1
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Carricaburu E, Benner O, Burlingham SR, Dos Santos Passos C, Hobaugh N, Karr CH, Chanda S. Gephyrin promotes autonomous assembly and synaptic localization of GABAergic postsynaptic components without presynaptic GABA release. Proc Natl Acad Sci U S A 2024; 121:e2315100121. [PMID: 38889143 PMCID: PMC11214061 DOI: 10.1073/pnas.2315100121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 05/17/2024] [Indexed: 06/20/2024] Open
Abstract
Synapses containing γ-aminobutyric acid (GABA) constitute the primary centers for inhibitory neurotransmission in our nervous system. It is unclear how these synaptic structures form and align their postsynaptic machineries with presynaptic terminals. Here, we monitored the cellular distribution of several GABAergic postsynaptic proteins in a purely glutamatergic neuronal culture derived from human stem cells, which virtually lacks any vesicular GABA release. We found that several GABAA receptor (GABAAR) subunits, postsynaptic scaffolds, and major cell-adhesion molecules can reliably coaggregate and colocalize at even GABA-deficient subsynaptic domains, but remain physically segregated from glutamatergic counterparts. Genetic deletions of both Gephyrin and a Gephyrin-associated guanosine di- or triphosphate (GDP/GTP) exchange factor Collybistin severely disrupted the coassembly of these postsynaptic compositions and their proper apposition with presynaptic inputs. Gephyrin-GABAAR clusters, developed in the absence of GABA transmission, could be subsequently activated and even potentiated by delayed supply of vesicular GABA. Thus, molecular organization of GABAergic postsynapses can initiate via a GABA-independent but Gephyrin-dependent intrinsic mechanism.
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Affiliation(s)
- Etta Carricaburu
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO80523
| | - Orion Benner
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO80523
| | - Scott R. Burlingham
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO80523
| | | | - Natalia Hobaugh
- Biological Sciences Division, University of Chicago, Chicago, IL60637
| | - Charles H. Karr
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO80523
| | - Soham Chanda
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO80523
- Molecular, Cellular and Integrated Neurosciences Program, Colorado State University, Fort Collins, CO80523
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO80523
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2
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Freitas GA, Niswender CM. GRM7 gene mutations and consequences for neurodevelopment. Pharmacol Biochem Behav 2023; 225:173546. [PMID: 37003303 PMCID: PMC10192299 DOI: 10.1016/j.pbb.2023.173546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The metabotropic glutamate receptor 7 (mGlu7), encoded by the GRM7 gene in humans, is a presynaptic, G protein-coupled glutamate receptor that is essential for modulating neurotransmission. Mutations in or reduced expression of GRM7 have been identified in different genetic neurodevelopmental disorders (NDDs), and rare biallelic missense variants have been proposed to underlie a subset of NDDs. Clinical GRM7 variants have been associated with a range of symptoms consistent with neurodevelopmental molecular features, including hypomyelination, brain atrophy and defects in axon outgrowth. Here, we review the newest findings regarding the cellular and molecular defects caused by GRM7 variants in NDD patients.
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Affiliation(s)
- Geanne A Freitas
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America
| | - Colleen M Niswender
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, United States of America.
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3
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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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4
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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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5
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Panlilio JM, Hammar KM, Aluru N, Hahn ME. Developmental exposure to domoic acid targets reticulospinal neurons and leads to aberrant myelination in the spinal cord. Sci Rep 2023; 13:2587. [PMID: 36788234 PMCID: PMC9929266 DOI: 10.1038/s41598-023-28166-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 01/13/2023] [Indexed: 02/16/2023] Open
Abstract
Harmful algal blooms (HABs) produce neurotoxins that affect human health. Developmental exposure of zebrafish embryos to the HAB toxin domoic acid (DomA) causes myelin defects, loss of reticulospinal neurons, and behavioral deficits. However, it is unclear whether DomA primarily targets myelin sheaths, leading to the loss of reticulospinal neurons, or reticulospinal neurons, causing myelin defects. Here, we show that while exposure to DomA at 2 dpf did not reduce the number of oligodendrocyte precursors prior to myelination, it led to fewer myelinating oligodendrocytes that produced shorter myelin sheaths and aberrantly wrapped neuron cell bodies. DomA-exposed larvae lacked Mauthner neurons prior to the onset of myelination, suggesting that axonal loss is not secondary to myelin defects. The loss of the axonal targets may have led oligodendrocytes to inappropriately myelinate neuronal cell bodies. Consistent with this, GANT61, a GLI1/2 inhibitor that reduces oligodendrocyte number, caused a reduction in aberrantly myelinated neuron cell bodies in DomA-exposed fish. Together, these results suggest that DomA initially alters reticulospinal neurons and the loss of axons causes aberrant myelination of nearby cell bodies. The identification of initial targets and perturbed cellular processes provides a mechanistic understanding of how DomA alters neurodevelopment, leading to structural and behavioral phenotypes.
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Affiliation(s)
- Jennifer M Panlilio
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA.
- Massachusetts Institute of Technology (MIT) - Woods Hole Oceanographic Institution (WHOI) Joint Graduate Program in Oceanography and Oceanographic Engineering, Cambridge, USA.
- Woods Hole Center for Oceans and Human Health, Woods Hole, MA, 02543, USA.
| | - Katherine M Hammar
- Central Microscopy Facility, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA
| | - Neelakanteswar Aluru
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
- Woods Hole Center for Oceans and Human Health, Woods Hole, MA, 02543, USA
| | - Mark E Hahn
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
- Woods Hole Center for Oceans and Human Health, Woods Hole, MA, 02543, USA
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6
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Akay LA, Effenberger AH, Tsai LH. Cell of all trades: oligodendrocyte precursor cells in synaptic, vascular, and immune function. Genes Dev 2021; 35:180-198. [PMID: 33526585 PMCID: PMC7849363 DOI: 10.1101/gad.344218.120] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Oligodendrocyte precursor cells (OPCs) are not merely a transitory progenitor cell type, but rather a distinct and heterogeneous population of glia with various functions in the developing and adult central nervous system. In this review, we discuss the fate and function of OPCs in the brain beyond their contribution to myelination. OPCs are electrically sensitive, form synapses with neurons, support blood-brain barrier integrity, and mediate neuroinflammation. We explore how sex and age may influence OPC activity, and we review how OPC dysfunction may play a primary role in numerous neurological and neuropsychiatric diseases. Finally, we highlight areas of future research.
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Affiliation(s)
- Leyla Anne Akay
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Audrey H Effenberger
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Li-Huei Tsai
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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7
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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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8
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Yalçın B, Monje M. Microenvironmental interactions of oligodendroglial cells. Dev Cell 2021; 56:1821-1832. [PMID: 34192527 DOI: 10.1016/j.devcel.2021.06.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/27/2021] [Accepted: 06/08/2021] [Indexed: 12/15/2022]
Abstract
Developmental myelination is a protracted process that extends well into postnatal life. Cell-intrinsic mechanisms operate in myelin-forming oligodendrocytes, as well as microenvironmental interactions that guide and modulate every aspect of myelination, from oligodendrocyte precursor cell migration to oligodendrocyte differentiation and the formation of stable myelin internodes. During development and throughout adult life, neuron-oligodendroglial interactions shape activity and experience-dependent myelin adaptations to fine-tune neural circuit dynamics and promote healthy neurological function.
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Affiliation(s)
- Belgin Yalçın
- Department of Neurology and Neurological Sciences, Stanford University, Palo Alto, CA 94304, USA
| | - Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Palo Alto, CA 94304, USA.
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9
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Coppi E, Cencetti F, Cherchi F, Venturini M, Donati C, Bruni P, Pedata F, Pugliese AM. A 2 B Adenosine Receptors and Sphingosine 1-Phosphate Signaling Cross-Talk in Oligodendrogliogenesis. Front Neurosci 2021; 15:677988. [PMID: 34135730 PMCID: PMC8202686 DOI: 10.3389/fnins.2021.677988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 04/22/2021] [Indexed: 11/13/2022] Open
Abstract
Oligodendrocyte-formed myelin sheaths allow fast synaptic transmission in the brain. Impairments in the process of myelination, or demyelinating insults, might cause chronic diseases such as multiple sclerosis (MS). Under physiological conditions, remyelination is an ongoing process throughout adult life consisting in the differentiation of oligodendrocyte progenitor cells (OPCs) into mature oligodendrocytes (OLs). During pathological events, this process fails due to unfavorable environment. Adenosine and sphingosine kinase/sphingosine 1-phosphate signaling axes (SphK/S1P) play important roles in remyelination processes. Remarkably, fingolimod (FTY720), a sphingosine analog recently approved for MS treatment, plays important roles in OPC maturation. We recently demonstrated that the selective stimulation of A2 B adenosine receptors (A2 B Rs) inhibit OPC differentiation in vitro and reduce voltage-dependent outward K+ currents (I K ) necessary to OPC maturation, whereas specific SphK1 or SphK2 inhibition exerts the opposite effect. During OPC differentiation A2 B R expression increases, this effect being prevented by SphK1/2 blockade. Furthermore, selective silencing of A2 B R in OPC cultures prompts maturation and, intriguingly, enhances the expression of S1P lyase, the enzyme responsible for irreversible S1P catabolism. Finally, the existence of an interplay between SphK1/S1P pathway and A2 B Rs in OPCs was confirmed since acute stimulation of A2 B Rs activates SphK1 by increasing its phosphorylation. Here the role of A2 B R and SphK/S1P signaling during oligodendrogenesis is reviewed in detail, with the purpose to shed new light on the interaction between A2 B Rs and S1P signaling, as eventual innovative targets for the treatment of demyelinating disorders.
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Affiliation(s)
- Elisabetta Coppi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Francesca Cencetti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Federica Cherchi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Martina Venturini
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Chiara Donati
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Paola Bruni
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Felicita Pedata
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Anna Maria Pugliese
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Section of Pharmacology and Toxicology, University of Florence, Florence, Italy
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10
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Girolamo F, de Trizio I, Errede M, Longo G, d'Amati A, Virgintino D. Neural crest cell-derived pericytes act as pro-angiogenic cells in human neocortex development and gliomas. Fluids Barriers CNS 2021; 18:14. [PMID: 33743764 PMCID: PMC7980348 DOI: 10.1186/s12987-021-00242-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 02/13/2021] [Indexed: 02/07/2023] Open
Abstract
Central nervous system diseases involving the parenchymal microvessels are frequently associated with a ‘microvasculopathy’, which includes different levels of neurovascular unit (NVU) dysfunction, including blood–brain barrier alterations. To contribute to the understanding of NVU responses to pathological noxae, we have focused on one of its cellular components, the microvascular pericytes, highlighting unique features of brain pericytes with the aid of the analyses carried out during vascularization of human developing neocortex and in human gliomas. Thanks to their position, centred within the endothelial/glial partition of the vessel basal lamina and therefore inserted between endothelial cells and the perivascular and vessel-associated components (astrocytes, oligodendrocyte precursor cells (OPCs)/NG2-glia, microglia, macrophages, nerve terminals), pericytes fulfil a central role within the microvessel NVU. Indeed, at this critical site, pericytes have a number of direct and extracellular matrix molecule- and soluble factor-mediated functions, displaying marked phenotypical and functional heterogeneity and carrying out multitasking services. This pericytes heterogeneity is primarily linked to their position in specific tissue and organ microenvironments and, most importantly, to their ontogeny. During ontogenesis, pericyte subtypes belong to two main embryonic germ layers, mesoderm and (neuro)ectoderm, and are therefore expected to be found in organs ontogenetically different, nonetheless, pericytes of different origin may converge and colonize neighbouring areas of the same organ/apparatus. Here, we provide a brief overview of the unusual roles played by forebrain pericytes in the processes of angiogenesis and barriergenesis by virtue of their origin from midbrain neural crest stem cells. A better knowledge of the ontogenetic subpopulations may support the understanding of specific interactions and mechanisms involved in pericyte function/dysfunction, including normal and pathological angiogenesis, thereby offering an alternative perspective on cell subtype-specific therapeutic approaches. ![]()
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Affiliation(s)
- Francesco Girolamo
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, Human Anatomy and Histology Unit, University of Bari School of Medicine, Bari, Italy.
| | - Ignazio de Trizio
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, Human Anatomy and Histology Unit, University of Bari School of Medicine, Bari, Italy.,Intensive Care Unit, Department of Intensive Care, Regional Hospital of Lugano, Ente Ospedaliero Cantonale, Lugano, Switzerland
| | - Mariella Errede
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, Human Anatomy and Histology Unit, University of Bari School of Medicine, Bari, Italy
| | - Giovanna Longo
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, Molecular Biology Unit, University of Bari School of Medicine, Bari, Italy
| | - Antonio d'Amati
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, Human Anatomy and Histology Unit, University of Bari School of Medicine, Bari, Italy.,Department of Emergency and Organ Transplantation, Pathology Section, University of Bari School of Medicine, Bari, Italy
| | - Daniela Virgintino
- Department of Basic Medical Sciences, Neuroscience and Sensory Organs, Human Anatomy and Histology Unit, University of Bari School of Medicine, Bari, Italy
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11
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Girolamo F, de Trizio I, Errede M, Longo G, d’Amati A, Virgintino D. Neural crest cell-derived pericytes act as pro-angiogenic cells in human neocortex development and gliomas. Fluids Barriers CNS 2021. [DOI: 10.1186/s12987-021-00242-7 union select null--] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractCentral nervous system diseases involving the parenchymal microvessels are frequently associated with a ‘microvasculopathy’, which includes different levels of neurovascular unit (NVU) dysfunction, including blood–brain barrier alterations. To contribute to the understanding of NVU responses to pathological noxae, we have focused on one of its cellular components, the microvascular pericytes, highlighting unique features of brain pericytes with the aid of the analyses carried out during vascularization of human developing neocortex and in human gliomas. Thanks to their position, centred within the endothelial/glial partition of the vessel basal lamina and therefore inserted between endothelial cells and the perivascular and vessel-associated components (astrocytes, oligodendrocyte precursor cells (OPCs)/NG2-glia, microglia, macrophages, nerve terminals), pericytes fulfil a central role within the microvessel NVU. Indeed, at this critical site, pericytes have a number of direct and extracellular matrix molecule- and soluble factor-mediated functions, displaying marked phenotypical and functional heterogeneity and carrying out multitasking services. This pericytes heterogeneity is primarily linked to their position in specific tissue and organ microenvironments and, most importantly, to their ontogeny. During ontogenesis, pericyte subtypes belong to two main embryonic germ layers, mesoderm and (neuro)ectoderm, and are therefore expected to be found in organs ontogenetically different, nonetheless, pericytes of different origin may converge and colonize neighbouring areas of the same organ/apparatus. Here, we provide a brief overview of the unusual roles played by forebrain pericytes in the processes of angiogenesis and barriergenesis by virtue of their origin from midbrain neural crest stem cells. A better knowledge of the ontogenetic subpopulations may support the understanding of specific interactions and mechanisms involved in pericyte function/dysfunction, including normal and pathological angiogenesis, thereby offering an alternative perspective on cell subtype-specific therapeutic approaches.
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12
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Kamen Y, Pivonkova H, Evans KA, Káradóttir RT. A Matter of State: Diversity in Oligodendrocyte Lineage Cells. Neuroscientist 2021; 28:144-162. [PMID: 33567971 DOI: 10.1177/1073858420987208] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Oligodendrocyte precursor cells (OPCs) give rise to oligodendrocytes which myelinate axons in the central nervous system. Although classically thought to be a homogeneous population, OPCs are reported to have different developmental origins and display regional and temporal diversity in their transcriptome, response to growth factors, and physiological properties. Similarly, evidence is accumulating that myelinating oligodendrocytes display transcriptional heterogeneity. Analyzing this reported heterogeneity suggests that OPCs, and perhaps also myelinating oligodendrocytes, may exist in different functional cell states. Here, we review the evidence indicating that OPCs and oligodendrocytes are diverse, and we discuss the implications of functional OPC states for myelination in the adult brain and for myelin repair.
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Affiliation(s)
- Yasmine Kamen
- Wellcome-Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Helena Pivonkova
- Wellcome-Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Kimberley A Evans
- Wellcome-Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Ragnhildur T Káradóttir
- Wellcome-Medical Research Council Cambridge Stem Cell Institute & Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.,Department of Physiology, BioMedical Center, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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13
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Cherchi F, Pugliese AM, Coppi E. Oligodendrocyte precursor cell maturation: role of adenosine receptors. Neural Regen Res 2021; 16:1686-1692. [PMID: 33510056 PMCID: PMC8328763 DOI: 10.4103/1673-5374.306058] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Oligodendrocyte-formed myelin sheaths allow fast synaptic transmission in the brain and their degeneration leads to demyelinating diseases such as multiple sclerosis. Remyelination requires the differentiation of oligodendrocyte progenitor cells into mature oligodendrocytes but, in chronic neurodegenerative disorders, remyelination fails due to adverse environment. Therefore, a strategy to prompt oligodendrocyte progenitor cell differentiation towards myelinating oligodendrocytes is required. The neuromodulator adenosine, and its receptors (A1, A2A, A2B and A3 receptors: A1R, A2AR, A2BR and A3R), are crucial mediators in remyelination processes. It is known that A1Rs facilitate oligodendrocyte progenitor cell maturation and migration whereas the A3Rs initiates apoptosis in oligodendrocyte progenitor cells. Our group of research contributed to the field by demonstrating that A2AR and A2BR inhibit oligodendrocyte progenitor cell maturation by reducing voltage-dependent K+ currents necessary for cell differentiation. The present review summarizes the possible role of adenosine receptor ligands as potential therapeutic targets in demyelinating pathologies such as multiple sclerosis.
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Affiliation(s)
- Federica Cherchi
- Department of Neuroscience, Psychology, Drug Research and Child Health-Neurofarba-Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Anna Maria Pugliese
- Department of Neuroscience, Psychology, Drug Research and Child Health-Neurofarba-Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
| | - Elisabetta Coppi
- Department of Neuroscience, Psychology, Drug Research and Child Health-Neurofarba-Division of Pharmacology and Toxicology, University of Florence, Florence, Italy
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14
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Chanoumidou K, Mozafari S, Baron-Van Evercooren A, Kuhlmann T. Stem cell derived oligodendrocytes to study myelin diseases. Glia 2019; 68:705-720. [PMID: 31633852 DOI: 10.1002/glia.23733] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 09/23/2019] [Accepted: 09/27/2019] [Indexed: 12/16/2022]
Abstract
Oligodendroglial pathology is central to de- and dysmyelinating, but also contributes to neurodegenerative and psychiatric diseases as well as brain injury. The understanding of oligodendroglial biology in health and disease has been significantly increased during recent years by experimental in vitro and in vivo preclinical studies as well as histological analyses of human tissue samples. However, for many of these diseases the underlying pathology is still not fully understood and treatment options are frequently lacking. This is at least partly caused by the limited access to human oligodendrocytes from patients to perform functional studies and drug screens. The induced pluripotent stem cell technology (iPSC) represents a possibility to circumvent this obstacle and paves new ways to study human disease and to develop new treatment options for so far incurable central nervous system (CNS) diseases. In this review, we summarize the differences between human and rodent oligodendrocytes, provide an overview of the different techniques to generate oligodendrocytes from human progenitor or stem cells and describe the results from studies using iPSC derived oligodendroglial lineage cells. Furthermore, we discuss future perspectives and challenges of the iPSC technology with respect to disease modeling, drug screen, and cell transplantation approaches.
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Affiliation(s)
| | - Sabah Mozafari
- Institut du Cerveau et de la Moelle Epinière-Groupe Hospitalier Pitié-Salpêtrière, INSERM, U1127; CNRS, UMR 7225; Sorbonne Université UM-75, Paris, France
| | - Anne Baron-Van Evercooren
- Institut du Cerveau et de la Moelle Epinière-Groupe Hospitalier Pitié-Salpêtrière, INSERM, U1127; CNRS, UMR 7225; Sorbonne Université UM-75, Paris, France
| | - Tanja Kuhlmann
- Institute of Neuropathology, University Hospital Münster, Münster, Germany
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15
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White Matter Stroke Induces a Unique Oligo-Astrocyte Niche That Inhibits Recovery. J Neurosci 2019; 39:9343-9359. [PMID: 31591156 DOI: 10.1523/jneurosci.0103-19.2019] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 08/21/2019] [Accepted: 09/08/2019] [Indexed: 12/15/2022] Open
Abstract
Subcortical white matter stroke is a common stroke subtype. White matter stroke stimulates adjacent oligodendrocyte progenitor cells (OPCs) to divide and migrate to the lesion, but stroke OPCs have only a limited differentiation into mature oligodendrocytes. To understand the molecular systems that are active in OPC responses in white matter stroke, OPCs were virally labeled and laser-captured in the region of partial damage adjacent to the infarct in male mice. RNAseq indicates two distinct OPC transcriptomes associated with the proliferative and limited-regeneration phases of OPCs after stroke. Molecular pathways related to nuclear receptor activation, ECM turnover, and lipid biosynthesis are activated during proliferative OPC phases after stroke; inflammatory and growth factor signaling is activated in the later stage of limited OPC differentiation. Within ECM proteins, Matrilin-2 is induced early after stroke and then rapidly downregulated. Prediction of upstream regulators of the OPC stroke transcriptome identifies several candidate molecules, including Inhibin A-a negative regulator of Matrilin-2. Inhibin A is induced in reactive astrocytes after stroke, including in humans. In functional assays, Matrilin-2 induces OPC differentiation, and Inhibin A inhibits OPC Matrilin-2 expression and inhibits OPC differentiation. In vivo, Matrilin-2 promotes motor recovery after white matter stroke, and promotes OPC differentiation and ultrastructural evidence of remyelination. These studies show that white matter stroke induces an initial proliferative and reparative response in OPCs, but this is blocked by a local cellular niche where reactive astrocytes secrete Inhibin A, downregulating Matrilin-2 and blocking myelin repair and recovery.SIGNIFICANCE STATEMENT Stroke in the cerebral white matter of the brain is common. The biology of damage and recovery in this stroke subtype are not well defined. These studies use cell-specific RNA sequencing and gain-of-function studies to show that white matter stroke induces a glial signaling niche, present in both humans and mice, between reactive astrocytes and oligodendrocyte progenitor cells. Astrocyte secretion of Inhibin A and downregulation of oligodendrocyte precursor production of Matrilin-2 limit OPC differentiation, tissue repair, and recovery in this disease.
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16
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Diverse Actions of Astrocytes in GABAergic Signaling. Int J Mol Sci 2019; 20:ijms20122964. [PMID: 31216630 PMCID: PMC6628243 DOI: 10.3390/ijms20122964] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 01/06/2023] Open
Abstract
An imbalance of excitatory and inhibitory neurotransmission leading to over excitation plays a crucial role in generating seizures, while enhancing GABAergic mechanisms are critical in terminating seizures. In recent years, it has been reported in many studies that astrocytes are deeply involved in synaptic transmission. Astrocytes form a critical component of the “tripartite” synapses by wrapping around the pre- and post-synaptic elements. From this location, astrocytes are known to greatly influence the dynamics of ions and transmitters in the synaptic cleft. Despite recent extensive research on excitatory tripartite synapses, inhibitory tripartite synapses have received less attention, even though they influence inhibitory synaptic transmission by affecting chloride and GABA concentration dynamics. In this review, we will discuss the diverse actions of astrocytic chloride and GABA homeostasis at GABAergic tripartite synapses. We will then consider the pathophysiological impacts of disturbed GABA homeostasis at the tripartite synapse.
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17
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Tsata V, Kroehne V, Reinhardt S, El-Armouche A, Brand M, Wagner M, Reimer MM. Electrophysiological Properties of Adult Zebrafish Oligodendrocyte Progenitor Cells. Front Cell Neurosci 2019; 13:102. [PMID: 31031593 PMCID: PMC6473327 DOI: 10.3389/fncel.2019.00102] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/28/2019] [Indexed: 11/13/2022] Open
Abstract
Low remyelination efficiency after spinal cord injury (SCI) is a major restraint to successful axonal and functional regeneration in mammals. In contrast, adult zebrafish can: (i) regenerate oligodendrocytes and myelin sheaths within 2 weeks post lesion; (ii) re-grow axonal projections across the lesion site and (iii) recover locomotor function within 6 weeks after spinal cord transection. However, little is known about the intrinsic properties of oligodendrocyte progenitor cells (OPCs), the remyelinating cells of the central nervous system (CNS). Here, we demonstrate that purified OPCs from the adult zebrafish spinal cord are electrically active. They functionally express voltage-gated K+ and Na+ channels, glutamate receptors and exhibit depolarizing, tetrodotoxin (TTX)-sensitive spikes, as previously seen in rodent and human OPCs. Furthermore, we show that the percentage of zebrafish OPCs exhibiting depolarizing spikes and Nav-mediated currents is lower as compared to rodent white matter OPCs, where these membrane characteristics have been shown to underlie OPC injury susceptibility. These findings imply that adult zebrafish OPCs resemble electrical properties found in mammals and represent a relevant cell type towards understanding the biology of the primary cells targeted in remyelination therapies for non-regenerative species. The in vitro platform introduced in this study could be used in the future to: (i) elucidate how membrane characteristics of zebrafish OPCs change upon injury and (ii) identify potential signaling components underlying OPC injury recognition.
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Affiliation(s)
- Vasiliki Tsata
- Center for Regenerative Therapies TU Dresden (CRTD) and Center for Molecular and Cellular Bioengineering (CMCB), Technische Universitaet, Dresden, Germany
| | - Volker Kroehne
- Center for Regenerative Therapies TU Dresden (CRTD) and Center for Molecular and Cellular Bioengineering (CMCB), Technische Universitaet, Dresden, Germany
| | - Susanne Reinhardt
- Dresden Genome Center, Center for Regenerative Therapies TU Dresden (CRTD), Center for Molecular and Cellular Bioengineering (CMCB), Technische Universitaet Dresden, Dresden, Germany
| | - Ali El-Armouche
- Department of Pharmacology and Toxicology, Technische Universitaet Dresden, Dresden, Germany
| | - Michael Brand
- Center for Regenerative Therapies TU Dresden (CRTD) and Center for Molecular and Cellular Bioengineering (CMCB), Technische Universitaet, Dresden, Germany
| | - Michael Wagner
- Department of Pharmacology and Toxicology, Technische Universitaet Dresden, Dresden, Germany.,Department of Rhythmology, Heart Center Dresden, Technische Universitaet Dresden, Dresden, Germany
| | - Michell M Reimer
- Center for Regenerative Therapies TU Dresden (CRTD) and Center for Molecular and Cellular Bioengineering (CMCB), Technische Universitaet, Dresden, Germany
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18
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Habermacher C, Angulo MC, Benamer N. Glutamate versus GABA in neuron-oligodendroglia communication. Glia 2019; 67:2092-2106. [PMID: 30957306 DOI: 10.1002/glia.23618] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/28/2019] [Accepted: 03/19/2019] [Indexed: 12/20/2022]
Abstract
In the central nervous system (CNS), myelin sheaths around axons are formed by glial cells named oligodendrocytes (OLs). In turn, OLs are generated by oligodendrocyte precursor cells (OPCs) during postnatal development and in adults, according to a process that depends on the proliferation and differentiation of these progenitors. The maturation of OL lineage cells as well as myelination by OLs are complex and highly regulated processes in the CNS. OPCs and OLs express an array of receptors for neurotransmitters, in particular for the two main CNS neurotransmitters glutamate and GABA, and are therefore endowed with the capacity to respond to neuronal activity. Initial studies in cell cultures demonstrated that both glutamate and GABA signaling mechanisms play important roles in OL lineage cell development and function. However, much remains to be learned about the communication of glutamatergic and GABAergic neurons with oligodendroglia in vivo. This review focuses on recent major advances in our understanding of the neuron-oligodendroglia communication mediated by glutamate and GABA in the CNS, and highlights the present controversies in the field. We discuss the expression, activation modes and potential roles of synaptic and extrasynaptic receptors along OL lineage progression. We review the properties of OPC synaptic connectivity with presynaptic glutamatergic and GABAergic neurons in the brain and consider the implication of glutamate and GABA signaling in activity-driven adaptive myelination.
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Affiliation(s)
- Chloé Habermacher
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,Université Paris Descartes, Paris, France
| | - María C Angulo
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,Université Paris Descartes, Paris, France
| | - Najate Benamer
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,Université Paris Descartes, Paris, France
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19
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de Faria O, Gonsalvez DG, Nicholson M, Xiao J. Activity-dependent central nervous system myelination throughout life. J Neurochem 2019; 148:447-461. [PMID: 30225984 PMCID: PMC6587454 DOI: 10.1111/jnc.14592] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 09/07/2018] [Indexed: 01/03/2023]
Abstract
Myelin, the multilayered membrane surrounding many axons in the nervous system, increases the speed by which electrical signals travel along axons and facilitates neuronal communication between distant regions of the nervous system. However, how neuronal signals influence the myelinating process in the CNS is still largely unclear. Recent studies have significantly advanced this understanding, identifying important roles for neuronal activity in controlling oligodendrocyte development and their capacity of producing myelin in both developing and mature CNS. Here, we review these recent advances, and discuss potential mechanisms underpinning activity-dependent myelination and how remyelination may be stimulated via manipulating axonal activity, raising new questions for future research.
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Affiliation(s)
- Omar de Faria
- Wellcome Trust MRC Stem Cell Institute & Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - David G. Gonsalvez
- Department of Anatomy and NeuroscienceFaculty of MedicineDentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
| | - Madeline Nicholson
- Department of Anatomy and NeuroscienceFaculty of MedicineDentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
| | - Junhua Xiao
- Department of Anatomy and NeuroscienceFaculty of MedicineDentistry and Health SciencesUniversity of MelbourneParkvilleVictoriaAustralia
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20
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Magnani D, Chandran S, Wyllie DJA, Livesey MR. In Vitro Generation and Electrophysiological Characterization of OPCs and Oligodendrocytes from Human Pluripotent Stem Cells. Methods Mol Biol 2019; 1936:65-77. [PMID: 30820893 DOI: 10.1007/978-1-4939-9072-6_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The in vitro generation of defined cellular populations from induced human pluripotent stem cells (iPSCs) provides the opportunity to work routinely with human material and, importantly, allows examination of material derived from patients with clinically and genetically diagnosed disorders. In this regard, the ability to derive oligodendrocytes in vitro represents an important resource to examine human oligodendrocyte-lineage cell biology in normal and disease contexts. Oligodendrocytes undergo characteristic physiological maturation during differentiation in vitro, and patch-clamp electrophysiology allows a detailed examination of maturation state and, potentially, pathologically related variations of ion channel expression and regulation. Here, we detail our methodology to generate oligodendrocyte precursor cells and oligodendrocytes and characterize them electrophysiologically.
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Affiliation(s)
- Dario Magnani
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK. .,Euan MacDonald Centre, The University of Edinburgh, Edinburgh, UK.
| | - Siddharthan Chandran
- Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, UK.,Euan MacDonald Centre, The University of Edinburgh, Edinburgh, UK
| | - David J A Wyllie
- Centre For Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK
| | - Matthew R Livesey
- Centre For Discovery Brain Sciences, The University of Edinburgh, Edinburgh, UK.
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21
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Chorghay Z, Káradóttir RT, Ruthazer ES. White Matter Plasticity Keeps the Brain in Tune: Axons Conduct While Glia Wrap. Front Cell Neurosci 2018; 12:428. [PMID: 30519159 PMCID: PMC6251003 DOI: 10.3389/fncel.2018.00428] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2018] [Accepted: 10/30/2018] [Indexed: 12/28/2022] Open
Abstract
Precise timing of neuronal inputs is crucial for brain circuit function and development, where it contributes critically to experience-dependent plasticity. Myelination therefore provides an important adaptation mechanism for vertebrate circuits. Despite its importance to circuit activity, the interplay between neuronal activity and myelination has yet to be fully elucidated. In recent years, significant attention has been devoted to uncovering and explaining the phenomenon of white matter (WM) plasticity. Here, we summarize some of the critical evidence for modulation of the WM by neuronal activity, ranging from human diffusion tensor imaging (DTI) studies to experiments in animal models. These experiments reveal activity-dependent changes in the differentiation and proliferation of the oligodendrocyte lineage, and in the critical properties of the myelin sheaths. We discuss the implications of such changes for synaptic function and plasticity, and present the underlying mechanisms of neuron–glia communication, with a focus on glutamatergic signaling and the axomyelinic synapse. Finally, we examine evidence that myelin plasticity may be subject to critical periods. Taken together, the present review aims to provide insights into myelination in the context of brain circuit formation and function, emphasizing the bidirectional interplay between neurons and myelinating glial cells to better inform future investigations of nervous system plasticity.
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Affiliation(s)
- Zahraa Chorghay
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Ragnhildur Thóra Káradóttir
- Department of Veterinary Medicine, Wellcome Trust - Medical Research Council Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Edward S Ruthazer
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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22
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Pfrieger FW. Learning from Barres. Glia 2018. [DOI: 10.1002/glia.23334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Frank W. Pfrieger
- Institute of Cellular and Integrative Neurosciences (INCI), CNRS UPR 3212, University of Strasbourg; Strasbourg 67084 France
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23
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Abstract
Ben Barres, who was at the heart of glial cell physiology for over 30 years, died aged 63 on December 27, 2017.[...]
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24
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Mount CW, Monje M. Wrapped to Adapt: Experience-Dependent Myelination. Neuron 2017; 95:743-756. [PMID: 28817797 PMCID: PMC5667660 DOI: 10.1016/j.neuron.2017.07.009] [Citation(s) in RCA: 122] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/05/2017] [Accepted: 07/10/2017] [Indexed: 02/03/2023]
Abstract
Activity of the nervous system has long been recognized as a critical modulator of brain structure and function. Influences of experience on the cytoarchitecture and functional connectivity of neurons have been appreciated since the classic work of Hubel and Wiesel (1963; Wiesel and Hubel, 1963a, 1963b). In recent years, a similar structural plasticity has come to light for the myelinated infrastructure of the nervous system. While an innate program of myelin development proceeds independently of nervous system activity, increasing evidence supports a role for activity-dependent, plastic changes in myelin-forming cells that influence myelin structure and neurological function. Accumulating evidence of complementary and likely temporally overlapping activity-independent and activity-dependent modes of myelination are beginning to crystallize in a model of myelin plasticity, with broad implications for neurological function in health and disease.
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Affiliation(s)
| | - Michelle Monje
- Department of Neurology, Stanford University, Stanford, CA 94305, USA.
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25
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Pérez-Samartín A, Garay E, Moctezuma JPH, Cisneros-Mejorado A, Sánchez-Gómez MV, Martel-Gallegos G, Robles-Martínez L, Canedo-Antelo M, Matute C, Arellano RO. Inwardly Rectifying K + Currents in Cultured Oligodendrocytes from Rat Optic Nerve are Insensitive to pH. Neurochem Res 2017; 42:2443-2455. [PMID: 28345117 DOI: 10.1007/s11064-017-2242-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 03/14/2017] [Accepted: 03/17/2017] [Indexed: 10/25/2022]
Abstract
Inwardly rectifying K+ (Kir) channel expression signals at an advanced stage of maturation during oligodendroglial differentiation. Knocking down their expression halts the generation of myelin and produces severe abnormalities in the central nervous system. Kir4.1 is the main subunit involved in the tetrameric structure of Kir channels in glial cells; however, the precise composition of Kir channels expressed in oligodendrocytes (OLs) remains partially unknown, as participation of other subunits has been proposed. Kir channels are sensitive to H+; thus, intracellular acidification produces Kir current inhibition. Since Kir subunits have differential sensitivity to H+, we studied the effect of intracellular acidification on Kir currents expressed in cultured OLs derived from optic nerves of 12-day-old rats. Unexpectedly, Kir currents in OLs (2-4 DIV) did not change within the pH range of 8.0-5.0, as observed when using standard whole-cell voltage-clamp recording or when preserving cytoplasmic components with the perforated patch-clamp technique. In contrast, low pH inhibited astrocyte Kir currents, which was consistent with the involvement of the Kir4.1 subunit. The H+-insensitivity expressed in OL Kir channels was not intrinsic because Kir cloning showed no difference in the sequence reported for the Kir4.1, Kir2.1, or Kir5.1 subunits. Moreover, when Kir channels were heterologously expressed in Xenopus oocytes they behaved as expected in their general properties and sensitivity to H+. It is therefore concluded that Kir channel H+-sensitivity in OLs is modulated through an extrinsic mechanism, probably by association with a modulatory component or by posttranslational modifications.
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Affiliation(s)
- Alberto Pérez-Samartín
- Achucarro Basque Center for Neuroscience, Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas, Departamento de Neurociencias, Universidad del País Vasco, 48940, Leioa, Vizcaya, Spain
| | - Edith Garay
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - Juan Pablo H Moctezuma
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - Abraham Cisneros-Mejorado
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - María Victoria Sánchez-Gómez
- Achucarro Basque Center for Neuroscience, Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas, Departamento de Neurociencias, Universidad del País Vasco, 48940, Leioa, Vizcaya, Spain
| | - Guadalupe Martel-Gallegos
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - Leticia Robles-Martínez
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico
| | - Manuel Canedo-Antelo
- Achucarro Basque Center for Neuroscience, Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas, Departamento de Neurociencias, Universidad del País Vasco, 48940, Leioa, Vizcaya, Spain
| | - Carlos Matute
- Achucarro Basque Center for Neuroscience, Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativas, Departamento de Neurociencias, Universidad del País Vasco, 48940, Leioa, Vizcaya, Spain.
| | - Rogelio O Arellano
- Laboratorio de Neurofisiología Celular, Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla, 76230, Querétaro, Mexico.
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26
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Hamilton NB, Clarke LE, Arancibia-Carcamo IL, Kougioumtzidou E, Matthey M, Káradóttir R, Whiteley L, Bergersen LH, Richardson WD, Attwell D. Endogenous GABA controls oligodendrocyte lineage cell number, myelination, and CNS internode length. Glia 2016; 65:309-321. [PMID: 27796063 PMCID: PMC5214060 DOI: 10.1002/glia.23093] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 10/07/2016] [Accepted: 10/11/2016] [Indexed: 11/30/2022]
Abstract
Adjusting the thickness and internodal length of the myelin sheath is a mechanism for tuning the conduction velocity of axons to match computational needs. Interactions between oligodendrocyte precursor cells (OPCs) and developing axons regulate the formation of myelin around axons. We now show, using organotypic cerebral cortex slices from mice expressing eGFP in Sox10‐positive oligodendrocytes, that endogenously released GABA, acting on GABAA receptors, greatly reduces the number of oligodendrocyte lineage cells. The decrease in oligodendrocyte number correlates with a reduction in the amount of myelination but also an increase in internode length, a parameter previously thought to be set by the axon diameter or to be a property intrinsic to oligodendrocytes. Importantly, while TTX block of neuronal activity had no effect on oligodendrocyte lineage cell number when applied alone, it was able to completely abolish the effect of blocking GABAA receptors, suggesting that control of myelination by endogenous GABA may require a permissive factor to be released from axons. In contrast, block of AMPA/KA receptors had no effect on oligodendrocyte lineage cell number or myelination. These results imply that, during development, GABA can act as a local environmental cue to control myelination and thus influence the conduction velocity of action potentials within the CNS. GLIA 2017;65:309–321
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Affiliation(s)
- Nicola B Hamilton
- Department of Neuroscience, Pharmacology and Physiology, University College London, London, WC1E 6BT, United Kingdom
| | - Laura E Clarke
- Department of Neuroscience, Pharmacology and Physiology, University College London, London, WC1E 6BT, United Kingdom
| | - I Lorena Arancibia-Carcamo
- Department of Neuroscience, Pharmacology and Physiology, University College London, London, WC1E 6BT, United Kingdom
| | - Eleni Kougioumtzidou
- Department of Cell and Developmental Biology, Wolfson Institute for Biomedical Research, University College London, London, WC1E 6BT, United Kingdom
| | - Moritz Matthey
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, CB2 1QR, United Kingdom
| | - Ragnhildur Káradóttir
- Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge, CB2 1QR, United Kingdom
| | - Louise Whiteley
- Department of Neuroscience, Pharmacology and Physiology, University College London, London, WC1E 6BT, United Kingdom
| | - Linda H Bergersen
- Department of Oral Biology, Brain and Muscle Energy Group, University of Oslo, Blindern, Oslo, N-0317, Norway.,Department of Anatomy, University of Oslo, Blindern, Oslo, N-0317, Norway
| | - William D Richardson
- Department of Cell and Developmental Biology, Wolfson Institute for Biomedical Research, University College London, London, WC1E 6BT, United Kingdom
| | - David Attwell
- Department of Neuroscience, Pharmacology and Physiology, University College London, London, WC1E 6BT, United Kingdom
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27
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Baraban M, Mensch S, Lyons DA. Adaptive myelination from fish to man. Brain Res 2016; 1641:149-161. [PMID: 26498877 PMCID: PMC4907128 DOI: 10.1016/j.brainres.2015.10.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 01/06/2023]
Abstract
Myelinated axons with nodes of Ranvier are an evolutionary elaboration common to essentially all jawed vertebrates. Myelin made by Schwann cells in our peripheral nervous system and oligodendrocytes in our central nervous system has been long known to facilitate rapid energy efficient nerve impulse propagation. However, it is now also clear, particularly in the central nervous system, that myelin is not a simple static insulator but that it is dynamically regulated throughout development and life. New myelin sheaths can be made by newly differentiating oligodendrocytes, and mature myelin sheaths can be stimulated to grow again in the adult. Furthermore, numerous studies in models from fish to man indicate that neuronal activity can affect distinct stages of oligodendrocyte development and the process of myelination itself. This begs questions as to how these effects of activity are mediated at a cellular and molecular level and whether activity-driven adaptive myelination is a feature common to all myelinated axons, or indeed all oligodendrocytes, or is specific to cells or circuits with particular functions. Here we review the recent literature on this topic, elaborate on the key outstanding questions in the field, and look forward to future studies that incorporate investigations in systems from fish to man that will provide further insight into this fundamental aspect of nervous system plasticity. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Affiliation(s)
- Marion Baraban
- Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Sigrid Mensch
- Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - David A Lyons
- Centre for Neuroregeneration, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK.
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28
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Livesey MR, Magnani D, Cleary EM, Vasistha NA, James OT, Selvaraj BT, Burr K, Story D, Shaw CE, Kind PC, Hardingham GE, Wyllie DJA, Chandran S. Maturation and electrophysiological properties of human pluripotent stem cell-derived oligodendrocytes. Stem Cells 2016; 34:1040-53. [PMID: 26763608 PMCID: PMC4840312 DOI: 10.1002/stem.2273] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 10/14/2015] [Accepted: 11/05/2015] [Indexed: 12/12/2022]
Abstract
Rodent‐based studies have shown that the membrane properties of oligodendrocytes play prominent roles in their physiology and shift markedly during their maturation from the oligodendrocyte precursor cell (OPC) stage. However, the conservation of these properties and maturation processes in human oligodendrocytes remains unknown, despite their dysfunction being implicated in human neurodegenerative diseases such as multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). Here, we have defined the membrane properties of human oligodendrocytes derived from pluripotent stem cells as they mature from the OPC stage, and have identified strong conservation of maturation‐specific physiological characteristics reported in rodent systems. We find that as human oligodendrocytes develop and express maturation markers, they exhibit a progressive decrease in voltage‐gated sodium and potassium channels and a loss of tetrodotoxin‐sensitive spiking activity. Concomitant with this is an increase in inwardly rectifying potassium channel activity, as well as a characteristic switch in AMPA receptor composition. All these steps mirror the developmental trajectory observed in rodent systems. Oligodendrocytes derived from mutant C9ORF72‐carryng ALS patient induced pluripotent stem cells did not exhibit impairment to maturation and maintain viability with respect to control lines despite the presence of RNA foci, suggesting that maturation defects may not be a primary feature of this mutation. Thus, we have established that the development of human oligodendroglia membrane properties closely resemble those found in rodent cells and have generated a platform to enable the impact of human neurodegenerative disease‐causing mutations on oligodendrocyte maturation to be studied. Stem Cells2016;34:1040–1053
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Affiliation(s)
- Matthew R Livesey
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Dario Magnani
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Elaine M Cleary
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Navneet A Vasistha
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Owain T James
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, Karnataka, India
| | - Bhuvaneish T Selvaraj
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Karen Burr
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - David Story
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Christopher E Shaw
- Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, De Crespigny Park, London, United Kingdom
| | - Peter C Kind
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, Karnataka, India
| | - Giles E Hardingham
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - David J A Wyllie
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom.,Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, Karnataka, India
| | - Siddharthan Chandran
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, United Kingdom.,Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, Karnataka, India
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29
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Kim JI, Ganesan S, Luo SX, Wu YW, Park E, Huang EJ, Chen L, Ding JB. Aldehyde dehydrogenase 1a1 mediates a GABA synthesis pathway in midbrain dopaminergic neurons. Science 2015; 350:102-6. [PMID: 26430123 DOI: 10.1126/science.aac4690] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Midbrain dopamine neurons are an essential component of the basal ganglia circuitry, playing key roles in the control of fine movement and reward. Recently, it has been demonstrated that γ-aminobutyric acid (GABA), the chief inhibitory neurotransmitter, is co-released by dopamine neurons. Here, we show that GABA co-release in dopamine neurons does not use the conventional GABA-synthesizing enzymes, glutamate decarboxylases GAD65 and GAD67. Our experiments reveal an evolutionarily conserved GABA synthesis pathway mediated by aldehyde dehydrogenase 1a1 (ALDH1a1). Moreover, GABA co-release is modulated by ethanol (EtOH) at concentrations seen in blood alcohol after binge drinking, and diminished ALDH1a1 leads to enhanced alcohol consumption and preference. These findings provide insights into the functional role of GABA co-release in midbrain dopamine neurons, which may be essential for reward-based behavior and addiction.
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Affiliation(s)
- Jae-Ick Kim
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Subhashree Ganesan
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Sarah X Luo
- Department of Pathology, University of California San Francisco, San Francisco, CA 94143, USA. Neuroscience Graduate Program, University of California San Francisco, San Francisco, CA 94143, USA
| | - Yu-Wei Wu
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Esther Park
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Eric J Huang
- Department of Pathology, University of California San Francisco, San Francisco, CA 94143, USA. Neuroscience Graduate Program, University of California San Francisco, San Francisco, CA 94143, USA. Pathology Service 113B, San Francisco VA Medical Center, San Francisco, CA 94121, USA
| | - Lu Chen
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Jun B Ding
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA 94304, USA. Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Palo Alto, CA 94304, USA.
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30
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Developmental expression of Kir4.1 in astrocytes and oligodendrocytes of rat somatosensory cortex and hippocampus. Int J Dev Neurosci 2015; 47:198-205. [DOI: 10.1016/j.ijdevneu.2015.09.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 09/16/2015] [Accepted: 09/16/2015] [Indexed: 12/31/2022] Open
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31
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Larson VA, Zhang Y, Bergles DE. Electrophysiological properties of NG2(+) cells: Matching physiological studies with gene expression profiles. Brain Res 2015; 1638:138-160. [PMID: 26385417 DOI: 10.1016/j.brainres.2015.09.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/31/2015] [Accepted: 09/08/2015] [Indexed: 01/11/2023]
Abstract
NG2(+) glial cells are a dynamic population of non-neuronal cells that give rise to myelinating oligodendrocytes in the central nervous system. These cells express numerous ion channels and neurotransmitter receptors, which endow them with a complex electrophysiological profile that is unique among glial cells. Despite extensive analysis of the electrophysiological properties of these cells, relatively little was known about the molecular identity of the channels and receptors that they express. The generation of new RNA-Seq datasets for NG2(+) cells has provided the means to explore how distinct genes contribute to the physiological properties of these progenitors. In this review, we systematically compare the results obtained through RNA-Seq transcriptional analysis of purified NG2(+) cells to previous physiological and molecular studies of these cells to define the complement of ion channels and neurotransmitter receptors expressed by NG2(+) cells in the mammalian brain and discuss the potential significance of the unique physiological properties of these cells. This article is part of a Special Issue entitled SI:NG2-glia(Invited only).
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Affiliation(s)
- Valerie A Larson
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ye Zhang
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Dwight E Bergles
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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32
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Abstract
Oligodendrocyte precursor cells (OPCs) originate in the ventricular zones (VZs) of the brain and spinal cord and migrate throughout the developing central nervous system (CNS) before differentiating into myelinating oligodendrocytes (OLs). It is not known whether OPCs or OLs from different parts of the VZ are functionally distinct. OPCs persist in the postnatal CNS, where they continue to divide and generate myelinating OLs at a decreasing rate throughout adult life in rodents. Adult OPCs respond to injury or disease by accelerating their cell cycle and increasing production of OLs to replace lost myelin. They also form synapses with unmyelinated axons and respond to electrical activity in those axons by generating more OLs and myelin locally. This experience-dependent "adaptive" myelination is important in some forms of plasticity and learning, for example, motor learning. We review the control of OL lineage development, including OL population dynamics and adaptive myelination in the adult CNS.
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Affiliation(s)
- Dwight E Bergles
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, WBSB 1001, Baltimore, Maryland 21205
| | - William D Richardson
- Wolfson Institute for Biomedical Research, University College London, London WC1E 6BT, United Kingdom
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33
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Glutamatergic Transmission: A Matter of Three. Neural Plast 2015; 2015:787396. [PMID: 26345375 PMCID: PMC4539489 DOI: 10.1155/2015/787396] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 03/18/2015] [Indexed: 12/11/2022] Open
Abstract
Glutamatergic transmission in the vertebrate brain requires the involvement of glia cells, in a continuous molecular dialogue. Glial glutamate receptors and transporters are key molecules that sense synaptic activity and by these means modify their physiology in the short and long term. Posttranslational modifications that regulate protein-protein interactions and modulate transmitter removal are triggered in glial cells by neuronal released glutamate. Moreover, glutamate signaling cascades in these cells are linked to transcriptional and translational control and are critically involved in the control of the so-called glutamate/glutamine shuttle and by these means in glutamatergic neurotransmission. In this contribution, we summarize our current understanding of the biochemical consequences of glutamate synaptic activity in their surrounding partners and dissect the molecular mechanisms that allow neurons to take control of glia physiology to ensure proper glutamate-mediated neuronal communication.
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34
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Coppi E, Cellai L, Maraula G, Dettori I, Melani A, Pugliese AM, Pedata F. Role of adenosine in oligodendrocyte precursor maturation. Front Cell Neurosci 2015; 9:155. [PMID: 25964740 PMCID: PMC4408841 DOI: 10.3389/fncel.2015.00155] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 04/07/2015] [Indexed: 11/21/2022] Open
Abstract
Differentiation and maturation of oligodendroglial cells are postnatal processes that involve specific morphological changes correlated with the expression of stage-specific surface antigens and functional voltage-gated ion channels. A small fraction of oligodendrocyte progenitor cells (OPCs) generated during development are maintained in an immature and slowly proliferative or quiescent state in the adult central nervous system (CNS) representing an endogenous reservoir of immature cells. Adenosine receptors are expressed by OPCs and a key role of adenosine in oligodendrocyte maturation has been recently recognized. As evaluated on OPC cultures, adenosine, by stimulating A1 receptors, promotes oligodendrocyte maturation and inhibits their proliferation; on the contrary, by stimulating A2A receptors, it inhibits oligodendrocyte maturation. A1 and A2A receptor-mediated effects are related to opposite modifications of outward delayed rectifying membrane K+ currents (IK) that are involved in the regulation of oligodendrocyte differentiation. Brain A1 and A2A receptors might represent new molecular targets for drugs useful in demyelinating pathologies, such as multiple sclerosis (MS), stroke and brain trauma.
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Affiliation(s)
- Elisabetta Coppi
- Department of Health Sciences, University of Florence Florence, Italy
| | - Lucrezia Cellai
- Department NEUROFARBA, Division of Pharmacology and Toxicology, University of Florence Florence, Italy
| | - Giovanna Maraula
- Department NEUROFARBA, Division of Pharmacology and Toxicology, University of Florence Florence, Italy
| | - Ilaria Dettori
- Department NEUROFARBA, Division of Pharmacology and Toxicology, University of Florence Florence, Italy
| | - Alessia Melani
- Department NEUROFARBA, Division of Pharmacology and Toxicology, University of Florence Florence, Italy
| | - Anna Maria Pugliese
- Department NEUROFARBA, Division of Pharmacology and Toxicology, University of Florence Florence, Italy
| | - Felicita Pedata
- Department NEUROFARBA, Division of Pharmacology and Toxicology, University of Florence Florence, Italy
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35
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Abstract
This review presents a brief overview of the γ-aminobutyric acid (GABA) system in the developing and mature central nervous system (CNS) and its potential connections to pathologies of the CNS. γ-aminobutyric acid (GABA) is a major neurotransmitter expressed from the embryonic stage and throughout life. At an early developmental stage, GABA acts in an excitatory manner and is implicated in many processes of neurogenesis, including neuronal proliferation, migration, differentiation, and preliminary circuit-building, as well as the development of critical periods. In the mature CNS, GABA acts in an inhibitory manner, a switch mediated by chloride/cation transporter expression and summarized in this review. GABA also plays a role in the development of interstitial neurons of the white matter, as well as in oligodendrocyte development. Although the underlying cellular mechanisms are not yet well understood, we present current findings for the role of GABA in neurological diseases with characteristic white matter abnormalities, including anoxic-ischemic injury, periventricular leukomalacia, and schizophrenia. Development abnormalities of the GABAergic system appear particularly relevant in the etiology of schizophrenia. This review also covers the potential role of GABA in mature brain injury, namely transient ischemia, stroke, and traumatic brain injury/post-traumatic epilepsy.
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Affiliation(s)
- Connie Wu
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53706
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA 15213, USA
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36
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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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37
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Abstract
Gamma-amino butyric acid (GABA) is the major inhibitory neurotransmitter that is known to be synthesized and released from GABAergic neurons in the brain. However, recent studies have shown that not only neurons but also astrocytes contain a considerable amount of GABA that can be released and activate GABA receptors in neighboring neurons. These exciting new findings for glial GABA raise further interesting questions about the source of GABA, its mechanism of release and regulation and the functional role of glial GABA. In this review, we highlight recent studies that identify the presence and release of GABA in glial cells, we show several proposed potential pathways for accumulation and modulation of glial intracellular and extracellular GABA content, and finally we discuss functional roles for glial GABA in the brain.
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Affiliation(s)
- Bo-Eun Yoon
- Department of Nanobiomedical Science, Dankook University Chungnam, South Korea
| | - C Justin Lee
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST) Seoul, South Korea ; Center for Neural Science and Center for Functional Connectomics, Korea Institute of Science and Technology (KIST) Seoul, South Korea
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38
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Tomassy GS, Fossati V. How big is the myelinating orchestra? Cellular diversity within the oligodendrocyte lineage: facts and hypotheses. Front Cell Neurosci 2014; 8:201. [PMID: 25120430 PMCID: PMC4112809 DOI: 10.3389/fncel.2014.00201] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 07/03/2014] [Indexed: 11/13/2022] Open
Abstract
Since monumental studies from scientists like His, Ramón y Cajal, Lorente de Nó and many others have put down roots for modern neuroscience, the scientific community has spent a considerable amount of time, and money, investigating any possible aspect of the evolution, development and function of neurons. Today, the complexity and diversity of myriads of neuronal populations, and their progenitors, is still focus of extensive studies in hundreds of laboratories around the world. However, our prevalent neuron-centric perspective has dampened the efforts in understanding glial cells, even though their active participation in the brain physiology and pathophysiology has been increasingly recognized over the years. Among all glial cells of the central nervous system (CNS), oligodendrocytes (OLs) are a particularly specialized type of cells that provide fundamental support to neuronal activity by producing the myelin sheath. Despite their functional relevance, the developmental mechanisms regulating the generation of OLs are still poorly understood. In particular, it is still not known whether these cells share the same degree of heterogeneity of their neuronal companions and whether multiple subtypes exist within the lineage. Here, we will review and discuss current knowledge about OL development and function in the brain and spinal cord. We will try to address some specific questions: do multiple OL subtypes exist in the CNS? What is the evidence for their existence and those against them? What are the functional features that define an oligodendrocyte? We will end our journey by reviewing recent advances in human pluripotent stem cell differentiation towards OLs. This exciting field is still at its earliest days, but it is quickly evolving with improved protocols to generate functional OLs from different spatial origins. As stem cells constitute now an unprecedented source of human OLs, we believe that they will become an increasingly valuable tool for deciphering the complexity of human OL identity.
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Affiliation(s)
- Giulio Srubek Tomassy
- Department of Stem Cell and Regenerative Biology, Harvard University Cambridge, MA, USA
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39
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Kegler K, Imbschweiler I, Ulrich R, Kovermann P, Fahlke C, Deschl U, Kalkuhl A, Baumgärnter W, Wewetzer K. CNS Schwann cells display oligodendrocyte precursor-like potassium channel activation and antigenic expression in vitro. J Neural Transm (Vienna) 2014; 121:569-81. [PMID: 24487976 DOI: 10.1007/s00702-014-1163-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 01/18/2014] [Indexed: 12/14/2022]
Abstract
Central nervous system (CNS) injury triggers production of myelinating Schwann cells from endogenous oligodendrocyte precursors (OLPs). These CNS Schwann cells may be attractive candidates for novel therapeutic strategies aiming to promote endogenous CNS repair. However, CNS Schwann cells have been so far mainly characterized in situ regarding morphology and marker expression, and it has remained enigmatic whether they display functional properties distinct from peripheral nervous system (PNS) Schwann cells. Potassium channels (K+) have been implicated in progenitor and glial cell proliferation after injury and may, therefore, represent a suitable pharmacological target. In the present study, we focused on the function and expression of voltage-gated K+ channels Kv(1-12) and accessory β-subunits in purified adult canine CNS and PNS Schwann cell cultures using electrophysiology and microarray analysis and characterized their antigenic phenotype. We show here that K+ channels differed significantly in both cell types. While CNS Schwann cells displayed prominent K D-mediated K+ currents, PNS Schwann cells elicited K(D-) and K(A-type) K+ currents. Inhibition of K+ currents by TEA and Ba2+ was more effective in CNS Schwann cells. These functional differences were not paralleled by differential mRNA expression of Kv(1-12) and accessory β-subunits. However, O4/A2B5 and GFAP expressions were significantly higher and lower, respectively, in CNS than in PNS Schwann cells. Taken together, this is the first evidence that CNS Schwann cells display specific properties not shared by their peripheral counterpart. Both Kv currents and increased O4/A2B5 expression were reminiscent of OLPs suggesting that CNS Schwann cells retain OLP features during maturation.
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Affiliation(s)
- Kristel Kegler
- Department of Pathology, University of Veterinary Medicine, Bünteweg 17, 30559, Hannover, Germany
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40
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Abstract
NG2 expressing oligodendrocyte precursor cells stand out from other types of glial cells by receiving classical synaptic contacts from many neurons. This unconventional form of signaling between neurons and glial cells enables NG2 cells to receive information about the activity of presynaptic neurons with high temporal and spatial precision and has been postulated to be involved in activity-dependent myelination. While this still unproven concept is generally compelling, how NG2 cells may integrate synaptic input has hardly been addressed to date. Here we review the biophysical characteristics of synaptic currents and membrane properties of NG2 cells and discuss their capabilities to perform complex temporal and spatial signal integration and how this may be important for activity-dependent myelination.
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Affiliation(s)
- Wenjing Sun
- Experimental Neurophysiology, Department of Neurosurgery, University Clinic Bonn Bonn, Germany
| | - Dirk Dietrich
- Experimental Neurophysiology, Department of Neurosurgery, University Clinic Bonn Bonn, Germany
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41
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42
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Coppi E, Cellai L, Maraula G, Pugliese AM, Pedata F. Adenosine A₂A receptors inhibit delayed rectifier potassium currents and cell differentiation in primary purified oligodendrocyte cultures. Neuropharmacology 2013; 73:301-10. [PMID: 23770463 DOI: 10.1016/j.neuropharm.2013.05.035] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 05/07/2013] [Accepted: 05/19/2013] [Indexed: 11/24/2022]
Abstract
Oligodendrocyte progenitor cells (OPCs) are a population of cycling cells which persist in the adult central nervous system (CNS) where, under opportune stimuli, they differentiate into mature myelinating oligodendrocytes. Adenosine A(2A) receptors are Gs-coupled P1 purinergic receptors which are widely distributed throughout the CNS. It has been demonstrated that OPCs express A(2A) receptors, but their functional role in these cells remains elusive. Oligodendrocytes express distinct voltage-gated ion channels depending on their maturation. Here, by electrophysiological recordings coupled with immunocytochemical labeling, we studied the effects of adenosine A(2A) receptors on membrane currents and differentiation of purified primary OPCs isolated from the rat cortex. We found that the selective A(2A) agonist, CGS21680, inhibits sustained, delayed rectifier, K(+) currents (I(K)) without modifying transient (I(A)) conductances. The effect was observed in all cells tested, independently from time in culture. CGS21680 inhibition of I(K) current was concentration-dependent (10-200 nM) and blocked in the presence of the selective A(2A) antagonist SCH58261 (100 nM). It is known that I(K) currents play an important role during OPC development since their block decreases cell proliferation and differentiation. In light of these data, our further aim was to investigate whether A(2A) receptors modulate these processes. CGS21680, applied at 100 nM in the culture medium of oligodendrocyte cultures, inhibits OPC differentiation (an effect prevented by SCH58261) without affecting cell proliferation. Data demonstrate that cultured OPCs express functional A(2A) receptors whose activation negatively modulate I(K) currents. We propose that, by this mechanism, A(2A) adenosine receptors inhibit OPC differentiation.
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Affiliation(s)
- Elisabetta Coppi
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), Division of Pharmacology and Toxicology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy
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43
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Coppi E, Maraula G, Fumagalli M, Failli P, Cellai L, Bonfanti E, Mazzoni L, Coppini R, Abbracchio MP, Pedata F, Pugliese AM. UDP-glucose enhances outward K(+) currents necessary for cell differentiation and stimulates cell migration by activating the GPR17 receptor in oligodendrocyte precursors. Glia 2013; 61:1155-71. [PMID: 23640798 DOI: 10.1002/glia.22506] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 03/13/2013] [Indexed: 01/30/2023]
Abstract
In the developing and mature central nervous system, NG2 expressing cells comprise a population of cycling oligodendrocyte progenitor cells (OPCs) that differentiate into mature, myelinating oligodendrocytes (OLGs). OPCs are also characterized by high motility and respond to injury by migrating into the lesioned area to support remyelination. K(+) currents in OPCs are developmentally regulated during differentiation. However, the mechanisms regulating these currents at different stages of oligodendrocyte lineage are poorly understood. Here we show that, in cultured primary OPCs, the purinergic G-protein coupled receptor GPR17, that has recently emerged as a key player in oligodendrogliogenesis, crucially regulates K(+) currents. Specifically, receptor stimulation by its agonist UDP-glucose enhances delayed rectifier K(+) currents without affecting transient K(+) conductances. This effect was observed in a subpopulation of OPCs and immature pre-OLGs whereas it was absent in mature OLGs, in line with GPR17 expression, that peaks at intermediate phases of oligodendrocyte differentiation and is thereafter downregulated to allow terminal maturation. The effect of UDP-glucose on K(+) currents is concentration-dependent, blocked by the GPR17 antagonists MRS2179 and cangrelor, and sensitive to the K(+) channel blocker tetraethyl-ammonium, which also inhibits oligodendrocyte maturation. We propose that stimulation of K(+) currents is responsible for GPR17-induced oligodendrocyte differentiation. Moreover, we demonstrate, for the first time, that GPR17 activation stimulates OPC migration, suggesting an important role for this receptor after brain injury. Our data indicate that modulation of GPR17 may represent a strategy to potentiate the post-traumatic response of OPCs under demyelinating conditions, such as multiple sclerosis, stroke, and brain trauma.
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Affiliation(s)
- Elisabetta Coppi
- Divi Department of Neuroscience, Psychology, Drug Research and Child Health (NeuroFarBa), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy.
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44
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Li C, Xiao L, Liu X, Yang W, Shen W, Hu C, Yang G, He C. A functional role of NMDA receptor in regulating the differentiation of oligodendrocyte precursor cells and remyelination. Glia 2013; 61:732-49. [PMID: 23440860 DOI: 10.1002/glia.22469] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 12/27/2012] [Indexed: 11/12/2022]
Abstract
Differentiation of oligodendrocyte precursor cells (OPCs) is the most important event for the myelination of central nervous system (CNS) axons during development and remyelination in demyelinating diseases, while the underlying molecular mechanisms remain largely unknown. Here we show that NMDA receptor (NMDAR) is a functional regulator of OPCs differentiation and remyelination. First, GluN1, GluN2A, and GluN2B subunits are expressed in oligodendrocyte lineage cells (OLs) in vitro and in vivo by immunostaining and Western blot analysis. Second, in a purified rat OPC culture system, NMDARs specially mediate OPCs differentiation by enhancing myelin proteins expression and the processes branching at the immature to mature oligodendrocyte transition analyzed by a serial of developmental stage-specific antigens. Moreover, pharmacological NMDAR antagonists or specific knockdown of GluN1 by RNA interference in OPCs prevents the differentiation induced by NMDA. NMDA can activate the mammalian target of rapamycin (mTOR) signal in OPCs and the pro-differentiation effect of NMDA is obstructed by the mTOR inhibitor rapamycin, suggesting NMDAR exerts its effect through mTOR-dependent mechanism. Furthermore, NMDA increases numbers of myelin segments in DRG-OPC cocultures. Finally, NMDAR specific antagonist MK801 delays remyelination in the cuprizone model examined by LFB-PAS, immunofluorescence and electron microscopy. This effect appears to result from inhibiting OPCs differentiation as more NG2(+) OPCs but less GST-π(+) mature oligodendrocytes are observed. Together, these results indicate that NMDAR plays a critical role in the regulation of OPCs differentiation in vitro and remyelination in cuprizone model which may provide potential target for the treatment of demyelination disease.
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Affiliation(s)
- Cui Li
- Institute of Neuroscience and MOE Key Laboratory of Molecular Neurobiology, Neuroscience Research Center of Changzheng Hospital, Second Military Medical University, Shanghai, 200433, China
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45
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Differentiation of oligodendrocytes from mouse induced pluripotent stem cells without serum. Transl Stroke Res 2013; 4:149-57. [PMID: 24323274 DOI: 10.1007/s12975-012-0250-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 12/24/2012] [Accepted: 12/27/2012] [Indexed: 10/27/2022]
Abstract
Cell therapy using induced pluripotent stem (iPS) cells might become a new approach for treating neonatal hypoxic-ischemic injury such as periventricular leukomalacia. To obtain appropriate donor cells for transplantation, we differentiated oligodendrocyte (OL) lineage cells from mouse iPS cells. Induction of OL lineage cell differentiation from iPS cells was carried out with a seven-step culture method. Mouse iPS cells (stage 1) were induced to form embryoid bodies for 4 days under a serum-free condition that was suitable for ectoderm induction (stage 2), following by selection of nestin-positive neural stem cells (NSCs) for 10-12 days (stage 3). NSCs were cultured in expansion medium containing fibroblast growth factor (FGF)-2 for 4 days (stage 4), induced to differentiate into glial progenitor cells by epidermal growth factor and fibroblast growth factor (FGF-2) treatment for 4-5 days (stage 5), and then into OL progenitor cells by culture in neurobasal A medium containing FGF-2 and platelet-derived growth factor for 6-8 days (stage 6). Terminal differentiation into O4-positive OLs was carried out by culture in neurobasal A containing T3 and ciliary neurotrophic factor for 7 days (stage 7). Inwardly rectifying K+ currents, which are characteristic of OLs, were detected in iPS cell-derived cells at stage 7 in whole cell clamp mode. Our data suggest that OLs can be effectively differentiated from mouse iPS cells without serum in a stepwise manner, which may be appropriate for use as donor cells in transplantation.
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Boscia F, D'Avanzo C, Pannaccione A, Secondo A, Casamassa A, Formisano L, Guida N, Scorziello A, Di Renzo G, Annunziato L. New roles of NCX in glial cells: activation of microglia in ischemia and differentiation of oligodendrocytes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 961:307-16. [PMID: 23224890 DOI: 10.1007/978-1-4614-4756-6_26] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The initiation of microglial responses to the ischemic injury involves modifications of calcium homeostasis. Changes in [Ca(2+)](i) levels have also been shown to influence the developmental processes that accompany the transition of human oligodendrocyte precursor cells (OPCs) into mature myelinating oligodendrocytes and are required for the initiation of myelination and remyelination processes.We investigated the regional and temporal changes of NCX1 protein in microglial cells of the peri-infarct and core regions after permanent middle cerebral artery occlusion (pMCAO). Interestingly, 3 and 7 days after pMCAO, NCX1 signal strongly increased in the round-shaped microglia invading the infarct core. Cultured microglial cells from the core displayed increased NCX1 expression as compared with contralateral cells and showed enhanced NCX activity in the reverse mode of operation. Similarly, NCX activity and NCX1 protein expression were significantly enhanced in BV2 microglia exposed to oxygen and glucose deprivation, whereas NCX2 and NCX3 were downregulated. Interestingly, in NCX1-silenced cells, [Ca(2+)](i) increase induced by hypoxia was completely prevented. The upregulation of NCX1 expression and activity observed in microglia after pMCAO suggests a relevant role of NCX1 in modulating microglia functions in the postischemic brain.Next, we explored whether calcium signals mediated by NCX1, NCX2, or NCX3 play a role in oligodendrocyte maturation. Functional studies, as well as mRNA and protein expression analyses, revealed that NCX1 and NCX3, but not NCX2, were divergently modulated during OPC differentiation into oligodendrocyte. In fact, while NCX1 was downregulated, NCX3 was strongly upregulated during the oligodendrocyte development. Whereas the knocking down of the NCX3 isoform in OPCs prevented the upregulation of the myelin protein markers CNPase and MBP, its overexpression induced their upregulation. Furthermore, NCX3 knockout mice exhibited not only a reduced size of spinal cord but also a marked hypomyelination, as revealed by the decrease in MBP expression and by the accompanying increase in OPCs number. Our findings indicate that calcium signaling mediated by NCX3 plays a crucial role in oligodendrocyte maturation and myelin formation.
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Affiliation(s)
- Francesca Boscia
- Department of Neuroscience, Federico II University of Naples, Naples, Italy
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Le Meur K, Mendizabal-Zubiaga J, Grandes P, Audinat E. GABA release by hippocampal astrocytes. Front Comput Neurosci 2012; 6:59. [PMID: 22912614 PMCID: PMC3421239 DOI: 10.3389/fncom.2012.00059] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 07/25/2012] [Indexed: 01/10/2023] Open
Abstract
Astrocytes can directly influence neuronal activity through the release of various transmitters acting on membrane receptors expressed by neurons. However, in contrast to glutamate and ATP for instance, the release of GABA (γ-amino-butyric acid) by astrocytes is still poorly documented. Here, we used whole-cell recordings in rat acute brain slices and electron microscopy to test whether hippocampal astrocytes release the inhibitory transmitter GABA. We observed that slow transient inhibitory currents due to the activation of GABAA receptors occur spontaneously in principal neurons of the three main hippocampal fields (CA1, CA3, and dentate gyrus). These currents share characteristics with the slow NMDA receptor-mediated currents previously shown to result from astrocytic glutamate release: they occur in the absence of synaptic transmission and have variable kinetics and amplitudes as well as low frequencies. Osmotic pressure reduction, known to enhance transmitter release from astrocytes, similarly increased the frequency of non-synaptic GABA and glutamate currents. Simultaneous occurrence of slow inhibitory and excitatory currents was extremely rare. Yet, electron microscopy examination of immunostained hippocampal sections shows that about 80% of hippocampal astrocytes [positive for glial fibrillary acidic protein (GFAP)] were immunostained for GABA. Our results provide quantitative characteristics of the astrocyte-to-neuron GABAergic signaling. They also suggest that all principal neurons of the hippocampal network are under a dual, excitatory and inhibitory, influence of astrocytes. The relevance of the astrocytic release of GABA, and glutamate, on the physiopathology of the hippocampus remains to be established.
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Abstract
Glial cells play a key role in nervous system function, providing neurotrophic factor support to neurons as well as taking part in two-way neuron-glia signaling (e.g., neurotransmitter release). White matter-derived glia are important in certain neurodegenerative diseases involving axonal loss, for example in multiple sclerosis. Here we describe procedures for the preparation and culture of mixed nerve cells from postnatal rat optic nerve, followed by protocols which can serve for the purification of individual populations of glia from this tissue, namely O2A progenitors and oligodendrocytes, and astrocytes and astrocyte precursors.
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Affiliation(s)
- Stephen D Skaper
- Department of Pharmacology and Anesthesiology, University of Padova, Padova, Italy.
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Yoon BE, Woo J, Lee CJ. Astrocytes as GABA-ergic and GABA-ceptive cells. Neurochem Res 2012; 37:2474-9. [PMID: 22700085 DOI: 10.1007/s11064-012-0808-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 05/21/2012] [Accepted: 05/23/2012] [Indexed: 10/28/2022]
Abstract
GABA (gamma-aminobutyric acid) is considered to be the major inhibitory neurotransmitter that is synthesized in and released from GABA-ergic neurons in the brain. However, recent studies have shown that not only neurons but astrocytes contain a considerable amount of GABA, which can be released and activate the receptors responsive to GABA. In addition, astrocytes are themselves responsive to GABA by expressing GABA receptors. These exciting new findings raise more questions about the origin of GABA, whether it is synthesized or taken up, and about the role of astrocytic GABA and GABA receptors. In this review, we propose several potential pathways for astrocytes to accumulate GABA and discuss the evidence for functional expression of GABA receptors in astrocytes.
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Affiliation(s)
- Bo-Eun Yoon
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 136-791, Korea
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Cesetti T, Ciccolini F, Li Y. GABA Not Only a Neurotransmitter: Osmotic Regulation by GABA(A)R Signaling. Front Cell Neurosci 2012; 6:3. [PMID: 22319472 PMCID: PMC3268181 DOI: 10.3389/fncel.2012.00003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 01/10/2012] [Indexed: 12/05/2022] Open
Abstract
Mature macroglia and almost all neural progenitor types express γ-aminobutyric (GABA) A receptors (GABAARs), whose activation by ambient or synaptic GABA, leads to influx or efflux of chloride (Cl−) depending on its electro-chemical gradient (ECl). Since the flux of Cl− is indissolubly associated to that of osmotically obliged water, GABAARs regulate water movements by modulating ion gradients. In addition, since water movements also occur through specialized water channels and transporters, GABAAR signaling could affect the movement of water by regulating the function of the channels and transporters involved, thereby affecting not only the direction of the water fluxes but also their dynamics. We will here review recent observations indicating that in neural cells GABAAR-mediated osmotic regulation affects the cellular volume thereby activating multiple intracellular signaling mechanisms important for cell proliferation, maturation, and survival. In addition, we will discuss evidence that the osmotic regulation exerted by GABA may contribute to brain water homeostasis in physiological and in pathological conditions causing brain edema, in which the GABAergic transmission is often altered.
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Affiliation(s)
- Tiziana Cesetti
- Department of Physiology and Pathophysiology, Interdisciplinary Center for Neurosciences, University of Heidelberg Heidelberg, Germany
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