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Song Q, Wu X, Yang J, Li S, Duan J. Glial connexins in glaucoma. Front Neurosci 2025; 19:1560344. [PMID: 40270762 PMCID: PMC12014763 DOI: 10.3389/fnins.2025.1560344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2025] [Accepted: 03/24/2025] [Indexed: 04/25/2025] Open
Abstract
Glial cells play a crucial role in maintaining central nervous system (CNS) homeostasis and facilitating the repair of neural tissue following injury. The regulation of neuroglia may serve as a safe and effective strategy for modulating neuroinflammatory responses and restoring glial homeostasis and defense functions. Given that the glial network is composed of connexin (CX) proteins, its neuroprotective role is extensive. Therefore, connexins should be considered as functional "bridges" within this network. This review examines evidence for the active involvement of glial networks in neuroinflammation under both physiological and pathological conditions and summarizes the role of CXs in glaucoma. Finally, potential therapeutic strategies for glaucoma are explored.
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Affiliation(s)
- Qiuyi Song
- Chengdu University of TCM, Chengdu, China
- Eye College of Chengdu University of TCM, Chengdu, China
| | - Xi Wu
- Chengdu University of TCM, Chengdu, China
- Eye College of Chengdu University of TCM, Chengdu, China
| | - Jiawei Yang
- Chengdu University of TCM, Chengdu, China
- Eye College of Chengdu University of TCM, Chengdu, China
- Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection with TCM Laboratory, Chengdu, China
| | - Siqi Li
- Chengdu University of TCM, Chengdu, China
| | - Junguo Duan
- Chengdu University of TCM, Chengdu, China
- Eye College of Chengdu University of TCM, Chengdu, China
- Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection with TCM Laboratory, Chengdu, China
- Ineye Hospital of Chengdu University of TCM, Chengdu, China
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2
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Das S, Shaw AK, Das Sarma S, Koval M, Das Sarma J, Maulik M. Neurotropic Murine β-Coronavirus Infection Causes Differential Expression of Connexin 47 in Oligodendrocyte Subpopulations Associated with Demyelination. Mol Neurobiol 2025; 62:3428-3445. [PMID: 39292341 PMCID: PMC11790745 DOI: 10.1007/s12035-024-04482-0] [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: 03/04/2024] [Accepted: 09/05/2024] [Indexed: 09/19/2024]
Abstract
Gap junctions (GJs) play a crucial role in the survival of oligodendrocytes and myelination of the central nervous system (CNS). In this study, we investigated the spatiotemporal changes in the expression of oligodendroglial GJ protein connexin 47 (Cx47), its primary astroglial coupling partner, Cx43, and their association with demyelination following intracerebral infection with mouse hepatitis virus (MHV). Neurotropic strains of MHV, a β-coronavirus, induce an acute encephalomyelitis followed by a chronic demyelinating disease that shares similarities with the human disease multiple sclerosis (MS). Our results reveal that Cx47 GJs are persistently lost in mature oligodendrocytes, not only in demyelinating lesions but also in surrounding normal appearing white and gray matter areas, following an initial loss of astroglial Cx43 GJs during acute infection. At later stages after viral clearance, astroglial Cx43 GJs re-emerge but mature oligodendrocytes fail to fully re-establish GJs with astrocytes due to lack of Cx47 GJ expression. In contrast, at this later demyelinating stage, the increased oligodendrocyte precursor cells appear to exhibit Cx47 GJs. Our findings further highlight varying degrees of demyelination in distinct spinal cord regions, with the thoracic cord showing the most pronounced demyelination. The regional difference in demyelination correlates well with dynamic changes in the proportion of different oligodendrocyte lineage cells exhibiting differential Cx47 GJ expression, suggesting an important mechanism of progressive demyelination even after viral clearance.
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Affiliation(s)
- Soubhik Das
- Biotechnology Research and Innovation Council - National Institute of Biomedical Genomics (BRIC-NIBMG), Kalyani, 741251, West Bengal, India
| | - Archana Kumari Shaw
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, West Bengal, India
| | - Subhajit Das Sarma
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, West Bengal, India
| | - Michael Koval
- Departments of Medicine and Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Jayasri Das Sarma
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, West Bengal, India
| | - Mahua Maulik
- Biotechnology Research and Innovation Council - National Institute of Biomedical Genomics (BRIC-NIBMG), Kalyani, 741251, West Bengal, India.
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3
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Yuan Y, Liu H, Dai Z, He C, Qin S, Su Z. From Physiology to Pathology of Astrocytes: Highlighting Their Potential as Therapeutic Targets for CNS Injury. Neurosci Bull 2025; 41:131-154. [PMID: 39080102 PMCID: PMC11748647 DOI: 10.1007/s12264-024-01258-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/15/2024] [Indexed: 01/19/2025] Open
Abstract
In the mammalian central nervous system (CNS), astrocytes are the ubiquitous glial cells that have complex morphological and molecular characteristics. These fascinating cells play essential neurosupportive and homeostatic roles in the healthy CNS and undergo morphological, molecular, and functional changes to adopt so-called 'reactive' states in response to CNS injury or disease. In recent years, interest in astrocyte research has increased dramatically and some new biological features and roles of astrocytes in physiological and pathological conditions have been discovered thanks to technological advances. Here, we will review and discuss the well-established and emerging astroglial biology and functions, with emphasis on their potential as therapeutic targets for CNS injury, including traumatic and ischemic injury. This review article will highlight the importance of astrocytes in the neuropathological process and repair of CNS injury.
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Affiliation(s)
- Yimin Yuan
- Institute of Neuroscience, Key Laboratory of Molecular Neurobiology of Ministry of Education and the Collaborative Innovation Center for Brain Science, Naval Medical University, Shanghai, 200433, China
- Department of Pain Medicine, School of Anesthesiology, Naval Medical University, Shanghai, 200433, China
| | - Hong Liu
- Institute of Neuroscience, Key Laboratory of Molecular Neurobiology of Ministry of Education and the Collaborative Innovation Center for Brain Science, Naval Medical University, Shanghai, 200433, China
| | - Ziwei Dai
- Institute of Neuroscience, Key Laboratory of Molecular Neurobiology of Ministry of Education and the Collaborative Innovation Center for Brain Science, Naval Medical University, Shanghai, 200433, China
| | - Cheng He
- Institute of Neuroscience, Key Laboratory of Molecular Neurobiology of Ministry of Education and the Collaborative Innovation Center for Brain Science, Naval Medical University, Shanghai, 200433, China
| | - Shangyao Qin
- Institute of Neuroscience, Key Laboratory of Molecular Neurobiology of Ministry of Education and the Collaborative Innovation Center for Brain Science, Naval Medical University, Shanghai, 200433, China.
| | - Zhida Su
- Institute of Neuroscience, Key Laboratory of Molecular Neurobiology of Ministry of Education and the Collaborative Innovation Center for Brain Science, Naval Medical University, Shanghai, 200433, China.
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4
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Verkhratsky A, Semyanov A. Physiology of neuroglia of the central nervous system. HANDBOOK OF CLINICAL NEUROLOGY 2025; 209:69-91. [PMID: 40122632 DOI: 10.1016/b978-0-443-19104-6.00005-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/25/2025]
Abstract
Neuroglia of the central nervous system (CNS) are a diverse and highly heterogeneous population of cells of ectodermal, neuroepithelial origin (macroglia, that includes astroglia and oligodendroglia) and mesodermal, myeloid origin (microglia). Neuroglia are primary homeostatic cells of the CNS, responsible for the support, defense, and protection of the nervous tissue. The extended class of astroglia (which includes numerous parenchymal astrocytes, such as protoplasmic, fibrous, velate, marginal, etc., radial astrocytes such as Bergmann glia, Muller glia, etc., and ependymoglia lining the walls of brain ventricles and central canal of the spinal cord) is primarily responsible for overall homeostasis of the nervous tissue. Astroglial cells control homeostasis of ions, neurotransmitters, hormones, metabolites, and are responsible for neuroprotection and defense of the CNS. Oligodendroglia provide for myelination of axons, hence supporting and sustaining CNS connectome. Microglia are tissue macrophages adapted to the CNS environment which contribute to the host of physiologic functions including regulation of synaptic connectivity through synaptic pruning, regulation of neurogenesis, and even modifying neuronal excitability. Neuroglial cells express numerous receptors, transporters, and channels that allow neuroglia to perceive and follow neuronal activity. Activation of these receptors triggers intracellular ionic signals that govern various homeostatic cascades underlying glial supportive and defensive capabilities. Ionic signaling therefore represents the substrate of glial excitability.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom; Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Bizkaia, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Alexey Semyanov
- Department of Physiology, Jiaxing University College of Medicine, Jiaxing, Zhejiang, China
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Sutley-Koury SN, Anderson A, Taitano-Johnson C, Ajayi M, Kulinich AO, Contreras K, Regalado J, Tiwari-Woodruff SK, Ethell IM. Astrocytic Ephrin-B1 Regulates Oligodendrocyte Development and Myelination. ASN Neuro 2024; 16:2401753. [PMID: 39437409 PMCID: PMC11792131 DOI: 10.1080/17590914.2024.2401753] [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] [Indexed: 10/25/2024] Open
Abstract
Astrocytes have been implicated in oligodendrocyte development and myelination, however, the mechanisms by which astrocytes regulate oligodendrocytes remain unclear. Our findings suggest a new mechanism that regulates astrocyte-mediated oligodendrocyte development through ephrin-B1 signaling in astrocytes. Using a mouse model, we examined the role of astrocytic ephrin-B1 signaling in oligodendrocyte development by deleting ephrin-B1 specifically in astrocytes during the postnatal days (P)14-P28 period and used mRNA analysis, immunohistochemistry, and mouse behaviors to study its effects on oligodendrocytes and myelination. We found that deletion of astrocytic ephrin-B1 downregulated many genes associated with oligodendrocyte development, myelination, and lipid metabolism in the hippocampus and the corpus callosum. Additionally, we observed a reduced number of oligodendrocytes and impaired myelination in the corpus callosum of astrocyte-specific ephrin-B1 KO mice. Finally, our data show reduced motor strength in these mice exhibiting clasping phenotype and impaired performance in the rotarod test most likely due to impaired myelination. Our studies provide new evidence that astrocytic ephrin-B1 positively regulates oligodendrocyte development and myelination, potentially through astrocyte-oligodendrocyte interactions.
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Affiliation(s)
- Samantha N. Sutley-Koury
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, California, USA
| | - Alyssa Anderson
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, California, USA
| | - Christopher Taitano-Johnson
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, California, USA
- Neuroscience Graduate Program, University of California Riverside, Riverside, California, USA
| | - Moyinoluwa Ajayi
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, California, USA
| | - Anna O. Kulinich
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, California, USA
| | - Kimberly Contreras
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, California, USA
| | - Jasmin Regalado
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, California, USA
| | - Seema K. Tiwari-Woodruff
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, California, USA
- Neuroscience Graduate Program, University of California Riverside, Riverside, California, USA
| | - Iryna M. Ethell
- Division of Biomedical Sciences and Biomedical Sciences Graduate Program, School of Medicine, University of California Riverside, Riverside, California, USA
- Neuroscience Graduate Program, University of California Riverside, Riverside, California, USA
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6
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Ghézali G, Ribot J, Curry N, Pillet LE, Boutet-Porretta F, Mozheiko D, Calvo CF, Ezan P, Perfettini I, Lecoin L, Janel S, Zapata J, Escartin C, Etienne-Manneville S, Kaminski CF, Rouach N. Connexin 30 locally controls actin cytoskeleton and mechanical remodeling in motile astrocytes. Glia 2024; 72:1915-1929. [PMID: 38982826 DOI: 10.1002/glia.24590] [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: 06/07/2022] [Revised: 06/04/2024] [Accepted: 06/25/2024] [Indexed: 07/11/2024]
Abstract
During brain maturation, astrocytes establish complex morphologies unveiling intense structural plasticity. Connexin 30 (Cx30), a gap-junction channel-forming protein expressed postnatally, dynamically regulates during development astrocyte morphological properties by controlling ramification and extension of fine processes. However, the underlying mechanisms remain unexplored. Here, we found in vitro that Cx30 interacts with the actin cytoskeleton in astrocytes and inhibits its structural reorganization and dynamics during cell migration. This translates into an alteration of local physical surface properties, as assessed by correlative imaging using stimulated emission depletion (STED) super resolution imaging and atomic force microscopy (AFM). Specifically, Cx30 impaired astrocyte cell surface topology and cortical stiffness in motile astrocytes. As Cx30 alters actin organization, dynamics, and membrane physical properties, we assessed whether it controls astrocyte migration. We found that Cx30 reduced persistence and directionality of migrating astrocytes. Altogether, these data reveal Cx30 as a brake for astrocyte structural and mechanical plasticity.
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Affiliation(s)
- Grégory Ghézali
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
- Doctoral School N° 158, Sorbonne Université, Paris, France
| | - Jérôme Ribot
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
| | - Nathan Curry
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Laure-Elise Pillet
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
- Doctoral School N°562, Université Paris Cité, Paris, France
| | - Flora Boutet-Porretta
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
- Doctoral School N° 158, Sorbonne Université, Paris, France
| | - Daria Mozheiko
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
- Doctoral School N° 158, Sorbonne Université, Paris, France
| | - Charles-Félix Calvo
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
| | - Pascal Ezan
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
| | - Isabelle Perfettini
- Institut Pasteur, Université de Paris, CNRS, Cell Polarity, Migration and Cancer Unit, Paris, France
| | - Laure Lecoin
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
| | - Sébastien Janel
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, CIIL - Center for Infection and Immunity of Lille, Lille, France
| | - Jonathan Zapata
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
| | - Carole Escartin
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France
| | | | - Clemens F Kaminski
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, Paris, France
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK
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Yu Y, Liao X, Xie X, Li Q, Chen X, Liu R. The role of neuroglial cells communication in ischemic stroke. Brain Res Bull 2024; 209:110910. [PMID: 38423190 DOI: 10.1016/j.brainresbull.2024.110910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/02/2024]
Abstract
Ischemic stroke is one of the leading causes of death and disability globally, but its treatment options are limited due to therapeutic window and reperfusion injury constraints. Microglia, astrocytes, and oligodendrocytes are the major components of the neurovascular unit, and there is substantial evidence suggesting their contributions to maintaining homeostasis in the central nervous system. Neuroglial cells participate in neuronal physiological functions and the repair of damaged neurons through various communication methods, including gap junctions, chemical signaling, and extracellular vesicles, in conjunction with other components of the neurovascular unit. Ischemia-induced microglia and astrocytes polarize into "M1/M2" and "A1/A2" phenotypes and exert neurotoxic or neuroprotective effects by releasing soluble factors, secreting extracellular vesicles, and forming syncytia networks in the acute (<72 h), subacute (>72 h), and chronic phases (>6 weeks). Apoptosis of oligodendrocytes due to ischemic hypoxia leads to white matter injury, causing long-term cognitive dysfunction, and promoting oligodendrogenesis is a crucial direction for achieving functional recovery in ischemic stroke. In this article, we summarize the cellular interactions following cerebral ischemia, analyze the roles of neuroglial cells through gap junctions, chemical signaling, and extracellular vesicles in different stages of ischemic stroke, and further explore strategies for intervening in ischemic stroke.
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Affiliation(s)
- Yunling Yu
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou 341000, China; School of Basic Medicine, Gannan Medical University, Ganzhou 341000, China
| | - Xinglan Liao
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou 341000, China; School of Basic Medicine, Gannan Medical University, Ganzhou 341000, China
| | - Xinyu Xie
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou 341000, China; School of Basic Medicine, Gannan Medical University, Ganzhou 341000, China
| | - Qihua Li
- School of Basic Medicine, Gannan Medical University, Ganzhou 341000, China
| | - Xuehong Chen
- School of Basic Medicine, Gannan Medical University, Ganzhou 341000, China
| | - Ruizhen Liu
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases of Ministry of Education, Gannan Medical University, Ganzhou 341000, China; School of Basic Medicine, Gannan Medical University, Ganzhou 341000, China.
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Abrams CK. Mechanisms of Diseases Associated with Mutation in GJC2/Connexin 47. Biomolecules 2023; 13:biom13040712. [PMID: 37189458 DOI: 10.3390/biom13040712] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 05/17/2023] Open
Abstract
Connexins are members of a family of integral membrane proteins that provide a pathway for both electrical and metabolic coupling between cells. Astroglia express connexin 30 (Cx30)-GJB6 and Cx43-GJA1, while oligodendroglia express Cx29/Cx31.3-GJC3, Cx32-GJB1, and Cx47-GJC2. Connexins organize into hexameric hemichannels (homomeric if all subunits are identical or heteromeric if one or more differs). Hemichannels from one cell then form cell-cell channels with a hemichannel from an apposed cell. (These are termed homotypic if the hemichannels are identical and heterotypic if the hemichannels differ). Oligodendrocytes couple to each other through Cx32/Cx32 or Cx47/Cx47 homotypic channels and they couple to astrocytes via Cx32/Cx30 or Cx47/Cx43 heterotypic channels. Astrocytes couple via Cx30/Cx30 and Cx43/Cx43 homotypic channels. Though Cx32 and Cx47 may be expressed in the same cells, all available data suggest that Cx32 and Cx47 cannot interact heteromerically. Animal models wherein one or in some cases two different CNS glial connexins have been deleted have helped to clarify the role of these molecules in CNS function. Mutations in a number of different CNS glial connexin genes cause human disease. Mutations in GJC2 lead to three distinct phenotypes, Pelizaeus Merzbacher like disease, hereditary spastic paraparesis (SPG44) and subclinical leukodystrophy.
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Affiliation(s)
- Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine, Chicago, IL 60612, USA
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Zlomuzica A, Plank L, Kodzaga I, Dere E. A fatal alliance: Glial connexins, myelin pathology and mental disorders. J Psychiatr Res 2023; 159:97-115. [PMID: 36701970 DOI: 10.1016/j.jpsychires.2023.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/02/2023] [Accepted: 01/09/2023] [Indexed: 01/12/2023]
Abstract
Mature oligodendrocytes are myelin forming glial cells which are responsible for myelination of neuronal axons in the white matter of the central nervous system. Myelin pathology is a major feature of severe neurological disorders. Oligodendrocyte-specific gene mutations and/or white matter alterations have also been addressed in a variety of mental disorders. Breakdown of myelin integrity and demyelination is associated with severe symptoms, including impairments in motor coordination, breathing, dysarthria, perception (vision and hearing), and cognition. Furthermore, there is evidence indicating that myelin sheath defects and white matter pathology contributes to the affective and cognitive symptoms of patients with mental disorders. Oligodendrocytes express the connexins GJC2; mCx47 [human (GJC2) and mouse (mCx47) connexin gene nomenclature according to Söhl and Willecke (2003)], GJB1; mCx32, and GJD1; mCx29 in both white and gray matter. Preclinical findings indicate that alterations in connexin expression in oligodendrocytes and astrocytes can induce myelin defects. GJC2; mCx47 is expressed at early embryonic stages in oligodendrocyte precursors cells which precedes central nervous system myelination. In adult humans and animals GJC2, respectively mCx47 expression is essential for oligodendrocyte function and ensures adequate myelination as well as myelin maintenance in the central nervous system. In the past decade, evidence has accumulated suggesting that mental disorders can be accompanied by changes in connexin expression, myelin sheath defects and corresponding white matter alterations. This dual pathology could compromise inter-neuronal information transfer, processing and communication and eventually contribute to behavioral, sensory-motor, affective and cognitive symptoms in patients with mental disorders. The induction of myelin repair and remyelination in the central nervous system of patients with mental disorders could help to restore normal neuronal information propagation and ameliorate behavioral and cognitive symptoms in individuals with mental disorders.
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Affiliation(s)
- Armin Zlomuzica
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787, Bochum, Germany.
| | - Laurin Plank
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787, Bochum, Germany
| | - Iris Kodzaga
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787, Bochum, Germany
| | - Ekrem Dere
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787, Bochum, Germany; Sorbonne Université, UFR des Sciences de la Vie, 9 quai Saint Bernard, F-75005, Paris, France.
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10
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Pechlivanidou M, Kousiappa I, Angeli S, Sargiannidou I, Koupparis AM, Papacostas SS, Kleopa KA. Glial Gap Junction Pathology in the Spinal Cord of the 5xFAD Mouse Model of Early-Onset Alzheimer's Disease. Int J Mol Sci 2022; 23:15597. [PMID: 36555237 PMCID: PMC9779687 DOI: 10.3390/ijms232415597] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/22/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
Gap junctions (GJs) are specialized transmembrane channels assembled by two hemi-channels of six connexin (Cx) proteins that facilitate neuroglial crosstalk in the central nervous system (CNS). Previous studies confirmed the crucial role of glial GJs in neurodegenerative disorders with dementia or motor dysfunction including Alzheimer's disease (AD). The aim of this study was to examine the alterations in astrocyte and related oligodendrocyte GJs in association with Aβ plaques in the spinal cord of the 5xFAD mouse model of AD. Our analysis revealed abundant Aβ plaque deposition, activated microglia, and astrogliosis in 12-month-old (12M) 5xFAD mice, with significant impairment of motor performance starting from 3-months (3M) of age. Additionally, 12M 5xFAD mice displayed increased immunoreactivity of astroglial Cx43 and Cx30 surrounding Aβ plaques and higher protein levels, indicating upregulated astrocyte-to-astrocyte GJ connectivity. In addition, they demonstrated increased numbers of mature CC1-positive and precursor oligodendrocytes (OPCs) with higher immunoreactivity of Cx47-positive GJs in individual cells. Moreover, total Cx47 protein levels were significantly elevated in 12M 5xFAD, reflecting increased oligodendrocyte-to-oligodendrocyte Cx47-Cx47 GJ connectivity. In contrast, we observed a marked reduction in Cx32 protein levels in 12M 5xFAD spinal cords compared with controls, while qRT-PCR analysis revealed a significant upregulation in Cx32 mRNA levels. Finally, myelin deficits were found focally in the areas occupied by Aβ plaques, whereas axons themselves remained preserved. Overall, our data provide novel insights into the altered glial GJ expression in the spinal cord of the 5xFAD model of AD and the implicated role of GJ pathology in neurodegeneration. Further investigation to understand the functional consequences of these extensive alterations in oligodendrocyte-astrocyte (O/A) GJ connectivity is warranted.
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Affiliation(s)
- Maria Pechlivanidou
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Ioanna Kousiappa
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Stella Angeli
- Medical School, University of Nicosia, Nicosia 2414, Cyprus
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Andreas M. Koupparis
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Epilepsy Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Dementia and Cognitive Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Savvas S. Papacostas
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Medical School, University of Nicosia, Nicosia 2414, Cyprus
- Epilepsy Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Dementia and Cognitive Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Center for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Center for Multiple Sclerosis and Related Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
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11
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Gargareta VI, Reuschenbach J, Siems SB, Sun T, Piepkorn L, Mangana C, Späte E, Goebbels S, Huitinga I, Möbius W, Nave KA, Jahn O, Werner HB. Conservation and divergence of myelin proteome and oligodendrocyte transcriptome profiles between humans and mice. eLife 2022; 11:77019. [PMID: 35543322 PMCID: PMC9094742 DOI: 10.7554/elife.77019] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/22/2022] [Indexed: 12/12/2022] Open
Abstract
Human myelin disorders are commonly studied in mouse models. Since both clades evolutionarily diverged approximately 85 million years ago, it is critical to know to what extent the myelin protein composition has remained similar. Here, we use quantitative proteomics to analyze myelin purified from human white matter and find that the relative abundance of the structural myelin proteins PLP, MBP, CNP, and SEPTIN8 correlates well with that in C57Bl/6N mice. Conversely, multiple other proteins were identified exclusively or predominantly in human or mouse myelin. This is exemplified by peripheral myelin protein 2 (PMP2), which was specific to human central nervous system myelin, while tetraspanin-2 (TSPAN2) and connexin-29 (CX29/GJC3) were confined to mouse myelin. Assessing published scRNA-seq-datasets, human and mouse oligodendrocytes display well-correlating transcriptome profiles but divergent expression of distinct genes, including Pmp2, Tspan2, and Gjc3. A searchable web interface is accessible via www.mpinat.mpg.de/myelin. Species-dependent diversity of oligodendroglial mRNA expression and myelin protein composition can be informative when translating from mouse models to humans.
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Affiliation(s)
- Vasiliki-Ilya Gargareta
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Josefine Reuschenbach
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Sophie B Siems
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Ting Sun
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Lars Piepkorn
- Neuroproteomics Group, Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Translational Neuroproteomics Group, Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Georg-August-University, Göttingen, Germany
| | - Carolina Mangana
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Erik Späte
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Sandra Goebbels
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Inge Huitinga
- University of Amsterdam, Swammerdam Institute for Life Sciences, Brain Plasticity Group, Amsterdam, Netherlands.,Neuroimmunology Group, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy Unit, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Olaf Jahn
- Neuroproteomics Group, Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Translational Neuroproteomics Group, Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Georg-August-University, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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12
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Activation of the unfolded protein response by Connexin47 mutations associated with Pelizaeus-Merzbacher-like disease. Mol Cell Neurosci 2022; 120:103716. [PMID: 35276347 DOI: 10.1016/j.mcn.2022.103716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 11/23/2022] Open
Abstract
Pelizaeus-Merzbacher-like disease type 1 (PMLD1) is a hypomyelinating disorder arising in patients with mutations in GJC2, encoding Connexin47 (Cx47). PMLD1 causes nystagmus, cerebellar ataxia, spasticity and changes in CNS white matter detected by MRI. At least one mutation (p.I33M) yields a much milder phenotype, spastic paraplegia type 44 (SPG44). Cx47 contributes to gap junction communication channels between oligodendrocytes (OLs), the myelinating cells in the central nervous system (CNS), and between OLs and astrocytes. Prior studies in cell lines have shown that PMLD1 mutants such as p.P87S display defective protein trafficking, intracellular retention in the ER and loss-of-function. Here we show that when expressed in primary OLs, three PMLD1 associated mutants (p.P87S, p.Y269D and p.M283T) show ER retention of Cx47 and evidence of activation of the cellular stress (unfolded protein response, UPR) and apoptotic pathways. On the other hand, the milder SPG44 associated mutation p.I33M shows a wild-type-like subcellular distribution and no activation of the UPR or apoptotic pathways. These studies provide new insight into a potential element of toxic gain of function underlying the mechanism of PMLD1 that should help guide future therapeutic approaches.
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13
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Twible C, Abdo R, Zhang Q. Astrocyte Role in Temporal Lobe Epilepsy and Development of Mossy Fiber Sprouting. Front Cell Neurosci 2021; 15:725693. [PMID: 34658792 PMCID: PMC8514632 DOI: 10.3389/fncel.2021.725693] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/02/2021] [Indexed: 11/13/2022] Open
Abstract
Epilepsy affects approximately 50 million people worldwide, with 60% of adult epilepsies presenting an onset of focal origin. The most common focal epilepsy is temporal lobe epilepsy (TLE). The role of astrocytes in the presentation and development of TLE has been increasingly studied and discussed within the literature. The most common histopathological diagnosis of TLE is hippocampal sclerosis. Hippocampal sclerosis is characterized by neuronal cell loss within the Cornu ammonis and reactive astrogliosis. In some cases, mossy fiber sprouting may be observed. Mossy fiber sprouting has been controversial in its contribution to epileptogenesis in TLE patients, and the mechanisms surrounding the phenomenon have yet to be elucidated. Several studies have reported that mossy fiber sprouting has an almost certain co-existence with reactive astrogliosis within the hippocampus under epileptic conditions. Astrocytes are known to play an important role in the survival and axonal outgrowth of central and peripheral nervous system neurons, pointing to a potential role of astrocytes in TLE and associated cellular alterations. Herein, we review the recent developments surrounding the role of astrocytes in the pathogenic process of TLE and mossy fiber sprouting, with a focus on proposed signaling pathways and cellular mechanisms, histological observations, and clinical correlations in human patients.
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Affiliation(s)
- Carolyn Twible
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada
| | - Rober Abdo
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada.,Department of Anatomy and Cell Biology, Western University, London, ON, Canada
| | - Qi Zhang
- Department of Pathology and Lab Medicine, Western University, London, ON, Canada.,Department of Pathology and Lab Medicine, London Health Sciences Centre, University Hospital, London, ON, Canada
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14
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Abrams CK, Flores-Obando RE, Dungan GD, Cherepanova E, Freidin MM. Investigating oligodendrocyte connexins: Heteromeric interactions between Cx32 and mutant or wild-type forms of Cx47 do not contribute to or modulate gap junction function. Glia 2021; 69:1882-1896. [PMID: 33835612 DOI: 10.1002/glia.23999] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 11/11/2022]
Abstract
Oligodendrocytes express two gap junction forming connexins, connexin 32 (Cx32) and Cx47; therefore, formation of heteromeric channels containing both Cx47 and Cx32 monomers might occur. Mutations in Cx47 cause both Pelizaeus-Merzbacher-like disease Type 1 (PMLD1) and hereditary spastic paraparesis Type 44 (SPG44) and heteromer formation between these mutants and Cx32 may contribute to the pathogenesis of these disorders. Here, we utilized electrophysiological and antibody-based techniques to examine this possibility. When cells expressing both Cx32 and Cx47 were paired with cells expressing either Cx32 or Cx47, properties were indistinguishable from those produced by cells expressing homotypic Cx32 or Cx47 channels. Similarly, pairing cells expressing both Cx32 and Cx47 with cells expressing Cx30 or Cx43 produced channels indistinguishable from heterotypic Cx32/Cx30 or Cx47/Cx43 channels, respectively. The same assessments were performed on cells expressing Cx32 and four mutant forms of Cx47 (p.I33M associated with SPG44 or p.P87S, p.Y269D or p.M283T associated with PMLD1). None of these mutants showed a functional effect on Cx32. Immunostained cells co-expressing Cx32WT (wild type) and Cx47WT showed a Pearson correlation coefficient close to zero, suggesting that any overlap was due to chance. p.Y269D showed a statistically significant negative correlation with Cx32, suggesting that Cx32 and this mutant overlap less than expected by chance. Co-immunoprecipitation of Cx32 with Cx47WT and mutants show only very low levels of co-immunoprecipitated protein. Overall, our data suggest that interactions between PMLD1 or SPG44 mutants and Cx32 gap junctions do not contribute to the pathogenesis of these disorders.
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Affiliation(s)
- Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA
- Department of Neurology, SUNY Downstate Medical Center, Brooklyn, New York, USA
| | | | - Gabriel D Dungan
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA
| | - Elina Cherepanova
- Department of Neurology, SUNY Downstate Medical Center, Brooklyn, New York, USA
| | - Mona M Freidin
- Department of Neurology and Rehabilitation, University of Illinois at Chicago College of Medicine, Chicago, Illinois, USA
- Department of Neurology, SUNY Downstate Medical Center, Brooklyn, New York, USA
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15
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Ojeda-Pérez B, Campos-Sandoval JA, García-Bonilla M, Cárdenas-García C, Páez-González P, Jiménez AJ. Identification of key molecular biomarkers involved in reactive and neurodegenerative processes present in inherited congenital hydrocephalus. Fluids Barriers CNS 2021; 18:30. [PMID: 34215285 PMCID: PMC8254311 DOI: 10.1186/s12987-021-00263-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 06/19/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Periventricular extracellular oedema, myelin damage, inflammation, and glial reactions are common neuropathological events that occur in the brain in congenital hydrocephalus. The periventricular white matter is the most affected region. The present study aimed to identify altered molecular and cellular biomarkers in the neocortex that can function as potential therapeutic targets to both treat and evaluate recovery from these neurodegenerative conditions. The hyh mouse model of hereditary hydrocephalus was used for this purpose. METHODS The hyh mouse model of hereditary hydrocephalus (hydrocephalus with hop gait) and control littermates without hydrocephalus were used in the present work. In tissue sections, the ionic content was investigated using energy dispersive X-ray spectroscopy scanning electron microscopy (EDS-SEM). For the lipid analysis, matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) was performed in frozen sections. The expression of proteins in the cerebral white matter was analysed by mass spectrometry. The oligodendrocyte progenitor cells (OPCs) were studied with immunofluorescence in cerebral sections and whole-mount preparations of the ventricle walls. RESULTS High sodium and chloride concentrations were found indicating oedema conditions in both the periventricular white matter and extending towards the grey matter. Lipid analysis revealed lower levels of two phosphatidylinositol molecular species in the grey matter, indicating that neural functions were altered in the hydrocephalic mice. In addition, the expression of proteins in the cerebral white matter revealed evident deregulation of the processes of oligodendrocyte differentiation and myelination. Because of the changes in oligodendrocyte differentiation in the white matter, OPCs were also studied. In hydrocephalic mice, OPCs were found to be reactive, overexpressing the NG2 antigen but not giving rise to an increase in mature oligodendrocytes. The higher levels of the NG2 antigen, diacylglycerophosphoserine and possibly transthyretin in the cerebrum of hydrocephalic hyh mice could indicate cell reactions that may have been triggered by inflammation, neurocytotoxic conditions, and ischaemia. CONCLUSION Our results identify possible biomarkers of hydrocephalus in the cerebral grey and white matter. In the white matter, OPCs could be reacting to acquire a neuroprotective role or as a delay in the oligodendrocyte maturation.
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Affiliation(s)
- Betsaida Ojeda-Pérez
- Department of Cell Biology, Genetics, and Physiology, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Malaga, Spain
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain
| | - José A Campos-Sandoval
- Servicios Centrales de Apoyo a la Investigación (SCAI), Universidad de Malaga, Malaga, Spain
| | - María García-Bonilla
- Department of Cell Biology, Genetics, and Physiology, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Malaga, Spain
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain
| | | | - Patricia Páez-González
- Department of Cell Biology, Genetics, and Physiology, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Malaga, Spain.
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain.
| | - Antonio J Jiménez
- Department of Cell Biology, Genetics, and Physiology, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071, Malaga, Spain.
- Instituto de Investigación Biomédica de Málaga (IBIMA), Malaga, Spain.
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16
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Huang X, Su Y, Wang N, Li H, Li Z, Yin G, Chen H, Niu J, Yi C. Astroglial Connexins in Neurodegenerative Diseases. Front Mol Neurosci 2021; 14:657514. [PMID: 34122008 PMCID: PMC8192976 DOI: 10.3389/fnmol.2021.657514] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 05/05/2021] [Indexed: 12/16/2022] Open
Abstract
Astrocytes play a crucial role in the maintenance of the normal functions of the Central Nervous System (CNS). During the pathogenesis of neurodegenerative diseases, astrocytes undergo morphological and functional remodeling, a process called reactive astrogliosis, in response to the insults to the CNS. One of the key aspects of the reactive astrocytes is the change in the expression and function of connexins. Connexins are channel proteins that highly expressed in astrocytes, forming gap junction channels and hemichannels, allowing diffusional trafficking of small molecules. Alterations of astrocytic connexin expression and function found in neurodegenerative diseases have been shown to affect the disease progression by changing neuronal function and survival. In this review, we will summarize the role of astroglial connexins in neurodegenerative diseases including Alzheimer’s disease, Huntington’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Also, we will discuss why targeting connexins can be a plausible therapeutic strategy to manage these neurodegenerative diseases.
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Affiliation(s)
- Xiaomin Huang
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Yixun Su
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Nan Wang
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Hui Li
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Zhigang Li
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Guowei Yin
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Hui Chen
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, Australia
| | - Jianqin Niu
- Chongqing Key Laboratory of Neurobiology, Department of Histology and Embryology, Army Medical University (Third Military Medical University), Chongqing, China
| | - Chenju Yi
- Research Centre, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
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17
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Charvériat M, Mouthon F, Rein W, Verkhratsky A. Connexins as therapeutic targets in neurological and neuropsychiatric disorders. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166098. [PMID: 33545299 DOI: 10.1016/j.bbadis.2021.166098] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/06/2021] [Accepted: 01/19/2021] [Indexed: 12/16/2022]
Abstract
Astrocytes represent the reticular part of the central nervous system; gap junctions formed by connexins Cx43, Cx30- and Cx26 provide for homocellular astrocyte-astrocyte coupling, whereas connexins Cx30, Cx32, Cx43, and Cx47 connect astrocytes and oligodendrocytes. Astroglial networks are anatomically and functionally segregated being homologous to neuronal ensembles. Connexons, gap junctions and hemichannels (unpaired connexons) are affected in various neuropathologies from neuropsychiatric to neurodegenerative diseases. Manipulation of astrocytic connexins modulates the size and outreach of astroglial syncytia thus affecting astroglial homeostatic support. Modulation of astrocytic connexin significantly modifies pharmacological profile of many CNS drugs, which represents an innovative therapeutic approach for CNS disorders; this approach is now actively tested in pre-clinical and clinical studies. Wide combination of connexin modulators with CNS drugs open new promising perspectives for fundamental studies and therapeutic strategies.
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Affiliation(s)
| | | | | | - A Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9PT, UK; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
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18
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Mozafari S, Deboux C, Laterza C, Ehrlich M, Kuhlmann T, Martino G, Baron-Van Evercooren A. Beneficial contribution of induced pluripotent stem cell-progeny to Connexin 47 dynamics during demyelination-remyelination. Glia 2020; 69:1094-1109. [PMID: 33301181 PMCID: PMC7984339 DOI: 10.1002/glia.23950] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/26/2020] [Accepted: 11/30/2020] [Indexed: 12/17/2022]
Abstract
Oligodendrocytes are extensively coupled to astrocytes, a phenomenon ensuring glial homeostasis and maintenance of central nervous system myelin. Molecular disruption of this communication occurs in demyelinating diseases such as multiple sclerosis. Less is known about the vulnerability and reconstruction of the panglial network during adult demyelination‐remyelination. Here, we took advantage of lysolcithin‐induced demyelination to investigate the expression dynamics of the oligodendrocyte specific connexin 47 (Cx47) and to some extent that of astrocyte Cx43, and whether this dynamic could be modulated by grafted induced pluripotent stem cell (iPSC)‐neural progeny. Our data show that disruption of Cx43‐Cx47 mediated hetero‐cellular gap‐junction intercellular communication following demyelination is larger in size than demyelination. Loss of Cx47 expression is timely rescued during remyelination and accelerated by the grafted neural precursors. Moreover, mouse and human iPSC‐derived oligodendrocytes express Cx47, which co‐labels with astrocyte Cx43, indicating their integration into the panglial network. These data suggest that in rodents, full lesion repair following transplantation occurs by panglial reconstruction in addition to remyelination. Targeting panglial elements by cell therapy or pharmacological compounds may help accelerating or stabilizing re/myelination in myelin disorders.
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Affiliation(s)
- Sabah Mozafari
- INSERM, U1127, Paris, France.,CNRS, UMR 7225, Paris, France.,Sorbonne Université UPMC Paris 06, UM-75, Paris, France.,ICM-GH Pitié-Salpêtrière, Paris, France
| | - Cyrille Deboux
- INSERM, U1127, Paris, France.,CNRS, UMR 7225, Paris, France.,Sorbonne Université UPMC Paris 06, UM-75, Paris, France.,ICM-GH Pitié-Salpêtrière, Paris, France
| | - Cecilia Laterza
- Institute of Experimental Neurology-DIBIT 2, Division of Neuroscience, IRCCS San Raffaele Hospital and Vita San Raffaele University, Milan, Italy.,Industrial Engineering Department, University of Padova, Padova, Italy
| | - Marc Ehrlich
- Department of Cell and Developmental Biology, Max Planck Institute for Molecular Biomedicine, Münster, Germany.,Institute of Neuropathology, University Hospital Münster, Münster, Germany
| | - Tanja Kuhlmann
- Institute of Neuropathology, University Hospital Münster, Münster, Germany
| | - Gianvito Martino
- Institute of Experimental Neurology-DIBIT 2, Division of Neuroscience, IRCCS San Raffaele Hospital and Vita San Raffaele University, Milan, Italy
| | - Anne Baron-Van Evercooren
- INSERM, U1127, Paris, France.,CNRS, UMR 7225, Paris, France.,Sorbonne Université UPMC Paris 06, UM-75, Paris, France.,ICM-GH Pitié-Salpêtrière, Paris, France
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19
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Abou-Mrad Z, Alomari SO, Bsat S, Moussalem CK, Alok K, El Houshiemy MN, Alomari AO, Minassian GB, Omeis IA. Role of connexins in spinal cord injury: An update. Clin Neurol Neurosurg 2020; 197:106102. [DOI: 10.1016/j.clineuro.2020.106102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/16/2020] [Accepted: 07/18/2020] [Indexed: 01/25/2023]
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20
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Liang Z, Wang X, Hao Y, Qiu L, Lou Y, Zhang Y, Ma D, Feng J. The Multifaceted Role of Astrocyte Connexin 43 in Ischemic Stroke Through Forming Hemichannels and Gap Junctions. Front Neurol 2020; 11:703. [PMID: 32849190 PMCID: PMC7411525 DOI: 10.3389/fneur.2020.00703] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/09/2020] [Indexed: 12/13/2022] Open
Abstract
Ischemic stroke is a multi-factorial cerebrovascular disease with high worldwide morbidity and mortality. In the past few years, multiple studies have revealed the underlying mechanism of ischemia/reperfusion injury, including calcium overload, amino acid toxicity, oxidative stress, and inflammation. Connexin 43 (Cx43), the predominant connexin protein in astrocytes, has been recently proven to display non-substitutable roles in the pathology of ischemic stroke development and progression through forming gap junctions and hemichannels. Under normal conditions, astrocytic Cx43 could be found in hemichannels or in the coupling with other hemichannels on astrocytes, neurons, or oligodendrocytes to form the neuro-glial syncytium, which is involved in metabolites exchange between communicated cells, thus maintaining the homeostasis of the CNS environment. In ischemic stroke, the phosphorylation of Cx43 might cause the degradation of gap junctions and the opening of hemichannels, contributing to the release of inflammatory mediators. However, the remaining gap junctions could facilitate the exchange of protective and harmful metabolites between healthy and injured cells, protecting the injured cells to some extent or damaging the healthy cells depending on the balance of the exchange of protective and harmful metabolites. In this study, we review the changes in astrocytic Cx43 expression and distribution as well as the influence of these changes on the function of astrocytes and other cells in the CNS, providing new insight into the pathology of ischemic stroke injury; we also discuss the potential of astrocytic Cx43 as a target for the treatment of ischemic stroke.
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Affiliation(s)
- Zhen Liang
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Xu Wang
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Yulei Hao
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Lin Qiu
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Yingyue Lou
- Department of Plastic and Reconstructive Surgery, The First Hospital of Jilin University, Changchun, China
| | - Yaoting Zhang
- Department of Cardiology, The First Hospital of Jilin University, Changchun, China
| | - Di Ma
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
| | - Jiachun Feng
- Department of Neurology and Neuroscience Center, The First Hospital of Jilin University, Changchun, China
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21
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Papaneophytou C, Georgiou E, Kleopa KA. The role of oligodendrocyte gap junctions in neuroinflammation. Channels (Austin) 2020; 13:247-263. [PMID: 31232168 PMCID: PMC6602578 DOI: 10.1080/19336950.2019.1631107] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Gap junctions (GJs) provide channels for direct cell-to-cell connectivity serving the homeostasis in several organs of vertebrates including the central (CNS) and peripheral (PNS) nervous systems. GJs are composed of connexins (Cx), which show a highly distinct cellular and subcellular expression pattern. Oligodendrocytes, the myelinating cells of the CNS, are characterized by extensive GJ connectivity with each other as well as with astrocytes. The main oligodendrocyte connexins forming these GJ channels are Cx47 and Cx32. The importance of these channels has been highlighted by the discovery of human diseases caused by mutations in oligodendrocyte connexins, manifesting with leukodystrophy or transient encephalopathy. Experimental models have provided further evidence that oligodendrocyte GJs are essential for CNS myelination and homeostasis, while a strong inflammatory component has been recognized in the absence of oligodendrocyte connexins. Further studies revealed that connexins are also disrupted in multiple sclerosis (MS) brain, and in experimental models of induced inflammatory demyelination. Moreover, induced demyelination was more severe and associated with higher degree of CNS inflammation in models with oligodendrocyte GJ deficiency, suggesting that disrupted connexin expression in oligodendrocytes is not only a consequence but can also drive a pro-inflammatory environment in acquired demyelinating disorders such as MS. In this review, we summarize the current insights from human disorders as well as from genetic and acquired models of demyelination related to oligodendrocyte connexins, with the remaining challenges and perspectives.
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Affiliation(s)
- Christos Papaneophytou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,b Department of Life and Health Sciences, School of Sciences and Engineering , University of Nicosia , Nicosia , Cyprus
| | - Elena Georgiou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus
| | - Kleopas A Kleopa
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,c Neurology Clinics , the Cyprus Institute of Neurology and Genetics, and the Cyprus School of Molecular Medicine , Nicosia , Cyprus
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22
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Giaume C, Naus CC, Sáez JC, Leybaert L. Glial Connexins and Pannexins in the Healthy and Diseased Brain. Physiol Rev 2020; 101:93-145. [PMID: 32326824 DOI: 10.1152/physrev.00043.2018] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Over the past several decades a large amount of data have established that glial cells, the main cell population in the brain, dynamically interact with neurons and thus impact their activity and survival. One typical feature of glia is their marked expression of several connexins, the membrane proteins forming intercellular gap junction channels and hemichannels. Pannexins, which have a tetraspan membrane topology as connexins, are also detected in glial cells. Here, we review the evidence that connexin and pannexin channels are actively involved in dynamic and metabolic neuroglial interactions in physiological as well as in pathological situations. These features of neuroglial interactions open the way to identify novel non-neuronal aspects that allow for a better understanding of behavior and information processing performed by neurons. This will also complement the "neurocentric" view by facilitating the development of glia-targeted therapeutic strategies in brain disease.
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Affiliation(s)
- Christian Giaume
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Christian C Naus
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Juan C Sáez
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB)/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050, Paris, France; University Pierre et Marie Curie, Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, Paris, France; Department of Cellular & Physiological Sciences, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile; Instituo de Neurociencias, Centro Interdisciplinario de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile; Physiology Group, Department of Basic and Applied Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
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23
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Verkhratsky A, Parpura V, Vardjan N, Zorec R. Physiology of Astroglia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:45-91. [PMID: 31583584 DOI: 10.1007/978-981-13-9913-8_3] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Astrocytes are principal cells responsible for maintaining the brain homeostasis. Additionally, these glial cells are also involved in homocellular (astrocyte-astrocyte) and heterocellular (astrocyte-other cell types) signalling and metabolism. These astroglial functions require an expression of the assortment of molecules, be that transporters or pumps, to maintain ion concentration gradients across the plasmalemma and the membrane of the endoplasmic reticulum. Astrocytes sense and balance their neurochemical environment via variety of transmitter receptors and transporters. As they are electrically non-excitable, astrocytes display intracellular calcium and sodium fluctuations, which are not only used for operative signalling but can also affect metabolism. In this chapter we discuss the molecules that achieve ionic gradients and underlie astrocyte signalling.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK. .,Faculty of Health and Medical Sciences, Center for Basic and Translational Neuroscience, University of Copenhagen, 2200, Copenhagen, Denmark. .,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
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24
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Stadelmann C, Timmler S, Barrantes-Freer A, Simons M. Myelin in the Central Nervous System: Structure, Function, and Pathology. Physiol Rev 2019; 99:1381-1431. [PMID: 31066630 DOI: 10.1152/physrev.00031.2018] [Citation(s) in RCA: 394] [Impact Index Per Article: 65.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocytes generate multiple layers of myelin membrane around axons of the central nervous system to enable fast and efficient nerve conduction. Until recently, saltatory nerve conduction was considered the only purpose of myelin, but it is now clear that myelin has more functions. In fact, myelinating oligodendrocytes are embedded in a vast network of interconnected glial and neuronal cells, and increasing evidence supports an active role of oligodendrocytes within this assembly, for example, by providing metabolic support to neurons, by regulating ion and water homeostasis, and by adapting to activity-dependent neuronal signals. The molecular complexity governing these interactions requires an in-depth molecular understanding of how oligodendrocytes and axons interact and how they generate, maintain, and remodel their myelin sheaths. This review deals with the biology of myelin, the expanded relationship of myelin with its underlying axons and the neighboring cells, and its disturbances in various diseases such as multiple sclerosis, acute disseminated encephalomyelitis, and neuromyelitis optica spectrum disorders. Furthermore, we will highlight how specific interactions between astrocytes, oligodendrocytes, and microglia contribute to demyelination in hereditary white matter pathologies.
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Affiliation(s)
- Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Sebastian Timmler
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Alonso Barrantes-Freer
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Mikael Simons
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
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25
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Diseases of connexins expressed in myelinating glia. Neurosci Lett 2019; 695:91-99. [DOI: 10.1016/j.neulet.2017.05.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/15/2017] [Accepted: 05/19/2017] [Indexed: 11/23/2022]
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26
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Vejar S, Oyarzún JE, Retamal MA, Ortiz FC, Orellana JA. Connexin and Pannexin-Based Channels in Oligodendrocytes: Implications in Brain Health and Disease. Front Cell Neurosci 2019; 13:3. [PMID: 30760982 PMCID: PMC6361860 DOI: 10.3389/fncel.2019.00003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/07/2019] [Indexed: 11/13/2022] Open
Abstract
Oligodendrocytes are the myelin forming cells in the central nervous system (CNS). In addition to this main physiological function, these cells play key roles by providing energy substrates to neurons as well as information required to sustain proper synaptic transmission and plasticity at the CNS. The latter requires a fine coordinated intercellular communication with neurons and other glial cell types, including astrocytes. In mammals, tissue synchronization is mainly mediated by connexins and pannexins, two protein families that underpin the communication among neighboring cells through the formation of different plasma membrane channels. At one end, gap junction channels (GJCs; which are exclusively formed by connexins in vertebrates) connect the cytoplasm of contacting cells allowing electrical and metabolic coupling. At the other end, hemichannels and pannexons (which are formed by connexins and pannexins, respectively) communicate the intra- and extracellular compartments, serving as diffusion pathways of ions and small molecules. Here, we briefly review the current knowledge about the expression and function of hemichannels, pannexons and GJCs in oligodendrocytes, as well as the evidence regarding the possible role of these channels in metabolic and synaptic functions at the CNS. In particular, we focus on oligodendrocyte-astrocyte coupling during axon metabolic support and its implications in brain health and disease.
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Affiliation(s)
- Sebastián Vejar
- Mechanisms of Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Juan E. Oyarzún
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mauricio A. Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Fernando C. Ortiz
- Mechanisms of Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes, Pontificia Universidad Católica de Chile, Santiago, Chile
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27
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Abudara V, Retamal MA, Del Rio R, Orellana JA. Synaptic Functions of Hemichannels and Pannexons: A Double-Edged Sword. Front Mol Neurosci 2018; 11:435. [PMID: 30564096 PMCID: PMC6288452 DOI: 10.3389/fnmol.2018.00435] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 11/08/2018] [Indexed: 01/18/2023] Open
Abstract
The classical view of synapses as the functional contact between presynaptic and postsynaptic neurons has been challenged in recent years by the emerging regulatory role of glial cells. Astrocytes, traditionally considered merely supportive elements are now recognized as active modulators of synaptic transmission and plasticity at the now so-called "tripartite synapse." In addition, an increasing body of evidence indicates that beyond immune functions microglia also participate in various processes aimed to shape synaptic plasticity. Release of neuroactive compounds of glial origin, -process known as gliotransmission-, constitute a widespread mechanism through which glial cells can either potentiate or reduce the synaptic strength. The prevailing vision states that gliotransmission depends on an intracellular Ca2+/exocytotic-mediated release; notwithstanding, growing evidence is pointing at hemichannels (connexons) and pannexin channels (pannexons) as alternative non-vesicular routes for gliotransmitters efflux. In concurrence with this novel concept, both hemichannels and pannexons are known to mediate the transfer of ions and signaling molecules -such as ATP and glutamate- between the cytoplasm and the extracellular milieu. Importantly, recent reports show that glial hemichannels and pannexons are capable to perceive synaptic activity and to respond to it through changes in their functional state. In this article, we will review the current information supporting the "double edge sword" role of hemichannels and pannexons in the function of central and peripheral synapses. At one end, available data support the idea that these channels are chief components of a feedback control mechanism through which gliotransmitters adjust the synaptic gain in either resting or stimulated conditions. At the other end, we will discuss how the excitotoxic release of gliotransmitters and [Ca2+]i overload linked to the opening of hemichannels/pannexons might impact cell function and survival in the nervous system.
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Affiliation(s)
- Verónica Abudara
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay
| | - Mauricio A Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile.,Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States.,Programa de Comunicación Celular en Cáncer, Instituto de Ciencias e Innovación en Medicina, Santiago, Chile
| | - Rodrigo Del Rio
- Laboratory of Cardiorespiratory Control, Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Envejecimiento y Regeneración, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Excelencia en Biomedicina de Magallanes, Universidad de Magallanes, Punta Arenas, Chile
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes, Santiago, Chile
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28
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Papaneophytou CP, Georgiou E, Karaiskos C, Sargiannidou I, Markoullis K, Freidin MM, Abrams CK, Kleopa KA. Regulatory role of oligodendrocyte gap junctions in inflammatory demyelination. Glia 2018; 66:2589-2603. [PMID: 30325069 PMCID: PMC6519212 DOI: 10.1002/glia.23513] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/20/2018] [Accepted: 06/25/2018] [Indexed: 12/27/2022]
Abstract
Gap junctions (GJs) coupling oligodendrocytes to astrocytes and to other oligodendrocytes are formed mainly by connexin47 (Cx47) and a smaller portion by connexin32 (Cx32). Mutations in both connexins cause inherited demyelinating disorders, but their expression is also disrupted in multiple sclerosis (MS). To clarify whether the loss of either Cx47 or Cx32 could modify the outcome of inflammation and myelin loss, we induced experimental autoimmune encephalomyelitis (EAE) in fully backcrossed Cx32 knockout (KO) and Cx47KO mice and compared their outcome with wild type (WT, C57BI/6 N) mice. Cx47KO EAE mice developed the most severe phenotype assessed by clinical scores and behavioral testing, followed by Cx32KO and WT mice. Cx47KO more than Cx32KO EAE mice developed more microglial activation, myelin, and axonal loss than did WT mice. Oligodendrocyte apoptosis and precursor proliferation was also higher in Cx47KO than in Cx32KO or WT EAE mice. Similarly, blood-spinal cord barrier (BSCB) disruption and inflammatory infiltrates of macrophages, T- and B-cells were more severe in Cx47KO than either Cx32KO or WT EAE groups. Finally, expression profiling revealed that several proinflammatory cytokines were higher at the peak of inflammation in the Cx47KO mice and persisted at later stages of EAE in contrast to reduction of their levels in WT EAE mice. Thus, loss of oligodendrocyte GJs aggravates BSCB disruption and inflammatory myelin loss, likely due to dysregulation of proinflammatory cytokines. This mechanism may play an important role in MS brain with reduced connexin expression, as well as in patients with inherited mutations in oligodendrocyte connexins and secondary inflammation.
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MESH Headings
- Animals
- Apoptosis/genetics
- Astrocytes/metabolism
- Astrocytes/pathology
- Blood-Brain Barrier/drug effects
- Blood-Brain Barrier/physiopathology
- Calcium-Binding Proteins/metabolism
- Cell Proliferation/genetics
- Connexins/genetics
- Connexins/metabolism
- Cytokines/metabolism
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/chemically induced
- Encephalomyelitis, Autoimmune, Experimental/genetics
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Encephalomyelitis, Autoimmune, Experimental/physiopathology
- Freund's Adjuvant/toxicity
- Gap Junctions/metabolism
- Gap Junctions/pathology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/genetics
- Gene Expression Regulation/physiology
- Hand Strength/physiology
- Macrophages/pathology
- Mice
- Mice, Inbred C57BL
- Microfilament Proteins/metabolism
- Motor Activity/drug effects
- Motor Activity/genetics
- Myelin-Oligodendrocyte Glycoprotein/toxicity
- Oligodendroglia/metabolism
- Oligodendroglia/pathology
- Peptide Fragments/toxicity
- Gap Junction beta-1 Protein
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Affiliation(s)
- Christos P. Papaneophytou
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
- Department of Life and Health Sciences, School of Sciences and EngineeringUniversity of NicosiaNicosiaCyprus
| | - Elena Georgiou
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Christos Karaiskos
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Irene Sargiannidou
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Kyriaki Markoullis
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
| | - Mona M. Freidin
- Department of Neurology and RehabilitationUniversity of Illinois ChicagoChicagoIllinois
| | - Charles K. Abrams
- Department of Neurology and RehabilitationUniversity of Illinois ChicagoChicagoIllinois
| | - Kleopas A. Kleopa
- Neuroscience LaboratoryThe Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular MedicineNicosiaCyprus
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29
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Fasciani I, Pluta P, González-Nieto D, Martínez-Montero P, Molano J, Paíno CL, Millet O, Barrio LC. Directional coupling of oligodendrocyte connexin-47 and astrocyte connexin-43 gap junctions. Glia 2018; 66:2340-2352. [PMID: 30144323 DOI: 10.1002/glia.23471] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 05/21/2018] [Accepted: 05/22/2018] [Indexed: 12/15/2022]
Abstract
Intercellular communication via gap junction channels between oligodendrocytes and between astrocytes as well as between these cell types is essential to maintain the integrity of myelin in the central nervous system. Oligodendrocyte gap junction connexin-47 (Cx47) is a key element in this crosstalk and indeed, mutations in human Cx47 cause severe myelin disorders. However, the permeation properties of channels of Cx47 alone and in heterotypic combination with astrocyte Cx43 remain unclear. We show here that Cx47 contains three extra residues at 5' amino-terminus that play a critical role in the channel pore structure and account for relative low ionic conductivity, cationic permselectivity and voltage-gating properties of oligodendrocyte-oligodendrocyte Cx47 channels. Regarding oligodendrocyte-astrocyte coupling, heterotypic channels formed by Cx47 with Cx43 exhibit ionic and chemical rectification, which creates a directional diffusion barrier for the movement of ions and larger negatively charged molecules from cells expressing Cx47 to those with Cx43. The restrictive permeability of Cx47 channels and the diffusion barrier of Cx47-Cx43 channels was abolished by a mutation associated with leukodystrophy, the Cx47P90S, suggesting a novel pathogenic mechanism underlying myelin disorders that involves alterations in the panglial permeation.
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Affiliation(s)
- Ilaria Fasciani
- Unit of Experimental Neurology and Neurobiology, "Ramón y Cajal" Hospital-IRYCIS, Carretera de Colmenar km 9, Madrid, 28034, Spain
| | - Paula Pluta
- Structural Biology Unit of CIC bioGUNE, Bizkaia Technology Park, Building 800, Derio, 48160, Spain
| | - Daniel González-Nieto
- Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), 28040 Madrid, and Center for Biomedical Technology, Universidad Politécnica de Madrid, Campus de Montegancedo S/N, Pozuelo de Alarcón, Madrid, 28223, Spain
| | - Paloma Martínez-Montero
- Unit of Molecular Genetics-INGEMM, Hospital "La Paz"-IDIPAZ, Paseo de la Castellana 261, 28046-Madrid, Spain
| | - Jesús Molano
- Unit of Molecular Genetics-INGEMM, Hospital "La Paz"-IDIPAZ, Paseo de la Castellana 261, 28046-Madrid, Spain
| | - Carlos L Paíno
- Unit of Experimental Neurology and Neurobiology, "Ramón y Cajal" Hospital-IRYCIS, Carretera de Colmenar km 9, Madrid, 28034, Spain
| | - Oscar Millet
- Structural Biology Unit of CIC bioGUNE, Bizkaia Technology Park, Building 800, Derio, 48160, Spain
| | - Luis C Barrio
- Unit of Experimental Neurology and Neurobiology, "Ramón y Cajal" Hospital-IRYCIS, Carretera de Colmenar km 9, Madrid, 28034, Spain
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30
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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31
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 1076] [Impact Index Per Article: 153.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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32
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Leferink PS, Heine VM. The Healthy and Diseased Microenvironments Regulate Oligodendrocyte Properties: Implications for Regenerative Medicine. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 188:39-52. [PMID: 29024633 DOI: 10.1016/j.ajpath.2017.08.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 07/12/2017] [Accepted: 08/01/2017] [Indexed: 02/08/2023]
Abstract
White matter disorders are characterized by deficient myelin or myelin loss, lead to a range of neurologic dysfunctions, and can result in early death. Oligodendrocytes, which are responsible for white matter formation, are the first targets for treatment. However, many studies indicate that failure of white matter repair goes beyond the intrinsic incapacity of oligodendrocytes to (re)generate myelin and that failed interactions with neighboring cells or factors in the diseased microenvironment can underlie white matter defects. Moreover, most of the white matter disorders show specific white matter pathology caused by different disease mechanisms. Herein, we review the factors within the cellular and the extracellular microenvironment regulating oligodendrocyte properties and discuss stem cell tools to identify microenvironmental factors of importance to the development of improved regenerative medicine for patients with white matter disorders.
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Affiliation(s)
- Prisca S Leferink
- Department of Pediatrics/Child Neurology, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Vivi M Heine
- Department of Pediatrics/Child Neurology, VU University Medical Center, Amsterdam Neuroscience, Amsterdam, the Netherlands; Department of Complex Trait Genetics, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
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33
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Roy S, Kim D, Lim R. Cell-cell communication in diabetic retinopathy. Vision Res 2017; 139:115-122. [PMID: 28583293 DOI: 10.1016/j.visres.2017.04.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 10/19/2022]
Abstract
In diabetic retinopathy, high glucose (HG)-mediated breakdown in cell-cell communication promotes disruption of retinal homeostasis. Several studies indicate that HG condition alters expression of connexin genes and subsequent gap junction intercellular communication (GJIC) in retinal vascular cells and non-vascular cells. A serious consequence of disrupted cell-cell communication is apoptosis and breakdown of the blood-retinal barrier (BRB). More recently, studies suggest adverse effects from HG on retinal Müller cells. This article focuses on HG-mediated changes in connexin expression and GJIC and their subsequent effects on the breakdown of retinal homeostasis, cell death, compromised vascular permeability, and interactions between endothelial cells, pericytes and retinal Müller cells in the pathogenesis of diabetic retinopathy. Additionally, options for rectifying disrupted homeostasis under HG condition associated with diabetic retinopathy are reviewed.
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Affiliation(s)
- Sayon Roy
- Department of Medicine and Ophthalmology, Boston University School of Medicine, Boston, MA, United States.
| | - Dongjoon Kim
- Department of Medicine and Ophthalmology, Boston University School of Medicine, Boston, MA, United States
| | - Remington Lim
- Department of Medicine and Ophthalmology, Boston University School of Medicine, Boston, MA, United States
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Basu R, Bose A, Thomas D, Das Sarma J. Microtubule-assisted altered trafficking of astrocytic gap junction protein connexin 43 is associated with depletion of connexin 47 during mouse hepatitis virus infection. J Biol Chem 2017; 292:14747-14763. [PMID: 28566289 DOI: 10.1074/jbc.m117.786491] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/16/2017] [Indexed: 11/06/2022] Open
Abstract
Gap junctions (GJs) are important for maintenance of CNS homeostasis. GJ proteins, connexin 43 (Cx43) and connexin 47 (Cx47), play a crucial role in production and maintenance of CNS myelin. Cx43 is mainly expressed by astrocytes in the CNS and forms gap junction intercellular communications between astrocytes-astrocytes (Cx43-Cx43) and between astrocytes-oligodendrocytes (Cx43-Cx47). Mutations of these connexin (Cx) proteins cause dysmyelinating diseases in humans. Previously, it has been shown that Cx43 localization and expression is altered due to mouse hepatitis virus (MHV)-A59 infection both in vivo and in vitro; however, its mechanism and association with loss of myelin protein was not elaborated. Thus, we explored potential mechanisms by which MHV-A59 infection alters Cx43 localization and examined the effects of viral infection on Cx47 expression and its association with loss of the myelin marker proteolipid protein. Immunofluorescence and total internal reflection fluorescence microscopy confirmed that MHV-A59 used microtubules (MTs) as a conduit to reach the cell surface and restricted MT-mediated Cx43 delivery to the cell membrane. Co-immunoprecipitation experiments demonstrated that Cx43-β-tubulin molecular interaction was depleted due to protein-protein interaction between viral particles and MTs. During acute MHV-A59 infection, oligodendrocytic Cx47, which is mainly stabilized by Cx43 in vivo, was down-regulated, and its characteristic staining remained disrupted even at chronic phase. The loss of Cx47 was associated with loss of proteolipid protein at the chronic stage of MHV-A59 infection.
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Affiliation(s)
- Rahul Basu
- From the Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, India
| | - Abhishek Bose
- From the Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, India
| | - Deepthi Thomas
- From the Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, India
| | - Jayasri Das Sarma
- From the Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur-741246, India
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35
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Georgiou E, Sidiropoulou K, Richter J, Papaneophytou C, Sargiannidou I, Kagiava A, von Jonquieres G, Christodoulou C, Klugmann M, Kleopa KA. Gene therapy targeting oligodendrocytes provides therapeutic benefit in a leukodystrophy model. Brain 2017; 140:599-616. [PMID: 28100454 PMCID: PMC5837386 DOI: 10.1093/brain/aww351] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 11/22/2016] [Accepted: 11/28/2016] [Indexed: 12/20/2022] Open
Abstract
Pelizaeus-Merzbacher-like disease or hypomyelinating leukodystrophy-2 is an autosomal recessively inherited leukodystrophy with childhood onset resulting from mutations in the gene encoding the gap junction protein connexin 47 (Cx47, encoded by GJC2). Cx47 is expressed specifically in oligodendrocytes and is crucial for gap junctional communication throughout the central nervous system. Previous studies confirmed that a cell autonomous loss-of-function mechanism underlies hypomyelinating leukodystrophy-2 and that transgenic oligodendrocyte-specific expression of another connexin, Cx32 (GJB1), can restore gap junctions in oligodendrocytes to achieve correction of the pathology in a disease model. To develop an oligodendrocyte-targeted gene therapy, we cloned the GJC2/Cx47 gene under the myelin basic protein promoter and used an adeno-associated viral vector (AAV.MBP.Cx47myc) to deliver the gene to postnatal Day 10 mice via a single intracerebral injection in the internal capsule area. Lasting Cx47 expression specifically in oligodendrocytes was detected in Cx47 single knockout and Cx32/Cx47 double knockout mice up to 12 weeks post-injection, including the corpus callosum and the internal capsule but also in more distant areas of the cerebrum and in the spinal cord. Application of this oligodendrocyte-targeted somatic gene therapy at postnatal Day 10 in groups of double knockout mice, a well characterized model of hypomyelinating leukodystrophy-2, resulted in significant improvement in motor performance and coordination at 1 month of age in treated compared to mock-treated mice, as well as prolonged survival. Furthermore, immunofluorescence and morphological analysis revealed improvement in demyelination, oligodendrocyte apoptosis, inflammation, and astrogliosis, all typical features of this leukodystrophy model in both brain and spinal cord. Functional dye transfer analysis confirmed the re-establishment of oligodendrocyte gap junctional connectivity in treated as opposed to untreated mice. These results provide a significant advance in the development of oligodendrocyte-cell specific gene therapy. Adeno-associated viral vectors can be used to target therapeutic expression of a myelin gene to oligodendrocytes. We show evidence for the first somatic gene therapy approach to treat hypomyelinating leukodystrophy-2 preclinically, providing a potential treatment for this and similar forms of leukodystrophies.
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Affiliation(s)
- Elena Georgiou
- 1 Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | | | - Jan Richter
- 3 Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Christos Papaneophytou
- 1 Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Irene Sargiannidou
- 1 Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Alexia Kagiava
- 1 Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Georg von Jonquieres
- 4 Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Christina Christodoulou
- 3 Department of Molecular Virology, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Matthias Klugmann
- 4 Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Kleopas A. Kleopa
- 1 Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
- 5 Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
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36
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Th1 cells downregulate connexin 43 gap junctions in astrocytes via microglial activation. Sci Rep 2016; 6:38387. [PMID: 27929069 PMCID: PMC5143974 DOI: 10.1038/srep38387] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 11/08/2016] [Indexed: 11/28/2022] Open
Abstract
We previously reported early and extensive loss of astrocytic connexin 43 (Cx43) in acute demyelinating lesions of multiple sclerosis (MS) patients. Because it is widely accepted that autoimmune T cells initiate MS lesions, we hypothesized that infiltrating T cells affect Cx43 expression in astrocytes, which contributes to MS lesion formation. Primary mixed glial cell cultures were prepared from newborn mouse brains, and microglia were isolated by anti-CD11b antibody-conjugated magnetic beads. Next, we prepared astrocyte-rich cultures and astrocyte/microglia-mixed cultures. Treatment of primary mixed glial cell cultures with interferon (IFN) γ, interleukin (IL)-4, or IL-17 showed that only IFNγ or IL-17 at high concentrations reduced Cx43 protein levels. Upon treatment of astrocyte-rich cultures and astrocyte/microglia-mixed cultures with IFNγ, Cx43 mRNA/protein levels and the function of gap junctions were reduced only in astrocyte/microglia-mixed cultures. IFNγ-treated microglia-conditioned media and IL-1β, which was markedly increased in IFNγ-treated microglia-conditioned media, reduced Cx43 protein levels in astrocyte-rich cultures. Finally, we confirmed that Th1 cell-conditioned medium decreased Cx43 protein levels in mixed glial cell cultures. These findings suggest that Th1 cell-derived IFNγ activates microglia to release IL-1β that reduces Cx43 gap junctions in astrocytes. Thus, Th1-dominant inflammatory states disrupt astrocytic intercellular communication and may exacerbate MS.
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37
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Olympiou M, Sargiannidou I, Markoullis K, Karaiskos C, Kagiava A, Kyriakoudi S, Abrams CK, Kleopa KA. Systemic inflammation disrupts oligodendrocyte gap junctions and induces ER stress in a model of CNS manifestations of X-linked Charcot-Marie-Tooth disease. Acta Neuropathol Commun 2016; 4:95. [PMID: 27585976 PMCID: PMC5009701 DOI: 10.1186/s40478-016-0369-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 08/17/2016] [Indexed: 11/10/2022] Open
Abstract
X-linked Charcot-Marie-Tooth disease (CMT1X) is a common form of inherited neuropathy resulting from different mutations affecting the gap junction (GJ) protein connexin32 (Cx32). A subset of CMT1X patients may additionally present with acute fulminant CNS dysfunction, typically triggered by conditions of systemic inflammation and metabolic stress. To clarify the underlying mechanisms of CNS phenotypes in CMT1X we studied a mouse model of systemic inflammation induced by lipopolysaccharide (LPS) injection to compare wild type (WT), connexin32 (Cx32) knockout (KO), and KO T55I mice expressing the T55I Cx32 mutation associated with CNS phenotypes. Following a single intraperitoneal LPS or saline (controls) injection at the age of 40-60 days systemic inflammatory response was documented by elevated TNF-α and IL-6 levels in peripheral blood and mice were evaluated 1 week after injection. Behavioral analysis showed graded impairment of motor performance in LPS treated mice, worse in KO T55I than in Cx32 KO and in Cx32 KO worse than WT. Iba1 immunostaining revealed widespread inflammation in LPS treated mice with diffusely activated microglia throughout the CNS. Immunostaining for the remaining major oligodendrocyte connexin Cx47 and for its astrocytic partner Cx43 revealed widely reduced expression of Cx43 and loss of Cx47 GJs in oligodendrocytes. Real-time PCR and immunoblot analysis indicated primarily a down regulation of Cx43 expression with secondary loss of Cx47 membrane localization. Inflammatory changes and connexin alterations were most severe in the KO T55I group. To examine why the presence of the T55I mutant exacerbates pathology even more than in Cx32 KO mice, we analyzed the expression of ER-stress markers BiP, Fas and CHOP by immunostaining, immunoblot and Real-time PCR. All markers were increased in LPS treated KO T55I mice more than in other genotypes. In conclusion, LPS induced neuroinflammation causes disruption of the main astrocyte-oligodendrocyte GJs, which may contribute to the increased sensitivity of Cx32 KO mice to LPS and of patients with CMT1X to various stressors. Moreover the presence of an intracellularly retained, misfolded CMT1X mutant such as T55I induces ER stress under inflammatory conditions, further exacerbating oligodendrocyte dysfunction and pathological changes in the CNS.
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Affiliation(s)
- Margarita Olympiou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Irene Sargiannidou
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Kyriaki Markoullis
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Christos Karaiskos
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Alexia Kagiava
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Styliana Kyriakoudi
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus
| | - Charles K Abrams
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, USA
| | - Kleopas A Kleopa
- Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, Nicosia, Cyprus.
- Neurology Clinics, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine, 6 International Airport Avenue, P.O. Box 23462, , 1683, Nicosia, Cyprus.
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38
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Abstract
Connexins and pannexins share very similar structures and functions; they also exhibit overlapping expression in many stages of neuronal development. Here, we review evidence implicating connexin- and pannexin-mediated communication in the regulation of the birth and development of neurons, specifically Cx26, Cx30, Cx32, Cx36, Cx43, Cx45, Panx1, and Panx2. We begin by dissecting the involvement of these proteins in the generation and development of new neurons in the embryonic, postnatal, and adult brain. Next we briefly outline common mechanisms employed by both pannexins and connexins in these roles, including modulation of purinergic receptor signalling and signalling nexus functions. Throughout this review we highlight developing themes as well as important gaps in knowledge to be bridged.
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Affiliation(s)
- Leigh Anne Swayne
- />Division of Medical Sciences, University of Victoria, Medical Sciences Building Rm 224, 3800 Finnerty Rd, Victoria, BC V8P5C2 Canada
| | - Steffany A. L. Bennett
- />Department of Biochemistry, Microbiology and Immunology, Neural Regeneration Laboratory, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON Canada
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39
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Rash JE, Vanderpool KG, Yasumura T, Hickman J, Beatty JT, Nagy JI. KV1 channels identified in rodent myelinated axons, linked to Cx29 in innermost myelin: support for electrically active myelin in mammalian saltatory conduction. J Neurophysiol 2016; 115:1836-59. [PMID: 26763782 PMCID: PMC4869480 DOI: 10.1152/jn.01077.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 01/04/2016] [Indexed: 11/22/2022] Open
Abstract
Saltatory conduction in mammalian myelinated axons was thought to be well understood before recent discoveries revealed unexpected subcellular distributions and molecular identities of the K(+)-conductance pathways that provide for rapid axonal repolarization. In this study, we visualize, identify, localize, quantify, and ultrastructurally characterize axonal KV1.1/KV1.2 channels in sciatic nerves of rodents. With the use of light microscopic immunocytochemistry and freeze-fracture replica immunogold labeling electron microscopy, KV1.1/KV1.2 channels are localized to three anatomically and compositionally distinct domains in the internodal axolemmas of large myelinated axons, where they form densely packed "rosettes" of 9-nm intramembrane particles. These axolemmal KV1.1/KV1.2 rosettes are precisely aligned with and ultrastructurally coupled to connexin29 (Cx29) channels, also in matching rosettes, in the surrounding juxtaparanodal myelin collars and along the inner mesaxon. As >98% of transmembrane proteins large enough to represent ion channels in these specialized domains, ∼500,000 KV1.1/KV1.2 channels define the paired juxtaparanodal regions as exclusive membrane domains for the voltage-gated K(+)conductance that underlies rapid axonal repolarization in mammals. The 1:1 molecular linkage of KV1 channels to Cx29 channels in the apposed juxtaparanodal collars, plus their linkage to an additional 250,000-400,000 Cx29 channels along each inner mesaxon in every large-diameter myelinated axon examined, supports previously proposed K(+)conductance directly from juxtaparanodal axoplasm into juxtaparanodal myeloplasm in mammalian axons. With neither Cx29 protein nor myelin rosettes detectable in frog myelinated axons, these data showing axon-to-myelin linkage by abundant KV1/Cx29 channels in rodent axons support renewed consideration of an electrically active role for myelin in increasing both saltatory conduction velocity and maximum propagation frequency in mammalian myelinated axons.
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Affiliation(s)
- John E Rash
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado; Program in Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, Colorado; and
| | - Kimberly G Vanderpool
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Thomas Yasumura
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Jordan Hickman
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Jonathan T Beatty
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - James I Nagy
- Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
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40
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Connexin43 in retinal injury and disease. Prog Retin Eye Res 2016; 51:41-68. [DOI: 10.1016/j.preteyeres.2015.09.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/25/2015] [Accepted: 09/27/2015] [Indexed: 12/26/2022]
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41
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Fowler S, Akins M, Bennett SAL. Preparation of Gap Junctions in Membrane Microdomains for Immunoprecipitation and Mass Spectrometry Interactome Analysis. Methods Mol Biol 2016; 1437:113-32. [PMID: 27207290 DOI: 10.1007/978-1-4939-3664-9_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Protein interaction networks at gap junction plaques are increasingly implicated in a variety of intracellular signaling cascades. Identifying protein interactions of integral membrane proteins is a valuable tool for determining channel function. However, several technical challenges exist. Subcellular fractionation of the bait protein matrix is usually required to identify less abundant proteins in complex homogenates. Sufficient solvation of the lipid environment without perturbation of the protein interactome must also be achieved. The present chapter describes the flotation of light and heavy liver tissue membrane microdomains to facilitate the identification and analysis of endogenous gap junction proteins and includes technical notes for translation to other integral membrane proteins, tissues, or cell culture models. These procedures are valuable tools for the enrichment of gap junction membrane compartments and for the identification of gap junction signaling interactomes.
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Affiliation(s)
- Stephanie Fowler
- Neural Regeneration Laboratory, Ottawa Institute of Systems Biology, Centre for Catalysis Research and Innovation, Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON, Canada.
| | - Mark Akins
- Neural Regeneration Laboratory, Ottawa Institute of Systems Biology, Centre for Catalysis Research and Innovation, Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Steffany A L Bennett
- Neural Regeneration Laboratory, Ottawa Institute of Systems Biology, Centre for Catalysis Research and Innovation, Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON, Canada
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42
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Abrams CK, Freidin M. GJB1-associated X-linked Charcot-Marie-Tooth disease, a disorder affecting the central and peripheral nervous systems. Cell Tissue Res 2015; 360:659-73. [PMID: 25370202 DOI: 10.1007/s00441-014-2014-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 09/22/2014] [Indexed: 11/24/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) is a group of inherited diseases characterized by exclusive or predominant involvement of the peripheral nervous system. Mutations in GJB1, the gene encoding Connexin 32 (Cx32), a gap-junction channel forming protein, cause the most common X-linked form of CMT, CMT1X. Cx32 is expressed in Schwann cells and oligodendrocytes, the myelinating glia of the peripheral and central nervous systems, respectively. Thus, patients with CMT1X have both central and peripheral nervous system manifestations. Study of the genetics of CMT1X and the phenotypes of patients with this disorder suggest that the peripheral manifestations of CMT1X are likely to be due to loss of function, while in the CNS gain of function may contribute. Mice with targeted ablation of Gjb1 develop a peripheral neuropathy similar to that seen in patients with CMT1X, supporting loss of function as a mechanism for the peripheral manifestations of this disorder. Possible roles for Cx32 include the establishment of a reflexive gap junction pathway in the peripheral and central nervous system and of a panglial syncitium in the central nervous system.
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Affiliation(s)
- Charles K Abrams
- Departments of Neurology and Physiology & Pharmacology, State University of New York, Brooklyn, NY, 11203, USA,
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43
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Masaki K. Early disruption of glial communication via connexin gap junction in multiple sclerosis, Baló's disease and neuromyelitis optica. Neuropathology 2015; 35:469-80. [DOI: 10.1111/neup.12211] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/09/2015] [Indexed: 12/17/2022]
Affiliation(s)
- Katsuhisa Masaki
- Department of Neurology; Neurological Institute; Graduate School of Medical Sciences; Kyushu University; Fukuoka Japan
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44
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Schiza N, Sargiannidou I, Kagiava A, Karaiskos C, Nearchou M, Kleopa KA. Transgenic replacement of Cx32 in gap junction-deficient oligodendrocytes rescues the phenotype of a hypomyelinating leukodystrophy model. Hum Mol Genet 2015; 24:2049-64. [PMID: 25524707 DOI: 10.1093/hmg/ddu725] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Oligodendrocytes are coupled by gap junctions (GJs) formed mainly by connexin47 (Cx47) and Cx32. Recessive GJC2/Cx47 mutations cause Pelizaeus-Merzbacher-like disease, a hypomyelinating leukodystrophy, while GJB1/Cx32 mutations cause neuropathy and chronic or acute-transient encephalopathy syndromes. Cx32/Cx47 double knockout (Cx32/Cx47dKO) mice develop severe CNS demyelination beginning at 1 month of age leading to death within weeks, offering a relevant model to study disease mechanisms. In order to clarify whether the loss of oligodendrocyte connexins has cell autonomous effects, we generated transgenic mice expressing the wild-type human Cx32 under the control of the mouse proteolipid protein promoter, obtaining exogenous hCx32 expression in oligodendrocytes. By crossing these mice with Cx32KO mice, we obtained expression of hCx32 on Cx32KO background. Immunohistochemical and immunoblot analysis confirmed strong CNS expression of hCx32 specifically in oligodendrocytes and correct localization forming GJs at cell bodies and along the myelin sheath. TG(+)Cx32/Cx47dKO mice generated by further crossing with Cx47KO mice showed that transgenic expression of hCx32 rescued the severe early phenotype of CNS demyelination in Cx32/Cx47dKO mice, resulting in marked improvement of behavioral abnormalities at 1 month of age, and preventing the early mortality. Furthermore, TG(+)Cx32/Cx47dKO mice showed significant improvement of myelination compared with Cx32/Cx47dKO CNS at 1 month of age, while the inflammatory and astrogliotic changes were fully reversed. Our study confirms that loss of oligodendrocyte GJs has cell autonomous effects and that re-establishment of GJ connectivity by replacement of least one GJ protein provides correction of the leukodystrophy phenotype.
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Affiliation(s)
| | | | | | | | - Marianna Nearchou
- Department of Molecular Pathology and Electron Microscopy, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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45
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Orr AG, Hsiao EC, Wang MM, Ho K, Kim DH, Wang X, Guo W, Kang J, Yu GQ, Adame A, Devidze N, Dubal DB, Masliah E, Conklin BR, Mucke L. Astrocytic adenosine receptor A2A and Gs-coupled signaling regulate memory. Nat Neurosci 2015; 18:423-34. [PMID: 25622143 PMCID: PMC4340760 DOI: 10.1038/nn.3930] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 12/15/2014] [Indexed: 01/18/2023]
Abstract
Astrocytes express a variety of G protein-coupled receptors and might influence cognitive functions, such as learning and memory. However, the roles of astrocytic Gs-coupled receptors in cognitive function are not known. We found that humans with Alzheimer's disease (AD) had increased levels of the Gs-coupled adenosine receptor A2A in astrocytes. Conditional genetic removal of these receptors enhanced long-term memory in young and aging mice and increased the levels of Arc (also known as Arg3.1), an immediate-early gene that is required for long-term memory. Chemogenetic activation of astrocytic Gs-coupled signaling reduced long-term memory in mice without affecting learning. Like humans with AD, aging mice expressing human amyloid precursor protein (hAPP) showed increased levels of astrocytic A2A receptors. Conditional genetic removal of these receptors enhanced memory in aging hAPP mice. Together, these findings establish a regulatory role for astrocytic Gs-coupled receptors in memory and suggest that AD-linked increases in astrocytic A2A receptor levels contribute to memory loss.
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MESH Headings
- Alzheimer Disease/pathology
- Animals
- Animals, Newborn
- Astrocytes/metabolism
- Cytoskeletal Proteins/genetics
- Cytoskeletal Proteins/metabolism
- Exploratory Behavior/drug effects
- Exploratory Behavior/physiology
- Gene Expression Regulation/physiology
- Glial Fibrillary Acidic Protein/genetics
- Glial Fibrillary Acidic Protein/metabolism
- Humans
- Indoles/pharmacology
- Maze Learning/physiology
- Memory, Long-Term/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Receptor, Adenosine A2A/genetics
- Receptor, Adenosine A2A/metabolism
- Receptors, Serotonin, 5-HT4/genetics
- Receptors, Serotonin, 5-HT4/metabolism
- Recognition, Psychology/drug effects
- Recognition, Psychology/physiology
- Serotonin Antagonists/pharmacology
- Signal Transduction/physiology
- Sulfonamides/pharmacology
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Affiliation(s)
- Anna G. Orr
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
| | - Edward C. Hsiao
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
- Division of Endocrinology and Metabolism, Department of Medicine, and the Institute for Human Genetics, University of California, San Francisco, CA 94158
| | - Max M. Wang
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Kaitlyn Ho
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Daniel H. Kim
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Xin Wang
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Weikun Guo
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Jing Kang
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Gui-Qiu Yu
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Anthony Adame
- Departments of Neuroscience and Pathology, University of California, San Diego, La Jolla, CA
| | - Nino Devidze
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
| | - Dena B. Dubal
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
| | - Eliezer Masliah
- Departments of Neuroscience and Pathology, University of California, San Diego, La Jolla, CA
| | - Bruce R. Conklin
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA 94158
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158
- Department of Neurology, University of California, San Francisco, CA 94158
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Genoud C, Houades V, Kraftsik R, Welker E, Giaume C. Proximity of excitatory synapses and astroglial gap junctions in layer IV of the mouse barrel cortex. Neuroscience 2015; 291:241-9. [PMID: 25681519 DOI: 10.1016/j.neuroscience.2015.01.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 12/27/2022]
Abstract
Neurons and astrocytes, the two major cell populations in the adult brain, are characterized by their own mode of intercellular communication--the synapses and the gap junctions (GJ), respectively. In addition, there is increasing evidence for dynamic and metabolic neuroglial interactions resulting in the modulation of synaptic transmission at the so-called "tripartite synapse". Based on this, we have investigated at the ultrastructural level how excitatory synapses (ES) and astroglial GJ are spatially distributed in layer IV of the barrel cortex of the adult mouse. We used specific antibodies for connexin (Cx) 30 and 43 to identify astroglial GJ, these two proteins are known to be present in the majority of astroglial GJ in the cerebral cortex. In electron-microscopic images, we measured the distance between two ES, between two GJ and between a GJ and its nearest ES. We found a ratio of two GJ per three ES in the hollow and septal areas. Taking into account the size of an astrocyte domain, the high density of GJ suggests the occurrence of reflexive type, i.e. GJ between processes of the same astrocyte. Interestingly, the distance between an ES and an astroglial GJ was found to be significantly lower than that between either two synapses or between two GJ. These observations indicate that the two modes of cell-to-cell communication are not randomly distributed in layer IV of the barrel cortex. Consequently, this feature may provide the morphological support for the recently reported functional interactions between neuronal circuits and astroglial networks.
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Affiliation(s)
- C Genoud
- Département de Neurosciences Fondamentales, University of Lausanne, 1005 Lausanne, Switzerland; Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - V Houades
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB), France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241, France; Institut National de la Santé et de la Recherche Médicale U1050, 75231 Paris Cedex 05, France; University Pierre et Marie Curie, ED, N°158, 75005 Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, 75005 Paris, France
| | - R Kraftsik
- Département de Neurosciences Fondamentales, University of Lausanne, 1005 Lausanne, Switzerland
| | - E Welker
- Département de Neurosciences Fondamentales, University of Lausanne, 1005 Lausanne, Switzerland.
| | - C Giaume
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB), France; Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241, France; Institut National de la Santé et de la Recherche Médicale U1050, 75231 Paris Cedex 05, France; University Pierre et Marie Curie, ED, N°158, 75005 Paris, France; MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, 75005 Paris, France.
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47
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Tonkin RS, Mao Y, O'Carroll SJ, Nicholson LFB, Green CR, Gorrie CA, Moalem-Taylor G. Gap junction proteins and their role in spinal cord injury. Front Mol Neurosci 2015; 7:102. [PMID: 25610368 PMCID: PMC4285056 DOI: 10.3389/fnmol.2014.00102] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 12/12/2014] [Indexed: 12/25/2022] Open
Abstract
Gap junctions are specialized intercellular communication channels that are formed by two hexameric connexin hemichannels, one provided by each of the two adjacent cells. Gap junctions and hemichannels play an important role in regulating cellular metabolism, signaling, and functions in both normal and pathological conditions. Following spinal cord injury (SCI), there is damage and disturbance to the neuronal elements of the spinal cord including severing of axon tracts and rapid cell death. The initial mechanical disruption is followed by multiple secondary cascades that cause further tissue loss and dysfunction. Recent studies have implicated connexin proteins as playing a critical role in the secondary phase of SCI by propagating death signals through extensive glial networks. In this review, we bring together past and current studies to outline the distribution, changes and roles of various connexins found in neurons and glial cells, before and in response to SCI. We discuss the contribution of pathologically activated connexin proteins, in particular connexin 43, to functional recovery and neuropathic pain, as well as providing an update on potential connexin specific pharmacological agents to treat SCI.
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Affiliation(s)
- Ryan S Tonkin
- School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia
| | - Yilin Mao
- School of Medical and Molecular Bioscience, Faculty of Science, University of Technology Sydney, NSW, Australia
| | - Simon J O'Carroll
- Department of Anatomy with Radiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland Auckland, New Zealand
| | - Louise F B Nicholson
- Department of Anatomy with Radiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology, Faculty of Medical and Health Sciences, University of Auckland Auckland, New Zealand
| | - Catherine A Gorrie
- School of Medical and Molecular Bioscience, Faculty of Science, University of Technology Sydney, NSW, Australia
| | - Gila Moalem-Taylor
- School of Medical Sciences, Faculty of Medicine, University of New South Wales Sydney, NSW, Australia
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48
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Oligodendrocyte gap junction loss and disconnection from reactive astrocytes in multiple sclerosis gray matter. J Neuropathol Exp Neurol 2014; 73:865-79. [PMID: 25101702 DOI: 10.1097/nen.0000000000000106] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Gap junctions are essential for glial cell function and have been increasingly implicated in multiple sclerosis (MS). Because increasing cortical abnormalities correlate with disease progression and cognitive dysfunction, we examined the expression of oligodendrocytic connexin32 (Cx32) and Cx47 and their astrocytic partners Cx30 and Cx43 in cortical lesions and normal-appearing gray matter (NAGM) in MS patients. Postmortem brain tissue samples from 9 MS cases were compared with 10 controls using real-time polymerase chain reaction, immunoblot, and immunohistochemical analyses. Connexin32 and Cx47 gap junction formation in oligodendrocytes was reduced within lesions, whereas Cx32 loss also extended to NAGM. In contrast, astrocytic Cx30 expression was increased within cortical lesions, whereas Cx43 was elevated in both lesions and NAGM. Diffuse microglial activation and marked astrogliotic changes accompanied these connexin abnormalities. Increased expression of Cx43 correlated with inflammatory load (r = 0.828, p = 0.042), whereas Cx32 expression correlated with longer disease duration and, therefore, milder course (r = 0.825, p = 0.043). Thus, there is a loss of intramyelin and intercellular oligodendrocyte gap junctions in MS gray matter lesions and NAGM, whereas interastrocytic gap junctions are increased, reflecting astrogliosis. These changes correlate with inflammation and disease duration and suggest that disconnection of oligodendrocytes from reactive astrocytes may play a role in failed remyelination and disease progression.
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Takeuchi H, Suzumura A. Gap junctions and hemichannels composed of connexins: potential therapeutic targets for neurodegenerative diseases. Front Cell Neurosci 2014; 8:189. [PMID: 25228858 PMCID: PMC4151093 DOI: 10.3389/fncel.2014.00189] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/19/2014] [Indexed: 12/03/2022] Open
Abstract
Microglia are macrophage-like resident immune cells that contribute to the maintenance of homeostasis in the central nervous system (CNS). Abnormal activation of microglia can cause damage in the CNS, and accumulation of activated microglia is a characteristic pathological observation in neurologic conditions such as trauma, stroke, inflammation, epilepsy, and neurodegenerative diseases. Activated microglia secrete high levels of glutamate, which damages CNS cells and has been implicated as a major cause of neurodegeneration in these conditions. Glutamate-receptor blockers and microglia inhibitors (e.g., minocycline) have been examined as therapeutic candidates for several neurodegenerative diseases; however, these compounds exerted little therapeutic benefit because they either perturbed physiological glutamate signals or suppressed the actions of protective microglia. The ideal therapeutic approach would hamper the deleterious roles of activated microglia without diminishing their protective effects. We recently found that abnormally activated microglia secrete glutamate via gap-junction hemichannels on the cell surface. Moreover, administration of gap-junction inhibitors significantly suppressed excessive microglial glutamate release and improved disease symptoms in animal models of neurologic conditions such as stroke, multiple sclerosis, amyotrophic lateral sclerosis, and Alzheimer's disease. Recent evidence also suggests that neuronal and glial communication via gap junctions amplifies neuroinflammation and neurodegeneration. Elucidation of the precise pathologic roles of gap junctions and hemichannels may lead to a novel therapeutic strategies that can slow and halt the progression of neurodegenerative diseases.
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Affiliation(s)
- Hideyuki Takeuchi
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University Nagoya, Japan
| | - Akio Suzumura
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University Nagoya, Japan
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Lieury A, Chanal M, Androdias G, Reynolds R, Cavagna S, Giraudon P, Confavreux C, Nataf S. Tissue remodeling in periplaque regions of multiple sclerosis spinal cord lesions. Glia 2014; 62:1645-58. [DOI: 10.1002/glia.22705] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 05/23/2014] [Accepted: 05/23/2014] [Indexed: 11/11/2022]
Affiliation(s)
- Alice Lieury
- INSERM U1028, CNRS UMR 5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team; Lyon France
- University Lyon 1; Lyon France
| | - Marie Chanal
- INSERM U1028, CNRS UMR 5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team; Lyon France
- University Lyon 1; Lyon France
| | - Géraldine Androdias
- INSERM U1028, CNRS UMR 5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team; Lyon France
- University Lyon 1; Lyon France
- Service de Neurologie A and Eugène Devic Foundation, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon (Lyon University Hospital); Bron France
| | - Richard Reynolds
- Wolfson Neuroscience Laboratories, Hammersmith Hospital Campus, Imperial College Faculty of Medicine; London United Kingdom
| | - Sylvie Cavagna
- INSERM U1028, CNRS UMR 5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team; Lyon France
| | - Pascale Giraudon
- INSERM U1028, CNRS UMR 5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team; Lyon France
| | - Christian Confavreux
- INSERM U1028, CNRS UMR 5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team; Lyon France
- University Lyon 1; Lyon France
- Service de Neurologie A and Eugène Devic Foundation, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon (Lyon University Hospital); Bron France
| | - Serge Nataf
- INSERM U1028, CNRS UMR 5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team; Lyon France
- University Lyon 1; Lyon France
- Banque de Cellules et de Tissus, Hôpital Edouard Herriot, Hospices Civils de Lyon (Lyon University Hospital); Lyon France
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