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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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Gilloteaux J, De Swert K, Suain V, Brion JP, Nicaise C. Loss of Ephaptic Contacts in the Murine Thalamus during Osmotic Demyelination Syndrome. Ultrastruct Pathol 2023; 47:398-423. [PMID: 37477534 DOI: 10.1080/01913123.2023.2232452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/10/2023] [Accepted: 06/29/2023] [Indexed: 07/22/2023]
Abstract
BACKGROUND AND AIM A murine model mimicking osmotic demyelination syndrome (ODS) revealed with histology in the relay posterolateral (VPL) and ventral posteromedial (VPM) thalamic nuclei adjoined nerve cell bodies in chronic hyponatremia, amongst the damaged 12 h and 48 h after reinstatement of osmolality. This report aims to verify and complement with ultrastructure other neurophysiology, immunohistochemistry, and molecular biochemistry data to assess the connexin-36 protein, as part of those hinted close contacts.This ODS investigation included four groups of mice: Sham (NN; n = 13), hyponatremic (HN; n = 11), those sacrificed 12 h after a fast restoration of normal natremia (ODS12h; n = 6) and mice sacrificed 48 h afterward, or ODS48 h (n = 9). Out of these, thalamic zones samples included NN (n = 2), HN (n = 2), ODS12h (n = 3) and ODS48h (n = 3). RESULTS Ultrastructure illustrated junctions between nerve cell bodies that were immunolabeled with connexin36 (Cx36) with light microscopy and Western blots. These cell's junctions were reminiscent of low resistance junctions characterized in other regions of the CNS with electrophysiology. Contiguous neurons showed neurolemma contacts in intact and damaged tissues according to their location in the ODS zones, at 12 h and 48 h post correction along with other demyelinating alterations. Neurons and ephaptic contact measurements indicated the highest alterations, including nerve cell necrosis in the ODS epicenter and damages decreased toward the outskirts of the demyelinated zone. CONCLUSION Ephapses contained C × 36between intact or ODS injured neurons in the thalamus appeared to be resilient beyond the core degraded tissue injuries. These could maintain intercellular ionic and metabolite exchanges between these lesser injured regions and, thus, would partake to some brain plasticity repairs.
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Affiliation(s)
- Jacques Gilloteaux
- Department of Medicine, URPHyM, NARILIS, Université de Namur, Namur, Belgium
- Department of Anatomical Sciences, St George's University School of Medicine, Newcastle Upon Tyne, UK
| | - Kathleen De Swert
- Department of Medicine, URPHyM, NARILIS, Université de Namur, Namur, Belgium
| | - Valérie Suain
- Laboratory of Histology, Neuroanatomy and Neuropathology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Jean-Pierre Brion
- Laboratory of Histology, Neuroanatomy and Neuropathology, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Charles Nicaise
- Department of Medicine, URPHyM, NARILIS, Université de Namur, Namur, Belgium
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Brown-Panton CA, Sabour S, Zoidl GSO, Zoidl C, Tabatabaei N, Zoidl GR. Gap junction Delta-2b ( gjd2b/Cx35.1) depletion causes hyperopia and visual-motor deficiencies in the zebrafish. Front Cell Dev Biol 2023; 11:1150273. [PMID: 36936688 PMCID: PMC10017553 DOI: 10.3389/fcell.2023.1150273] [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: 01/23/2023] [Accepted: 02/15/2023] [Indexed: 03/06/2023] Open
Abstract
The zebrafish is a powerful model to investigate the developmental roles of electrical synapses because many signaling pathways that regulate the development of the nervous system are highly conserved from fish to humans. Here, we provide evidence linking the mammalian connexin-36 (Cx36) ortholog gjd2b/Cx35.1, a major component of electrical synapses in the zebrafish, with a refractive error in the context of morphological, molecular, and behavioral changes of zebrafish larvae. Two abnormalities were identified. The optical coherence tomography analysis of the adult retina confirmed changes to the refractive properties caused by eye axial length reduction, leading to hyperopic shifts. The gjd2b/Cx35.1 depletion was also correlated with morphological changes to the head and body ratios in larvae. The differential expression of Wnt/ß-catenin signaling genes, connexins, and dopamine receptors suggested a contribution to the observed phenotypic differences. The alteration of visual-motor behavioral responses to abrupt light transitions was aggravated in larvae, providing evidence that cone photoreceptor cell activity was enhanced when gjd2b/Cx35.1 was depleted. The visual disturbances were reversed under low light conditions in gjd2b -/- /Cx35.1-/- larvae. Since qRT-PCR data demonstrated that two rhodopsin genes were downregulated, we speculated that rod photoreceptor cells in gjd2b/Cx35.1-/- larvae were less sensitive to bright light transitions, thus providing additional evidence that a cone-mediated process caused the VMR light-ON hyperactivity after losing Cx35.1 expression. Together, this study provides evidence for the role of gjd2b/Cx35.1 in the development of the visual system and visually guided behaviors.
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Affiliation(s)
- Cherie A. Brown-Panton
- Department of Biology, York University, Toronto, ON, Canada
- Center for Vision Research, York University, Toronto, ON, Canada
- *Correspondence: Cherie A. Brown-Panton, ; Georg R. Zoidl,
| | - Shiva Sabour
- Department of Mechanical Engineering, York University, Toronto, ON, Canada
| | - Georg S. O. Zoidl
- Department of Biology, York University, Toronto, ON, Canada
- Center for Vision Research, York University, Toronto, ON, Canada
| | - Christiane Zoidl
- Department of Biology, York University, Toronto, ON, Canada
- Center for Vision Research, York University, Toronto, ON, Canada
| | - Nima Tabatabaei
- Center for Vision Research, York University, Toronto, ON, Canada
- Department of Mechanical Engineering, York University, Toronto, ON, Canada
| | - Georg R. Zoidl
- Department of Biology, York University, Toronto, ON, Canada
- Center for Vision Research, York University, Toronto, ON, Canada
- Department of Psychology, York University, Toronto, ON, Canada
- *Correspondence: Cherie A. Brown-Panton, ; Georg R. Zoidl,
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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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Fang K, Chen S, Wang Y, Chen F, Cui M, Dong Q. Asymmetric Dimethylarginine Protects Neurons from Oxygen Glucose Deprivation Insult by Modulating Connexin-36 Expression. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5339361. [PMID: 35847590 PMCID: PMC9279069 DOI: 10.1155/2022/5339361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 05/30/2022] [Accepted: 06/06/2022] [Indexed: 11/18/2022]
Abstract
Background Asymmetric dimethylarginine (ADMA) is a nonselective nitric oxide synthase inhibitor. ADMA is thought to inhibit the production of nitric oxide (NO) by neurons after oxygen-glucose deprivation (OGD). The gap junction protein Connexin-36 (cx-36) is involved in the pathophysiology of stroke. We investigated whether ADMA could protect neurons from OGD insults by regulating the expression of cx-36. Methods Cultured rat cortical neuronal cells were used. Neurons were treated with OGD with or without ADMA pretreatment. The lactate dehydrogenase (LDH) release rate was used to assess neuronal injury. Intracellular NO levels were determined using 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate. Western blotting was performed to detect cx-36 expression. Results The LDH release rate increased in the supernatant of neurons after the OGD insult, whereas ADMA treatment reduced the LDH release rate. Intracellular NO levels increased following OGD treatment, and this increase was not inhibited by ADMA treatment. Expression of cx-36 was upregulated in neurons under OGD conditions, and treatment with ADMA downregulated the expression of cx-36. Conclusions ADMA protects neurons from OGD insult, and cx-36 downregulation may be a possible pathway involved in ADMA-mediated neuronal protection.
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Affiliation(s)
- Kun Fang
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Shufen Chen
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Yi Wang
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Fangzhe Chen
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Mei Cui
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Qiang Dong
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
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Köse B, Özkan M, Sur-Erdem İ, Çavdar S. Does astrocyte gap junction protein expression level differ during development in the absence epileptic rats? Synapse 2022; 76:e22225. [PMID: 35137459 DOI: 10.1002/syn.22225] [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: 11/17/2021] [Revised: 01/05/2022] [Accepted: 01/27/2022] [Indexed: 11/09/2022]
Abstract
Intercellular communication via gap junctions (GJ) has a wide variety of complex and essential functions in the CNS. In the present developmental study, we aimed to quantify the number of astrocytic GJ protein connexin 30 (Cx30) of genetic absence epilepsy rats from Strasbourg (GAERS) at postnatal P10, P30, and P60 days in the epileptic focal areas involved in the cortico-thalamic circuit. We compared the results with Wistar rats using immunohistochemistry and Western Blotting. The number of Cx30 immunopositive astrocytes in per unit area were quantified for the somatosensory cortex (SSCx), ventrobasal (VB), and lateral geniculate (LGN) of the two strains and Cx30 Western Blot was applied to the tissue samples from the same regions. Both immunohistochemical and Western Blot results revealed the presence of Cx30 in all regions studied at P10 in both Wistar and GAERS animals. The SSCx, VB, and LGN of Wistar animals showed progressive increase in the number of Cx30 immunopositive labelled astrocytes from P10 to P30 and reached a peak at P30; then a significant decline was observed from P30 to P60 for the SSCx and VB. However, in GAERS Cx30 immunopositive labelled astrocytes showed a progressive increase from P10 to P60 for all brain regions studied. The immunohistochemical data highly corresponded with Western Blotting results. We conclude that the developmental disproportional expression of Cx30 in the epileptic focal areas in GAERS may be related to the onset of absence seizures or may be related to the neurogenesis of absence epilepsy. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Büşra Köse
- Department of Anatomy, Koç University School of Medicine, Istanbul, Turkey
| | - Mazhar Özkan
- Department of Anatomy, Tekirdağ Namık Kemal University School of Medicine, Istanbul, Turkey
| | - İlknur Sur-Erdem
- Department of Molecular Biology, Koç University School of Medicine, Istanbul, Turkey
| | - Safiye Çavdar
- Department of Anatomy, Koç University School of Medicine, Istanbul, Turkey
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Talukdar S, Emdad L, Das SK, Fisher PB. GAP junctions: multifaceted regulators of neuronal differentiation. Tissue Barriers 2021; 10:1982349. [PMID: 34651545 DOI: 10.1080/21688370.2021.1982349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Gap junctions are intercellular membrane channels consisting of connexin proteins, which contribute to direct cytoplasmic exchange of small molecules, substrates and metabolites between adjacent cells. These channels play important roles in neuronal differentiation, maintenance, survival and function. Gap junctions regulate differentiation of neurons from embryonic, neural and induced pluripotent stem cells. In addition, they control transdifferentiation of neurons from mesenchymal stem cells. The expression and levels of several connexins correlate with cell cycle changes and different stages of neurogenesis. Connexins such as Cx36, Cx45, and Cx26, play a crucial role in neuronal function. Several connexin knockout mice display lethal or severely impaired phenotypes. Aberrations in connexin expression is frequently associated with various neurodegenerative disorders. Gap junctions also act as promising therapeutic targets for neuronal regenerative medicine, because of their role in neural stem cell integration, injury and remyelination.
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Affiliation(s)
- Sarmistha Talukdar
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States
| | - Luni Emdad
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States.,Vcu Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Swadesh K Das
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States.,Vcu Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States.,Vcu Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
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Panda AK, K R, Gebrekrstos A, Bose S, Markandeya YS, Mehta B, Basu B. Tunable Substrate Functionalities Direct Stem Cell Fate toward Electrophysiologically Distinguishable Neuron-like and Glial-like Cells. ACS APPLIED MATERIALS & INTERFACES 2021; 13:164-185. [PMID: 33356098 DOI: 10.1021/acsami.0c17257] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Engineering cellular microenvironment on a functional platform using various biophysical cues to modulate stem cell fate has been the central theme in regenerative engineering. Among the various biophysical cues to direct stem cell differentiation, the critical role of physiologically relevant electric field (EF) stimulation was established in the recent past. The present study is the first to report the strategy to switch EF-mediated differentiation of human mesenchymal stem cells (hMSCs) between neuronal and glial pathways, using tailored functional properties of the biomaterial substrate. We have examined the combinatorial effect of substrate functionalities (conductivity, electroactivity, and topography) on the EF-mediated stem cell differentiation on polyvinylidene-difluoride (PVDF) nanocomposites in vitro, without any biochemical inducers. The functionalities of PVDF have been tailored using conducting nanofiller (multiwall-carbon nanotube, MWNT) and piezoceramic (BaTiO3, BT) by an optimized processing approach (melt mixing-compression molding-rolling). The DC conductivity of PVDF nanocomposites was tuned from ∼10-11 to ∼10-4 S/cm and the dielectric constant from ∼10 to ∼300. The phenotypical changes and genotypical expression of hMSCs revealed the signatures of early differentiation toward neuronal pathway on rolled-PVDF/MWNT and late differentiation toward glial lineage on rolled-PVDF/BT/MWNT. Moreover, we were able to distinguish the physiological properties of differentiated neuron-like and glial-like cells using membrane depolarization and mechanical stimulation. The excitability of the EF-stimulated hMSCs was also determined using whole-cell patch-clamp recordings. Mechanistically, the roles of intracellular reactive oxygen species (ROS), Ca2+ oscillations, and synaptic and gap junction proteins in directing the cellular fate have been established. Therefore, the present work critically unveils complex yet synergistic interaction of substrate functional properties to direct EF-mediated differentiation toward neuron-like and glial-like cells, with distinguishable electrophysiological responses.
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Affiliation(s)
- Asish Kumar Panda
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Ravikumar K
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Amanuel Gebrekrstos
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Suryasarathi Bose
- Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Yogananda S Markandeya
- Department of Biophysics, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Bhupesh Mehta
- Department of Biophysics, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Bikramjit Basu
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
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Mesnil M, Defamie N, Naus C, Sarrouilhe D. Brain Disorders and Chemical Pollutants: A Gap Junction Link? Biomolecules 2020; 11:51. [PMID: 33396565 PMCID: PMC7824109 DOI: 10.3390/biom11010051] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The incidence of brain pathologies has increased during last decades. Better diagnosis (autism spectrum disorders) and longer life expectancy (Parkinson's disease, Alzheimer's disease) partly explain this increase, while emerging data suggest pollutant exposures as a possible but still underestimated cause of major brain disorders. Taking into account that the brain parenchyma is rich in gap junctions and that most pollutants inhibit their function; brain disorders might be the consequence of gap-junctional alterations due to long-term exposures to pollutants. In this article, this hypothesis is addressed through three complementary aspects: (1) the gap-junctional organization and connexin expression in brain parenchyma and their function; (2) the effect of major pollutants (pesticides, bisphenol A, phthalates, heavy metals, airborne particles, etc.) on gap-junctional and connexin functions; (3) a description of the major brain disorders categorized as neurodevelopmental (autism spectrum disorders, attention deficit hyperactivity disorders, epilepsy), neurobehavioral (migraines, major depressive disorders), neurodegenerative (Parkinson's and Alzheimer's diseases) and cancers (glioma), in which both connexin dysfunction and pollutant involvement have been described. Based on these different aspects, the possible involvement of pollutant-inhibited gap junctions in brain disorders is discussed for prenatal and postnatal exposures.
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Affiliation(s)
- Marc Mesnil
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Norah Defamie
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Christian Naus
- Faculty of Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T1Z3, Canada;
| | - Denis Sarrouilhe
- Laboratoire de Physiologie Humaine, Faculté de Médecine et Pharmacie, 6 rue de La Milétrie, bât D1, TSA 51115, 86073 Poitiers, France
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Revisiting Traumatic Brain Injury: From Molecular Mechanisms to Therapeutic Interventions. Biomedicines 2020; 8:biomedicines8100389. [PMID: 33003373 PMCID: PMC7601301 DOI: 10.3390/biomedicines8100389] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 09/25/2020] [Accepted: 09/26/2020] [Indexed: 12/15/2022] Open
Abstract
Studying the complex molecular mechanisms involved in traumatic brain injury (TBI) is crucial for developing new therapies for TBI. Current treatments for TBI are primarily focused on patient stabilization and symptom mitigation. However, the field lacks defined therapies to prevent cell death, oxidative stress, and inflammatory cascades which lead to chronic pathology. Little can be done to treat the mechanical damage that occurs during the primary insult of a TBI; however, secondary injury mechanisms, such as inflammation, blood-brain barrier (BBB) breakdown, edema formation, excitotoxicity, oxidative stress, and cell death, can be targeted by therapeutic interventions. Elucidating the many mechanisms underlying secondary injury and studying targets of neuroprotective therapeutic agents is critical for developing new treatments. Therefore, we present a review on the molecular events following TBI from inflammation to programmed cell death and discuss current research and the latest therapeutic strategies to help understand TBI-mediated secondary injury.
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Kocovic DM, Limaye PV, Colburn LCH, Singh MB, Milosevic MM, Tadic J, Petronijevic M, Vrzic-Petronijevic S, Andjus PR, Antic SD. Cadmium versus Lanthanum Effects on Spontaneous Electrical Activity and Expression of Connexin Isoforms Cx26, Cx36, and Cx45 in the Human Fetal Cortex. Cereb Cortex 2020; 30:1244-1259. [PMID: 31408166 PMCID: PMC7132928 DOI: 10.1093/cercor/bhz163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/25/2019] [Accepted: 06/25/2019] [Indexed: 12/29/2022] Open
Abstract
Electrical activity is important for brain development. In brain slices, human subplate neurons exhibit spontaneous electrical activity that is highly sensitive to lanthanum. Based on the results of pharmacological experiments in human fetal tissue, we hypothesized that hemichannel-forming connexin (Cx) isoforms 26, 36, and 45 would be expressed on neurons in the subplate (SP) zone. RNA sequencing of dissected human cortical mantles at ages of 17-23 gestational weeks revealed that Cx45 has the highest expression, followed by Cx36 and Cx26. The levels of Cx and pannexin expression between male and female fetal cortices were not significantly different. Immunohistochemical analysis detected Cx45- and Cx26-expressing neurons in the upper segment of the SP zone. Cx45 was present on the cell bodies of human SP neurons, while Cx26 was found on both cell bodies and dendrites. Cx45, Cx36, and Cx26 were strongly expressed in the cortical plate, where newborn migrating neurons line up to form cortical layers. New information about the expression of 3 "neuronal" Cx isoforms in each cortical layer/zone (e.g., SP, cortical plate) and pharmacological data with cadmium and lanthanum may improve our understanding of the cellular mechanisms underlying neuronal development in human fetuses and potential vulnerabilities.
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Affiliation(s)
- Dusica M Kocovic
- Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
| | - Pallavi V Limaye
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Lauren C H Colburn
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Mandakini B Singh
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Milena M Milosevic
- Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Jasmina Tadic
- Faculty of Medicine, University of Belgrade, Belgrade 11000, Serbia
| | | | | | - Pavle R Andjus
- Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
| | - Srdjan D Antic
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
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12
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Wang R, Yang Y, Xiao M, Guo B, Liu W, Wang H. Neonatal Inhibition of Connexin 36 Ameliorates Fetal Brain Injury Induced by Maternal Noninfectious Fever in Mice. Dev Neurosci 2019; 41:94-101. [PMID: 31112950 DOI: 10.1159/000499735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 03/19/2019] [Indexed: 11/19/2022] Open
Abstract
Prenatal fever could result in brain function impairments in the offspring. The present study investigated the effect of interleukin-6 (IL-6)-induced maternal fever on the offspring and the involvement of connexin 36 in this process. Pregnant C57BL/6J mice were injected with IL-6 on gestational day 15. The levels of iNOS and COX-2 were measured as an index of neuroinflammation in the brain of newborn pups. Offspring were treated with the connexin 36 (Cx36) inhibitor mefloquine at postnatal day (P)1-P3 or at P40-P42. Rotarod, grip traction, and foot fault tests were carried out to evaluate the motor behavior of adult offspring. Injection of IL-6 led to an elevation of the core temperature in the pregnant dams. Offspring of these dams showed significantly increased COX-2 and iNOS mRNA expression and protein levels in the whole-brain samples and significantly increased Cx36 in the cerebellum. Moreover, offspring of these dams showed motor deficits at an adult age. Neonatal administration of the Cx36 inhibitor mefloquine could prevent these motor deficits. Maternal fever during pregnancy induced by IL-6 injection could lead to neuroinflammation and motor deficits in the offspring. Neonatal inhibition of Cx36 could ameliorate the motor deficits in the offspring, indicating an involvement of Cx36 in the IL-6-induced maternal fever.
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Affiliation(s)
- Ruifen Wang
- Cangzhou Central Hospital of Hebei Province, Cangzhou, China,
| | - Yueqing Yang
- Cangzhou Central Hospital of Hebei Province, Cangzhou, China
| | - Min Xiao
- Cangzhou Central Hospital of Hebei Province, Cangzhou, China
| | - Binfang Guo
- Cangzhou Central Hospital of Hebei Province, Cangzhou, China
| | - Weili Liu
- Cangzhou Central Hospital of Hebei Province, Cangzhou, China
| | - Haiyan Wang
- Cangzhou Central Hospital of Hebei Province, Cangzhou, China
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13
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Haynes HR, Scott HL, Killick-Cole CL, Shaw G, Brend T, Hares KM, Redondo J, Kemp KC, Ballesteros LS, Herman A, Cordero-Llana O, Singleton WG, Mills F, Batstone T, Bulstrode H, Kauppinen RA, Wurdak H, Uney JB, Short SC, Wilkins A, Kurian KM. shRNA-mediated PPARα knockdown in human glioma stem cells reduces in vitro proliferation and inhibits orthotopic xenograft tumour growth. J Pathol 2018; 247:422-434. [PMID: 30565681 PMCID: PMC6462812 DOI: 10.1002/path.5201] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/18/2018] [Accepted: 11/13/2018] [Indexed: 12/12/2022]
Abstract
The overall survival for patients with primary glioblastoma is very poor. Glioblastoma contains a subpopulation of glioma stem cells (GSC) that are responsible for tumour initiation, treatment resistance and recurrence. PPARα is a transcription factor involved in the control of lipid, carbohydrate and amino acid metabolism. We have recently shown that PPARα gene and protein expression is increased in glioblastoma and has independent clinical prognostic significance in multivariate analyses. In this work, we report that PPARα is overexpressed in GSC compared to foetal neural stem cells. To investigate the role of PPARα in GSC, we knocked down its expression using lentiviral transduction with short hairpin RNA (shRNA). Transduced GSC were tagged with luciferase and stereotactically xenografted into the striatum of NOD-SCID mice. Bioluminescent and magnetic resonance imaging showed that knockdown (KD) of PPARα reduced the tumourigenicity of GSC in vivo. PPARα-expressing control GSC xenografts formed invasive histological phenocopies of human glioblastoma, whereas PPARα KD GSC xenografts failed to establish viable intracranial tumours. PPARα KD GSC showed significantly reduced proliferative capacity and clonogenic potential in vitro with an increase in cellular senescence. In addition, PPARα KD resulted in significant downregulation of the stem cell factors c-Myc, nestin and SOX2. This was accompanied by downregulation of the PPARα-target genes and key regulators of fatty acid oxygenation ACOX1 and CPT1A, with no compensatory increase in glycolytic flux. These data establish the aberrant overexpression of PPARα in GSC and demonstrate that this expression functions as an important regulator of tumourigenesis, linking self-renewal and the malignant phenotype in this aggressive cancer stem cell subpopulation. We conclude that targeting GSC PPARα expression may be a therapeutically beneficial strategy with translational potential as an adjuvant treatment. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Harry R Haynes
- Brain Tumour Research Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.,Department of Cellular Pathology, North Bristol NHS Trust, Bristol, UK
| | - Helen L Scott
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Clare L Killick-Cole
- Functional Neurosurgery Research Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Gary Shaw
- Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK
| | - Tim Brend
- Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK
| | - Kelly M Hares
- Multiple Sclerosis and Stem Cell Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Juliana Redondo
- Multiple Sclerosis and Stem Cell Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Kevin C Kemp
- Multiple Sclerosis and Stem Cell Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Lorena S Ballesteros
- Flow Cytometry Facility, School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Andrew Herman
- Flow Cytometry Facility, School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Oscar Cordero-Llana
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - William G Singleton
- Functional Neurosurgery Research Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK.,Department of Neurosurgery, North Bristol NHS Trust, Bristol, UK
| | - Francesca Mills
- Department of Clinical Biochemistry, North Bristol NHS Trust, Bristol, UK
| | - Tom Batstone
- Bioinformatics Facility, School of Biological Sciences, University of Bristol, Bristol, UK
| | - Harry Bulstrode
- Department of Clinical Neuroscience and Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Risto A Kauppinen
- Clinical Research and Imaging Centre, University of Bristol, Bristol, UK
| | - Heiko Wurdak
- Stem Cells and Brain Tumour Group, Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK
| | - James B Uney
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Susan C Short
- Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK
| | - Alastair Wilkins
- Multiple Sclerosis and Stem Cell Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
| | - Kathreena M Kurian
- Brain Tumour Research Group, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
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14
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Lo Furno D, Mannino G, Pellitteri R, Zappalà A, Parenti R, Gili E, Vancheri C, Giuffrida R. Conditioned Media From Glial Cells Promote a Neural-Like Connexin Expression in Human Adipose-Derived Mesenchymal Stem Cells. Front Physiol 2018; 9:1742. [PMID: 30555356 PMCID: PMC6282092 DOI: 10.3389/fphys.2018.01742] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 11/19/2018] [Indexed: 12/12/2022] Open
Abstract
The expression of neuronal and glial connexins (Cxs) has been evaluated in adipose-derived mesenchymal stem cells (ASCs) whose neural differentiation was promoted by a conditioned medium (CM) obtained from cultures of olfactory ensheathing cells (OECs) or Schwann cells (SCs). By immunocytochemistry and flow cytometer analysis it was found that Cx43 was already considerably expressed in naïve ASCs and further increased after 24 h and 7 days from CM exposition. Cx32 and Cx36 were significantly improved in conditioned cultures compared to control ASCs, whereas a decreased expression was noticed in the absence of CM treatments. Cx47 was virtually absent in any conditions. Altogether, high basal levels and induced increases of Cx43 expression suggest a potential attitude of ASCs toward an astrocyte differentiation, whereas the lack of Cx47 would indicate a poor propensity of ASCs to become oligodendrocytes. CM-evoked Cx32 and Cx36 increases showed that a neuronal- or a SC-like differentiation can be promoted by using this strategy. Results further confirm that environmental cues can favor an ASC neural differentiation, either as neuronal or glial elements. Of note, the use of glial products present in CM rather than the addition of chemical agents to achieve such differentiation would resemble "more physiological" conditions of differentiation. As a conclusion, the overexpression of typical neural Cxs would indicate the potential capability of neural-like ASCs to interact with neighboring neural cells and microenvironment.
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Affiliation(s)
- Debora Lo Furno
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Giuliana Mannino
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Rosalia Pellitteri
- Institute of Neurological Sciences, National Research Council, Catania, Italy
| | - Agata Zappalà
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Rosalba Parenti
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
| | - Elisa Gili
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Carlo Vancheri
- Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Rosario Giuffrida
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, Catania, Italy
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15
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Meda P. Gap junction proteins are key drivers of endocrine function. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:124-140. [PMID: 28284720 DOI: 10.1016/j.bbamem.2017.03.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 03/03/2017] [Accepted: 03/06/2017] [Indexed: 01/07/2023]
Abstract
It has long been known that the main secretory cells of exocrine and endocrine glands are connected by gap junctions, made by a variety of connexin species that ensure their electrical and metabolic coupling. Experiments in culture systems and animal models have since provided increasing evidence that connexin signaling contributes to control the biosynthesis and release of secretory products, as well as to the life and death of secretory cells. More recently, genetic studies have further provided the first lines of evidence that connexins also control the function of human glands, which are central to the pathogenesis of major endocrine diseases. Here, we summarize the recent information gathered on connexin signaling in these systems, since the last reviews on the topic, with particular regard to the pancreatic beta cells which produce insulin, and the renal cells which produce renin. These cells are keys to the development of various forms of diabetes and hypertension, respectively, and combine to account for the exploding, worldwide prevalence of the metabolic syndrome. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Paolo Meda
- Department of Cell Physiology and Metabolism, University of Geneva Medical School, Switzerland.
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16
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Lemcke H, Peukert J, Voronina N, Skorska A, Steinhoff G, David R. Applying 3D-FRAP microscopy to analyse gap junction-dependent shuttling of small antisense RNAs between cardiomyocytes. J Mol Cell Cardiol 2016; 98:117-27. [DOI: 10.1016/j.yjmcc.2016.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 07/06/2016] [Accepted: 07/28/2016] [Indexed: 12/20/2022]
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17
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Yao XH, Wang M, He XN, He F, Zhang SQ, Lu W, Qiu ZL, Yu YC. Electrical coupling regulates layer 1 interneuron microcircuit formation in the neocortex. Nat Commun 2016; 7:12229. [PMID: 27510304 PMCID: PMC4987578 DOI: 10.1038/ncomms12229] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 06/15/2016] [Indexed: 02/06/2023] Open
Abstract
The coexistence of electrical and chemical synapses among interneurons is essential for interneuron function in the neocortex. However, it remains largely unclear whether electrical coupling between interneurons influences chemical synapse formation and microcircuit assembly during development. Here, we show that electrical and GABAergic chemical connections robustly develop between interneurons in neocortical layer 1 over a similar time course. Electrical coupling promotes action potential generation and synchronous firing between layer 1 interneurons. Furthermore, electrically coupled interneurons exhibit strong GABA-A receptor-mediated synchronous synaptic activity. Disruption of electrical coupling leads to a loss of bidirectional, but not unidirectional, GABAergic connections. Moreover, a reduction in electrical coupling induces an increase in excitatory synaptic inputs to layer 1 interneurons. Together, these findings strongly suggest that electrical coupling between neocortical interneurons plays a critical role in regulating chemical synapse development and precise formation of circuits.
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Affiliation(s)
- Xing-Hua Yao
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Min Wang
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Xiang-Nan He
- Centre for Computational Systems Biology and the School of Mathematical Sciences, Fudan University, Shanghai 200433, China
| | - Fei He
- Stem Cell Translational Research Center, Tongji Hospital, Tongji University School of Medicine, Shanghai 200092, China
| | - Shu-Qing Zhang
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Wenlian Lu
- Centre for Computational Systems Biology and the School of Mathematical Sciences, Fudan University, Shanghai 200433, China
| | - Zi-Long Qiu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and University of Chinese Academy of Sciences, 320 Yue-Yang Road, Shanghai 200031, China
| | - Yong-Chun Yu
- Institute of Neurobiology, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
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18
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Connexin 50 modulates Sox2 expression in spinal-cord-derived ependymal stem/progenitor cells. Cell Tissue Res 2016; 365:295-307. [PMID: 27221278 DOI: 10.1007/s00441-016-2421-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 05/01/2016] [Indexed: 12/23/2022]
Abstract
Ion channels included in the family of Connexins (Cx) have been reported to influence the secondary expansion of traumatic spinal cord injury (SCI) and neuropathic pain following SCI. However, Cxs also contribute to spinal cord neurogenesis during the remyelinating process and functional recovery after SCI. Certain Cxs have been recently related to the control of cell proliferation and the differentiation of neuronal progenitors. Adult spinal-cord-derived ependymal stem progenitor cells (epSPC) show high expression levels of Cx50 in non-pathological conditions and lower expression when they actively proliferate after injury (epSPCi). We explore the role of Cx50 in the ependymal population in the modulation of Sox2, a crucial factor of neural progenitor self-renewal and a promising target for promoting neuronal-cell-fate induction for neuronal tissue repair. Short-interfering-RNA ablation or over-expression of Cx50 regulates the expression of Sox2 in both epSPC and epSPCi. Interestingly, Cx50 and Sox2 co-localize at the nucleus indicating a potential role for this ion channel beyond cell-to-cell communication in the spinal cord. In vivo and in vitro experiments with Clotrimazole, a specific pharmacological modulator of Cx50, show the convergent higher expression of Cx50 and Sox2 in the isolated epSPC/epSPCi and in spinal cord tissue. Therefore, the pharmacological modulation of Cx50 might constitute an interesting mechanism for Sox2 induction to modulate the endogenous regenerative potential of neuronal tissue with a potential application in regenerative therapies.
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19
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Abstract
Connexins and pannexins share very similar structures and functions; they also exhibit overlapping expression in many stages of neuronal development. Here, we review evidence implicating connexin- and pannexin-mediated communication in the regulation of the birth and development of neurons, specifically Cx26, Cx30, Cx32, Cx36, Cx43, Cx45, Panx1, and Panx2. We begin by dissecting the involvement of these proteins in the generation and development of new neurons in the embryonic, postnatal, and adult brain. Next we briefly outline common mechanisms employed by both pannexins and connexins in these roles, including modulation of purinergic receptor signalling and signalling nexus functions. Throughout this review we highlight developing themes as well as important gaps in knowledge to be bridged.
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Affiliation(s)
- Leigh Anne Swayne
- />Division of Medical Sciences, University of Victoria, Medical Sciences Building Rm 224, 3800 Finnerty Rd, Victoria, BC V8P5C2 Canada
| | - Steffany A. L. Bennett
- />Department of Biochemistry, Microbiology and Immunology, Neural Regeneration Laboratory, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON Canada
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20
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Rodriguez-Jimenez FJ, Alastrue-Agudo A, Stojkovic M, Erceg S, Moreno-Manzano V. Connexin 50 Expression in Ependymal Stem Progenitor Cells after Spinal Cord Injury Activation. Int J Mol Sci 2015; 16:26608-18. [PMID: 26561800 PMCID: PMC4661840 DOI: 10.3390/ijms161125981] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 10/26/2015] [Accepted: 10/30/2015] [Indexed: 12/28/2022] Open
Abstract
Ion channels included in the family of Connexins (Cx) help to control cell proliferation and differentiation of neuronal progenitors. Here we explored the role of Connexin 50 (Cx50) in cell fate modulation of adult spinal cord derived neural precursors located in the ependymal canal (epSPC). epSPC from non-injured animals showed high expression levels of Cx50 compared to epSPC from animals with spinal cord injury (SCI) (epSPCi). When epSPC or epSPCi were induced to spontaneously differentiate in vitro we found that Cx50 favors glial cell fate, since higher expression levels, endogenous or by over-expression of Cx50, augmented the expression of the astrocyte marker GFAP and impaired the neuronal marker Tuj1. Cx50 was found in both the cytoplasm and nucleus of glial cells, astrocytes and oligodendrocyte-derived cells. Similar expression patterns were found in primary cultures of mature astrocytes. In addition, opposite expression profile for nuclear Cx50 was observed when epSPC and activated epSPCi were conducted to differentiate into mature oligodendrocytes, suggesting a different role for this ion channel in spinal cord beyond cell-to-cell communication. In vivo detection of Cx50 by immunohistochemistry showed a defined location in gray matter in non-injured tissues and at the epicenter of the injury after SCI. epSPCi transplantation, which accelerates locomotion regeneration by a neuroprotective effect after acute SCI is associated with a lower signal of Cx50 within the injured area, suggesting a minor or detrimental contribution of this ion channel in spinal cord regeneration by activated epSPCi.
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Affiliation(s)
| | - Ana Alastrue-Agudo
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, Valencia E-46012, Spain.
| | - Miodrag Stojkovic
- Spebo Medical, 16000 Leskovac, Serbia.
- Human Genetics, Faculty of Medical Sciences, University of Kragujevac, 34000 Kragujevac, Serbia.
| | - Slaven Erceg
- Stem Cell Therapies in Neurodegenerative Diseases Laboratory, Centro de Investigación Príncipe Felipe, Valencia E-46012, Spain.
| | - Victoria Moreno-Manzano
- Neuronal and Tissue Regeneration Laboratory, Centro de Investigación Príncipe Felipe, Valencia E-46012, Spain.
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21
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Raslan A, Hainz N, Beckmann A, Tschernig T, Meier C. Pannexin-1 expression in developing mouse nervous system: new evidence for expression in sensory ganglia. Cell Tissue Res 2015; 364:29-41. [PMID: 26453396 DOI: 10.1007/s00441-015-2294-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/07/2015] [Indexed: 12/14/2022]
Abstract
Pannexin1 (Panx1) is one of three members of the pannexin protein family. The expression of Panx1 mRNA has been extensively investigated from late embryonic to adult stages. In contrast, expression during early embryonic development is largely unknown. Our aim is to examine the temporal and spatial expression of Panx1 in mouse embryonic development by focusing on embryonic days (E) 9.5 to 12.5. Whole embryos are investigated in order to provide a comprehensive survey. Analyses were performed at the mRNA level by using reverse transcription plus the polymerase chain reaction and whole-mount in situ hybridization. Panx1 mRNA was detected in the heads and bodies of embryos at all developmental stages investigated (E9.5, E10.5, E11.5, E12.5). In particular, the nervous system expressed Panx1 at an early time point. Interestingly, Panx1 expression was found in afferent ganglia of the cranial nerves and spinal cord. This finding is of particular interest in the context of neuropathic pain and other Panx1-related neurological disorders. Our study shows, for the first time, that Panx1 is expressed in the central and peripheral nervous system during early developmental stages. The consequences of Panx1 deficiency or inhibition in a number of experimental paradigms might therefore be predicated on changes during early development.
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Affiliation(s)
- Abdulrahman Raslan
- Department of Anatomy and Cell Biology, Saarland University, Building 61, 66424, Homburg, Saar, Germany
| | - Nadine Hainz
- Department of Anatomy and Cell Biology, Saarland University, Building 61, 66424, Homburg, Saar, Germany
| | - Anja Beckmann
- Department of Anatomy and Cell Biology, Saarland University, Building 61, 66424, Homburg, Saar, Germany
| | - Thomas Tschernig
- Department of Anatomy and Cell Biology, Saarland University, Building 61, 66424, Homburg, Saar, Germany
| | - Carola Meier
- Department of Anatomy and Cell Biology, Saarland University, Building 61, 66424, Homburg, Saar, Germany.
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22
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Decrock E, De Bock M, Wang N, Bultynck G, Giaume C, Naus CC, Green CR, Leybaert L. Connexin and pannexin signaling pathways, an architectural blueprint for CNS physiology and pathology? Cell Mol Life Sci 2015; 72:2823-51. [PMID: 26118660 PMCID: PMC11113968 DOI: 10.1007/s00018-015-1962-7] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 02/06/2023]
Abstract
The central nervous system (CNS) is composed of a highly heterogeneous population of cells. Dynamic interactions between different compartments (neuronal, glial, and vascular systems) drive CNS function and allow to integrate and process information as well as to respond accordingly. Communication within this functional unit, coined the neuro-glio-vascular unit (NGVU), typically relies on two main mechanisms: direct cell-cell coupling via gap junction channels (GJCs) and paracrine communication via the extracellular compartment, two routes to which channels composed of transmembrane connexin (Cx) or pannexin (Panx) proteins can contribute. Multiple isoforms of both protein families are present in the CNS and each CNS cell type is characterized by a unique Cx/Panx portfolio. Over the last two decades, research has uncovered a multilevel platform via which Cxs and Panxs can influence different cellular functions within a tissue: (1) Cx GJCs enable a direct cell-cell communication of small molecules, (2) Cx hemichannels and Panx channels can contribute to autocrine/paracrine signaling pathways, and (3) different structural domains of these proteins allow for channel-independent functions, such as cell-cell adhesion, interactions with the cytoskeleton, and the activation of intracellular signaling pathways. In this paper, we discuss current knowledge on their multifaceted contribution to brain development and to specific processes in the NGVU, including synaptic transmission and plasticity, glial signaling, vasomotor control, and blood-brain barrier integrity in the mature CNS. By highlighting both physiological and pathological conditions, it becomes evident that Cxs and Panxs can play a dual role in the CNS and that an accurate fine-tuning of each signaling mechanism is crucial for normal CNS physiology.
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Affiliation(s)
- Elke Decrock
- Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B, 3rd floor), 9000 Ghent, Belgium
| | - Marijke De Bock
- Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B, 3rd floor), 9000 Ghent, Belgium
| | - Nan Wang
- Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B, 3rd floor), 9000 Ghent, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Louvain, Belgium
| | - 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, 75231 Paris Cedex 05, France
- University Pierre et Marie
Curie, ED, N°158, 75005 Paris, France
- MEMOLIFE Laboratory of Excellence and Paris Science Lettre Research University, 75005 Paris, France
| | - Christian C. Naus
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC V6T 1Z3 Canada
| | - Colin R. Green
- Department of Ophthalmology, The University of Auckland, Auckland, New Zealand
| | - Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B, 3rd floor), 9000 Ghent, Belgium
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23
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Theotokis P, Kleopa KA, Touloumi O, Lagoudaki R, Lourbopoulos A, Nousiopoulou E, Kesidou E, Poulatsidou KN, Dardiotis E, Hadjigeorgiou G, Karacostas D, Cifuentes-Diaz C, Irinopoulou T, Grigoriadis N. Connexin43 and connexin47 alterations after neural precursor cells transplantation in experimental autoimmune encephalomyelitis. Glia 2015; 63:1772-83. [PMID: 25914045 DOI: 10.1002/glia.22843] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 03/31/2015] [Accepted: 04/02/2015] [Indexed: 01/19/2023]
Abstract
Exogenous transplanted neural precursor cells (NPCs) exhibit miscellaneous immune-modulatory effects in models of autoimmune demyelination. However, the regional interactions of NPCs with the host brain tissue in remissive inflammatory events have not been adequately studied. In this study we used the chronic MOG-induced Experimental Autoimmune Encephalomyelitis (EAE) model in C57BL/six mice. Based on previous data, we focused on neuropathology at Day 50 post-induction (D50) and studied the expression of connexin43 (Cx43) and Cx47, two of the main glial gap junction (GJ) proteins, in relation to the intraventricular transplantation of GFP(+) NPCs and their integration with the host tissue. By D50, NPCs had migrated intraparenchymally and were found in the corpus callosum at the level of the lateral ventricles and hippocampus. The majority of GFP(+) cells differentiated with simple or ramified processes expressing mainly markers of mature GLIA (GFAP and NogoA) and significantly less of precursor glial cells. GFP(+) NPCs expressed connexins and formed GJs around the hippocampus more than lateral ventricles. The presence of NPCs did not alter the increase in Cx43 GJ plaques at D50 EAE, but prevented the reduction of oligodendrocytic Cx47, increased the number of oligodendrocytes, local Cx47 levels and Cx47 GJ plaques per cell. These findings suggest that transplanted NPCs may have multiple effects in demyelinating pathology, including differentiation and direct integration into the panglial syncytium, as well as amelioration of oligodendrocyte GJ loss, increasing the supply of potent myelinating cells to the demyelinated tissue.
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Affiliation(s)
- Paschalis Theotokis
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Kleopas A Kleopa
- Neurology Clinics and Neuroscience Laboratory, the Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Olga Touloumi
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Roza Lagoudaki
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Athanasios Lourbopoulos
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Evangelia Nousiopoulou
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Evangelia Kesidou
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Kyriaki-Nepheli Poulatsidou
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Efthimios Dardiotis
- Department of Neurology, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | | | - Dimitris Karacostas
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | | | | | - Nikolaos Grigoriadis
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
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Aasen T. Connexins: junctional and non-junctional modulators of proliferation. Cell Tissue Res 2014; 360:685-99. [PMID: 25547217 DOI: 10.1007/s00441-014-2078-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 11/14/2014] [Indexed: 12/11/2022]
Abstract
Mounting evidence indicates that dysregulation of gap junctions and their structural subunits-connexins-often occurs in, and sometimes causes, a variety of proliferative disorders, including cancer. Connexin-mediated regulation of cell proliferation is complex and may involve modulation of gap junction intercellular communication (GJIC), hemichannel signalling, or gap junction-independent paths. However, the exact mechanisms linking connexins to proliferation remain poorly defined and a number of contradictory studies report both pro- and anti-proliferative effects, effects that often depend on the cell or tissue type or the microenvironment. The present review covers junctional and non-junctional regulation of proliferation by connexins, with a particular emphasis on their association with cancer.
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Affiliation(s)
- Trond Aasen
- Molecular Pathology Group, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Passeig Vall d'Hebron 119-129, Barcelona, 08035, Spain,
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25
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Sart S, Yan Y, Li Y. The microenvironment of embryoid bodies modulated the commitment to neural lineage postcryopreservation. Tissue Eng Part C Methods 2014; 21:356-66. [PMID: 25187378 DOI: 10.1089/ten.tec.2014.0276] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neural progenitor cells are usually derived from pluripotent stem cells (PSCs) through the formation of embryoid bodies (EBs), the three-dimensional (3D) aggregate-like structure mimicking embryonic development. Cryo-banking of EBs is a critical step for sample storage, process monitoring, and preservation of intermediate cell populations during the lengthy differentiation procedure of PSCs. However, the impact of microenvironment (including 3D cell organization and biochemical factors) of EBs on neural lineage commitment postcryopreservation has not been well understood. In this study, intact EBs (I-E) and dissociated EBs (D-E) were compared for the recovery and neural differentiation after cryopreservation. I-E group showed the enhanced viability and recovery upon thaw compared with D-E group due to the preservation of extracellular matrix, cell-cell contacts, and F-actin organization. Moreover, both I-E and D-E groups showed the increased neuronal differentiation and D-E group also showed the enhanced astrocyte differentiation after thaw, probably due to the modulation of cellular redox state indicated by the expression of reactive oxygen species. In addition, mesenchymal stem cell secretome, known to bear a broad spectrum of protective factors, enhanced EB recovery. Taken together, EB microenvironment plays a critical role in the recovery and neural differentiation postcryopreservation.
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Affiliation(s)
- Sébastien Sart
- Department of Chemical and Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University , Tallahassee, Florida
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26
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Carlisle TC, Ribera AB. Connexin 35b expression in the spinal cord of Danio rerio embryos and larvae. J Comp Neurol 2014; 522:861-75. [PMID: 23939687 DOI: 10.1002/cne.23449] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/10/2013] [Accepted: 08/02/2013] [Indexed: 11/11/2022]
Abstract
Electrical synapses are expressed prominently in the developing and mature nervous systems. Unlike chemical synapses, little is known about the developmental role of electrical synapses, reflecting the limitations imposed by the lack of selective pharmacological blockers. At a molecular level, the building blocks of electrical synapses are connexin proteins. In this study, we report the expression pattern for neuronally expressed connexin 35b (cx35b), the zebrafish orthologue of mammalian connexin (Cx) 36. We find that cx35b is expressed at the time of neural induction, indicating a possible early role in neural progenitor cells. Additionally, cx35b localizes to the ventral spinal cord during embryonic and early larval stages. We detect cx35b mRNA in secondary motor neurons (SMNs) and interneurons. We identified the premotor circumferential descending (CiD) interneuron as one interneuron subtype expressing cx35b. In addition, cx35b is present in other ventral interneurons of unknown subtype(s). This early expression of cx35b in SMNs and CiDs suggests a possible role in motor network function during embryonic and larval stages.
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Affiliation(s)
- Tara C Carlisle
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045; Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045; Colorado Clinical and Translational Sciences Institute, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045; Medical Scientist Training Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, 80045
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27
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Takeuchi H, Suzumura A. Gap junctions and hemichannels composed of connexins: potential therapeutic targets for neurodegenerative diseases. Front Cell Neurosci 2014; 8:189. [PMID: 25228858 PMCID: PMC4151093 DOI: 10.3389/fncel.2014.00189] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/19/2014] [Indexed: 12/03/2022] Open
Abstract
Microglia are macrophage-like resident immune cells that contribute to the maintenance of homeostasis in the central nervous system (CNS). Abnormal activation of microglia can cause damage in the CNS, and accumulation of activated microglia is a characteristic pathological observation in neurologic conditions such as trauma, stroke, inflammation, epilepsy, and neurodegenerative diseases. Activated microglia secrete high levels of glutamate, which damages CNS cells and has been implicated as a major cause of neurodegeneration in these conditions. Glutamate-receptor blockers and microglia inhibitors (e.g., minocycline) have been examined as therapeutic candidates for several neurodegenerative diseases; however, these compounds exerted little therapeutic benefit because they either perturbed physiological glutamate signals or suppressed the actions of protective microglia. The ideal therapeutic approach would hamper the deleterious roles of activated microglia without diminishing their protective effects. We recently found that abnormally activated microglia secrete glutamate via gap-junction hemichannels on the cell surface. Moreover, administration of gap-junction inhibitors significantly suppressed excessive microglial glutamate release and improved disease symptoms in animal models of neurologic conditions such as stroke, multiple sclerosis, amyotrophic lateral sclerosis, and Alzheimer's disease. Recent evidence also suggests that neuronal and glial communication via gap junctions amplifies neuroinflammation and neurodegeneration. Elucidation of the precise pathologic roles of gap junctions and hemichannels may lead to a novel therapeutic strategies that can slow and halt the progression of neurodegenerative diseases.
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Affiliation(s)
- Hideyuki Takeuchi
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University Nagoya, Japan
| | - Akio Suzumura
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University Nagoya, Japan
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28
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de Carvalho D, Patrone LGA, Taxini CL, Biancardi V, Vicente MC, Gargaglioni LH. Neurochemical and electrical modulation of the locus coeruleus: contribution to CO2drive to breathe. Front Physiol 2014; 5:288. [PMID: 25183958 PMCID: PMC4135231 DOI: 10.3389/fphys.2014.00288] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 07/14/2014] [Indexed: 11/13/2022] Open
Abstract
The locus coeruleus (LC) is a dorsal pontine region, situated bilaterally on the floor of the fourth ventricle. It is considered to be the major source of noradrenergic innervation in the brain. These neurons are highly sensitive to CO2/pH, and chemical lesions of LC neurons largely attenuate the hypercapnic ventilatory response in unanesthetized adult rats. Developmental dysfunctions in these neurons are linked to pathological conditions such as Rett and sudden infant death syndromes, which can impair the control of the cardio-respiratory system. LC is densely innervated by fibers that contain glutamate, serotonin, and adenosine triphosphate, and these neurotransmitters strongly affect LC activity, including central chemoreflexes. Aside from neurochemical modulation, LC neurons are also strongly electrically coupled, specifically through gap junctions, which play a role in the CO2 ventilatory response. This article reviews the available data on the role of chemical and electrical neuromodulation of the LC in the control of ventilation.
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Affiliation(s)
- Débora de Carvalho
- Department of Animal Morphology and Physiology, Faculty of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista - São Paulo State University Jaboticabal, Brazil
| | - Luis G A Patrone
- Department of Animal Morphology and Physiology, Faculty of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista - São Paulo State University Jaboticabal, Brazil
| | - Camila L Taxini
- Department of Animal Morphology and Physiology, Faculty of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista - São Paulo State University Jaboticabal, Brazil
| | - Vivian Biancardi
- Department of Animal Morphology and Physiology, Faculty of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista - São Paulo State University Jaboticabal, Brazil
| | - Mariane C Vicente
- Department of Animal Morphology and Physiology, Faculty of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista - São Paulo State University Jaboticabal, Brazil
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Faculty of Agricultural and Veterinarian Sciences, Universidade Estadual Paulista - São Paulo State University Jaboticabal, Brazil
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29
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Castellano P, Eugenin EA. Regulation of gap junction channels by infectious agents and inflammation in the CNS. Front Cell Neurosci 2014; 8:122. [PMID: 24847208 PMCID: PMC4023065 DOI: 10.3389/fncel.2014.00122] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 04/17/2014] [Indexed: 01/04/2023] Open
Abstract
Gap junctions (GJs) are conglomerates of intercellular channels that connect the cytoplasm of two or more cells, and facilitate the transfer of ions and small molecules, including second messengers, resulting in metabolic and electrical coordination. In general, loss of gap junctional communication (GJC) has been associated with cellular damage and inflammation resulting in compromise of physiological functions. Recently, it has become evident that GJ channels also play a critical role in the pathogenesis of infectious diseases and associated inflammation. Several pathogens use the transfer of intracellular signals through GJ channels to spread infection and toxic signals that amplify inflammation to neighboring cells. Thus, identification of the mechanisms by which several infectious agents alter GJC could result in new potential therapeutic approaches to reduce inflammation and their pathogenesis.
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Affiliation(s)
- Paul Castellano
- Public Health Research Institute (PHRI), New Jersey Medical School, Rutgers The State University of New Jersey Newark, NJ, USA ; Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers The State University of New Jersey Newark, NJ, USA
| | - Eliseo A Eugenin
- Public Health Research Institute (PHRI), New Jersey Medical School, Rutgers The State University of New Jersey Newark, NJ, USA ; Department of Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers The State University of New Jersey Newark, NJ, USA
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30
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Baker MW, Macagno ER. Control of neuronal morphology and connectivity: Emerging developmental roles for gap junctional proteins. FEBS Lett 2014; 588:1470-9. [DOI: 10.1016/j.febslet.2014.02.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 11/25/2022]
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31
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Rinaldi F, Hartfield EM, Crompton LA, Badger JL, Glover CP, Kelly CM, Rosser AE, Uney JB, Caldwell MA. Cross-regulation of Connexin43 and β-catenin influences differentiation of human neural progenitor cells. Cell Death Dis 2014; 5:e1017. [PMID: 24457961 PMCID: PMC4040652 DOI: 10.1038/cddis.2013.546] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 10/30/2013] [Accepted: 11/04/2013] [Indexed: 12/03/2022]
Abstract
Connexin43 (Cx43) is the most widely and abundantly expressed gap junction (GJ) protein and it is strongly associated with the regulation of cell cycle progression. Emerging roles for Cx43 in cell adhesion and migration during neural differentiation have also been recently recognized, and this has emphasized the involvement of Cx43 in different physiological process beyond its role as a GJ protein. In this study, we explore the function of Cx43 in the differentiation of human neural progenitor cells (hNPCs) using viral vectors that mediate the overexpression or knockdown of the protein. Results showed that in the absence of this protein fetal cortex-derived hNPCs differentiated toward a neuronal phenotype at expenses of a glial phenotype. Furthermore, the silencing of Cx43 did not affect hNPC proliferation rate or numbers of apoptotic cells. The increase in the number of neurons was not recapitulated when GJ intercellular communications were pharmacologically blocked, and this suggested that Cx43 was influencing hNPCs differentiation with a GJ-independent effect. In addition, Cx43 knockdown significantly increased β-catenin signaling, which has been shown to regulate the transcription of pro-neuronal genes during embryonic neural development. Our results add further support to the hypothesis that Cx43 protein itself regulates key signaling pathways during development and neurogenesis beyond its role as GJ protein.
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Affiliation(s)
- F Rinaldi
- Stem Cells and Neuroregeneration Research Group, School of Clinical Sciences, Medical Sciences Building, University Walk, University of Bristol, Bristol, UK
| | - E M Hartfield
- Stem Cells and Neuroregeneration Research Group, School of Clinical Sciences, Medical Sciences Building, University Walk, University of Bristol, Bristol, UK
| | - L A Crompton
- Stem Cells and Neuroregeneration Research Group, School of Clinical Sciences, Medical Sciences Building, University Walk, University of Bristol, Bristol, UK
| | - J L Badger
- Stem Cells and Neuroregeneration Research Group, School of Clinical Sciences, Medical Sciences Building, University Walk, University of Bristol, Bristol, UK
| | - C P Glover
- Stem Cells and Neuroregeneration Research Group, School of Clinical Sciences, Medical Sciences Building, University Walk, University of Bristol, Bristol, UK
| | - C M Kelly
- Brain Repair Group, School of Biosciences, Life Science Building, University of Cardiff, Cardiff, UK
| | - A E Rosser
- Brain Repair Group, School of Biosciences, Life Science Building, University of Cardiff, Cardiff, UK
- Department of Neurology, School of Medicine, University of Cardiff, Cardiff, UK
| | - J B Uney
- Stem Cells and Neuroregeneration Research Group, School of Clinical Sciences, Medical Sciences Building, University Walk, University of Bristol, Bristol, UK
| | - M A Caldwell
- Stem Cells and Neuroregeneration Research Group, School of Clinical Sciences, Medical Sciences Building, University Walk, University of Bristol, Bristol, UK
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32
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Affiliation(s)
- Hideyuki Takeuchi
- Department of Neuroimmunology; Research Institute of Environmental Medicine; Nagoya University; Nagoya Japan
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33
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Neuronal gap junction coupling as the primary determinant of the extent of glutamate-mediated excitotoxicity. J Neural Transm (Vienna) 2013; 121:837-46. [PMID: 24178243 DOI: 10.1007/s00702-013-1109-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 10/16/2013] [Indexed: 01/12/2023]
Abstract
In the mammalian central nervous system (CNS), coupling of neurons by gap junctions (electrical synapses) increases during early postnatal development, then decreases, but increases in the mature CNS following neuronal injury, such as ischemia, traumatic brain injury and epilepsy. Glutamate-dependent neuronal death also occurs in the CNS during development and neuronal injury, i.e., at the time when neuronal gap junction coupling is increased. Here, we review our recent studies on regulation of neuronal gap junction coupling by glutamate in developing and injured neurons and on the role of gap junctions in neuronal cell death. A modified model of the mechanisms of glutamate-dependent neuronal death is discussed, which includes neuronal gap junction coupling as a critical part of these mechanisms.
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34
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Wan CK, O'Carroll SJ, Kim SL, Green CR, Nicholson LFB. Spatiotemporal changes in Cx30 and Cx43 expression during neuronal differentiation of P19 EC and NT2/D1 cells. CELL BIOLOGY INTERNATIONAL REPORTS 2013; 20:13-23. [PMID: 25505515 PMCID: PMC4255794 DOI: 10.1002/cbi3.10005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/17/2013] [Indexed: 12/23/2022]
Abstract
While connexins (Cxs) are thought to be involved in differentiation, their expression and role has yet to be fully elucidated. We investigated the temporal expression of Cx30, Cx36 and Cx43 in two in vitro models of neuronal differentiation: human NT2/D1 and murine P19 cells, and the spatial localisation of Cx30 and Cx43 in these models. A temporal Cx43 downregulation was confirmed in both cell lines during RA-induced neuronal differentiation using RT-PCR (P < 0.05) preceding an increase in neuronal doublecortin protein. RT-PCR showed Cx36 was upregulated twofold in NT2/D1 cells (P < 0.05) and sixfold in P19 cells (P < 0.001) during neuronal differentiation. Cx30 exhibited a transient peak in expression midway through the timecourse of differentiation increasing threefold in NT2/D1 cells (P < 0.001) and eightfold in P19 cells (P < 0.01). Qualitative immunocytochemistry was used to examine spatiotemporal patterns of Cx protein distribution alongside neuronal differentiation markers. The temporal immunolabelling pattern was similar to that seen using RT-PCR. Cx43 was observed intracellularly and on cell surfaces, while Cx30 was seen as puncta. Spatially Cx43 was seen on doublecortin-negative cells, which may indicate Cx43 downregulation is requisite for differentiation in these models. Conversely, Cx30 puncta were observed on doublecortin-positive and -negative cells in NT2/D1 cells and examination of the Cx30 peak showed puncta also localized to nestin-positive cells, with few puncta on MAP2-positive cells. In P19 cells Cx30 was localized on clusters of cells surrounded by MAP2- and doublecortin-positive processes. The expression pattern of Cx30 indicates a role in neuronal differentiation; the nature of that role warrants future investigation.
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Affiliation(s)
- Carthur K Wan
- Faculty of Medical and Health Sciences, Department of Anatomy with Radiology and Centre for Brain Research, The University of Auckland Auckland, 92019, New Zealand
| | - Simon J O'Carroll
- Faculty of Medical and Health Sciences, Department of Anatomy with Radiology and Centre for Brain Research, The University of Auckland Auckland, 92019, New Zealand
| | - Sue-Ling Kim
- Faculty of Medical and Health Sciences, Department of Anatomy with Radiology and Centre for Brain Research, The University of Auckland Auckland, 92019, New Zealand
| | - Colin R Green
- Faculty of Medical and Health Sciences, Department of Ophthalmology, The University of Auckland Auckland, 92019, New Zealand
| | - Louise F B Nicholson
- Faculty of Medical and Health Sciences, Department of Anatomy with Radiology and Centre for Brain Research, The University of Auckland Auckland, 92019, New Zealand
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Abstract
The presence of direct, cytoplasmatic, communication between neurons in the brain of vertebrates has been demonstrated a long time ago. These gap junctions have been characterized in many brain areas in terms of subunit composition, biophysical properties, neuronal connectivity patterns, and developmental regulation. Although interesting findings emerged, showing that different subunits are specifically regulated during development, or that excitatory and inhibitory neuronal networks exhibit various electrical connectivity patterns, gap junctions did not receive much further interest. Originally, it was believed that gap junctions represent simple passageways for electrical and biochemical coordination early in development. Today, we know that gap junction connectivity is tightly regulated, following independent developmental patterns for excitatory and inhibitory networks. Electrical connections are important for many specific functions of neurons, and are, for example, required for the development of neuronal stimulus tuning in the visual system. Here, we integrate the available data on neuronal connectivity and gap junction properties, as well as the most recent findings concerning the functional implications of electrical connections in the developing thalamus and neocortex.
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Affiliation(s)
- Dragos Niculescu
- Department of Synapse and Network Development, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
| | - Christian Lohmann
- Department of Synapse and Network Development, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
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36
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Lemcke H, Nittel ML, Weiss DG, Kuznetsov SA. Neuronal differentiation requires a biphasic modulation of gap junctional intercellular communication caused by dynamic changes of connexin43 expression. Eur J Neurosci 2013; 38:2218-28. [PMID: 23607708 DOI: 10.1111/ejn.12219] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 03/12/2013] [Accepted: 03/14/2013] [Indexed: 11/30/2022]
Abstract
It was suggested that gap junctional intercellular communication (GJIC) and connexin (Cx) proteins play a crucial role in cell proliferation and differentiation. However, the mechanisms of cell coupling in regulating cell fate during embryonic development are poorly understood. To study the role of GJIC in proliferation and differentiation, we used a human neural progenitor cell line derived from the ventral mesencephalon. Fluorescence recovery after photobleaching (FRAP) showed that dye coupling was extensive in proliferating cells but diminished after the induction of differentiation, as indicated by a 2.5-fold increase of the half-time of fluorescence recovery. Notably, recovery half-time decreased strongly (five-fold) in the later stage of differentiation. Western blot analysis revealed a similar time-dependent expression profile of Cx43, acting as the main gap junction-forming protein. Interestingly, large amounts of cytoplasmic Cx43 were retained mainly in the Golgi network during proliferation but decreased when differentiation was induced. Furthermore, down-regulation of Cx43 by small interfering RNA reduced functional cell coupling, which in turn resulted in a 50% decrease of both the proliferation rate and neuronal differentiation. Our findings suggest a dual function of Cx43 and GJIC in the neural development of ReNcell VM197 human progenitor cells. GJIC accompanied by high Cx43 expression is necessary (1) to maintain cells in a proliferative state and (2) to complete neuronal differentiation, including the establishment of a neural network. However, uncoupling of cells is crucial in the early stage of differentiation during cell fate commitment.
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Affiliation(s)
- Heiko Lemcke
- Department of Animal Physiology, Cell Biology and Biosystems Technology, Institute of Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, D-18059, Rostock, Germany
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37
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Belousov AB, Fontes JD. Neuronal gap junctions: making and breaking connections during development and injury. Trends Neurosci 2013; 36:227-36. [PMID: 23237660 PMCID: PMC3609876 DOI: 10.1016/j.tins.2012.11.001] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 11/02/2012] [Accepted: 11/02/2012] [Indexed: 01/08/2023]
Abstract
In the mammalian central nervous system (CNS), coupling of neurons by gap junctions (i.e., electrical synapses) and the expression of the neuronal gap junction protein, connexin 36 (Cx36), transiently increase during early postnatal development. The levels of both subsequently decline and remain low in the adult, confined to specific subsets of neurons. However, following neuronal injury [such as ischemia, traumatic brain injury (TBI), and epilepsy], the coupling and expression of Cx36 rise. Here we summarize new findings on the mechanisms of regulation of Cx36-containing gap junctions in the developing and mature CNS and following injury. We also review recent studies suggesting various roles for neuronal gap junctions and in particular their role in glutamate-mediated neuronal death.
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Affiliation(s)
- Andrei B Belousov
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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38
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Cigliola V, Chellakudam V, Arabieter W, Meda P. Connexins and β-cell functions. Diabetes Res Clin Pract 2013; 99:250-9. [PMID: 23176806 DOI: 10.1016/j.diabres.2012.10.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 10/15/2012] [Indexed: 11/20/2022]
Abstract
Proper functioning of pancreatic islets requires that numerous β-cells are properly coordinated. With evolution, many mechanisms have converged, which now allow individual β-cells to sense the state of activity of their neighbors as well as the changes taking place in the extracellular medium, and to regulate accordingly their own function. Here, we review one such mechanism for intercellular coordination, which depends on connexins. These integral membrane proteins accumulate at sites of close apposition between adjacent islet cell membranes, referred to as gap junctions. Recent evidence demonstrates that connexin-dependent signaling is relevant for the in vivo control of insulin biosynthesis and release, as well as for the survival of β-cells under stressing conditions. The data suggest that alterations of this signaling may be implicated in the β-cell alterations which characterize most forms of diabetes, raising the tantalizing possibility that targeting of the direct intercellular communications β-cells establish within each pancreatic islet may provide a novel, therapeutically useful strategy.
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Affiliation(s)
- Valentina Cigliola
- Department of Cell Physiology and Metabolism, University of Geneva School of Medicine, 1 rue Michel-Servet, Geneva, Switzerland
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39
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Meda P. Protein-mediated interactions of pancreatic islet cells. SCIENTIFICA 2013; 2013:621249. [PMID: 24278783 PMCID: PMC3820362 DOI: 10.1155/2013/621249] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 12/10/2012] [Indexed: 05/29/2023]
Abstract
The islets of Langerhans collectively form the endocrine pancreas, the organ that is soley responsible for insulin secretion in mammals, and which plays a prominent role in the control of circulating glucose and metabolism. Normal function of these islets implies the coordination of different types of endocrine cells, noticeably of the beta cells which produce insulin. Given that an appropriate secretion of this hormone is vital to the organism, a number of mechanisms have been selected during evolution, which now converge to coordinate beta cell functions. Among these, several mechanisms depend on different families of integral membrane proteins, which ensure direct (cadherins, N-CAM, occludin, and claudins) and paracrine communications (pannexins) between beta cells, and between these cells and the other islet cell types. Also, other proteins (integrins) provide communication of the different islet cell types with the materials that form the islet basal laminae and extracellular matrix. Here, we review what is known about these proteins and their signaling in pancreatic β -cells, with particular emphasis on the signaling provided by Cx36, given that this is the integral membrane protein involved in cell-to-cell communication, which has so far been mostly investigated for effects on beta cell functions.
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Affiliation(s)
- Paolo Meda
- Department of Cell Physiology and Metabolism, University of Geneva School of Medicine, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland
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Eugenin EA, Basilio D, Sáez JC, Orellana JA, Raine CS, Bukauskas F, Bennett MVL, Berman JW. The role of gap junction channels during physiologic and pathologic conditions of the human central nervous system. J Neuroimmune Pharmacol 2012; 7:499-518. [PMID: 22438035 PMCID: PMC3638201 DOI: 10.1007/s11481-012-9352-5] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 02/28/2012] [Indexed: 12/15/2022]
Abstract
Gap junctions (GJs) are expressed in most cell types of the nervous system, including neuronal stem cells, neurons, astrocytes, oligodendrocytes, cells of the blood brain barrier (endothelial cells and astrocytes) and under inflammatory conditions in microglia/macrophages. GJs connect cells by the docking of two hemichannels, one from each cell with each hemichannel being formed by 6 proteins named connexins (Cx). Unapposed hemichannels (uHC) also can be open on the surface of the cells allowing the release of different intracellular factors to the extracellular space. GJs provide a mechanism of cell-to-cell communication between adjacent cells that enables the direct exchange of intracellular messengers, such as calcium, nucleotides, IP(3), and diverse metabolites, as well as electrical signals that ultimately coordinate tissue homeostasis, proliferation, differentiation, metabolism, cell survival and death. Despite their essential functions in physiological conditions, relatively little is known about the role of GJs and uHC in human diseases, especially within the nervous system. The focus of this review is to summarize recent findings related to the role of GJs and uHC in physiologic and pathologic conditions of the central nervous system.
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Affiliation(s)
- Eliseo A Eugenin
- Department of Pathology, F727, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA.
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Belousov AB. Novel model for the mechanisms of glutamate-dependent excitotoxicity: role of neuronal gap junctions. Brain Res 2012; 1487:123-30. [PMID: 22771704 DOI: 10.1016/j.brainres.2012.05.063] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 05/23/2012] [Accepted: 05/31/2012] [Indexed: 11/16/2022]
Abstract
In the mammalian central nervous system (CNS), coupling of neurons by gap junctions (electrical synapses) increases during early post-natal development, then decreases, but increases in the mature CNS following neuronal injury, such as ischemia, traumatic brain injury and epilepsy. Glutamate-dependent neuronal death also occurs in the CNS during development and neuronal injury, i.e., at the time when neuronal gap junction coupling is increased. Here, we review our recent studies on the regulation of neuronal gap junction coupling by glutamate during development and injury and on the role of gap junctions in neuronal cell death. A novel model of the mechanisms of glutamate-dependent neuronal death is discussed, which includes neuronal gap junction coupling as a critical part of these mechanisms.
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Affiliation(s)
- Andrei B Belousov
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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