu Y, Estrada CP, Tatarishvili J, Holl D, Jansson L, Banitalebi S, Amiry-Moghaddam M, Ernst A, Huttner HB, Kokaia Z, Lindvall O, Brundin L, Frisén J, Göritz C. Pericyte-derived fibrotic scarring is conserved across diverse central nervous system lesions. Nat Commun 2021; 12:5501. [PMID: 34535655 PMCID: PMC8448846 DOI: 10.1038/s41467-021-25585-5] [Citation(s) in RCA: 90] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 08/17/2021] [Indexed: 12/04/2022] Open
Abstract
Fibrotic scar tissue limits central nervous system regeneration in adult mammals. The extent of fibrotic tissue generation and distribution of stromal cells across different lesions in the brain and spinal cord has not been systematically investigated in mice and humans. Furthermore, it is unknown whether scar-forming stromal cells have the same origin throughout the central nervous system and in different types of lesions. In the current study, we compared fibrotic scarring in human pathological tissue and corresponding mouse models of penetrating and non-penetrating spinal cord injury, traumatic brain injury, ischemic stroke, multiple sclerosis and glioblastoma. We show that the extent and distribution of stromal cells are specific to the type of lesion and, in most cases, similar between mice and humans. Employing in vivo lineage tracing, we report that in all mouse models that develop fibrotic tissue, the primary source of scar-forming fibroblasts is a discrete subset of perivascular cells, termed type A pericytes. Perivascular cells with a type A pericyte marker profile also exist in the human brain and spinal cord. We uncover type A pericyte-derived fibrosis as a conserved mechanism that may be explored as a therapeutic target to improve recovery after central nervous system lesions.
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Affiliation(s)
- David O Dias
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Jannis Kalkitsas
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Yildiz Kelahmetoglu
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Cynthia P Estrada
- Department of Clinical Neuroscience, Karolinska University Hospital, Solna, Sweden
| | | | - Daniel Holl
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Linda Jansson
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Shervin Banitalebi
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Mahmood Amiry-Moghaddam
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Aurélie Ernst
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
- Group Genome Instability in Tumors, German Cancer Research Center, Heidelberg, Germany
| | - Hagen B Huttner
- Department of Neurology, University Hospital Erlangen, Erlangen, Germany
| | - Zaal Kokaia
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Olle Lindvall
- Lund Stem Cell Center, Lund University, Lund, Sweden
| | - Lou Brundin
- Department of Clinical Neuroscience, Karolinska University Hospital, Solna, Sweden
| | - Jonas Frisén
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Christian Göritz
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
- Ming Wai Lau Centre for Reparative Medicine, Stockholm Node, Karolinska Institutet, Stockholm, Sweden.
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7
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Monje M, Káradóttir RT. The bright and the dark side of myelin plasticity: Neuron-glial interactions in health and disease. Semin Cell Dev Biol 2021; 116:10-15. [PMID: 33293232 PMCID: PMC8178421 DOI: 10.1016/j.semcdb.2020.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 12/16/2022]
Abstract
Neuron-glial interactions shape neural circuit establishment, refinement and function. One of the key neuron-glial interactions takes place between axons and oligodendroglial precursor cells. Interactions between neurons and oligodendrocyte precursor cells (OPCs) promote OPC proliferation, generation of new oligodendrocytes and myelination, shaping myelin development and ongoing adaptive myelin plasticity in the brain. Communication between neurons and OPCs can be broadly divided into paracrine and synaptic mechanisms. Following the Nobel mini-symposium "The Dark Side of the Brain" in late 2019 at the Karolinska Institutet, this mini-review will focus on the bright and dark sides of neuron-glial interactions and discuss paracrine and synaptic interactions between neurons and OPCs and their malignant counterparts.
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Affiliation(s)
- Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
| | - Ragnhildur Thóra Káradóttir
- Wellcome - Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK; Department of Physiology, BioMedical Center, Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
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8
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Glial cell type-specific gene expression in the mouse cerebrum using the piggyBac system and in utero electroporation. Sci Rep 2021; 11:4864. [PMID: 33649472 PMCID: PMC7921133 DOI: 10.1038/s41598-021-84210-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Glial cells such as astrocytes and oligodendrocytes play crucial roles in the central nervous system. To investigate the molecular mechanisms underlying the development and the biological functions of glial cells, simple and rapid techniques for glial cell-specific genetic manipulation in the mouse cerebrum would be valuable. Here we uncovered that the Gfa2 promoter is suitable for selective gene expression in astrocytes when used with the piggyBac system and in utero electroporation. In contrast, the Blbp promoter, which has been used to induce astrocyte-specific gene expression in transgenic mice, did not result in astrocyte-specific gene expression. We also identified the Plp1 and Mbp promoters could be used with the piggyBac system and in utero electroporation to induce selective gene expression in oligodendrocytes. Furthermore, using our technique, neuron-astrocyte or neuron-oligodendrocyte interactions can be visualized by labeling neurons, astrocytes and oligodendrocytes differentially. Our study provides a fundamental basis for specific transgene expression in astrocytes and/or oligodendrocytes in the mouse cerebrum.
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9
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Pease-Raissi SE, Chan JR. Building a (w)rapport between neurons and oligodendroglia: Reciprocal interactions underlying adaptive myelination. Neuron 2021; 109:1258-1273. [PMID: 33621477 DOI: 10.1016/j.neuron.2021.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/12/2021] [Accepted: 01/29/2021] [Indexed: 12/27/2022]
Abstract
Myelin, multilayered lipid-rich membrane extensions formed by oligodendrocytes around neuronal axons, is essential for fast and efficient action potential propagation in the central nervous system. Initially thought to be a static and immutable process, myelination is now appreciated to be a dynamic process capable of responding to and modulating neuronal function throughout life. While the importance of this type of plasticity, called adaptive myelination, is now well accepted, we are only beginning to understand the underlying cellular and molecular mechanisms by which neurons communicate experience-driven circuit activation to oligodendroglia and precisely how changes in oligodendrocytes and their myelin refine neuronal function. Here, we review recent findings addressing this reciprocal relationship in which neurons alter oligodendroglial form and oligodendrocytes conversely modulate neuronal function.
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Affiliation(s)
- Sarah E Pease-Raissi
- Weill Institute for Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Jonah R Chan
- Weill Institute for Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
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10
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Kamen Y, Pivonkova H, Evans KA, Káradóttir RT. A Matter of State: Diversity in Oligodendrocyte Lineage Cells. Neuroscientist 2021; 28:144-162. [PMID: 33567971 DOI: 10.1177/1073858420987208] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Oligodendrocyte precursor cells (OPCs) give rise to oligodendrocytes which myelinate axons in the central nervous system. Although classically thought to be a homogeneous population, OPCs are reported to have different developmental origins and display regional and temporal diversity in their transcriptome, response to growth factors, and physiological properties. Similarly, evidence is accumulating that myelinating oligodendrocytes display transcriptional heterogeneity. Analyzing this reported heterogeneity suggests that OPCs, and perhaps also myelinating oligodendrocytes, may exist in different functional cell states. Here, we review the evidence indicating that OPCs and oligodendrocytes are diverse, and we discuss the implications of functional OPC states for myelination in the adult brain and for myelin repair.
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Affiliation(s)
- Yasmine Kamen
- Wellcome-Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Helena Pivonkova
- Wellcome-Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Kimberley A Evans
- Wellcome-Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Ragnhildur T Káradóttir
- Wellcome-Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.,Department of Physiology, BioMedical Center, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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11
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The Wnt Effector TCF7l2 Promotes Oligodendroglial Differentiation by Repressing Autocrine BMP4-Mediated Signaling. J Neurosci 2021; 41:1650-1664. [PMID: 33452226 DOI: 10.1523/jneurosci.2386-20.2021] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 12/02/2020] [Accepted: 01/01/2021] [Indexed: 11/21/2022] Open
Abstract
Promoting oligodendrocyte (OL) differentiation represents a promising option for remyelination therapy for treating the demyelinating disease multiple sclerosis (MS). The Wnt effector transcription factor 7-like 2 (TCF7l2) was upregulated in MS lesions and had been proposed to inhibit OL differentiation. Recent data suggest the opposite yet underlying mechanisms remain elusive. Here, we unravel a previously unappreciated function of TCF7l2 in controlling autocrine bone morphogenetic protein (BMP)4-mediated signaling. Disrupting TCF7l2 in mice of both sexes results in oligodendroglial-specific BMP4 upregulation and canonical BMP4 signaling activation in vivo Mechanistically, TCF7l2 binds to Bmp4 gene regulatory element and directly represses its transcriptional activity. Functionally, enforced TCF7l2 expression promotes OL differentiation by reducing autocrine BMP4 secretion and dampening BMP4 signaling. Importantly, compound genetic disruption demonstrates that oligodendroglial-specific BMP4 deletion rescues arrested OL differentiation elicited by TCF7l2 disruption in vivo Collectively, our study reveals a novel connection between TCF7l2 and BMP4 in oligodendroglial lineage and provides new insights into augmenting TCF7l2 for promoting remyelination in demyelinating disorders such as MS.SIGNIFICANCE STATEMENT Incomplete or failed myelin repairs, primarily resulting from the arrested differentiation of myelin-forming oligodendrocytes (OLs) from oligodendroglial progenitor cells, is one of the major reasons for neurologic progression in people affected by multiple sclerosis (MS). Using in vitro culture systems and in vivo animal models, this study unraveled a previously unrecognized autocrine regulation of bone morphogenetic protein (BMP)4-mediated signaling by the Wnt effector transcription factor 7-like 2 (TCF7l2). We showed for the first time that TCF7l2 promotes oligodendroglial differentiation by repressing BMP4-mediated activity, which is dysregulated in MS lesions. Our study suggests that elevating TCF7l2 expression may be possible in overcoming arrested oligodendroglial differentiation as observed in MS patients.
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12
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Dabbah-Assadi F, Khatib N, Ginsberg Y, Weiner Z, Shamir A, Beloosesky R. Short-Term Effect of MgSO 4 on the Expression of NRG-ErbB, Dopamine, GABA, and Glutamate Systems in the Fetal Rat Brain. J Mol Neurosci 2020; 71:446-454. [PMID: 32691278 DOI: 10.1007/s12031-020-01665-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/08/2020] [Indexed: 12/16/2022]
Abstract
MgSO4 has been used for the past two decades as neuroprotective treatment in a variety of preterm conditions. Despite the putative advantages of MgSO4 as a neuroprotective agent in the preterm brain, the short- and long-term molecular function of MgSO4 as a neuroprotective agent has not been fully elucidated. Neuregulin (NRG1)-ErbB4 signaling plays a critical role in embryonic brain development, in the biology of dopaminergic, GABAergic, and glutamatergic systems. We hypothesize that this pathway may be associated with the neuroprotective role of MgSO4. The current study aims to investigate the ability of MgSO4 to modulate the normal developing expression pattern of selected genes related to the NRG1-ErbB, dopaminergic, GABAergic, and glutamatergic systems. We demonstrate that overall short-term treatment of dam rats with MgSO4 affects the expression of fetal brain NRG1, NRG3, ErbB4, GAD67, tyrosine hydroxylase (TH), dopamine D2 and D1 receptors, GluN1, and GluN2B. More specifically, the administration of MgSO4 alters the expression of NRG-ErbB, GAD67, TH, and D2R at early gestation day 16 (GD16) regardless of the activation of the maternal immune system by lipopolysaccharide (LPS). Our data suggest that MgSO4 treatment may affect the expression of major neuronal systems and pathways mostly at an early gestation day. These changes might be an initial clue (foundation stone) in the molecular mechanism that underlies the beneficial effect of MgSO4 as a neuroprotective agent for the developmental brain.
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Affiliation(s)
- Fadwa Dabbah-Assadi
- Psychobiology Research Laboratory, Mazor Mental Health Center, D.N. Oshrat, 25201, Akko, Israel.,The Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Nazar Khatib
- Department of Obstetrics and Gynecology, Rambam Medical Center, D.N. Haaleya Hashniya, 3525408, Haifa, Israel
| | - Yuval Ginsberg
- Department of Obstetrics and Gynecology, Rambam Medical Center, D.N. Haaleya Hashniya, 3525408, Haifa, Israel
| | - Ze'ev Weiner
- Department of Obstetrics and Gynecology, Rambam Medical Center, D.N. Haaleya Hashniya, 3525408, Haifa, Israel
| | - Alon Shamir
- Psychobiology Research Laboratory, Mazor Mental Health Center, D.N. Oshrat, 25201, Akko, Israel. .,The Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel.
| | - Ron Beloosesky
- The Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel. .,Department of Obstetrics and Gynecology, Rambam Medical Center, D.N. Haaleya Hashniya, 3525408, Haifa, Israel.
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13
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Bonetto G, Kamen Y, Evans KA, Káradóttir RT. Unraveling Myelin Plasticity. Front Cell Neurosci 2020; 14:156. [PMID: 32595455 PMCID: PMC7301701 DOI: 10.3389/fncel.2020.00156] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/11/2020] [Indexed: 12/24/2022] Open
Abstract
Plasticity in the central nervous system (CNS) allows for responses to changing environmental signals. While the majority of studies on brain plasticity focus on neuronal synapses, myelin plasticity has now begun to emerge as a potential modulator of neuronal networks. Oligodendrocytes (OLs) produce myelin, which provides fast signal transmission, allows for synchronization of neuronal inputs, and helps to maintain neuronal function. Thus, myelination is also thought to be involved in learning. OLs differentiate from oligodendrocyte precursor cells (OPCs), which are distributed throughout the adult brain, and myelination continues into late adulthood. This process is orchestrated by numerous cellular and molecular signals, such as axonal diameter, growth factors, extracellular signaling molecules, and neuronal activity. However, the relative importance of, and cooperation between, these signaling pathways is currently unknown. In this review, we focus on the current knowledge about myelin plasticity in the CNS. We discuss new insights into the link between this type of plasticity, learning and behavior, as well as mechanistic aspects of myelin formation that may underlie myelin plasticity, highlighting OPC diversity in the CNS.
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Affiliation(s)
- Giulia Bonetto
- Wellcome - Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Yasmine Kamen
- Wellcome - Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Kimberley Anne Evans
- Wellcome - Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Ragnhildur Thóra Káradóttir
- Wellcome - Medical Research Council Cambridge Stem Cell Institute and Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom.,Department of Physiology, Biomedical Centre, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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14
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Zhang S, Kim B, Zhu X, Gui X, Wang Y, Lan Z, Prabhu P, Fond K, Wang A, Guo F. Glial type specific regulation of CNS angiogenesis by HIFα-activated different signaling pathways. Nat Commun 2020; 11:2027. [PMID: 32332719 PMCID: PMC7181614 DOI: 10.1038/s41467-020-15656-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 03/12/2020] [Indexed: 01/13/2023] Open
Abstract
The mechanisms by which oligodendroglia modulate CNS angiogenesis remain elusive. Previous in vitro data suggest that oligodendroglia regulate CNS endothelial cell proliferation and blood vessel formation through hypoxia inducible factor alpha (HIFα)-activated Wnt (but not VEGF) signaling. Using in vivo genetic models, we show that HIFα in oligodendroglia is necessary and sufficient for angiogenesis independent of CNS regions. At the molecular level, HIFα stabilization in oligodendroglia does not perturb Wnt signaling but rather activates VEGF. At the functional level, genetically blocking oligodendroglia-derived VEGF but not Wnt significantly decreases oligodendroglial HIFα-regulated CNS angiogenesis. Blocking astroglia-derived Wnt signaling reduces astroglial HIFα-regulated CNS angiogenesis. Together, our in vivo data demonstrate that oligodendroglial HIFα regulates CNS angiogenesis through Wnt-independent and VEGF-dependent signaling. These findings suggest an alternative mechanistic understanding of CNS angiogenesis by postnatal glial cells and unveil a glial cell type-dependent HIFα-Wnt axis in regulating CNS vessel formation. In the central nervous system, the maturation of glial cells is temporally and functionally coupled with that of the vascular network during postnatal development. Here the authors show that oligodendroglial HIFα regulates CNS angiogenesis through Wnt-independent and VEGF-dependent signaling, while astroglial HIFα participates through Wnt-dependent signaling.
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Affiliation(s)
- Sheng Zhang
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA.,Department of Neurology, School of Medicine, UC Davis, Sacramento, CA, 95817, USA
| | - Bokyung Kim
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA.,Department of Neurology, School of Medicine, UC Davis, Sacramento, CA, 95817, USA
| | - Xiaoqing Zhu
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA.,Qingdao University, Qingdao, China
| | - Xuehong Gui
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA
| | - Yan Wang
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA.,Department of Neurology, School of Medicine, UC Davis, Sacramento, CA, 95817, USA
| | - Zhaohui Lan
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA.,Department of Neurology, School of Medicine, UC Davis, Sacramento, CA, 95817, USA
| | - Preeti Prabhu
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA
| | - Kenneth Fond
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA
| | - Aijun Wang
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA.,Department of Surgery, School of Medicine, UC Davis, Sacramento, CA, 95817, USA
| | - Fuzheng Guo
- Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children/UC Davis School of Medicine, Sacramento, CA, 95817, USA. .,Department of Neurology, School of Medicine, UC Davis, Sacramento, CA, 95817, USA.
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15
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Tognatta R, Karl MT, Fyffe-Maricich SL, Popratiloff A, Garrison ED, Schenck JK, Abu-Rub M, Miller RH. Astrocytes Are Required for Oligodendrocyte Survival and Maintenance of Myelin Compaction and Integrity. Front Cell Neurosci 2020; 14:74. [PMID: 32300294 PMCID: PMC7142332 DOI: 10.3389/fncel.2020.00074] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/12/2020] [Indexed: 12/16/2022] Open
Abstract
Astrocytes have been implicated in regulating oligodendrocyte development and myelination in vitro, although their functions in vivo remain less well defined. Using a novel approach to locally ablate GFAP+ astrocytes, we demonstrate that astrocytes are required for normal CNS myelin compaction during development, and for maintaining myelin integrity in the adult. Transient ablation of GFAP+ astrocytes in the mouse spinal cord during the first postnatal week reduced the numbers of mature oligodendrocytes and inhibited myelin formation, while prolonged ablation resulted in myelin that lacked compaction and structural integrity. Ablation of GFAP+ astrocytes in the adult spinal cord resulted in the rapid, local loss of myelin integrity and regional demyelination. The loss of myelin integrity induced by astrocyte ablation was greatly reduced by NMDA receptor antagonists, both in vitro and in vivo, suggesting that myelin stability was affected by elevation of local glutamate levels following astrocyte ablation. Furthermore, targeted delivery of glutamate into adult spinal cord white matter resulted in reduction of myelin basic protein expression and localized disruption of myelin compaction which was also reduced by NMDA receptor blockade. The pathology induced by localized astrocyte loss and elevated exogenous glutamate, supports the concept that astrocytes are critical for maintenance of myelin integrity in the adult CNS and may be primary targets in the initiation of demyelinating diseases of the CNS, such as Neuromyelitis Optica (NMO).
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Affiliation(s)
- Reshmi Tognatta
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States.,Gladstone Institute of Neurological Diseases, San Francisco, CA, United States
| | - Molly T Karl
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | | | - Anastas Popratiloff
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | - Eric D Garrison
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | - Jessica K Schenck
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | - Mohammad Abu-Rub
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
| | - Robert H Miller
- School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
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16
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Neuron-oligodendroglia interactions: Activity-dependent regulation of cellular signaling. Neurosci Lett 2020; 727:134916. [PMID: 32194135 DOI: 10.1016/j.neulet.2020.134916] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 03/11/2020] [Accepted: 03/15/2020] [Indexed: 12/31/2022]
Abstract
Oligodendrocyte lineage cells (oligodendroglia) and neurons engage in bidirectional communication throughout life to support healthy brain function. Recent work shows that changes in neuronal activity can modulate proliferation, differentiation, and myelination to support the formation and function of neural circuits. While oligodendroglia express a diverse collection of receptors for growth factors, signaling molecules, neurotransmitters and neuromodulators, our knowledge of the intracellular signaling pathways that are regulated by neuronal activity remains largely incomplete. Many of the pathways that modulate oligodendroglia behavior are driven by changes in intracellular calcium signaling, which may differentially affect cytoskeletal dynamics, gene expression, maturation, integration, and axonal support. Additionally, activity-dependent neuron-oligodendroglia communication plays an integral role in the recovery from demyelinating injuries. In this review, we summarize the modalities of communication between neurons and oligodendroglia and explore possible roles of activity-dependent calcium signaling in mediating cellular behavior and myelination.
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17
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Abstract
Cells of the oligodendrocyte lineage express a wide range of Ca2+ channels and receptors that regulate oligodendrocyte progenitor cell (OPC) and oligodendrocyte formation and function. Here we define those key channels and receptors that regulate Ca2+ signaling and OPC development and myelination. We then discuss how the regulation of intracellular Ca2+ in turn affects OPC and oligodendrocyte biology in the healthy nervous system and under pathological conditions. Activation of Ca2+ channels and receptors in OPCs and oligodendrocytes by neurotransmitters converges on regulating intracellular Ca2+, making Ca2+ signaling a central candidate mediator of activity-driven myelination. Indeed, recent evidence indicates that localized changes in Ca2+ in oligodendrocytes can regulate the formation and remodeling of myelin sheaths and perhaps additional functions of oligodendrocytes and OPCs. Thus, decoding how OPCs and myelinating oligodendrocytes integrate and process Ca2+ signals will be important to fully understand central nervous system formation, health, and function.
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Affiliation(s)
- Pablo M Paez
- Department of Pharmacology and Toxicology and Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, The State University of New York, University at Buffalo, Buffalo, New York 14203, USA;
| | - David A Lyons
- Centre for Discovery Brain Sciences, Centre for Multiple Sclerosis Research, and Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, United Kingdom;
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18
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Evonuk KS, Doyle RE, Moseley CE, Thornell IM, Adler K, Bingaman AM, Bevensee MO, Weaver CT, Min B, DeSilva TM. Reduction of AMPA receptor activity on mature oligodendrocytes attenuates loss of myelinated axons in autoimmune neuroinflammation. SCIENCE ADVANCES 2020; 6:eaax5936. [PMID: 31934627 PMCID: PMC6949032 DOI: 10.1126/sciadv.aax5936] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 11/08/2019] [Indexed: 06/10/2023]
Abstract
Glutamate dysregulation occurs in multiple sclerosis (MS), but whether excitotoxic mechanisms in mature oligodendrocytes contribute to demyelination and axonal injury is unexplored. Although current treatments modulate the immune system, long-term disability ensues, highlighting the need for neuroprotection. Glutamate is elevated before T2-visible white matter lesions appear in MS. We previously reported that myelin-reactive T cells provoke microglia to release glutamate from the system xc - transporter promoting myelin degradation in experimental autoimmune encephalomyelitis (EAE). Here, we explore the target for glutamate in mature oligodendrocytes. Most glutamate-stimulated calcium influx into oligodendrocyte somas is AMPA receptor (AMPAR)-mediated, and genetic deletion of AMPAR subunit GluA4 decreased intracellular calcium responses. Inducible deletion of GluA4 on mature oligodendrocytes attenuated EAE and loss of myelinated axons was selectively reduced compared to unmyelinated axons. These data link AMPAR signaling in mature oligodendrocytes to the pathophysiology of myelinated axons, demonstrating glutamate regulation as a potential neuroprotective strategy in MS.
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Affiliation(s)
- Kirsten S. Evonuk
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Ryan E. Doyle
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Carson E. Moseley
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
- University of California, San Francisco, CA, USA
| | - Ian M. Thornell
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Keith Adler
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Amanda M. Bingaman
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Mark O. Bevensee
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Casey T. Weaver
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Booki Min
- Department of Immunology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Tara M. DeSilva
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
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19
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Kula B, Chen T, Kukley M. Glutamatergic signaling between neurons and oligodendrocyte lineage cells: Is it synaptic or non‐synaptic? Glia 2019; 67:2071-2091. [DOI: 10.1002/glia.23617] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/12/2019] [Accepted: 03/18/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Bartosz Kula
- Group of Neuron Glia InteractionUniversity of Tübingen Tübingen Germany
- Graduate Training Centre for NeuroscienceUniversity of Tübingen Tübingen Germany
| | - Ting‐Jiun Chen
- Center for Neuroscience ResearchChildren's Research Institute, Children's National Medical Center Washington District of Columbia
| | - Maria Kukley
- Group of Neuron Glia InteractionUniversity of Tübingen Tübingen Germany
- Research Institute for OphthalmologyUniversity Hospital Tübingen Tübingen Germany
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20
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Chorghay Z, Káradóttir RT, Ruthazer ES. White Matter Plasticity Keeps the Brain in Tune: Axons Conduct While Glia Wrap. Front Cell Neurosci 2018; 12:428. [PMID: 30519159 PMCID: PMC6251003 DOI: 10.3389/fncel.2018.00428] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 10/30/2018] [Indexed: 12/28/2022] Open
Abstract
Precise timing of neuronal inputs is crucial for brain circuit function and development, where it contributes critically to experience-dependent plasticity. Myelination therefore provides an important adaptation mechanism for vertebrate circuits. Despite its importance to circuit activity, the interplay between neuronal activity and myelination has yet to be fully elucidated. In recent years, significant attention has been devoted to uncovering and explaining the phenomenon of white matter (WM) plasticity. Here, we summarize some of the critical evidence for modulation of the WM by neuronal activity, ranging from human diffusion tensor imaging (DTI) studies to experiments in animal models. These experiments reveal activity-dependent changes in the differentiation and proliferation of the oligodendrocyte lineage, and in the critical properties of the myelin sheaths. We discuss the implications of such changes for synaptic function and plasticity, and present the underlying mechanisms of neuron–glia communication, with a focus on glutamatergic signaling and the axomyelinic synapse. Finally, we examine evidence that myelin plasticity may be subject to critical periods. Taken together, the present review aims to provide insights into myelination in the context of brain circuit formation and function, emphasizing the bidirectional interplay between neurons and myelinating glial cells to better inform future investigations of nervous system plasticity.
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Affiliation(s)
- Zahraa Chorghay
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Ragnhildur Thóra Káradóttir
- Department of Veterinary Medicine, Wellcome Trust - Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Edward S Ruthazer
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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21
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Almeida RG. The Rules of Attraction in Central Nervous System Myelination. Front Cell Neurosci 2018; 12:367. [PMID: 30374292 PMCID: PMC6196289 DOI: 10.3389/fncel.2018.00367] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 09/27/2018] [Indexed: 12/12/2022] Open
Abstract
The wrapping of myelin around axons is crucial for the development and function of the central nervous system (CNS) of vertebrates, greatly regulating the conduction of action potentials. Oligodendrocytes, the myelinating glia of the CNS, have an intrinsic tendency to wrap myelin around any permissive structure in vitro, but in vivo, myelin is targeted with remarkable specificity only to certain axons. Despite the importance of myelination, the mechanisms by which oligodendrocytes navigate a complex milieu that includes many types of cells and their cellular projections and select only certain axons for myelination remains incompletely understood. In this Mini-review, I highlight recent studies that shed light on the molecular and cellular rules governing CNS myelin targeting.
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Affiliation(s)
- Rafael Góis Almeida
- Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
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22
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Káradóttir RT, Kuo CT. Neuronal Activity-Dependent Control of Postnatal Neurogenesis and Gliogenesis. Annu Rev Neurosci 2018; 41:139-161. [PMID: 29618286 DOI: 10.1146/annurev-neuro-072116-031054] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The addition of new neurons and oligodendroglia in the postnatal and adult mammalian brain presents distinct forms of gray and white matter plasticity. Substantial effort has been devoted to understanding the cellular and molecular mechanisms controlling postnatal neurogenesis and gliogenesis, revealing important parallels to principles governing the embryonic stages. While during central nervous system development, scripted temporal and spatial patterns of neural and glial progenitor proliferation and differentiation are necessary to create the nervous system architecture, it remains unclear what driving forces maintain and sustain postnatal neural stem cell (NSC) and oligodendrocyte progenitor cell (OPC) production of new neurons and glia. In recent years, neuronal activity has been identified as an important modulator of these processes. Using the distinct properties of neurotransmitter ionotropic and metabotropic channels to signal downstream cellular events, NSCs and OPCs share common features in their readout of neuronal activity patterns. Here we review the current evidence for neuronal activity-dependent control of NSC/OPC proliferation and differentiation in the postnatal brain, highlight some potential mechanisms used by the two progenitor populations, and discuss future studies that might advance these research areas further.
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Affiliation(s)
- Ragnhildur T Káradóttir
- Wellcome Trust - Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge CB2 1QR, United Kingdom; .,Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, United Kingdom
| | - Chay T Kuo
- Departments of Cell Biology and Neurobiology, Duke University School of Medicine, Durham, North Carolina 27710, USA; .,Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, North Carolina 27710, USA.,Institute for Brain Sciences, Duke University, Durham, North Carolina 27708, USA
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23
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Sox2 Is Essential for Oligodendroglial Proliferation and Differentiation during Postnatal Brain Myelination and CNS Remyelination. J Neurosci 2018; 38:1802-1820. [PMID: 29335358 DOI: 10.1523/jneurosci.1291-17.2018] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 12/11/2017] [Accepted: 01/08/2018] [Indexed: 11/21/2022] Open
Abstract
In the CNS, myelination and remyelination depend on the successful progression and maturation of oligodendroglial lineage cells, including proliferation and differentiation of oligodendroglial progenitor cells (OPCs). Previous studies have reported that Sox2 transiently regulates oligodendrocyte (OL) differentiation in the embryonic and perinatal spinal cord and appears dispensable for myelination in the postnatal spinal cord. However, the role of Sox2 in OL development in the brain has yet to be defined. We now report that Sox2 is an essential positive regulator of developmental myelination in the postnatal murine brain of both sexes. Stage-specific paradigms of genetic disruption demonstrated that Sox2 regulated brain myelination by coordinating upstream OPC population supply and downstream OL differentiation. Transcriptomic analyses further supported a crucial role of Sox2 in brain developmental myelination. Consistently, oligodendroglial Sox2-deficient mice developed severe tremors and ataxia, typical phenotypes indicative of hypomyelination, and displayed severe impairment of motor function and prominent deficits of brain OL differentiation and myelination persisting into the later CNS developmental stages. We also found that Sox2 was required for efficient OPC proliferation and expansion and OL regeneration during remyelination in the adult brain and spinal cord. Together, our genetic evidence reveals an essential role of Sox2 in brain myelination and CNS remyelination, and suggests that manipulation of Sox2 and/or Sox2-mediated downstream pathways may be therapeutic in promoting CNS myelin repair.SIGNIFICANCE STATEMENT Promoting myelin formation and repair has translational significance in treating myelin-related neurological disorders, such as periventricular leukomalacia and multiple sclerosis in which brain developmental myelin formation and myelin repair are severely affected, respectively. In this report, analyses of a series of genetic conditional knock-out systems targeting different oligodendrocyte stages reveal a previously unappreciated role of Sox2 in coordinating upstream proliferation and downstream differentiation of oligodendroglial lineage cells in the mouse brain during developmental myelination and CNS remyelination. Our study points to the potential of manipulating Sox2 and its downstream pathways to promote oligodendrocyte regeneration and CNS myelin repair.
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24
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Figlia G, Gerber D, Suter U. Myelination and mTOR. Glia 2017; 66:693-707. [PMID: 29210103 PMCID: PMC5836902 DOI: 10.1002/glia.23273] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/08/2017] [Accepted: 11/17/2017] [Indexed: 02/06/2023]
Abstract
Myelinating cells surround axons to accelerate the propagation of action potentials, to support axonal health, and to refine neural circuits. Myelination is metabolically demanding and, consistent with this notion, mTORC1—a signaling hub coordinating cell metabolism—has been implicated as a key signal for myelination. Here, we will discuss metabolic aspects of myelination, illustrate the main metabolic processes regulated by mTORC1, and review advances on the role of mTORC1 in myelination of the central nervous system and the peripheral nervous system. Recent progress has revealed a complex role of mTORC1 in myelinating cells that includes, besides positive regulation of myelin growth, additional critical functions in the stages preceding active myelination. Based on the available evidence, we will also highlight potential nonoverlapping roles between mTORC1 and its known main upstream pathways PI3K‐Akt, Mek‐Erk1/2, and AMPK in myelinating cells. Finally, we will discuss signals that are already known or hypothesized to be responsible for the regulation of mTORC1 activity in myelinating cells. Myelination is metabolically demanding. The metabolic regulator mTORC1 controls differentiation of myelinating cells and promotes myelin
growth. mTORC1‐independent targets of the PI3K‐Akt and Mek‐Erk1/2 pathways may also be significant in myelination.
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Affiliation(s)
- Gianluca Figlia
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich, CH 8093, Switzerland
| | - Daniel Gerber
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich, CH 8093, Switzerland
| | - Ueli Suter
- Institute of Molecular Health Sciences, Department of Biology, Swiss Federal Institute of Technology, ETH Zürich, Zürich, CH 8093, Switzerland
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25
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Gibson EM, Geraghty AC, Monje M. Bad wrap: Myelin and myelin plasticity in health and disease. Dev Neurobiol 2017; 78:123-135. [PMID: 28986960 DOI: 10.1002/dneu.22541] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 08/31/2017] [Accepted: 10/03/2017] [Indexed: 12/21/2022]
Abstract
Human central nervous system myelin development extends well into the fourth decade of life, and this protracted period underscores the potential for experience to modulate myelination. The concept of myelin plasticity implies adaptability in myelin structure and function in response to experiences during development and beyond. Mounting evidence supports this concept of neuronal activity-regulated changes in myelin-forming cells, including oligodendrocyte precursor cell proliferation, oligodendrogenesis and modulation of myelin microstructure. In healthy individuals, myelin plasticity in associative white matter structures of the brain is implicated in learning and motor function in both rodents and humans. Activity-dependent changes in myelin-forming cells may influence the function of neural networks that depend on the convergence of numerous neural signals on both a temporal and spatial scale. However, dysregulation of myelin plasticity can disadvantageously alter myelin microstructure and result in aberrant circuit function or contribute to pathological cell proliferation. Emerging roles for myelin plasticity in normal neurological function and in disease are discussed. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 123-135, 2018.
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Affiliation(s)
- Erin M Gibson
- Department of Neurology, Stanford University School of Medicine, Stanford, California, 94305
| | - Anna C Geraghty
- Department of Neurology, Stanford University School of Medicine, Stanford, California, 94305
| | - Michelle Monje
- Department of Neurology, Stanford University School of Medicine, Stanford, California, 94305
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26
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Multipotency and therapeutic potential of NG2 cells. Biochem Pharmacol 2017; 141:42-55. [DOI: 10.1016/j.bcp.2017.05.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/12/2017] [Indexed: 12/20/2022]
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27
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Philips T, Rothstein JD. Oligodendroglia: metabolic supporters of neurons. J Clin Invest 2017; 127:3271-3280. [PMID: 28862639 DOI: 10.1172/jci90610] [Citation(s) in RCA: 203] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Oligodendrocytes are glial cells that populate the entire CNS after they have differentiated from oligodendrocyte progenitor cells. From birth onward, oligodendrocytes initiate wrapping of neuronal axons with a multilamellar lipid structure called myelin. Apart from their well-established function in action potential propagation, more recent data indicate that oligodendrocytes are essential for providing metabolic support to neurons. Oligodendrocytes transfer energy metabolites to neurons through cytoplasmic "myelinic" channels and monocarboxylate transporters, which allow for the fast delivery of short-carbon-chain energy metabolites like pyruvate and lactate to neurons. These substrates are metabolized and contribute to ATP synthesis in neurons. This Review will discuss our current understanding of this metabolic supportive function of oligodendrocytes and its potential impact in human neurodegenerative disease and related animal models.
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28
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Kougioumtzidou E, Shimizu T, Hamilton NB, Tohyama K, Sprengel R, Monyer H, Attwell D, Richardson WD. Signalling through AMPA receptors on oligodendrocyte precursors promotes myelination by enhancing oligodendrocyte survival. eLife 2017; 6. [PMID: 28608780 PMCID: PMC5484614 DOI: 10.7554/elife.28080] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/07/2017] [Indexed: 01/06/2023] Open
Abstract
Myelin, made by oligodendrocytes, is essential for rapid information transfer in the central nervous system. Oligodendrocyte precursors (OPs) receive glutamatergic synaptic input from axons but how this affects their development is unclear. Murine OPs in white matter express AMPA receptor (AMPAR) subunits GluA2, GluA3 and GluA4. We generated mice in which OPs lack both GluA2 and GluA3, or all three subunits GluA2/3/4, which respectively reduced or abolished AMPAR-mediated input to OPs. In both double- and triple-knockouts OP proliferation and number were unchanged but ~25% fewer oligodendrocytes survived in the subcortical white matter during development. In triple knockouts, this shortfall persisted into adulthood. The oligodendrocyte deficit resulted in ~20% fewer myelin sheaths but the average length, number and thickness of myelin internodes made by individual oligodendrocytes appeared normal. Thus, AMPAR-mediated signalling from active axons stimulates myelin production in developing white matter by enhancing oligodendrocyte survival, without influencing myelin synthesis per se. DOI:http://dx.doi.org/10.7554/eLife.28080.001
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Affiliation(s)
- Eleni Kougioumtzidou
- Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Takahiro Shimizu
- Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Nicola B Hamilton
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Koujiro Tohyama
- The Center for Electron Microscopy and Bio-Imaging Research and Department of Physiology, Iwate Medical University, Morioka, Japan
| | - Rolf Sprengel
- Max-Planck Research Group at the Institute for Anatomy and Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology, Deutches Krebforschungzentrum, University of Heidelberg, Heidelberg, Germany
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
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29
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Fern R. The Leukocentric Theory of Neurological Disorder: A Manifesto. Neurochem Res 2017; 42:2666-2672. [DOI: 10.1007/s11064-017-2279-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/12/2017] [Accepted: 04/21/2017] [Indexed: 01/26/2023]
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30
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Herbert AL, Monk KR. Advances in myelinating glial cell development. Curr Opin Neurobiol 2017; 42:53-60. [PMID: 27930937 PMCID: PMC5316316 DOI: 10.1016/j.conb.2016.11.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/07/2016] [Accepted: 11/13/2016] [Indexed: 12/31/2022]
Abstract
In the vertebrate nervous system, the fast conduction of action potentials is potentiated by the myelin sheath, a multi-lamellar, lipid-rich structure that also provides vital trophic and metabolic support to axons. Myelin is elaborated by the plasma membrane of specialized glial cells, oligodendrocytes in the central nervous system (CNS) and Schwann cells (SCs) in the peripheral nervous system (PNS). The diseases that result from damage to myelin or glia, including multiple sclerosis and Charcot-Marie-Tooth disease, underscore the importance of these cells for human health. Therefore, an understanding of glial development and myelination is crucial in addressing the etiology of demyelinating diseases and developing patient therapies. In this review, we discuss new insights into the roles of mechanotransduction and cytoskeletal rearrangements as well as activity dependent myelination and axonal maintenance by glia. Together, these discoveries advance our knowledge of myelin and glia in nervous system health and plasticity throughout life.
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Affiliation(s)
- Amy L Herbert
- Department of Developmental Biology, Washington University School of Medicine, 660 South Euclid Ave., Saint Louis, MO 63110, USA
| | - Kelly R Monk
- Department of Developmental Biology, Washington University School of Medicine, 660 South Euclid Ave., Saint Louis, MO 63110, USA; Hope Center for Neurological Disorders, Washington University School of Medicine, 660 South Euclid Ave., Saint Louis, MO 63110, USA.
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31
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Activity-Dependent Myelination Shapes Conduction Velocity. J Neurosci 2016; 36:11585-11586. [PMID: 27852767 DOI: 10.1523/jneurosci.2727-16.2016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/07/2016] [Accepted: 10/11/2016] [Indexed: 11/21/2022] Open
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Wheeler NA, Fuss B. Extracellular cues influencing oligodendrocyte differentiation and (re)myelination. Exp Neurol 2016; 283:512-30. [PMID: 27016069 PMCID: PMC5010977 DOI: 10.1016/j.expneurol.2016.03.019] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 03/03/2016] [Accepted: 03/18/2016] [Indexed: 02/07/2023]
Abstract
There is an increasing number of neurologic disorders found to be associated with loss and/or dysfunction of the CNS myelin sheath, ranging from the classic demyelinating disease, multiple sclerosis, through CNS injury, to neuropsychiatric diseases. The disabling burden of these diseases has sparked a growing interest in gaining a better understanding of the molecular mechanisms regulating the differentiation of the myelinating cells of the CNS, oligodendrocytes (OLGs), and the process of (re)myelination. In this context, the importance of the extracellular milieu is becoming increasingly recognized. Under pathological conditions, changes in inhibitory as well as permissive/promotional cues are thought to lead to an overall extracellular environment that is obstructive for the regeneration of the myelin sheath. Given the general view that remyelination is, even though limited in human, a natural response to demyelination, targeting pathologically 'dysregulated' extracellular cues and their downstream pathways is regarded as a promising approach toward the enhancement of remyelination by endogenous (or if necessary transplanted) OLG progenitor cells. In this review, we will introduce the extracellular cues that have been implicated in the modulation of (re)myelination. These cues can be soluble, part of the extracellular matrix (ECM) or mediators of cell-cell interactions. Their inhibitory and permissive/promotional roles with regard to remyelination as well as their potential for therapeutic intervention will be discussed.
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Affiliation(s)
- Natalie A Wheeler
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States.
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Physiological Roles of Non-Neuronal NMDA Receptors. Trends Pharmacol Sci 2016; 37:750-767. [DOI: 10.1016/j.tips.2016.05.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/23/2016] [Accepted: 05/27/2016] [Indexed: 12/14/2022]
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Hughes EG, Appel B. The cell biology of CNS myelination. Curr Opin Neurobiol 2016; 39:93-100. [PMID: 27152449 PMCID: PMC4987163 DOI: 10.1016/j.conb.2016.04.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 04/19/2016] [Accepted: 04/20/2016] [Indexed: 11/21/2022]
Abstract
Myelination of axons in the central nervous system results from the remarkable ability of oligodendrocytes to wrap multiple axons with highly specialized membrane. Because myelin membrane grows as it ensheaths axons, cytoskeletal rearrangements that enable ensheathment must be coordinated with myelin production. Because the myelin sheaths of a single oligodendrocyte can differ in thickness and length, mechanisms that coordinate axon ensheathment with myelin growth likely operate within individual oligodendrocyte processes. Recent studies have revealed new information about how assembly and disassembly of actin filaments helps drive the leading edge of nascent myelin membrane around and along axons. Concurrently, other investigations have begun to uncover evidence of communication between axons and oligodendrocytes that can regulate myelin formation.
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Affiliation(s)
- Ethan G Hughes
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Bruce Appel
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045, United States; Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, United States.
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Christensen PC, Samadi-Bahrami Z, Pavlov V, Stys PK, Moore GRW. Ionotropic glutamate receptor expression in human white matter. Neurosci Lett 2016; 630:1-8. [PMID: 27443784 DOI: 10.1016/j.neulet.2016.07.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 07/14/2016] [Accepted: 07/17/2016] [Indexed: 01/01/2023]
Abstract
Glutamate is the key excitatory neurotransmitter of the central nervous system (CNS). Its role in human grey matter transmission is well understood, but this is less clear in white matter (WM). Ionotropic glutamate receptors (iGluR) are found on both neuronal cell bodies and glia as well as on myelinated axons in rodents, and rodent WM tissue is capable of glutamate release. Thus, rodent WM expresses many of the components of the traditional grey matter neuron-to-neuron synapse, but to date this has not been shown for human WM. We demonstrate the presence of iGluRs in human WM by immunofluorescence employing high-resolution spectral confocal imaging. We found that the obligatory N-methyl-d-aspartic acid (NMDA) receptor subunit GluN1 and the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunit GluA4 co-localized with myelin, oligodendroglial cell bodies and processes. Additionally, GluA4 colocalized with axons, often in distinct clusters. These findings may explain why human WM is vulnerable to excitotoxic events following acute insults such as stroke and traumatic brain injury and in more chronic inflammatory conditions such as multiple sclerosis (MS). Further exploration of human WM glutamate signalling could pave the way for developing future therapies modulating the glutamate-mediated damage in these and other CNS disorders.
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Affiliation(s)
- Pia Crone Christensen
- Hotchkiss Brain Institute, Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, T2 N 4N1, Canada
| | - Zahra Samadi-Bahrami
- ICORD, (International Collaboration on Repair Discoveries), Department of Pathology and Laboratory Medicine, University of British Columbia, Canada
| | - Vlady Pavlov
- ICORD, (International Collaboration on Repair Discoveries), Department of Pathology and Laboratory Medicine, University of British Columbia, Canada
| | - Peter K Stys
- Hotchkiss Brain Institute, Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, T2 N 4N1, Canada.
| | - G R Wayne Moore
- ICORD, (International Collaboration on Repair Discoveries), Department of Pathology and Laboratory Medicine, University of British Columbia, Canada
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Etxeberria A, Hokanson KC, Dao DQ, Mayoral SR, Mei F, Redmond SA, Ullian EM, Chan JR. Dynamic Modulation of Myelination in Response to Visual Stimuli Alters Optic Nerve Conduction Velocity. J Neurosci 2016; 36:6937-48. [PMID: 27358452 PMCID: PMC4926240 DOI: 10.1523/jneurosci.0908-16.2016] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/05/2016] [Accepted: 05/20/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Myelin controls the time required for an action potential to travel from the neuronal soma to the axon terminal, defining the temporal manner in which information is processed within the CNS. The presence of myelin, the internodal length, and the thickness of the myelin sheath are powerful structural factors that control the velocity and fidelity of action potential transmission. Emerging evidence indicates that myelination is sensitive to environmental experience and neuronal activity. Activity-dependent modulation of myelination can dynamically alter action potential conduction properties but direct functional in vivo evidence and characterization of the underlying myelin changes is lacking. We demonstrate that in mice long-term monocular deprivation increases oligodendrogenesis in the retinogeniculate pathway but shortens myelin internode lengths without affecting other structural properties of myelinated fibers. We also demonstrate that genetically attenuating synaptic glutamate neurotransmission from retinal ganglion cells phenocopies the changes observed after monocular deprivation, suggesting that glutamate may constitute a signal for myelin length regulation. Importantly, we demonstrate that visual deprivation and shortened internodes are associated with a significant reduction in nerve conduction velocity in the optic nerve. Our results reveal the importance of sensory input in the building of myelinated fibers and suggest that this activity-dependent alteration of myelination is important for modifying the conductive properties of brain circuits in response to environmental experience. SIGNIFICANCE STATEMENT Oligodendrocyte precursor cells differentiate into mature oligodendrocytes and are capable of ensheathing axons with myelin without molecular cues from neurons. However, this default myelination process can be modulated by changes in neuronal activity. Here, we show, for the first time, that experience-dependent activity modifies the length of myelin internodes along axons altering action potential conduction velocity. Such a mechanism would allow for variations in conduction velocities that provide a degree of plasticity in accordance to environmental needs. It will be important in future work to investigate how these changes in myelination and conduction velocity contribute to signal integration in postsynaptic neurons and circuit function.
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Affiliation(s)
- Ainhoa Etxeberria
- Department of Neurology, University of California, San Francisco, California 94158
| | - Kenton C Hokanson
- Department of Ophthalmology, University of California, San Francisco, California 94143, and Program in Neuroscience, University of California, San Francisco, California 94158
| | - Dang Q Dao
- Department of Ophthalmology, University of California, San Francisco, California 94143, and
| | - Sonia R Mayoral
- Department of Neurology, University of California, San Francisco, California 94158
| | - Feng Mei
- Department of Neurology, University of California, San Francisco, California 94158
| | - Stephanie A Redmond
- Department of Neurology, University of California, San Francisco, California 94158, Program in Neuroscience, University of California, San Francisco, California 94158
| | - Erik M Ullian
- Department of Ophthalmology, University of California, San Francisco, California 94143, and Program in Neuroscience, University of California, San Francisco, California 94158
| | - Jonah R Chan
- Department of Neurology, University of California, San Francisco, California 94158, Program in Neuroscience, University of California, San Francisco, California 94158
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Glutamate signalling: A multifaceted modulator of oligodendrocyte lineage cells in health and disease. Neuropharmacology 2016; 110:574-585. [PMID: 27346208 DOI: 10.1016/j.neuropharm.2016.06.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/27/2016] [Accepted: 06/16/2016] [Indexed: 01/10/2023]
Abstract
Myelin is essential for the mammalian brain to function efficiently. Whilst many factors have been associated with regulating the differentiation of oligodendroglia and myelination, glutamate signalling might be particularly important for learning-dependent myelination. The majority of myelinated projection neurons are glutamatergic. Oligodendrocyte precursor cells receive glutamatergic synaptic inputs from unmyelinated axons and oligodendrocyte lineage cells express glutamate receptors which enable them to monitor and respond to changes in neuronal activity. Yet, what role glutamate plays for oligodendroglia is not fully understood. Here, we review glutamate signalling and its effects on oligodendrocyte lineage cells, and myelination in health and disease. Furthermore, we discuss whether glutamate signalling between neurons and oligodendroglia might lay the foundation to activity-dependent white matter plasticity. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.
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Tatsumi K, Okuda H, Morita-Takemura S, Tanaka T, Isonishi A, Shinjo T, Terada Y, Wanaka A. Voluntary Exercise Induces Astrocytic Structural Plasticity in the Globus Pallidus. Front Cell Neurosci 2016; 10:165. [PMID: 27445692 PMCID: PMC4914586 DOI: 10.3389/fncel.2016.00165] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 06/07/2016] [Indexed: 12/19/2022] Open
Abstract
Changes in astrocyte morphology are primarily attributed to the fine processes where intimate connections with neurons form the tripartite synapse and participate in neurotransmission. Recent evidence has shown that neurotransmission induces dynamic synaptic remodeling, suggesting that astrocytic fine processes may adapt their morphologies to the activity in their environment. To illustrate such a neuron-glia relationship in morphological detail, we employed a double transgenic Olig2CreER/WT; ROSA26-GAP43-EGFP mice, in which Olig2-lineage cells can be visualized and traced with membrane-targeted GFP. Although Olig2-lineage cells in the adult brain usually become mature oligodendrocytes or oligodendrocyte precursor cells with NG2-proteoglycan expression, we found a population of Olig2-lineage astrocytes with bushy morphology in several brain regions. The globus pallidus (GP) preferentially contains Olig2-lineage astrocytes. Since the GP exerts pivotal motor functions in the indirect pathway of the basal ganglionic circuit, we subjected the double transgenic mice to voluntary wheel running to activate the GP and examined morphological changes of Olig2-lineage astrocytes at both the light and electron microscopic levels. The double transgenic mice were divided into three groups: control group mice were kept in a cage with a locked running wheel for 3 weeks, Runner group were allowed free access to a running wheel for 3 weeks, and the Runner-Rest group took a sedentary 3-week rest after a 3-week running period. GFP immunofluorescence analysis and immunoelectron microscopy revealed that astrocytic fine processes elaborated complex arborization in the Runner mice, and reverted to simple morphology comparable to that of the Control group in the Runner-Rest group. Our results indicated that the fine processes of the Olig2-lineage astrocytes underwent plastic changes that correlated with overall running activities, suggesting that they actively participate in motor functions.
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Affiliation(s)
- Kouko Tatsumi
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University Kashihara, Japan
| | - Hiroaki Okuda
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical UniversityKashihara, Japan; Department of Functional Anatomy, Graduate School of Medical Sciences, Kanazawa UniversityKanazawa, Japan
| | - Shoko Morita-Takemura
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University Kashihara, Japan
| | - Tatsuhide Tanaka
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University Kashihara, Japan
| | - Ayami Isonishi
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University Kashihara, Japan
| | - Takeaki Shinjo
- Department of Anesthesiology, Faculty of Medicine, Nara Medical University Kashihara, Japan
| | - Yuki Terada
- Department of Anesthesiology, Faculty of Medicine, Nara Medical University Kashihara, Japan
| | - Akio Wanaka
- Department of Anatomy and Neuroscience, Faculty of Medicine, Nara Medical University Kashihara, Japan
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Baraban M, Mensch S, Lyons DA. Adaptive myelination from fish to man. Brain Res 2016; 1641:149-161. [PMID: 26498877 PMCID: PMC4907128 DOI: 10.1016/j.brainres.2015.10.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 01/06/2023]
Abstract
Myelinated axons with nodes of Ranvier are an evolutionary elaboration common to essentially all jawed vertebrates. Myelin made by Schwann cells in our peripheral nervous system and oligodendrocytes in our central nervous system has been long known to facilitate rapid energy efficient nerve impulse propagation. However, it is now also clear, particularly in the central nervous system, that myelin is not a simple static insulator but that it is dynamically regulated throughout development and life. New myelin sheaths can be made by newly differentiating oligodendrocytes, and mature myelin sheaths can be stimulated to grow again in the adult. Furthermore, numerous studies in models from fish to man indicate that neuronal activity can affect distinct stages of oligodendrocyte development and the process of myelination itself. This begs questions as to how these effects of activity are mediated at a cellular and molecular level and whether activity-driven adaptive myelination is a feature common to all myelinated axons, or indeed all oligodendrocytes, or is specific to cells or circuits with particular functions. Here we review the recent literature on this topic, elaborate on the key outstanding questions in the field, and look forward to future studies that incorporate investigations in systems from fish to man that will provide further insight into this fundamental aspect of nervous system plasticity. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- Marion Baraban
- Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Sigrid Mensch
- Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - David A Lyons
- Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK.
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Saab AS, Tzvetavona ID, Trevisiol A, Baltan S, Dibaj P, Kusch K, Möbius W, Goetze B, Jahn HM, Huang W, Steffens H, Schomburg ED, Pérez-Samartín A, Pérez-Cerdá F, Bakhtiari D, Matute C, Löwel S, Griesinger C, Hirrlinger J, Kirchhoff F, Nave KA. Oligodendroglial NMDA Receptors Regulate Glucose Import and Axonal Energy Metabolism. Neuron 2016; 91:119-32. [PMID: 27292539 DOI: 10.1016/j.neuron.2016.05.016] [Citation(s) in RCA: 324] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 03/11/2016] [Accepted: 05/05/2016] [Indexed: 11/17/2022]
Abstract
Oligodendrocytes make myelin and support axons metabolically with lactate. However, it is unknown how glucose utilization and glycolysis are adapted to the different axonal energy demands. Spiking axons release glutamate and oligodendrocytes express NMDA receptors of unknown function. Here we show that the stimulation of oligodendroglial NMDA receptors mobilizes glucose transporter GLUT1, leading to its incorporation into the myelin compartment in vivo. When myelinated optic nerves from conditional NMDA receptor mutants are challenged with transient oxygen-glucose deprivation, they show a reduced functional recovery when returned to oxygen-glucose but are indistinguishable from wild-type when provided with oxygen-lactate. Moreover, the functional integrity of isolated optic nerves, which are electrically silent, is extended by preincubation with NMDA, mimicking axonal activity, and shortened by NMDA receptor blockers. This reveals a novel aspect of neuronal energy metabolism in which activity-dependent glutamate release enhances oligodendroglial glucose uptake and glycolytic support of fast spiking axons.
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Affiliation(s)
- Aiman S Saab
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany; Center for Integrative Physiology and Molecular Medicine, Molecular Physiology, University of Saarland, Homburg 66421, Germany; University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland
| | - Iva D Tzvetavona
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany
| | - Andrea Trevisiol
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany
| | - Selva Baltan
- Lerner Research Institute, Cleveland Clinic, Department of Neurosciences, Cleveland, OH 44195, USA
| | - Payam Dibaj
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany
| | - Kathrin Kusch
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany
| | - Wiebke Möbius
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany
| | - Bianka Goetze
- Bernstein Focus for Neurotechnology (BFNT) and School of Biology, Department of Systems Neuroscience, University of Göttingen, 37075 Göttingen, Germany
| | - Hannah M Jahn
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany; Center for Integrative Physiology and Molecular Medicine, Molecular Physiology, University of Saarland, Homburg 66421, Germany
| | - Wenhui Huang
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany; Center for Integrative Physiology and Molecular Medicine, Molecular Physiology, University of Saarland, Homburg 66421, Germany
| | - Heinz Steffens
- Institute of Physiology, University of Göttingen, 37073 Göttingen, Germany; Max Planck Institute for Biophysical Chemistry, Department of NanoBiophotonics, 37077 Göttingen, Germany
| | - Eike D Schomburg
- Institute of Physiology, University of Göttingen, 37073 Göttingen, Germany
| | - Alberto Pérez-Samartín
- Universidad del País Vasco, CIBERNED and Departamento de Neurociencias and Achucarro Basque Center for Neuroscience, Leioa 48940, Spain
| | - Fernando Pérez-Cerdá
- Universidad del País Vasco, CIBERNED and Departamento de Neurociencias and Achucarro Basque Center for Neuroscience, Leioa 48940, Spain
| | - Davood Bakhtiari
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany; Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Carlos Matute
- Universidad del País Vasco, CIBERNED and Departamento de Neurociencias and Achucarro Basque Center for Neuroscience, Leioa 48940, Spain
| | - Siegrid Löwel
- Bernstein Focus for Neurotechnology (BFNT) and School of Biology, Department of Systems Neuroscience, University of Göttingen, 37075 Göttingen, Germany
| | - Christian Griesinger
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany; Department of NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
| | - Johannes Hirrlinger
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany; Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, 04103 Leipzig, Germany
| | - Frank Kirchhoff
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany; Center for Integrative Physiology and Molecular Medicine, Molecular Physiology, University of Saarland, Homburg 66421, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany.
| | - Klaus-Armin Nave
- Max Planck Institute of Experimental Medicine, Department of Neurogenetics, Göttingen 37075, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany.
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Mitew S, Xing YL, Merson TD. Axonal activity-dependent myelination in development: Insights for myelin repair. J Chem Neuroanat 2016; 76:2-8. [PMID: 26968658 DOI: 10.1016/j.jchemneu.2016.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 03/01/2016] [Accepted: 03/07/2016] [Indexed: 12/20/2022]
Abstract
Recent advances in transgenic tools have allowed us to peek into the earliest stages of vertebrate development to study axon-glial communication in the control of peri-natal myelination. The emerging role of neuronal activity in regulating oligodendrocyte progenitor cell behavior during developmental myelination has opened up an exciting possibility-a role for neuronal activity in the early stages of remyelination. Recent work from our laboratory and others has also shown that contrary to previously established dogma in the field, complete remyelination up to pre-demyelination levels can be achieved in mouse models of MS by oligodendrogenic neural precursor cells that derive from the adult subventricular zone. These cells are electrically active and can be depolarized, suggesting that neuronal activity may have a modulatory role in their development and remyelination potential. In this review, we summarize recent advances in our understanding of the development of axon-glia communication and apply those same concepts to remyelination, with an emphasis on the particular roles of different sources of oligodendrocyte progenitor cells.
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Affiliation(s)
- Stanislaw Mitew
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia
| | - Yao Lulu Xing
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Tobias D Merson
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.
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Micu I, Plemel JR, Lachance C, Proft J, Jansen AJ, Cummins K, van Minnen J, Stys PK. The molecular physiology of the axo-myelinic synapse. Exp Neurol 2016; 276:41-50. [DOI: 10.1016/j.expneurol.2015.10.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 01/18/2023]
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Dabrowski W, Kwiecien JM, Rola R, Klapec M, Stanisz GJ, Kotlinska-Hasiec E, Oakden W, Janik R, Coote M, Frey BN, Turski WA. Prolonged Subdural Infusion of Kynurenic Acid Is Associated with Dose-Dependent Myelin Damage in the Rat Spinal Cord. PLoS One 2015; 10:e0142598. [PMID: 26562835 PMCID: PMC4643054 DOI: 10.1371/journal.pone.0142598] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 10/23/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Kynurenic acid (KYNA) is the end stage metabolite of tryptophan produced mainly by astrocytes in the central nervous system (CNS). It has neuroprotective activities but can be elevated in the neuropsychiatric disorders. Toxic effects of KYNA in the CNS are unknown. The aim of this study was to assess the effect of the subdural KYNA infusion on the spinal cord in adult rats. METHODS A total of 42 healthy adult rats were randomly assigned into six groups and were infused for 7 days with PBS (control) or 0.0002 pmol/min, 0.01 nmol/min, 0.1 nmol/min, 1 nmol/min, and 10 nmol/min of KYNA per 7 days. The effect of KYNA on spinal cord was determined using histological and electron microscopy examination. Myelin oligodendrocyte glycoprotein (MOG) was measured in the blood serum to assess a degree of myelin damage. RESULT In all rats continuous long-lasting subdural KYNA infusion was associated with myelin damage and myelin loss that was increasingly widespread in a dose-depended fashion in peripheral, sub-pial areas. Damage to myelin sheaths was uniquely related to the separation of lamellae at the intraperiod line. The damaged myelin sheaths and areas with complete loss of myelin were associated with limited loss of scattered axons while vast majority of axons in affected areas were morphologically intact. The myelin loss-causing effect of KYNA occurred with no necrosis of oligodendrocytes, with locally severe astrogliosis and no cellular inflammatory response. Additionally, subdural KYNA infusion increased blood MOG concentration. Moreover, the rats infused with the highest doses of KYNA (1 and 10 nmol/min) demonstrated adverse neurological signs including weakness and quadriplegia. CONCLUSIONS We suggest, that subdural infusion of high dose of KYNA can be used as an experimental tool for the study of mechanisms of myelin damage and regeneration. On the other hand, the administration of low, physiologically relevant doses of KYNA may help to discover the role of KYNA in control of physiological myelination process.
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Affiliation(s)
- Wojciech Dabrowski
- Department of Anaesthesiology and Intensive Therapy Medical University, Lublin, Poland
- * E-mail:
| | - Jacek M. Kwiecien
- Department of Pathology and Molecular Medicine, M. deGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Radoslaw Rola
- Department of Neurosurgery and Paediatric Neurosurgery Medical University, Lublin, Poland
| | - Michal Klapec
- Department of Orthopaedic and Traumatology Medical University, Lublin, Poland
| | - Greg J. Stanisz
- Department of Medical Biophysics, University of Toronto, Ontario, Canada
- Physical Sciences Platform, Sunnybrook Research Institute, Ontario, Canada
| | | | - Wendy Oakden
- Department of Medical Biophysics, University of Toronto, Ontario, Canada
| | - Rafal Janik
- Department of Medical Biophysics, University of Toronto, Ontario, Canada
| | - Margaret Coote
- Department of Psychiatry and Behavioural Neurosciences, M. deGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Benicio N. Frey
- Department of Psychiatry and Behavioural Neurosciences, M. deGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Waldemar A. Turski
- Department of Experimental and Clinical Pharmacology, Medical University, Lublin, Poland
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Abstract
Oligodendrocyte precursor cells (OPCs) originate in the ventricular zones (VZs) of the brain and spinal cord and migrate throughout the developing central nervous system (CNS) before differentiating into myelinating oligodendrocytes (OLs). It is not known whether OPCs or OLs from different parts of the VZ are functionally distinct. OPCs persist in the postnatal CNS, where they continue to divide and generate myelinating OLs at a decreasing rate throughout adult life in rodents. Adult OPCs respond to injury or disease by accelerating their cell cycle and increasing production of OLs to replace lost myelin. They also form synapses with unmyelinated axons and respond to electrical activity in those axons by generating more OLs and myelin locally. This experience-dependent "adaptive" myelination is important in some forms of plasticity and learning, for example, motor learning. We review the control of OL lineage development, including OL population dynamics and adaptive myelination in the adult CNS.
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Affiliation(s)
- Dwight E Bergles
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, WBSB 1001, Baltimore, Maryland 21205
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
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45
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The Wnt effector transcription factor 7-like 2 positively regulates oligodendrocyte differentiation in a manner independent of Wnt/β-catenin signaling. J Neurosci 2015; 35:5007-22. [PMID: 25810530 DOI: 10.1523/jneurosci.4787-14.2015] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Genetic or pharmacological activation of canonical Wnt/β-catenin signaling inhibits oligodendrocyte differentiation. Transcription factor 7-like 2 (TCF7l2), also known as TCF4, is a Wnt effector induced transiently in the oligodendroglial lineage. A well accepted dogma is that TCF7l2 inhibits oligodendrocyte differentiation through activation of Wnt/β-catenin signaling. We report that TCF7l2 is upregulated transiently in postmitotic, newly differentiated oligodendrocytes. Using in vivo gene conditional ablation, we found surprisingly that TCF7l2 positively regulates neonatal and postnatal mouse oligodendrocyte differentiation during developmental myelination and remyelination in a manner independent of the Wnt/β-catenin signaling pathway. We also reveal a novel role of TCF7l2 in repressing a bone morphogenetic protein signaling pathway that is known to inhibit oligodendrocyte differentiation. Thus, our study provides novel data justifying therapeutic attempts to enhance, rather than inhibit, TCF7l2 signaling to overcome arrested oligodendroglial differentiation in multiple sclerosis and other demyelinating diseases.
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Zhang Q, Shao Y, Zhao C, Cai J, Sun S. N-methyl-D-aspartate receptor antagonist MK-801 prevents apoptosis in rats that have undergone fetal spinal cord transplantation following spinal hemisection. Exp Ther Med 2014; 8:1731-1736. [PMID: 25371724 PMCID: PMC4218703 DOI: 10.3892/etm.2014.2029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 09/02/2014] [Indexed: 01/29/2023] Open
Abstract
Spinal cord injury is the main cause of paraplegia, but effective therapies for it are lacking. Embryonic spinal cord transplantation is able to repair spinal cord injury, albeit with a large amount of neuronal apoptosis remaining in the spinal cord. MK-801, an N-methyl-D-aspartate (NMDA) receptor antagonist, is able to reduce cell death by decreasing the concentration of excitatory amino acids and preventing extracellular calcium ion influx. In this study, the effect of MK-801 on the apoptosis of spinal cord neurons in rats that have received a fetal spinal cord (FSC) transplant following spinal hemisection was investigated. Wistar rats were divided into three groups: Spinal cord hemisection injury with a combination of FSC transplantation and MK-801 treatment (group A); spinal cord hemisection injury with FSC transplantation (group B); and spinal cord injury with insertion of a Gelfoam pledget (group C). The rats were sacrificed 1, 3, 7 and 14 days after the surgery. Apoptosis in spinal slices from the injured spinal cord was examined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling reaction, and the expression of B-cell lymphoma-2 (Bcl-2) was measured by immunohistochemistry. The positive cells were quantitatively analyzed using a computer image analysis system. The rate of apoptosis and the positive expression of Bcl-2 protein in the spinal cord neurons in the three groups decreased in the following order: C>B>A (P<0.05) and A>B>C (P<0.05), respectively. This indicates that treatment with the NMDA receptor antagonist MK-801 prevents apoptosis in the spinal cord neurons of rats that have undergone FSC transplantation following spinal hemisection.
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Affiliation(s)
- Qiang Zhang
- Department of Orthopedics, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, P.R. China
| | - Yang Shao
- Department of Neurology, The Second Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu 210011, P.R. China
| | - Changsong Zhao
- Department of Orthopedics, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, P.R. China
| | - Juan Cai
- Department of Orthopedics, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, P.R. China
| | - Sheng Sun
- Department of Orthopedics, Beijing Ditan Hospital, Capital Medical University, Beijing 100015, P.R. China
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47
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Martinez-Lozada Z, Waggener CT, Kim K, Zou S, Knapp PE, Hayashi Y, Ortega A, Fuss B. Activation of sodium-dependent glutamate transporters regulates the morphological aspects of oligodendrocyte maturation via signaling through calcium/calmodulin-dependent kinase IIβ's actin-binding/-stabilizing domain. Glia 2014; 62:1543-1558. [PMID: 24866099 PMCID: PMC4107011 DOI: 10.1002/glia.22699] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 05/08/2014] [Accepted: 05/09/2014] [Indexed: 02/06/2023]
Abstract
Signaling via the major excitatory amino acid glutamate has been implicated in the regulation of various aspects of the biology of oligodendrocytes, the myelinating cells of the central nervous system (CNS). In this respect, cells of the oligodendrocyte lineage have been described to express a variety of glutamate-responsive transmembrane proteins including sodium-dependent glutamate transporters. The latter have been well characterized to mediate glutamate clearance from the extracellular space. However, there is increasing evidence that they also mediate glutamate-induced intracellular signaling events. Our data presented here show that the activation of oligodendrocyte expressed sodium-dependent glutamate transporters, in particular GLT-1 and GLAST, promotes the morphological aspects of oligodendrocyte maturation. This effect was found to be associated with a transient increase in intracellular calcium levels and a transient phosphorylation event at the serine (S)(371) site of the calcium sensor calcium/calmodulin-dependent kinase type IIβ (CaMKIIβ). The potential regulatory S(371) site is located within CaMKIIβ's previously defined actin-binding/-stabilizing domain, and phosphorylation events within this domain were identified in our studies as a requirement for sodium-dependent glutamate transporter-mediated promotion of oligodendrocyte maturation. Furthermore, our data provide good evidence for a role of these phosphorylation events in mediating detachment of CaMKIIβ from filamentous (F)-actin, and hence allowing a remodeling of the oligodendrocyte's actin cytoskeleton. Taken together with our recent findings, which demonstrated a crucial role of CaMKIIβ in regulating CNS myelination in vivo, our data strongly suggest that a sodium-dependent glutamate transporter-CaMKIIβ-actin cytoskeleton axis plays an important role in the regulation of oligodendrocyte maturation and CNS myelination.
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Affiliation(s)
- Zila Martinez-Lozada
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, Virginia 23298, USA
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México D.F, México
| | - Christopher T. Waggener
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, Virginia 23298, USA
| | - Karam Kim
- Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan
| | - Shiping Zou
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, Virginia 23298, USA
| | - Pamela E. Knapp
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, Virginia 23298, USA
| | - Yasunori Hayashi
- Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan
- Saitama University Brain Science Institute, Saitama University, Saitama 338-8570, Japan
| | - Arturo Ortega
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, México D.F, México
| | - Babette Fuss
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, Virginia 23298, USA
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Sühs KW, Fairless R, Williams SK, Heine K, Cavalié A, Diem R. N-Methyl-d-Aspartate Receptor Blockade Is Neuroprotective in Experimental Autoimmune Optic Neuritis. J Neuropathol Exp Neurol 2014; 73:507-18. [DOI: 10.1097/nen.0000000000000073] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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49
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Maldonado PP, Angulo MC. Multiple Modes of Communication between Neurons and Oligodendrocyte Precursor Cells. Neuroscientist 2014; 21:266-76. [PMID: 24722526 DOI: 10.1177/1073858414530784] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
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 is a signaling pathway controlling OPC proliferation/differentiation, influencing the myelination process. However, new evidences describing non-synaptic mechanisms of communication between neurons and OPCs have revealed that neuron-OPC interactions are more complex than expected. The activation of extrasynaptic receptors by ambient neurotransmitter or local spillover and the ability of OPCs to sense neuronal activity through a potassium channel suggest that distinct modes of communication mediate different functions of OPCs in the CNS. This review discusses different mechanisms used by OPCs to interact with neurons and their potential roles during postnatal development and in brain disorders.
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Affiliation(s)
- Paloma P Maldonado
- INSERM U1128, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France The Netherlands Institute for Neuroscience, the Royal Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - María Cecilia Angulo
- INSERM U1128, Paris, France Université Paris Descartes, Sorbonne Paris Cité, Paris, France
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50
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Boullerne AI, Polak PE, Braun D, Sharp A, Pelligrino D, Feinstein DL. Effects of peptide fraction and counter ion on the development of clinical signs in experimental autoimmune encephalomyelitis. J Neurochem 2014; 129:696-703. [PMID: 24471474 DOI: 10.1111/jnc.12664] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 01/08/2014] [Accepted: 01/21/2014] [Indexed: 12/12/2022]
Abstract
The most commonly used immunogen to induce experimental autoimmune encephalomyelitis is MOG35-55 , a 21-residue peptide derived from myelin oligodendrocyte glycoprotein (MOG). In most studies, mice exhibit a chronic disease; however, in some studies mice show a transient disease. One variable that is not often controlled for is the peptide fraction of the purified MOG material, which can vary from less than 50% to over 90%, with the remainder of mass primarily comprised of the counter ion used for peptide purification. We compared the development of clinical signs in female C57Bl6 mice immunized with two commercially available MOG35-55 peptides of similar purity but different peptide fraction (MOG-A being 45%; MOG-B being 72%). A single immunization with MOG-A induced a chronic disease course with some recovery at later stages, whereas immunization with MOG-B induced a similar course of disease but with significantly lower average clinical scores despite a higher peptide content. The addition of a booster immunization significantly increased clinical severity with both preparations, and significantly reduced the average day of onset using MOG-A. To determine if the counter ion could influence disease, we compared MOG-B-containing trifluoroacetate with MOG-B-containing acetate. Although disease incidence and severity were similar, the average day of disease onset occurred approximately 5 days earlier with the use of MOG-B-containing trifluoroacetate. These results demonstrate that differences in peptide fraction influence the course of encephalomyelitis disease, which may be due in part to the levels of counter ions present in the purified material. These findings underscore the fact that a knowledge of peptide fraction is as critical as knowledge of peptide purity when using peptides from different sources.
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Affiliation(s)
- Anne I Boullerne
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, Illinois, USA
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