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Wang Y, Li Q, Tao B, Angelini M, Ramadoss S, Sun B, Wang P, Krokhaleva Y, Ma F, Gu Y, Espinoza A, Yamauchi K, Pellegrini M, Novitch B, Olcese R, Qu Z, Song Z, Deb A. Fibroblasts in heart scar tissue directly regulate cardiac excitability and arrhythmogenesis. Science 2023; 381:1480-1487. [PMID: 37769108 PMCID: PMC10768850 DOI: 10.1126/science.adh9925] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 08/11/2023] [Indexed: 09/30/2023]
Abstract
After heart injury, dead heart muscle is replaced by scar tissue. Fibroblasts can electrically couple with myocytes, and changes in fibroblast membrane potential can lead to myocyte excitability, which suggests that fibroblast-myocyte coupling in scar tissue may be responsible for arrhythmogenesis. However, the physiologic relevance of electrical coupling of myocytes and fibroblasts and its impact on cardiac excitability in vivo have never been demonstrated. We genetically engineered a mouse that expresses the optogenetic cationic channel ChR2 (H134R) exclusively in cardiac fibroblasts. After myocardial infarction, optical stimulation of scar tissue elicited organ-wide cardiac excitation and induced arrhythmias in these animals. Complementing computational modeling with experimental approaches, we showed that gap junctional and ephaptic coupling, in a synergistic yet functionally redundant manner, excited myocytes coupled to fibroblasts.
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Affiliation(s)
- Yijie Wang
- Division of Cardiology, Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Cardiovascular Theme, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- California Nanosystems Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Qihao Li
- Peng Cheng Laboratory, Shenzhen, Guangdong 518000, China
| | - Bo Tao
- Division of Cardiology, Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Cardiovascular Theme, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- California Nanosystems Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Marina Angelini
- Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Sivakumar Ramadoss
- Division of Cardiology, Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Cardiovascular Theme, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- California Nanosystems Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Baiming Sun
- Division of Cardiology, Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Cardiovascular Theme, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- California Nanosystems Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ping Wang
- Division of Cardiology, Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Cardiovascular Theme, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- California Nanosystems Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Yuliya Krokhaleva
- UCLA Cardiac Arrhythmia Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Feiyang Ma
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Yiqian Gu
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Institute for Quantitative and Computational Biosciences–The Collaboratory, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Alejandro Espinoza
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Institute for Quantitative and Computational Biosciences–The Collaboratory, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ken Yamauchi
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Matteo Pellegrini
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Institute for Quantitative and Computational Biosciences–The Collaboratory, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Bennett Novitch
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Riccardo Olcese
- Department of Anesthesiology and Perioperative Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Zhilin Qu
- Division of Cardiology, Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Zhen Song
- Peng Cheng Laboratory, Shenzhen, Guangdong 518000, China
| | - Arjun Deb
- Division of Cardiology, Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Cardiovascular Theme, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- California Nanosystems Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
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Cibelli A, Stout R, Timmermann A, de Menezes L, Guo P, Maass K, Seifert G, Steinhäuser C, Spray DC, Scemes E. Cx43 carboxyl terminal domain determines AQP4 and Cx30 endfoot organization and blood brain barrier permeability. Sci Rep 2021; 11:24334. [PMID: 34934080 PMCID: PMC8692511 DOI: 10.1038/s41598-021-03694-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/06/2021] [Indexed: 11/08/2022] Open
Abstract
The neurovascular unit (NVU) consists of cells intrinsic to the vessel wall, the endothelial cells and pericytes, and astrocyte endfeet that surround the vessel but are separated from it by basement membrane. Endothelial cells are primarily responsible for creating and maintaining blood-brain-barrier (BBB) tightness, but astrocytes contribute to the barrier through paracrine signaling to the endothelial cells and by forming the glia limitans. Gap junctions (GJs) between astrocyte endfeet are composed of connexin 43 (Cx43) and Cx30, which form plaques between cells. GJ plaques formed of Cx43 do not diffuse laterally in the plasma membrane and thus potentially provide stable organizational features to the endfoot domain, whereas GJ plaques formed of other connexins and of Cx43 lacking a large portion of its cytoplasmic carboxyl terminus are quite mobile. In order to examine the organizational features that immobile GJs impose on the endfoot, we have used super-resolution confocal microscopy to map number and sizes of GJ plaques and aquaporin (AQP)-4 channel clusters in the perivascular endfeet of mice in which astrocyte GJs (Cx30, Cx43) were deleted or the carboxyl terminus of Cx43 was truncated. To determine if BBB integrity was compromised in these transgenic mice, we conducted perfusion studies under elevated hydrostatic pressure using horseradish peroxide as a molecular probe enabling detection of micro-hemorrhages in brain sections. These studies revealed that microhemorrhages were more numerous in mice lacking Cx43 or its carboxyl terminus. In perivascular domains of cerebral vessels, we found that density of Cx43 GJs was higher in the truncation mutant, while GJ size was smaller. Density of perivascular particles formed by AQP4 and its extended isoform AQP4ex was inversely related to the presence of full length Cx43, whereas the ratio of sizes of the particles of the AQP4ex isoform to total AQP4 was directly related to the presence of full length Cx43. Confocal analysis showed that Cx43 and Cx30 were substantially colocalized in astrocyte domains near vasculature of truncation mutant mice. These results showing altered distribution of some astrocyte nexus components (AQP4 and Cx30) in Cx43 null mice and in a truncation mutant, together with leakier cerebral vasculature, support the hypothesis that localization and mobility of gap junction proteins and their binding partners influences organization of astrocyte endfeet which in turn impacts BBB integrity of the NVU.
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Affiliation(s)
- Antonio Cibelli
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Randy Stout
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Aline Timmermann
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Laura de Menezes
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Insitute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Peng Guo
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Cellular Imaging Core Facility, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Karen Maass
- Cardiovascular Research Center, NYU Grossman School of Medicine, New York, NY, USA
| | - Gerald Seifert
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - David C Spray
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA.
| | - Eliana Scemes
- Department of Anatomy and Cell Biology, New York Medical College, Valhalla, NY, 10595, USA.
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Olejnickova V, Kocka M, Kvasilova A, Kolesova H, Dziacky A, Gidor T, Gidor L, Sankova B, Gregorovicova M, Gourdie RG, Sedmera D. Gap Junctional Communication via Connexin43 between Purkinje Fibers and Working Myocytes Explains the Epicardial Activation Pattern in the Postnatal Mouse Left Ventricle. Int J Mol Sci 2021; 22:2475. [PMID: 33804428 PMCID: PMC7957598 DOI: 10.3390/ijms22052475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/19/2021] [Accepted: 02/25/2021] [Indexed: 12/31/2022] Open
Abstract
The mammalian ventricular myocardium forms a functional syncytium due to flow of electrical current mediated in part by gap junctions localized within intercalated disks. The connexin (Cx) subunit of gap junctions have direct and indirect roles in conduction of electrical impulse from the cardiac pacemaker via the cardiac conduction system (CCS) to working myocytes. Cx43 is the dominant isoform in these channels. We have studied the distribution of Cx43 junctions between the CCS and working myocytes in a transgenic mouse model, which had the His-Purkinje portion of the CCS labeled with green fluorescence protein. The highest number of such connections was found in a region about one-third of ventricular length above the apex, and it correlated with the peak proportion of Purkinje fibers (PFs) to the ventricular myocardium. At this location, on the septal surface of the left ventricle, the insulated left bundle branch split into the uninsulated network of PFs that continued to the free wall anteriorly and posteriorly. The second peak of PF abundance was present in the ventricular apex. Epicardial activation maps correspondingly placed the site of the first activation in the apical region, while some hearts presented more highly located breakthrough sites. Taken together, these results increase our understanding of the physiological pattern of ventricular activation and its morphological underpinning through detailed CCS anatomy and distribution of its gap junctional coupling to the working myocardium.
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Affiliation(s)
- Veronika Olejnickova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Institute of Physiology, CAS, 142 20 Prague, Czech Republic
| | - Matej Kocka
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Alena Kvasilova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Hana Kolesova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Institute of Physiology, CAS, 142 20 Prague, Czech Republic
| | - Adam Dziacky
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Department of Pediatric Cardiology, Motol University Hospital, 150 06 Prague, Czech Republic
| | - Tom Gidor
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Lihi Gidor
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Barbora Sankova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
| | - Martina Gregorovicova
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Institute of Physiology, CAS, 142 20 Prague, Czech Republic
| | - Robert G. Gourdie
- Fralin Biomedical Research Institute, Virginia Tech, Roanoke, VA 24016, USA;
| | - David Sedmera
- Institute of Anatomy, First Faculty of Medicine, Charles University, 128 00 Prague, Czech Republic; (V.O.); (M.K.); (A.K.); (H.K.); (A.D.); (T.G.); (L.G.); (B.S.); (M.G.)
- Institute of Physiology, CAS, 142 20 Prague, Czech Republic
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Martins-Marques T, Ribeiro-Rodrigues T, de Jager SC, Zuzarte M, Ferreira C, Cruz P, Reis L, Baptista R, Gonçalves L, Sluijter JP, Girao H. Myocardial infarction affects Cx43 content of extracellular vesicles secreted by cardiomyocytes. Life Sci Alliance 2020; 3:e202000821. [PMID: 33097557 PMCID: PMC7652393 DOI: 10.26508/lsa.202000821] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/12/2022] Open
Abstract
Ischemic heart disease has been associated with an impairment on intercellular communication mediated by both gap junctions and extracellular vesicles. We have previously shown that connexin 43 (Cx43), the main ventricular gap junction protein, assembles into channels at the extracellular vesicle surface, mediating the release of vesicle content into target cells. Here, using a comprehensive strategy that included cell-based approaches, animal models and human patients, we demonstrate that myocardial ischemia impairs the secretion of Cx43 into circulating, intracardiac and cardiomyocyte-derived vesicles. In addition, we show that ubiquitin signals Cx43 release in basal conditions but appears to be dispensable during ischemia, suggesting an interplay between ischemia-induced Cx43 degradation and secretion. Overall, this study constitutes a step forward for the characterization of the signals and molecular players underlying vesicle protein sorting, with strong implications on long-range intercellular communication, paving the way towards the development of innovative diagnostic and therapeutic strategies for cardiovascular disorders.
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Affiliation(s)
- Tania Martins-Marques
- University of Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal
- University of Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
| | - Teresa Ribeiro-Rodrigues
- University of Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal
- University of Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
| | - Saskia C de Jager
- Laboratory of Experimental Cardiology, University Medical Center Utrecht Regenerative Medicine Center, Circulatory Health Laboratory, University Medical Center Utrecht, University Utrecht, Utrecht, The Netherlands
| | - Monica Zuzarte
- University of Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal
- University of Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
| | - Cátia Ferreira
- University of Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
- Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Pedro Cruz
- University of Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
| | - Liliana Reis
- Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
- Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Rui Baptista
- University of Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal
- University of Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
- Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
- Cardiology Department, Centro Hospitalar Entre Douro e Vouga, Santa Maria da Feira, Portugal
| | - Lino Gonçalves
- University of Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal
- University of Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
- Cardiology Department, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
| | - Joost Pg Sluijter
- Laboratory of Experimental Cardiology, University Medical Center Utrecht Regenerative Medicine Center, Circulatory Health Laboratory, University Medical Center Utrecht, University Utrecht, Utrecht, The Netherlands
| | - Henrique Girao
- University of Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, Coimbra, Portugal
- University of Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), Coimbra, Portugal
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Au A, Shao Q, White KK, Lucaciu SA, Esseltine JL, Barr K, Laird DW. Comparative Analysis of Cx31 and Cx43 in Differentiation-Competent Rodent Keratinocytes. Biomolecules 2020; 10:biom10101443. [PMID: 33066499 PMCID: PMC7602205 DOI: 10.3390/biom10101443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/30/2020] [Accepted: 10/08/2020] [Indexed: 12/25/2022] Open
Abstract
When considering connexin expression and regulation, the epidermis of the skin is one of the most complex tissues found in mammals even though it largely contains a single cell type, the keratinocyte. In the rodent epidermis, up to 9 connexin family members have been detected at the mRNA level. Many of these connexins are temporally and spatially regulated in coordination with keratinocyte progenitor cell differentiation and migration from the stratum basale to form the stratum spinosum and stratum granulosum layers before finally forming the stratum corneum. Cx43 is the principal connexin found in basal keratinocytes and to a lesser degree found in keratinocytes that have begun to differentiate where Cx26, Cx30 and Cx31 become prevalent. Here we show that the CRISPR-Cas9 ablation of Cx43 reduces overall gap junction coupling in monolayer cultures of rat epidermal keratinocytes (REKs) and dysregulates the differentiation of REKs when grown in organotypic cultures. Natively found in differentiated keratinocytes, Cx31 readily assembles into gap junctions when expressed in REKs where it can extensively co-assemble into the same gap junctions with co-expressed Cx30. Time-lapse imaging indicated that many Cx31 gap junctions are mobile within the plasma membrane undergoing both fusion and fission events. Finally, the persistence of pre-existing Cx31 gap junctions in the presence of the protein trafficking blocker, brefeldin A, is longer than that found for Cx43 gap junctions indicating that it has a distinctly different life expectancy in REKs. Collectively, this study highlights the importance of Cx43 in rodent keratinocyte differentiation and suggests that Cx31 acquires life-cycle properties that are distinct from Cx43.
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Affiliation(s)
- Akina Au
- Department of Physiology and Pharmacology, The University of Western Ontario, London, ON N6A 5C1, Canada; (A.A.); (S.A.L.)
| | - Qing Shao
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada; (Q.S.); (K.K.W.); (K.B.)
| | - Kyra K. White
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada; (Q.S.); (K.K.W.); (K.B.)
| | - Sergiu A. Lucaciu
- Department of Physiology and Pharmacology, The University of Western Ontario, London, ON N6A 5C1, Canada; (A.A.); (S.A.L.)
| | - Jessica L. Esseltine
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada;
| | - Kevin Barr
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada; (Q.S.); (K.K.W.); (K.B.)
| | - Dale W. Laird
- Department of Physiology and Pharmacology, The University of Western Ontario, London, ON N6A 5C1, Canada; (A.A.); (S.A.L.)
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada; (Q.S.); (K.K.W.); (K.B.)
- Correspondence: ; Tel.: +1-519-661-2111 (ext. 86827)
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6
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Okada M, Fukuyama K, Shiroyama T, Murata M. A Working Hypothesis Regarding Identical Pathomechanisms between Clinical Efficacy and Adverse Reaction of Clozapine via the Activation of Connexin43. Int J Mol Sci 2020; 21:ijms21197019. [PMID: 32987640 PMCID: PMC7583770 DOI: 10.3390/ijms21197019] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 09/04/2020] [Accepted: 09/22/2020] [Indexed: 12/11/2022] Open
Abstract
Clozapine (CLZ) is an approved antipsychotic agent for the medication of treatment-resistant schizophrenia but is also well known as one of the most toxic antipsychotics. Recently, the World Health Organization’s (WHO) global database (VigiBase) reported the relative lethality of severe adverse reactions of CLZ. Agranulocytosis is the most famous adverse CLZ reaction but is of lesser lethality compared with the other adverse drug reactions of CLZ. Unexpectedly, VigiBase indicated that the prevalence and relative lethality of pneumonia, cardiotoxicity, and seizures associated with CLZ were more serious than that of agranulocytosis. Therefore, haematological monitoring in CLZ patients monitoring system provided success in the prevention of lethal adverse events from CLZ-induced agranulocytosis. Hereafter, psychiatrists must amend the CLZ patients monitoring system to protect patients with treatment-resistant schizophrenia from severe adverse CLZ reactions, such as pneumonia, cardiotoxicity, and seizures, according to the clinical evidence and pathophysiology. In this review, we discuss the mechanisms of clinical efficacy and the adverse reactions of CLZ based on the accumulating pharmacodynamic findings of CLZ, including tripartite synaptic transmission, and we propose suggestions for amending the monitoring and medication of adverse CLZ reactions associated with pneumonia, cardiotoxicity, and seizures.
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Affiliation(s)
- Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (T.S.)
- Correspondence: ; Tel.: +81-59-231-5018
| | - Kouji Fukuyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (T.S.)
| | - Takashi Shiroyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (T.S.)
| | - Masahiko Murata
- National Hospital Organization Sakakibara Hospital, 777 Sakakibara, Tsu, Mie 514-1292, Japan;
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Vicario N, Turnaturi R, Spitale FM, Torrisi F, Zappalà A, Gulino R, Pasquinucci L, Chiechio S, Parenti C, Parenti R. Intercellular communication and ion channels in neuropathic pain chronicization. Inflamm Res 2020; 69:841-850. [PMID: 32533221 DOI: 10.1007/s00011-020-01363-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/13/2020] [Accepted: 05/17/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Neuropathic pain is caused by primary lesion or dysfunction of either peripheral or central nervous system. Due to its complex pathogenesis, often related to a number of comorbidities, such as cancer, neurodegenerative and neurovascular diseases, neuropathic pain still represents an unmet clinical need, lacking long-term effective treatment and complex case-by-case approach. AIM AND METHODS We analyzed the recent literature on the role of selective voltage-sensitive sodium, calcium and potassium permeable channels and non-selective gap junctions (GJs) and hemichannels (HCs) in establishing and maintaining chronic neuropathic conditions. We finally focussed our review on the role of extracellular microenvironment modifications induced by resident glial cells and on the recent advances in cell-to-cell and cell-to-extracellular environment communication in chronic neuropathies. CONCLUSION In this review, we provide an update on the current knowledge of neuropathy chronicization processes with a focus on both neuronal and glial ion channels, as well as on channel-mediated intercellular communication.
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Affiliation(s)
- Nunzio Vicario
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Rita Turnaturi
- Section of Medicinal Chemistry, Department of Drug Sciences, University of Catania, Catania, Italy
| | - Federica Maria Spitale
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Filippo Torrisi
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Agata Zappalà
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Rosario Gulino
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy
| | - Lorella Pasquinucci
- Section of Medicinal Chemistry, Department of Drug Sciences, University of Catania, Catania, Italy
| | - Santina Chiechio
- Section of Pharmacology, Department of Drug Sciences, University of Catania, Catania, Italy
- Oasi Research Institute IRCCS, Troina, Italy
| | - Carmela Parenti
- Section of Pharmacology, Department of Drug Sciences, University of Catania, Catania, Italy.
| | - Rosalba Parenti
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, Italy.
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8
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Price GW, Chadjichristos CE, Kavvadas P, Tang SCW, Yiu WH, Green CR, Potter JA, Siamantouras E, Squires PE, Hills CE. Blocking Connexin-43 mediated hemichannel activity protects against early tubular injury in experimental chronic kidney disease. Cell Commun Signal 2020; 18:79. [PMID: 32450899 PMCID: PMC7249671 DOI: 10.1186/s12964-020-00558-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/23/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Tubulointerstitial fibrosis represents the key underlying pathology of Chronic Kidney Disease (CKD), yet treatment options remain limited. In this study, we investigated the role of connexin43 (Cx43) hemichannel-mediated adenosine triphosphate (ATP) release in purinergic-mediated disassembly of adherens and tight junction complexes in early tubular injury. METHODS Human primary proximal tubule epithelial cells (hPTECs) and clonal tubular epithelial cells (HK2) were treated with Transforming Growth Factor Beta1 (TGF-β1) ± apyrase, or ATPγS for 48 h. For inhibitor studies, cells were co-incubated with Cx43 mimetic Peptide 5, or purinergic receptor antagonists Suramin, A438079 or A804598. Immunoblotting, single-cell force spectroscopy and trans-epithelial electrical resistance assessed protein expression, cell-cell adhesion and paracellular permeability. Carboxyfluorescein uptake and biosensing measured hemichannel activity and real-time ATP release, whilst a heterozygous Cx43+/- mouse model with unilateral ureteral obstruction (UUO) assessed the role of Cx43 in vivo. RESULTS Immunohistochemistry of biopsy material from patients with diabetic nephropathy confirmed increased expression of purinergic receptor P2X7. TGF-β1 increased Cx43 mediated hemichannel activity and ATP release in hPTECs and HK2 cells. The cytokine reduced maximum unbinding forces and reduced cell-cell adhesion, which translated to increased paracellular permeability. Changes were reversed when cells were co-incubated with either Peptide 5 or P2-purinoceptor inhibitors. Cx43+/- mice did not exhibit protein changes associated with early tubular injury in a UUO model of fibrosis. CONCLUSION Data suggest that Cx43 mediated ATP release represents an initial trigger in early tubular injury via its actions on the adherens and tight junction complex. Since Cx43 is highly expressed in nephropathy, it represents a novel target for intervention of tubulointerstitial fibrosis in CKD. Video Abstract In proximal tubular epithelial cells (PTECs), tight junction proteins, including zona occuludens-1 (ZO-1), contribute to epithelial integrity, whilst the adherens junction protein epithelial (E)-cadherin (ECAD) maintains cell-cell coupling, facilitating connexin 43 (Cx43) gap junction-mediated intercellular communication (GJIC) and the direct transfer of small molecules and ions between cells. In disease, such as diabetic nephropathy, the pro-fibrotic cytokine transforming growth factor beta1 (TGF-β1) binds to its receptor and recruits SMAD2/3 signalling ahead of changes in gene transcription and up-regulation of Cx43-mediated hemichannels (HC). Uncoupled hemichannels permit the release of adenosine triphosphate (ATP) in to the extracellular space (↑[ATP]e), where ATP binds to the P2X7 purinoreceptor and activates the nucleotide-binding domain and leucine-rich repeat containing (NLR) protein-3 (NLRP3) inflammasome. Inflammation results in epithelial-to-mesenchymal transition (EMT), fibrosis and tubular injury. A major consequence is further loss of ECAD and reduced stickiness between cells, which can be functionally measured as a decrease in the maximum unbinding force needed to uncouple two adherent cells (Fmax). Loss of ECAD feeds forward to further lessen cell-cell coupling exacerbating the switch from GJIC to HC-mediated release of ATP. Reduction in ZO-1 impedes tight junction effectiveness and decreases trans-epithelial resistance (↓TER), resulting in increased paracellular permeability.
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Affiliation(s)
- Gareth W. Price
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Green Lane, Lincoln, UK
| | - Christos E. Chadjichristos
- National Institutes for Health and Medical Research Unite Mixte de Recherche S1155, Batiment Recherche, Tenon Hospital, 4 rue de la Chine, 75020 Paris, France
| | - Panagiotis Kavvadas
- National Institutes for Health and Medical Research Unite Mixte de Recherche S1155, Batiment Recherche, Tenon Hospital, 4 rue de la Chine, 75020 Paris, France
| | - Sydney C. W. Tang
- Division of Nephrology, Department of Medicine, The University of Hong Kong, Hong Kong, Hong Kong
| | - Wai Han Yiu
- Division of Nephrology, Department of Medicine, The University of Hong Kong, Hong Kong, Hong Kong
| | - Colin R. Green
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Joe A. Potter
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Green Lane, Lincoln, UK
| | - Eleftherios Siamantouras
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Green Lane, Lincoln, UK
| | - Paul E. Squires
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Green Lane, Lincoln, UK
| | - Claire E. Hills
- Joseph Banks Laboratories, School of Life Sciences, University of Lincoln, Green Lane, Lincoln, UK
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Diez ER, Sánchez JA, Prado NJ, Ponce Zumino AZ, García-Dorado D, Miatello RM, Rodríguez-Sinovas A. Ischemic Postconditioning Reduces Reperfusion Arrhythmias by Adenosine Receptors and Protein Kinase C Activation but Is Independent of K ATP Channels or Connexin 43. Int J Mol Sci 2019; 20:ijms20235927. [PMID: 31775376 PMCID: PMC6928819 DOI: 10.3390/ijms20235927] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 12/18/2022] Open
Abstract
Ischemic postconditioning (IPoC) reduces reperfusion arrhythmias but the antiarrhythmic mechanisms remain unknown. The aim of this study was to analyze IPoC electrophysiological effects and the role played by adenosine A1, A2A and A3 receptors, protein kinase C, ATP-dependent potassium (KATP) channels, and connexin 43. IPoC reduced reperfusion arrhythmias (mainly sustained ventricular fibrillation) in isolated rat hearts, an effect associated with a transient delay in epicardial electrical activation, and with action potential shortening. Electrical impedance measurements and Lucifer-Yellow diffusion assays agreed with such activation delay. However, this delay persisted during IPoC in isolated mouse hearts in which connexin 43 was replaced by connexin 32 and in mice with conditional deletion of connexin 43. Adenosine A1, A2A and A3 receptor blockade antagonized the antiarrhythmic effect of IPoC and the associated action potential shortening, whereas exogenous adenosine reduced reperfusion arrhythmias and shortened action potential duration. Protein kinase C inhibition by chelerythrine abolished the protective effect of IPoC but did not modify the effects on action potential duration. On the other hand, glibenclamide, a KATP inhibitor, antagonized the action potential shortening but did not interfere with the antiarrhythmic effect. The antiarrhythmic mechanisms of IPoC involve adenosine receptor activation and are associated with action potential shortening. However, this action potential shortening is not essential for protection, as it persisted during protein kinase C inhibition, a maneuver that abolished IPoC protection. Furthermore, glibenclamide induced the opposite effects. In addition, IPoC delays electrical activation and electrical impedance recovery during reperfusion, but these effects are independent of connexin 43.
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Affiliation(s)
- Emiliano Raúl Diez
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina; (E.R.D.); (N.J.P.); (A.Z.P.Z.); (R.M.M.)
- Institute of Medical and Experimental Biology of Cuyo, CONICET, Mendoza 5500, Argentina
| | - Jose Antonio Sánchez
- Cardiovascular Diseases Research Group, Department of Cardiology, Vall d’Hebron University Hospital and Research Institute, Universitat Autònoma de Barcelona, Departament de Medicina, Pg. Vall d’Hebron 119-129, 08035 Barcelona, Spain; (J.A.S.); (D.G.-D.)
- Centro de Investigación Biomédica en Red sobre Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - Natalia Jorgelina Prado
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina; (E.R.D.); (N.J.P.); (A.Z.P.Z.); (R.M.M.)
- Institute of Medical and Experimental Biology of Cuyo, CONICET, Mendoza 5500, Argentina
| | - Amira Zulma Ponce Zumino
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina; (E.R.D.); (N.J.P.); (A.Z.P.Z.); (R.M.M.)
- Institute of Medical and Experimental Biology of Cuyo, CONICET, Mendoza 5500, Argentina
| | - David García-Dorado
- Cardiovascular Diseases Research Group, Department of Cardiology, Vall d’Hebron University Hospital and Research Institute, Universitat Autònoma de Barcelona, Departament de Medicina, Pg. Vall d’Hebron 119-129, 08035 Barcelona, Spain; (J.A.S.); (D.G.-D.)
- Centro de Investigación Biomédica en Red sobre Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
| | - Roberto Miguel Miatello
- Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina; (E.R.D.); (N.J.P.); (A.Z.P.Z.); (R.M.M.)
- Institute of Medical and Experimental Biology of Cuyo, CONICET, Mendoza 5500, Argentina
| | - Antonio Rodríguez-Sinovas
- Cardiovascular Diseases Research Group, Department of Cardiology, Vall d’Hebron University Hospital and Research Institute, Universitat Autònoma de Barcelona, Departament de Medicina, Pg. Vall d’Hebron 119-129, 08035 Barcelona, Spain; (J.A.S.); (D.G.-D.)
- Centro de Investigación Biomédica en Red sobre Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-93-4894184; Fax: +34-93-4894032
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10
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Ek-Vitorín JF, Pontifex TK, Burt JM. Cx43 Channel Gating and Permeation: Multiple Phosphorylation-Dependent Roles of the Carboxyl Terminus. Int J Mol Sci 2018; 19:E1659. [PMID: 29867029 PMCID: PMC6032060 DOI: 10.3390/ijms19061659] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/22/2018] [Accepted: 05/31/2018] [Indexed: 12/18/2022] Open
Abstract
Connexin 43 (Cx43), a gap junction protein seemingly fit to support cardiac impulse propagation and synchronic contraction, is phosphorylated in normoxia by casein kinase 1 (CK1). However, during cardiac ischemia or pressure overload hypertrophy, this phosphorylation fades, Cx43 abundance decreases at intercalated disks and increases at myocytes' lateral borders, and the risk of arrhythmia rises. Studies in wild-type and transgenic mice indicate that enhanced CK1-phosphorylation of Cx43 protects from arrhythmia, while dephosphorylation precedes arrhythmia vulnerability. The mechanistic bases of these Cx43 (de)phosphoform-linked cardiac phenotypes are unknown. We used patch-clamp and dye injection techniques to study the channel function (gating, permeability) of Cx43 mutants wherein CK1-targeted serines were replaced by aspartate (Cx43-CK1-D) or alanine (Cx43-CK1-A) to emulate phosphorylation and dephosphorylation, respectively. Cx43-CK1-D, but not Cx43-CK1-A, displayed high Voltage-sensitivity and variable permselectivity. Both mutants showed multiple channel open states with overall increased conductivity, resistance to acidification-induced junctional uncoupling, and hemichannel openings in normal external calcium. Modest differences in the mutant channels' function and regulation imply the involvement of dissimilar structural conformations of the interacting domains of Cx43 in electrical and chemical gating that may contribute to the divergent phenotypes of CK1-(de)phospho-mimicking Cx43 transgenic mice and that may bear significance in arrhythmogenesis.
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Affiliation(s)
- José F Ek-Vitorín
- Department of Physiology, University of Arizona, P.O. Box 245051, Tucson, AZ 85724, USA.
| | - Tasha K Pontifex
- Department of Physiology, University of Arizona, P.O. Box 245051, Tucson, AZ 85724, USA.
| | - Janis M Burt
- Department of Physiology, University of Arizona, P.O. Box 245051, Tucson, AZ 85724, USA.
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Hollenbach J, Jung K, Noelke J, Gasse H, Pfarrer C, Koy M, Brehm R. Loss of connexin43 in murine Sertoli cells and its effect on blood-testis barrier formation and dynamics. PLoS One 2018; 13:e0198100. [PMID: 29856785 PMCID: PMC5983412 DOI: 10.1371/journal.pone.0198100] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 05/14/2018] [Indexed: 12/11/2022] Open
Abstract
Connexin43 (Cx43) is the predominant testicular gap junction protein and in cases of impaired spermatogenesis, Cx43 expression has been shown to be altered in several mammals. Amongst other functions, Cx43 is supposed to regulate junction formation of the blood-testis barrier (BTB). The aim of the present study was to investigate the expression pattern of different tight junction (TJ) proteins of the murine BTB using SC-specific Cx43 knockout mice (SCCx43KO). Adult homozygous male SCCx43KO mice (SCCx43KO-/-) predominantly show an arrest of spermatogenesis and SC-only tubules that might have been caused by an altered BTB assembly, composition or regulation. TJ molecules claudin-3, -5 and -11 were examined in adult wild type (WT) and SCCx43KO-/- mice using immunohistochemistry (IHC) and quantitative real-time PCR (qRT-PCR). In this context, investigation of single tubules with residual spermatogenesis in SCCx43KO-/- mice was particularly interesting to identify a potential Cx43-independent influence of germ cells (GC) on BTB composition and dynamics. In tubules without residual spermatogenesis, a diffuse cytoplasmic distribution pattern for claudin-11 protein could be demonstrated in mutant mice. Nevertheless, claudin-11 seems to form functional TJ. Claudin-3 and -5 could not be detected immunohistochemically in the seminiferous epithelium of those tubules. Correspondingly, claudin-3 and -5 mRNA expression was decreased, providing evidence of generally impaired BTB dynamics in adult KO mice. Observations of tubules with residual spermatogenesis suggested a Cx43-independent regulation of TJ proteins by GC populations. To determine initial BTB formation in peripubertal SCCx43KO-/- mice, immunohistochemical staining and qRT-PCR of claudin-11 were carried out in adolescent SCCx43KO-/- and WT mice. Additionally, BTB integrity was functionally analysed using a hypertonic glucose fixative. These analyses revealed that SCCx43KO-/- mice formed an intact BTB during puberty in the same time period as WT mice, which however seemed to be accelerated.
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Affiliation(s)
- Julia Hollenbach
- Institute for Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Klaus Jung
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Joanna Noelke
- Institute for Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Hagen Gasse
- Institute for Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Christiane Pfarrer
- Institute for Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Mirja Koy
- Institute for Immunology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Ralph Brehm
- Institute for Anatomy, University of Veterinary Medicine Hannover, Hannover, Germany
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12
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Cheng X, Hou Z, Sun J, Huang Y, Wang L, Zhou Z, Zhou LH, Cai Y. Protective effects of Tongxinluo on cerebral ischemia/reperfusion injury related to Connexin 43/Calpain II/Bax/Caspase-3 pathway in rat. J Ethnopharmacol 2017; 198:148-157. [PMID: 28065778 DOI: 10.1016/j.jep.2017.01.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 12/22/2016] [Accepted: 01/04/2017] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Tongxinluo (TXL) is a multifunctional traditional Chinese medicine and has been widely used in the treatment of cardiovascular and cerebrovascular diseases. Numerous studies demonstrate that TXL is a novel neuroprotective drug, however, the mechanisms are largely unknown. AIM OF THE STUDY we aimed to demonstrate the protective effect of TXL on cerebral ischemia/reperfusion (I/R) injury and provide the evidence for the involvement of Connexin 43/Calpain II/ Bax/Caspase-3 pathway in TXL-mediated neuroprotection. METHODS Focal cerebral I/R injury were induced by transient middle cerebral artery occlusion (MCAO, for 90min) in adult male Sprague-Dawley rats. We estimated the effects of TXL on I/R injury including neurological deficit assessment and cerebral infarct volume measurement via TTC staining, and detected the protein expression of Connexin 43 (Cx43) by western blot. Furthermore, after the intracerebroventricular injection of carbenoxolone (CBX, the inhibitor of Cx43) at 30min before MCAO surgery, Calpain II, Bax and cleaved Caspased-3 immunoreactivity in ischemic penumbra region was detected by immunofluorescent staining, and cell apoptosis was detected by TUNEL staining. RESULTS TXL treatment greatly improved neurological deficit and reduced the infarction volume compared to MCAO with buffer treatment (P<0.05), and TXL pre-post treatment showed better results than TXL pre-treatment. TXL pre-post treatment significantly up-regulated Cx43 protein expression at 3d, 7d and 14d post-injury compared to MCAO with buffer treatment (P<0.05). Meanwhile, the immunoreactivity of Calpain II, Bax and cleaved Caspase-3 in ischemic penumbra region was obviously decreased by TXL pre-post treatment compared to MCAO group (P<0.05). However, with the treatment of the Cx43 inhibitor, CBX, the down-regulated effect of TXL on Calpain II, Bax and cleaved Caspase-3 immunoreactivity was abolished (P<0.05). Moreover, the protective effect of TXL against neuron apoptosis in penumbra region was conteracted by CBX (P<0.05). CONCLUSIONS TXL could effectively protect against I/R injury and reduced cell death via Cx43/Calpain II/Bax/Caspase-3 pathway, which contribute to I/R injury prevention and therapy.
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Affiliation(s)
- Xiao Cheng
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou 510120, China; The Second Institute of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510120, China.
| | - Zijun Hou
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou 510120, China; The Second Institute of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510120, China; Medical Experimental Center, Nanyang Institute of Technology, Nanyang 473004, P.R. China.
| | - Jingbo Sun
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou 510120, China; The Second Institute of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510120, China.
| | - Yan Huang
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou 510120, China; The Second Institute of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510120, China.
| | - Lixin Wang
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou 510120, China; The Second Institute of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510120, China.
| | - Ziyi Zhou
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou 510120, China; The Second Institute of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510120, China.
| | - Li-Hua Zhou
- Department of Anatomy, Zhong Shan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China.
| | - Yefeng Cai
- Department of Neurology, Guangdong Provincial Hospital of Traditional Chinese Medicine, Guangzhou 510120, China; The Second Institute of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510120, China.
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13
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Choi SR, Roh DH, Yoon SY, Kwon SG, Choi HS, Han HJ, Beitz AJ, Lee JH. Astrocyte sigma-1 receptors modulate connexin 43 expression leading to the induction of below-level mechanical allodynia in spinal cord injured mice. Neuropharmacology 2016; 111:34-46. [PMID: 27567941 DOI: 10.1016/j.neuropharm.2016.08.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 08/21/2016] [Accepted: 08/23/2016] [Indexed: 01/13/2023]
Abstract
We have previously shown using a spinal cord injury (SCI) model that gap junctions contribute to the early spread of astrocyte activation in the lumbar spinal cord and that this astrocyte communication plays critical role in the induction of central neuropathic pain. Sigma-1 receptors (Sig-1Rs) have been implicated in spinal astrocyte activation and the development of peripheral neuropathic pain, yet their contribution to central neuropathic pain remains unknown. Thus, we investigated whether SCI upregulates spinal Sig-1Rs, which in turn increase the expression of the astrocytic gap junction protein, connexin 43 (Cx43) leading to the induction of central neuropathic pain. A thoracic spinal cord hemisection significantly increased both astrocyte activation and Cx43 expression in lumbar dorsal horn. Sig-1Rs were also increased in lumbar dorsal horn astrocytes, but not neurons or microglia. Intrathecal injection of an astrocyte metabolic inhibitor (fluorocitrate); a gap junction/hemichannel blocker (carbenoxolone); or a Cx43 mimetic peptide (43Gap26) significantly reduced SCI-induced bilateral below-level mechanical allodynia. Blockade of Sig-1Rs with BD1047 during the induction phase of pain significantly suppressed the SCI-induced development of mechanical allodynia, astrocyte activation, increased expression of Cx43 in both total and membrane levels, and increased association of Cx43 with Sig-1R. However, SCI did not change the expression of oligodendrocyte (Cx32) or neuronal (Cx36) gap junction proteins. These findings demonstrate that SCI activates astrocyte Sig-1Rs leading to increases in the expression of the gap junction protein, Cx43 and astrocyte activation in the lumbar dorsal horn, and ultimately contribute to the induction of bilateral below-level mechanical allodynia.
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Affiliation(s)
- Sheu-Ran Choi
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea
| | - Dae-Hyun Roh
- Department of Maxillofacial Tissue Regeneration and Research Center for Tooth and Periodontal Tissue Regeneration, School of Dentistry, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Seo-Yeon Yoon
- Pain Cognitive Function Research Center, Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Soon-Gu Kwon
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea
| | - Hoon-Seong Choi
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea
| | - Ho-Jae Han
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea
| | - Alvin J Beitz
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN 55108, USA
| | - Jang-Hern Lee
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 08826, Republic of Korea.
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Abstract
Human labour is an inflammatory event, physiologically driven by an interaction between hormonal and mechanical factors and pathologically associated with infection, bleeding and excessive uterine stretch. The initiation and communicators of inflammation is still not completely understood; however, a key role for cytokines has been implicated. We summarise the current understanding of the nature and role of cytokines, chemokines and hormones and their involvement in signalling within the myometrium particularly during labour.
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Affiliation(s)
- S P Sivarajasingam
- Department of Surgery and CancerImperial College London, Chelsea and Westminster Hospital, London, UK
| | - N Imami
- Department of MedicineImperial College London, London, UK
| | - M R Johnson
- Department of Surgery and CancerImperial College London, Chelsea and Westminster Hospital, London, UK
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15
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Kay CWP, Ursu D, Sher E, King AE. The role of Cx36 and Cx43 in 4-aminopyridine-induced rhythmic activity in the spinal nociceptive dorsal horn: an electrophysiological study in vitro. Physiol Rep 2016; 4:e12852. [PMID: 27462070 PMCID: PMC4962069 DOI: 10.14814/phy2.12852] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 06/10/2016] [Accepted: 06/13/2016] [Indexed: 01/09/2023] Open
Abstract
Connexin (Cx) proteins and gap junctions support the formation of neuronal and glial syncytia that are linked to different forms of rhythmic firing and oscillatory activity in the CNS. In this study, quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to profile developmental expression of two specific Cx proteins, namely glial Cx43 and neuronal Cx36, in postnatal lumbar spinal cord aged 4, 7, and 14 days. Extracellular electrophysiology was used to determine the contribution of Cx36 and Cx43 to a previously described form of 4-aminopyridine (4-AP)-induced 4-12 Hz rhythmic activity within substantia gelatinosa (SG) of rat neonatal dorsal horn (DH) in vitro. The involvement of Cx36 and Cx43 was probed pharmacologically using quinine, a specific uncoupler of Cx36 and the mimetic peptide blocker Gap 26 which targets Cx43. After establishment of 4-12 Hz rhythmic activity by 4-AP (25 μmol/L), coapplication of quinine (250 μmol/L) reduced 4-AP-induced 4-12 Hz rhythmic activity (P < 0.05). Preincubation of spinal cord slices with Gap 26 (100 μmol/L), compromised the level of 4-AP-induced 4-12 Hz rhythmic activity in comparison with control slices preincubated in ACSF alone (P < 0.05). Conversely, the nonselective gap junction "opener" trimethylamine (TMA) enhanced 4-12 Hz rhythmic behavior (P < 0.05), further supporting a role for Cx proteins and gap junctions. These data have defined a physiological role for Cx36 and Cx43 in rhythmic firing in SG, a key nociceptive processing area of DH. The significance of these data in the context of pain and Cx proteins as a future analgesic drug target requires further study.
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Affiliation(s)
- Christopher W P Kay
- School of Biomedical Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Daniel Ursu
- Eli Lilly & Co., Lilly Research Centre Erl Wood Manor, Windlesham, Surrey, GU20 6PH, United Kingdom
| | - Emanuele Sher
- Eli Lilly & Co., Lilly Research Centre Erl Wood Manor, Windlesham, Surrey, GU20 6PH, United Kingdom
| | - Anne E King
- School of Biomedical Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
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Longchamp A, Allagnat F, Alonso F, Kuppler C, Dubuis C, Ozaki CK, Mitchell JR, Berceli S, Corpataux JM, Déglise S, Haefliger JA. Connexin43 Inhibition Prevents Human Vein Grafts Intimal Hyperplasia. PLoS One 2015; 10:e0138847. [PMID: 26398895 PMCID: PMC4580578 DOI: 10.1371/journal.pone.0138847] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/04/2015] [Indexed: 12/12/2022] Open
Abstract
Venous bypass grafts often fail following arterial implantation due to excessive smooth muscle cells (VSMC) proliferation and consequent intimal hyperplasia (IH). Intercellular communication mediated by Connexins (Cx) regulates differentiation, growth and proliferation in various cell types. Microarray analysis of vein grafts in a model of bilateral rabbit jugular vein graft revealed Cx43 as an early upregulated gene. Additional experiments conducted using an ex-vivo human saphenous veins perfusion system (EVPS) confirmed that Cx43 was rapidly increased in human veins subjected ex-vivo to arterial hemodynamics. Cx43 knock-down by RNA interference, or adenoviral-mediated overexpression, respectively inhibited or stimulated the proliferation of primary human VSMC in vitro. Furthermore, Cx blockade with carbenoxolone or the specific Cx43 inhibitory peptide 43gap26 prevented the burst in myointimal proliferation and IH formation in human saphenous veins. Our data demonstrated that Cx43 controls proliferation and the formation of IH after arterial engraftment.
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Affiliation(s)
- Alban Longchamp
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
- Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Florent Allagnat
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Florian Alonso
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Christopher Kuppler
- Malcom Randall Veterans Affairs Medical Center and the Division of Vascular and Endovascular Surgery, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Céline Dubuis
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Charles-Keith Ozaki
- Department of Surgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - James R. Mitchell
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Scott Berceli
- Malcom Randall Veterans Affairs Medical Center and the Division of Vascular and Endovascular Surgery, University of Florida College of Medicine, Gainesville, Florida, United States of America
| | - Jean-Marc Corpataux
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Sébastien Déglise
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
| | - Jacques-Antoine Haefliger
- Department of Vascular Surgery, Centre Hospitalier Universitaire Vaudois, Laboratory of Experimental Medicine, Lausanne, Switzerland
- * E-mail:
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Abstract
Bone adaptation to changes in mechanical stimuli occurs by adjusting bone formation and resorption by osteoblasts and osteoclasts, to maintain optimal bone mass. Osteocytes coordinate the actions of these cells on the bone surface by sensing mechanical forces and producing cytokines that increase or prevent osteoblast and osteoclast differentiation and function. Channels formed by connexins (Cxs) and, in particular, connexin 43 (Cx43) in osteoblasts and osteocytes are central part of this mechanism to control bone mass. Cx43 hemichannels are opened by fluid flow and mediate the anti-apoptotic effect of mechanical stimulation in vitro, suggesting that Cx43 participates in mechanotransduction. However, mice lacking Cx43 in osteoblasts and/or osteocytes show an increased anabolic response to loading and decreased catabolic response to unloading. This evidence suggests that Cx43 channels expressed in osteoblastic cells are not required for the response to mechanical stimulation, but mediate the consequence of lack thereof. The molecular basis of these unexpected responses to mechanical stimulation is currently under investigation.
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Affiliation(s)
- Lilian I Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, and Roudebush Veterans Administration Medical Center, 635 Barnhill Drive, MS-5035, Indianapolis, IN, 46202, USA,
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18
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George SA, Sciuto KJ, Lin J, Salama ME, Keener JP, Gourdie RG, Poelzing S. Extracellular sodium and potassium levels modulate cardiac conduction in mice heterozygous null for the Connexin43 gene. Pflugers Arch 2015; 467:2287-97. [PMID: 25771952 DOI: 10.1007/s00424-015-1698-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 02/18/2015] [Accepted: 03/02/2015] [Indexed: 11/27/2022]
Abstract
UNLABELLED Several studies have disagreed on measurements of cardiac conduction velocity (CV) in mice with a heterozygous knockout of the connexin gene Gja1--a mutation that reduces the gap junction (GJ) protein, Connexin43 (Cx43), by 50 %. We noted that perfusate ionic composition varied between studies and hypothesized that extracellular ionic concentration modulates CV dependence on GJs. CV was measured by optically mapping wild-type (WT) and heterozygous null (HZ) hearts serially perfused with solutions previously associated with no change (Solution 1) or CV slowing (Solution 2). In WT hearts, CV was similar for Solutions 1 and 2. However, consistent with the hypothesis, Solution 2 in HZ hearts slowed transverse CV (CVT) relative to Solution 1. Previously, we showed CV slowing in a manner consistent with ephaptic conduction correlated with increased perinexal inter-membrane width (W P) at GJ edges. Thus, W P was measured following perfusion with systematically adjusted [Na(+)]o and [K(+)]o in Solutions 1 and 2. A wider W P was associated with reduced CVT in WT and HZ hearts, with the greatest effect in HZ hearts. Increasing [Na(+)]o increased CVT only in HZ hearts. Increasing [K(+)]o slowed CVT in both WT and HZ hearts with large W P but only in HZ hearts with narrow W P. CONCLUSION When perinexi are wide, decreasing excitability by modulating [Na(+)]o and [K(+)]o increases CV sensitivity to reduced Cx43. By contrast, CV is less sensitive to Cx43 and ion composition when perinexi are narrow. These results are consistent with cardiac conduction dependence on both GJ and non-GJ (ephaptic) mechanisms.
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Affiliation(s)
- Sharon A George
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
- Center for Heart and Regenerative Medicine, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA, 24016, USA
| | - Katherine J Sciuto
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, USA
| | - Joyce Lin
- Department of Mathematics, California Polytechnic State University, San Luis Obispo, CA, USA
| | - Mohamed E Salama
- Department of Pathology, University of Utah and ARUP Reference Lab Institute of Research, Salt Lake City, UT, USA
| | - James P Keener
- Department of Mathematics, University of Utah, Salt Lake City, UT, USA
| | - Robert G Gourdie
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
- Center for Heart and Regenerative Medicine, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA, 24016, USA
| | - Steven Poelzing
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
- Center for Heart and Regenerative Medicine, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA, 24016, USA.
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19
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Sinner MF, Tucker NR, Lunetta KL, Ozaki K, Smith JG, Trompet S, Bis JC, Lin H, Chung MK, Nielsen JB, Lubitz SA, Krijthe BP, Magnani JW, Ye J, Gollob MH, Tsunoda T, Müller-Nurasyid M, Lichtner P, Peters A, Dolmatova E, Kubo M, Smith JD, Psaty BM, Smith NL, Jukema JW, Chasman DI, Albert CM, Ebana Y, Furukawa T, MacFarlane P, Harris TB, Darbar D, Dörr M, Holst AG, Svendsen JH, Hofman A, Uitterlinden AG, Gudnason V, Isobe M, Malik R, Dichgans M, Rosand J, Van Wagoner DR, Benjamin EJ, Milan DJ, Melander O, Heckbert SR, Ford I, Liu Y, Barnard J, Olesen MS, Stricker BH, Tanaka T, Kääb S, Ellinor PT. Integrating genetic, transcriptional, and functional analyses to identify 5 novel genes for atrial fibrillation. Circulation 2014; 130:1225-35. [PMID: 25124494 PMCID: PMC4190011 DOI: 10.1161/circulationaha.114.009892] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) affects >30 million individuals worldwide and is associated with an increased risk of stroke, heart failure, and death. AF is highly heritable, yet the genetic basis for the arrhythmia remains incompletely understood. METHODS AND RESULTS To identify new AF-related genes, we used a multifaceted approach, combining large-scale genotyping in 2 ethnically distinct populations, cis-eQTL (expression quantitative trait loci) mapping, and functional validation. Four novel loci were identified in individuals of European descent near the genes NEURL (rs12415501; relative risk [RR]=1.18; 95% confidence interval [CI], 1.13-1.23; P=6.5×10(-16)), GJA1 (rs13216675; RR=1.10; 95% CI, 1.06-1.14; P=2.2×10(-8)), TBX5 (rs10507248; RR=1.12; 95% CI, 1.08-1.16; P=5.7×10(-11)), and CAND2 (rs4642101; RR=1.10; 95% CI, 1.06-1.14; P=9.8×10(-9)). In Japanese, novel loci were identified near NEURL (rs6584555; RR=1.32; 95% CI, 1.26-1.39; P=2.0×10(-25)) and CUX2 (rs6490029; RR=1.12; 95% CI, 1.08-1.16; P=3.9×10(-9)). The top single-nucleotide polymorphisms or their proxies were identified as cis-eQTLs for the genes CAND2 (P=2.6×10(-19)), GJA1 (P=2.66×10(-6)), and TBX5 (P=1.36×10(-5)). Knockdown of the zebrafish orthologs of NEURL and CAND2 resulted in prolongation of the atrial action potential duration (17% and 45%, respectively). CONCLUSIONS We have identified 5 novel loci for AF. Our results expand the diversity of genetic pathways implicated in AF and provide novel molecular targets for future biological and pharmacological investigation.
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Affiliation(s)
- Moritz F. Sinner
- Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians-University, Munich, Germany
| | - Nathan R. Tucker
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA
| | - Kathryn L. Lunetta
- Department of Biostatistics, Boston University School of Public Health, Boston, MA
- National Heart, Lung and Blood Institute’s and Boston University's Framingham Heart Study, Framingham, MA
| | - Kouichi Ozaki
- Laboratory for Cardiovascular Diseases, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - J. Gustav Smith
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA
- Department of Cardiology, Lund University, Lund, Sweden
| | - Stella Trompet
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Joshua C. Bis
- Cardiovascular Health Research Unit, University of Washington, Seattle, WA
- Department of Medicine, University of Washington, Seattle, WA
| | - Honghuang Lin
- National Heart, Lung and Blood Institute’s and Boston University's Framingham Heart Study, Framingham, MA
- Computational Biomedicine Section, Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Mina K. Chung
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Jonas B. Nielsen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark
- Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Steven A. Lubitz
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA
- Cardiac Arrhythmia Service, Masschusetts General Hospital, Boston, MA
| | - Bouwe P. Krijthe
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Netherlands Consortium for Healthy Aging (NCHA), Netherlands
| | - Jared W. Magnani
- Cardiology Section, Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Jiangchuan Ye
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA
| | - Michael H. Gollob
- Arrhythmia Research Laboratory, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
| | - Tatsuhiko Tsunoda
- Laboratory for Medical Science Mathematics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Martina Müller-Nurasyid
- Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians-University, Munich, Germany
- Institute of Genetic Epidemiology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Medical Informatics, Biometry and Epidemiology, Ludwig-Maximilians-University, Munich, Germany
| | - Peter Lichtner
- Institute of Human Genetics, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
| | - Annette Peters
- Deutsches Zentrum für Herz- Kreislaufforschung e.V. (DZHK), partner site Munich Heart Alliance, Munich, Germany
- Institute of Epidemiology II, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany
| | - Elena Dolmatova
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA
| | - Michiaki Kubo
- Laboratory for Genotyping Development, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Jonathan D. Smith
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH
- Department of Cellular & Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Bruce M. Psaty
- Cardiovascular Health Research Unit, University of Washington, Seattle, WA
- Group Health Research Institute, Group Helath Cooperative, Seattle, WA
- Department of Epidemiology, University of Washington, Seattle, WA
- Department of Health Services, University of Washington, Seattle, WA
| | - Nicholas L. Smith
- Cardiovascular Health Research Unit, University of Washington, Seattle, WA
- Group Health Research Institute, Group Helath Cooperative, Seattle, WA
- Department of Epidemiology, University of Washington, Seattle, WA
- Epidemiologic Research and Information Center of the Department of Veterans Affairs Office of Research and Development, Seattle, WA
| | - J. Wouter Jukema
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
- Interuniversity Cardiology Institute of the Netherlands, Utrecht, The Netherlands
| | - Daniel I. Chasman
- Division of Preventive Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Christine M. Albert
- Division of Preventive Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Division of Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Yusuke Ebana
- Department of Bio-Informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsushi Furukawa
- Department of Bio-Informational Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Peter MacFarlane
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK
| | - Tamara B. Harris
- Laboratory of Epidemiology, Demography, and Biometry, Intramural Research Program, National Institute on Aging, National Institutes of Health, Bethesda, MD
| | - Dawood Darbar
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN
| | - Marcus Dörr
- Department of Internal Medicine B, Ernst Moritz Arndt University Greifswald, Greifswald, Germany
| | - Anders G. Holst
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark
- Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jesper H. Svendsen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark
- Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Albert Hofman
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Netherlands Consortium for Healthy Aging (NCHA), Netherlands
| | - Andre G. Uitterlinden
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Netherlands Consortium for Healthy Aging (NCHA), Netherlands
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Vilmundur Gudnason
- Icelandic Heart Association Research Institute, Kopavogur, Iceland
- University of Iceland, Reykjavik, Iceland
| | - Mitsuaki Isobe
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Japan
| | - Rainer Malik
- Institute for Stroke and Dementia Research, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany
| | - Martin Dichgans
- Institute for Stroke and Dementia Research, University Hospital Munich, Ludwig-Maximilians-University, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Jonathan Rosand
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA
- Department of Neurology, Massachusetts General Hospital, Boston, MA
- Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA
| | - David R. Van Wagoner
- Department of Cardiovascular Medicine, Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH
- Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | | | - Emelia J. Benjamin
- National Heart, Lung and Blood Institute’s and Boston University's Framingham Heart Study, Framingham, MA
- Cardiology Section, Department of Medicine, Boston University School of Medicine, Boston, MA
- Department of Epidemiology, Boston University School of Public Health, Boston, MA
- Preventive Medicine Section, Department of Medicine, Boston University School of Medicine, Boston, MA
| | - David J. Milan
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA
- Cardiac Arrhythmia Service, Masschusetts General Hospital, Boston, MA
| | - Olle Melander
- Department of Clinical Sciences, Lund University, Malmo, Sweden
| | - Susan R. Heckbert
- Cardiovascular Health Research Unit, University of Washington, Seattle, WA
- Group Health Research Institute, Group Helath Cooperative, Seattle, WA
- Department of Epidemiology, University of Washington, Seattle, WA
| | - Ian Ford
- Robertson Centre for Biostatistics, University of Glasgow, Glasgow, UK
| | - Yongmei Liu
- Department of Epidemiology & Prevention, Public Health Sciences, Wake Forest School of Medicine, Winston Salem, NC
| | - John Barnard
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Morten S. Olesen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark
- Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Bruno H.C. Stricker
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Netherlands Consortium for Healthy Aging (NCHA), Netherlands
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
- Inspectorate for Health Care, the Hague, The Netherlands
- Department of Medical Informatics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Toshihiro Tanaka
- Laboratory for Cardiovascular Diseases, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Department of Human Genetics and Disease Diversity, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Stefan Kääb
- Department of Medicine I, University Hospital Munich, Campus Grosshadern, Ludwig-Maximilians-University, Munich, Germany
- Deutsches Zentrum für Herz- Kreislaufforschung e.V. (DZHK), partner site Munich Heart Alliance, Munich, Germany
| | - Patrick T. Ellinor
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA
- Cardiac Arrhythmia Service, Masschusetts General Hospital, Boston, MA
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA
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20
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Palacios-Prado N, Chapuis S, Panjkovich A, Fregeac J, Nagy JI, Bukauskas FF. Molecular determinants of magnesium-dependent synaptic plasticity at electrical synapses formed by connexin36. Nat Commun 2014; 5:4667. [PMID: 25135336 PMCID: PMC4142521 DOI: 10.1038/ncomms5667] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 07/11/2014] [Indexed: 01/28/2023] Open
Abstract
Neuronal gap junction (GJ) channels composed of connexin36 (Cx36) play an important role in neuronal synchronization and network dynamics. Here we show that Cx36-containing electrical synapses between inhibitory neurons of the thalamic reticular nucleus are bidirectionally modulated by changes in intracellular free magnesium concentration ([Mg(2+)]i). Chimeragenesis demonstrates that the first extracellular loop of Cx36 contains a Mg(2+)-sensitive domain, and site-directed mutagenesis shows that the pore-lining residue D47 is critical in determining high Mg(2+)-sensitivity. Single-channel analysis of Mg(2+)-sensitive chimeras and mutants reveals that [Mg(2+)]i controls the strength of electrical coupling mostly via gating mechanisms. In addition, asymmetric transjunctional [Mg(2+)]i induces strong instantaneous rectification, providing a novel mechanism for electrical rectification in homotypic Cx36 GJs. We suggest that Mg(2+)-dependent synaptic plasticity of Cx36-containing electrical synapses could underlie neuronal circuit reconfiguration via changes in brain energy metabolism that affects neuronal levels of intracellular ATP and [Mg(2+)]i.
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Affiliation(s)
- Nicolás Palacios-Prado
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, NY 10461, USA
- Grass Laboratory, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Sandrine Chapuis
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, NY 10461, USA
| | - Alejandro Panjkovich
- European Molecular Biology Laboratory, Hamburg Outstation, 22603 Hamburg, Germany
| | - Julien Fregeac
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, NY 10461, USA
| | - James I. Nagy
- Department of Physiology, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada
| | - Feliksas F. Bukauskas
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, NY 10461, USA
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Salmina AB, Morgun AV, Kuvacheva NV, Lopatina OL, Komleva YK, Malinovskaya NA, Pozhilenkova EA. Establishment of neurogenic microenvironment in the neurovascular unit: the connexin 43 story. Rev Neurosci 2014; 25:97-111. [PMID: 24445236 DOI: 10.1515/revneuro-2013-0044] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 12/13/2013] [Indexed: 11/15/2022]
Abstract
Connexins (Cx) play an important role in the coordination of intercellular communication, and autocrine and paracrine regulation of cells within the neurovascular unit (NVU). Gap junctional mechanisms control proliferation and differentiation processes underlying neurogenesis and angiogenesis in the brain. Cx43 possesses some unique properties [the ability to form either intercellular channels permeable for regulatory molecules and ions or hemichannels open to the extracellular space to provide release of cell metabolites; functional coupling with nicotinamide adenine dinucleotide (NAD+)-consuming and NAD+-dependent enzymatic processes] which may be of great importance for the fate of the stem cells. Dynamic changes in Cx43 expression are associated with different stages of brain cells development either at embryonic or adult periods of ontogenesis. This review summarizes recent data on Cx43-controlled neurogenesis in the context of NVU development and functioning. Understanding the molecular mechanisms of gap junctional intercellular communication will support translational studies focused on the development of regeneration-based approaches for the therapy of central nervous system pathology.
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22
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Abstract
Cell–cell communication, facilitating the exchange of small metabolites, ions and second messengers, takes place via aqueous proteinaceous channels called gap junctions. Connexins (cx) are the subunits of a gap junction channel. Mutations in zebrafish cx43 produces the short fin (sof b123) phenotype and is characterized by short fins due to reduced segment length of the bony fin rays and reduced cell proliferation. Previously established results from our lab demonstrate that Cx43 plays a dual role regulating both cell proliferation (growth) and joint formation (patterning) during the process of skeletal morphogenesis. In this study, we show that Hapln1a (Hyaluronan and Proteoglycan Link Protein 1a) functions downstream of cx43. Hapln1a belongs to the family of link proteins that play an important role in stabilizing the ECM by linking the aggregates of hyaluronan and proteoglycans. We validated that hapln1a is expressed downstream of cx43 by in situ hybridization and quantitative RT-PCR methods. Moreover, in situ hybridization at different time points revealed that hapln1a expression peaks at 3 days post amputation. Expression of hapln1a is located in the medial mesenchyme and the in the lateral skeletal precursor cells. Furthermore, morpholino mediated knock-down of hapln1a resulted in reduced fin regenerate length, reduced bony segment length and reduced cell proliferation, recapitulating all the phenotypes of cx43 knock-down. Moreover, Hyaluronic Acid (HA) levels are dramatically reduced in hapln1a knock-down fins, attesting the importance of Hapln1a in stabilizing the ECM. Attempts to place hapln1a in our previously defined cx43–sema3d pathway suggest that hapln1a functions in a parallel genetic pathway. Collectively, our data suggest that Cx43 mediates independent Sema3d and Hapln1a pathways in order to coordinate skeletal growth and patterning.
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Affiliation(s)
- Jayalakshmi Govindan
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
| | - M. Kathryn Iovine
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America
- * E-mail:
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Han X, Tong XH, Dong SY, Zheng C, Yu BB. [Effects of retinoic acid on the expression of Cx43 and its gap juncion intercellular communication function in testicular cancer cell]. Sichuan Da Xue Xue Bao Yi Xue Ban 2013; 44:924-927. [PMID: 24490503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
OBJECTIVE To investigate the effects of retinoic acid (RA) on the expression of Cx43 and its gap junction intercellular communication function in testicular cancer cells. METHODS Cultured testicular cancer cells I-10 were treated with different concentration of RA (2.5, 5.0,10.0 micromol/L). The expression of Cx43 in 1-10 cells was detected by Western blot, and the distribution and location of Cx43 on cellular membrane was studied with immunofluorescence assay. Parachute assay was used to detect the function of gap junction intercellular communication composed of Cx43 in 1-10 cells. RESULTS RA (2.5, 5.0, 10.0 micromol/L) markedly increased the expression of Cx43 in I-10 cells, the enhancement ratios were 43.14% +/- 2.1%, 58.09% +/- 1.8%, 143.13% +/- 1.6%, respectively. The result of immunofluorescence assay showed that RA (2.5, 5.0, 10.0 micromol/L) obviously increased the level of Cx43 located on the cellular membrane of I-10 cells. The result of parachute assay demonstrated that RA (2.5,5.0,10.0 gmol/L) could enhance the intercellular dye coupling through gap junction, the enhancement ratios were 26.1% +/- 2.3%, 63.3% +/- 1.6%, 140.5% +/- 3.4%, respectively. CONCLUSION RA could enhance the gap junction intercellular communication by increasing the expression of Cx43 in I-10 cells.
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Affiliation(s)
- Xi Han
- Department of Pharmacology, Faculty of Pharmacy, Bengbu Medical College, Bengbu 233000, China
| | - Xu-Hui Tong
- Department of Pharmacology, Faculty of Pharmacy, Bengbu Medical College, Bengbu 233000, China
| | - Shu-Ying Dong
- Department of Pharmacology, Faculty of Pharmacy, Bengbu Medical College, Bengbu 233000, China
| | - Chao Zheng
- Department of Pharmacology, Faculty of Pharmacy, Bengbu Medical College, Bengbu 233000, China
| | - Bin-Bin Yu
- Department of Pharmacology, Faculty of Pharmacy, Bengbu Medical College, Bengbu 233000, China
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Abstract
Connexin43 (Cx43) is the most abundant gap junction protein expressed in bone cells and plays a central role in cell-to-cell communication in the skeleton. Findings of the last decade uncovered functions of Cx43 hemichannels expressed on unopposed plasma cell membranes as mediators of the communication between bone cells and their extracellular milieu. Additionally, through its cytoplasmic C-terminus domain, Cx43 serves as a scaffolding protein that associates with structural and signaling molecules leading to regulation of intracellular signaling, independent of channel activity. This perspective discusses the evidence demonstrating that via these diverse mechanisms Cx43 is a key component of the intracellular machinery responsible for signal transduction in bone in response to pharmacologic, hormonal and mechanical stimuli. This advance in the knowledge of the role of connexins increases our understanding of the pathophysiological mechanisms that regulate bone cell function and provides new opportunities to treat bone diseases.
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Affiliation(s)
- Lilian I. Plotkin
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN
| | - Teresita Bellido
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN
- Department of Medicine, Division of Endocrinology, Indiana University School of Medicine, Indianapolis, IN
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Mika T, Prochnow N. Functions of connexins and large pore channels on microglial cells: the gates to environment. Brain Res 2012; 1487:16-24. [PMID: 22842527 DOI: 10.1016/j.brainres.2012.07.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 07/08/2012] [Accepted: 07/10/2012] [Indexed: 12/12/2022]
Abstract
Microglial cells are not only sensitive indicators for pathology of the central nervous system (CNS), they are a key factor for neurotoxicity and degeneration in many diseases. Neuronal damage leads to reactive gliosis and to activation of microglia including cytoarchitectonic changes accompanied by alterations in surface receptor and channel expression. In this context, the release of neuroactive soluble factors like pro-inflammatory cytokines can result in increased cellular motility and a higher grade of phagocytotic activity. Ligands including glutamate, tumor necrosis factor alpha (TNF-α), cytokines, superoxide radicals and neurotrophins released by microglia have in turn effects on neuronal function and cell death. The current review focuses on large pore and hemichannel function in microglial cells under different conditions of activation and elucidates the role of these channels in cytokine release, as well as putative targets for clinical intervention in case of inflammatory processes. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Thomas Mika
- Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, D-44780 Bochum, Germany
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Ul-Hussain M, Dermietzel R, Zoidl G. Connexins and Cap-independent translation: role of internal ribosome entry sites. Brain Res 2012; 1487:99-106. [PMID: 22771397 DOI: 10.1016/j.brainres.2012.05.065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 05/18/2012] [Indexed: 02/05/2023]
Abstract
Cap-independent translation using an internal ribosome entry site instead of the 5'-Cap structure has been discovered in positive-sense RNA viruses and eukaryotic genomes including a subset of gap junction forming connexins genes. With a growing number of mutations found in human connexin genes and studies on genetically modified mouse models mechanisms highlighting the important role of gap junctional communication in multicellular organism it is obvious that mechanism need to be in place to preserve this critical property even under conditions when Cap-mediated translation is scrutinized. To ensure sustained gap junctional communication, rapid initiation of translation of preexisting connexin mRNAs is one possibility, and the presence of internal ribosome entry sites in gap junction genes comply with such a requirement. In this review, we will summarize past and recent findings to build a case for IRES mediated translation as an alternative regulatory pathway facilitating gap junctional communication. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Mahboob Ul-Hussain
- Biotechnology, University of Kashmir, India; Neuroanatomy, Ruhr-University, Bochum, Germany
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Iacobas S, Iacobas DA, Spray DC, Scemes E. The connexin43-dependent transcriptome during brain development: importance of genetic background. Brain Res 2012; 1487:131-9. [PMID: 22771707 PMCID: PMC3501561 DOI: 10.1016/j.brainres.2012.05.062] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 05/31/2012] [Indexed: 01/27/2023]
Abstract
Use of null mutant mice is a powerful way to evaluate the role of specific proteins in brain function. Studies performed on knockout mice have revealed some unexpected roles of the gap junction proteins (connexins). Thus, analyses of gene expression in connexin43 (Cx43) null brains indicated that deletion of a single gene (Gja1) induced expression level change of numerous other genes located on all chromosomes and involved in a wide diversity of functional pathways. The significant overlap between alterations in gene expression level, control and coordination in Cx43 knockout and knockdown astrocytes raised the possibility that Gja1 represents a transcriptomic node of gene regulatory networks. However, conditional deletion of Gja1 in astrocytes of two mouse strains resulted in remarkably different phenotypes. In order to evaluate the influence of the genetic background on the transcriptome, we performed microarray studies on brains of GFAP-Cre:Cx43(f/f) C57Bl/6 and 129/SvEv mice. The surprisingly low number of Cx43 core genes (regulated in all Cx43 nulls regardless of strain) and the high number of differently regulated genes in the two Cx43 conditional knockouts indicate high influence of mouse strain on brain transcriptome. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- S Iacobas
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1410, Pelham Parkway, Kennedy Center, Room 203, Bronx, NY 10461, USA
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Bennett MVL, Garré JM, Orellana JA, Bukauskas FF, Nedergaard M, Sáez JC. Connexin and pannexin hemichannels in inflammatory responses of glia and neurons. Brain Res 2012; 1487:3-15. [PMID: 22975435 DOI: 10.1016/j.brainres.2012.08.042] [Citation(s) in RCA: 162] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/11/2012] [Accepted: 08/22/2012] [Indexed: 11/17/2022]
Abstract
Mammals express ∼20 different connexins, the main gap junction forming proteins in mammals, and 3 pannexins, homologs of innexins, the main gap junction forming proteins in invertebrates. In both classes of gap junction, each channel is formed by two hemichannels, one contributed by each of the coupled cells. There is now general, if not universal, agreement that hemichannels of both classes can open in response to various physiological and pathological stimuli when they are not apposed to another hemichannels and face the external milieu. Connexin (and likely pannexin) hemichannel permeability is consistent with that of the cell-cell channels and open hemichannels can be a release site for relatively large molecules such as ATP and glutamate, which can serve as transmitters between cells. Here we describe three experimental paradigms in which connexin and pannexin hemichannel signaling occurs. (1) In cultures of spinal astrocytes FGF-1 causes the release of ATP, and ATP causes opening of pannexin hemichannels, which then release further ATP. Subsequently, several hours later, connexin hemichannels are also opened by an unknown mechanism. Release of ATP appears to become self sustaining through action of P2X7 receptors to open pannexin hemichannels and then connexin hemichannels, both of which are ATP permeable. (2) Spinal cord injury by dropping a small weight on the exposed cord is followed by release of ATP in the region surrounding the primary lesion. This release is greatly reduced in a mouse in which Cx43 is knocked down in the astrocytes. Application of FGF-1 causes a similar release of ATP in the uninjured spinal cord, and an inhibitor of the FGF-1 receptor, PD173074, inhibits both FGF-1 and injury-induced release. Reduction in ATP release is associated with reduced inflammation and less secondary expansion of the lesion. (3) Cortical astrocytes in culture are permeabilized by hypoxia, and this effect is increased by high or zero glucose. The mechanism of permeabilization is opening of Cx43 hemichannels, which can lead to cell death. Activated microglia secrete TNF-α and IL-1β, which open connexin hemichannels in astrocytes. Astrocytes release ATP and glutamate which can kill neurons in co-culture through activation of neuronal pannexin hemichannels. These studies implicate two kinds of gap junction hemichannel in inflammatory responses and cell death. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Michael V L Bennett
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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Ponsaerts R, D’hondt C, Hertens F, Parys JB, Leybaert L, Vereecke J, Himpens B, Bultynck G. RhoA GTPase switch controls Cx43-hemichannel activity through the contractile system. PLoS One 2012; 7:e42074. [PMID: 22860057 PMCID: PMC3408431 DOI: 10.1371/journal.pone.0042074] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 07/02/2012] [Indexed: 11/18/2022] Open
Abstract
ATP-dependent paracrine signaling, mediated via the release of ATP through plasma membrane-embedded hemichannels of the connexin family, coordinates a synchronized response between neighboring cells. Connexin 43 (Cx43) hemichannels that are present in the plasma membrane need to be tightly regulated to ensure cell viability. In monolayers of bovine corneal endothelial cells (BCEC),Cx43-mediated ATP release is strongly inhibited when the cells are treated with inflammatory mediators, in particular thrombin and histamine. In this study we investigated the involvement of RhoA activation in the inhibition of hemichannel-mediated ATP release in BCEC. We found that RhoA activation occurs rapidly and transiently upon thrombin treatment of BCEC. The RhoA activity correlated with the onset of actomyosin contractility that is involved in the inhibition of Cx43 hemichannels. RhoA activation and inhibition of Cx43-hemichannel activity were both prevented by pre-treatment of the cells with C3-toxin as well as knock down of RhoA by siRNA. These findings provide evidence that RhoA activation is a key player in thrombin-induced inhibition of Cx43-hemichannel activity. This study demonstrates that RhoA GTPase activity is involved in the acute inhibition of ATP-dependent paracrine signaling, mediated by Cx43 hemichannels, in response to the inflammatory mediator thrombin. Therefore, RhoA appears to be an important molecular switch that controls Cx43 hemichannel openings and hemichannel-mediated ATP-dependent paracrine intercellular communication under (patho)physiological conditions of stress.
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Affiliation(s)
- Raf Ponsaerts
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1, Faculty of Medicine, KU Leuven, Leuven, Belgium
- * E-mail: (RP); (GB)
| | - Catheleyne D’hondt
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Fréderic Hertens
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Jan B. Parys
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Johan Vereecke
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Bernard Himpens
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-1, Faculty of Medicine, KU Leuven, Leuven, Belgium
- * E-mail: (RP); (GB)
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Kang Z, Liu L, Spangler R, Spear C, Wang C, Gulen MF, Veenstra M, Ouyang W, Ransohoff RM, Li X. IL-17-induced Act1-mediated signaling is critical for cuprizone-induced demyelination. J Neurosci 2012; 32:8284-92. [PMID: 22699909 PMCID: PMC3412399 DOI: 10.1523/jneurosci.0841-12.2012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 04/03/2012] [Accepted: 04/27/2012] [Indexed: 12/21/2022] Open
Abstract
Cuprizone inhibits mitochondrial function and induces demyelination in the corpus callosum, which resembles pattern III lesions in multiple sclerosis patients. However, the molecular and cellular mechanism by which cuprizone induces demyelination remains unclear. Interleukin-17 (IL-17) secreted by T helper 17 cells and γδT cells are essential in the development of experimental autoimmune encephalomyelitis. In this study, we examined the importance of IL-17 signaling in cuprizone-induced demyelination. We found that mice deficient in IL-17A, IL-17 receptor C (IL-17RC), and adaptor protein Act1 (of IL-17R) all had reduced demyelination accompanied by lessened microglial and polydendrocyte cellular reactivity compared with that in wild-type mice in response to cuprizone feeding, demonstrating the essential role of IL-17-induced Act1-mediated signaling in cuprizone-induced demyelination. Importantly, specific deletion of Act1 in astrocytes reduced the severity of tissue injury in this model, indicating the critical role of CNS resident cells in the pathogenesis of cuprizone-induced demyelination. In cuprizone-fed mice, IL-17 was produced by CNS CD3(+) T cells, suggesting a source of IL-17 in CNS upon cuprizone treatment.
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Affiliation(s)
| | - Liping Liu
- Neuroinflammation Research Center, Department of Neuroscience, Cleveland Clinic, Cleveland, Ohio 44195, and
| | - Roo Spangler
- Neuroinflammation Research Center, Department of Neuroscience, Cleveland Clinic, Cleveland, Ohio 44195, and
| | - Charles Spear
- Neuroinflammation Research Center, Department of Neuroscience, Cleveland Clinic, Cleveland, Ohio 44195, and
| | | | | | - Mike Veenstra
- Neuroinflammation Research Center, Department of Neuroscience, Cleveland Clinic, Cleveland, Ohio 44195, and
| | - Wenjun Ouyang
- Genentech Inc., South San Francisco, California 94080
| | - Richard M. Ransohoff
- Neuroinflammation Research Center, Department of Neuroscience, Cleveland Clinic, Cleveland, Ohio 44195, and
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Mendoza-Naranjo A, Cormie P, Serrano AE, Hu R, O'Neill S, Wang CM, Thrasivoulou C, Power KT, White A, Serena T, Phillips ARJ, Becker DL. Targeting Cx43 and N-cadherin, which are abnormally upregulated in venous leg ulcers, influences migration, adhesion and activation of Rho GTPases. PLoS One 2012; 7:e37374. [PMID: 22615994 PMCID: PMC3352877 DOI: 10.1371/journal.pone.0037374] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 04/18/2012] [Indexed: 12/19/2022] Open
Abstract
Background Venous leg ulcers can be very hard to heal and represent a significant medical need with no effective therapeutic treatment currently available. Principal Findings In wound edge biopsies from human venous leg ulcers we found a striking upregulation of dermal N-cadherin, Zonula Occludens-1 and the gap junction protein Connexin43 (Cx43) compared to intact skin, and in stark contrast to the down-regulation of Cx43 expression seen in acute, healing wounds. We targeted the expression of these proteins in 3T3 fibroblasts to evaluate their role in venous leg ulcers healing. Knockdown of Cx43 and N-cadherin, but not Zonula Occludens-1, accelerated cell migration in a scratch wound-healing assay. Reducing Cx43 increased Golgi reorientation, whilst decreasing cell adhesion and proliferation. Furthermore, Connexin43 and N-cadherin knockdown led to profound effects on fibroblast cytoskeletal dynamics after scratch-wounding. The cells exhibited longer lamelipodial protrusions lacking the F-actin belt seen at the leading edge in wounded control cells. This phenotype was accompanied by augmented activation of Rac-1 and RhoA GTPases, as revealed by Förster Resonance Energy Transfer and pull down experiments. Conclusions Cx43 and N-cadherin are potential therapeutic targets in the promotion of healing of venous leg ulcers, by acting at least in part through distinct contributions of cell adhesion, migration, proliferation and cytoskeletal dynamics.
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Affiliation(s)
- Ariadna Mendoza-Naranjo
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
- * E-mail: (DLB); (AMN)
| | - Peter Cormie
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Antonio E. Serrano
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Rebecca Hu
- CoDa Therapeutics, Auckland, New Zealand
| | | | - Chiuhui Mary Wang
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | | | - Kieran T. Power
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | | | - Thomas Serena
- Newbridge Medical Research Corp, Warren, Pennsylvania, United States of America
| | | | - David L. Becker
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
- * E-mail: (DLB); (AMN)
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Chkourko HS, Guerrero-Serna G, Lin X, Darwish N, Pohlmann JR, Cook KE, Martens JR, Rothenberg E, Musa H, Delmar M. Remodeling of mechanical junctions and of microtubule-associated proteins accompany cardiac connexin43 lateralization. Heart Rhythm 2012; 9:1133-1140.e6. [PMID: 22406144 DOI: 10.1016/j.hrthm.2012.03.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Indexed: 11/18/2022]
Abstract
BACKGROUND Desmosomes and adherens junctions provide mechanical continuity between cardiac cells, whereas gap junctions allow for cell-cell electrical/metabolic coupling. These structures reside at the cardiac intercalated disc (ID). Also at the ID is the voltage-gated sodium channel (VGSC) complex. Functional interactions between desmosomes, gap junctions, and VGSC have been demonstrated. Separate studies show, under various conditions, reduced presence of gap junctions at the ID and redistribution of connexin43 (Cx43) to plaques oriented parallel to fiber direction (gap junction "lateralization"). OBJECTIVE To determine the mechanisms of Cx43 lateralization, and the fate of desmosomal and sodium channel molecules in the setting of Cx43 remodeling. METHODS Adult sheep were subjected to right ventricular pressure overload (pulmonary hypertension). Tissue was analyzed by quantitative confocal microscopy and by transmission electron microscopy. Ionic currents were measured using conventional patch clamp. RESULT Quantitative confocal microscopy demonstrated lateralization of immunoreactive junctional molecules. Desmosomes and gap junctions in lateral membranes were demonstrable by electron microscopy. Cx43/desmosomal remodeling was accompanied by lateralization of 2 microtubule-associated proteins relevant for Cx43 trafficking: EB1 and kinesin protein Kif5b. In contrast, molecules of the VGSC failed to reorganize in plaques discernable by confocal microscopy. Patch-clamp studies demonstrated change in amplitude and kinetics of sodium current and a small reduction in electrical coupling between cells. CONCLUSIONS Cx43 lateralization is part of a complex remodeling that includes mechanical and gap junctions but may exclude components of the VGSC. We speculate that lateralization results from redirectionality of microtubule-mediated forward trafficking. Remodeling of junctional complexes may preserve electrical synchrony under conditions that disrupt ID integrity.
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Affiliation(s)
- Halina S Chkourko
- The Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York, USA
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Abstract
BACKGROUND Several lines of evidence have suggested that maintenance of atrial fibrillation (AF) depends on reentrant mechanisms. Maintenance of reentry necessitates a sufficiently short refractory period and/or delayed conduction, and AF has been associated with both alterations. Fibrosis, cellular dysfunction, and gap junction protein alterations occur in AF and cause conduction delay. We performed this study to test the hypothesis that gap junction protein overexpression would improve conduction and prevent AF. METHODS AND RESULTS Thirty Yorkshire swine were randomized into 2 groups (sinus rhythm and AF), and each group into 3 subgroups: sham-operated control, gene therapy with adenovirus expressing connexin (Cx) 40, and gene therapy with adenovirus expressing Cx43 (n=5 per subgroup). All animals had epicardial gene painting; the AF group had burst atrial pacing. All animals underwent terminal study 7 days after gene transfer. Sinus rhythm animals had strong transgene expression but no atrial conduction changes. In AF animals, controls had reduced and lateralized Cx43 expression, and Cx43 gene transfer restored expression and cellular location to sinus rhythm control levels. In the AF group, both Cx40 and Cx43 gene transfer improved conduction and reduced AF relative to controls. CONCLUSIONS Connexin gene therapy preserved atrial conduction and prevented AF.
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Affiliation(s)
- Tomonori Igarashi
- Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, USA
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Yu ZB, Sheng JJ. [Remodeling of cardiac gap junctions and arrhythmias]. Sheng Li Xue Bao 2011; 63:586-92. [PMID: 22193455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In the heart, gap junctions mediate electrical and chemical coupling between adjacent cardiomyocytes, forming the cell-to-cell pathways for orderly spread of the wave of electrical excitation responsible for a functional syncytium. Three principal connexins are expressed in cardiomyocytes, connexin 43 (CX43), CX40, and CX45. CX43 predominates in ventricular muscle cells. Most of the gap junctions, assembled from CX43, are located at the intercalated discs, often with larger junctional plaques at the disc periphery. The gap junctions are rarely distributed to the sides of the cardiomyocyte. The ischemia-reperfusion, cardiac hypertrophy, heart failure, hypercholesterolemia, and diabetes mellitus induce gap junction remodeling. The gap junction remodeling induced by above-mentioned diseases shows similar characteristics, including down-regulation of CX43, reduction in gap junction plaque size, increased heterogeneity and lateralization of gap junction distribution, and dephosphorylation of CX43. The elevated angiotensin II concentration in local myocardium may play an important role in the gap junction remodeling. The down-regulation of CX43 and lateralization of gap junction distribution alter anisotropic spread of the impulse of ventricular myocardium. The dephosphorylation of CX43 not only reduces electrical conductance, but also decreases permeability of chemicals between cardiomyocytes. The lateralization of gap junctions may increase the number of hemichannels formed by CX43. The opening of hemichannels induces ATP efflux and Na(+) influx, which forms a delayed after-depolarization. The gap junction remodeling in pathological condition produces arrhythmia substrate in the ventricles. In this review, the current knowledge on the relationship between the remodeling of cardiac gap junctions and arrhythmias were summarized.
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Affiliation(s)
- Zhi-Bin Yu
- Department of Aerospace Physiology, the Fourth Military Medical University, Xi'an 710032, China.
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Abstract
Intercalated disc structures have conventionally been considered to be independent. Recent work shows that molecules initially thought of as belonging to one complex can actually affect another. Here, I focus on the cross-talk between connexin43 (Cx43, 'the gap junction protein') and the sodium channel complex and, conversely, on ankyrin-G (AnkG, a 'component of the sodium channel complex') and gap junctions. I speculate as to the possibility that one molecule affects the function of the other by regulating its trafficking into the intercalated disc.
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Boeldt DS, Yi FX, Bird IM. eNOS activation and NO function: pregnancy adaptive programming of capacitative entry responses alters nitric oxide (NO) output in vascular endothelium--new insights into eNOS regulation through adaptive cell signaling. J Endocrinol 2011; 210:243-58. [PMID: 21555345 PMCID: PMC4059042 DOI: 10.1530/joe-11-0053] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In pregnancy, vascular nitric oxide (NO) production is increased in the systemic and more so in the uterine vasculature, thereby supporting maximal perfusion of the uterus. This high level of functionality is matched in the umbilical vein, and in corresponding disease states such as pre-eclampsia, reduced vascular responses are seen in both uterine artery and umbilical vein. In any endothelial cell, NO actually produced by endothelial NO synthase (eNOS) is determined by the maximum capacity of the cell (eNOS expression levels), eNOS phosphorylation state, and the intracellular [Ca(2+)](i) concentration in response to circulating hormones or physical forces. Herein, we discuss how pregnancy-specific reprogramming of NO output is determined as much by pregnancy adaptation of [Ca(2+)](i) signaling responses as it is by eNOS expression and phosphorylation. By examining the changes in [Ca(2+)](i) signaling responses from human hand vein endothelial cells, uterine artery endothelial cells, and human umbilical vein endothelial cells in (where appropriate) nonpregnant, normal pregnant, and pathological pregnant (pre-eclamptic) state, it is clear that pregnancy adaptation of NO output occurs at the level of sustained phase 'capacitative entry' [Ca(2+)](i) response, and the adapted response is lacking in pre-eclamptic pregnancies. Moreover, gap junction function is an essential permissive regulator of the capacitative response and impairment of NO output results from any inhibitor of gap junction function, or capacitative entry using TRPC channels. Identifying these [Ca(2+)](i) signaling mechanisms underlying normal pregnancy adaptation of NO output not only provides novel targets for future treatment of diseases of pregnancy but may also apply to other common forms of hypertension.
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Affiliation(s)
- D S Boeldt
- Perinatal Research Laboratories, Department of Obstetrics and Gynecology, University of Wisconsin-Madison, 7E Meriter Hospital/Park, 202 South Park Street, Madison, WI 53715, USA
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Negoro H, Kanematsu A, Imamura M, Kimura Y, Matsuoka R, Tanaka M, Tabata Y, Ogawa O. Regulation of connexin 43 by basic fibroblast growth factor in the bladder: transcriptional and behavioral implications. J Urol 2011; 185:2398-404. [PMID: 21511298 DOI: 10.1016/j.juro.2011.02.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Indexed: 11/18/2022]
Abstract
PURPOSE Basic fibroblast growth factor is a candidate causative factor of detrusor overactivity in bladder outlet obstruction cases through up-regulation of the gap junction protein connexin 43. We addressed the transcriptional and behavioral implications of this axis. MATERIALS AND METHODS Cx43 and Cx45 mRNA expression was assessed by real-time reverse transcriptase-polymerase chain reaction in the bladder of a rat bladder outlet obstruction model and in cultured rat bladder smooth muscle cells with and without basic fibroblast growth factor treatment. Involvement of the extracellular signal regulated kinase 1/2-activator protein-1 pathway was evaluated by immunofluorescence study and a promoter-reporter assay in bladder smooth muscle cells. The effect of basic fibroblast growth factor on micturition behavior was measured in unrestrained rats under a 12-hour light/dark cycle using a controlled release system from gelatin hydrogels fixed on the bladder. The expression of extracellular signal regulated kinase 1/2 and connexin 43 protein was assessed by Western blotting of rat bladder protein. RESULTS Cx43 but not Cx45 mRNA expression was increased in the bladder of the obstruction model and in bladder smooth muscle cells treated with basic fibroblast growth factor. The mitogen-activated and extracellular signal-regulated kinase kinase inhibitor PD98059 blocked the stimulatory effect of basic fibroblast growth factor on connexin 43 protein expression and promoter activity, which was also decreased by mutation or deletion of an activator protein-1 cis-element of the connexin 43 promoter. In vivo application of basic fibroblast growth factor on the bladder increased urinary frequency during the latter half of the dark phase, ie the late active phase of rats (F = 5.1, 2-way ANOVA p <0.05). The expression of phospho-extracellular signal regulated kinase 1/2 and connexin 43 protein was increased in the bladder. CONCLUSIONS The extracellular signal regulated kinase 1/2-activator protein-1-connexin 43 axis could be a potential therapeutic target for increased urinary frequency.
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40
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Abstract
Atrial fibrillation (AF), the most common cardiac arrhythmia seen in general practice, can be promoted by conduction slowing. Cardiac impulse conduction depends on gap junction channels, which are composed of connexins (Cxs). While atrial Cx40 and Cx43 are equally expressed, AF studies have primarily focused on Cx40 reductions. The G60S Cx43 mutant (Cx43(G60S/+)) mouse model of Oculodentodigital dysplasia has a 60% reduction in Cx43 in the atria. Cx43(G60S/+) mice were compared with Cx40-deficient (Cx40(-/-)) mice to determine the role of Cxs in atrial tachycardia/fibrillation (AT/F). Intracardiac electrophysiological studies were done in 6-mo-old male C57BL/6 Cx43(G60S/+) mutant, littermate (Cx43(+/+)), Cx40(-/-), and C57BL/6 wild-type (WT) mice. AT/F induction used an extra stimulus during sinus rhythm, programmed electrical stimulation, or burst pacing (1-ms pulses, 50-Hz, 400-ms train) in the absence and presence of carbachol (CCh). Atrial effective refractory periods did not differ between strains. Cx43(G60S/+) mice were more susceptible to induction of sustained AT/F (duration >2 min, 9 of 12; maximum >35 min) compared with Cx43(+/+) mice (3 of 11; χ(2) = 5.24; P = 0.02). CCh enhanced sustained AT/F susceptibility in WT (from 1 of 12 without, to 7 of 10 with CCh; χ(2) = 8.98; P < 0.01) but not in Cx40(-/-) mice (1 of 13 without vs. 2 of 9 with CCh; χ(2) = 0.95; P = NS). The pattern of epicardial recordings during AT/F in Cx43(G60S/+) mice was left preceding right, with left atrial fractionated activation patterns consistent with clinical observations of AF. In conclusions, while Cx43(G60S/+) mice had severe AT/F, Cx40(-/-) mice were resistant to CCh-induced AT/F.
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Affiliation(s)
- Jari M Tuomi
- Department of Physiology and Pharmacology, University of Western Ontario, London, Canada
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Pawlik A, Alibert O, Baulande S, Vaigot P, Tronik-Le Roux D. Transcriptome characterization uncovers the molecular response of hematopoietic cells to ionizing radiation. Radiat Res 2011; 175:66-82. [PMID: 21175349 DOI: 10.1667/rr2282.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Ionizing radiation causes rapid and acute suppression of hematopoietic cells that manifests as the hematopoietic syndrome. However, the roles of molecules and regulatory pathways induced in vivo by irradiation of different hematopoietic cells have not been completely elaborated. Using a strategy that combined different microarray bioinformatics tools, we identified gene networks that might be involved in the early response of hematopoietic cells radiation response in vivo. The grouping of similar time-ordered gene expression profiles using quality threshold clustering enabled the successful identification of common binding sites for 56 transcription factors that may be involved in the regulation of the early radiation response. We also identified novel genes that are responsive to the transformation-related protein 53; all of these genes were biologically validated in p53-transgenic null mice. Extension of the analysis to purified bone marrow cells including highly purified long-term hematopoietic stem cells, combined with functional classification, provided evidence of gene expression modifications that were largely unknown in this primitive population. Our methodology proved particularly useful for analyzing the transcriptional regulation of the complex ionizing radiation response of hematopoietic cells. Our data may help to elucidate the molecular mechanisms involved in tissue radiosensitivity and to identify potential targets for improving treatment in radiation emergencies.
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42
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Zhang S, Liang R, Zhou F, Huang X, Ding JH, Hu G. Reversal of rotenone-induced dysfunction of astrocytic connexin43 by opening mitochondrial ATP-sensitive potassium channels. Cell Mol Neurobiol 2010; 31:111-7. [PMID: 20824494 DOI: 10.1007/s10571-010-9560-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 08/25/2010] [Indexed: 12/21/2022]
Abstract
Growing evidence suggests that the astrocytic gap junctions (GJs), mainly formed by connexin 43 (Cx43), play an important role in physiological maintenance and various central nervous system (CNS) pathological conditions. However, little is known about the role of Cx43 in Parkinson's disease (PD). In this article, we report that rotenone, a classic neurotoxin for PD, could inhibit expression of astrocytic Cx43 and gap junction permeability. ATP-sensitive potassium (K(ATP)) channel openers, iptakalim (IPT) and diazoxide (DZ), exerted protective effect on rotenone-induced dysfunction of Cx43 and astrocyte apoptosis, which was reversed by selective mitochondrial K(ATP) (mitoK(ATP)) channel blocker 5-hydroxydecanoate (5-HD). Taken together, our findings reveal that rotenone-induced dysfunction of astrocytic Cx43 may be involved in the pathology of PD. Moreover, opening mitoK(ATP) channels in astrocytes can reverse rotenone-induced dysfunction of astrocytic Cx43 and therefore protect against toxicity of rotenone on astrocytes.
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Affiliation(s)
- Shu Zhang
- Department of Pharmacology, Nanjing Medical University, Jiangsu, People's Republic of China
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43
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Song D, Liu X, Liu R, Yang L, Zuo J, Liu W. Connexin 43 hemichannel regulates H9c2 cell proliferation by modulating intracellular ATP and [Ca2+]. Acta Biochim Biophys Sin (Shanghai) 2010; 42:472-82. [PMID: 20705586 DOI: 10.1093/abbs/gmq047] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Connexin 43 (Cx43), known to be the main protein building blocks of gap junctions and hemichannels in mammalian heart, plays an important role in cardiocytes proliferation. Gap junctional intercellular communication has been suggested to be necessary for cellular proliferation and differentiation. However, the effect of Cx43 hemichannel on cardiocytes proliferation and the mechanism remain unclear. In this study, rat heart cell line H9c2 was used. The Cx43 location, the proliferation rate and hemichannel activity of H9c2 cells and Wnt-3a(+)-H9c2 cells were investigated and the changes of intracellular ATP and [Ca(2+)] were determined. Results showed that the inhibited hemichannel induced by 18beta-glycyrrhetinic acid (GA) evoked intracellular ATP and [Ca(2+)] increase and enhanced H9c2 cell proliferation. Wnt-3a(+)-H9c2 cells displayed enhanced hemichannel activity and proliferation rate. Inhibited hemichannel of Wnt-3a(+)-H9c2 cells induced by 18beta-GA decreased intracellular ATP, increased [Ca(2+)], and enhanced the proliferation of H9c2 cells. This study validated the role of hemichannel in H9c2 cell proliferation regulation, and showed a mechanism involved in the regulation of H9c2 cell proliferation. The proliferation could be enhanced by Cx43 hemichannel-mediated ATP release accompanying intracellular [Ca(2+)] change. However, different changes of ATP were observed in Wnt-3a(+)-H9c2 cells. These findings provided new insights into the molecular mechanisms of proliferation regulation in H9c2 cells and the effect of Wnt-3a on intracellular ATP.
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Affiliation(s)
- Dongli Song
- Department of Cellular and Genetic Medicine, Fudan University, Shanghai, China
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44
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Han JH, Kim KA, Shah A, Park BH, Park WH, Kim SH. Regulation of renin release by connexin 43 in As 4.1 cell line. Peptides 2010; 31:899-902. [PMID: 20188775 DOI: 10.1016/j.peptides.2010.02.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Revised: 02/17/2010] [Accepted: 02/17/2010] [Indexed: 10/19/2022]
Abstract
Gap junction channels facilitate chemical and electrical communication between adjacent cells. Gap junction protein, connexin (Cx), is expressed in the endothelial cells of vessels, glomerulus, and renin-secreting cells of the kidney. The purpose of this study was to investigate the role of Cx in renin release using Cx-overexpressing As 4.1 cells. The adenovirus-induced Cx overexpression was conducted by using recombinant adenovirus containing the cDNA encoding Cx37, Cx40, Cx43 (Ad-Cx), and beta-galactosidase (Ad-beta-gal). In 40-overexpressing cells, basal renin release increased in a time-dependent manner but it was significantly lower than that in Ad-beta-gal-treated cells. In Cx37- and Cx43-overexpressing cells, basal renin release was increased in a time-dependent manner, which was not different from control cells. 18-beta glycyrrhetinic acid (GA), a gap junction blocker, stimulated renin release dose-dependently and increased intracellular Ca(2+) in both Cx43-overexpressing cells and control cells. However, no significant differences were observed. An increase in renin release by 3,4,5-trimethoxybenzoic acid 8-(diethylamino)-octyl ester, a putative antagonist of Ca(2+) release from intracellular sequestration sites, was also similar between two groups. These results suggest that Cx43 may unlikely alter the regulation of renin release and intracellular Ca(2+) by gap junction blocker in As 4.1 cells.
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Affiliation(s)
- Jeong Hee Han
- Department of Physiology, Diabetic Research Center, Chonbuk National University Medical School, Jeonju, Republic of Korea
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45
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Rodríguez-Sinovas A, Sánchez JA, González-Loyola A, Barba I, Morente M, Aguilar R, Agulló E, Miró-Casas E, Esquerda N, Ruiz-Meana M, García-Dorado D. Effects of substitution of Cx43 by Cx32 on myocardial energy metabolism, tolerance to ischaemia and preconditioning protection. J Physiol 2010; 588:1139-51. [PMID: 20156849 PMCID: PMC2853001 DOI: 10.1113/jphysiol.2009.186577] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 02/08/2010] [Indexed: 12/31/2022] Open
Abstract
Connexin 43 (Cx43) plays an important role in cardioprotective signalling by mechanisms at least in part independent of gap junctional communication. To investigate whether this role is related to specific properties of this connexin isoform, we used a knock-in mouse model in which the coding region of Cx43 is replaced by that of Cx32. Homozygous Cx43KI32 mice showed reduced cell-to-cell Lucifer Yellow transfer (P < 0.01), but QRS duration and left ventricular fractional shortening (echocardiography) were similar to those in wild-type animals. NMR spectroscopy detected reduced ATP and increased lactate content in myocardium from homozygous Cx43KI32 animals (P < 0.05). Despite this, isolated homozygous Cx43KI32 hearts showed smaller infarcts after ischaemia-reperfusion (40 min/60 min) as compared to hearts from heterozygous and wild-type animals (13 and 31% reduction, respectively, P < 0.05). Cardiac myocytes isolated from Cx43KI32 mouse hearts also showed a reduced rate of cell death after simulated ischaemia-reperfusion. In a separate series of experiments, both ischaemic (4 cycles of 3.5 min of ischaemia and 5 min of reperfusion) and pharmacological (50 micromol l(-1) diazoxide, 10 min) preconditioning reduced infarct size in hearts from wild-type mice (by 24.84 and 26.63%, respectively, P < 0.05), but only ischaemic preconditioning was effective in hearts from heterozygous animals and both preconditioning strategies failed to protect Cx43KI32 homozygous hearts. These results demonstrate that Cx43 has an important and previously unknown modulatory effect in myocardial energy metabolism and tolerance to ischaemia, and plays a critical role in preconditioning protection, by mechanisms that are specific for this connexin isoform.
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Affiliation(s)
- Antonio Rodríguez-Sinovas
- Laboratorio de Cardiología Experimental, Servicio de Cardiología, Hospital Universitari Vall d'Hebron, Barcelona, Spain
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Nagata K, Masumoto K, Esumi G, Teshiba R, Yoshizaki K, Fukumoto S, Nonaka K, Taguchi T. Connexin43 plays an important role in lung development. J Pediatr Surg 2009; 44:2296-301. [PMID: 20006013 DOI: 10.1016/j.jpedsurg.2009.07.070] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Accepted: 07/31/2009] [Indexed: 11/17/2022]
Abstract
OBJECTIVES Connexin43 (Cx43) is one of the proteins associated with gap junction. Connexin43 knockout mice die after birth owing to hypoplastic lungs. The purpose of this study was to analyze the hypoplastic lung of Cx43 knockout mice to clarify the role of the Cx43 during lung development. METHODS Adult hetero Cx43 mice were mated. Newborn mice were divided into the following groups: wild, hetero, and knockout. Total RNA was extracted from the right lung, and the left lung was fixed for immunohistochemical staining. The mRNA expression of surfactant protein C, aquaporin-5, and alpha-smooth muscle actin were analyzed by reverse transcriptase polymerase chain reaction. H&E and immunohistochemical staining for those markers were performed. RESULTS The mRNA expression of aquaporin-5, surfactant protein C, and alpha-smooth muscle actin was significantly lower in knockout mice than that in the wild and hetero mice. H&E staining in the knockout mice showed narrow airspaces and thicker interalveolar septae. Immunohistochemical staining in all markers showed the formation of alveoli to be delayed in the knockout mice. CONCLUSION Based on these findings, Cx43 is closely related to alveolar and vascular formation during lung development.
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Affiliation(s)
- Kouji Nagata
- Department of Pediatric Surgery, Reproductive and Developmental Medicine, Kyushu University, Fukuoka 812-8582, Japan.
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Abstract
Connexin40 (Cx40) is a major gap-junction protein in the atrial myocardium. In the heart, gap junctions are responsible for cell-to-cell conduction of the action potential. In several cardiac diseases, the expression of connexins is changed and is associated with increased propensity for arrhythmias. Atrial fibrillation (AF) is the most common arrhythmia in man with a diverse clinical presentation, different underlying mechanisms, and difficult treatment. The vulnerability to arrhythmias of the heart is determined by the combined presence of an arrhythmogenic substrate and initiating triggers. The arrhythmogenic substrate is formed by reduced effective refractory period, enhanced spatial dispersion of refractoriness, or abnormal atrial impulse conduction. Initiating triggers of AF most frequently originate from firing foci in the pulmonary veins and/or superior caval vein. Prolonged episodes of AF result in electrical and structural remodelling that favours the reoccurrence or perpetuation of AF. This electrical remodelling embodies changes in Cx40 expression and distribution, both in the atrial myocardium itself and in the thoracic veins. In addition, Cx40 gene mutations or polymorphisms give an inherited predisposition to AF. This review focuses on the role of Cx40 in AF, showing that abnormal Cx40 expression is correlated with both trigger formation from the thoracic veins as well as enhanced vulnerability of the atrial myocardium to AF.
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Affiliation(s)
- Sevasti-Maria Chaldoupi
- Department of Cardiology, Division Heart and Lungs, University Medical Center Utrecht, The Netherlands
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López D, Rodríguez-Sinovas A, Agulló E, García A, Sánchez JA, García-Dorado D. Replacement of connexin 43 by connexin 32 in a knock-in mice model attenuates aortic endothelium-derived hyperpolarizing factor-mediated relaxation. Exp Physiol 2009; 94:1088-97. [PMID: 19617266 DOI: 10.1113/expphysiol.2009.048413] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous studies demonstrated that intercellular communication through endothelial, smooth muscle or myoendothelial connexin channels contributes to the control of vascular tone. At least four connexin types are present in the arterial wall. The aim of the present work was to assess the role played by connexin 43 (Cx43)-formed gap junctions on vessel function. Aortic reactivity to noradrenaline, acetylcholine and sodium nitroprusside, and endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxations, were analysed in a Cx43KI32 mouse model in which the coding region of Cx43 was replaced by that of connexin 32 (Cx32). Aortic rings were placed in organ baths containing a Krebs solution oxygenated at 37 degrees C (pH 7.4). Confocal images of aortic rings confirmed connexin substitution in mutant mice. In control conditions, replacement of Cx43 by Cx32 in homozygous mutant mice did not modify endothelium-independent contractile responses to noradrenaline, or relaxations in response to sodium nitroprusside (endothelium independent) or acetylcholine (endothelium dependent). However, residual endothelium-dependent relaxations in response to acetylcholine after nitric oxide synthase and cyclooxygenase inhibition (EDHF type) were significantly reduced in homozygous Cx43KI32 mice (maximal effect values: 4.86 +/- 0.37% of noradrenaline precontraction versus 7.06 +/- 0.31% in wild-type, n = 8, P < 0.05). This attenuation was mimicked by treatment of rings from wild-type animals with the connexin-mimetic peptide (37,43)Gap27 (5 x 10(-6)m). In conclusion, replacement of Cx43 by Cx32 attenuates EDHF-mediated relaxations in mice aortic rings, suggesting that they are, at least in part, dependent on Cx43-formed gap junctions. In contrast, aortic responses to tested endothelium-independent agonists were not modified in knock-in animals.
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Affiliation(s)
- Diego López
- Institut de Recerca Hospitals Vall d'Hebron, Hospital Universitario Vall d'Hebron, Passeig Vall d'Hebron 119, 08035 Barcelona, Spain
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Majoul IV, Onichtchouk D, Butkevich E, Wenzel D, Chailakhyan LM, Duden R. Limiting transport steps and novel interactions of Connexin-43 along the secretory pathway. Histochem Cell Biol 2009; 132:263-80. [PMID: 19626334 PMCID: PMC2756399 DOI: 10.1007/s00418-009-0617-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/12/2009] [Indexed: 12/25/2022]
Abstract
Connexins are four-transmembrane-domain proteins expressed in all vertebrates which form permeable gap junction channels that connect cells. Here, we analysed Connexin-43 (Cx43) transport to the plasma membrane and studied the effects of small GTPases acting along the secretory pathway. We show that both GTP- and GDP-restricted Sar1 prevents exit of Cx43 from the endoplasmic reticulum (ER), but only GTP-restricted Sar1 arrests Cx43 in COP II-coated ER exit sites and accumulates 14-3-3 proteins in the ER fraction. FRET-FLIM data confirm that already in ER exit sites Cx43 exists in oligomeric form, suggesting an in vivo role for 14-3-3 in Cx43 oligomerization. Exit of Cx43 from the ER can be blocked by other factors—such as expression of the β subunit of the COP I coat or p50/dynamitin that acts on the microtubule-based dynein motor complex. GTP-restricted Arf1 blocks Cx43 in the Golgi. Lastly, we show that GTP-restricted Arf6 removes Cx43 gap junction plaques from the cell–cell interface and targets them to degradation. These data provide a molecular explanation of how small GTPases act to regulate Cx43 transport through the secretory pathway, facilitating or abolishing cell–cell communication through gap junctions.
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Affiliation(s)
- Irina V. Majoul
- Institute of Biology, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
| | - Daria Onichtchouk
- Developmental Biology Unit, Department of Biology I, University of Freiburg, Freiburg, Germany
| | - Eugenia Butkevich
- Department of Neurophysiology, University of Göttingen, Göttingen, Germany
| | - Dirk Wenzel
- Department of Neurobiology, Max-Planck-Institute of Biophysical Chemistry, Göttingen, Germany
| | - Levon M. Chailakhyan
- Department of Cellular Biophysics and Intercellular Communications, Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Moscow, Russia
| | - Rainer Duden
- Institute of Biology, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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Heyman NS, Kurjiaka DT, Ek Vitorin JF, Burt JM. Regulation of gap junctional charge selectivity in cells coexpressing connexin 40 and connexin 43. Am J Physiol Heart Circ Physiol 2009; 297:H450-9. [PMID: 19465552 PMCID: PMC2711728 DOI: 10.1152/ajpheart.00287.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Accepted: 05/20/2009] [Indexed: 11/22/2022]
Abstract
Expression of connexin 40 (Cx40) and Cx43 in cardiovascular tissues varies as a function of age, injury, and development with unknown consequences on the selectivity of junctional communication and its acute regulation. We investigated the PKC-dependent regulation of charge selectivity in junctions composed of Cx43, Cx40, or both by simultaneous assessment of junctional permeance rate constants (B(dye)) for dyes of similar size but opposite charge, N,N,N-trimethyl-2-[methyl-(7-nitro-2,1,3-benzoxadiol-4-yl)amino]ethanaminium (NBD-M-TMA; +1) and Alexa 350 (-1). The ratio of dye rate constants (B(NBD-M-TMA)/B(Alexa 350)) indicated that Cx40 junctions are cation selective (10.7 +/- 0.5), whereas Cx43 junction are nonselective (1.22 +/- 0.14). In coexpressing cells, a broad range of junctional selectivities was observed with mean cation selectivity increasing as the Cx40 to Cx43 expression ratio increased. PKC activation reduced or eliminated dye permeability of Cx43 junctions without altering their charge selectivity, had no effect on either permeability or charge selectivity of Cx40 junctions, and significantly increased the cation selectivity of junctions formed by coexpressing cells (approaching charge selectivity of Cx40 junctions). Junctions composed of Cx43 truncated at residue 257 (Cx43tr) were also not charge selective, but when Cx43tr was coexpressed with Cx40, a broad range of junctional selectivities that was unaffected by PKC activation was observed. Thus, whereas the charge selectivities of homomeric/homotypic Cx43 and Cx40 junctions appear invariant, the selectivities of junctions formed by cells coexpressing Cx40 and Cx43 vary considerably, reflecting both their relative expression levels and phosphorylation-dependent regulation. Such regulation could represent a mechanism by which coexpressing cells such as vascular endothelium and atrial cells regulate acutely the selective intercellular communication mediated by their gap junctions.
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