1
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Peng DW, Lai YY, Luo XS, Li X, Deng CY, Guo HM, Zhao JF, Yang H, Liu Y, Wang ZY, Xu YW, Kuang SJ, Wu SL, Xue YM, Rao F. Connexin 43 participates in atrial electrical remodelling through colocalization with calcium channels in atrial myocytes. Clin Exp Pharmacol Physiol 2021; 49:25-34. [PMID: 34438468 DOI: 10.1111/1440-1681.13580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/24/2021] [Indexed: 11/29/2022]
Abstract
Atrial fibrillation (AF) is associated with atrial conduction disturbances caused by electrical and/or structural remodelling. In the present study, we hypothesized that connexin might interact with the calcium channel through forming a protein complex and, then, participates in the pathogenesis of AF. Western blot and whole-cell patch clamp showed that protein levels of Cav1.2 and connexin 43 (Cx43) and basal ICa , L were decreased in AF subjects compared to sinus rhythm (SR) controls. In cultured atrium-derived myocytes (HL-1 cells), knocking-down of Cx43 or incubation with 30 mmol/L glycyrrhetinic acid significantly inhibited protein levels of Cav1.2 and Cav3.1 and the current density of ICa , L and ICa , T . Incubation with nifedipine or mibefradil decreased the protein level of Cx43 in HL-1 cells. Moreover, Cx43 was colocalized with Cav1.2 and Cav3.1 in atrial myocytes. Therefore, Cx43 might regulate the ICa , L and ICa , T through colocalization with calcium channel subunits in atrial myocytes, representing a potential pathogenic mechanism in AF.
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Affiliation(s)
- De-Wei Peng
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Ying-Yu Lai
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Xue-Shan Luo
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Xin Li
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Chun-Yu Deng
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Hui-Ming Guo
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Jun-Fei Zhao
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Hui Yang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Yang Liu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Zhao-Yu Wang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Yu-Wen Xu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Su-Juan Kuang
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Shu-Lin Wu
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Yu-Mei Xue
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
| | - Fang Rao
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.,Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangzhou, China
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2
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Zhang D, Zhang Y, Zhao C, Zhang W, Shao G, Zhang H. Effect of lysophosphatidic acid on the immune inflammatory response and the connexin 43 protein in myocardial infarction. Exp Ther Med 2016; 11:1617-1624. [PMID: 27168781 DOI: 10.3892/etm.2016.3132] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/09/2016] [Indexed: 12/16/2022] Open
Abstract
Lysophosphatidic acid (LPA) is an intermediate product of membrane phospholipid metabolism. Recently, LPA has gained attention for its involvement in the pathological processes of certain cardiovascular diseases. The aim of the present study was to clarify the association between the effect of LPA and the immune inflammatory response, and to investigate the effects of LPA on the protein expression levels of connexin 43 during myocardial infarction. Surface electrocardiograms of myocardial infarction rats and isolated rat heart tissue samples were obtained in order to determine the effect of LPA on the incidence of arrhythmia in rats that exhibited changes in immune status. The results demonstrated that the incidence of arrhythmia decreased when the rat immune systems were suppressed, and the incidence of arrhythmia increased when the rat immune systems were enhanced. The concentration levels of tumor necrosis factor (TNF)-α were determined by ELISA, and the results demonstrated that LPA induced T lymphocyte synthesis and TNF-α release. Using a patch-clamp technique, LPA was shown to increase the current amplitude of the voltage-dependent potassium channels (Kv) and calcium-activated potassium channels (KCa) in Jurkat T cells. The protein expression of connexin 43 (Cx43) was determined by immunohistochemical staining. The results indicated that LPA caused the degradation of Cx43 and decreased the expression of Cx43. This effect was associated with the immune status of the rats. There was a further decrease in Cx43 expression in the rats of the immune-enhanced group. To the best of our knowledge, these results provide the first evidence that LPA causes arrhythmia through the regulation of immune inflammatory cells and the decrease of Cx43 protein expression. The present study provided an experimental basis for the treatment of arrhythmia and may guide clinical care.
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Affiliation(s)
- Duoduo Zhang
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China; Department of Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Yan Zhang
- Department of Anesthesiology, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Chunyan Zhao
- Department of Physiology, Norman Bethune College of Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Wenjie Zhang
- Department of Physiology, Norman Bethune College of Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Guoguang Shao
- Department of Thoracic Surgery, The First Hospital of Jilin University, Changchun, Jilin 130021, P.R. China
| | - Hong Zhang
- Department of Physiology, Norman Bethune College of Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
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3
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Williams ES, Viswanathan MN. Current and emerging antiarrhythmic drug therapy for ventricular tachycardia. Cardiol Ther 2013; 2:27-46. [PMID: 25135287 PMCID: PMC4107437 DOI: 10.1007/s40119-013-0012-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Indexed: 12/14/2022] Open
Abstract
Ventricular arrhythmias, including ventricular fibrillation (VF) and sustained ventricular tachycardia (VT), are the principal causes of sudden cardiac death in patients with structural heart disease. While coronary artery disease is the predominant substrate associated with the development of VT, these arrhythmias are known to occur in a variety of disorders, including dilated cardiomyopathy, valvular and congenital heart disease, and cardiac ion channelopathies such as the long QT syndrome. In a minority of patients, VT occurs in the absence of structural heart disease. Despite the established mortality benefit of the implantable cardioverter defibrillator (ICD) in patients at risk of lethal arrhythmias, recurrent VT/VF events continue to be a source of morbidity and impaired quality of life in such patients. Antiarrhythmic therapy is indicated in select patients to treat symptomatic VT episodes, to reduce the incidence of ICD shocks, and potentially to improve quality of life and reduce hospitalizations related to cardiac arrhythmia. The primary adverse effects of antiarrhythmic medications are related to both cardiac and extracardiac toxicity, including the risk of proarrhythmia. Current drug therapy for ventricular arrhythmia has been limited by suboptimal efficacy in many patients, resulting in recurrent VT/VF events, and by drug toxicity or intolerance leading to discontinuation in a large percentage of patients. Amiodarone and sotalol are the principal agents used in the chronic treatment of VT. In addition, dronedarone and dofetilide, agents approved for the treatment of atrial fibrillation, and ranolazine, an antianginal agent, have been demonstrated to be protective against ventricular arrhythmia in small clinical studies. Finally, advances in basic electrophysiology have uncovered new molecular targets for the treatment of ventricular arrhythmia, and pharmacologic agents directed at these targets may emerge as promising VT treatments in the future. The roles of these current and emerging therapies for the treatment of VT in humans will be summarized in this review.
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Affiliation(s)
- Eric S Williams
- Division of Cardiology, University of Washington Medical Center, Seattle, WA, USA,
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4
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Iyyathurai J, D'hondt C, Wang N, De Bock M, Himpens B, Retamal MA, Stehberg J, Leybaert L, Bultynck G. Peptides and peptide-derived molecules targeting the intracellular domains of Cx43: gap junctions versus hemichannels. Neuropharmacology 2013; 75:491-505. [PMID: 23664811 DOI: 10.1016/j.neuropharm.2013.04.050] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 04/17/2013] [Accepted: 04/18/2013] [Indexed: 12/15/2022]
Abstract
About a decade ago, the molecular determinants controlling the opening and closing of Cx43 gap junction channels have been identified. Advanced biophysical approaches revealed a critical role for structural rearrangements in the cytoplasmic loop and dimerization of the C-terminal tail, resulting in binding of the C-terminal tail to the cytoplasmic loop and Cx43 gap junction channel closure during cellular acidosis. This has spurred the development of Cx43-mimetic peptides and peptidomimetics that interfere with these loop/tail interactions, thereby preventing the closure of Cx43 gap junctions, e.g. in the heart upon ischemia. Recently, we found that loop/tail interactions control Cx43-hemichannel activity but with an opposite effect. Binding of the C-terminal tail to the cytoplasmic loop is a requisite for the opening of Cx43 hemichannels in response to different stimuli, like decreased extracellular [Ca2+], increased intracellular [Ca2+], positive membrane potentials or ischemia. Strikingly, peptides that favor the open state of Cx43 gap junctions like the L2 peptide inhibit Cx43-hemichannel opening. These tools now provide unprecedented opportunities to selectively inhibit Cx43 hemichannels while maintaining Cx43 gap junction communication, impossible to achieve with siRNA or knockdown approaches both affecting gap junctions and hemichannels. These tools not only are very helpful to unravel the role of Cx43 hemichannels in complex biological systems, but also hold therapeutic potential to counteract excessive Cx43-hemichannel activity like in ischemia/reperfusion in the brain and the heart or to prevent Cx43 hemichannel-mediated gliotransmitter release in the basal amygdala during memory consolidation in response to emotional events. This article is part of the Special Issue Section entitled 'Current Pharmacology of Gap Junction Channels and Hemichannels'.
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Affiliation(s)
- Jegan Iyyathurai
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Catheleyne D'hondt
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Nan Wang
- Faculty of Medicine and Health Sciences, Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B-Rm 310), B-9000 Ghent, Belgium
| | - Marijke De Bock
- Faculty of Medicine and Health Sciences, Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B-Rm 310), B-9000 Ghent, Belgium
| | - Bernard Himpens
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Mauricio A Retamal
- Departamento de Fisiología, Facultad de Medicina, Clínica Alemana-Universidad del Desarrollo, Santiago, Chile
| | - Jimmy Stehberg
- Universidad Andres Bello, Laboratorio de Neurobiologia, Departamento de Ciencias Biologicas, Facultad de Ciencias Biologicas & Facultad de Medicina, Santiago, Chile; Universidad Andres Bello, Centro de Investigaciones Biomédicas, Santiago, Chile
| | - Luc Leybaert
- Faculty of Medicine and Health Sciences, Physiology Group, Department of Basic Medical Sciences, Ghent University, De Pintelaan 185 (Block B-Rm 310), B-9000 Ghent, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Campus Gasthuisberg O/N-I Bus 802, Herestraat 49, BE-3000 Leuven, Belgium.
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5
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Saffitz JE, Kléber AG. Gap junctions, slow conduction, and ventricular tachycardia after myocardial infarction. J Am Coll Cardiol 2012; 60:1111-3. [PMID: 22883635 DOI: 10.1016/j.jacc.2012.05.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 05/15/2012] [Indexed: 10/28/2022]
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6
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Patel SJ, Milwid JM, King KR, Bohr S, Iracheta A, Li M, Vitalo A, Parekkadan B, Jindal R, Yarmush ML. Gap junction inhibition prevents drug-induced liver toxicity and fulminant hepatic failure. Nat Biotechnol 2012; 30:179-83. [PMID: 22252509 PMCID: PMC3609650 DOI: 10.1038/nbt.2089] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 12/08/2011] [Indexed: 02/07/2023]
Abstract
Drug-induced liver injury (DILI) limits the development and application of many therapeutic compounds and presents major challenges to the pharmaceutical industry and clinical medicine. Acetaminophen-containing compounds are among the most frequently prescribed drugs and are also the most common cause of DILI. Here we describe a pharmacological strategy that targets gap junction communication to prevent amplification of fulminant hepatic failure and acetaminophen-induced hepatotoxicity. We demonstrate that connexin 32 (Cx32), a key hepatic gap junction protein, is an essential mediator of DILI by showing that mice deficient in Cx32 are protected against liver damage, acute inflammation and death caused by liver-toxic drugs. We identify a small-molecule inhibitor of Cx32 that protects against liver failure and death in wild-type mice when co-administered with known hepatotoxic drugs. These findings indicate that gap junction inhibition could provide a pharmaceutical strategy to limit DILI and improve drug safety.
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Affiliation(s)
- Suraj J Patel
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
- Harvard-MIT Division of Health Science and Technology, Harvard Medical School, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jack M Milwid
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
- Harvard-MIT Division of Health Science and Technology, Harvard Medical School, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kevin R King
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
| | - Stefan Bohr
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
| | - Arvin Iracheta
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
| | - Matthew Li
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
| | - Antonia Vitalo
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
| | - Biju Parekkadan
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
| | - Rohit Jindal
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
- Department of Biomedical Engineering, Rutgers University, Piscataway NJ 08854, USA
| | - Martin L Yarmush
- Center for Engineering in Medicine and the Department of Surgery, Massachusetts General Hospital, and the Shriners Burns Hospital, Boston, MA 02114, USA
- Harvard-MIT Division of Health Science and Technology, Harvard Medical School, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biomedical Engineering, Rutgers University, Piscataway NJ 08854, USA
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7
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Palatinus JA, Rhett JM, Gourdie RG. The connexin43 carboxyl terminus and cardiac gap junction organization. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1831-43. [PMID: 21856279 DOI: 10.1016/j.bbamem.2011.08.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 07/25/2011] [Accepted: 08/03/2011] [Indexed: 12/09/2022]
Abstract
The precise spatial order of gap junctions at intercalated disks in adult ventricular myocardium is thought vital for maintaining cardiac synchrony. Breakdown or remodeling of this order is a hallmark of arrhythmic disease of the heart. The principal component of gap junction channels between ventricular cardiomyocytes is connexin43 (Cx43). Protein-protein interactions and modifications of the carboxyl-terminus of Cx43 are key determinants of gap junction function, size, distribution and organization during normal development and in disease processes. Here, we review data on the role of proteins interacting with the Cx43 carboxyl-terminus in the regulation of cardiac gap junction organization, with particular emphasis on Zonula Occludens-1. The rapid progress in this area suggests that in coming years we are likely to develop a fuller understanding of the molecular mechanisms causing pathologic remodeling of gap junctions. With these advances come the promise of novel approach to the treatment of arrhythmia and the prevention of sudden cardiac death. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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Affiliation(s)
- Joseph A Palatinus
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA
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8
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Palatinus JA, Rhett JM, Gourdie RG. Enhanced PKCε mediated phosphorylation of connexin43 at serine 368 by a carboxyl-terminal mimetic peptide is dependent on injury. Channels (Austin) 2011; 5:236-40. [PMID: 21532342 DOI: 10.4161/chan.5.3.15834] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The gap junction (GJ) protein connexin (Cx43) is important for organized action potential propagation between mammalian cardiomyocytes. Disruption of the highly ordered distribution of Cx43 GJs is characteristic of cardiac tissue after ischemic injury. We recently demonstrated that epicardial administration of a peptide mimetic of the Cx43 carboxyl-terminus reduced pathologic remodeling of Cx43 GJs and protected against induced arrhythmias following ventricular injury. Treatment of injuries with the carboxyl-terminal peptide was associated with an increase in phosphorylation at serine 368 of the Cx43 carboxyl-terminus. Here, we report that Cx43 peptide treatment of uninjured hearts does not prompt a similar increase in phosphorylation. Moreover, we show that peptide treatment of undisturbed cultured HeLa cells expressing a Cx43 construct also exhibit no changes in Cx43 phosphorylation at serine 368. However, in parallel with the results in vivo, a trend of increasing phosphorylation at serine 368 was observed in Cx43-expressing HeLa cells following scratch wounding of cultured monolayers. These results suggest that peptide-enhanced phosphorylation of the Cx43 carboxyl-terminus is dependent on injury-mediated cellular responses.
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Affiliation(s)
- Joseph A Palatinus
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC, USA
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9
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O'Quinn MP, Palatinus JA, Harris BS, Hewett KW, Gourdie RG. A peptide mimetic of the connexin43 carboxyl terminus reduces gap junction remodeling and induced arrhythmia following ventricular injury. Circ Res 2011; 108:704-15. [PMID: 21273554 DOI: 10.1161/circresaha.110.235747] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Remodeling of connexin (Cx)43 gap junctions (GJs) is linked to ventricular arrhythmia. OBJECTIVES A peptide mimetic of the carboxyl terminal (CT) of Cx43, incorporating a postsynaptic density-95/disks-large/ZO-1 (PDZ)-binding domain, reduces Cx43/ZO-1 interaction and GJ size remodeling in vitro. Here, we determined: (1) whether the Cx43-CT mimetic αCT1 altered GJ remodeling following left ventricular (LV) injury in vivo; (2) whether αCT1 affected arrhythmic propensity; and (3) the mechanism of αCT1 effects on arrhythmogenicity and GJ remodeling. METHODS AND RESULTS A cryoinjury model generating a reproducible wound and injury border zone (IBZ) in the LV was used. Adherent methylcellulose patches formulated to locally release αCT1 (< 48 hours) were placed on cryoinjuries. Relative to controls, Cx43/ZO-1 colocalization in the IBZ was reduced by αCT1 by 24 hours after injury. Programmed electric stimulation ex vivo and optical mapping of voltage transients indicated that peptide-treated hearts showed reduced inducible arrhythmias and increased ventricular depolarization rates 7 to 9 days after injury. At 24 hours and 1 week after injury, αCT1-treated hearts maintained Cx43 in intercalated disks (IDs) in the IBZ, whereas by 1 week after injury, controls demonstrated Cx43 remodeling from IDs to lateralized distributions. Over a postinjury time course of 1 week, αCT1-treated IBZs showed increased Cx43 phosphorylation at serine368 (Cx43-pS368) relative to control tissues. In biochemical assays, αCT1 promoted phosphorylation of serine368 by protein kinase (PK)C-ε in a dose-dependent manner that was modulated by, but did not require ZO-1 PDZ2. CONCLUSIONS αCT1 increases Cx43-pS368 in vitro in a PKC-ε-dependent manner and in the IBZ in vivo acutely following ventricular injury. αCT1-mediated increase in Cx43-pS368 phosphorylation may contribute to reductions in inducible-arrhythmia following injury.
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Affiliation(s)
- Michael P O'Quinn
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, USA
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10
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Ravens U. Antiarrhythmic therapy in atrial fibrillation. Pharmacol Ther 2010; 128:129-45. [DOI: 10.1016/j.pharmthera.2010.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 06/11/2010] [Indexed: 12/19/2022]
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11
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Affiliation(s)
- Pamela K Mason
- Division of Cardiovascular Medicine, University of Virginia Health System, Charlottesville, VA 22908, USA
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12
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Dhein S, Hagen A, Jozwiak J, Dietze A, Garbade J, Barten M, Kostelka M, Mohr FW. Improving cardiac gap junction communication as a new antiarrhythmic mechanism: the action of antiarrhythmic peptides. Naunyn Schmiedebergs Arch Pharmacol 2009; 381:221-34. [PMID: 19943035 DOI: 10.1007/s00210-009-0473-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Accepted: 11/08/2009] [Indexed: 12/22/2022]
Abstract
Co-ordinated electrical activation of the heart is maintained by intercellular coupling of cardiomyocytes via gap junctional channels located in the intercalated disks. These channels consist of two hexameric hemichannels, docked to each other, provided by either of the adjacent cells. Thus, a complete gap junction channel is made from 12 protein subunits, the connexins. While 21 isoforms of connexins are presently known, cardiomyocytes typically are coupled by Cx43 (most abundant), Cx40 or Cx45. Some years ago, antiarrhythmic peptides were discovered and synthesised, which were shown to increase macroscopic gap junction conductance (electrical coupling) and enhance dye transfer (metabolic coupling). The lead substance of these peptides is AAP10 (H-Gly-Ala-Gly-Hyp-Pro-Tyr-CONH(2)), a peptide with a horseshoe-like spatial structure as became evident from two-dimensional nuclear magnetic resonance studies. A stable D: -amino-acid derivative of AAP10, rotigaptide, as well as a non-peptide analogue, gap-134, has been developed in recent years. Antiarrhythmic peptides act on Cx43 and Cx45 gap junctions but not on Cx40 channels. AAP10 has been shown to enhance intercellular communication in rat, rabbit and human cardiomyocytes. Antiarrhythmic peptides are effective against ventricular tachyarrhythmias, such as late ischaemic (type IB) ventricular fibrillation, CaCl(2) or aconitine-induced arrhythmia. Interestingly, the effect of antiarrhythmic peptides is higher in partially uncoupled cells and was shown to be related to maintained Cx43 phosphorylation, while arrhythmogenic conditions like ischaemia result in Cx43 dephosphorylation and intercellular decoupling. It is still a matter of debate whether these drugs also act against atrial fibrillation. The present review outlines the development of this group of peptides and derivatives, their mode of action and molecular mechanisms, and discusses their possible therapeutic potential.
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Affiliation(s)
- Stefan Dhein
- Clinic for Cardiac Surgery, University of Leipzig, Struempellstr. 39, 04289, Leipzig, Germany.
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