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Talaverón R, Morado-Díaz CJ, Herrera A, Gálvez V, Pastor AM, Matarredona ER. The Gap Junction Inhibitor Octanol Decreases Proliferation and Increases Glial Differentiation of Postnatal Neural Progenitor Cells. Int J Mol Sci 2024; 25:6288. [PMID: 38927995 PMCID: PMC11203596 DOI: 10.3390/ijms25126288] [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: 03/30/2024] [Revised: 05/30/2024] [Accepted: 06/04/2024] [Indexed: 06/28/2024] Open
Abstract
Neural precursor cells (NPCs) that persist in the postnatal/adult subventricular zone (SVZ) express connexins that form hemichannels and gap junctions. Gap junctional communication plays a role in NPC proliferation and differentiation during development, but its relevance on postnatal age remains to be elucidated. In this work we aimed to evaluate the effect of the blockade of gap junctional communication on proliferation and cell fate of NPCs obtained from the SVZ of postnatal rats. NPCs were isolated and expanded in culture as neurospheres. Electron microscopy revealed the existence of gap junctions among neurosphere cells. Treatment of cultures with octanol, a broad-spectrum gap junction blocker, or with Gap27, a specific blocker for gap junctions formed by connexin43, produced a significant decrease in bromodeoxyuridine incorporation. Octanol treatment also exerted a dose-dependent antiproliferative effect on glioblastoma cells. To analyze possible actions on NPC fate, cells were seeded in the absence of mitogens. Treatment with octanol led to an increase in the percentage of astrocytes and oligodendrocyte precursors, whereas the percentage of neurons remained unchanged. Gap27 treatment, in contrast, did not modify the differentiation pattern of SVZ NPCs. Our results indicate that general blockade of gap junctions with octanol induces significant effects on the behavior of postnatal SVZ NPCs, by reducing proliferation and promoting glial differentiation.
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Affiliation(s)
- Rocío Talaverón
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, 41012 Seville, Spain;
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Camilo J. Morado-Díaz
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Alejandro Herrera
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Victoria Gálvez
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Angel M. Pastor
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Esperanza R. Matarredona
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
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Chu H, Dong J, Tang Y, Huang C, Guo Q. Connexin 43 Promotes Neurogenesis via Regulating Aquaporin-4 after Cerebral Ischemia. Neurotox Res 2023; 41:349-361. [PMID: 37074591 DOI: 10.1007/s12640-023-00646-3] [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: 01/25/2023] [Revised: 03/27/2023] [Accepted: 04/02/2023] [Indexed: 04/20/2023]
Abstract
We aimed to test the effects of connexin43 (Cx43) on ischemic neurogenesis and examined whether it was dependent on aquaporin-4 (AQP4). We detected the expression of Cx43 and AQP4 in the ipsilateral subventricular zone (SVZ) and peri-infarct cortex after middle cerebral artery occlusion (MCAO). Also, we examined neurogenesis in the above regions via co-labeling of 5-bromo-2-deoxyuridine (BrdU)/neuronal nuclear antigen (NeuN) and BrdU/doublecortin (DCX). The effects of Cx43 and AQP4 were investigated by using two transgenic animals: heterozygous Cx43 (Cx43±) mice and AQP4 knockout (AQP4-/-) mice, and connexin mimetic peptide (CMP), a selective Cx43 blocker. We demonstrated AQP4 and Cx43 were co-expressed in the astrocytes after MCAO and the expression was highly increased in ipsilateral SVZ and peri-infarct cortex. Cx43± mice had larger infarction volumes and worse neurological function. Both BrdU/NeuN and BrdU/DCX co-labeled cells in the two regions were reduced in Cx43± and AQP4-/- mice compared to wild-type (WT) mice, suggesting Cx43 and AQP4 participated in neurogenesis of neural stem cells. Moreover, CMP decreased AQP4 expression and inhibited neurogenesis in WT mice, while the latter failed to be observed in AQP4-/- mice. Besides, higher levels of IL-1β and TNF-α were detected in the SVZ and peri-infarct cortex of AQP4-/- and Cx43± mice than those in WT mice. In conclusion, our data suggest that Cx43 elicits neuroprotective effects after cerebral ischemia through promoting neurogenesis in the SVZ to regenerate the injured neurons, which is AQP4 dependent and associated with down-regulation of inflammatory cytokines IL-1β and TNF-α.
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Affiliation(s)
- Heling Chu
- Department of Gerontology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, No. 600 Yishan Road, 200233, Shanghai, China
| | - Jing Dong
- Department of Internal Neurology, Qingdao Municipal Hospital, Qingdao, China
| | - Yuping Tang
- Department of Neurology, Huashan Hospital, Fudan University, No. 12 Mid. Wulumuqi Road, Shanghai, 200040, China.
| | - Chuyi Huang
- Health Management Center, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, No. 160 Pujian Road, Shanghai, 200120, China.
| | - Qihao Guo
- Department of Gerontology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, No. 600 Yishan Road, 200233, Shanghai, China.
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3
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Genet N, Genet G, Chavkin NW, Paila U, Fang JS, Vasavada HH, Goldberg JS, Acharya BR, Bhatt NS, Baker K, McDonnell SP, Huba M, Sankaranarayanan D, Ma GZM, Eichmann A, Thomas JL, Ffrench-Constant C, Hirschi KK. Connexin 43-mediated neurovascular interactions regulate neurogenesis in the adult brain subventricular zone. Cell Rep 2023; 42:112371. [PMID: 37043357 PMCID: PMC10564973 DOI: 10.1016/j.celrep.2023.112371] [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: 04/12/2022] [Revised: 02/20/2023] [Accepted: 03/22/2023] [Indexed: 04/13/2023] Open
Abstract
The subventricular zone (SVZ) is the largest neural stem cell (NSC) niche in the adult brain; herein, the blood-brain barrier is leaky, allowing direct interactions between NSCs and endothelial cells (ECs). Mechanisms by which direct NSC-EC interactions in the adult SVZ control NSC behavior are unclear. We found that Cx43 is highly expressed by SVZ NSCs and ECs, and its deletion in either leads to increased NSC proliferation and neuroblast generation, suggesting that Cx43-mediated NSC-EC interactions maintain NSC quiescence. This is further supported by single-cell RNA sequencing and in vitro studies showing that ECs control NSC proliferation by regulating expression of genes associated with NSC quiescence and/or activation in a Cx43-dependent manner. Cx43 mediates these effects in a channel-independent manner involving its cytoplasmic tail and ERK activation. Such insights inform adult NSC regulation and maintenance aimed at stem cell therapies for neurodegenerative disorders.
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Affiliation(s)
- Nafiisha Genet
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA.
| | - Gael Genet
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Nicholas W Chavkin
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Umadevi Paila
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Jennifer S Fang
- Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Hema H Vasavada
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Joshua S Goldberg
- Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Bipul R Acharya
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Neha S Bhatt
- Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Kasey Baker
- Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06511, USA; Departments of Neuroscience and Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Stephanie P McDonnell
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Mahalia Huba
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Danya Sankaranarayanan
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Gerry Z M Ma
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK; Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, UK
| | - Anne Eichmann
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Jean-Leon Thomas
- Departments of Neuroscience and Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Charles Ffrench-Constant
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK; Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, UK
| | - Karen K Hirschi
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA.
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Wang Y, Xiang L, Wang F, Redmile-Gordon M, Bian Y, Wang Z, Gu C, Jiang X, Schäffer A, Xing B. Transcriptomic and metabolomic changes in lettuce triggered by microplastics-stress. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 320:121081. [PMID: 36646407 DOI: 10.1016/j.envpol.2023.121081] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Microplastics (MPs) are a global threat to the environment, and plant uptake of MP particles (≤0.2 μm) is a particular cause for concern. However, physiological and molecular mechanisms underlying MP-induced growth inhibition need to be clarified. Towards this goal, we conducted a hydroponic experiment to investigate the accumulation of MPs, changes in physiology, gene expression, and metabolites in lettuce from a series of concentrations of fluorescence-labelled polystyrene MPs (0, 10, 20, 30, 40, 50 mg L-1, ∼0.2 μm). Our results showed that MPs accumulated in the lettuce root tips and leaf veins, resulting in the hypertonic injury of lettuce, and the down-regulation of genes related to ion homeostasis. Stress-related genes were up-regulated, and sphingolipid metabolism increased in response to MP additions, causing increased biosynthesis of ascorbic acid, terpenoid, and flavonoids in root exudates. Our findings provide a molecular-scale perspective on the response of leafy vegetables to MP-stress at a range of concentrations. This enables more comprehensive evaluation of the risks of MPs to human health and the ecological environment.
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Affiliation(s)
- Yu Wang
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China
| | - Leilei Xiang
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China
| | - Fang Wang
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China; Institute for Environmental Research, RWTH Aachen University, Aachen 52074, Germany.
| | - Marc Redmile-Gordon
- Department of Environmental Horticulture, Royal Horticultural Society, Wisley, Surrey, GU23 6QB, UK
| | - Yongrong Bian
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China
| | - Ziquan Wang
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China
| | - Chenggang Gu
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China
| | - Xin Jiang
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008, China; University of Chinese Academy of Science, Beijing 100049, China
| | - Andreas Schäffer
- Institute for Environmental Research, RWTH Aachen University, Aachen 52074, Germany
| | - Baoshan Xing
- Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA
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5
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Baracaldo-Santamaría D, Corrales-Hernández MG, Ortiz-Vergara MC, Cormane-Alfaro V, Luque-Bernal RM, Calderon-Ospina CA, Cediel-Becerra JF. Connexins and Pannexins: Important Players in Neurodevelopment, Neurological Diseases, and Potential Therapeutics. Biomedicines 2022; 10:2237. [PMID: 36140338 PMCID: PMC9496069 DOI: 10.3390/biomedicines10092237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
Cell-to-cell communication is essential for proper embryonic development and its dysfunction may lead to disease. Recent research has drawn attention to a new group of molecules called connexins (Cxs) and pannexins (Panxs). Cxs have been described for more than forty years as pivotal regulators of embryogenesis; however, the exact mechanism by which they provide this regulation has not been clearly elucidated. Consequently, Cxs and Panxs have been linked to congenital neurodegenerative diseases such as Charcot-Marie-Tooth disease and, more recently, chronic hemichannel opening has been associated with adult neurodegenerative diseases (e.g., Alzheimer's disease). Cell-to-cell communication via gap junctions formed by hexameric assemblies of Cxs, known as connexons, is believed to be a crucial component in developmental regulation. As for Panxs, despite being topologically similar to Cxs, they predominantly seem to form channels connecting the cytoplasm to the extracellular space and, despite recent research into Panx1 (Pannexin 1) expression in different regions of the brain during the embryonic phase, it has been studied to a lesser degree. When it comes to the nervous system, Cxs and Panxs play an important role in early stages of neuronal development with a wide span of action ranging from cellular migration during early stages to neuronal differentiation and system circuitry formation. In this review, we describe the most recent available evidence regarding the molecular and structural aspects of Cx and Panx channels, their role in neurodevelopment, congenital and adult neurological diseases, and finally propose how pharmacological modulation of these channels could modify the pathogenesis of some diseases.
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Affiliation(s)
- Daniela Baracaldo-Santamaría
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - María Gabriela Corrales-Hernández
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Maria Camila Ortiz-Vergara
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Valeria Cormane-Alfaro
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Ricardo-Miguel Luque-Bernal
- Anatomy and Embriology Units, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Carlos-Alberto Calderon-Ospina
- Pharmacology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
- GENIUROS Research Group, Center for Research in Genetics and Genomics (CIGGUR), School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
| | - Juan-Fernando Cediel-Becerra
- Histology and Embryology Unit, Department of Biomedical Sciences, School of Medicine and Health Sciences, Universidad del Rosario, Bogotá 111221, Colombia
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Podgorny OV, Gulyaeva NV. Glucocorticoid-mediated mechanisms of hippocampal damage: Contribution of subgranular neurogenesis. J Neurochem 2020; 157:370-392. [PMID: 33301616 DOI: 10.1111/jnc.15265] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/09/2020] [Accepted: 11/30/2020] [Indexed: 12/19/2022]
Abstract
A comprehensive overview of the interplay between glucocorticoids (GCs) and adult hippocampal neurogenesis (AHN) is presented, particularly, in the context of a diseased brain. The effectors of GCs in the dentate gyrus neurogenic niche of the hippocampal are reviewed, and the consequences of the GC signaling on the generation and integration of new neurons are discussed. Recent findings demonstrating how GC signaling mediates impairments of the AHN in various brain pathologies are overviewed. GC-mediated effects on the generation and integration of adult-born neurons in the hippocampal dentate gyrus depend on the nature, severity, and duration of the acting stress factor. GCs realize their effects on the AHN primarily via specific glucocorticoid and mineralocorticoid receptors. Disruption of the reciprocal regulation between the hypothalamic-pituitary-adrenal (HPA) axis and the generation of the adult-born granular neurons is currently considered to be a key mechanism implicating the AHN into the pathogenesis of numerous brain diseases, including those without a direct hippocampal damage. These alterations vary from reduced proliferation of stem and progenitor cells to increased cell death and abnormalities in morphology, connectivity, and localization of young neurons. Although the involvement of the mutual regulation between the HPA axis and the AHN in the pathogenesis of cognitive deficits and mood impairments is evident, several unresolved critical issues are stated. Understanding the details of GC-mediated mechanisms involved in the alterations in AHN could enable the identification of molecular targets for ameliorating pathology-induced imbalance in the HPA axis/AHN mutual regulation to conquer cognitive and psychiatric disturbances.
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Affiliation(s)
- Oleg V Podgorny
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, Russia.,Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia
| | - Natalia V Gulyaeva
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.,Research and Clinical Center for Neuropsychiatry of Moscow Healthcare Department, Moscow, Russia
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7
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Portal B, Guiard BP. [Role of astrocytic connexins in the regulation of extracellular glutamate levels: implication for the treatment of major depressive episodes]. Biol Aujourdhui 2020; 214:71-83. [PMID: 33357364 DOI: 10.1051/jbio/2020008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Indexed: 11/14/2022]
Abstract
Major depression is a psychiatric disorder relying on different neurobiological mechanisms. In particular, a hypersensitivity of the hypothalamic-pituitary-adrenal axis leading to an excess of cortisol in blood and a deficit in monoaminergic neurotransmission have been associated with mood disorders. In keeping with these mechanisms, currently available antidepressant drugs act by increasing the extracellular levels of monoamines in the synaptic cleft. Since the discovery of the rapid and long-lasting antidepressant effects of ketamine, an NMDA receptor antagonist, a growing attention in psychiatry is paid to the pharmacological tools able to attenuate glutamatergic neurotransmission. Astrocytes play an important role in the excitatory/inhibitory balance of the central nervous system through the regulation of glutamate reuptake and secretion. Interestingly, the release of this excitatory amino acid is controlled, at least in part, by plasma membrane proteins (i.e. connexins) that cluster together to form gap junctions or hemichannels. Preclinical evidence suggests that these functional entities play a critical role in emotional behaviour. After a brief overview of the literature on mood disorders and related treatments, this review describes the role of astrocytes and connexins in glutamatergic neurotransmission and major depression. Moreover, we highlight the arguments supporting the therapeutic potential of connexins blockers but also the practical difficulties to target the hemichannels while maintaining gap junctions intact.
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Affiliation(s)
- Benjamin Portal
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, 31000 Toulouse, France
| | - Bruno P Guiard
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, 31000 Toulouse, France
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Araki T, Ikegaya Y, Koyama R. The effects of microglia‐ and astrocyte‐derived factors on neurogenesis in health and disease. Eur J Neurosci 2020; 54:5880-5901. [PMID: 32920880 PMCID: PMC8451940 DOI: 10.1111/ejn.14969] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/20/2022]
Abstract
Hippocampal neurogenesis continues throughout life and has been suggested to play an essential role in maintaining spatial cognitive function under physiological conditions. An increasing amount of evidence has indicated that adult neurogenesis is tightly controlled by environmental conditions in the neurogenic niche, which consists of multiple types of cells including microglia and astrocytes. Microglia maintain the environment of neurogenic niche through their phagocytic capacity and interaction with neurons via fractalkine‐CX3CR1 signaling. In addition, microglia release growth factors such as brain‐derived neurotrophic factor (BDNF) and cytokines such as tumor necrosis factor (TNF)‐α to support the development of adult born neurons. Astrocytes also manipulate neurogenesis by releasing various soluble factors including adenosine triphosphate and lactate. Whereas, under pathological conditions such as Alzheimer's disease, depression, and epilepsy, microglia and astrocytes play a leading role in inflammation and are involved in attenuating the normal process of neurogenesis. The modulation of glial functions on neurogenesis in these brain diseases are attracting attention as a new therapeutic target. This review describes how these glial cells play a role in adult hippocampal neurogenesis in both health and disease, especially focusing glia‐derived factors.
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Affiliation(s)
- Tasuku Araki
- Laboratory of Chemical Pharmacology Graduate School of Pharmaceutical Sciences The University of Tokyo Tokyo Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology Graduate School of Pharmaceutical Sciences The University of Tokyo Tokyo Japan
- Center for Information and Neural Networks Suita City Osaka Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology Graduate School of Pharmaceutical Sciences The University of Tokyo Tokyo Japan
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9
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Deshpande T, Li T, Henning L, Wu Z, Müller J, Seifert G, Steinhäuser C, Bedner P. Constitutive deletion of astrocytic connexins aggravates kainate-induced epilepsy. Glia 2020; 68:2136-2147. [PMID: 32240558 DOI: 10.1002/glia.23832] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/17/2020] [Accepted: 03/17/2020] [Indexed: 01/08/2023]
Abstract
The astroglial gap junctional network formed by connexin (Cx) channels plays a central role in regulating neuronal activity and network synchronization. However, its involvement in the development and progression of epilepsy is not yet understood. Loss of interastrocytic gap junction (GJ) coupling has been observed in the sclerotic hippocampus of patients with mesial temporal lobe epilepsy (MTLE) and in mouse models of MTLE, leading to the suggestion that it plays a causative role in the pathogenesis. To further elucidate this clinically relevant question, we investigated consequences of astrocyte disconnection on the time course and severity of kainate-induced MTLE with hippocampal sclerosis (HS) by comparing mice deficient for astrocytic Cx proteins with wild-type mice (WT). Continuous telemetric EEG recordings and video monitoring performed over a period of 4 weeks after epilepsy induction revealed substantially higher seizure and interictal spike activity during the chronic phase in Cx deficient versus WT mice, while the severity of status epilepticus was not different. Immunohistochemical analysis showed that, despite the elevated chronic seizure activity, astrocyte disconnection did not aggravate the severity of HS. Indeed, the extent of CA1 pyramidal cell loss was similar between the experimental groups, while astrogliosis, granule cell dispersion, angiogenesis, and microglia activation were even reduced in Cx deficient as compared to WT mice. Interestingly, seizure-induced neurogenesis in the adult dentate gyrus was also independent of astrocytic Cxs. Together, our data indicate that constitutive loss of GJ coupling between astrocytes promotes neuronal hyperexcitability and attenuates seizure-induced histopathological outcomes.
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Affiliation(s)
- Tushar Deshpande
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Tingsong Li
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Lukas Henning
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Zhou Wu
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Julia Müller
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Gerald Seifert
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Peter Bedner
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
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10
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Uncoupling of the Astrocyte Syncytium Differentially Affects AQP4 Isoforms. Cells 2020; 9:cells9020382. [PMID: 32046059 PMCID: PMC7072498 DOI: 10.3390/cells9020382] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/29/2020] [Accepted: 02/04/2020] [Indexed: 11/25/2022] Open
Abstract
The water channel protein aquaporin-4 (AQP4) and the gap junction forming proteins connexin-43 (Cx43) and connexin-30 (Cx30) are astrocytic proteins critically involved in brain water and ion homeostasis. While AQP4 is mainly involved in water flux across the astrocytic endfeet membranes, astrocytic gap junctions provide syncytial coupling allowing intercellular exchange of water, ions, and other molecules. We have previously shown that mice with targeted deletion of Aqp4 display enhanced gap junctional coupling between astrocytes. Here, we investigate whether uncoupling of the astrocytic syncytium by deletion of the astrocytic connexins Cx43 and Cx30 affects AQP4 membrane localization and expression. By using quantitative immunogold cytochemistry, we show that deletion of astrocytic connexins leads to a substantial reduction of perivascular AQP4, concomitant with a down-regulation of total AQP4 protein and mRNA. Isoform expression analysis shows that while the level of the predominant AQP4 M23 isoform is reduced in Cx43/Cx30 double deficient hippocampal astrocytes, the levels of M1, and the alternative translation AQP4ex isoform protein levels are increased. These findings reveal a complex interdependence between AQP4 and connexins, which are both significantly involved in homeostatic functions and astrogliopathologies.
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Astrocytes in multiple sclerosis and experimental autoimmune encephalomyelitis: Star-shaped cells illuminating the darkness of CNS autoimmunity. Brain Behav Immun 2019; 80:10-24. [PMID: 31125711 DOI: 10.1016/j.bbi.2019.05.029] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 05/16/2019] [Accepted: 05/20/2019] [Indexed: 12/18/2022] Open
Abstract
Neuropathology in the human autoimmune disease multiple sclerosis (MS) is considered to be mediated by autoreactive leukocytes, such as T cells, B cells, and macrophages. However, the inflammation and tissue damage in MS and its animal model experimental autoimmune encephalomyelitis (EAE) is also critically regulated by astrocytes, the most abundant cell population in the central nervous system (CNS). Under physiological conditions, astrocytes are integral to the development and function of the CNS, whereas in CNS autoimmunity, astrocytes influence the pathogenesis, progression, and recovery of the diseases. In this review, we summarize recent advances in astrocytic functions in the context of MS and EAE, which are categorized into two opposite aspects, one being detrimental and the other beneficial. Inhibition of the detrimental functions and/or enhancement of the beneficial functions of astrocytes might be favorable for the treatment of MS.
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Ali AAH, Stahr A, Ingenwerth M, Theis M, Steinhäuser C, von Gall C. Connexin30 and Connexin43 show a time-of-day dependent expression in the mouse suprachiasmatic nucleus and modulate rhythmic locomotor activity in the context of chronodisruption. Cell Commun Signal 2019; 17:61. [PMID: 31186021 PMCID: PMC6560876 DOI: 10.1186/s12964-019-0370-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/14/2019] [Indexed: 11/15/2022] Open
Abstract
Background The astroglial connexins Cx30 and Cx43 contribute to many important CNS functions including cognitive behaviour, motoric capacity and regulation of the sleep-wake cycle. The sleep wake cycle, is controlled by the circadian system. The central circadian rhythm generator resides in the suprachiasmatic nucleus (SCN). SCN neurons are tightly coupled in order to generate a coherent circadian rhythm. The SCN receives excitatory glutamatergic input from the retina which mediates entrainment of the circadian system to the environmental light-dark cycle. Connexins play an important role in electric coupling of SCN neurons and astrocytic-neuronal signalling that regulates rhythmic SCN neuronal activity. However, little is known about the regulation of Cx30 and Cx43 expression in the SCN, and the role of these connexins in light entrainment of the circadian system and in circadian rhythm generation. Methods We analysed time-of-day dependent as well as circadian expression of Cx30 and Cx43 mRNA and protein in the mouse SCN by means of qPCR and immunohistochemistry. Moreover, we analysed rhythmic spontaneous locomotor activity in mice with a targeted deletion of Cx30 and astrocyte specific deletion of Cx43 (DKO) in different light regimes by means of on-cage infrared detectors. Results Fluctuation of Cx30 protein expression is strongly dependent on the light-dark cycle whereas fluctuation of Cx43 protein expression persisted in constant darkness. DKO mice entrained to the light-dark cycle. However, re-entrainment after a phase delay was slightly impaired in DKO mice. Surprisingly, DKO mice were more resilient to chronodisruption. Conclusion Circadian fluctuation of Cx30 and Cx43 protein expression in the SCN is differently regulated. Cx30 and astroglial Cx43 play a role in rhythm stability and re-entrainment under challenging conditions. Electronic supplementary material The online version of this article (10.1186/s12964-019-0370-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Amira A H Ali
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Merowinger Platz 1A, 40225, Düsseldorf, Germany
| | - Anna Stahr
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Merowinger Platz 1A, 40225, Düsseldorf, Germany
| | - Marc Ingenwerth
- Institute of Pathology, Medical Faculty, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany
| | - Martin Theis
- Institute of Cellular Neurosciences, Medical Faculty, University Bonn, Sigmund Freud Str. 25, 53105, Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University Bonn, Sigmund Freud Str. 25, 53105, Bonn, Germany
| | - Charlotte von Gall
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Merowinger Platz 1A, 40225, Düsseldorf, Germany.
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