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Gao Y, Chen C, Liu R, Zhang Z, Zhao X, Ma H. Research progress of connexin 43 mediated gap junction communication regulating bone metabolism in glucocorticoid-induced osteonecrosis of the femoral head. Exp Cell Res 2025; 449:114598. [PMID: 40339781 DOI: 10.1016/j.yexcr.2025.114598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2024] [Revised: 05/05/2025] [Accepted: 05/05/2025] [Indexed: 05/10/2025]
Abstract
Osteonecrosis of the femoral head (ONFH) is a refractory orthopedic disease that commonly affects young and middle-aged individuals. Long-term and high-dose use of glucocorticoids (GCs) is one of the main causes. Currently, the pathological mechanism of GCs-induced ONFH remains unclear, which poses difficulties for clinical prevention and treatment. This article focuses on reviewing the roles of gap junctions (GJs) and connexin 43 (Cx43) in GCs-induced ONFH. Under normal circumstances, cells in bone tissue form a network structure through GJs to maintain bone metabolic balance. However, GCs can obstruct the normal connections and signal transmission between bone tissue cells, leading to bone metabolic imbalance and triggering ONFH. As a key component of GJs in bone tissue, Cx43 is of great significance in bone metabolism. It not only participates in the construction of the osteocyte network but also regulates osteocyte activity, osteoblast differentiation, and osteogenic activities. Meanwhile, in vascular endothelial cells, Cx43 plays an important role in angiogenesis and maintaining vascular homeostasis, and is closely related to the vascularization of bone tissue. In addition, Cx43 is associated with the release of prostaglandin E2 (PGE2). GCs can inhibit the activity of Cx43, reduce the release of PGE2, and disrupt the balance of bone metabolism. Studies have shown that measuring changes in the expression level of Cx43 is expected to become an early diagnostic biomarker for GCs-induced ONFH. Enhancing its expression through small - molecule drugs, biological agents, and gene therapy may be potential treatment approaches for ONFH. This article proposes the PI3K/Akt/GSK3β/β-catenin pathway and conducts research on the regulatory mechanism of Cx43-mediated GJ-based intercellular communication, aiming to provide new ideas for the treatment of ONFH and bone metabolism-related diseases.
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Affiliation(s)
- Yang Gao
- Department of Orthopaedics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, People's Republic of China
| | - Changjun Chen
- Department of Orthopedics, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, People's Republic of China
| | - Rongxing Liu
- Department of Orthopaedics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, People's Republic of China
| | - Zhongkai Zhang
- Department of Orthopaedics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, People's Republic of China
| | - Xin Zhao
- Department of Orthopaedics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, People's Republic of China.
| | - Huanzhi Ma
- Department of Orthopaedics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, People's Republic of China.
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2
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Latchford LP, Perez LS, Conage-Pough JE, Turk R, Cusimano MA, Vargas VI, Arora S, Shienvold SR, Kulp RR, Belverio HM, White FM, Thévenin AF. Differential substrate specificity of ERK, JNK, and p38 MAP kinases toward connexin 43. J Biol Chem 2025; 301:108178. [PMID: 39798878 PMCID: PMC11870265 DOI: 10.1016/j.jbc.2025.108178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 12/18/2024] [Accepted: 01/03/2025] [Indexed: 01/15/2025] Open
Abstract
Phosphorylation of connexin 43 (Cx43) is an important regulatory mechanism of gap junction (GJ) function. Cx43 is modified by several kinases on over 15 sites within its ∼140 amino acid-long C-terminus (CT). Phosphorylation of Cx43CT on S255, S262, S279, and S282 by ERK has been widely documented in several cell lines, by many investigators. Phosphorylation of these sites by JNK and p38, on the other hand, is not well-established. Indeed, ERK is a kinase activated by growth factors and is upregulated in diseases, such as cancer. JNK and p38, however, have a largely tumor-suppressive function due to their stress-activated and apoptotic role. We investigated substrate specificity of all three MAPKs toward Cx43CT, first by using purified proteins, and then in two cell lines (MDCK - non-cancerous, epithelial cells and porcine PAECs-pulmonary artery endothelial cells). Cx43 phosphorylation was monitored through gel-shift assays on an SDS-PAGE, immunodetection with phospho-Cx43 antibodies, and LC-MS/MS phosphoproteomic analyses. Our results demonstrate that p38 and JNK specificity differ from each other and from ERK. JNK has a strong preference for S255, S262, and S279, while p38 readily phosphorylates S262, S279, and S282. While we confirmed that ERK can phosphorylate all four serines (255, 262, 279, and 282), we also identified T290 as a novel ERK phosphorylation site. In addition, we assessed Cx43 GJ function upon activation or inhibition of each MAPK in PAECs. This work underscores the importance of delineating the effects of ERK, JNK, and p38 signaling on Cx43 and GJ function.
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Affiliation(s)
- Lauren P Latchford
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA
| | - Liz S Perez
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA
| | - Jason E Conage-Pough
- Koch Institute for Integrative Cancer Research and Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA
| | - Reem Turk
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA
| | - Marissa A Cusimano
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA
| | - Victoria I Vargas
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA
| | - Sonal Arora
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA
| | - Sophia R Shienvold
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA
| | - Ryan R Kulp
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA
| | - Hailey M Belverio
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA
| | - Forest M White
- Koch Institute for Integrative Cancer Research and Department of Biological Engineering, MIT, Cambridge, Massachusetts, USA
| | - Anastasia F Thévenin
- Department of Biological Sciences, Moravian University, Bethlehem, Pennsylvania, USA.
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3
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Tishchenko A, Romero N, Van Waesberghe C, Delva JL, Vickman O, Smith GA, Mettenleiter TC, Fuchs W, Klupp BG, Favoreel HW. Pseudorabies virus infection triggers pUL46-mediated phosphorylation of connexin-43 and closure of gap junctions to promote intercellular virus spread. PLoS Pathog 2025; 21:e1012895. [PMID: 39836710 PMCID: PMC11774492 DOI: 10.1371/journal.ppat.1012895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2024] [Revised: 01/28/2025] [Accepted: 01/08/2025] [Indexed: 01/23/2025] Open
Abstract
Gap junctions (GJs) play a pivotal role in intercellular communication between eukaryotic cells, including transfer of biomolecules that contribute to the innate and adaptive immune response. However, if, how and why viruses affect gap junction intercellular communication (GJIC) remains largely unexplored. Here, we describe how the alphaherpesvirus pseudorabies virus (PRV) triggers ERK1/2-mediated phosphorylation of the main gap junction component connexin 43 (Cx43) and closure of GJIC, which depends on the viral protein pUL46. Consequently, a UL46null PRV mutant is unable to phosphorylate Cx43 or inhibit GJIC and displays reduced intercellular spread, which is effectively rescued by pharmacological inhibition of GJIC. Intercellular spread of UL46null PRV is also rescued by inhibition of the stimulator of interferon genes (STING), suggesting that pUL46-mediated suppression of GJIC contributes to intercellular virus spread by hindering intercellular communication that activates STING. The current study identifies key viral and cellular proteins involved in alphaherpesvirus-mediated suppression of GJIC and reveals that GJIC inhibition enhances virus intercellular spread, thereby opening new avenues for the design of targeted antiviral therapies.
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Affiliation(s)
- Alexander Tishchenko
- Department of Translational Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Nicolás Romero
- Department of Translational Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Cliff Van Waesberghe
- Department of Translational Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Jonas L. Delva
- Department of Translational Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Oliver Vickman
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Gregory A. Smith
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Thomas C. Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institute, Insel Riems, Germany
| | - Walter Fuchs
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institute, Insel Riems, Germany
| | - Barbara G. Klupp
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institute, Insel Riems, Germany
| | - Herman W. Favoreel
- Department of Translational Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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4
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Latchford LP, Perez LS, Conage-Pough JE, Turk R, Cusimano MA, Vargas VI, Arora S, Shienvold SR, Kulp RR, Belverio HM, White FM, Thévenin AF. Differential substrate specificity of ERK, JNK, and p38 MAP kinases toward Connexin 43. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.30.573692. [PMID: 38234737 PMCID: PMC10793482 DOI: 10.1101/2023.12.30.573692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Phosphorylation of connexin 43 (Cx43) is an important regulatory mechanism of gap junction (GJ) function. Cx43 is modified by several kinases on over 15 sites within its ~140 amino acid-long C terminus (CT). Phosphorylation of Cx43CT on S255, S262, S279, and S282 by ERK has been widely documented in several cell lines, by many investigators. Phosphorylation of these sites by JNK and p38, on the other hand, is not well-established. Indeed, ERK is a kinase activated by growth factors and is upregulated in diseases, such as cancer. JNK and p38, however, have a largely tumor-suppressive function due to their stress-activated and apoptotic role. We investigated substrate specificity of all three MAPKs toward Cx43CT, first by using purified proteins, and then in two cell lines (MDCK: non-cancerous, epithelial cells and porcine PAECs: pulmonary artery endothelial cells). Cx43 phosphorylation was monitored through gel-shift assays on an SDS-PAGE, immunodetection with phospho-Cx43 antibodies, and LC-MS/MS phosphoproteomic analyses. Our results demonstrate that p38 and JNK specificity differ from each other and from ERK. JNK has a strong preference for S255, S262, and S279, while p38 readily phosphorylates S262, S279, and S282. While we confirmed that ERK can phosphorylate all four serines (255, 262, 279, and 282), we also identified T290 as a novel ERK phosphorylation site. In addition, we assessed Cx43 GJ function upon activation or inhibition of each MAPK in PAECs. This work underscores the importance of delineating the effects of ERK, JNK, and p38 signaling on Cx43 and GJ function.
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5
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Jiang H, Zhang M, Wang HQ, Zhang NN, Li XM, Yang XY, Chen AP, Yan X, Zhang Z, Chu SF, Wang ZZ, Chen NH. Inflammation and Connexin 43 profiles in the prefrontal cortex are relevant to stress susceptibility and resilience in mice. Pharmacol Biochem Behav 2024; 239:173757. [PMID: 38574898 DOI: 10.1016/j.pbb.2024.173757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/05/2024] [Accepted: 03/25/2024] [Indexed: 04/06/2024]
Abstract
Depression is a major chronic mental illness worldwide, characterized by anhedonia and pessimism. Exposed to the same stressful stimuli, some people behave normally, while others exhibit negative behaviors and psychology. The exact molecular mechanisms linking stress-induced depressive susceptibility and resilience remain unclear. Connexin 43 (Cx43) forms gap junction channels between the astrocytes, acting as a crucial role in the pathogenesis of depression. Cx43 dysfunction could lead to depressive behaviors, and depression down-regulates the expression of Cx43 in the prefrontal cortex (PFC). Besides, accumulating evidence indicates that inflammation is one of the most common pathological features of the central nervous system dysfunction. However, the roles of Cx43 and peripheral inflammation in stress-susceptible and stress-resilient individuals have rarely been investigated. Thus, animals were classified into the chronic unpredictable stress (CUS)-susceptible group and the CUS-resilient group based on the performance of behavioral tests following the CUS protocol in this study. The protein expression of Cx43 in the PFC, the Cx43 functional changes in the PFC, and the expression levels including interleukin (IL)-1β, tumor necrosis factor-α, IL-6, IL-2, IL-10, and IL-18 in the peripheral serum were detected. Here, we found that stress exposure triggered a significant reduction in Cx43 protein expression in the CUS-susceptible mice but not in the CUS-resilient mice accompanied by various Cx43 phosphorylation expression and the changes of inflammatory signals. Stress resilience is associated with Cx43 in the PFC and fluctuation in inflammatory signaling, showing that therapeutic targeting of these pathways might promote stress resilience.
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Affiliation(s)
- Hong Jiang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Meng Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Hui-Qin Wang
- School of Pharmacy, Hunan University of Traditional Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208, China
| | - Ning-Ning Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Xin-Mu Li
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Xue-Ying Yang
- School of Chinese Materia Medica, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Ai-Ping Chen
- China Three Gorges University College of Medicine and Health Sciences, Yichang 443002, China
| | - Xu Yan
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Zhao Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Shi-Feng Chu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; School of Pharmacy, Hunan University of Traditional Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208, China.
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6
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Papadakos SP, Chatzikalil E, Arvanitakis K, Vakadaris G, Stergiou IE, Koutsompina ML, Argyrou A, Lekakis V, Konstantinidis I, Germanidis G, Theocharis S. Understanding the Role of Connexins in Hepatocellular Carcinoma: Molecular and Prognostic Implications. Cancers (Basel) 2024; 16:1533. [PMID: 38672615 PMCID: PMC11048329 DOI: 10.3390/cancers16081533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
Connexins, a family of tetraspan membrane proteins forming intercellular channels localized in gap junctions, play a pivotal role at the different stages of tumor progression presenting both pro- and anti-tumorigenic effects. Considering the potential role of connexins as tumor suppressors through multiple channel-independent mechanisms, their loss of expression may be associated with tumorigenic activity, while it is hypothesized that connexins favor the clonal expansion of tumor cells and promote cell migration, invasion, and proliferation, affecting metastasis and chemoresistance in some cases. Hepatocellular carcinoma (HCC), characterized by unfavorable prognosis and limited responsiveness to current therapeutic strategies, has been linked to gap junction proteins as tumorigenic factors with prognostic value. Notably, several members of connexins have emerged as promising markers for assessing the progression and aggressiveness of HCC, as well as the chemosensitivity and radiosensitivity of hepatocellular tumor cells. Our review sheds light on the multifaceted role of connexins in HCC pathogenesis, offering valuable insights on recent advances in determining their prognostic and therapeutic potential.
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Affiliation(s)
- Stavros P. Papadakos
- First Department of Pathology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (S.P.P.); (E.C.)
| | - Elena Chatzikalil
- First Department of Pathology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (S.P.P.); (E.C.)
| | - Konstantinos Arvanitakis
- Division of Gastroenterology and Hepatology, First Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece; (K.A.); (G.V.)
- Basic and Translational Research Unit, Special Unit for Biomedical Research and Education, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece
| | - Georgios Vakadaris
- Division of Gastroenterology and Hepatology, First Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece; (K.A.); (G.V.)
| | - Ioanna E. Stergiou
- Pathophysiology Department, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece; (I.E.S.); (M.-L.K.)
| | - Maria-Loukia Koutsompina
- Pathophysiology Department, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece; (I.E.S.); (M.-L.K.)
| | - Alexandra Argyrou
- Academic Department of Gastroenterology, Laikon General Hospital, Athens University Medical School, 11527 Athens, Greece; (A.A.); (V.L.)
| | - Vasileios Lekakis
- Academic Department of Gastroenterology, Laikon General Hospital, Athens University Medical School, 11527 Athens, Greece; (A.A.); (V.L.)
| | | | - Georgios Germanidis
- Division of Gastroenterology and Hepatology, First Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece; (K.A.); (G.V.)
- Basic and Translational Research Unit, Special Unit for Biomedical Research and Education, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54636 Thessaloniki, Greece
| | - Stamatios Theocharis
- First Department of Pathology, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (S.P.P.); (E.C.)
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Martins-Marques T, Witschas K, Ribeiro I, Zuzarte M, Catarino S, Ribeiro-Rodrigues T, Caramelo F, Aasen T, Carreira IM, Goncalves L, Leybaert L, Girao H. Cx43 can form functional channels at the nuclear envelope and modulate gene expression in cardiac cells. Open Biol 2023; 13:230258. [PMID: 37907090 PMCID: PMC10645070 DOI: 10.1098/rsob.230258] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 09/12/2023] [Indexed: 11/02/2023] Open
Abstract
Classically associated with gap junction-mediated intercellular communication, connexin43 (Cx43) is increasingly recognized to possess non-canonical biological functions, including gene expression regulation. However, the mechanisms governing the localization and role played by Cx43 in the nucleus, namely in transcription modulation, remain unknown. Using comprehensive and complementary approaches encompassing biochemical assays, super-resolution and immunogold transmission electron microscopy, we demonstrate that Cx43 localizes to the nuclear envelope of different cell types and in cardiac tissue. We show that translocation of Cx43 to the nucleus relies on Importin-β, and that Cx43 significantly impacts the cellular transcriptome, likely by interacting with transcriptional regulators. In vitro patch-clamp recordings from HEK293 and adult primary cardiomyocytes demonstrate that Cx43 forms active channels at the nuclear envelope, providing evidence that Cx43 can participate in nucleocytoplasmic shuttling of small molecules. The accumulation of nuclear Cx43 during myogenic differentiation of cardiomyoblasts is suggested to modulate expression of genes implicated in this process. Altogether, our study provides new evidence for further defining the biological roles of nuclear Cx43, namely in cardiac pathophysiology.
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Affiliation(s)
- Tania Martins-Marques
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - Katja Witschas
- Department of Basic Medical Sciences – Physiology group, Ghent University, 9000 Ghent, Belgium
| | - Ilda Ribeiro
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Univ Coimbra, Cytogenetics and Genomics Laboratory (CIMAGO), Faculty of Medicine, 3004-531 Coimbra, Portugal
| | - Mónica Zuzarte
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - Steve Catarino
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - Teresa Ribeiro-Rodrigues
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - Francisco Caramelo
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Univ Coimbra, Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine, 3004-531 Coimbra, Portugal
| | - Trond Aasen
- Patologia Molecular Translacional, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain
- CIBER de Cáncer (CIBERONC), Instituto de Salud Carlos III, Avenida de Monforte de Lemos 3-5, 28029 Madrid, Spain
| | - Isabel Marques Carreira
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Univ Coimbra, Cytogenetics and Genomics Laboratory (CIMAGO), Faculty of Medicine, 3004-531 Coimbra, Portugal
| | - Lino Goncalves
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), 3004-561 Coimbra, Portugal
| | - Luc Leybaert
- Department of Basic Medical Sciences – Physiology group, Ghent University, 9000 Ghent, Belgium
| | - Henrique Girao
- Univ Coimbra, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, 3000-548 Coimbra, Portugal
- Univ Coimbra, Center for Innovative Biomedicine and Biotechnology (CIBB), 3004-504 Coimbra, Portugal
- Clinical Academic Centre of Coimbra (CACC), 3004-561 Coimbra, Portugal
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8
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Li T, Liu X, Ruan X, Dong W, Liu Y, Wang P, Liu L, Tiange E, Song J, Pan A, Xue Y. A novel peptide P1-121aa encoded by STK24P1 regulates vasculogenic mimicry via ELF2 phosphorylation in glioblastoma. Exp Neurol 2023; 367:114477. [PMID: 37406957 DOI: 10.1016/j.expneurol.2023.114477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/24/2023] [Accepted: 06/30/2023] [Indexed: 07/07/2023]
Abstract
Glioblastoma (GBM) is the most common malignant tumor of the central nervous system. Vasculogenic mimicry (VM) is a hematological system composed of tumor cells that exert blood perfusion without relying on vascular endothelial cells. The current poor results of anti-vascular therapy for clinical GBM are associated with the presence of VM; therefore, it is important to investigate VM formation in GBM. Our results demonstrate that STK24P1 encodes P1-121aa with a kinase structural domain, and in vitro kinase assays demonstrated that P1-121aa mediates modification of ELF2 phosphorylation. ChIP and dual luciferase reporter gene assays demonstrated that the transcription factor ELF2 binds to VE-cadherin and the VEGFR2 promoter region, thereby promoting VM formation in glioma cells. P1-121aa, encoded by the pseudogene STK24P1, phosphorylates ELF2 at S107, increasing the stability of the ELF2 protein. ELF2 promotes VEGFR2 and VE-cadherin expression at the transcriptional level, which in turn promotes VM in GBM. This study demonstrates the important roles of STK24P1, P1-121aa, and ELF2 in regulating VM in GBM, which could provide potential targets for GBM treatment.
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Affiliation(s)
- Tianyun Li
- Department of Neurobiology, School of life Sciences, China Medical University, Shenyang 110122, China; Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China
| | - Xiaobai Liu
- Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China; Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - XueLei Ruan
- Department of Neurobiology, School of life Sciences, China Medical University, Shenyang 110122, China; Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China
| | - Weiwei Dong
- Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China; Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - Yunhui Liu
- Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China; Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - Ping Wang
- Department of Neurobiology, School of life Sciences, China Medical University, Shenyang 110122, China; Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China
| | - Libo Liu
- Department of Neurobiology, School of life Sciences, China Medical University, Shenyang 110122, China; Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China
| | - E Tiange
- Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China; Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - Jian Song
- Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China; Department of Neurosurgery, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - Aini Pan
- Department of Neurobiology, School of life Sciences, China Medical University, Shenyang 110122, China; Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China
| | - Yixue Xue
- Department of Neurobiology, School of life Sciences, China Medical University, Shenyang 110122, China; Key Laboratory of Neuro-oncology in Liaoning Province, Shenyang 110004, China.
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9
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D'Amico D, Barone R, Di Felice V, Ances B, Prideaux B, Eugenin EA. Chronic brain damage in HIV-infected individuals under antiretroviral therapy is associated with viral reservoirs, sulfatide release, and compromised cell-to-cell communication. Cell Mol Life Sci 2023; 80:116. [PMID: 37016051 PMCID: PMC11071786 DOI: 10.1007/s00018-023-04757-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 03/11/2023] [Accepted: 03/13/2023] [Indexed: 04/06/2023]
Abstract
HIV infection has become a chronic and manageable disease due to the effective use of antiretroviral therapies (ART); however, several chronic aging-related comorbidities, including cognitive impairment, remain a major public health issue. However, these mechanisms are unknown. Here, we identified that glial and myeloid viral reservoirs are associated with local myelin damage and the release of several myelin components, including the lipid sulfatide. Soluble sulfatide compromised gap junctional communication and calcium wave coordination, essential for proper cognition. We propose that soluble sulfatide could be a potential biomarker and contributor to white matter compromise observed in HIV-infected individuals even in the current ART era.
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Affiliation(s)
- Daniela D'Amico
- Department of Neurobiology, The University of Texas Medical Branch (UTMB), Research Building 17, Fifth Floor, 11Th Street, Galveston, TX, 77555, USA
- Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Rosario Barone
- Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Valentina Di Felice
- Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Beau Ances
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Brendan Prideaux
- Department of Neurobiology, The University of Texas Medical Branch (UTMB), Research Building 17, Fifth Floor, 11Th Street, Galveston, TX, 77555, USA.
| | - Eliseo A Eugenin
- Department of Neurobiology, The University of Texas Medical Branch (UTMB), Research Building 17, Fifth Floor, 11Th Street, Galveston, TX, 77555, USA.
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10
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Zhou M, Zheng M, Zhou X, Tian S, Yang X, Ning Y, Li Y, Zhang S. The roles of connexins and gap junctions in the progression of cancer. Cell Commun Signal 2023; 21:8. [PMID: 36639804 PMCID: PMC9837928 DOI: 10.1186/s12964-022-01009-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/03/2022] [Indexed: 01/15/2023] Open
Abstract
Gap junctions (GJs), which are composed of connexins (Cxs), provide channels for direct information exchange between cells. Cx expression has a strong spatial specificity; however, its influence on cell behavior and information exchange between cells cannot be ignored. A variety of factors in organisms can modulate Cxs and subsequently trigger a series of responses that have important effects on cellular behavior. The expression and function of Cxs and the number and function of GJs are in dynamic change. Cxs have been characterized as tumor suppressors in the past, but recent studies have highlighted the critical roles of Cxs and GJs in cancer pathogenesis. The complex mechanism underlying Cx and GJ involvement in cancer development is a major obstacle to the evolution of therapy targeting Cxs. In this paper, we review the post-translational modifications of Cxs, the interactions of Cxs with several chaperone proteins, and the effects of Cxs and GJs on cancer. Video Abstract.
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Affiliation(s)
- Mingming Zhou
- Graduate School, Tianjin Medical University, Tianjin, 300070 People’s Republic of China
| | - Minying Zheng
- Department of Pathology, Tianjin Union Medical Center, Nankai University, Tianjin, 300121 People’s Republic of China
| | - Xinyue Zhou
- Graduate School, Tianjin Medical University, Tianjin, 300070 People’s Republic of China
| | - Shifeng Tian
- Graduate School, Tianjin Medical University, Tianjin, 300070 People’s Republic of China
| | - Xiaohui Yang
- Nankai University School of Medicine, Nankai University, Tianjin, 300071 People’s Republic of China
| | - Yidi Ning
- Nankai University School of Medicine, Nankai University, Tianjin, 300071 People’s Republic of China
| | - Yuwei Li
- Department of Colorectal Surgery, Tianjin Union Medical Center, Tianjin, 300121 People’s Republic of China
| | - Shiwu Zhang
- Department of Pathology, Tianjin Union Medical Center, Nankai University, Tianjin, 300121 People’s Republic of China
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11
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Pun R, Kim MH, North BJ. Role of Connexin 43 phosphorylation on Serine-368 by PKC in cardiac function and disease. Front Cardiovasc Med 2023; 9:1080131. [PMID: 36712244 PMCID: PMC9877470 DOI: 10.3389/fcvm.2022.1080131] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/19/2022] [Indexed: 01/13/2023] Open
Abstract
Intercellular communication mediated by gap junction channels and hemichannels composed of Connexin 43 (Cx43) is vital for the propagation of electrical impulses through cardiomyocytes. The carboxyl terminal tail of Cx43 undergoes various post-translational modifications including phosphorylation of its Serine-368 (S368) residue. Protein Kinase C isozymes directly phosphorylate S368 to alter Cx43 function and stability through inducing conformational changes affecting channel permeability or promoting internalization and degradation to reduce intercellular communication between cardiomyocytes. Recent studies have implicated this PKC/Cx43-pS368 circuit in several cardiac-associated diseases. In this review, we describe the molecular and cellular basis of PKC-mediated Cx43 phosphorylation and discuss the implications of Cx43 S368 phosphorylation in the context of various cardiac diseases, such as cardiomyopathy, as well as the therapeutic potential of targeting this pathway.
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Affiliation(s)
- Renju Pun
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States
| | - Michael H. Kim
- CHI Health Heart Institute, School of Medicine, Creighton University, Omaha, NE, United States
| | - Brian J. North
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States,*Correspondence: Brian J. North,
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12
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The Role of Connexin in Ophthalmic Neovascularization and the Interaction between Connexin and Proangiogenic Factors. J Ophthalmol 2022; 2022:8105229. [PMID: 35783340 PMCID: PMC9242797 DOI: 10.1155/2022/8105229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 06/11/2022] [Indexed: 12/02/2022] Open
Abstract
The formation of new blood vessels is an important physiological process that occurs during development. When the body is injured, new blood vessel formation helps the body recuperate by supplying more oxygen and nutrients. However, this mechanism can have a negative effect. In ophthalmologic diseases, such as corneal new blood vessels, neonatal vascular glaucoma, and diabetes retinopathy, the formation of new blood vessels has become a critical component in patient survival. Connexin is a protein that regulates the cellular and molecular material carried by cells. It has been demonstrated that it is widely expressed in vascular endothelial cells, where it forms a slit connection between adjacent cells to promote cell-cell communication via hemichannels, as well as substance exchange into intracellular environments. Numerous studies have demonstrated that connexin in vascular endothelial cells plays an important role in angiogenesis and vascular leakage. The purpose of this study was to investigate the effect between the angiogenesis-associated factor and the connexin. It also reveals the effect of connexin on ophthalmic neovascularization.
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13
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Laird DW, Lampe PD. Cellular mechanisms of connexin-based inherited diseases. Trends Cell Biol 2022; 32:58-69. [PMID: 34429228 PMCID: PMC8688313 DOI: 10.1016/j.tcb.2021.07.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 01/03/2023]
Abstract
The 21-member connexin gene family exhibits distinct tissue expression patterns that can cause a diverse array of over 30 inherited connexin-linked diseases ranging from deafness to skin defects and blindness. Intriguingly, germline mutations can cause disease in one tissue while other tissues that abundantly express the mutant connexin remain disease free, highlighting the importance of the cellular context of mutant expression. Modeling connexin pathologies in genetically modified mice and tissue-relevant cells has informed extensively on no less than a dozen gain- and loss-of-function mechanisms that underpin disease. This review focuses on how a deeper molecular understanding of the over 930 mutations in 11 connexin-encoding genes is foundational for creating a framework for therapeutic interventions.
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Affiliation(s)
- Dale W. Laird
- Departments of Anatomy and Cell Biology, and Physiology and Pharmacology, University of Western Ontario, London, ON, CANADA
| | - Paul D. Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
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14
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Beckmann A, Recktenwald J, Ferdinand A, Grißmer A, Meier C. First Responders to Hyperosmotic Stress in Murine Astrocytes: Connexin 43 Gap Junctions Are Subject to an Immediate Ultrastructural Reorganization. BIOLOGY 2021; 10:biology10121307. [PMID: 34943223 PMCID: PMC8698406 DOI: 10.3390/biology10121307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/04/2021] [Accepted: 12/06/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Gap junctions are intercellular channels that provide the means for direct transport of small molecules, ions, and water between connected cells. With these functions, gap junctions are essential for the maintenance of astrocytic homeostasis and of particular importance in the context of pathophysiological disbalances. These include the hyperosmolar hyperglycemic syndrome or the pathology after brain trauma. We demonstrate that short-term hyperosmolarity reduces intercellular communication via gap junctions. These functional changes coincide with the transformation of gap junction ultrastructure as evidenced by freeze-fracture replica immunolabeling and transmission electron microscopy. The hyperosmolarity-induced immediate changes in the ultrastructural assembly of connexons, the protein constituents of gap junction channels, have not been described in astrocytes before and are revealing the coherence of structure and function in gap junctions. Phosphorylation of Connexin 43, the main gap junction protein in astrocytes, at amino acid 368 (Serine) might link the two. Abstract In a short-term model of hyperosmotic stress, primary murine astrocytes were stimulated with a hyperosmolar sucrose solution for five minutes. Astrocytic gap junctions, which are mainly composed of Connexin (Cx) 43, displayed immediate ultrastructural changes, demonstrated by freeze–fracture replica immunogold labeling: their area, perimeter, and distance of intramembrane particles increased, whereas particle numbers per area decreased. Ultrastructural changes were, however, not accompanied by changes in Cx43 mRNA expression. In contrast, transcription of the gap junction regulator zonula occludens (ZO) protein 1 significantly increased, whereas its protein expression was unaffected. Phosphorylation of Serine (S) 368 of the Cx43 C–terminus has previously been associated with gap junction disassembly and reduction in gap junction communication. Hyperosmolar sucrose treatment led to enhanced phosphorylation of Cx43S368 and was accompanied by inhibition of gap junctional intercellular communication, demonstrated by a scrape loading-dye transfer assay. Taken together, Cx43 gap junctions are fast reacting elements in response to hyperosmolar challenges and can therefore be considered as one of the first responders to hyperosmolarity. In this process, phosphorylation of Cx43S368 was associated with disassembly of gap junctions and inhibition of their function. Thus, modulation of the gap junction assembly might represent a target in the treatment of brain edema or trauma.
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15
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King DR, Sedovy MW, Leng X, Xue J, Lamouille S, Koval M, Isakson BE, Johnstone SR. Mechanisms of Connexin Regulating Peptides. Int J Mol Sci 2021; 22:ijms221910186. [PMID: 34638526 PMCID: PMC8507914 DOI: 10.3390/ijms221910186] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 12/22/2022] Open
Abstract
Gap junctions (GJ) and connexins play integral roles in cellular physiology and have been found to be involved in multiple pathophysiological states from cancer to cardiovascular disease. Studies over the last 60 years have demonstrated the utility of altering GJ signaling pathways in experimental models, which has led to them being attractive targets for therapeutic intervention. A number of different mechanisms have been proposed to regulate GJ signaling, including channel blocking, enhancing channel open state, and disrupting protein-protein interactions. The primary mechanism for this has been through the design of numerous peptides as therapeutics, that are either currently in early development or are in various stages of clinical trials. Despite over 25 years of research into connexin targeting peptides, the overall mechanisms of action are still poorly understood. In this overview, we discuss published connexin targeting peptides, their reported mechanisms of action, and the potential for these molecules in the treatment of disease.
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Affiliation(s)
- D. Ryan King
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
| | - Meghan W. Sedovy
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
- Translational Biology, Medicine, and Health Graduate Program, Virginia Tech, Blacksburg, VA 24061, USA
| | - Xinyan Leng
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
| | - Jianxiang Xue
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (J.X.); (B.E.I.)
| | - Samy Lamouille
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
- Center for Vascular and Heart Research, Virginia Tech, Roanoke, VA 24016, USA
| | - Michael Koval
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA;
| | - Brant E. Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; (J.X.); (B.E.I.)
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Scott R. Johnstone
- Fralin Biomedical Research Institute at Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, VA 24016, USA; (D.R.K.); (M.W.S.); (X.L.); (S.L.)
- Center for Vascular and Heart Research, Virginia Tech, Roanoke, VA 24016, USA
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24060, USA
- Correspondence:
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16
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Montgomery J, Richardson WJ, Marsh S, Rhett JM, Bustos F, Degen K, Ghatnekar GS, Grek CL, Jourdan LJ, Holmes JW, Gourdie RG. The connexin 43 carboxyl terminal mimetic peptide αCT1 prompts differentiation of a collagen scar matrix in humans resembling unwounded skin. FASEB J 2021; 35:e21762. [PMID: 34246197 DOI: 10.1096/fj.202001881r] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 06/02/2021] [Accepted: 06/14/2021] [Indexed: 12/12/2022]
Abstract
Phase II clinical trials have reported that acute treatment of surgical skin wounds with the therapeutic peptide alpha Connexin Carboxy-Terminus 1 (αCT1) improves cutaneous scar appearance by 47% 9-month postsurgery. While Cx43 and ZO-1 have been identified as molecular targets of αCT1, the mode-of-action of the peptide in scar mitigation at cellular and tissue levels remains to be further characterized. Scar histoarchitecture in αCT1 and vehicle-control treated skin wounds within the same patient were compared using biopsies from a Phase I clinical trial at 29-day postwounding. The sole effect on scar structure of a range of epidermal and dermal variables examined was that αCT1-treated scars had less alignment of collagen fibers relative to control wounds-a characteristic that resembles unwounded skin. The with-in subject effect of αCT1 on scar collagen order observed in Phase I testing in humans was recapitulated in Sprague-Dawley rats and the IAF hairless guinea pig. Transient increase in histologic collagen density in response to αCT1 was also observed in both animal models. Mouse NIH 3T3 fibroblasts and primary human dermal fibroblasts treated with αCT1 in vitro showed more rapid closure in scratch wound assays, with individual cells showing decreased directionality in movement. An agent-based computational model parameterized with fibroblast motility data predicted collagen alignments in simulated scars consistent with that observed experimentally in human and the animal models. In conclusion, αCT1 prompts decreased directionality of fibroblast movement and the generation of a 3D collagen matrix postwounding that is similar to unwounded skin-changes that correlate with long-term improvement in scar appearance.
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Affiliation(s)
- Jade Montgomery
- Fralin Biomedical Research Institute, Center for Vascular and Heart Research, Virginia Tech Carilion, Roanoke, VA, USA.,Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA
| | | | - Spencer Marsh
- Fralin Biomedical Research Institute, Center for Vascular and Heart Research, Virginia Tech Carilion, Roanoke, VA, USA
| | - J Matthew Rhett
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA
| | - Francis Bustos
- Fralin Biomedical Research Institute, Center for Vascular and Heart Research, Virginia Tech Carilion, Roanoke, VA, USA.,Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
| | - Katherine Degen
- Fralin Biomedical Research Institute, Center for Vascular and Heart Research, Virginia Tech Carilion, Roanoke, VA, USA.,Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA
| | | | | | - L Jane Jourdan
- Fralin Biomedical Research Institute, Center for Vascular and Heart Research, Virginia Tech Carilion, Roanoke, VA, USA
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
| | - Robert G Gourdie
- Fralin Biomedical Research Institute, Center for Vascular and Heart Research, Virginia Tech Carilion, Roanoke, VA, USA.,Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA, USA.,Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
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17
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Liu Y, Chu S, Hu Y, Yang S, Li X, Zheng Q, Ai Q, Ren S, Wang H, Gong L, Xu X, Chen NH. Exogenous Adenosine Antagonizes Excitatory Amino Acid Toxicity in Primary Astrocytes. Cell Mol Neurobiol 2021; 41:687-704. [PMID: 32632892 PMCID: PMC11448567 DOI: 10.1007/s10571-020-00876-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 05/12/2020] [Indexed: 12/29/2022]
Abstract
Excitatory toxicity is still a hot topic in the study of ischemic stroke, and related research has focused mainly on neurons. Adenosine is an important neuromodulator that is known as a "biosignature" in the central nervous system (CNS). The protective effect of exogenous adenosine on neurons has been confirmed, but its mechanism remains elusive. In this study, astrocytes were pretreated with adenosine, and the effects of an A2a receptor (A2aR) inhibitor (SCH58261) and A2b receptor (A2bR) inhibitor (PSB1115) on excitatory glutamate were investigated. An oxygen glucose deprivation/reoxygenation (OGD/R) and glutamate model was generated in vitro. Post-model assessment included expression levels of glutamate transporters (glt-1), gap junction protein (Cx43) and glutamate receptor (AMPAR), Na+-K+-ATPase activity, and diffusion distance of dyes. Glutamate and glutamine contents were determined at different time points. The results showed that (1) adenosine could improve the function of Na+-K+-ATPase, upregulate the expression of glt-1, and enhance the synthesis of glutamine in astrocytes. This effect was associated with A2aR activation but not with A2bR activation. (2) Adenosine could inhibit the expression of gap junction protein (Cx43) and reduce glutamate diffusion. Inhibition of A2aR attenuated adenosine inhibition of gap junction intercellular communication (GJIC) in the OGD/R model, while it enhanced adenosine inhibition of GJIC in the glutamate model, depending on the glutamate concentration. (3) Adenosine could cause AMPAR gradually entered the nucleus from the cytoplasm, thereby reducing the expression of AMPAR on the cell membrane. Taken together, the results indicate that adenosine plays a role of anti-excitatory toxicity effect in protection against neuronal death and the functional recovery of ischemic stroke mainly by targeting astrocytes, which are closely related to A2aR. The present study provided a scientific basis for adenosine prevention and ischemic stroke treatment, thereby providing a new approach for alleviating ischemic stroke.
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Affiliation(s)
- Yingjiao Liu
- College of Pharmacy, Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha, 410208, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Shifeng Chu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Yaomei Hu
- College of Pharmacy, Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha, 410208, China
| | - Songwei Yang
- College of Pharmacy, Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha, 410208, China
| | - Xun Li
- College of Pharmacy, Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha, 410208, China
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Qinglian Zheng
- Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China
| | - Qidi Ai
- College of Pharmacy, Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha, 410208, China
| | - Siyu Ren
- College of Pharmacy, Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha, 410208, China
| | - Huiqin Wang
- College of Pharmacy, Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha, 410208, China
| | - Limin Gong
- College of Pharmacy, Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha, 410208, China
| | - Xin Xu
- Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China
| | - Nai-Hong Chen
- College of Pharmacy, Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha, 410208, China.
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
- Institute for Brain Research and Rehabilitation, South China Normal University, Guangzhou, 510631, China.
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18
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Lasseigne AM, Echeverry FA, Ijaz S, Michel JC, Martin EA, Marsh AJ, Trujillo E, Marsden KC, Pereda AE, Miller AC. Electrical synaptic transmission requires a postsynaptic scaffolding protein. eLife 2021; 10:e66898. [PMID: 33908867 PMCID: PMC8081524 DOI: 10.7554/elife.66898] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/30/2021] [Indexed: 02/06/2023] Open
Abstract
Electrical synaptic transmission relies on neuronal gap junctions containing channels constructed by Connexins. While at chemical synapses neurotransmitter-gated ion channels are critically supported by scaffolding proteins, it is unknown if channels at electrical synapses require similar scaffold support. Here, we investigated the functional relationship between neuronal Connexins and Zonula Occludens 1 (ZO1), an intracellular scaffolding protein localized to electrical synapses. Using model electrical synapses in zebrafish Mauthner cells, we demonstrated that ZO1 is required for robust synaptic Connexin localization, but Connexins are dispensable for ZO1 localization. Disrupting this hierarchical ZO1/Connexin relationship abolishes electrical transmission and disrupts Mauthner cell-initiated escape responses. We found that ZO1 is asymmetrically localized exclusively postsynaptically at neuronal contacts where it functions to assemble intercellular channels. Thus, forming functional neuronal gap junctions requires a postsynaptic scaffolding protein. The critical function of a scaffolding molecule reveals an unanticipated complexity of molecular and functional organization at electrical synapses.
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Affiliation(s)
| | - Fabio A Echeverry
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineBronxUnited States
| | - Sundas Ijaz
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineBronxUnited States
| | | | - E Anne Martin
- Institute of Neuroscience, University of OregonEugeneUnited States
| | - Audrey J Marsh
- Institute of Neuroscience, University of OregonEugeneUnited States
| | - Elisa Trujillo
- Institute of Neuroscience, University of OregonEugeneUnited States
| | - Kurt C Marsden
- Department of Biological Sciences, NC State UniversityRaleighUnited States
| | - Alberto E Pereda
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of MedicineBronxUnited States
| | - Adam C Miller
- Institute of Neuroscience, University of OregonEugeneUnited States
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19
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Connexins and cAMP Cross-Talk in Cancer Progression and Metastasis. Cancers (Basel) 2020; 13:cancers13010058. [PMID: 33379194 PMCID: PMC7795795 DOI: 10.3390/cancers13010058] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/21/2020] [Accepted: 12/21/2020] [Indexed: 02/06/2023] Open
Abstract
Simple Summary Different connexins play diverse roles in cancers, either tumor-suppressing or tumor-promoting. In lung cancer, Cx43 serves as a tumor suppressor at the early stage, but it can also be a tumor-promotor at an advanced stage and during metastasis. Moreover, other connexins, including Cx26, Cx31.1, and Cx32, can be tumor suppressors. In contrast, Cx30.3 can be a tumor-promotor. The roles of different connexins in different cancers have also been established. Cx43 acts as a tumor suppressor in colorectal cancer, breast cancer, and glioma, whereas Cx32 can be a suppressor in liver tumors and hepatocarcinogenesis. Cx26 can be a tumor suppressor in mammary tumors; in contrast, it can be a tumor-promotor in melanoma. Existing drugs/molecules targeting the cAMP/PKA/connexin axis act to regulate channel opening/closing. Mimic peptides, such as Gap19, Gap26, and Gap 27 block hemichannels, mimetic peptides, and CT9/CT10 and promote hemichannel opening and also hemichannel closing. Abstract Connexin-containing gap junctions mediate the direct exchange of small molecules between cells, thus promoting cell–cell communication. Connexins (Cxs) have been widely studied as key tumor-suppressors. However, certain Cx subtypes, such as Cx43 and Cx26, are overexpressed in metastatic tumor lesions. Cyclic adenosine monophosphate (cAMP) signaling regulates Cx expression and function via transcriptional control and phosphorylation. cAMP also passes through gap junction channels between adjacent cells, regulating cell cycle progression, particularly in cancer cell populations. Low levels of cAMP are sufficient to activate key effectors. The present review evaluates the mechanisms underlying Cx regulation by cAMP signaling and the role of gap junctions in cancer progression and metastasis. A deeper understanding of these processes might facilitate the development of novel anticancer drugs.
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Strauss RE, Gourdie RG. Cx43 and the Actin Cytoskeleton: Novel Roles and Implications for Cell-Cell Junction-Based Barrier Function Regulation. Biomolecules 2020; 10:E1656. [PMID: 33321985 PMCID: PMC7764618 DOI: 10.3390/biom10121656] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/07/2020] [Accepted: 12/07/2020] [Indexed: 12/13/2022] Open
Abstract
Barrier function is a vital homeostatic mechanism employed by epithelial and endothelial tissue. Diseases across a wide range of tissue types involve dynamic changes in transcellular junctional complexes and the actin cytoskeleton in the regulation of substance exchange across tissue compartments. In this review, we focus on the contribution of the gap junction protein, Cx43, to the biophysical and biochemical regulation of barrier function. First, we introduce the structure and canonical channel-dependent functions of Cx43. Second, we define barrier function and examine the key molecular structures fundamental to its regulation. Third, we survey the literature on the channel-dependent roles of connexins in barrier function, with an emphasis on the role of Cx43 and the actin cytoskeleton. Lastly, we discuss findings on the channel-independent roles of Cx43 in its associations with the actin cytoskeleton and focal adhesion structures highlighted by PI3K signaling, in the potential modulation of cellular barriers. Mounting evidence of crosstalk between connexins, the cytoskeleton, focal adhesion complexes, and junctional structures has led to a growing appreciation of how barrier-modulating mechanisms may work together to effect solute and cellular flux across tissue boundaries. This new understanding could translate into improved therapeutic outcomes in the treatment of barrier-associated diseases.
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Affiliation(s)
- Randy E. Strauss
- Virginia Tech, Translational Biology Medicine and Health (TBMH) Program, Roanoke, VA 24016, USA
| | - Robert G. Gourdie
- Center for Heart and Reparative Medicine Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
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Solan JL, Lampe PD. Src Regulation of Cx43 Phosphorylation and Gap Junction Turnover. Biomolecules 2020; 10:biom10121596. [PMID: 33255329 PMCID: PMC7759836 DOI: 10.3390/biom10121596] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/19/2020] [Accepted: 11/22/2020] [Indexed: 12/18/2022] Open
Abstract
The gap junction protein Connexin43 (Cx43) is highly regulated by phosphorylation at over a dozen sites by probably at least as many kinases. This Cx43 “kinome” plays an important role in gap junction assembly and turnover. We sought to gain a better understanding of the interrelationship of these phosphorylation events particularly related to src activation and Cx43 turnover. Using state-of-the-art live imaging methods, specific inhibitors and many phosphorylation-status specific antibodies, we found phospho-specific domains in gap junction plaques and show evidence that multiple pathways of disassembly exist and can be regulated at the cellular and subcellular level. We found Src activation promotes formation of connexisomes (internalized gap junctions) in a process involving ERK-mediated phosphorylation of S279/282. Proteasome inhibition dramatically and rapidly restored gap junctions in the presence of Src and led to dramatic changes in the Cx43 phospho-profile including to increased Y247, Y265, S279/282, S365, and S373 phosphorylation. Lysosomal inhibition, on the other hand, nearly eliminated phosphorylation on Y247 and Y265 and reduced S368 and S373 while increasing S279/282 phosphorylation levels. We present a model of gap junction disassembly where multiple modes of disassembly are regulated by phosphorylation and can have differential effects on cellular signaling.
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Affiliation(s)
- Joell L. Solan
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
| | - Paul D. Lampe
- Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
- Department of Global Health, Pathobiology Program, University of Washington, Seattle, WA 98109, USA
- Correspondence:
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Tetenborg S, Wang HY, Nemitz L, Depping A, Espejo AB, Aseervatham J, Bedford MT, Janssen-Bienhold U, O'Brien J, Dedek K. Phosphorylation of Connexin36 near the C-terminus switches binding affinities for PDZ-domain and 14-3-3 proteins in vitro. Sci Rep 2020; 10:18378. [PMID: 33110101 PMCID: PMC7592057 DOI: 10.1038/s41598-020-75375-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 10/12/2020] [Indexed: 12/20/2022] Open
Abstract
Connexin36 (Cx36) is the most abundant connexin in central nervous system neurons. It forms gap junction channels that act as electrical synapses. Similar to chemical synapses, Cx36-containing gap junctions undergo activity-dependent plasticity and complex regulation. Cx36 gap junctions represent multimolecular complexes and contain cytoskeletal, regulatory and scaffolding proteins, which regulate channel conductance, assembly and turnover. The amino acid sequence of mammalian Cx36 harbors a phosphorylation site for the Ca2+/calmodulin-dependent kinase II at serine 315. This regulatory site is homologous to the serine 298 in perch Cx35 and in close vicinity to a PDZ binding domain at the very C-terminal end of the protein. We hypothesized that this phosphorylation site may serve as a molecular switch, influencing the affinity of the PDZ binding domain for its binding partners. Protein microarray and pulldown experiments revealed that this is indeed the case: phosphorylation of serine 298 decreased the binding affinity for MUPP1, a known scaffolding partner of connexin36, and increased the binding affinity for two different 14-3-3 proteins. Although we did not find the same effect in cell culture experiments, our data suggest that phosphorylation of serine 315/298 may serve to recruit different proteins to connexin36/35-containing gap junctions in an activity-dependent manner.
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Affiliation(s)
- Stephan Tetenborg
- Animal Navigation/Neurosensorics, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
- Ruiz Department of Ophthalmology & Visual Science, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Helen Y Wang
- Ruiz Department of Ophthalmology & Visual Science, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Lena Nemitz
- Visual Neuroscience, Dept. of Neuroscience, University of Oldenburg, Oldenburg, Germany
| | - Anne Depping
- Animal Navigation/Neurosensorics, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
| | - Alexsandra B Espejo
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, TX, 78957, USA
| | - Jaya Aseervatham
- Ruiz Department of Ophthalmology & Visual Science, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Mark T Bedford
- Department of Epigenetics and Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, TX, 78957, USA
| | - Ulrike Janssen-Bienhold
- Visual Neuroscience, Dept. of Neuroscience, University of Oldenburg, Oldenburg, Germany
- Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany
| | - John O'Brien
- Ruiz Department of Ophthalmology & Visual Science, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Karin Dedek
- Animal Navigation/Neurosensorics, Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany.
- Research Center Neurosensory Science, University of Oldenburg, Oldenburg, Germany.
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McCutcheon S, Stout RF, Spray DC. The dynamic Nexus: gap junctions control protein localization and mobility in distinct and surprising ways. Sci Rep 2020; 10:17011. [PMID: 33046777 PMCID: PMC7550573 DOI: 10.1038/s41598-020-73892-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 09/23/2020] [Indexed: 12/24/2022] Open
Abstract
Gap junction (GJ) channels permit molecules, such as ions, metabolites and second messengers, to transfer between cells. Their function is critical for numerous cellular interactions, providing exchange of metabolites, signaling molecules, and ionic currents. GJ channels are composed of Connexin (Cx) hexamers paired across extracellular space and typically form large rafts of clustered channels, called plaques, at cell appositions. Cxs together with molecules that interact with GJ channels make up a supramolecular structure known as the GJ Nexus. While the stability of connexin localization in GJ plaques has been studied, mobility of other Nexus components has yet to be addressed. Colocalization analysis of several nexus components and other membrane proteins reveal that certain molecules are excluded from the GJ plaque (Aquaporin 4, EAAT2b), while others are quite penetrant (lipophilic molecules, Cx30, ZO-1, Occludin). Fluorescence recovery after photobleaching of tagged Nexus-associated proteins showed that mobility in plaque domains is affected by mobility of the Cx proteins. These novel findings indicate that the GJ Nexus is a dynamic membrane organelle, with cytoplasmic and membrane-embedded proteins binding and diffusing according to distinct parameters.
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Affiliation(s)
- Sean McCutcheon
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, 10461, USA.
| | - Randy F Stout
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, 10461, USA.,Department of Biomedical Sciences, The New York Institute of Technology College of Osteopathic Medicine, 101 Northern Blvd., Old Westbury, NY, 11586, USA
| | - David C Spray
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY, 10461, USA
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Abstract
Of the 21 members of the connexin family, 4 (Cx37, Cx40, Cx43, and Cx45) are expressed in the endothelium and/or smooth muscle of intact blood vessels to a variable and dynamically regulated degree. Full-length connexins oligomerize and form channel structures connecting the cytosol of adjacent cells (gap junctions) or the cytosol with the extracellular space (hemichannels). The different connexins vary mainly with regard to length and sequence of their cytosolic COOH-terminal tails. These COOH-terminal parts, which in the case of Cx43 are also translated as independent short isoforms, are involved in various cellular signaling cascades and regulate cell functions. This review focuses on channel-dependent and -independent effects of connexins in vascular cells. Channels play an essential role in coordinating and synchronizing endothelial and smooth muscle activity and in their interplay, in the control of vasomotor actions of blood vessels including endothelial cell reactivity to agonist stimulation, nitric oxide-dependent dilation, and endothelial-derived hyperpolarizing factor-type responses. Further channel-dependent and -independent roles of connexins in blood vessel function range from basic processes of vascular remodeling and angiogenesis to vascular permeability and interactions with leukocytes with the vessel wall. Together, these connexin functions constitute an often underestimated basis for the enormous plasticity of vascular morphology and function enabling the required dynamic adaptation of the vascular system to varying tissue demands.
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Affiliation(s)
- Ulrich Pohl
- Walter-Brendel-Centre of Experimental Medicine, University Hospital, LMU Munich, Planegg-Martinsried, Germany; Biomedical Centre, Cardiovascular Physiology, LMU Munich, Planegg-Martinsried, Germany; German Centre for Cardiovascular Research, Partner Site Munich Heart Alliance, Munich, Germany; and Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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25
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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: 3.6] [Reference Citation Analysis] [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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Lagos-Cabré R, Burgos-Bravo F, Avalos AM, Leyton L. Connexins in Astrocyte Migration. Front Pharmacol 2020; 10:1546. [PMID: 32009957 PMCID: PMC6974553 DOI: 10.3389/fphar.2019.01546] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/29/2019] [Indexed: 12/18/2022] Open
Abstract
Astrocytes have long been considered the supportive cells of the central nervous system, but during the last decades, they have gained much more attention because of their active participation in the modulation of neuronal function. For example, after brain damage, astrocytes become reactive and undergo characteristic morphological and molecular changes, such as hypertrophy and increase in the expression of glial fibrillary acidic protein (GFAP), in a process known as astrogliosis. After severe damage, astrocytes migrate to the lesion site and proliferate, which leads to the formation of a glial scar. At this scar-forming stage, astrocytes secrete many factors, such as extracellular matrix proteins, cytokines, growth factors and chondroitin sulfate proteoglycans, stop migrating, and the process is irreversible. Although reactive gliosis is a normal physiological response that can protect brain cells from further damage, it also has detrimental effects on neuronal survival, by creating a hostile and non-permissive environment for axonal repair. The transformation of astrocytes from reactive to scar-forming astrocytes highlights migration as a relevant regulator of glial scar formation, and further emphasizes the importance of efficient communication between astrocytes in order to orchestrate cell migration. The coordination between astrocytes occurs mainly through Connexin (Cx) channels, in the form of direct cell-cell contact (gap junctions, GJs) or contact between the extracellular matrix and the astrocytes (hemichannels, HCs). Reactive astrocytes increase the expression levels of several proteins involved in astrocyte migration, such as αvβ3 Integrin, Syndecan-4 proteoglycan, the purinergic receptor P2X7, Pannexin1, and Cx43 HCs. Evidence has indicated that Cx43 HCs play a role in regulating astrocyte migration through the release of small molecules to the extracellular space, which then activate receptors in the same or adjacent cells to continue the signaling cascades required for astrocyte migration. In this review, we describe the communication of astrocytes through Cxs, the role of Cxs in inflammation and astrocyte migration, and discuss the molecular mechanisms that regulate Cx43 HCs, which may provide a therapeutic window of opportunity to control astrogliosis and the progression of neurodegenerative diseases.
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Affiliation(s)
- Raúl Lagos-Cabré
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Francesca Burgos-Bravo
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
| | - Ana María Avalos
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Lisette Leyton
- Cellular Communication Laboratory, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Center for Studies on Exercise, Metabolism and Cancer (CEMC), Facultad de Medicina, Instituto de Ciencias Biomédicas (ICBM), Universidad de Chile, Santiago, Chile
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Cohen-Barak E, Godsel LM, Koetsier JL, Hegazy M, Kushnir-Grinbaum D, Hammad H, Danial-Farran N, Harmon R, Khayat M, Bochner R, Peled A, Rozenblat M, Krausz J, Sarig O, Johnson JL, Ziv M, Shalev SA, Sprecher E, Green KJ. The Role of Desmoglein 1 in Gap Junction Turnover Revealed through the Study of SAM Syndrome. J Invest Dermatol 2019; 140:556-567.e9. [PMID: 31465738 DOI: 10.1016/j.jid.2019.08.433] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/15/2019] [Accepted: 08/02/2019] [Indexed: 11/18/2022]
Abstract
An effective epidermal barrier requires structural and functional integration of adherens junctions, tight junctions, gap junctions (GJ), and desmosomes. Desmosomes govern epidermal integrity while GJs facilitate small molecule transfer across cell membranes. Some patients with severe dermatitis, multiple allergies, and metabolic wasting (SAM) syndrome, caused by biallelic desmoglein 1 (DSG1) mutations, exhibit skin lesions reminiscent of erythrokeratodermia variabilis, caused by mutations in connexin (Cx) genes. We, therefore, examined whether SAM syndrome-causing DSG1 mutations interfere with Cx expression and GJ function. Lesional skin biopsies from SAM syndrome patients (n = 7) revealed decreased Dsg1 and Cx43 plasma membrane localization compared with control and nonlesional skin. Cultured keratinocytes and organotypic skin equivalents depleted of Dsg1 exhibited reduced Cx43 expression, rescued upon re-introduction of wild-type Dsg1, but not Dsg1 constructs modeling SAM syndrome-causing mutations. Ectopic Dsg1 expression increased cell-cell dye transfer, which Cx43 silencing inhibited, suggesting that Dsg1 promotes GJ function through Cx43. As GJA1 gene expression was not decreased upon Dsg1 loss, we hypothesized that Cx43 reduction was due to enhanced protein degradation. Supporting this, PKC-dependent Cx43 S368 phosphorylation, which signals Cx43 turnover, increased after Dsg1 depletion, while lysosomal inhibition restored Cx43 levels. These data reveal a role for Dsg1 in regulating epidermal Cx43 turnover.
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Affiliation(s)
- Eran Cohen-Barak
- Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Department of Dermatology, "Emek" Medical Center, Afula, Israel; Bruce and Ruth Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Lisa M Godsel
- Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Jennifer L Koetsier
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Marihan Hegazy
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | | | - Helwe Hammad
- Department of Dermatology, "Emek" Medical Center, Afula, Israel
| | | | - Robert Harmon
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Morad Khayat
- The Genetic Institute, "Emek" Medical Center, Afula, Israel
| | - Ron Bochner
- Department of Dermatology, Tel Aviv Medical Center, Tel Aviv, Israel
| | - Alon Peled
- Department of Dermatology, Tel Aviv Medical Center, Tel Aviv, Israel; Department of Human Molecular Genetics & Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Mati Rozenblat
- Department of Dermatology, "Emek" Medical Center, Afula, Israel
| | - Judit Krausz
- Department of Pathology, "Emek" Medical Center, Afula, Israel
| | - Ofer Sarig
- Department of Dermatology, Tel Aviv Medical Center, Tel Aviv, Israel
| | - Jodi L Johnson
- Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Michael Ziv
- Department of Dermatology, "Emek" Medical Center, Afula, Israel
| | - Stavit A Shalev
- Bruce and Ruth Rappaport Faculty of Medicine, Technion, Haifa, Israel; The Genetic Institute, "Emek" Medical Center, Afula, Israel
| | - Eli Sprecher
- Department of Dermatology, Tel Aviv Medical Center, Tel Aviv, Israel; Department of Human Molecular Genetics & Biochemistry, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Kathleen J Green
- Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL, USA.
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Jiang J, Hoagland D, Palatinus JA, He H, Iyyathurai J, Jourdan LJ, Bultynck G, Wang Z, Zhang Z, Schey K, Poelzing S, McGowan FX, Gourdie RG. Interaction of α Carboxyl Terminus 1 Peptide With the Connexin 43 Carboxyl Terminus Preserves Left Ventricular Function After Ischemia-Reperfusion Injury. J Am Heart Assoc 2019; 8:e012385. [PMID: 31422747 PMCID: PMC6759879 DOI: 10.1161/jaha.119.012385] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Background α Carboxyl terminus 1 (αCT1) is a 25–amino acid therapeutic peptide incorporating the zonula occludens‐1 (ZO‐1)–binding domain of connexin 43 (Cx43) that is currently in phase 3 clinical testing on chronic wounds. In mice, we reported that αCT1 reduced arrhythmias after cardiac injury, accompanied by increases in protein kinase Cε phosphorylation of Cx43 at serine 368. Herein, we characterize detailed molecular mode of action of αCT1 in mitigating cardiac ischemia‐reperfusion injury. Methods and Results To study αCT1‐mediated increases in phosphorylation of Cx43 at serine 368, we undertook mass spectrometry of protein kinase Cε phosphorylation assay reactants. This indicated potential interaction between negatively charged residues in the αCT1 Asp‐Asp‐Leu‐Glu‐Iso sequence and lysines (Lys345, Lys346) in an α‐helical sequence (helix 2) within the Cx43‐CT. In silico modeling provided further support for this interaction, indicating that αCT1 may interact with both Cx43 and ZO‐1. Using surface plasmon resonance, thermal shift, and phosphorylation assays, we characterized a series of αCT1 variants, identifying peptides that interacted with either ZO‐1–postsynaptic density‐95/disks large/zonula occludens‐1 2 or Cx43‐CT, but with limited or no ability to bind both molecules. Only peptides competent to interact with Cx43‐CT, but not ZO‐1–postsynaptic density‐95/disks large/zonula occludens‐1 2 alone, prompted increased pS368 phosphorylation. Moreover, in an ex vivo mouse model of ischemia‐reperfusion injury, preischemic infusion only with those peptides competent to bind Cx43 preserved ventricular function after ischemia‐reperfusion. Interestingly, a short 9–amino acid variant of αCT1 (αCT11) demonstrated potent cardioprotective effects when infused either before or after ischemic injury. Conclusions Interaction of αCT1 with the Cx43, but not ZO‐1, is correlated with cardioprotection. Pharmacophores targeting Cx43‐CT could provide a translational approach to preserving heart function after ischemic injury.
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Affiliation(s)
- Jingbo Jiang
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA.,Shenzhen Children's Hospital Shenzhen China.,Department of Pediatric Cardiology Guangdong Cardiovascular Institute Guangdong General Hospital Guangdong Academy of Medical Sciences Guangzhou China
| | - Daniel Hoagland
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA
| | - Joseph A Palatinus
- Cedars-Sinai Heart Smidt Institute Cedars-Sinai Medical Center Los Angeles CA
| | - Huamei He
- Department of Anesthesiology and Critical Care Medicine Children's Hospital of Philadelphia and University of Pennsylvania Philadelphia PA
| | - Jegan Iyyathurai
- Department Cellular and Molecular Medicine KU Leuven Laboratory of Molecular and Cellular Signaling Leuven Belgium
| | - L Jane Jourdan
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA
| | - Geert Bultynck
- Department Cellular and Molecular Medicine KU Leuven Laboratory of Molecular and Cellular Signaling Leuven Belgium
| | - Zhen Wang
- Department of Biochemistry Vanderbilt University School of Medicine Nashville TN
| | - Zhiwei Zhang
- Department of Pediatric Cardiology Guangdong Cardiovascular Institute Guangdong General Hospital Guangdong Academy of Medical Sciences Guangzhou China
| | - Kevin Schey
- Department of Biochemistry Vanderbilt University School of Medicine Nashville TN
| | - Steven Poelzing
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA.,Department of Biomedical Engineering and Mechanics Virginia Tech Blacksburg VA
| | - Francis X McGowan
- Department of Anesthesiology and Critical Care Medicine Children's Hospital of Philadelphia and University of Pennsylvania Philadelphia PA
| | - Robert G Gourdie
- Fralin Biomedical Research Institute at Virginia Tech Carilion Center for Heart and Reparative Medicine Research Virginia Tech Blacksburg VA.,Department of Biomedical Engineering and Mechanics Virginia Tech Blacksburg VA
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29
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Propofol attenuates monocyte-endothelial adhesion via modulating connexin43 expression in monocytes. Life Sci 2019; 232:116624. [PMID: 31276689 DOI: 10.1016/j.lfs.2019.116624] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 06/22/2019] [Accepted: 06/30/2019] [Indexed: 02/07/2023]
Abstract
AIMS Monocyte-endothelial adhesion is considered to be the primary initiator of inflammatory vascular diseases, such as atherosclerosis. Connexin 43 (Cx43) has been reported to play an important part in this process, however, the underlying mechanisms are not fully understood. Intravenous anesthetics, propofol is commonly used in the perioperative period and in the intensive care unit, and considered to have good anti-inflammatory and antioxidant effects. Thus, we speculate that propofol could influence monocyte-endothelial adhesion, and explore whether its possible mechanism is relative with Cx43 expression in U937 monocytes influencing cell adhesion of U937 monocytes to human umbilical vein endothelial cells (HUVEC). MAIN METHODS Cx43-siRNAs or pc-DNA-Cx43 were used to alter Cx43 expression in U937 monocytes. Propofol was given as pretreatments to U937 monocytes. Then, cell adhesion, ZO-1, LFA-1, VLA-4, COX and MCP-1 were determined. PI3K/AKT/NF-κB signaling pathway was explored to clarify the possible mechanism. KEY FINDINGS Alternation of Cx43 expression affects cell adhesion and adhesion molecules significantly, such as ZO-1, LFA-1, VLA-4, COX-2 and MCP-1, the mechanism of which is relative with Cx43 influencing the activation of PI3K/AKT/NF-κB signaling pathway. Preconditioning with propofol at its clinically relevant anesthesia concentration attenuates cell adhesion. Propofol not only decreases Cx43 expression in U937 monocytes, but also depresses the activation of PI3K/AKT/NF-κB signaling pathway. SIGNIFICANCE Modulation Cx43 expression in U937 monocytes could affect cell adhesion via regulating the activation of PI3K/AKT/NF-κB signaling pathway. Propofol attenuates cell adhesion via inhibiting Cx43 and its downstream signaling pathway of PI3K/AKT/NF-κB.
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30
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Sun Z, Yang Y, Wu L, Talabieke S, You H, Zheng Y, Luo D. Connexin 43-serine 282 modulates serine 279 phosphorylation in cardiomyocytes. Biochem Biophys Res Commun 2019; 513:567-572. [PMID: 30981509 DOI: 10.1016/j.bbrc.2019.04.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 04/03/2019] [Indexed: 12/21/2022]
Abstract
Connexin 43 (Cx43) phosphorylation plays a pivotal role in cardiac electrical and contractile performance. In a previous study we have found that Cx43 phosphorylation at serine 282 (pS282) regulates cardiomyocyte survival. Considering that both sites are altered simultaneously in many studies, we designed this study to identify the status of S279 phosphorylation upon pS282 manipulation. In heterozygous mice with S282 gene substituted with alanine (S282A), we found ventricular arrhythmias with inhibition of Cx43 phosphorylation at both S282 and S279 in the hearts. In cultured neonatal rat ventricular myocytes (NRVMs), transfection of virus carrying S282A mutant also blocked Cx43 phosphorylation at both S279/282 and gap junction coupling, while expression of wild-type Cx43 or S279A did not. Further, NRVMs transfected with S282 phospho-mimicking mutant substituted with aspartate or treated with ATP exhibited promotions of Cx43 phosphorylation at S279/282 and intercellular communication. Therefore, this study demonstrated a regulatory role of Cx43-S282 on S279 phosphorylation in cardiomyocytes, and suggested an involvement of S279 in the Cx43-S282 mediated cardiomyocyte homeostasis.
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Affiliation(s)
- Zhipeng Sun
- Department of Pharmacology, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, PR China
| | - Yutong Yang
- Department of Pharmacology, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, PR China
| | - Lulin Wu
- Department of Pharmacology, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, PR China
| | - Shaletanati Talabieke
- Department of Pharmacology, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, PR China
| | - Hongjie You
- Department of Pharmacology, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, PR China
| | - Yuanyuan Zheng
- Department of Pharmacology, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, PR China
| | - Dali Luo
- Department of Pharmacology, Beijing Key Laboratory of Metabolic Disturbance Related Cardiovascular Disease, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, PR China.
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31
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Pogoda K, Kameritsch P, Mannell H, Pohl U. Connexins in the control of vasomotor function. Acta Physiol (Oxf) 2019; 225:e13108. [PMID: 29858558 DOI: 10.1111/apha.13108] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 12/13/2022]
Abstract
Vascular endothelial cells, as well as smooth muscle cells, show heterogeneity with regard to their receptor expression and reactivity. For the vascular wall to act as a functional unit, the various cells' responses require integration. Such an integration is not only required for a homogeneous response of the vascular wall, but also for the vasomotor behaviour of consecutive segments of the microvascular arteriolar tree. As flow resistances of individual sections are connected in series, sections require synchronization and coordination to allow effective changes of conductivity and blood flow. A prerequisite for the local coordination of individual vascular cells and different sections of an arteriolar tree is intercellular communication. Connexins are involved in a dual manner in this coordination. (i) By forming gap junctions between cells, they allow an intercellular exchange of signalling molecules and electrical currents. In particular, the spread of electrical currents allows for coordination of cell responses over longer distances. (ii) Connexins are able to interact with other proteins to form signalling complexes. In this way, they can modulate and integrate individual cells' responses also in a channel-independent manner. This review outlines mechanisms allowing the vascular connexins to exert their coordinating function and to regulate the vasomotor reactions of blood vessels both locally, and in vascular networks. Wherever possible, we focus on the vasomotor behaviour of small vessels and arterioles which are the main vessels determining vascular resistance, blood pressure and local blood flow.
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Affiliation(s)
- K. Pogoda
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - P. Kameritsch
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
| | - H. Mannell
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
| | - U. Pohl
- Walter-Brendel-Centre of Experimental Medicine; University Hospital; LMU Munich; Munich Germany
- Biomedical Center; Cardiovascular Physiology; LMU Munich; Munich Germany
- DZHK (German Center for Cardiovascular Research); Partner Site Munich Heart Alliance; Munich Germany
- Munich Cluster for Systems Neurology (SyNergy); Munich Germany
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32
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Gourdie RG. The Cardiac Gap Junction has Discrete Functions in Electrotonic and Ephaptic Coupling. Anat Rec (Hoboken) 2018; 302:93-100. [PMID: 30565418 DOI: 10.1002/ar.24036] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 07/10/2018] [Accepted: 07/17/2018] [Indexed: 12/31/2022]
Abstract
Connexin43-formed gap junctions have long been thought to contribute to cardiac conduction in the mammalian ventricle by providing direct electrotonic connectivity between the cytoplasms of neighboring cardiomyocytes. However, accumulating data from studies of non-mammalian hearts, Connexin 43 (Cx43) knockout mice and human Cx43 mutations have raised questions as to whether gap junctions are the sole means by which electrical coupling between cardiomyocytes is accomplished. Computational and experimental work over the last decade have indicated that intercellular propagation of action potentials in the heart may involve both electrotonic and ephaptic contributions-in what has been dubbed "mixed-mode" conduction. Interestingly, the Cx43 gap junction may provide a common structural platform in mammals that facilitates the operation of these two mechanisms. In addition to gap junction channels functioning in an electrotonic role, the perinexus region at the edge of gap junctions may be provide a niche for voltage-gated sodium channels from neighboring cells to be in sufficiently close proximity to enable ephaptic transmission of action potential. A novel role has recently been identified in this potential ephaptic mechanism for inter-membrane adhesion mediated by the beta subunit (beta1/Scn1b) of the sodium channel. The new perspective of the operational redundancy that is built into cardiac electrical connectivity could provide new understanding of arrhythmia mechanisms and holds the promise for new approach to anti-arrhythmic therapy. Anat Rec, 302:93-100, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Robert G Gourdie
- Center for Heart and Regenerative Medicine, Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia, 24016.,Department of Emergency Medicine, Virginia Tech Carilion School of Medicine, Virginia Tech, Roanoke, Virginia, 24016.,Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, Virginia, 24061
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33
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Beckmann A, Grißmer A, Wolf S, Recktenwald J, Meier C. Oxygen-Glucose Deprivation in Mouse Astrocytes is Associated with Ultrastructural Changes in Connexin 43 Gap Junctions. Neuroscience 2018; 397:67-79. [PMID: 30513376 DOI: 10.1016/j.neuroscience.2018.11.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/26/2018] [Accepted: 11/28/2018] [Indexed: 01/09/2023]
Abstract
In the intact brain, astrocytes play an important role in a number of physiological functions like spatial buffering of potassium, maintenance of calcium homeostasis, neurotransmitter release, regulation of the cerebral blood flow, and many more. As pathophysiological events upon hypoxic-ischemic brain injury include excitotoxicity by glutamate release as well as oxidative stress, astrocytes and their gap junction-based syncytium are of major relevance for regulating the extent of resulting brain damage. The gap junction protein Connexin (Cx) 43 contributes mainly to the astrocytic intercellular communication. As little is known about the ultrastructural assemblage of Cx43 and its changes in response to hypoxic events, we chose temporary oxygen and glucose deprivation with subsequent reoxygenation (OGD-R) as a metabolic inhibition model of hypoxia in primary murine astrocytes. Gap junction morphology and assembly/disintegration were analyzed at the ultrastructural level using freeze-fracture replica immunolabeling. The exposure of cultured astrocytes to short-term OGD-R resulted in the activation of ERK1/2 (p44/p42), downregulation of Cx43 protein expression, and the rearrangement of Cx43 particles within the cell membrane and within gap junctions. These changes in gap junction morphology were associated with phosphorylation of Cx43 at Serine 368. Analysis of the nearest-neighbor distance within gap junction plaques revealed the loosening of Cx43 particle clusters. Together with the observation of additional connexons being present in the vicinity of gap junction plaques after OGD-R treatment, our study indicates that changes in gap junction assembly are associated with the early phase of hypoxic cell damage.
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Affiliation(s)
- Anja Beckmann
- Department of Anatomy and Cell Biology, Saarland University, 66421 Homburg, Saar, Germany
| | - Alexander Grißmer
- Department of Anatomy and Cell Biology, Saarland University, 66421 Homburg, Saar, Germany
| | - Sandra Wolf
- Department of Anatomy and Cell Biology, Saarland University, 66421 Homburg, Saar, Germany
| | - Johanna Recktenwald
- Department of Anatomy and Cell Biology, Saarland University, 66421 Homburg, Saar, Germany
| | - Carola Meier
- Department of Anatomy and Cell Biology, Saarland University, 66421 Homburg, Saar, Germany.
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34
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Kells-Andrews RM, Margraf RA, Fisher CG, Falk MM. Connexin-43 K63-polyubiquitylation on lysines 264 and 303 regulates gap junction internalization. J Cell Sci 2018; 131:jcs.204321. [PMID: 30054380 DOI: 10.1242/jcs.204321] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 06/22/2018] [Indexed: 12/20/2022] Open
Abstract
Gap junctions (GJs) assembled from connexin (Cx) proteins allow direct cell-cell communication. While phosphorylation is known to regulate multiple GJ functions, much less is known about the role of ubiquitin in these processes. Using ubiquitylation-type-specific antibodies and Cx43 lysine-to-arginine mutants we show that ∼8% of a GJ, localized in central plaque domains, is K63-polyubiquitylated on K264 and K303. Levels and localization of ubiquitylation correlated well with: (1) the short turnover rate of Cxs and GJs; (2) removal of older channels from the plaque center; and (3) the fact that not all Cxs in an internalizing GJ channel need to be ubiquitylated. Connexins mutated at these two sites assembled significantly larger GJs, exhibited much longer protein half-lives and were internalization impaired. Interestingly, these ubiquitin-deficient Cx43 mutants accumulated as hyper-phosphorylated polypeptides in the plasma membrane, suggesting that K63-polyubiquitylation is triggered by phosphorylation. Phospho-specific anti-Cx43 antibodies revealed that upregulated phosphorylation affected serines 368, 279/282 and 255, which are well-known regulatory PKC and MAPK sites. Together, these novel findings suggest that the internalizing portion of channels in a GJ is K63-polyubiquitylated, ubiquitylation is critical for GJ internalization and that phosphorylation induces Cx K63-polyubiquitylation.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Rachael M Kells-Andrews
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA
| | - Rachel A Margraf
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA
| | - Charles G Fisher
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA
| | - Matthias M Falk
- Department of Biological Sciences, Lehigh University, 111 Research Drive, Iacocca Hall, Bethlehem, PA 18015, USA
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35
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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: 2.4] [Reference Citation Analysis] [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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36
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Sorgen PL, Trease AJ, Spagnol G, Delmar M, Nielsen MS. Protein⁻Protein Interactions with Connexin 43: Regulation and Function. Int J Mol Sci 2018; 19:E1428. [PMID: 29748463 PMCID: PMC5983787 DOI: 10.3390/ijms19051428] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 12/11/2022] Open
Abstract
Connexins are integral membrane building blocks that form gap junctions, enabling direct cytoplasmic exchange of ions and low-molecular-mass metabolites between adjacent cells. In the heart, gap junctions mediate the propagation of cardiac action potentials and the maintenance of a regular beating rhythm. A number of connexin interacting proteins have been described and are known gap junction regulators either through direct effects (e.g., kinases) or the formation of larger multifunctional complexes (e.g., cytoskeleton scaffold proteins). Most connexin partners can be categorized as either proteins promoting coupling by stimulating forward trafficking and channel opening or inhibiting coupling by inducing channel closure, internalization, and degradation. While some interactions have only been implied through co-localization using immunohistochemistry, others have been confirmed by biophysical methods that allow detection of a direct interaction. Our understanding of these interactions is, by far, most well developed for connexin 43 (Cx43) and the scope of this review is to summarize our current knowledge of their functional and regulatory roles. The significance of these interactions is further exemplified by demonstrating their importance at the intercalated disc, a major hub for Cx43 regulation and Cx43 mediated effects.
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Affiliation(s)
- Paul L Sorgen
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Andrew J Trease
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Gaelle Spagnol
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA.
| | - Mario Delmar
- Leon H Charney Division of Cardiology, NYU School of Medicine, New York, NY 10016, USA.
| | - Morten S Nielsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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37
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Aasen T, Johnstone S, Vidal-Brime L, Lynn KS, Koval M. Connexins: Synthesis, Post-Translational Modifications, and Trafficking in Health and Disease. Int J Mol Sci 2018; 19:ijms19051296. [PMID: 29701678 PMCID: PMC5983588 DOI: 10.3390/ijms19051296] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 02/06/2023] Open
Abstract
Connexins are tetraspan transmembrane proteins that form gap junctions and facilitate direct intercellular communication, a critical feature for the development, function, and homeostasis of tissues and organs. In addition, a growing number of gap junction-independent functions are being ascribed to these proteins. The connexin gene family is under extensive regulation at the transcriptional and post-transcriptional level, and undergoes numerous modifications at the protein level, including phosphorylation, which ultimately affects their trafficking, stability, and function. Here, we summarize these key regulatory events, with emphasis on how these affect connexin multifunctionality in health and disease.
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Affiliation(s)
- Trond Aasen
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
| | - Scott Johnstone
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, P.O. Box 801394, Charlottesville, VI 22908, USA.
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TT, UK.
| | - Laia Vidal-Brime
- Translational Molecular Pathology, Vall d'Hebron Institute of Research (VHIR), Autonomous University of Barcelona, CIBERONC, 08035 Barcelona, Spain.
| | - K Sabrina Lynn
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Michael Koval
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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