1
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Takase EO, Yamasaki R, Nagata S, Watanabe M, Masaki K, Yamaguchi H, Kira JI, Takeuchi H, Isobe N. Astroglial connexin 43 is a novel therapeutic target for chronic multiple sclerosis model. Sci Rep 2024; 14:10877. [PMID: 38740862 DOI: 10.1038/s41598-024-61508-2] [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: 10/29/2023] [Accepted: 05/07/2024] [Indexed: 05/16/2024] Open
Abstract
In chronic stages of multiple sclerosis (MS) and its animal model, experimental autoimmune encephalitis (EAE), connexin (Cx)43 gap junction channel proteins are overexpressed because of astrogliosis. To elucidate the role of increased Cx43, the central nervous system (CNS)-permeable Cx blocker INI-0602 was therapeutically administered. C57BL6 mice with chronic EAE initiated by MOG35-55 received INI-0602 (40 mg/kg) or saline intraperitoneally every other day from days post-immunization (dpi) 17-50. Primary astroglia were employed to observe calcein efflux responses. In INI-0602-treated mice, EAE clinical signs improved significantly in the chronic phase, with reduced demyelination and decreased CD3+ T cells, Iba-1+ and F4/80+ microglia/macrophages, and C3+GFAP+ reactive astroglia infiltration in spinal cord lesions. Flow cytometry analysis of CD4+ T cells from CNS tissues revealed significantly reduced Th17 and Th17/Th1 cells (dpi 24) and Th1 cells (dpi 50). Multiplex array of cerebrospinal fluid showed significantly suppressed IL-6 and significantly increased IL-10 on dpi 24 in INI-0602-treated mice, and significantly suppressed IFN-γ and MCP-1 on dpi 50 in the same group. In vitro INI-0602 treatment inhibited ATP-induced calcium propagations of Cx43+/+ astroglial cells to similar levels of those of Cx43-/- cells. Astroglial Cx43 hemichannels represent a novel therapeutic target for chronic EAE and MS.
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Affiliation(s)
- Ezgi Ozdemir Takase
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Ryo Yamasaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
| | - Satoshi Nagata
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Mitsuru Watanabe
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Katsuhisa Masaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Hiroo Yamaguchi
- School of Physical Therapy, Faculty of Rehabilitation, Reiwa Health Sciences University, Fukuoka, Japan
| | - Jun-Ichi Kira
- Translational Neuroscience Center, Graduate School of Medicine, and School of Pharmacy at Fukuoka, International University of Health and Welfare, Ookawa, Japan
- Department of Neurology, Brain and Nerve Center, Fukuoka Central Hospital, Fukuoka, Japan
| | - Hideyuki Takeuchi
- Department of Neurology and Stroke Medicine, Graduate School of Medicine, Yokohama City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
- Department of Neurology, Graduate School of Medicine, International University of Health and Welfare, Narita, Japan.
- Center for Intractable Neurological Diseases and Dementia, International University of Health and Welfare Atami Hospital, Atami, Japan.
| | - Noriko Isobe
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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2
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Astrocytes as Context for the Involvement of Myelin and Nodes of Ranvier in the Pathophysiology of Depression and Stress-Related Disorders. JOURNAL OF PSYCHIATRY AND BRAIN SCIENCE 2023; 8:e230001. [PMID: 36866235 PMCID: PMC9976698 DOI: 10.20900/jpbs.20230001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Astrocytes, despite some shared features as glial cells supporting neuronal function in gray and white matter, participate and adapt their morphology and neurochemistry in a plethora of distinct regulatory tasks in specific neural environments. In the white matter, a large proportion of the processes branching from the astrocytes' cell bodies establish contacts with oligodendrocytes and the myelin they form, while the tips of many astrocyte branches closely associate with nodes of Ranvier. Stability of myelin has been shown to greatly depend on astrocyte-to-oligodendrocyte communication, while the integrity of action potentials that regenerate at nodes of Ranvier has been shown to depend on extracellular matrix components heavily contributed by astrocytes. Several lines of evidence are starting to show that in human subjects with affective disorders and in animal models of chronic stress there are significant changes in myelin components, white matter astrocytes and nodes of Ranvier that have direct relevance to connectivity alterations in those disorders. Some of these changes involve the expression of connexins supporting astrocyte-to-oligodendrocyte gap junctions, extracellular matrix components produced by astrocytes around nodes of Ranvier, specific types of astrocyte glutamate transporters, and neurotrophic factors secreted by astrocytes that are involved in the development and plasticity of myelin. Future studies should further examine the mechanisms responsible for those changes in white matter astrocytes, their putative contribution to pathological connectivity in affective disorders, and the possibility of leveraging that knowledge to design new therapies for psychiatric disorders.
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Bernier LP, Brunner C, Cottarelli A, Balbi M. Location Matters: Navigating Regional Heterogeneity of the Neurovascular Unit. Front Cell Neurosci 2021; 15:696540. [PMID: 34276312 PMCID: PMC8277940 DOI: 10.3389/fncel.2021.696540] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 05/31/2021] [Indexed: 12/27/2022] Open
Abstract
The neurovascular unit (NVU) of the brain is composed of multiple cell types that act synergistically to modify blood flow to locally match the energy demand of neural activity, as well as to maintain the integrity of the blood-brain barrier (BBB). It is becoming increasingly recognized that the functional specialization, as well as the cellular composition of the NVU varies spatially. This heterogeneity is encountered as variations in vascular and perivascular cells along the arteriole-capillary-venule axis, as well as through differences in NVU composition throughout anatomical regions of the brain. Given the wide variations in metabolic demands between brain regions, especially those of gray vs. white matter, the spatial heterogeneity of the NVU is critical to brain function. Here we review recent evidence demonstrating regional specialization of the NVU between brain regions, by focusing on the heterogeneity of its individual cellular components and briefly discussing novel approaches to investigate NVU diversity.
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Affiliation(s)
- Louis-Philippe Bernier
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Clément Brunner
- Neuro-Electronics Research Flanders, Leuven, Belgium.,Vlaams Instituut voor Biotechnologie, Leuven, Belgium.,Interuniversity Microeletronics Centre, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | | | - Matilde Balbi
- Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
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4
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Richard C, Ruiz A, Cavagna S, Bigotte M, Vukusic S, Masaki K, Suenaga T, Kira JI, Giraudon P, Marignier R. Connexins in neuromyelitis optica: a link between astrocytopathy and demyelination. Brain 2021; 143:2721-2732. [PMID: 32889550 DOI: 10.1093/brain/awaa227] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/01/2020] [Accepted: 05/06/2020] [Indexed: 01/26/2023] Open
Abstract
Neuromyelitis optica, a rare neuroinflammatory demyelinating disease of the CNS, is characterized by the presence of specific pathogenic autoantibodies directed against the astrocytic water channel aquaporin 4 (AQP4) and is now considered as an astrocytopathy associated either with complement-dependent astrocyte death or with astrocyte dysfunction. However, the link between astrocyte dysfunction and demyelination remains unclear. We propose glial intercellular communication, supported by connexin hemichannels and gap junctions, to be involved in demyelination process in neuromyelitis optica. Using mature myelinated cultures, we demonstrate that a treatment of 1 h to 48 h with immunoglobulins purified from patients with neuromyelitis optica (NMO-IgG) is responsible for a complement independent demyelination, compared to healthy donors' immunoglobulins (P < 0.001). In parallel, patients' immunoglobulins induce an alteration of connexin expression characterized by a rapid loss of astrocytic connexins at the membrane followed by an increased size of gap junction plaques (+60%; P < 0.01). This was co-observed with connexin dysfunction with gap junction disruption (-57%; P < 0.001) and increased hemichannel opening (+17%; P < 0.001), associated with glutamate release. Blocking connexin 43 hemichannels with a specific peptide was able to prevent demyelination in co-treatment with patients compared to healthy donors' immunoglobulins. By contrast, the blockade of connexin 43 gap junctions with another peptide was detrimental for myelin (myelin density -48%; P < 0.001). Overall, our results suggest that dysregulation of connexins would play a pathogenetic role in neuromyelitis optica. The further identification of mechanisms leading to connexin dysfunction and soluble factors implicated, would provide interesting therapeutic strategies for demyelinating disorders.
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Affiliation(s)
- Chloé Richard
- INSERM U1028, CNRS UMR 5292, Lyon1 University, Center for Research in Neuroscience of Lyon, Lyon, France
| | - Anne Ruiz
- INSERM U1028, CNRS UMR 5292, Lyon1 University, Center for Research in Neuroscience of Lyon, Lyon, France
| | - Sylvie Cavagna
- INSERM U1028, CNRS UMR 5292, Lyon1 University, Center for Research in Neuroscience of Lyon, Lyon, France
| | - Maxime Bigotte
- INSERM U1028, CNRS UMR 5292, Lyon1 University, Center for Research in Neuroscience of Lyon, Lyon, France
| | - Sandra Vukusic
- Service de neurologie, sclérose en plaques, pathologies de la myéline et neuro-inflammation, Hôpital Neurologique Pierre Wertheimer Hospices Civils de Lyon, Lyon, France.,Centre de référence des maladies inflammatoires rares du cerveau et de la moelle, Lyon, France
| | - Katsuhisa Masaki
- Department of Neurology, Neurological institute, Graduate School of Medical Sciences, Kyushu University
| | | | - Jun-Ichi Kira
- Department of Neurology, Neurological institute, Graduate School of Medical Sciences, Kyushu University
| | - Pascale Giraudon
- INSERM U1028, CNRS UMR 5292, Lyon1 University, Center for Research in Neuroscience of Lyon, Lyon, France
| | - Romain Marignier
- INSERM U1028, CNRS UMR 5292, Lyon1 University, Center for Research in Neuroscience of Lyon, Lyon, France.,Service de neurologie, sclérose en plaques, pathologies de la myéline et neuro-inflammation, Hôpital Neurologique Pierre Wertheimer Hospices Civils de Lyon, Lyon, France.,Centre de référence des maladies inflammatoires rares du cerveau et de la moelle, Lyon, France
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5
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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: 3] [Impact Index Per Article: 0.8] [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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6
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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: 71] [Impact Index Per Article: 17.8] [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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7
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Xia CY, Xu JK, Pan CH, Lian WW, Yan Y, Ma BZ, He J, Zhang WK. Connexins in oligodendrocytes and astrocytes: Possible factors for demyelination in multiple sclerosis. Neurochem Int 2020; 136:104731. [PMID: 32201280 DOI: 10.1016/j.neuint.2020.104731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022]
Abstract
Increasing evidences support that glial connexins are involved in the demyelination pathology of multiple sclerosis (MS), a chronic inflammatory demyelinating disorder. Here, we review the data from patients with MS and animal models of MS that implicate connexins in demyelination. Connexins expressed in oligodendrocytes and astrocytes show diverse changes at the different phases of MS. Loss of oligodendrocyte or astrocyte connexins contributes to demyelination and exaggerates the pathology of MS. Channel-dependent and -independent connexins are involved in the pathology of demyelination, which is related with myelin integrity, metabolic homeostasis, the brain-blood barrier, the immune cell infiltration, and the inflammatory response. A comprehensive understanding of connexin function in demyelination may provide new therapeutic targets for MS.
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Affiliation(s)
- Cong-Yuan Xia
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Jie-Kun Xu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, People's Republic of China
| | - Chen-Hao Pan
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, People's Republic of China
| | - Wen-Wen Lian
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Yu Yan
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Bing-Zhi Ma
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Jun He
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China.
| | - Wei-Ku Zhang
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China.
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8
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Heterogeneity of Astrocytes in Grey and White Matter. Neurochem Res 2019; 46:3-14. [PMID: 31797158 DOI: 10.1007/s11064-019-02926-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 11/21/2019] [Accepted: 11/28/2019] [Indexed: 02/07/2023]
Abstract
Astrocytes are a diverse and heterogeneous type of glial cells. The major task of grey and white matter areas in the brain are computation of information at neuronal synapses and propagation of action potentials along axons, respectively, resulting in diverse demands for astrocytes. Adapting their function to the requirements in the local environment, astrocytes differ in morphology, gene expression, metabolism, and many other properties. Here we review the differential properties of protoplasmic astrocytes of grey matter and fibrous astrocytes located in white matter in respect to glutamate and energy metabolism, to their function at the blood-brain interface and to coupling via gap junctions. Finally, we discuss how this astrocytic heterogeneity might contribute to the different susceptibility of grey and white matter to ischemic insults.
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9
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Wang M, Qin C, Luo X, Wang J, Wang X, Xie M, Hu J, Cao J, Hu T, Goldman SA, Nedergaard M, Wang W. Astrocytic connexin 43 potentiates myelin injury in ischemic white matter disease. Am J Cancer Res 2019; 9:4474-4493. [PMID: 31285774 PMCID: PMC6599652 DOI: 10.7150/thno.31942] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 04/19/2019] [Indexed: 01/05/2023] Open
Abstract
Rational: Myelin loss is a characteristic feature of both ischemic white matter disease and its associated vascular dementia, and is a hallmark of chronic cerebral hypoperfusion due to carotid artery stenosis. Yet the cellular mechanisms involved in ischemic dysmyelination are not well-understood, and no effective treatment has emerged to prevent or slow hypoperfusion-related demyelination. In a study employing the bilateral common carotid artery stenosis (BCAS) mouse model, we found reduced cerebral blood flow velocity and arteriolar pulsatility, and confirmed that prolonged BCAS provoked myelin disruption. These pathological features were associated with marked cognitive decline, in the absence of evident damage to axons. Methods: To assess the role of astroglial communication in BCAS-associated demyelination, we investigated the effect of deleting or inhibiting connexin 43 (Cx43), a constituent of astroglial gap junctions and hemichannels. Results: Genetic deletion and pharmacological inhibition of gap junctions both protected myelin integrity and rescued cognitive decline in the BCAS-treated mice. Gap junction inhibition also suppressed the transient increase in extracellular glutamate observed in the callosal white matter of wild-type mice exposed to BCAS. Conclusion: These findings suggest that astrocytic Cx43 may be a viable target for attenuating the demyelination and cognitive decline associated with chronic cerebral hypoperfusion.
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10
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Bijland S, Thomson G, Euston M, Michail K, Thümmler K, Mücklisch S, Crawford CL, Barnett SC, McLaughlin M, Anderson TJ, Linington C, Brown ER, Kalkman ER, Edgar JM. An in vitro model for studying CNS white matter: functional properties and experimental approaches. F1000Res 2019; 8:117. [PMID: 31069065 PMCID: PMC6489523 DOI: 10.12688/f1000research.16802.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/15/2019] [Indexed: 12/23/2022] Open
Abstract
The normal development and maintenance of CNS white matter, and its responses to disease and injury, are defined by synergies between axons, oligodendrocytes, astrocytes and microglia, and further influenced by peripheral components such as the gut microbiome and the endocrine and immune systems. Consequently, mechanistic insights, therapeutic approaches and safety tests rely ultimately on in vivo models and clinical trials. However, in vitro models that replicate the cellular complexity of the CNS can inform these approaches, reducing costs and minimising the use of human material or experimental animals; in line with the principles of the 3Rs. Using electrophysiology, pharmacology, time-lapse imaging, and immunological assays, we demonstrate that murine spinal cord-derived myelinating cell cultures recapitulate spinal-like electrical activity and innate CNS immune functions, including responses to disease-relevant myelin debris and pathogen associated molecular patterns (PAMPs). Further, we show they are (i) amenable to siRNA making them suitable for testing gene-silencing strategies; (ii) can be established on microelectrode arrays (MEAs) for electrophysiological studies; and (iii) are compatible with multi-well microplate formats for semi-high throughput screens, maximising information output whilst further reducing animal use. We provide protocols for each of these. Together, these advances increase the utility of this in vitro tool for studying normal and pathological development and function of white matter, and for screening therapeutic molecules or gene targets for diseases such as multiple sclerosis, motor neuron disease or spinal cord injury, whilst avoiding in vivo approaches on experimental animals.
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Affiliation(s)
- Silvia Bijland
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Gemma Thomson
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Matthew Euston
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Kyriakos Michail
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Katja Thümmler
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Steve Mücklisch
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Colin L Crawford
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Susan C Barnett
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Mark McLaughlin
- School of Veterinary Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G61 1QH, UK
| | - T James Anderson
- School of Veterinary Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G61 1QH, UK
| | - Christopher Linington
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Euan R Brown
- Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Eric R Kalkman
- Institute of Cancer Sciences, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G61 1QH, UK
| | - Julia M Edgar
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
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11
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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: 4.0] [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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12
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Wang Q, Wang Z, Tian Y, Zhang H, Fang Y, Yu Z, Wang W, Xie M, Ding F. Inhibition of Astrocyte Connexin 43 Channels Facilitates the Differentiation of Oligodendrocyte Precursor Cells Under Hypoxic Conditions In Vitro. J Mol Neurosci 2018; 64:591-600. [PMID: 29623602 PMCID: PMC6763517 DOI: 10.1007/s12031-018-1061-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 03/06/2018] [Indexed: 12/15/2022]
Abstract
Oligodendrocyte precursor cells (OPCs) proliferation and differentiation are essential for remyelination after white matter injury. Astrocytes could promote oligodendrogenesis after white matter damage whereas the underlying mechanisms are unknown. In this study, the role of astrocytic connexin43 (Cx43) hemichannels involved in OPC proliferation and differentiation in chronic hypoxia was evaluated. In an astrocyte-OPC co-culture chronic hypoxia model, OPCs became proliferative but failed to mature into oligodendrocytes. Application of astrocytic Cx43 blockers attenuated astrocyte activation, suppressed Cx43 hemichannel uptake activity and glutamate release induced by hypoxia, as well as improved OPC differentiation. Moreover, AMPA but not NMDA glutamate receptor antagonist rescued OPC differentiation in hypoxia. In conclusion, these findings suggested that astrocytic Cx43 hemichannel inhibition could potentially improve OPC maturation by attenuating AMPAR-mediated glutamate signaling. Astrocytic Cx43 hemichannels could serve as a potential therapeutic target for remyelination after chronic hypoxia.
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Affiliation(s)
- Qiong Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Zhen Wang
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Yeye Tian
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Huaqiu Zhang
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Yongkang Fang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Zhiyuan Yu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.,Key Laboratory of Neurological Diseases of Chinese Ministry of Education, the School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Minjie Xie
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.,Key Laboratory of Neurological Diseases of Chinese Ministry of Education, the School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China
| | - Fengfei Ding
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People's Republic of China.
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13
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Ren Q, Wang ZZ, Chu SF, Xia CY, Chen NH. Gap junction channels as potential targets for the treatment of major depressive disorder. Psychopharmacology (Berl) 2018; 235:1-12. [PMID: 29178009 DOI: 10.1007/s00213-017-4782-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 11/05/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND Major depressive disorder (MDD) remains a major public health problem worldwide. The association between MDD and the dysfunction of gap junction channels (GJCs) in glial cells, especially astrocytes, is still controversial. OBJECTIVE This review provides an overview of the role of astrocyte GJCs in LMDD. RESULTS Exposure to chronic unpredictable stress caused a reduction in connexin expression in the rat prefrontal cortex, a result that is consistent with clinical findings reported in postmortem studies of brains from MDD patients. Chronic antidepressant treatment in these rats increased the expression of connexins. However, pharmacological GJC blockade in normal rodents decreased connexin expression and caused depressive-like behaviors. Furthermore, GJC dysfunction affects electrical conductance, metabolic coupling and secondary messengers, and inflammatory responses, which are consistent with current hypotheses on MDD. All these results provide a comprehensive overview of the neurobiology of MDD. CONCLUSION This review supports the hypothesis that the regulation of GJCs between astrocytes could be an underlying mechanism for the therapeutic effect of antidepressants.
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Affiliation(s)
- Qian Ren
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Shi-Feng Chu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Cong-Yuan Xia
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China. .,College of Pharmacy, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.
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14
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Alberto AVP, Bonavita AG, Fidalgo-Neto AA, Berçot F, Alves LA. Single-cell Microinjection for Cell Communication Analysis. J Vis Exp 2017. [PMID: 28287521 DOI: 10.3791/50836] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Gap junctions are intercellular channels that allow the communication of neighboring cells. This communication depends on the contribution of a hemichannel by each neighboring cell to form the gap junction. In mammalian cells, the hemichannel is formed by six connexins, monomers with four transmembrane domains and a C and N terminal within the cytoplasm. Gap junctions permit the exchange of ions, second messengers, and small metabolites. In addition, they have important roles in many forms of cellular communication within physiological processes such as synaptic transmission, heart contraction, cell growth and differentiation. We detail how to perform a single-cell microinjection of Lucifer Yellow to visualize cellular communication via gap-junctions in living cells. It is expected that in functional gap junctions, the dye will diffuse from the loaded cell to the connected cells. It is a very useful technique to study gap junctions since you can evaluate the diffusion of the fluorescence in real time. We discuss how to prepare the cells and the micropipette, how to use a micromanipulator and inject a low molecular weight fluorescent dye in an epithelial cell line.
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Affiliation(s)
| | - André G Bonavita
- Institute Oswaldo Cruz, Laboratory of Cellular Communication, Oswaldo Cruz Foundation
| | | | - Filipe Berçot
- Institute Oswaldo Cruz, Laboratory of Cellular Communication, Oswaldo Cruz Foundation
| | - Luiz A Alves
- Institute Oswaldo Cruz, Laboratory of Cellular Communication, Oswaldo Cruz Foundation;
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15
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Manjarrez-Marmolejo J, Franco-Pérez J. Gap Junction Blockers: An Overview of their Effects on Induced Seizures in Animal Models. Curr Neuropharmacol 2017; 14:759-71. [PMID: 27262601 PMCID: PMC5050393 DOI: 10.2174/1570159x14666160603115942] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 02/26/2016] [Accepted: 04/21/2016] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Gap junctions are clusters of intercellular channels allowing the bidirectional pass of ions directly into the cytoplasm of adjacent cells. Electrical coupling mediated by gap junctions plays a role in the generation of highly synchronized electrical activity. The hypersynchronous neuronal activity is a distinctive characteristic of convulsive events. Therefore, it has been postulated that enhanced gap junctional communication is an underlying mechanism involved in the generation and maintenance of seizures. There are some chemical compounds characterized as gap junction blockers because of their ability to disrupt the gap junctional intercellular communication. OBJECTIVE Hence, the aim of this review is to analyze the available data concerning the effects of gap junction blockers specifically in seizure models. RESULTS Carbenoxolone, quinine, mefloquine, quinidine, anandamide, oleamide, heptanol, octanol, meclofenamic acid, niflumic acid, flufenamic acid, glycyrrhetinic acid and retinoic acid have all been evaluated on animal seizure models. In vitro, these compounds share anticonvulsant effects typically characterized by the reduction of both amplitude and frequency of the epileptiform activity induced in brain slices. In vivo, gap junction blockers modify the behavioral parameters related to seizures induced by 4-aminopyridine, pentylenetetrazole, pilocarpine, penicillin and maximal electroshock. CONCLUSION Although more studies are still required, these molecules could be a promising avenue in the search for new pharmaceutical alternatives for the treatment of epilepsy.
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Affiliation(s)
| | - Javier Franco-Pérez
- Laboratory of Physiology of Reticular Formation, National Institute of Neurology and Neurosurgery, M.V.S. Insurgentes Sur 3877, Col. La Fama, C.P. 14269, Mexico D.F., Mexico
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16
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Schmidt K, Windler R, de Wit C. Communication Through Gap Junctions in the Endothelium. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 77:209-40. [PMID: 27451099 DOI: 10.1016/bs.apha.2016.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A swarm of fish displays a collective behavior (swarm behavior) and moves "en masse" despite the huge number of individual animals. In analogy, organ function is supported by a huge number of cells that act in an orchestrated fashion and this applies also to vascular cells along the vessel length. It is obvious that communication is required to achieve this vital goal. Gap junctions with their modular bricks, connexins (Cxs), provide channels that interlink the cytosol of adjacent cells by a pore sealed against the extracellular space. This allows the transfer of ions and charge and thereby the travel of membrane potential changes along the vascular wall. The endothelium provides a low-resistance pathway that depends crucially on connexin40 which is required for long-distance conduction of dilator signals in the microcirculation. The experimental evidence for membrane potential changes synchronizing vascular behavior is manifold but the functional verification of a physiologic role is still open. Other molecules may also be exchanged that possibly contribute to the synchronization (eg, Ca(2+)). Recent data suggest that vascular Cxs have more functions than just facilitating communication. As pharmacological tools to modulate gap junctions are lacking, Cx-deficient mice provide currently the standard to unravel their vascular functions. These include arteriolar dilation during functional hyperemia, hypoxic pulmonary vasoconstriction, vascular collateralization after ischemia, and feedback inhibition on renin secretion in the kidney.
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Affiliation(s)
- K Schmidt
- Institut für Physiologie, Universität zu Lübeck, Lübeck, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK) e.V. (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
| | - R Windler
- Institut für Physiologie, Universität zu Lübeck, Lübeck, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK) e.V. (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany
| | - C de Wit
- Institut für Physiologie, Universität zu Lübeck, Lübeck, Germany; Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK) e.V. (German Center for Cardiovascular Research), Partner Site Hamburg/Kiel/Lübeck, Lübeck, Germany.
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17
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Jeanson T, Pondaven A, Ezan P, Mouthon F, Charvériat M, Giaume C. Antidepressants Impact Connexin 43 Channel Functions in Astrocytes. Front Cell Neurosci 2016; 9:495. [PMID: 26778961 PMCID: PMC4703821 DOI: 10.3389/fncel.2015.00495] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/09/2015] [Indexed: 12/20/2022] Open
Abstract
Glial cells, and in particular astrocytes, are crucial to maintain neuronal microenvironment by regulating energy metabolism, neurotransmitter uptake, gliotransmission, and synaptic development. Moreover, a typical feature of astrocytes is their high expression level of connexins, a family of membrane proteins that form gap junction channels allowing intercellular exchanges and hemichannels that provide release and uptake pathways for neuroactive molecules. Interestingly, several studies have revealed unexpected changes in astrocytes from depressive patients and rodent models of depressive-like behavior. Moreover, changes in the expression level of the astroglial connexin 43 (Cx43) have been reported in a depressive context. On the other hand, antidepressive drugs have also been shown to impact the expression of this connexin in astrocytes. However, so far there is little information concerning the functional consequence of these changes, i.e., the status of gap junctional communication and hemichannel activity in astrocytes exposed to antidepressants. In the present work we focused our attention on the action of seven antidepressants from four different therapeutic classes and tested their effects on Cx43 expression and on the two connexin-based channels functions studied in cultured astrocytes. We here report that when used at non-toxic and clinically relevant concentrations they have no effects on Cx43 expression but differential effects on Cx43 gap junction channels. Moreover, all tested antidepressants inhibit Cx43 hemichannel with different efficiency depending on their therapeutic classe. By studying the impact of antidepressants on the functional status of astroglial connexin channels, contributing to dynamic neuroglial interactions, our observations should help to better understand the mechanism by which these drugs provide their effect in the brain.
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Affiliation(s)
- Tiffany Jeanson
- Collège de France, Center for Interdisciplinary Research in Biology/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050Paris, France; University Pierre et Marie CurieParis, France; MemoLife Laboratory of Excellence and Paris Science Lettre Research UniversityParis, France; TheranexusLyon, France
| | - Audrey Pondaven
- Collège de France, Center for Interdisciplinary Research in Biology/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050Paris, France; University Pierre et Marie CurieParis, France; MemoLife Laboratory of Excellence and Paris Science Lettre Research UniversityParis, France
| | - Pascal Ezan
- Collège de France, Center for Interdisciplinary Research in Biology/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050Paris, France; University Pierre et Marie CurieParis, France; MemoLife Laboratory of Excellence and Paris Science Lettre Research UniversityParis, France
| | | | | | - Christian Giaume
- Collège de France, Center for Interdisciplinary Research in Biology/Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241/Institut National de la Santé et de la Recherche Médicale U1050Paris, France; University Pierre et Marie CurieParis, France; MemoLife Laboratory of Excellence and Paris Science Lettre Research UniversityParis, France
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18
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Stout RF, Snapp EL, Spray DC. Connexin Type and Fluorescent Protein Fusion Tag Determine Structural Stability of Gap Junction Plaques. J Biol Chem 2015; 290:23497-514. [PMID: 26265468 DOI: 10.1074/jbc.m115.659979] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Indexed: 12/22/2022] Open
Abstract
Gap junctions (GJs) are made up of plaques of laterally clustered intercellular channels and the membranes in which the channels are embedded. Arrangement of channels within a plaque determines subcellular distribution of connexin binding partners and sites of intercellular signaling. Here, we report the discovery that some connexin types form plaque structures with strikingly different degrees of fluidity in the arrangement of the GJ channel subcomponents of the GJ plaque. We uncovered this property of GJs by applying fluorescence recovery after photobleaching to GJs formed from connexins fused with fluorescent protein tags. We found that connexin 26 (Cx26) and Cx30 GJs readily diffuse within the plaque structures, whereas Cx43 GJs remain persistently immobile for more than 2 min after bleaching. The cytoplasmic C terminus of Cx43 was required for stability of Cx43 plaque arrangement. We provide evidence that these qualitative differences in GJ arrangement stability reflect endogenous characteristics, with the caveat that the sizes of the GJs examined were necessarily large for these measurements. We also uncovered an unrecognized effect of non-monomerized fluorescent protein on the dynamically arranged GJs and the organization of plaques composed of multiple connexin types. Together, these findings redefine our understanding of the GJ plaque structure and should be considered in future studies using fluorescent protein tags to probe dynamics of highly ordered protein complexes.
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Affiliation(s)
- Randy F Stout
- From the Dominick P. Purpura Department of Neuroscience and
| | - Erik Lee Snapp
- the Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - David C Spray
- From the Dominick P. Purpura Department of Neuroscience and
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19
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Nicaise C, Mitrecic D, Falnikar A, Lepore AC. Transplantation of stem cell-derived astrocytes for the treatment of amyotrophic lateral sclerosis and spinal cord injury. World J Stem Cells 2015; 7:380-398. [PMID: 25815122 PMCID: PMC4369494 DOI: 10.4252/wjsc.v7.i2.380] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/07/2014] [Accepted: 11/19/2014] [Indexed: 02/06/2023] Open
Abstract
Neglected for years, astrocytes are now recognized to fulfill and support many, if not all, homeostatic functions of the healthy central nervous system (CNS). During neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and spinal cord injury (SCI), astrocytes in the vicinity of degenerating areas undergo both morphological and functional changes that might compromise their intrinsic properties. Evidence from human and animal studies show that deficient astrocyte functions or loss-of-astrocytes largely contribute to increased susceptibility to cell death for neurons, oligodendrocytes and axons during ALS and SCI disease progression. Despite exciting advances in experimental CNS repair, most of current approaches that are translated into clinical trials focus on the replacement or support of spinal neurons through stem cell transplantation, while none focus on the specific replacement of astroglial populations. Knowing the important functions carried out by astrocytes in the CNS, astrocyte replacement-based therapies might be a promising approach to alleviate overall astrocyte dysfunction, deliver neurotrophic support to degenerating spinal tissue and stimulate endogenous CNS repair abilities. Enclosed in this review, we gathered experimental evidence that argue in favor of astrocyte transplantation during ALS and SCI. Based on their intrinsic properties and according to the cell type transplanted, astrocyte precursors or stem cell-derived astrocytes promote axonal growth, support mechanisms and cells involved in myelination, are able to modulate the host immune response, deliver neurotrophic factors and provide protective molecules against oxidative or excitotoxic insults, amongst many possible benefits. Embryonic or adult stem cells can even be genetically engineered in order to deliver missing gene products and therefore maximize the chance of neuroprotection and functional recovery. However, before broad clinical translation, further preclinical data on safety, reliability and therapeutic efficiency should be collected. Although several technical challenges need to be overcome, we discuss the major hurdles that have already been met or solved by targeting the astrocyte population in experimental ALS and SCI models and we discuss avenues for future directions based on latest molecular findings regarding astrocyte biology.
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20
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Hirrlinger J, Nave KA. Adapting brain metabolism to myelination and long-range signal transduction. Glia 2014; 62:1749-61. [DOI: 10.1002/glia.22737] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 07/23/2014] [Accepted: 07/23/2014] [Indexed: 12/24/2022]
Affiliation(s)
- Johannes Hirrlinger
- Department of Neurogenetics; Max-Planck-Institute for Experimental Medicine; Göttingen Germany
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig; Leipzig Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics; Max-Planck-Institute for Experimental Medicine; Göttingen Germany
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21
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Miguel-Hidalgo JJ, Wilson BA, Hussain S, Meshram A, Rajkowska G, Stockmeier CA. Reduced connexin 43 immunolabeling in the orbitofrontal cortex in alcohol dependence and depression. J Psychiatr Res 2014; 55:101-9. [PMID: 24774648 PMCID: PMC4078739 DOI: 10.1016/j.jpsychires.2014.04.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/18/2014] [Accepted: 04/04/2014] [Indexed: 11/28/2022]
Abstract
Reduced density of glial cells and low levels of some astrocyte proteins have been described in the orbitofrontal cortex (OFC) in depression and alcoholism, two disorders often comorbid. These regressive changes may also involve the communication between astrocytes via gap junctions and hemichannels, which play important regulatory roles in neurotransmission. We determined levels and morphological immunostaining parameters of connexin 43 (Cx43), the main protein subunit of astrocyte gap junctions/hemichannels, in the OFC of subjects with depression, alcoholism or comorbid depression/alcoholism as compared to non-psychiatric subjects. Postmortem brain samples from 23 subjects with major depressive disorder (MDD), 16 with alcohol dependence, 13 with comorbid MDD and alcohol dependence, and 20 psychiatrically-normal comparison subjects were processed for western blots to determine Cx43 levels. Area fraction of Cx43 immunoreactivity, and density and average size of immunoreactive puncta were measured in histological sections. There was a significant, larger than 60 percent decrease in Cx43 level in the three psychiatric groups as compared to controls. Area fraction of immunoreactivity and immunoreactive punctum size were reduced in all psychiatric groups, but Cx43-immunoreactive puncta density was reduced only in alcohol-dependent subjects. Among psychiatric subjects, no difference in Cx43 levels or immunostaining was found between suicides and non-suicides. The present data suggest that dysfunction of the OFC is accompanied by reduction in the levels of gap junction protein Cx43 in depression and alcoholism, and reduction in density of Cx43 immunoreactive puncta only in alcoholism, pointing to altered gap junction or hemichannel-based communication in the pathophysiology of those disorders.
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Affiliation(s)
- José Javier Miguel-Hidalgo
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N. State Street, Jackson, MS 39216-4505, USA.
| | - Barbara A. Wilson
- Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS
| | - Syed Hussain
- Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS
| | - Ashish Meshram
- Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS
| | - Grazyna Rajkowska
- Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS
| | - Craig A. Stockmeier
- Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS,Psychiatry, Case Western Reserve University, Cleveland, OH
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22
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Koval M, Molina SA, Burt JM. Mix and match: investigating heteromeric and heterotypic gap junction channels in model systems and native tissues. FEBS Lett 2014; 588:1193-204. [PMID: 24561196 DOI: 10.1016/j.febslet.2014.02.025] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 02/12/2014] [Accepted: 02/13/2014] [Indexed: 12/12/2022]
Abstract
This review is based in part on a roundtable discussion session: "Physiological roles for heterotypic/heteromeric channels" at the 2013 International Gap Junction Conference (IGJC 2013) in Charleston, South Carolina. It is well recognized that multiple connexins can specifically co-assemble to form mixed gap junction channels with unique properties as a means to regulate intercellular communication. Compatibility determinants for both heteromeric and heterotypic gap junction channel formation have been identified and associated with specific connexin amino acid motifs. Hetero-oligomerization is also a regulated process; differences in connexin quality control and monomer stability are likely to play integral roles to control interactions between compatible connexins. Gap junctions in oligodendrocyte:astrocyte communication and in the cardiovascular system have emerged as key systems where heterotypic and heteromeric channels have unique physiologic roles. There are several methodologies to study heteromeric and heterotypic channels that are best applied to either heterologous expression systems, native tissues or both. There remains a need to use and develop different experimental approaches in order to understand the prevalence and roles for mixed gap junction channels in human physiology.
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Affiliation(s)
- Michael Koval
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, GA, United States; Department of Cell Biology, Emory University, Atlanta, GA, United States.
| | - Samuel A Molina
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, GA, United States
| | - Janis M Burt
- Department of Physiology, University of Arizona, Tucson, AZ, United States
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Li T, Giaume C, Xiao L. Connexins-mediated glia networking impacts myelination and remyelination in the central nervous system. Mol Neurobiol 2014; 49:1460-71. [PMID: 24395132 DOI: 10.1007/s12035-013-8625-1] [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: 09/25/2013] [Accepted: 12/18/2013] [Indexed: 12/11/2022]
Abstract
In the central nervous system (CNS), the glial gap junctions are established among astrocytes (ASTs), oligodendrocytes (OLs), and/or between ASTs and OLs due to the expression of membrane proteins called connexins (Cxs). Together, the glial cells form a network of communicating cells that is important for the homeostasis of brain function for its involvement in the intercellular calcium wave propagation, exchange of metabolic substrates, cell proliferation, migration, and differentiation. Alternatively, Cxs are also involved in hemichannel function and thus participate in gliotransmission. In recent years, pathologic changes of oligodendroglia or demyelination found in transgenic mice with different subsets of Cxs or pharmacological insults suggest that glial Cxs may participate in the regulation of the myelination or remyelination processes. However, little is known about the underlying mechanisms. In this review, we will mainly focus on the functions of Cx-mediated gap junction channels, as well as hemichannels, in brain glial cells and discuss the way by which they impact myelination and remyelination. These aspects will be considered at the light of recent genetic and non-genetic studies related to demyelination and remyelination.
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Affiliation(s)
- Tao Li
- Department of Histology and Embryology, Faculty of Basic Medicine, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, No. 30 Gaotanyan Street, Chongqing, 400038, China,
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Levin MH, Bennett JL, Verkman AS. Optic neuritis in neuromyelitis optica. Prog Retin Eye Res 2013; 36:159-71. [PMID: 23545439 PMCID: PMC3770284 DOI: 10.1016/j.preteyeres.2013.03.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/13/2013] [Accepted: 03/18/2013] [Indexed: 12/31/2022]
Abstract
Neuromyelitis optica (NMO) is an autoimmune demyelinating disease associated with recurrent episodes of optic neuritis and transverse myelitis, often resulting in permanent blindness and/or paralysis. The discovery of autoantibodies (AQP4-IgG) that target aquaporin-4 (AQP4) has accelerated our understanding of the cellular mechanisms driving NMO pathogenesis. AQP4 is a bidirectional water channel expressed on the plasma membranes of astrocytes, retinal Müller cells, skeletal muscle, and some epithelial cells in kidney, lung and the gastrointestinal tract. AQP4 tetramers form regular supramolecular assemblies at the cell plasma membrane called orthogonal arrays of particles. The pathological features of NMO include perivascular deposition of immunoglobulin and activated complement, loss of astrocytic AQP4, inflammatory infiltration with granulocyte and macrophage accumulation, and demyelination with axon loss. Current evidence supports a causative role of AQP4-IgG in NMO, in which binding of AQP4-IgG to AQP4 orthogonal arrays on astrocytes initiates complement-dependent and antibody-dependent cell-mediated cytotoxicity and inflammation. Immunosuppression and plasma exchange are the mainstays of therapy for NMO optic neuritis. Novel therapeutics targeting specific steps in NMO pathogenesis are entering the development pipeline, including blockers of AQP4-IgG binding to AQP4 and inhibitors of granulocyte function. However, much work remains in understanding the unique susceptibility of the optic nerves in NMO, in developing animal models of NMO optic neuritis, and in improving therapies to preserve vision.
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Affiliation(s)
- Marc H Levin
- Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Cao J, Dwyer JB, Gautier NM, Leslie FM, Li MD. Central myelin gene expression during postnatal development in rats exposed to nicotine gestationally. Neurosci Lett 2013; 553:115-20. [PMID: 23962570 DOI: 10.1016/j.neulet.2013.08.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 08/06/2013] [Accepted: 08/07/2013] [Indexed: 01/29/2023]
Abstract
Abnormal myelin gene expression in the central nervous system (CNS) is associated with many mental illnesses, including psychiatric disorders and drug addiction. We have previously shown that prenatal exposure to nicotine, the major psychoactive component in cigarette smoke, alters myelin gene expression in the CNS of adolescent rats. To examine whether this effect is specific for adolescents, we examined myelin gene expression in the CNS of juveniles and adults. Pregnant Sprague-Dawley rats were treated with nicotine (3 mg/kg/day; GN) or saline (GS) via osmotic mini pumps from gestational days 4-18. Both male and female offspring were sacrificed at postnatal day P20-21 (juveniles), P35-36 (adolescents), or P59-60 (adults). Three limbic brain regions, the prefrontal cortex (PFC), caudate putamen (CPu), and nucleus accumbens (NAc), were dissected. The expression of genes encoding major myelin components was evaluated using quantitative RT-PCR. We found that GN altered myelin gene expression in juveniles with brain region and sex differences. The pattern of alteration was different from that observed in adolescents. Although these genes were expressed normally in male adults, we observed decreased expression in GN-treated female adults, especially in the CPu. Thus, GN altered myelin gene expression throughout postnatal development and adulthood. The effect on adolescents was quite different from that at other ages, which correlated with the unique symptoms of many psychiatric disorders during adolescence.
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Affiliation(s)
- Junran Cao
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia, Charlottesville, VA 22911, United States
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Escartin C, Rouach N. Astroglial networking contributes to neurometabolic coupling. FRONTIERS IN NEUROENERGETICS 2013; 5:4. [PMID: 23637659 PMCID: PMC3636502 DOI: 10.3389/fnene.2013.00004] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/18/2013] [Indexed: 12/21/2022]
Abstract
The strategic position of astrocytic processes between blood capillaries and neurons, provided the early insight that astrocytes play a key role in supplying energy substrates to neurons in an activity-dependent manner. The central role of astrocytes in neurometabolic coupling has been first established at the level of single cell. Since then, exciting recent work based on cellular imaging and electrophysiological recordings has provided new mechanistic insights into this phenomenon, revealing the crucial role of gap junction (GJ)-mediated networks of astrocytes. Indeed, astrocytes define the local availability of energy substrates by regulating blood flow. Subsequently, in order to efficiently reach distal neurons, these substrates can be taken up, and distributed through networks of astrocytes connected by GJs, a process modulated by neuronal activity. Astrocytic networks can be morphologically and/or functionally altered in the course of various pathological conditions, raising the intriguing possibility of a direct contribution from these networks to neuronal dysfunction. The present review upgrades the current view of neuroglial metabolic coupling, by including the recently unravelled properties of astroglial metabolic networks and their potential contribution to normal and pathological neuronal activity.
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Affiliation(s)
- Carole Escartin
- CEA DSV I2BM MIRCen and CNRS URA2210, Fontenay-aux-Roses Paris, France
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