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Dansu DK, Selcen I, Sauma S, Prentice E, Huang D, Li M, Moyon S, Casaccia P. Histone H4 acetylation differentially modulates proliferation in adult oligodendrocyte progenitors. J Cell Biol 2024; 223:e202308064. [PMID: 39133301 DOI: 10.1083/jcb.202308064] [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] [Received: 08/11/2023] [Revised: 06/18/2024] [Accepted: 07/29/2024] [Indexed: 08/13/2024] Open
Abstract
Adult oligodendrocyte progenitors (aOPCs) generate myelinating oligodendrocytes like neonatal progenitors (nOPCs), and they also display unique functional features. Here, using unbiased histone proteomics analysis and ChIP sequencing analysis of PDGFRα+ OPCs sorted from neonatal and adult Pdgfra-H2B-EGFP reporter mice, we identify the activating H4K8ac histone mark as enriched in the aOPCs. We detect increased occupancy of the H4K8ac activating mark at chromatin locations corresponding to genes related to the progenitor state (e.g., Hes5, Gpr17), metabolic processes (e.g., Txnip, Ptdgs), and myelin components (e.g., Cnp, Mog). aOPCs showed higher levels of transcripts related to lipid metabolism and myelin, and lower levels of transcripts related to cell cycle and proliferation compared with nOPCs. In addition, pharmacological inhibition of histone acetylation decreased the expression of the H4K8ac target genes in aOPCs and decreased their proliferation. Overall, this study identifies acetylation of the histone H4K8 as a regulator of the proliferative capacity of aOPCs.
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Affiliation(s)
- David K Dansu
- Neuroscience Initiative, Advanced Science Research Center at the City University of New York, New York, NY, USA
- Graduate Program in Biochemistry, The Graduate Center of The City University of New York, New York, NY, USA
| | - Ipek Selcen
- Neuroscience Initiative, Advanced Science Research Center at the City University of New York, New York, NY, USA
- Graduate Program in Biochemistry, The Graduate Center of The City University of New York, New York, NY, USA
| | - Sami Sauma
- Neuroscience Initiative, Advanced Science Research Center at the City University of New York, New York, NY, USA
- Graduate Program in Biology, The Graduate Center of The City University of New York, New York, NY, USA
| | - Emily Prentice
- Neuroscience Initiative, Advanced Science Research Center at the City University of New York, New York, NY, USA
- Graduate Program in Biology, The Graduate Center of The City University of New York, New York, NY, USA
| | - Dennis Huang
- Neuroscience Initiative, Advanced Science Research Center at the City University of New York, New York, NY, USA
- Graduate Program in Biology, The Graduate Center of The City University of New York, New York, NY, USA
| | - Meng Li
- Norris Medical Library, University of Southern California, Los Angeles, CA, USA
| | - Sarah Moyon
- Neuroscience Initiative, Advanced Science Research Center at the City University of New York, New York, NY, USA
- Institute of NeuroPhysiopathology (INP) UMR7051, Aix-Marseille University, CNRS, Marseille, France
| | - Patrizia Casaccia
- Neuroscience Initiative, Advanced Science Research Center at the City University of New York, New York, NY, USA
- Graduate Program in Biochemistry, The Graduate Center of The City University of New York, New York, NY, USA
- Graduate Program in Biology, The Graduate Center of The City University of New York, New York, NY, USA
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Cherchi F, Venturini M, Magni G, Frulloni L, Chieca M, Buonvicino D, Santalmasi C, Rossi F, De Logu F, Coppi E, Pugliese AM. Adenosine A 2B receptors differently modulate oligodendrogliogenesis and myelination depending on their cellular localization. Glia 2024. [PMID: 39077799 DOI: 10.1002/glia.24593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 07/02/2024] [Accepted: 07/03/2024] [Indexed: 07/31/2024]
Abstract
Differentiation of oligodendrocyte precursor cells (OPCs) into mature oligodendrocytes (OLs) is a key event for axonal myelination in the brain; this process fails during demyelinating pathologies. Adenosine is emerging as an important player in oligodendrogliogenesis, by activating its metabotropic receptors (A1R, A2AR, A2BR, and A3R). We previously demonstrated that the Gs-coupled A2BR reduced differentiation of primary OPC cultures by inhibiting delayed rectifier (IK) as well as transient (IA) outward K+ currents. To deepen the unclear role of this receptor subtype in neuron-OL interplay and in myelination process, we tested the effects of different A2BR ligands in a dorsal root ganglion neuron (DRGN)/OPC cocultures, a corroborated in vitro myelination assay. The A2BR agonist, BAY60-6583, significantly reduced myelin basic protein levels but simultaneously increased myelination index in DRGN/OPC cocultures analyzed by confocal microscopy. The last effect was prevented by the selective A2BR antagonists, PSB-603 and MRS1706. To clarify this unexpected data, we wondered whether A2BRs could play a functional role on DRGNs. We first demonstrated, by immunocytochemistry, that primary DRGN monoculture expressed A2BRs. Their selective activation by BAY60-6583 enhanced DRGN excitability, as demonstrated by increased action potential firing, decreased rheobase and depolarized resting membrane potential and were prevented by PSB-603. Throughout this A2BR-dependent enhancement of neuronal activity, DRGNs could release factors to facilitate myelination processes. Finally, silencing A2BR in DRGNs alone prevents the increased myelination induced by BAY60-6583 in cocultures. In conclusion, our data suggest a different role of A2BR during oligodendrogliogenesis and myelination, depending on their activation on neurons or oligodendroglial cells.
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Affiliation(s)
- Federica Cherchi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Martina Venturini
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Giada Magni
- Cnr-Istituto di Fisica Applicata "Nello Carrara", Florence, Italy
| | - Lucia Frulloni
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Martina Chieca
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Daniela Buonvicino
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Clara Santalmasi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Francesca Rossi
- Cnr-Istituto di Fisica Applicata "Nello Carrara", Florence, Italy
| | - Francesco De Logu
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Elisabetta Coppi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
| | - Anna Maria Pugliese
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
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Barbaresi P, Fabri M, Lorenzi T, Sagrati A, Morroni M. Intrinsic organization of the corpus callosum. Front Physiol 2024; 15:1393000. [PMID: 39035452 PMCID: PMC11259024 DOI: 10.3389/fphys.2024.1393000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 05/16/2024] [Indexed: 07/23/2024] Open
Abstract
The corpus callosum-the largest commissural fiber system connecting the two cerebral hemispheres-is considered essential for bilateral sensory integration and higher cognitive functions. Most studies exploring the corpus callosum have examined either the anatomical, physiological, and neurochemical organization of callosal projections or the functional and/or behavioral aspects of the callosal connections after complete/partial callosotomy or callosal lesion. There are no works that address the intrinsic organization of the corpus callosum. We review the existing information on the activities that take place in the commissure in three sections: I) the topographical and neurochemical organization of the intracallosal fibers, II) the role of glia in the corpus callosum, and III) the role of the intracallosal neurons.
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Affiliation(s)
- Paolo Barbaresi
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Marche Polytechnic University, Ancona, Italy
| | - Mara Fabri
- Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Teresa Lorenzi
- Department of Experimental and Clinical Medicine, Section of Neuroscience and Cell Biology, Marche Polytechnic University, Ancona, Italy
| | - Andrea Sagrati
- Department of Life and Environmental Sciences, Marche Polytechnic University, Ancona, Italy
| | - Manrico Morroni
- Electron Microscopy Unit, Azienda Ospedaliero-Universitaria, Ancona, Italy
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Dansu DK, Sauma S, Huang D, Li M, Moyon S, Casaccia P. The epigenetic landscape of oligodendrocyte progenitors changes with time. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.06.579145. [PMID: 38501119 PMCID: PMC10946295 DOI: 10.1101/2024.02.06.579145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
SUMMARY Dansu et al. identify distinct histone H4 modifications as potential mechanism underlying the functional differences between adult and neonatal progenitors. While H4K8ac favors the expression of differentiation genes, their expression is halted by H4K20me3. Adult oligodendrocyte progenitors (aOPCs) generate myelinating oligodendrocytes, like neonatal progenitors (nOPCs), but they also display unique functional features. Here, using RNA-sequencing, unbiased histone proteomics analysis and ChIP-sequencing, we define the transcripts and histone marks underlying the unique properties of aOPCs. We describe the lower proliferative capacity and higher levels of expression of oligodendrocyte specific genes in aOPCs compared to nOPCs, as well as the greater levels of H4 histone marks. We also report increased occupancy of the H4K8ac mark at chromatin locations corresponding to oligodendrocyte-specific transcription factors and lipid metabolism genes. Pharmacological inhibition of H4K8ac deposition reduces the levels of these transcripts in aOPCs, rendering their transcriptome more similar to nOPCs. The repressive H4K20me3 mark is also higher in aOPCs compared to nOPCs and pharmacological inhibition of its deposition results in increased levels of genes related to the mature oligodendrocyte state. Overall, this study identifies two histone marks which are important for the unique transcriptional and functional identity of aOPCs.
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Gutierrez BA, González-Coronel JM, Arellano RO, Limon A. Transcriptional and bioinformatic analysis of GABA A receptors expressed in oligodendrocyte progenitor cells from the human brain. Front Mol Neurosci 2023; 16:1279232. [PMID: 37953877 PMCID: PMC10637375 DOI: 10.3389/fnmol.2023.1279232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/12/2023] [Indexed: 11/14/2023] Open
Abstract
Introduction Oligodendrocyte progenitor cells (OPCs) are vital for neuronal myelination and remyelination in the central nervous system. While the molecular mechanisms involved in OPCs' differentiation and maturation are not completely understood, GABA is known to positively influence these processes through the activation of GABAA receptors (GABAARs). The molecular identity of GABAARs expressed in human OPCs remains unknown, which restricts their specific pharmacological modulation to directly assess their role in oligodendrocytes' maturation and remyelination. Methods In this study, we conducted a transcriptomic analysis to investigate the molecular stoichiometry of GABAARs in OPCs from the human brain. Using eight available transcriptomic datasets from the human brain cortex of control individuals, we analyzed the mRNA expression of all 19 known GABAARs subunit genes in OPCs, with variations observed across different ages. Results Our analysis indicated that the most expressed subunits in OPCs are α1-3, β1-3, γ1-3, and ε. Moreover, we determined that the combination of any α with β2 and γ2 is likely to form heteropentameric GABAARs in OPCs. Importantly, we also found a strong correlation between GABAAR subunits and transcripts for postsynaptic scaffold proteins, suggesting the potential postsynaptic clustering of GABAARs in OPCs. Discussion This study presents the first transcriptional-level identification of GABAAR subunits expressed in human OPCs, providing potential receptor combinations. Understanding the molecular composition of GABAARs in OPCs not only enhances our knowledge of the underlying mechanisms in oligodendrocyte maturation but also opens avenues for targeted pharmacological interventions aimed at modulating these receptors to promote remyelination in neurological disorders.
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Affiliation(s)
- Berenice A. Gutierrez
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX, United States
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Mexico
| | - José Manuel González-Coronel
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Mexico
| | - Rogelio O. Arellano
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Juriquilla, Mexico
| | - Agenor Limon
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, TX, United States
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Xiao Y, Czopka T. Myelination-independent functions of oligodendrocyte precursor cells in health and disease. Nat Neurosci 2023; 26:1663-1669. [PMID: 37653126 DOI: 10.1038/s41593-023-01423-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 07/27/2023] [Indexed: 09/02/2023]
Abstract
Oligodendrocyte precursor cells (OPCs) are a population of tissue-resident glial cells found throughout the CNS, constituting approximately 5% of all CNS cells and persisting from development to adulthood and aging. The canonical role of OPCs is to give rise to myelinating oligodendrocytes. However, additional functions of OPCs beyond this traditional role as precursors have been suggested for a long time. In this Perspective, we provide an overview of the multiple myelination-independent functions that have been described for OPCs in the context of neuron development, angiogenesis, inflammatory response, axon regeneration and their recently discovered roles in neural circuit remodeling.
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Affiliation(s)
- Yan Xiao
- Institute of Neuronal Cell Biology, Technical University of Munich, Munich, Germany
| | - Tim Czopka
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.
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Perez-Gianmarco L, Kurt B, Kukley M. Technical approaches and challenges to study AMPA receptors in oligodendrocyte lineage cells: Past, present, and future. Glia 2023; 71:819-847. [PMID: 36453615 DOI: 10.1002/glia.24305] [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: 06/02/2022] [Revised: 11/05/2022] [Accepted: 11/10/2022] [Indexed: 12/03/2022]
Abstract
Receptors for α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPARs) are ligand-gated ionotropic receptors for glutamate that is a major excitatory neurotransmitter in the central nervous system. AMPARs are located at postsynaptic sites of neuronal synapses where they mediate fast synaptic signaling and synaptic plasticity. Remarkably, AMPARs are also expressed by glial cells. Their expression by the oligodendrocyte (OL) lineage cells is of special interest because AMPARs mediate fast synaptic communication between neurons and oligodendrocyte progenitor cells (OPCs), modulate proliferation and differentiation of OPCs, and may also be involved in regulation of myelination. On the other hand, during pathological conditions, AMPARs may mediate damage of the OL lineage cells. In the present review, we focus on the technical approaches that have been used to study AMPARs in the OL lineage cells, and discuss future perspectives of AMPAR research in these glial cells.
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Affiliation(s)
- Lucila Perez-Gianmarco
- Laboratory of Neuronal and Glial Physiology, Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neurosciences, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Begüm Kurt
- Laboratory of Neuronal and Glial Physiology, Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neurosciences, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Maria Kukley
- Laboratory of Neuronal and Glial Physiology, Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque - Basque Foundation for Science, Bilbao, Spain
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Recent Insights into the Functional Role of AMPA Receptors in the Oligodendrocyte Lineage Cells In Vivo. Int J Mol Sci 2023; 24:ijms24044138. [PMID: 36835546 PMCID: PMC9967469 DOI: 10.3390/ijms24044138] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
This review discusses the experimental findings of several recent studies which investigated the functional role of AMPA receptors (AMPARs) in oligodendrocyte lineage cells in vivo, in mice and in zebrafish. These studies provided valuable information showing that oligodendroglial AMPARs may be involved in the modulation of proliferation, differentiation, and migration of oligodendroglial progenitors, as well as survival of myelinating oligodendrocytes during physiological conditions in vivo. They also suggested that targeting the subunit composition of AMPARs may be an important strategy for treating diseases. However, at the same time, the experimental findings taken together still do not provide a clear picture on the topic. Hence, new ideas and new experimental designs are required for understanding the functional role of AMPARs in the oligodendrocyte lineage cells in vivo. It is also necessary to consider more closely the temporal and spatial aspects of AMPAR-mediated signalling in the oligodendrocyte lineage cells. These two important aspects are routinely discussed by neuronal physiologists studying glutamatergic synaptic transmission, but are rarely debated and thought about by researchers studying glial cells.
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Faw TD, Lakhani B, Schmalbrock P, Knopp MV, Lohse KR, Kramer JLK, Liu H, Nguyen HT, Phillips EG, Bratasz A, Fisher LC, Deibert RJ, Boyd LA, McTigue DM, Basso DM. Eccentric rehabilitation induces white matter plasticity and sensorimotor recovery in chronic spinal cord injury. Exp Neurol 2021; 346:113853. [PMID: 34464653 PMCID: PMC10084731 DOI: 10.1016/j.expneurol.2021.113853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 08/04/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022]
Abstract
Experience-dependent white matter plasticity offers new potential for rehabilitation-induced recovery after neurotrauma. This first-in-human translational experiment combined myelin water imaging in humans and genetic fate-mapping of oligodendrocyte lineage cells in mice to investigate whether downhill locomotor rehabilitation that emphasizes eccentric muscle actions promotes white matter plasticity and recovery in chronic, incomplete spinal cord injury (SCI). In humans, of 20 individuals with SCI that enrolled, four passed the imaging screen and had myelin water imaging before and after a 12-week (3 times/week) downhill locomotor treadmill training program (SCI + DH). One individual was excluded for imaging artifacts. Uninjured control participants (n = 7) had two myelin water imaging sessions within the same day. Changes in myelin water fraction (MWF), a histopathologically-validated myelin biomarker, were analyzed in a priori motor learning and non-motor learning brain regions and the cervical spinal cord using statistical approaches appropriate for small sample sizes. PDGFRα-CreERT2:mT/mG mice, that express green fluorescent protein on oligodendrocyte precursor cells and subsequent newly-differentiated oligodendrocytes upon tamoxifen-induced recombination, were either naive (n = 6) or received a moderate (75 kilodyne), contusive SCI at T9 and were randomized to downhill training (n = 6) or unexercised groups (n = 6). We initiated recombination 29 days post-injury, seven days prior to downhill training. Mice underwent two weeks of daily downhill training on the same 10% decline grade used in humans. Between-group comparison of functional (motor and sensory) and histological (oligodendrogenesis, oligodendroglial/axon interaction, paranodal structure) outcomes occurred post-training. In humans with SCI, downhill training increased MWF in brain motor learning regions (postcentral, precuneus) and mixed motor and sensory tracts of the ventral cervical spinal cord compared to control participants (P < 0.05). In mice with thoracic SCI, downhill training induced oligodendrogenesis in cervical dorsal and lateral white matter, increased axon-oligodendroglial interactions, and normalized paranodal structure in dorsal column sensory tracts (P < 0.05). Downhill training improved sensorimotor recovery in mice by normalizing hip and knee motor control and reducing hyperalgesia, both of which were associated with new oligodendrocytes in the cervical dorsal columns (P < 0.05). Our findings indicate that eccentric-focused, downhill rehabilitation promotes white matter plasticity and improved function in chronic SCI, likely via oligodendrogenesis in nervous system regions activated by the training paradigm. Together, these data reveal an exciting role for eccentric training in white matter plasticity and sensorimotor recovery after SCI.
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Affiliation(s)
- Timothy D Faw
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; Department of Orthopaedic Surgery, Duke University, Durham, NC 27710, USA
| | - Bimal Lakhani
- Department of Physical Therapy, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Petra Schmalbrock
- Department of Radiology, The Ohio State University, Columbus, OH 43210, USA
| | - Michael V Knopp
- Department of Radiology, The Ohio State University, Columbus, OH 43210, USA
| | - Keith R Lohse
- Department of Health, Kinesiology, and Recreation, University of Utah, Salt Lake City, UT 84112, USA; Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT 84108, USA
| | - John L K Kramer
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC V5Z 1M9, Canada
| | - Hanwen Liu
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC V5Z 1M9, Canada; Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Huyen T Nguyen
- Department of Radiology, The Ohio State University, Columbus, OH 43210, USA
| | - Eileen G Phillips
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Anna Bratasz
- Small Animal Imaging Shared Resources, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Lesley C Fisher
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Rochelle J Deibert
- Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Lara A Boyd
- Department of Physical Therapy, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Dana M McTigue
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; Department of Neuroscience, The Ohio State University, Columbus, OH 43210, USA
| | - D Michele Basso
- Neuroscience Graduate Program, The Ohio State University, Columbus, OH 43210, USA; Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, OH 43210, USA; School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, OH 43210, USA.
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Ion Channels as New Attractive Targets to Improve Re-Myelination Processes in the Brain. Int J Mol Sci 2021; 22:ijms22147277. [PMID: 34298893 PMCID: PMC8305962 DOI: 10.3390/ijms22147277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 12/20/2022] Open
Abstract
Multiple sclerosis (MS) is the most demyelinating disease of the central nervous system (CNS) characterized by neuroinflammation. Oligodendrocyte progenitor cells (OPCs) are cycling cells in the developing and adult CNS that, under demyelinating conditions, migrate to the site of lesions and differentiate into mature oligodendrocytes to remyelinate damaged axons. However, this process fails during disease chronicization due to impaired OPC differentiation. Moreover, OPCs are crucial players in neuro-glial communication as they receive synaptic inputs from neurons and express ion channels and neurotransmitter/neuromodulator receptors that control their maturation. Ion channels are recognized as attractive therapeutic targets, and indeed ligand-gated and voltage-gated channels can both be found among the top five pharmaceutical target groups of FDA-approved agents. Their modulation ameliorates some of the symptoms of MS and improves the outcome of related animal models. However, the exact mechanism of action of ion-channel targeting compounds is often still unclear due to the wide expression of these channels on neurons, glia, and infiltrating immune cells. The present review summarizes recent findings in the field to get further insights into physio-pathophysiological processes and possible therapeutic mechanisms of drug actions.
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Early life adversity targets the transcriptional signature of hippocampal NG2+ glia and affects voltage gated sodium (Na v) channels properties. Neurobiol Stress 2021; 15:100338. [PMID: 34095364 PMCID: PMC8164094 DOI: 10.1016/j.ynstr.2021.100338] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 05/07/2021] [Accepted: 05/08/2021] [Indexed: 12/27/2022] Open
Abstract
The precise mechanisms underlying the detrimental effects of early life adversity (ELA) on adult mental health remain still elusive. To date, most studies have exclusively targeted neuronal populations and not considered neuron-glia crosstalk as a crucially important element for the integrity of stress-related brain function. Here, we have investigated the impact of ELA, in the form of a limited bedding and nesting material (LBN) paradigm, on a glial subpopulation with unique properties in brain homeostasis, the NG2+ cells. First, we have established a link between maternal behavior, activation of the offspring's stress response and heterogeneity in the outcome to LBN manipulation. We further showed that LBN targets the hippocampal NG2+ transcriptome with glucocorticoids being an important mediator of the LBN-induced molecular changes. LBN altered the NG2+ transcriptome and these transcriptional effects were correlated with glucocorticoids levels. The functional relevance of one LBN-induced candidate gene, Scn7a, could be confirmed by an increase in the density of voltage-gated sodium (Nav) channel activated currents in hippocampal NG2+ cells. Scn7a remained upregulated until adulthood in LBN animals, which displayed impaired cognitive performance. Considering that Nav channels are important for NG2+ cell-to-neuron communication, our findings provide novel insights into the disruption of this process in LBN mice.
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12
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Ronzano R, Thetiot M, Lubetzki C, Desmazieres A. Myelin Plasticity and Repair: Neuro-Glial Choir Sets the Tuning. Front Cell Neurosci 2020; 14:42. [PMID: 32180708 PMCID: PMC7059744 DOI: 10.3389/fncel.2020.00042] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 02/12/2020] [Indexed: 12/11/2022] Open
Abstract
The plasticity of the central nervous system (CNS) in response to neuronal activity has been suggested as early as 1894 by Cajal (1894). CNS plasticity has first been studied with a focus on neuronal structures. However, in the last decade, myelin plasticity has been unraveled as an adaptive mechanism of importance, in addition to the previously described processes of myelin repair. Indeed, it is now clear that myelin remodeling occurs along with life and adapts to the activity of neuronal networks. Until now, it has been considered as a two-part dialog between the neuron and the oligodendroglial lineage. However, other glial cell types might be at play in myelin plasticity. In the present review, we first summarize the key structural parameters for myelination, we then describe how neuronal activity modulates myelination and finally discuss how other glial cells could participate in myelinic adaptivity.
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Affiliation(s)
- Remi Ronzano
- Institut du Cerveau et de la Moelle épinière, Sorbonne Universités UPMC Université Paris 06, CNRS UMR7225-Inserm U1127, Paris, France
| | - Melina Thetiot
- Institut du Cerveau et de la Moelle épinière, Sorbonne Universités UPMC Université Paris 06, CNRS UMR7225-Inserm U1127, Paris, France
- Unit Zebrafish Neurogenetics, Department of Developmental & Stem Cell Biology, Institut Pasteur, CNRS, Paris, France
| | - Catherine Lubetzki
- Institut du Cerveau et de la Moelle épinière, Sorbonne Universités UPMC Université Paris 06, CNRS UMR7225-Inserm U1127, Paris, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Paris, France
| | - Anne Desmazieres
- Institut du Cerveau et de la Moelle épinière, Sorbonne Universités UPMC Université Paris 06, CNRS UMR7225-Inserm U1127, Paris, France
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13
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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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14
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Extrinsic Factors Driving Oligodendrocyte Lineage Cell Progression in CNS Development and Injury. Neurochem Res 2020; 45:630-642. [PMID: 31997102 PMCID: PMC7058689 DOI: 10.1007/s11064-020-02967-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/19/2019] [Accepted: 12/21/2019] [Indexed: 12/15/2022]
Abstract
Oligodendrocytes (OLs) generate myelin membranes for the rapid propagation of electrical signals along axons in the central nervous system (CNS) and provide metabolites to support axonal integrity and function. Differentiation of OLs from oligodendrocyte progenitor cells (OPCs) is orchestrated by a multitude of intrinsic and extrinsic factors in the CNS. Disruption of this process, or OL loss in the developing or adult brain, as observed in various neurological conditions including hypoxia/ischemia, stroke, and demyelination, results in axonal dystrophy, neuronal dysfunction, and severe neurological impairments. While much is known regarding the intrinsic regulatory signals required for OL lineage cell progression in development, studies from pathological conditions highlight the importance of the CNS environment and external signals in regulating OL genesis and maturation. Here, we review the recent findings in OL biology in the context of the CNS physiological and pathological conditions, focusing on extrinsic factors that facilitate OL development and regeneration.
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15
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Abstract
In the peripheral nervous system, the vast majority of axons are accommodated within the fibre bundles that constitute the peripheral nerves. Axons within the nerves are in close contact with myelinating glia, the Schwann cells that are ideally placed to respond to, and possibly shape, axonal activity. The mechanisms of intercellular communication in the peripheral nerves may involve direct contact between the cells, as well as signalling via diffusible substances. Neurotransmitter glutamate has been proposed as a candidate extracellular molecule mediating the cross-talk between cells in the peripheral nerves. Two types of experimental findings support this idea: first, glutamate has been detected in the nerves and can be released upon electrical or chemical stimulation of the nerves; second, axons and Schwann cells in the peripheral nerves express glutamate receptors. Yet, the studies providing direct experimental evidence that intercellular glutamatergic signalling takes place in the peripheral nerves during physiological or pathological conditions are largely missing. Remarkably, in the central nervous system, axons and myelinating glia are involved in glutamatergic signalling. This signalling occurs via different mechanisms, the most intriguing of which is fast synaptic communication between axons and oligodendrocyte precursor cells. Glutamate receptors and/or synaptic axon-glia signalling are involved in regulation of proliferation, migration, and differentiation of oligodendrocyte precursor cells, survival of oligodendrocytes, and re-myelination of axons after damage. Does synaptic signalling exist between axons and Schwann cells in the peripheral nerves? What is the functional role of glutamate receptors in the peripheral nerves? Is activation of glutamate receptors in the nerves beneficial or harmful during diseases? In this review, we summarise the limited information regarding glutamate release and glutamate receptors in the peripheral nerves and speculate about possible mechanisms of glutamatergic signalling in the nerves. We highlight the necessity of further research on this topic because it should help to understand the mechanisms of peripheral nervous system development and nerve regeneration during diseases.
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Affiliation(s)
- Ting-Jiun Chen
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Centre, Washington, DC, USA
| | - Maria Kukley
- Group of Neuron Glia Interaction, University of Tübingen; Research Institute of Ophthalmology, Tübingen University Hospital, Tübingen, Germany
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16
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Chen TJ, Kula B, Nagy B, Barzan R, Gall A, Ehrlich I, Kukley M. In Vivo Regulation of Oligodendrocyte Precursor Cell Proliferation and Differentiation by the AMPA-Receptor Subunit GluA2. Cell Rep 2019; 25:852-861.e7. [PMID: 30355492 DOI: 10.1016/j.celrep.2018.09.066] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 08/09/2018] [Accepted: 09/19/2018] [Indexed: 01/01/2023] Open
Abstract
The functional role of AMPA receptor (AMPAR)-mediated synaptic signaling between neurons and oligodendrocyte precursor cells (OPCs) remains enigmatic. We modified the properties of AMPARs at axon-OPC synapses in the mouse corpus callosum in vivo during the peak of myelination by targeting the GluA2 subunit. Expression of the unedited (Ca2+ permeable) or the pore-dead GluA2 subunit of AMPARs triggered proliferation of OPCs and reduced their differentiation into oligodendrocytes. Expression of the cytoplasmic C-terminal (GluA2(813-862)) of the GluA2 subunit (C-tail), a modification designed to affect the interaction between GluA2 and AMPAR-binding proteins and to perturb trafficking of GluA2-containing AMPARs, decreased the differentiation of OPCs without affecting their proliferation. These findings suggest that ionotropic and non-ionotropic properties of AMPARs in OPCs, as well as specific aspects of AMPAR-mediated signaling at axon-OPC synapses in the mouse corpus callosum, are important for balancing the response of OPCs to proliferation and differentiation cues.
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Affiliation(s)
- Ting-Jiun Chen
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Graduate Training Centre of Neuroscience, University of Tübingen, 72074 Tübingen, Germany
| | - Bartosz Kula
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Graduate Training Centre of Neuroscience, University of Tübingen, 72074 Tübingen, Germany
| | - Bálint Nagy
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Graduate Training Centre of Neuroscience, University of Tübingen, 72074 Tübingen, Germany; Institute of Science and Technology (IST) Austria, 3400 Klosterneuburg, Austria
| | - Ruxandra Barzan
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Graduate Training Centre of Neuroscience, University of Tübingen, 72074 Tübingen, Germany
| | - Andrea Gall
- Learning and Memory Group, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Learning and Memory Group, Hertie Institute for Brain Research, University of Tübingen, 72076 Tübingen, Germany; Department of Neurobiology, IBBS, University of Stuttgart, 70569 Stuttgart, Germany
| | - Ingrid Ehrlich
- Learning and Memory Group, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Learning and Memory Group, Hertie Institute for Brain Research, University of Tübingen, 72076 Tübingen, Germany; Department of Neurobiology, IBBS, University of Stuttgart, 70569 Stuttgart, Germany
| | - Maria Kukley
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany; Department of Ophthalmology, Research Institute of Ophthalmology, Faculty of Medicine, University Hospital Tübingen, 72076 Tübingen, Germany.
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17
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Duncan GJ, Manesh SB, Hilton BJ, Assinck P, Plemel JR, Tetzlaff W. The fate and function of oligodendrocyte progenitor cells after traumatic spinal cord injury. Glia 2019; 68:227-245. [PMID: 31433109 DOI: 10.1002/glia.23706] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 07/24/2019] [Accepted: 08/01/2019] [Indexed: 12/27/2022]
Abstract
Oligodendrocyte progenitor cells (OPCs) are the most proliferative and dispersed population of progenitor cells in the adult central nervous system, which allows these cells to rapidly respond to damage. Oligodendrocytes and myelin are lost after traumatic spinal cord injury (SCI), compromising efficient conduction and, potentially, the long-term health of axons. In response, OPCs proliferate and then differentiate into new oligodendrocytes and Schwann cells to remyelinate axons. This culminates in highly efficient remyelination following experimental SCI in which nearly all intact demyelinated axons are remyelinated in rodent models. However, myelin regeneration comprises only one role of OPCs following SCI. OPCs contribute to scar formation after SCI and restrict the regeneration of injured axons. Moreover, OPCs alter their gene expression following demyelination, express cytokines and perpetuate the immune response. Here, we review the functional contribution of myelin regeneration and other recently uncovered roles of OPCs and their progeny to repair following SCI.
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Affiliation(s)
- Greg J Duncan
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health and Science University, Portland, Oregon
| | - Sohrab B Manesh
- Graduate Program in Neuroscience, International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), Vancouver, British Columbia, Canada
| | - Brett J Hilton
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Bonn, Germany
| | - Peggy Assinck
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK
| | - Jason R Plemel
- Department of Medicine, Division of Neurology, Neuroscience and Mental Health Institute, University of Alberta, Calgary, Alberta, Canada
| | - Wolfram Tetzlaff
- Graduate Program in Neuroscience, International Collaboration on Repair Discoveries (ICORD), University of British Columbia (UBC), Vancouver, British Columbia, Canada.,Departments of Zoology and Surgery, University of British Columbia, Vancouver, British Columbia, Canada
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18
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Ceprian M, Fulton D. Glial Cell AMPA Receptors in Nervous System Health, Injury and Disease. Int J Mol Sci 2019; 20:E2450. [PMID: 31108947 PMCID: PMC6566241 DOI: 10.3390/ijms20102450] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/11/2019] [Accepted: 04/22/2019] [Indexed: 12/16/2022] Open
Abstract
Glia form a central component of the nervous system whose varied activities sustain an environment that is optimised for healthy development and neuronal function. Alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA)-type glutamate receptors (AMPAR) are a central mediator of glutamatergic excitatory synaptic transmission, yet they are also expressed in a wide range of glial cells where they influence a variety of important cellular functions. AMPAR enable glial cells to sense the activity of neighbouring axons and synapses, and as such many aspects of glial cell development and function are influenced by the activity of neural circuits. However, these AMPAR also render glia sensitive to elevations of the extracellular concentration of glutamate, which are associated with a broad range of pathological conditions. Excessive activation of AMPAR under these conditions may induce excitotoxic injury in glial cells, and trigger pathophysiological responses threatening other neural cells and amplifying ongoing disease processes. The aim of this review is to gather information on AMPAR function from across the broad diversity of glial cells, identify their contribution to pathophysiological processes, and highlight new areas of research whose progress may increase our understanding of nervous system dysfunction and disease.
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Affiliation(s)
- Maria Ceprian
- Instituto de Investigación Sanitaria San Carlos (IdISSC), 28040 Madrid, Spain.
- Departamento de Bioquímica y Biología Molecular, CIBERNED, IRICYS. Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Daniel Fulton
- Neuroscience and Ophthalmology Research Group, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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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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Fontenas L, Welsh TG, Piller M, Coughenour P, Gandhi AV, Prober DA, Kucenas S. The Neuromodulator Adenosine Regulates Oligodendrocyte Migration at Motor Exit Point Transition Zones. Cell Rep 2019; 27:115-128.e5. [PMID: 30943395 PMCID: PMC6461400 DOI: 10.1016/j.celrep.2019.03.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 01/27/2019] [Accepted: 03/02/2019] [Indexed: 12/30/2022] Open
Abstract
During development, oligodendrocyte progenitor cells (OPCs) migrate extensively throughout the spinal cord. However, their migration is restricted at transition zones (TZs). At these specialized locations, unique glial cells in both zebrafish and mice play a role in preventing peripheral OPC migration, but the mechanisms of this regulation are not understood. To elucidate the mechanisms that mediate OPC segregation at motor exit point (MEP) TZs, we performed an unbiased small-molecule screen. Using chemical screening and in vivo imaging, we discovered that inhibition of A2a adenosine receptors (ARs) causes ectopic OPC migration out of the spinal cord. We provide in vivo evidence that neuromodulation, partially mediated by adenosine, influences OPC migration specifically at the MEP TZ. This work opens exciting possibilities for understanding how OPCs reach their final destinations during development and identifies mechanisms that could promote their migration in disease.
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Affiliation(s)
- Laura Fontenas
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Taylor G Welsh
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22904, USA
| | - Melanie Piller
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Patricia Coughenour
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA
| | - Avni V Gandhi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - David A Prober
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sarah Kucenas
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22904, USA.
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21
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Abstract
Oligodendrocyte form myelin around the axons to regulate the conduction velocity. Myelinated axons are composed of white matter to act as cables to connect distinct brain regions. Recent human MRI studies showed that the signal from white matter change in the people with special skills such as taxi driver, piano player, and juggling. The change of the white matter suggested that (1) The plasticity of myelination depends on neuronal activity (activity-dependent myelination) and (2) White matter plasticity is essential for brain functions. In this session, we discussed that how the un-electrical components, oligodendrocytes, and its precursor cells receive the signal from electrically active neurons and differentiate, proliferate, and myelinate the axons to modulate the activity of neuronal circuits, ultimately affect on their behaviors. In this review, we highlight the physiological functions of oligodendrocyte and their neuronal activity-dependent functions and thus show new insight for their contribution to brain functions.
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22
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Tran AP, Warren PM, Silver J. The Biology of Regeneration Failure and Success After Spinal Cord Injury. Physiol Rev 2018. [PMID: 29513146 DOI: 10.1152/physrev.00017.2017] [Citation(s) in RCA: 490] [Impact Index Per Article: 81.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Since no approved therapies to restore mobility and sensation following spinal cord injury (SCI) currently exist, a better understanding of the cellular and molecular mechanisms following SCI that compromise regeneration or neuroplasticity is needed to develop new strategies to promote axonal regrowth and restore function. Physical trauma to the spinal cord results in vascular disruption that, in turn, causes blood-spinal cord barrier rupture leading to hemorrhage and ischemia, followed by rampant local cell death. As subsequent edema and inflammation occur, neuronal and glial necrosis and apoptosis spread well beyond the initial site of impact, ultimately resolving into a cavity surrounded by glial/fibrotic scarring. The glial scar, which stabilizes the spread of secondary injury, also acts as a chronic, physical, and chemo-entrapping barrier that prevents axonal regeneration. Understanding the formative events in glial scarring helps guide strategies towards the development of potential therapies to enhance axon regeneration and functional recovery at both acute and chronic stages following SCI. This review will also discuss the perineuronal net and how chondroitin sulfate proteoglycans (CSPGs) deposited in both the glial scar and net impede axonal outgrowth at the level of the growth cone. We will end the review with a summary of current CSPG-targeting strategies that help to foster axonal regeneration, neuroplasticity/sprouting, and functional recovery following SCI.
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Affiliation(s)
- Amanda Phuong Tran
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
| | - Philippa Mary Warren
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
| | - Jerry Silver
- Department of Neurosciences, Case Western Reserve University , Cleveland, Ohio ; and School of Biomedical Sciences, University of Leeds , Leeds , United Kingdom
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23
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Hanganu A, Houde JC, Fonov VS, Degroot C, Mejia-Constain B, Lafontaine AL, Soland V, Chouinard S, Collins LD, Descoteaux M, Monchi O. White matter degeneration profile in the cognitive cortico-subcortical tracts in Parkinson's disease. Mov Disord 2018; 33:1139-1150. [PMID: 29683523 DOI: 10.1002/mds.27364] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 01/22/2018] [Accepted: 01/24/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND In Parkinson's disease cognitive impairment is an early nonmotor feature, but it is still unclear why some patients are able to maintain their cognitive performance at normal levels, as quantified by neuropsychological tests, whereas others cannot. The objectives of this study were to perform a cross-sectional study and analyze the white matter changes in the cognitive and motor bundles in patients with Parkinson's disease. METHODS Sixteen Parkinson's disease patients with normal cognitive performance, 19 with mild cognitive impairment (based on their performance of 1.5 standard deviations below the healthy population mean), and 16 healthy controls were compared with respect to their tractography patterns between the cortical cognitive / motor regions and subcortical structures, using high angular resolution diffusion imaging and constrained spherical deconvolution computation. RESULTS Motor bundles showed decreased apparent fiber density in both PD groups, associated with a significant increase in diffusivity metrics, number of reconstructed streamlines, and track volumes, compared with healthy controls. By contrast, in the cognitive bundles, decreased fiber density in both Parkinson's groups was compounded by the absence of changes in diffusivity in patients with normal cognition, whereas patients with cognitive impairment had increased diffusivity metrics, lower numbers of reconstructed streamlines, and lower track volumes. CONCLUSIONS Both PD groups showed similar patterns of white matter neurodegeneration in the motor bundles, whereas cognitive bundles showed a distinct pattern: Parkinson's patients with normal cognition had white matter diffusivity metrics similar to healthy controls, whereas in patients with cognitive impairment white matter showed a neurodegeneration pattern. © 2018 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Alexandru Hanganu
- Department of Clinical Neurosciences and Department of Radiology, University of Calgary, Calgary, Alberta, Canada.,Cumming School of Medicine, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Jean-Christophe Houde
- Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science Department, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Vladimir S Fonov
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montréal, Quebec, Canada
| | - Clotilde Degroot
- Centre de Recherche, Institut Universitaire de Gériatrie de Montréal, Montréal, Quebec, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Quebec, Canada
| | - Beatriz Mejia-Constain
- Centre de Recherche, Institut Universitaire de Gériatrie de Montréal, Montréal, Quebec, Canada
| | - Anne-Louise Lafontaine
- Department of Neurology and Neurosurgery, McGill University, Montréal, Quebec, Canada.,Movement Disorders Unit, McGill University Health Center, Montréal, Quebec, Canada
| | - Valérie Soland
- Unité des Troubles du Mouvement André Barbeau, Centre Hospitalier de l'Université de Montréal, Montréal, Quebec, Canada
| | - Sylvain Chouinard
- Unité des Troubles du Mouvement André Barbeau, Centre Hospitalier de l'Université de Montréal, Montréal, Quebec, Canada
| | - Louis D Collins
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montréal, Quebec, Canada
| | - Maxime Descoteaux
- Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science Department, Université de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Oury Monchi
- Department of Clinical Neurosciences and Department of Radiology, University of Calgary, Calgary, Alberta, Canada.,Cumming School of Medicine, Hotchkiss Brain Institute, Calgary, Alberta, Canada.,Centre de Recherche, Institut Universitaire de Gériatrie de Montréal, Montréal, Quebec, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Quebec, Canada.,Department of Radiology, Faculty of Medicine, University of Montréal, Montréal, Quebec, Canada
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24
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Osterstock G, Le Bras B, Arulkandarajah KH, Le Corronc H, Czarnecki A, Mouffle C, Bullier E, Legendre P, Mangin JM. Axoglial synapses are formed onto pioneer oligodendrocyte precursor cells at the onset of spinal cord gliogenesis. Glia 2018; 66:1678-1694. [PMID: 29603384 DOI: 10.1002/glia.23331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 03/05/2018] [Accepted: 03/05/2018] [Indexed: 12/12/2022]
Abstract
Virtually all oligodendrocyte precursors cells (OPCs) receive glutamatergic and/or GABAergic synapses that are lost upon their differentiation into oligodendrocytes in the postnatal and adult brain. Although OPCs are generated at mid-embryonic stages, several weeks before the onset of myelination, it remains unknown when and where OPCs receive their first synapses and become susceptible to the influence of neuronal activity. In the embryonic spinal cord, neuro-epithelial precursors in the pMN domain cease generating cholinergic motor neurons (MNs) to produce OPCs when the first synapses are formed in the ventral-lateral marginal zone. We discovered that when the first synapses form onto MNs, axoglial synapses also form onto the processes of neuro-epithelial precursors located in the marginal zone as they differentiate into OPCs. After leaving the neuro-epithelium, these pioneer OPCs preferentially accumulate in the marginal zone where they are contacted by functional glutamatergic and GABAergic synapses. Spontaneous activity of these axoglial synapses was significantly potentiated by cholinergic signaling acting through presynaptic nicotinic acetylcholine receptors. Moreover, we discovered that chronic nicotine treatment significantly increases early OPC proliferation and density in the marginal zone. Our results demonstrate that OPCs are contacted by functional synapses as soon as they emerge from their precursor domain and that embryonic spinal cord colonization by OPCs can be regulated by cholinergic signaling acting onto these axoglial synapses.
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Affiliation(s)
- Guillaume Osterstock
- Sorbonne Université, UM119, Neuroscience Paris Seine, Paris F-75005, France Centre National de la Recherche Scientifique (CNRS), UMR 8246, Paris F-75005, France Institut National de la Santé et de la Recherche Médicale (INSERM), U1130, Paris, F-75005, France
| | - Barbara Le Bras
- Sorbonne Université, UM119, Neuroscience Paris Seine, Paris F-75005, France Centre National de la Recherche Scientifique (CNRS), UMR 8246, Paris F-75005, France Institut National de la Santé et de la Recherche Médicale (INSERM), U1130, Paris, F-75005, France
| | - Kalaimakan Hervé Arulkandarajah
- Sorbonne Université, UM119, Neuroscience Paris Seine, Paris F-75005, France Centre National de la Recherche Scientifique (CNRS), UMR 8246, Paris F-75005, France Institut National de la Santé et de la Recherche Médicale (INSERM), U1130, Paris, F-75005, France
| | - Hervé Le Corronc
- Sorbonne Université, UM119, Neuroscience Paris Seine, Paris F-75005, France Centre National de la Recherche Scientifique (CNRS), UMR 8246, Paris F-75005, France Institut National de la Santé et de la Recherche Médicale (INSERM), U1130, Paris, F-75005, France.,Université d'Angers, Angers, 49000, France
| | - Antonny Czarnecki
- Sorbonne Université, UM119, Neuroscience Paris Seine, Paris F-75005, France Centre National de la Recherche Scientifique (CNRS), UMR 8246, Paris F-75005, France Institut National de la Santé et de la Recherche Médicale (INSERM), U1130, Paris, F-75005, France
| | - Christine Mouffle
- Sorbonne Université, UM119, Neuroscience Paris Seine, Paris F-75005, France Centre National de la Recherche Scientifique (CNRS), UMR 8246, Paris F-75005, France Institut National de la Santé et de la Recherche Médicale (INSERM), U1130, Paris, F-75005, France
| | - Erika Bullier
- Sorbonne Université, UM119, Neuroscience Paris Seine, Paris F-75005, France Centre National de la Recherche Scientifique (CNRS), UMR 8246, Paris F-75005, France Institut National de la Santé et de la Recherche Médicale (INSERM), U1130, Paris, F-75005, France
| | - Pascal Legendre
- Sorbonne Université, UM119, Neuroscience Paris Seine, Paris F-75005, France Centre National de la Recherche Scientifique (CNRS), UMR 8246, Paris F-75005, France Institut National de la Santé et de la Recherche Médicale (INSERM), U1130, Paris, F-75005, France
| | - Jean-Marie Mangin
- Sorbonne Université, UM119, Neuroscience Paris Seine, Paris F-75005, France Centre National de la Recherche Scientifique (CNRS), UMR 8246, Paris F-75005, France Institut National de la Santé et de la Recherche Médicale (INSERM), U1130, Paris, F-75005, France
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25
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Welsh TG, Kucenas S. Purinergic signaling in oligodendrocyte development and function. J Neurochem 2018; 145:6-18. [PMID: 29377124 DOI: 10.1111/jnc.14315] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/08/2018] [Accepted: 01/21/2018] [Indexed: 12/31/2022]
Abstract
Myelin, an insulating membrane that enables rapid action potential propagation, is an essential component of an efficient, functional vertebrate nervous system. Oligodendrocytes, the myelinating glia of the central nervous system (CNS), produce myelin throughout the CNS, which requires continuous proliferation, migration, and differentiation of oligodendrocyte progenitor cells. Because myelination is essential for efficient neurotransmission, researchers hypothesize that neuronal signals may regulate the cascade of events necessary for this process. The ability of oligodendrocytes and oligodendrocyte progenitor cells to detect and respond to neuronal activity is becoming increasingly appreciated, although the specific signals involved are still a matter of debate. Recent evidence from multiple studies points to purinergic signaling as a potential regulator of oligodendrocyte development and differentiation. Adenosine triphosphate (ATP) and its derivatives are potent signaling ligands with receptors expressed on many populations of cells in the nervous system, including cells of the oligodendrocyte lineage. Release of ATP into the extracellular space can initiate a multitude of signaling events, and these downstream signals are specific to the particular purinergic receptor (or receptors) expressed, and whether enzymes are present to hydrolyze ATP to its derivatives adenosine diphosphate and adenosine, each of which can activate their own unique downstream signaling cascades. This review will introduce purinergic signaling in the CNS and discuss evidence for its effects on oligodendrocyte proliferation, differentiation, and myelination. We will review sources of extracellular purines in the nervous system and how changes in purinergic receptor expression may be coupled to oligodendrocyte differentiation. We will also briefly discuss purinergic signaling in injury and diseases of the CNS.
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Affiliation(s)
- Taylor G Welsh
- Neuroscience Graduate Program, Charlottesville, Virginia, USA
| | - Sarah Kucenas
- Neuroscience Graduate Program, Charlottesville, Virginia, USA.,Department of Biology, University of Virginia, Charlottesville, Virginia, USA
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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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Baxi EG, DeBruin J, Jin J, Strasburger HJ, Smith MD, Orthmann-Murphy JL, Schott JT, Fairchild AN, Bergles DE, Calabresi PA. Lineage tracing reveals dynamic changes in oligodendrocyte precursor cells following cuprizone-induced demyelination. Glia 2017; 65:2087-2098. [PMID: 28940645 DOI: 10.1002/glia.23229] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 08/20/2017] [Accepted: 08/23/2017] [Indexed: 11/10/2022]
Abstract
The regeneration of oligodendrocytes is a crucial step in recovery from demyelination, as surviving oligodendrocytes exhibit limited structural plasticity and rarely form additional myelin sheaths. New oligodendrocytes arise through the differentiation of platelet-derived growth factor receptor α (PDGFRα) expressing oligodendrocyte progenitor cells (OPCs) that are widely distributed throughout the CNS. Although there has been detailed investigation of the behavior of these progenitors in white matter, recent studies suggest that disease burden in multiple sclerosis (MS) is more strongly correlated with gray matter atrophy. The timing and efficiency of remyelination in gray matter is distinct from white matter, but the dynamics of OPCs that contribute to these differences have not been defined. Here, we used in vivo genetic fate tracing to determine the behavior of OPCs in gray and white matter regions in response to cuprizone-induced demyelination. Our studies indicate that the temporal dynamics of OPC differentiation varies significantly between white and gray matter. While OPCs rapidly repopulate the corpus callosum and mature into CC1 expressing mature oligodendrocytes, OPC differentiation in the cingulate cortex and hippocampus occurs much more slowly, resulting in a delay in remyelination relative to the corpus callosum. The protracted maturation of OPCs in gray matter may contribute to greater axonal pathology and disease burden in MS.
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Affiliation(s)
- Emily G Baxi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Joseph DeBruin
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jing Jin
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hayley J Strasburger
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Matthew D Smith
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jennifer L Orthmann-Murphy
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University Medical School, Baltimore, Maryland
| | - Jason T Schott
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Amanda N Fairchild
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University Medical School, Baltimore, Maryland
| | - Peter A Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University Medical School, Baltimore, Maryland
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Nagy B, Hovhannisyan A, Barzan R, Chen TJ, Kukley M. Different patterns of neuronal activity trigger distinct responses of oligodendrocyte precursor cells in the corpus callosum. PLoS Biol 2017; 15:e2001993. [PMID: 28829781 PMCID: PMC5567905 DOI: 10.1371/journal.pbio.2001993] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 07/18/2017] [Indexed: 12/28/2022] Open
Abstract
In the developing and adult brain, oligodendrocyte precursor cells (OPCs) are influenced by neuronal activity: they are involved in synaptic signaling with neurons, and their proliferation and differentiation into myelinating glia can be altered by transient changes in neuronal firing. An important question that has been unanswered is whether OPCs can discriminate different patterns of neuronal activity and respond to them in a distinct way. Here, we demonstrate in brain slices that the pattern of neuronal activity determines the functional changes triggered at synapses between axons and OPCs. Furthermore, we show that stimulation of the corpus callosum at different frequencies in vivo affects proliferation and differentiation of OPCs in a dissimilar way. Our findings suggest that neurons do not influence OPCs in “all-or-none” fashion but use their firing pattern to tune the response and behavior of these nonneuronal cells. Oligodendrocytes are glial cells of the central nervous system. One of their major tasks is to enwrap neuronal axons with myelin, providing electrical insulation of axons and a dramatic increase in the speed of nerve impulse propagation. Oligodendrocytes develop from oligodendrocyte precursor cells (OPCs). Self-renewal of OPCs, their differentiation into oligodendrocytes, and the process of myelin synthesis are influenced by neuronal activity. Furthermore, OPCs receive glutamatergic synaptic input from neurons. Neuronal activity in vivo is highly variable depending on the brain region, input stimulus, and/or behavioral task that an animal or human has to perform in everyday life. Therefore, it is important to understand whether different types of neuronal activity affect development and function of oligodendrocyte lineage cells in a distinct way. In this study, we demonstrate that the amount and the timing of glutamate release at synapses between neurons and OPCs, the properties of the subsequent ionic current through glutamate receptors in OPC membrane, as well as the extent of OPCs’ self-renewal and differentiation into oligodendrocytes differ depending on the frequency and duration of neuronal activity. Hence, the pattern of neuronal activity rather than just presence or absence of activity is an important parameter that determines development and function of oligodendroglial cells.
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Affiliation(s)
- Balint Nagy
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
- * E-mail: (MK); (BN)
| | - Anahit Hovhannisyan
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Ruxandra Barzan
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Ting-Jiun Chen
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, Tübingen, Germany
| | - Maria Kukley
- Group of Neuron Glia Interaction, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- * E-mail: (MK); (BN)
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Boulanger JJ, Messier C. Oligodendrocyte progenitor cells are paired with GABA neurons in the mouse dorsal cortex: Unbiased stereological analysis. Neuroscience 2017; 362:127-140. [PMID: 28827179 DOI: 10.1016/j.neuroscience.2017.08.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 11/17/2022]
Abstract
Oligodendrocyte progenitor cells (OPC) are glial cells that differentiate into myelinating oligodendrocytes during early stages of post-natal life. However, OPCs persist beyond developmental myelination and represent an important population of cycling cells in the gray and white matter of the adult brain. While adult OPCs form unique territories that are maintained through self-avoidance, some cortical OPCs appear to position their cell body very close to that of a neuron, forming what are known as OPC-neuron pairs. We used unbiased systematic stereological analysis of the NG2-CreERTM:EYFP reporter mouse to determine that close to 170,000 OPC-neuron pairs can be found in the dorsal portion of the adult neocortex, with approximately 40% of OPCs and 4% of neurons in pairs. Through stereological analysis, we also determined that reference memory training does not change the prevalence of OPC-neuron pairs or the proportion of OPCs and neurons that form them. GABAergic agent administration did not affect the proportion of OPCs and neurons that can be found in pairs. However, the GABAB-receptor agonist baclofen and the GABAA receptor antagonist picrotoxin significantly increased the estimated number of pairs when compared to the control group and the GABAB-receptor antagonist (i.e. saclofen) group. Density of OPC-neuron pairs was increased by the GABAA receptor antagonist picrotoxin. Finally, histological analysis of OPC-neuron pairs suggested that in the dorsal portion of the cortex, GABAergic interneurons represent the most common neuronal component of the pairs, and that calbindin, calretinin and parvalbumin GABAergic interneurons found in the cortex take part in these pairs. Using previous estimates of the number of GABAergic neurons in the rodent cortex, we estimate that roughly one in four GABAergic neurons are paired with an OPC.
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Conditional Deletion of the L-Type Calcium Channel Cav1.2 in Oligodendrocyte Progenitor Cells Affects Postnatal Myelination in Mice. J Neurosci 2017; 36:10853-10869. [PMID: 27798140 DOI: 10.1523/jneurosci.1770-16.2016] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 09/03/2016] [Indexed: 12/12/2022] Open
Abstract
To determine whether L-type voltage-operated Ca2+ channels (L-VOCCs) are required for oligodendrocyte progenitor cell (OPC) development, we generated an inducible conditional knock-out mouse in which the L-VOCC isoform Cav1.2 was postnatally deleted in NG2-positive OPCs. A significant hypomyelination was found in the brains of the Cav1.2 conditional knock-out (Cav1.2KO) mice specifically when the Cav1.2 deletion was induced in OPCs during the first 2 postnatal weeks. A decrease in myelin proteins expression was visible in several brain structures, including the corpus callosum, cortex, and striatum, and the corpus callosum of Cav1.2KO animals showed an important decrease in the percentage of myelinated axons and a substantial increase in the mean g-ratio of myelinated axons. The reduced myelination was accompanied by an important decline in the number of myelinating oligodendrocytes and in the rate of OPC proliferation. Furthermore, using a triple transgenic mouse in which all of the Cav1.2KO OPCs were tracked by a Cre reporter, we found that Cav1.2KO OPCs produce less mature oligodendrocytes than control cells. Finally, live-cell imaging in early postnatal brain slices revealed that the migration and proliferation of subventricular zone OPCs is decreased in the Cav1.2KO mice. These results indicate that the L-VOCC isoform Cav1.2 modulates oligodendrocyte development and suggest that Ca2+ influx mediated by L-VOCCs in OPCs is necessary for normal myelination. SIGNIFICANCE STATEMENT Overall, it is clear that cells in the oligodendrocyte lineage exhibit remarkable plasticity with regard to the expression of Ca2+ channels and that perturbation of Ca2+ homeostasis likely plays an important role in the pathogenesis underlying demyelinating diseases. To determine whether voltage-gated Ca2+ entry is involved in oligodendrocyte maturation and myelination, we used a conditional knock-out mouse for voltage-operated Ca2+ channels in oligodendrocyte progenitor cells. Our results indicate that voltage-operated Ca2+ channels can modulate oligodendrocyte development in the postnatal brain and suggest that voltage-gated Ca2+ influx in oligodendroglial cells is critical for normal myelination. These findings could lead to novel approaches to intervene in neurodegenerative diseases in which myelin is lost or damaged.
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Boulanger JJ, Messier C. Unbiased stereological analysis of the fate of oligodendrocyte progenitor cells in the adult mouse brain and effect of reference memory training. Behav Brain Res 2017; 329:127-139. [PMID: 28442356 DOI: 10.1016/j.bbr.2017.04.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 04/12/2017] [Accepted: 04/13/2017] [Indexed: 11/20/2022]
Abstract
Oligodendrocyte progenitor cells (OPCs) are glial cells that differentiate into myelinating oligodendrocytes during early stages of post-natal life. However, OPCs persist beyond developmental myelination and represent an important population of cycling cells in the gray and white matter of the adult brain. Here, we used unbiased systematic stereological analysis to determine the total number of OPCs in the neocortex and corpus callosum of the adult mouse. We found that the ratio of OPCs to neurons is of 1:10 in the adult neocortex. Likewise, the ratio of OPCs to oligodendrocytes is of 1:1 in the cortex and 1:7 in the corpus callosum. We also used BrdU labeling and the NG2-CreER™:EYFP reporter mouse to determine the proportion of proliferating adult OPCs and their fate. We show that OPCs continue to differentiate into oligodendrocytes in adulthood, with white matter OPCs being more likely to differentiate into an oligodendrocyte phenotype than gray matter OPCs. The differentiation of OPCs into an oligodendrocyte phenotype can occur either directly from a spontaneous differentiation by an OPC or following OPC cell division. We also provide evidence for the neuronal differentiation of adult OPCs in the cortical gray matter. Although activity-dependent neural network activity has been hypothesized to serve as a modulator of OPC proliferation and differentiation, we found that reference memory training did not affect the proportion of proliferating and differentiated OPCs in the adult mouse brain.
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Boulanger JJ, Messier C. Doublecortin in Oligodendrocyte Precursor Cells in the Adult Mouse Brain. Front Neurosci 2017; 11:143. [PMID: 28400715 PMCID: PMC5368229 DOI: 10.3389/fnins.2017.00143] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 03/07/2017] [Indexed: 12/21/2022] Open
Abstract
Key PointsOligodendrocyte precursor cells express doublecortin, a microtubule-associated protein. Oligodendrocyte precursor cells express doublecortin, but at a lower level of expression than in neuronal precursor. Doublecortin is not associated with a potential immature neuronal phenotype in Oligodendrocyte precursor cells.
Oligodendrocyte precursor cells (OPC) are glial cells that differentiate into myelinating oligodendrocytes during embryogenesis and early stages of post-natal life. OPCs continue to divide throughout adulthood and some eventually differentiate into oligodendrocytes in response to demyelinating lesions. There is growing evidence that OPCs are also involved in activity-driven de novo myelination of previously unmyelinated axons and myelin remodeling in adulthood. Considering these roles in the adult brain, OPCs are likely mobile cells that can migrate on some distances before they differentiate into myelinating oligodendrocytes. A number of studies have noted that OPCs express doublecortin (DCX), a microtubule-associated protein expressed in neural precursor cells and in migrating immature neurons. Here we describe the distribution of DCX in OPCs. We found that almost all OPCs express DCX, but the level of expression appears to be much lower than what is found in neural precursor. We found that DCX is downregulated when OPCs start expressing mature oligodendrocyte markers and is absent in myelinating oligodendrocytes. DCX does not appear to signal an immature neuronal phenotype in OPCs in the adult mouse brain. Rather, it could be involved either in cell migration, or as a marker of an immature oligodendroglial cell phenotype.
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Affiliation(s)
| | - Claude Messier
- School of Psychology, University of Ottawa Ottawa, ON, Canada
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Takase H, Washida K, Hayakawa K, Arai K, Wang X, Lo EH, Lok J. Oligodendrogenesis after traumatic brain injury. Behav Brain Res 2016; 340:205-211. [PMID: 27829126 DOI: 10.1016/j.bbr.2016.10.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 10/20/2016] [Accepted: 10/21/2016] [Indexed: 01/14/2023]
Abstract
White matter injury is an important contributor to long term motor and cognitive dysfunction after traumatic brain injury. During brain trauma, acceleration, deceleration, torsion, and compression forces often cause direct damage to the axon tracts, and pathways that are triggered by the initial injury can trigger molecular events that result in secondary axon degeneration. White matter injury is often associated with altered mental status, memory deficits, motor or autonomic dysfunction, and contribute to the development of chronic neurodegenerative diseases. The presence and proper functioning of oligodendrocyte precursor cells offer the potential for repair and recovery of injured white matter. The process of the proliferation, maturation of oligodendrocyte precursor cells and their migration to the site of injury to replace injured or lost oligodendrocytes is know as oligodendrogenesis. The process of oligodendrogenesis, as well as the interaction of oligodendrocyte precursor cells with other elements of the neurovascular unit, will be discussed in this review.
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Affiliation(s)
- Hajime Takase
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Charlestown, MA, United States; Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Neurology, Massachusetts General Hospital, Boston, MA, United States; Department of Neurosurgery, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Kazuo Washida
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Charlestown, MA, United States; Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Neurology, Massachusetts General Hospital, Boston, MA, United States; Division of Neurology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Kazuhide Hayakawa
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Charlestown, MA, United States; Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Neurology, Massachusetts General Hospital, Boston, MA, United States
| | - Ken Arai
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Charlestown, MA, United States; Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Neurology, Massachusetts General Hospital, Boston, MA, United States
| | - Xiaoying Wang
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Charlestown, MA, United States; Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Neurology, Massachusetts General Hospital, Boston, MA, United States
| | - Eng H Lo
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Charlestown, MA, United States; Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; Department of Neurology, Massachusetts General Hospital, Boston, MA, United States
| | - Josephine Lok
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Charlestown, MA, United States; Department of Pediatrics, Massachusetts General Hospital, Boston, MA, United States.
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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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Tognatta R, Miller RH. Contribution of the oligodendrocyte lineage to CNS repair and neurodegenerative pathologies. Neuropharmacology 2016; 110:539-547. [PMID: 27108096 DOI: 10.1016/j.neuropharm.2016.04.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 04/01/2016] [Accepted: 04/19/2016] [Indexed: 12/22/2022]
Abstract
The concept of the oligodendrocyte lineage as simply a source of myelinating cells in the vertebrate CNS is undergoing radical revision. Elucidation of the origins of oligodendrocytes in the CNS has led to identification of important signaling pathways, the timing and mechanism of lineage commitments and overlapping as well as redundant functionality among oligodendrocytes. The realization that a significant proportion of the oligodendrocyte lineage cells remain in a proliferative and immature state suggests they have roles other than as a reservoir of myelinating cells. While early studies were focused on understanding the development of oligodendrocytes, more recent work has begun to define the role of oligodendrocyte lineage cells in CNS functionality and the identification of new avenues for neural repair. A relatively unexplored aspect of the oligodendrocyte lineage is their contribution either directly or indirectly to the pathology of neurodegenerative diseases such as ALS and Alzheimer's disease. Here we briefly consider the potential role of oligodendrocyte lineage cells as mediators of neural repair and neurodegeneration in the vertebrate CNS. This article is part of the Special Issue entitled 'Oligodendrocytes in Health and Disease'.
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Affiliation(s)
- Reshmi Tognatta
- George Washington University, School of Medicine and Health Sciences, 2300 Eye Street NW, Ross Hall 709G, Washington, DC, 20037, USA
| | - Robert H Miller
- George Washington University, School of Medicine and Health Sciences, 2300 Eye Street NW, Ross Hall 709G, Washington, DC, 20037, USA.
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36
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Back SA. Brain Injury in the Preterm Infant: New Horizons for Pathogenesis and Prevention. Pediatr Neurol 2015; 53:185-92. [PMID: 26302698 PMCID: PMC4550810 DOI: 10.1016/j.pediatrneurol.2015.04.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 03/24/2015] [Accepted: 04/12/2015] [Indexed: 10/23/2022]
Abstract
Preterm neonates are surviving with a milder spectrum of motor and cognitive disabilities that appear to be related to widespread disturbances in cell maturation that target cerebral gray and white matter. Whereas the preterm brain was previously at high risk for destructive lesions, preterm survivors now commonly display less severe injury that is associated with aberrant regeneration and repair responses that result in reduced cerebral growth. Impaired cerebral white matter growth is related to myelination disturbances that are initiated by acute death of premyelinating oligodendrocytes, but are followed by rapid regeneration of premyelinating oligodendrocytes that fail to normally mature to myelinating cells. Although immature neurons are more resistant to cell death than mature neurons, they display widespread disturbances in maturation of their dendritic arbors and synapses, which further contributes to impaired cerebral growth. Thus, even more mild cerebral injury involves disrupted repair mechanisms in which neurons and premyelinating oligodendrocytes fail to fully mature during a critical window in development of neural circuitry. These recently recognized distinct forms of cerebral gray and white matter dysmaturation raise new diagnostic challenges and suggest new therapeutic strategies to promote brain growth and repair.
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Affiliation(s)
- Stephen A. Back
- Departments of Pediatrics and Neurology, Oregon Health & Science University, Portland, Oregon, U.S.A
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Sakry D, Trotter J. The role of the NG2 proteoglycan in OPC and CNS network function. Brain Res 2015; 1638:161-166. [PMID: 26100334 DOI: 10.1016/j.brainres.2015.06.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/27/2015] [Accepted: 06/02/2015] [Indexed: 01/13/2023]
Abstract
In the normal mammalian CNS, the NG2 proteoglycan is expressed by oligodendrocyte precursor cells (OPC) but not by any other neural cell-type. NG2 is a type-1 membrane protein, exerting multiple roles in the CNS including intracellular signaling within the OPC, with effects on migration, cytoskeleton interaction and target gene regulation. It has been recently shown that the extracellular region of NG2, in addition to an adhesive function, acts as a soluble ECM component with the capacity to alter defined neuronal network properties. This region of NG2 is thus endowed with neuromodulatory properties. In order to generate biologically active fragments yielding these properties, the sequential cleavage of the NG2 protein by α- and γ-secretases occurs. The basal level of constitutive cleavage is stimulated by neuronal network activity. This processing leads to 4 major NG2 fragments which all have been associated with distinct biological functions. Here we summarize these functions, focusing on recent discoveries and their implications for the CNS. This article is part of a Special Issue entitled SI:NG2-glia(Invited only).
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Affiliation(s)
- Dominik Sakry
- Institute of Molecular Cell Biology; Johannes Gutenberg University of Mainz, Mainz, Germany.
| | - Jacqueline Trotter
- Institute of Molecular Cell Biology; Johannes Gutenberg University of Mainz, Mainz, Germany.
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38
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Dimou L, Gallo V. NG2-glia and their functions in the central nervous system. Glia 2015; 63:1429-51. [PMID: 26010717 DOI: 10.1002/glia.22859] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 05/04/2015] [Indexed: 12/12/2022]
Abstract
In the central nervous system, NG2-glia represent a neural cell population that is distinct from neurons, astrocytes, and oligodendrocytes. While in the past the main role ascribed to these cells was that of progenitors for oligodendrocytes, in the last years it has become more obvious that they have further functions in the brain. Here, we will discuss some of the most current and highly debated issues regarding NG2-glia: Do these cells represent a heterogeneous population? Can they give rise to different progenies, and does this change under pathological conditions? How do they respond to injury or pathology? What is the role of neurotransmitter signaling between neurons and NG2-glia? We will first give an overview on the developmental origin of NG2-glia, and then discuss whether their distinct properties in different brain regions are the result of environmental influences, or due to intrinsic differences. We will then review and discuss their in vitro differentiation potential and in vivo lineage under physiological and pathological conditions, together with their electrophysiological properties in distinct brain regions and at different developmental stages. Finally, we will focus on their potential to be used as therapeutic targets in demyelinating and neurodegenerative diseases. Therefore, this review article will highlight the importance of NG2-glia not only in the healthy, but also in the diseased brain.
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Affiliation(s)
- L Dimou
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians University, Munich, 80336, Germany.,Institute for Stem Cell Research, Helmholtz Zentrum Munich, Neuherberg, 85764, Germany
| | - V Gallo
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, District of Columbia
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39
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Faissner A, Reinhard J. The extracellular matrix compartment of neural stem and glial progenitor cells. Glia 2015; 63:1330-49. [DOI: 10.1002/glia.22839] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/25/2015] [Accepted: 03/30/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology; Ruhr-University Bochum; Germany
| | - Jacqueline Reinhard
- Department of Cell Morphology and Molecular Neurobiology; Ruhr-University Bochum; Germany
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Werneburg S, Mühlenhoff M, Stangel M, Hildebrandt H. Polysialic acid on SynCAM 1 in NG2 cells and on neuropilin-2 in microglia is confined to intracellular pools that are rapidly depleted upon stimulation. Glia 2015; 63:1240-55. [DOI: 10.1002/glia.22815] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 02/20/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Sebastian Werneburg
- Hannover Medical School; Institute for Cellular Chemistry; Carl-Neuberg-Straße 1 Hannover Germany
- Center for Systems Neuroscience (ZSN); Hannover Germany
| | - Martina Mühlenhoff
- Hannover Medical School; Institute for Cellular Chemistry; Carl-Neuberg-Straße 1 Hannover Germany
| | - Martin Stangel
- Center for Systems Neuroscience (ZSN); Hannover Germany
- Clinical Neuroimmunology and Neurochemistry; Department of Neurology; Hannover Medical School; Carl-Neuberg-Straße 1 Hannover Germany
| | - Herbert Hildebrandt
- Hannover Medical School; Institute for Cellular Chemistry; Carl-Neuberg-Straße 1 Hannover Germany
- Center for Systems Neuroscience (ZSN); Hannover Germany
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Fannon J, Tarmier W, Fulton D. Neuronal activity and AMPA-type glutamate receptor activation regulates the morphological development of oligodendrocyte precursor cells. Glia 2015; 63:1021-35. [PMID: 25739948 DOI: 10.1002/glia.22799] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 01/09/2015] [Indexed: 11/11/2022]
Abstract
Myelination is initiated when oligodendrocyte precursor cells (OPC) contact target axons. Neuronal activity promotes myelination through actions that may involve OPC AMPA and NMDA glutamate receptors (AMPAR, NMDAR). Therefore, activity and AMPAR/NMDAR activation are predicted to promote the morphological development of OPC. AMPAR can regulate OPC development, but this analysis was not performed in situ and the role of action potentials was not examined. Hence, the influence of activity and AMPAR on OPC morphology and development remain untested in the CNS where axon-glial interactions are preserved. Data on NMDAR are mixed with conflicting results from in vitro and in vivo work. To gain a fuller understanding of activity-dependent OPC development in situ, we explored the role of AMPAR and NMDAR in cerebellar slice cultures that permit the study of endogenous OPC development and myelination. The structure of individual OPC was resolved from cells labeled with membrane targeted GFP. Morphological data were then validated against assays of OPC development. Blocking either activity or AMPAR impaired the morphological development of OPC and promoted proliferation and differentiation. Increasing the pool of oligodendrocytes by blocking activity or AMPAR failed to promote myelination. Instead both myelination and the expression of myelin basic protein were reduced by these treatments suggesting that full differentiation to a myelinating phenotype did not occur. Blocking NMDAR left OPC proliferation, differentiation and morphology unchanged. These data indicate an important role for AMPAR but not NMDAR in mediating the activity-dependent signals that regulate OPC morphology, development and myelination.
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Affiliation(s)
- Jessica Fannon
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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42
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Entrapment via synaptic-like connections between NG2 proteoglycan+ cells and dystrophic axons in the lesion plays a role in regeneration failure after spinal cord injury. J Neurosci 2015; 34:16369-84. [PMID: 25471575 DOI: 10.1523/jneurosci.1309-14.2014] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
NG2 is purportedly one of the most growth-inhibitory chondroitin sulfate proteoglycans (CSPGs) produced after spinal cord injury. Nonetheless, once the severed axon tips dieback from the lesion core into the penumbra they closely associate with NG2+ cells. We asked if proteoglycans play a role in this tight cell-cell interaction and whether overadhesion upon these cells might participate in regeneration failure in rodents. Studies using varying ratios of CSPGs and adhesion molecules along with chondroitinase ABC, as well as purified adult cord-derived NG2 glia, demonstrate that CSPGs are involved in entrapping neurons. Once dystrophic axons become stabilized upon NG2+ cells, they form synaptic-like connections both in vitro and in vivo. In NG2 knock-out mice, sensory axons in the dorsal columns dieback further than their control counterparts. When axons are double conditioned to enhance their growth potential, some traverse the lesion core and express reduced amounts of synaptic proteins. Our studies suggest that proteoglycan-mediated entrapment upon NG2+ cells is an additional obstacle to CNS axon regeneration.
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Funk GD, Rajani V, Alvares TS, Revill AL, Zhang Y, Chu NY, Biancardi V, Linhares-Taxini C, Katzell A, Reklow R. Neuroglia and their roles in central respiratory control; an overview. Comp Biochem Physiol A Mol Integr Physiol 2015; 186:83-95. [PMID: 25634606 DOI: 10.1016/j.cbpa.2015.01.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 01/15/2015] [Accepted: 01/16/2015] [Indexed: 01/12/2023]
Abstract
While once viewed as mere housekeepers, providing structural and metabolic support for neurons, it is now clear that neuroglia do much more. Phylogenetically, they have undergone enormous proliferation and diversification as central nervous systems grew in their complexity. In addition, they: i) are morphologically and functionally diverse; ii) play numerous, vital roles in maintaining CNS homeostasis; iii) are key players in brain development and responses to injury; and, iv) via gliotransmission, are likely participants in information processing. In this review, we discuss the diverse roles of neuroglia in maintaining homeostasis in the CNS, their evolutionary origins, the different types of neuroglia and their functional significance for respiratory control, and finally consider evidence that they contribute to the processing of chemosensory information in the respiratory network and the homeostatic control of blood gases.
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Affiliation(s)
- Gregory D Funk
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
| | - Vishaal Rajani
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Tucaauê S Alvares
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Ann L Revill
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Yong Zhang
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Nathan Y Chu
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Vivian Biancardi
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Animal Morphology and Physiology, Fac. de Ciências Agrárias e Veterinárias/UNESP, Via de Acesso Paulo Donato Castellane km 05, Jaboticabal, SP 14884-900, Brazil
| | - Camila Linhares-Taxini
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; Department of Animal Morphology and Physiology, Fac. de Ciências Agrárias e Veterinárias/UNESP, Via de Acesso Paulo Donato Castellane km 05, Jaboticabal, SP 14884-900, Brazil
| | - Alexis Katzell
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Robert Reklow
- Department of Physiology, Neuroscience and Mental Health Institute, Women and Children's Health Research Institute (WCHRI), Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Jiang P, Chen C, Liu XB, Selvaraj V, Liu W, Feldman DH, Liu Y, Pleasure DE, Li RA, Deng W. Generation and characterization of spiking and nonspiking oligodendroglial progenitor cells from embryonic stem cells. Stem Cells 2015; 31:2620-31. [PMID: 23940003 DOI: 10.1002/stem.1515] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 06/27/2013] [Accepted: 07/24/2013] [Indexed: 12/13/2022]
Abstract
Pluripotent stem cells (PSCs) have been differentiated into oligodendroglial progenitor cells (OPCs), providing promising cell replacement therapies for many central nervous system disorders. Studies from rodents have shown that brain OPCs express a variety of ion channels, and that a subset of brain OPCs express voltage-gated sodium channel (NaV ), mediating the spiking properties of OPCs. However, it is unclear whether PSC-derived OPCs exhibit electrophysiological properties similar to brain OPCs and the role of NaV in the functional maturation of OPCs is unknown. Here, using a mouse embryonic stem cell (mESC) green fluorescent protein (GFP)-Olig2 knockin reporter line, we demonstrated that unlike brain OPCs, all the GFP(+) /Olig2(+) mESC-derived OPCs (mESC-OPCs) did not express functional NaV and failed to generate spikes (hence termed "nonspiking mESC-OPCs"), while expressing the delayed rectifier and inactivating potassium currents. By ectopically expressing NaV 1.2 α subunit via viral transduction, we successfully generated mESC-OPCs with spiking properties (termed "spiking mESC-OPCs"). After transplantation into the spinal cord and brain of myelin-deficient shiverer mice, the spiking mESC-OPCs demonstrated better capability in differentiating into myelin basic protein expressing oligodendrocytes and in myelinating axons in vivo than the nonspiking mESC-OPCs. Thus, by generating spiking and nonspiking mESC-OPCs, this study reveals a novel function of NaV in OPCs in their functional maturation and myelination, and sheds new light on ways to effectively develop PSC-derived OPCs for future clinical applications.
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Affiliation(s)
- Peng Jiang
- Department of Biochemistry and Molecular Medicine, School of Medicine, Sacramento, California, USA; Institute for Pediatric Regenerative Medicine, Shriners Hospitals for Children Northern California, Sacramento, California, USA
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Oligodendrocyte precursor cells modulate the neuronal network by activity-dependent ectodomain cleavage of glial NG2. PLoS Biol 2014; 12:e1001993. [PMID: 25387269 PMCID: PMC4227637 DOI: 10.1371/journal.pbio.1001993] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 09/29/2014] [Indexed: 01/09/2023] Open
Abstract
This study shows that the activity of neurons can trigger shedding of a protein, NG2, from the surface of oligodendrocyte precursor cells; this protein in turn modulates synaptic transmission, revealing a two-way conversation between neurons and glia. The role of glia in modulating neuronal network activity is an important question. Oligodendrocyte precursor cells (OPC) characteristically express the transmembrane proteoglycan nerve-glia antigen 2 (NG2) and are unique glial cells receiving synaptic input from neurons. The development of NG2+ OPC into myelinating oligodendrocytes has been well studied, yet the retention of a large population of synapse-bearing OPC in the adult brain poses the question as to additional functional roles of OPC in the neuronal network. Here we report that activity-dependent processing of NG2 by OPC-expressed secretases functionally regulates the neuronal network. NG2 cleavage by the α-secretase ADAM10 yields an ectodomain present in the extracellular matrix and a C-terminal fragment that is subsequently further processed by the γ-secretase to release an intracellular domain. ADAM10-dependent NG2 ectodomain cleavage and release (shedding) in acute brain slices or isolated OPC is increased by distinct activity-increasing stimuli. Lack of NG2 expression in OPC (NG2-knockout mice), or pharmacological inhibition of NG2 ectodomain shedding in wild-type OPC, results in a striking reduction of N-methyl-D-aspartate (NMDA) receptor-dependent long-term potentiation (LTP) in pyramidal neurons of the somatosensory cortex and alterations in the subunit composition of their α-amino-3-hydroxy-5-methyl-4-isoxazolepr opionicacid (AMPA) receptors. In NG2-knockout mice these neurons exhibit diminished AMPA and NMDA receptor-dependent current amplitudes; strikingly AMPA receptor currents can be rescued by application of conserved LNS protein domains of the NG2 ectodomain. Furthermore, NG2-knockout mice exhibit altered behavior in tests measuring sensorimotor function. These results demonstrate for the first time a bidirectional cross-talk between OPC and the surrounding neuronal network and demonstrate a novel physiological role for OPC in regulating information processing at neuronal synapses. Although glial cells substantially outnumber neurons in the mammalian brain, much remains to be discovered regarding their functions. Among glial cells, oligodendrocyte precursors differentiate into oligodendrocytes, whose function is to enwrap nerves with myelin to ensure proper impulse conduction. However, oligodendrocyte precursors also comprise a stable population in all major regions of the adult brain, making up around 5% of the total number of neurons and glia. Synapses are classically formed between neurons. Nonetheless, oligodendrocyte precursors are unique among glial cells in that they receive direct synaptic input from different types of neurons; whether OPC also send signals to neurons is still unknown. Here we show a bidirectional communication between neurons and oligodendrocyte precursors: neuronal activity regulates the cleavage of a glial membrane protein and the release of an extracellular domain that in turn modulates synaptic transmission between neurons. Our data thus show that a particular subtype of glial cells, oligodendrocyte precursors, functionally integrate into the neuronal network and we link this bidirectional signaling to mouse behavior and disease.
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McKenzie IA, Ohayon D, Li H, de Faria JP, Emery B, Tohyama K, Richardson WD. Motor skill learning requires active central myelination. Science 2014; 346:318-22. [PMID: 25324381 PMCID: PMC6324726 DOI: 10.1126/science.1254960] [Citation(s) in RCA: 771] [Impact Index Per Article: 77.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Myelin-forming oligodendrocytes (OLs) are formed continuously in the healthy adult brain. In this work, we study the function of these late-forming cells and the myelin they produce. Learning a new motor skill (such as juggling) alters the structure of the brain's white matter, which contains many OLs, suggesting that late-born OLs might contribute to motor learning. Consistent with this idea, we show that production of newly formed OLs is briefly accelerated in mice that learn a new skill (running on a "complex wheel" with irregularly spaced rungs). By genetically manipulating the transcription factor myelin regulatory factor in OL precursors, we blocked production of new OLs during adulthood without affecting preexisting OLs or myelin. This prevented the mice from mastering the complex wheel. Thus, generation of new OLs and myelin is important for learning motor skills.
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Affiliation(s)
- Ian A McKenzie
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
| | - David Ohayon
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
| | - Huiliang Li
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
| | - Joana Paes de Faria
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
| | - Ben Emery
- Department of Anatomy and Neuroscience and the Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Koujiro Tohyama
- The Center for Electron Microscopy and Bio-Imaging Research, Iwate Medical University, 19-1 Uchimuru, Morioka, Iwate 020-8505, Japan
| | - William D Richardson
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK.
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Wennström M, Janelidze S, Bay-Richter C, Minthon L, Brundin L. Pro-inflammatory cytokines reduce the proliferation of NG2 cells and increase shedding of NG2 in vivo and in vitro. PLoS One 2014; 9:e109387. [PMID: 25285951 PMCID: PMC4186831 DOI: 10.1371/journal.pone.0109387] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/09/2014] [Indexed: 11/18/2022] Open
Abstract
Neuron glial 2 (NG2) cells become strongly activated in injured brain areas. The activation is characterized by increased proliferation as well as increased expression and shedding of the proteoglycan NG2 expressed on their cell surface. It is currently not known how these cells respond to low-grade neuroinflammation provoked by systemic inflammation. To investigate this, we analyzed NG2 cell proliferation as well as soluble NG2 (sNG2) in cerebrospinal fluid (CSF) from rats treated with an acute intraperitoneal (i.p) injection of lipopolysaccharides (LPS) or saline and sacrificed after 2 or 24 hours. The systemically induced neuroinflammation was confirmed as elevated levels of cytokines, including interleukin (IL)-6 and IL-1β, and MHCII expressing microglia were found 24 h after LPS treatment. At this time point NG2 cell proliferation was significantly decreased in both amygdala and hippocampus and sNG2 levels in CSF were increased twofold. We also exposed human NG2 cells in culture to IL-6 and IL-1β for 24 h and found, in line with our in vivo study, a direct impact of these cytokines reducing cell proliferation and increasing shedding of NG2. We conclude that LPS induced systemic inflammation significantly affects NG2 cell proliferation and shedding and that these two events at least in in part are mediated by IL-6 and IL-1β.
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Affiliation(s)
- Malin Wennström
- Lund University, Department of Clinical Sciences, Clinical Memory Research Unit, Wallenberg Laboratory, Malmö, Sweden
- * E-mail:
| | - Shorena Janelidze
- Lund University, Department of Clinical Sciences, Clinical Memory Research Unit, Wallenberg Laboratory, Malmö, Sweden
| | - Cecilie Bay-Richter
- Aarhus University, Department of Clinical Medicine, Translational Neuropsychiatry Unit, Risskov, Denmark
| | - Lennart Minthon
- Lund University, Department of Clinical Sciences, Clinical Memory Research Unit, Wallenberg Laboratory, Malmö, Sweden
| | - Lena Brundin
- Michigan State University, College of Human Medicine, Department of Psychiatry and Behavioral Medicine, Grand Rapids, Michigan, United States of America
- Van Andel Research Institute, Laboratory of Behavioral Medicine, Grand Rapids, Michigan, United States of America
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Distribution and phenotype of TrkB oligodendrocyte lineage cells in the adult rat spinal cord. Brain Res 2014; 1582:21-33. [PMID: 25072185 DOI: 10.1016/j.brainres.2014.07.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 07/18/2014] [Accepted: 07/21/2014] [Indexed: 12/12/2022]
Abstract
The distribution and phenotype of a previously undescribed population of nonneuronal cells in the intact spinal cord that expresses TrkB, the cognate receptor for brain derived neurotrophic factor (BDNF) and neurotrophin 4 (NT-4), were characterized by examining the extent of co-localization of TrkB with NG2, which identifies oligodendrocyte progenitors (OPCs) or CC1, a marker for mature oligodendrocytes (OLs). All TrkB nonneuronal cells expressed Olig2, confirming their role in the OL lineage. Similar to OPCs and OLs, TrkB cells resided in gray and white matter of the spinal cord in similar abundance. Less than 2% of TrkB cells expressed NG2, while over 80% of TrkB cells in the adult spinal cord co-expressed CC1. Most OPCs did not express detectable levels of TrkB, however a small OPC pool (~5%) showed TrkB immunoreactivity. The majority of mature OLs (~65%) expressed TrkB, but a population of mature OLs (~36%) did not express TrkB at detectable levels, and 17% of TrkB nonneuronal cells did not express NG2 or CC1. Approximately 20% of the TrkB nonneuronal population in the ventral horn resided in close proximity to motor neurons and were categorized as perineuronal. We conclude that TrkB is expressed by several pools of OL lineage cells in the adult spinal cord. These findings are important in understanding the neurotrophin regulation of OL lineage cells in the adult spinal cord.
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Boda E, Buffo A. Beyond cell replacement: unresolved roles of NG2-expressing progenitors. Front Neurosci 2014; 8:122. [PMID: 24904264 PMCID: PMC4033196 DOI: 10.3389/fnins.2014.00122] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/06/2014] [Indexed: 12/19/2022] Open
Abstract
NG2-expressing parenchymal precursors (NG2+p) serve as primary source of myelinating oligodendrocytes in both the developing and adult Central Nervous System (CNS). However, their abundance, limited differentiation potential at adult stages along with stereotypic reaction to injury independent of the extent of myelin loss suggest that NG2+p exert functions additional to myelin production. In support of this view, NG2+p express a complex battery of molecules known to exert neuromodulatory and neuroprotective functions. Further, they establish intimate physical associations with the other CNS cell types, receive functional synaptic contacts and possess ion channels apt to constantly sense the electrical activity of surrounding neurons. These latter features could endow NG2+p with the capability to affect neuronal functions with potential homeostatic outcomes. Here we summarize and discuss current evidence favoring the view that NG2+p can participate in circuit formation, modulate neuronal activity and survival in the healthy and injured CNS, and propose perspectives for studies that may complete our understanding of NG2+p roles in physiology and pathology.
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Affiliation(s)
- Enrica Boda
- Department of Neuroscience Rita Levi-Montalcini, Neuroscience Institute Cavalieri Ottolenghi, University of Turin Turin, Italy
| | - Annalisa Buffo
- Department of Neuroscience Rita Levi-Montalcini, Neuroscience Institute Cavalieri Ottolenghi, University of Turin Turin, Italy
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50
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Barateiro A, Fernandes A. Temporal oligodendrocyte lineage progression: in vitro models of proliferation, differentiation and myelination. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1917-29. [PMID: 24768715 DOI: 10.1016/j.bbamcr.2014.04.018] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 03/25/2014] [Accepted: 04/16/2014] [Indexed: 10/25/2022]
Abstract
Oligodendrocytes are neuroglial cells responsible, within the central nervous system, for myelin sheath formation that provides an electric insulation of axons and accelerate the transmission of electrical signals. In order to be able to produce myelin, oligodendrocytes progress through a series of differentiation steps from oligodendrocyte precursor cells to mature oligodendrocytes (migration, increase in morphologic complexity and expression pattern of specific markers), which are modulated by cross talk with other nerve cells. If during the developmental stage any of these mechanisms is affected by toxic or external stimuli it may result into impaired myelination leading to neurological deficits. Such being the case, several approaches have been developed to evaluate how oligodendrocyte development and myelination may be impaired. The present review aims to summarize changes that oligodendrocytes suffer from precursor cells to mature ones, and to describe and discuss the different in vitro models used to evaluate not only oligodendrocyte development (proliferation, migration, differentiation and ability to myelinate), but also their interaction with neurons and other glial cells. First we discuss the temporal oligodendrocyte lineage progression, highlighting the differences between human and rodent, usually used as tissue supply for in vitro cultures. Second we describe how to perform and characterize the different in vitro cultures, as well as the methodologies to evaluate oligodendrocyte functionality in each culture system, discussing their advantages and disadvantages. Finally, we briefly discuss the current status of in vivo models for oligodendrocyte development and myelination.
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Affiliation(s)
- Andreia Barateiro
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Av. Professor Gama Pinto, 1649-003 Lisbon, Portugal
| | - Adelaide Fernandes
- Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, University of Lisbon, Av. Professor Gama Pinto, 1649-003 Lisbon, Portugal; Department of Biochemistry and Human Biology, Faculdade de Farmácia, Universidade de Lisboa, Av. Professor Gama Pinto, 1649-003 Lisbon, Portugal.
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