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Bode D, Pronto JRD, Schiattarella GG, Voigt N. Metabolic remodelling in atrial fibrillation: manifestations, mechanisms and clinical implications. Nat Rev Cardiol 2024:10.1038/s41569-024-01038-6. [PMID: 38816507 DOI: 10.1038/s41569-024-01038-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/22/2024] [Indexed: 06/01/2024]
Abstract
Atrial fibrillation (AF) is a continually growing health-care burden that often presents together with metabolic disorders, including diabetes mellitus and obesity. Current treatments often fall short of preventing AF and its adverse outcomes. Accumulating evidence suggests that metabolic disturbances can promote the development of AF through structural and electrophysiological remodelling, but the underlying mechanisms that predispose an individual to AF are aetiology-dependent, thus emphasizing the need for tailored therapeutic strategies to treat AF that target an individual's metabolic profile. AF itself can induce changes in glucose, lipid and ketone metabolism, mitochondrial function and myofibrillar energetics (as part of a process referred to as 'metabolic remodelling'), which can all contribute to atrial dysfunction. In this Review, we discuss our current understanding of AF in the setting of metabolic disorders, as well as changes in atrial metabolism that are relevant to the development of AF. We also describe the potential of available and emerging treatment strategies to target metabolic remodelling in the setting of AF and highlight key questions and challenges that need to be addressed to improve outcomes in these patients.
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Affiliation(s)
- David Bode
- Max Rubner Center for Cardiovascular Metabolic Renal Research (MRC), Deutsches Herzzentrum der Charité (DHZC), Charité - Universitätsmedizin Berlin, Berlin, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
| | - Julius Ryan D Pronto
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Gabriele G Schiattarella
- Max Rubner Center for Cardiovascular Metabolic Renal Research (MRC), Deutsches Herzzentrum der Charité (DHZC), Charité - Universitätsmedizin Berlin, Berlin, Germany.
- DZHK (German Center for Cardiovascular Research), Partner Site Berlin, Berlin, Germany.
- Translational Approaches in Heart Failure and Cardiometabolic Disease, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany.
- Division of Cardiology, Department of Advanced Biomedical Sciences, Federico II University, Naples, Italy.
| | - Niels Voigt
- Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Göttingen, Germany.
- DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.
- Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany.
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2
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Xu J, Zhang D, Ma Y, Du H, Wang Y, Luo W, Wang R, Yi F. ROS in diabetic atria regulate SK2 degradation by Atrogin-1 through the NF-κB signaling pathway. J Biol Chem 2024; 300:105735. [PMID: 38336298 PMCID: PMC10938124 DOI: 10.1016/j.jbc.2024.105735] [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: 06/23/2023] [Revised: 01/13/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024] Open
Abstract
One of the independent risk factors for atrial fibrillation is diabetes mellitus (DM); however, the underlying mechanisms causing atrial fibrillation in DM are unknown. The underlying mechanism of Atrogin-1-mediated SK2 degradation and associated signaling pathways are unclear. The aim of this study was to elucidate the relationship among reactive oxygen species (ROS), the NF-κB signaling pathway, and Atrogin-1 protein expression in the atrial myocardia of DM mice. We found that SK2 expression was downregulated comitant with increased ROS generation and enhanced NF-κB signaling activation in the atrial cardiomyocytes of DM mice. These observations were mimicked by exogenously applicating H2O2 and by high glucose culture conditions in HL-1 cells. Inhibition of ROS production by diphenyleneiodonium chloride or silencing of NF-κB by siRNA decreased the protein expression of NF-κB and Atrogin-1 and increased that of SK2 in HL-1 cells with high glucose culture. Moreover, chromatin immunoprecipitation assay demonstrated that NF-κB/p65 directly binds to the promoter of the FBXO32 gene (encoding Atrogin-1), regulating the FBXO32 transcription. Finally, we evaluated the therapeutic effects of curcumin, known as a NF-κB inhibitor, on Atrogin-1 and SK2 expression in DM mice and confirmed that oral administration of curcumin for 4 weeks significantly suppressed Atrogin-1 expression and protected SK2 expression against hyperglycemia. In summary, the results from this study indicated that the ROS/NF-κB signaling pathway participates in Atrogin-1-mediated SK2 regulation in the atria of streptozotocin-induced DM mice.
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Affiliation(s)
- Jian Xu
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China; Senior Department of Cardiology, The Sixth Medical Center of PLA General Hospital, Beijing, China
| | - Dong Zhang
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yibo Ma
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Hui Du
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yi Wang
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Wenping Luo
- Institute of Cardiovascular and Vascular Disease, Shaanxi University of Traditional Chinese Medicine, Xianyang, China
| | - Ruxing Wang
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu, China
| | - Fu Yi
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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3
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Herrera NT, Zhang X, Ni H, Maleckar MM, Heijman J, Dobrev D, Grandi E, Morotti S. Dual effects of the small-conductance Ca 2+-activated K + current on human atrial electrophysiology and Ca 2+-driven arrhythmogenesis: an in silico study. Am J Physiol Heart Circ Physiol 2023; 325:H896-H908. [PMID: 37624096 PMCID: PMC10659325 DOI: 10.1152/ajpheart.00362.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/11/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023]
Abstract
By sensing changes in intracellular Ca2+, small-conductance Ca2+-activated K+ (SK) channels dynamically regulate the dynamics of the cardiac action potential (AP) on a beat-to-beat basis. Given their predominance in atria versus ventricles, SK channels are considered a promising atrial-selective pharmacological target against atrial fibrillation (AF), the most common cardiac arrhythmia. However, the precise contribution of SK current (ISK) to atrial arrhythmogenesis is poorly understood, and may potentially involve different mechanisms that depend on species, heart rates, and degree of AF-induced atrial remodeling. Both reduced and enhanced ISK have been linked to AF. Similarly, both SK channel up- and downregulation have been reported in chronic AF (cAF) versus normal sinus rhythm (nSR) patient samples. Here, we use our multiscale modeling framework to obtain mechanistic insights into the contribution of ISK in human atrial cardiomyocyte electrophysiology. We simulate several protocols to quantify how ISK modulation affects the regulation of AP duration (APD), Ca2+ transient, refractoriness, and occurrence of alternans and delayed afterdepolarizations (DADs). Our simulations show that ISK activation shortens the APD and atrial effective refractory period, limits Ca2+ cycling, and slightly increases the propensity for alternans in both nSR and cAF conditions. We also show that increasing ISK counteracts DAD development by enhancing the repolarization force that opposes the Ca2+-dependent depolarization. Taken together, our results suggest that increasing ISK in human atrial cardiomyocytes could promote reentry while protecting against triggered activity. Depending on the leading arrhythmogenic mechanism, ISK inhibition may thus be a beneficial or detrimental anti-AF strategy.NEW & NOTEWORTHY Using our established framework for human atrial myocyte simulations, we investigated the role of the small-conductance Ca2+-activated K+ current (ISK) in the regulation of cell function and the development of Ca2+-driven arrhythmias. We found that ISK inhibition, a promising atrial-selective pharmacological strategy against atrial fibrillation, counteracts the reentry-promoting abbreviation of atrial refractoriness, but renders human atrial myocytes more vulnerable to delayed afterdepolarizations, thus potentially increasing the propensity for ectopic (triggered) activity.
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Affiliation(s)
- Nathaniel T Herrera
- Department of Pharmacology, University of California Davis, Davis, California, United States
| | - Xianwei Zhang
- Department of Pharmacology, University of California Davis, Davis, California, United States
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, California, United States
| | - Mary M Maleckar
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - Jordi Heijman
- Department of Cardiology, Faculty of Health, Medicine, and Life Sciences, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Dobromir Dobrev
- Faculty of Medicine, West German Heart and Vascular Center, Institute of Pharmacology, University Duisburg-Essen, Essen, Germany
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada
- Department of Integrative Physiology, Baylor College of Medicine, Houston, Texas, United States
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, California, United States
| | - Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, California, United States
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4
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Muangkram Y, Himeno Y, Amano A. Clarifying the composition of the ATP consumption factors required for maintaining ion homeostasis in mouse rod photoreceptors. Sci Rep 2023; 13:14161. [PMID: 37644037 PMCID: PMC10465610 DOI: 10.1038/s41598-023-40663-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023] Open
Abstract
To date, no effective treatment has been established for photoreceptor loss due to energy imbalances, but numerous therapeutic approaches have reported some success in slowing photoreceptor degeneration by downregulating energy demand. However, the detailed mechanisms remain unclear. This study aimed to clarify the composition of ATP consumption factors in photoreceptors in darkness and in light. We introduced mathematical formulas for ionic current activities combined with a phototransduction model to form a new mathematical model for estimating the energy expenditure of each ionic current. The proposed model included various ionic currents identified in mouse rods using a gene expression database incorporating an available electrophysiological recording of each specific gene. ATP was mainly consumed by Na+/K+-ATPase and plasma membrane Ca2+-ATPase pumps to remove excess Na+ and Ca2+. The rod consumed 7 [Formula: see text] 107 molecules of ATP s-1, where 65% was used to remove ions from the cyclic nucleotide-gated channel and 20% from the hyperpolarization-activated current in darkness. Increased light intensity raised the energy requirements of the complex phototransduction cascade mechanisms. Nevertheless, the overall energy consumption was less than that in darkness due to the significant reduction in ATPase activities, where the hyperpolarization-activated current proportion increased to 83%. A better understanding of energy demand/supply may provide an effective tool for investigating retinal pathophysiological changes and analyzing novel therapeutic treatments related to the energy consumption of photoreceptors.
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Affiliation(s)
- Yuttamol Muangkram
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga, Japan.
| | - Yukiko Himeno
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga, Japan
| | - Akira Amano
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga, Japan
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5
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Liu T, Li T, Xu D, Wang Y, Zhou Y, Wan J, Huang CLH, Tan X. Small-conductance calcium-activated potassium channels in the heart: expression, regulation and pathological implications. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220171. [PMID: 37122223 PMCID: PMC10150224 DOI: 10.1098/rstb.2022.0171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Ca2+-activated K+ channels are critical to cellular Ca2+ homeostasis and excitability; they couple intracellular Ca2+ and membrane voltage change. Of these, the small, 4-14 pS, conductance SK channels include three, KCNN1-3 encoded, SK1/KCa2.1, SK2/KCa2.2 and SK3/KCa2.3, channel subtypes with characteristic, EC50 ∼ 10 nM, 40 pM, 1 nM, apamin sensitivities. All SK channels, particularly SK2 channels, are expressed in atrial, ventricular and conducting system cardiomyocytes. Pharmacological and genetic modification results have suggested that SK channel block or knockout prolonged action potential durations (APDs) and effective refractory periods (ERPs) particularly in atrial, but also in ventricular, and sinoatrial, atrioventricular node and Purkinje myocytes, correspondingly affect arrhythmic tendency. Additionally, mitochondrial SK channels may decrease mitochondrial Ca2+ overload and reactive oxygen species generation. SK channels show low voltage but marked Ca2+ dependences (EC50 ∼ 300-500 nM) reflecting their α-subunit calmodulin (CaM) binding domains, through which they may be activated by voltage-gated or ryanodine-receptor Ca2+ channel activity. SK function also depends upon complex trafficking and expression processes and associations with other ion channels or subunits from different SK subtypes. Atrial and ventricular clinical arrhythmogenesis may follow both increased or decreased SK expression through decreased or increased APD correspondingly accelerating and stabilizing re-entrant rotors or increasing incidences of triggered activity. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- Ting Liu
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Tao Li
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Cardiology, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Dandi Xu
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Yan Wang
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Yafei Zhou
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Juyi Wan
- Department of Cardiovascular Surgery, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Christopher L-H Huang
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Physiological Laboratory and Department of Biochemistry, University of Cambridge, Cambridge CB2 3EG, UK
| | - Xiaoqiu Tan
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Cardiology, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Physiology, School of Basic Medical Sciences, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
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6
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Zheng D, Wu Q, Zeng P, Li S, Cai Y, Chen S, Luo X, Kuang S, Rao F, Lai Y, Zhou M, Wu F, Yang H, Deng C. Advanced glycation end products induce senescence of atrial myocytes and increase susceptibility of atrial fibrillation in diabetic mice. Aging Cell 2022; 21:e13734. [PMID: 36278684 PMCID: PMC9741501 DOI: 10.1111/acel.13734] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 09/07/2022] [Accepted: 10/02/2022] [Indexed: 12/14/2022] Open
Abstract
Diabetes mellitus (DM) is a common chronic metabolic disease caused by significant accumulation of advanced glycation end products (AGEs). Atrial fibrillation (AF) is a common cardiovascular complication of DM. Here, we aim to clarify the role and mechanism of atrial myocyte senescence in the susceptibility of AF in diabetes. Rapid transesophageal atrial pacing was used to monitor the susceptibility of mice to AF. Whole-cell patch-clamp was employed to record the action potential (AP) and ion channels in single HL-1 cell and mouse atrial myocytes. More importantly, anti-RAGE antibody and RAGE-siRNA AAV9 were used to investigate the relationship among diabetes, aging, and AF. The results showed that elevated levels of p16 and retinoblastoma (Rb) protein in the atrium were associated with increased susceptibility to AF in diabetic mice. Mechanistically, AGEs increased p16/Rb protein expression and the number of SA-β-gal-positive cells, prolonged the action potential duration (APD), reduced protein levels of Cav1.2, Kv1.5, and current density of ICa,L , IKur in HL-1 cells. Anti-RAGE antibody or RAGE-siRNA AAV9 reversed these effects in vitro and in vivo, respectively. Furthermore, downregulating p16 or Rb by siRNA prevented AGEs-mediated reduction of Cav1.2 and Kv1.5 proteins expression. In conclusion, AGEs accelerated atrial electrical remodeling and cellular senescence, contributing to increased AF susceptibility by activating the p16/Rb pathway. Inhibition of RAGE or the p16/Rb pathway may be a potential therapeutic target for AF in diabetes.
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Affiliation(s)
- Dan‐Lin Zheng
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina
| | - Qing‐Rui Wu
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,School of MedicineSouth China University of TechnologyGuangzhouChina
| | - Peng Zeng
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,School of MedicineSouth China University of TechnologyGuangzhouChina
| | - Sui‐Min Li
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina
| | - Yong‐Jiang Cai
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,School of Pharmaceutical SciencesSouthern Medical UniversityGuangzhouChina
| | - Shu‐Zhen Chen
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina
| | - Xue‐Shan Luo
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,School of MedicineSouth China University of TechnologyGuangzhouChina
| | - Su‐Juan Kuang
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina
| | - Fang Rao
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina
| | - Ying‐Yu Lai
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,School of Pharmaceutical SciencesSouthern Medical UniversityGuangzhouChina
| | - Meng‐Yuan Zhou
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina
| | - Fei‐Long Wu
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina
| | - Hui Yang
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina
| | - Chun‐Yu Deng
- Guangdong Provincial Key Laboratory of Clinical PharmacologyResearch Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,Department of Cardiology, Guangdong Cardiovascular InstituteGuangdong Provincial People's Hospital, Guangdong Academy of Medical SciencesGuangzhouChina,School of MedicineSouth China University of TechnologyGuangzhouChina,School of Pharmaceutical SciencesSouthern Medical UniversityGuangzhouChina
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7
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Kubasov IV, Stepanov AV, Panov AA, Chistyakova OV, Sukhov IB, Dobretsov MG. Role of Potassium Currents in the Formation of After-Hyperpolarization Phase of Extracellular Action Potentials Recorded from the Control and Diabetic Rat Heart Ventricular Myocytes. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021060272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Changes in ion channel expression and function associated with cardiac arrhythmogenic remodeling by Sorbs2. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166247. [PMID: 34487812 DOI: 10.1016/j.bbadis.2021.166247] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 08/03/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022]
Abstract
The Sorbin and SH3 domain-containing protein 2 (Sorbs2) is an important component of cardiomyocyte sarcomere. It has been recently reported that loss of Sorbs2 is causally associated with arrhythmogenic cardiomyopathy in human. However, the ionic mechanisms leading to cardiac arrhythmogenesis by Sorbs2 deficiency are unknown. In this study, we hypothesized that Sorbs2 plays an important role in regulating cardiac ion channel expression and function. Using electrophysiological and molecular biological approaches, we found that the Sorbs2 knockout (KO) mice progressively developed cardiac structural and electrical remodeling as early as 1 to 2 months of age and died prematurely at 5 to 7 months of age. Electrocardiographic recordings showed that Sorbs2 KO mice had conduction delays, spontaneous ventricular extrasystoles and polymorphic ventricular tachyarrhythmia. Intracellular recordings revealed abnormal action potentials with depolarized resting potential, reduced upstroke velocity, prolonged repolarization, and effective refractory period in the ventricular preparations of Sorbs2 KO mice. Patch clamp experiments demonstrated that Sorbs2 KO mice displayed distinct abnormalities in the expression and function of cardiac ion channels, including those of the voltage-gated Na+ channels, L-type Ca2+ channels, the voltage-gated K+ channels and the inward-rectifier K+ channels. Moreover, Sorbs2 physically interacted with the RNAs and/or proteins of important cardiac ion channels and directly regulated their expression in vitro. Our results indicate that Sorbs2 plays a pivotal role in the regulation of cardiac channel physiology. Loss of Sorbs2 promotes cardiac ion channelopathies and life-threatening arrhythmias.
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9
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Rahm AK, Wieder T, Gramlich D, Müller ME, Wunsch MN, El Tahry FA, Heimberger T, Sandke S, Weis T, Most P, Katus HA, Thomas D, Lugenbiel P. Differential regulation of K Ca 2.1 (KCNN1) K + channel expression by histone deacetylases in atrial fibrillation with concomitant heart failure. Physiol Rep 2021; 9:e14835. [PMID: 34111326 PMCID: PMC8191401 DOI: 10.14814/phy2.14835] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 01/12/2023] Open
Abstract
Atrial fibrillation (AF) with concomitant heart failure (HF) poses a significant therapeutic challenge. Mechanism‐based approaches may optimize AF therapy. Small‐conductance, calcium‐activated K+ (KCa, KCNN) channels contribute to cardiac action potential repolarization. KCNN1 exhibits predominant atrial expression and is downregulated in chronic AF patients with preserved cardiac function. Epigenetic regulation is suggested by AF suppression following histone deacetylase (HDAC) inhibition. We hypothesized that HDAC‐dependent KCNN1 remodeling contributes to arrhythmogenesis in AF complicated by HF. The aim of this study was to assess KCNN1 and HDAC1–7 and 9 transcript levels in AF/HF patients and in a pig model of atrial tachypacing‐induced AF with reduced left ventricular function. In HL‐1 atrial myocytes, tachypacing and anti‐Hdac siRNAs were employed to investigate effects on Kcnn1 mRNA levels. KCNN1 expression displayed side‐specific remodeling in AF/HF patients with upregulation in left and suppression in right atrium. In pigs, KCNN1 remodeling showed intermediate phenotypes. HDAC levels were differentially altered in humans and pigs, reflecting highly variable epigenetic regulation. Tachypacing recapitulated downregulation of Hdacs1, 3, 4, 6, and 7 with a tendency towards reduced Kcnn1 levels in vitro, indicating that atrial high rates induce remodeling. Finally, Kcnn1 expression was decreased by knockdown of Hdacs2, 3, 6, and 7 and enhanced by genetic Hdac9 inactivation, while anti‐Hdac1, 4, and 5 siRNAs did not affect Kcnn1 transcript levels. In conclusion, KCNN1 and HDAC expression is differentially remodeled in AF complicated by HF. Direct regulation of KCNN1 by HDACs in atrial myocytes provides a basis for mechanism‐based antiarrhythmic therapy.
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Affiliation(s)
- Ann-Kathrin Rahm
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Teresa Wieder
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, Germany
| | - Dominik Gramlich
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Mara Elena Müller
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Maximilian N Wunsch
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Fadwa A El Tahry
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Tanja Heimberger
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Steffi Sandke
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Tanja Weis
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Patrick Most
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Patrick Lugenbiel
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, Germany.,HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, Germany
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10
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Rahm AK, Gramlich D, Wieder T, Müller ME, Schoeffel A, El Tahry FA, Most P, Heimberger T, Sandke S, Weis T, Ullrich ND, Korff T, Lugenbiel P, Katus HA, Thomas D. Trigger-Specific Remodeling of K Ca2 Potassium Channels in Models of Atrial Fibrillation. Pharmgenomics Pers Med 2021; 14:579-590. [PMID: 34045886 PMCID: PMC8144362 DOI: 10.2147/pgpm.s290291] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 04/06/2021] [Indexed: 11/23/2022] Open
Abstract
AIM Effective antiarrhythmic treatment of atrial fibrillation (AF) constitutes a major challenge, in particular, when concomitant heart failure (HF) is present. HF-associated atrial arrhythmogenesis is distinctly characterized by prolonged atrial refractoriness. Small-conductance, calcium-activated K+ (KCa, SK, KCNN) channels contribute to cardiac action potential repolarization and are implicated in AF susceptibility and therapy. The mechanistic impact of AF/HF-related triggers on atrial KCa channels is not known. We hypothesized that tachycardia, stretch, β-adrenergic stimulation, and hypoxia differentially determine KCa2.1-2.3 channel remodeling in atrial cells. METHODS KCNN1-3 transcript levels were assessed in AF/HF patients and in a pig model of atrial tachypacing-induced AF with reduced left ventricular function. HL-1 atrial myocytes were subjected to proarrhythmic triggers to investigate the effects on Kcnn mRNA and KCa channel protein. RESULTS Atrial KCNN1-3 expression was reduced in AF/HF patients. KCNN2 and KCNN3 suppression was recapitulated in the corresponding pig model. In contrast to human AF, KCNN1 remained unchanged in pigs. Channel- and stressor-specific remodeling was revealed in vitro. Lower expression levels of KCNN1/KCa2.1 were linked to stretch and β-adrenergic stimulation. Furthermore, KCNN3/KCa2.3 expression was suppressed upon tachypacing and hypoxia. Finally, KCNN2/KCa2.2 abundance was specifically enhanced by hypoxia. CONCLUSION Reduction of KCa2.1-2.3 channel expression might contribute to the action potential prolongation in AF complicated by HF. Subtype-specific KCa2 channel remodeling induced by tachypacing, stretch, β-adrenergic stimulation, or hypoxia is expected to differentially determine atrial remodeling, depending on patient-specific activation of each triggering factor. Stressor-dependent KCa2 regulation in atrial myocytes provides a starting point for mechanism-based antiarrhythmic therapy.
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Affiliation(s)
- Ann-Kathrin Rahm
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, 69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, 69120, Germany
| | - Dominik Gramlich
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, 69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, 69120, Germany
| | - Teresa Wieder
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, 69120, Germany
| | - Mara Elena Müller
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, 69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, 69120, Germany
| | - Axel Schoeffel
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, 69120, Germany
| | - Fadwa A El Tahry
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
| | - Patrick Most
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, 69120, Germany
| | - Tanja Heimberger
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, 69120, Germany
| | - Steffi Sandke
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, 69120, Germany
| | - Tanja Weis
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, 69120, Germany
| | - Nina D Ullrich
- Institute of Physiology and Pathophysiology, Department of Cardiovascular Physiology, Heidelberg University, Heidelberg, 69120, Germany
| | - Thomas Korff
- Institute of Physiology and Pathophysiology, Department of Cardiovascular Physiology, Heidelberg University, Heidelberg, 69120, Germany
- European Center for Angioscience (ECAS), Medical Faculty Mannheim, Heidelberg University, Mannheim, 68167, Germany
| | - Patrick Lugenbiel
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, 69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, 69120, Germany
| | - Hugo A Katus
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, 69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, 69120, Germany
| | - Dierk Thomas
- Department of Cardiology, Medical University Hospital Heidelberg, Heidelberg, 69120, Germany
- HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Heidelberg, 69120, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Heidelberg/Mannheim, University of Heidelberg, Heidelberg, 69120, Germany
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11
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Vrachatis DA, Papathanasiou KA, Kossyvakis C, Giotaki SG, Raisakis K, Iliodromitis KE, Reimers B, Stefanini GG, Cleman M, Sianos G, Lansky A, Deftereos SG, Giannopoulos G. Atrial fibrillation risk in patients suffering from type I diabetes mellitus. A review of clinical and experimental evidence. Diabetes Res Clin Pract 2021; 174:108724. [PMID: 33647332 DOI: 10.1016/j.diabres.2021.108724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 01/31/2021] [Accepted: 02/09/2021] [Indexed: 12/12/2022]
Abstract
Atrial fibrillation (AF) and diabetes mellitus (DM) are commonly encountered in clinical practice. Although, the long term macrovascular and microvascular sequela of DM are well validated, the association between the less prevalent type 1 DM (T1DM) and atrial arrhythmogenesis is poorly understood. In the present review we highlight the current experimental and clinical data addressing this complex interaction. Animal studies support that T1DM, characterized by insulin deficiency and glycemic variability, impairs phosphatidylinositol 3‑kinase (PI3K)/protein kinase B signaling pathway. This pathway holds a central role in atrial electrical and structural remodeling responsible for arrhythmia initiation and maintenance. The molecular ''footprint'' of T1DM in atrial myocytes seems to involve a state of increased oxidative stress, impaired glucose transportation, ionic channel dysregulation and eventually fibrosis. On the contrary only a few clinical studies have examined the role of T1DM as an independent risk factor for AF development, and are discussed here. Further research is needed to solidify the real magnitude of this association and to investigate the clinical implications of PI3K molecular signaling pathway in atrial fibrillation management.
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Affiliation(s)
- Dimitrios A Vrachatis
- Humanitas Clinical and Research Center IRCCS, Milan, Italy; National and Kapodistrian University of Athens, Athens, Greece
| | | | | | | | | | | | | | | | - Michael Cleman
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - George Sianos
- Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Alexandra Lansky
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
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12
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Qi MM, Qian LL, Wang RX. Modulation of SK Channels: Insight Into Therapeutics of Atrial Fibrillation. Heart Lung Circ 2021; 30:1130-1139. [PMID: 33642173 DOI: 10.1016/j.hlc.2021.01.009] [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: 05/27/2020] [Revised: 01/12/2021] [Accepted: 01/31/2021] [Indexed: 11/19/2022]
Abstract
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia in the world. Although much technological progress in the treatment of AF has been made, there is an urgent need for better treatment of AF due to its high rates of morbidity and mortality. The anti-arrhythmic drugs currently approved for marketing have significant limitations and side effects such as life-threatening ventricular arrhythmias and hypotension. The small conductance Ca2+-activated K+ channels (SK channels) are dependent on intracellular Ca2+ concentrations, which tightly integrate with membrane potential. Given the predominant expression in the atria of many species, including humans, they are now emerging as a therapeutic target for treating AF. This review aimed to illustrate the characteristics and function of SK channels. Moreover, it discussed the regulation of SK channels and their potential as a therapeutic target of AF.
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Affiliation(s)
- Miao-Miao Qi
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu, China
| | - Ling-Ling Qian
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu, China
| | - Ru-Xing Wang
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu, China.
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13
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Zhang XD, Thai PN, Lieu DK, Chiamvimonvat N. Cardiac small-conductance calcium-activated potassium channels in health and disease. Pflugers Arch 2021; 473:477-489. [PMID: 33624131 PMCID: PMC7940285 DOI: 10.1007/s00424-021-02535-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/22/2022]
Abstract
Small-conductance Ca2+-activated K+ (SK, KCa2) channels are encoded by KCNN genes, including KCNN1, 2, and 3. The channels play critical roles in the regulation of cardiac excitability and are gated solely by beat-to-beat changes in intracellular Ca2+. The family of SK channels consists of three members with differential sensitivity to apamin. All three isoforms are expressed in human hearts. Studies over the past two decades have provided evidence to substantiate the pivotal roles of SK channels, not only in healthy heart but also with diseases including atrial fibrillation (AF), ventricular arrhythmia, and heart failure (HF). SK channels are prominently expressed in atrial myocytes and pacemaking cells, compared to ventricular cells. However, the channels are significantly upregulated in ventricular myocytes in HF and pulmonary veins in AF models. Interests in cardiac SK channels are further fueled by recent studies suggesting the possible roles of SK channels in human AF. Therefore, SK channel may represent a novel therapeutic target for atrial arrhythmias. Furthermore, SK channel function is significantly altered by human calmodulin (CaM) mutations, linked to life-threatening arrhythmia syndromes. The current review will summarize recent progress in our understanding of cardiac SK channels and the roles of SK channels in the heart in health and disease.
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Affiliation(s)
- Xiao-Dong Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, One Shields Avenue, GBSF 6315, Davis, CA, 95616, USA.
- Department of Veterans Affairs, Northern California Health Care System, 10535 Hospital Way, Mather, CA, 95655, USA.
| | - Phung N Thai
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, One Shields Avenue, GBSF 6315, Davis, CA, 95616, USA
- Department of Veterans Affairs, Northern California Health Care System, 10535 Hospital Way, Mather, CA, 95655, USA
| | - Deborah K Lieu
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, One Shields Avenue, GBSF 6315, Davis, CA, 95616, USA
| | - Nipavan Chiamvimonvat
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of California, Davis, One Shields Avenue, GBSF 6315, Davis, CA, 95616, USA.
- Department of Veterans Affairs, Northern California Health Care System, 10535 Hospital Way, Mather, CA, 95655, USA.
- Department of Pharmacology, School of Medicine, University of California, Davis, Davis, CA, 95616, USA.
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14
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Mesubi OO, Rokita AG, Abrol N, Wu Y, Chen B, Wang Q, Granger JM, Tucker-Bartley A, Luczak ED, Murphy KR, Umapathi P, Banerjee PS, Boronina TN, Cole RN, Maier LS, Wehrens XH, Pomerantz JL, Song LS, Ahima RS, Hart GW, Zachara NE, Anderson ME. Oxidized CaMKII and O-GlcNAcylation cause increased atrial fibrillation in diabetic mice by distinct mechanisms. J Clin Invest 2021; 131:95747. [PMID: 33151911 PMCID: PMC7810480 DOI: 10.1172/jci95747] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 11/03/2020] [Indexed: 12/21/2022] Open
Abstract
Diabetes mellitus (DM) and atrial fibrillation (AF) are major unsolved public health problems, and diabetes is an independent risk factor for AF. However, the mechanism(s) underlying this clinical association is unknown. ROS and protein O-GlcNAcylation (OGN) are increased in diabetic hearts, and calmodulin kinase II (CaMKII) is a proarrhythmic signal that may be activated by ROS (oxidized CaMKII, ox-CaMKII) and OGN (OGN-CaMKII). We induced type 1 (T1D) and type 2 DM (T2D) in a portfolio of genetic mouse models capable of dissecting the role of ROS and OGN at CaMKII and global OGN in diabetic AF. Here, we showed that T1D and T2D significantly increased AF, and this increase required CaMKII and OGN. T1D and T2D both required ox-CaMKII to increase AF; however, we did not detect OGN-CaMKII or a role for OGN-CaMKII in diabetic AF. Collectively, our data affirm CaMKII as a critical proarrhythmic signal in diabetic AF and suggest ROS primarily promotes AF by ox-CaMKII, while OGN promotes AF by a CaMKII-independent mechanism(s). These results provide insights into the mechanisms for increased AF in DM and suggest potential benefits for future CaMKII and OGN targeted therapies.
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Affiliation(s)
- Olurotimi O. Mesubi
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Adam G. Rokita
- Division of Cardiovascular Medicine and Cardiovascular Research Center, Carver College of Medicine, Iowa City, Iowa, USA
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Neha Abrol
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yuejin Wu
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Biyi Chen
- Division of Cardiovascular Medicine and Cardiovascular Research Center, Carver College of Medicine, Iowa City, Iowa, USA
| | - Qinchuan Wang
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jonathan M. Granger
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Anthony Tucker-Bartley
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Elizabeth D. Luczak
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kevin R. Murphy
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Priya Umapathi
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Partha S. Banerjee
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Tatiana N. Boronina
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Robert N. Cole
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Lars S. Maier
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Xander H. Wehrens
- Department of Molecular Physiology and Biophysics, Department of Medicine (Cardiology), Department of Pediatrics, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Joel L. Pomerantz
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Institute for Cell Engineering
| | - Long-Sheng Song
- Division of Cardiovascular Medicine and Cardiovascular Research Center, Carver College of Medicine, Iowa City, Iowa, USA
| | - Rexford S. Ahima
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine
| | - Gerald W. Hart
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Natasha E. Zachara
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Mark E. Anderson
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, and
- Department of Physiology and Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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15
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The regulation of the small-conductance calcium-activated potassium current and the mechanisms of sex dimorphism in J wave syndrome. Pflugers Arch 2021; 473:491-506. [PMID: 33411079 DOI: 10.1007/s00424-020-02500-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/20/2020] [Accepted: 11/25/2020] [Indexed: 12/16/2022]
Abstract
Apamin-sensitive small-conductance calcium-activated potassium (SK) current (IKAS) plays an important role in cardiac repolarization under a variety of physiological and pathological conditions. The regulation of cardiac IKAS relies on SK channel expression, intracellular Ca2+, and interaction between SK channel and intracellular Ca2+. IKAS activation participates in multiple types of arrhythmias, including atrial fibrillation, ventricular tachyarrhythmias, and automaticity and conduction abnormality. Recently, sex dimorphisms in autonomic control have been noticed in IKAS activation, resulting in sex-differentiated action potential morphology and arrhythmogenesis. This review provides an update on the Ca2+-dependent regulation of cardiac IKAS and the role of IKAS on arrhythmias, with a special focus on sex differences in IKAS activation. We propose that sex dimorphism in autonomic control of IKAS may play a role in J wave syndrome.
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16
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Rahm AK, Wieder T, Gramlich D, Müller ME, Wunsch MN, El Tahry FA, Heimberger T, Weis T, Most P, Katus HA, Thomas D, Lugenbiel P. HDAC2-dependent remodeling of K Ca2.2 (KCNN2) and K Ca2.3 (KCNN3) K + channels in atrial fibrillation with concomitant heart failure. Life Sci 2020; 266:118892. [PMID: 33310041 DOI: 10.1016/j.lfs.2020.118892] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 11/30/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022]
Abstract
AIMS Atrial fibrillation (AF) with concomitant heart failure (HF) is associated with prolonged atrial refractoriness. Small-conductance, calcium-activated K+ (KCa, KCNN) channels promote action potential (AP) repolarization. KCNN2 and KCNN3 variants are associated with AF risk. In addition, histone deacetylase (HDAC)-related epigenetic mechanisms have been implicated in AP regulation. We hypothesized that HDAC2-dependent remodeling of KCNN2 and KCNN3 expression contributes to atrial arrhythmogenesis in AF complicated by HF. The objectives were to assess HDAC2 and KCNN2/3 transcript levels in AF/HF patients and in a pig model, and to investigate cellular epigenetic effects of HDAC2 inactivation on KCNN expression. MATERIALS AND METHODS HDAC2 and KCNN2/3 transcript levels were quantified in patients with AF and HF, and in a porcine model of atrial tachypacing-induced AF and reduced left ventricular function. Tachypacing and anti-Hdac2 siRNA treatment were employed in HL-1 atrial myocytes to study effects on KCNN2/3 mRNA and KCa protein abundance. KEY FINDINGS Atrial KCNN2 and KCNN3 expression was reduced in AF/HF patients and in a corresponding pig model. HDAC2 displayed significant downregulation in humans and a tendency towards reduced expression in right atrial tissue of pigs. Tachypacing recapitulated downregulation of Kcnn2/KCa2.2, Kcnn3/KCa2.3 and Hdac2/HDAC2, indicating that high atrial rates trigger epigenetic remodeling mechanisms. Finally, knock-down of Hdac2 in vitro reduced Kcnn3/KCa2.3 expression. SIGNIFICANCE KCNN2/3 and HDAC2 expression is suppressed in AF complicated by HF. Hdac2 directly regulates Kcnn3 mRNA levels in atrial cells. The mechanistic and therapeutic significance of epigenetic electrophysiological effects in AF requires further validation.
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Affiliation(s)
- Ann-Kathrin Rahm
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Teresa Wieder
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Dominik Gramlich
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Mara Elena Müller
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Maximilian N Wunsch
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Fadwa A El Tahry
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Tanja Heimberger
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Tanja Weis
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Patrick Most
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Hugo A Katus
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
| | - Dierk Thomas
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany.
| | - Patrick Lugenbiel
- Department of Cardiology, Medical University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; HCR (Heidelberg Center for Heart Rhythm Disorders), University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
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17
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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18
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Ding Y, Yang J, Chen P, Lu T, Jiao K, Tester DJ, Giudicessi JR, Jiang K, Ackerman MJ, Li Y, Wang DW, Lee H, Wang DW, Xu X. Knockout of SORBS2 Protein Disrupts the Structural Integrity of Intercalated Disc and Manifests Features of Arrhythmogenic Cardiomyopathy. J Am Heart Assoc 2020; 9:e017055. [PMID: 32808564 PMCID: PMC7660791 DOI: 10.1161/jaha.119.017055] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 07/13/2020] [Indexed: 12/21/2022]
Abstract
Background Sorbs2b (sorbin and SH3 domain-containing 2b) was recently identified as a cardiomyopathy gene from a zebrafish mutagenesis screen. However, cardiac functions of its mammalian ortholog remain elusive. Methods and Results We conducted a detailed expression and subcellular localization analysis of Sorbs2 ortholog in mice and a phenotypic characterization in Sorbs2 knockout mice. Sorbs2 is highly expressed in the mouse heart and encodes an adhesion junction/desmosome protein that is mainly localized to the intercalated disc. A mutation with near complete depletion of the Sorbs2 protein in mice results in phenotypes characteristic of human arrhythmogenic cardiomyopathy (ACM), including right ventricular dilation, right ventricular dysfunction, spontaneous ventricular tachycardia, and premature death. Sorbs2 is required to maintain the structural integrity of intercalated disc. Its absence resulted in profound cardiac electrical remodeling with impaired impulse conduction and action potential derangements. Targeted sequencing of human patients with ACM identified 2 rare splicing variants classified as likely pathogenic were in 2 unrelated individuals with ACM from a cohort of 59 patients with ACM. Conclusions The Sorbs2 knockout mouse manifests several key features reminiscent of human ACM. Although the candidacy of SORBS2 as a new ACM-susceptibility gene is supported by preliminary human genetics study, future validation in larger cohorts with ACM is needed.
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Affiliation(s)
- Yonghe Ding
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMN
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
| | - Jingchun Yang
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMN
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
| | - Peng Chen
- Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic DisordersDivision of CardiologyDepartments of Internal Medicine and Genetic Diagnosis CenterTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Tong Lu
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
| | - Kunli Jiao
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMN
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
- Division of CardiologyXinhua HospitalShanghai Jiaotong UniversityShanghaiChina
| | | | | | - Kai Jiang
- Division of Nephrology and HypertensionMayo ClinicRochesterMN
| | - Michael J. Ackerman
- Department of Cardiovascular Medicine (Division of Heart Rhythm Services)Mayo ClinicRochesterMN
- Pediatric and Adolescent Medicine (Division of Pediatric Cardiology)Mayo ClinicRochesterMN
- Molecular Pharmacology and Experimental Therapeutics (Windland Smith Rice Sudden Death Genomics Laboratory)Mayo ClinicRochesterMN
| | - Yigang Li
- Division of CardiologyXinhua HospitalShanghai Jiaotong UniversityShanghaiChina
| | - Dao Wu Wang
- State Key Laboratory of Reproductive MedicineClinical Center of Reproductive Medicine and Department of CardiologyFirst Affiliated Hospital of Nanjing Medical UniversityNanjingChina
| | - HoN‐chi Lee
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
| | - Dao Wen Wang
- Hubei Key Laboratory of Genetics and Molecular Mechanism of Cardiologic DisordersDivision of CardiologyDepartments of Internal Medicine and Genetic Diagnosis CenterTongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhanChina
| | - Xiaolei Xu
- Department of Biochemistry and Molecular BiologyMayo ClinicRochesterMN
- Department of Cardiovascular MedicineMayo ClinicRochesterMN
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19
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Scholman KT, Meijborg VMF, Gálvez-Montón C, Lodder EM, Boukens BJ. From Genome-Wide Association Studies to Cardiac Electrophysiology: Through the Maze of Biological Complexity. Front Physiol 2020; 11:557. [PMID: 32536879 PMCID: PMC7267057 DOI: 10.3389/fphys.2020.00557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/04/2020] [Indexed: 12/19/2022] Open
Abstract
Genome Wide Association Studies (GWAS) have provided an enormous amount of data on genomic loci associated with cardiac electrophysiology and arrhythmias. Clinical relevance, however, remains unclear since GWAS do not provide a mechanistic explanation for this association. Determining the electrophysiological relevance of variants for arrhythmias would aid development of risk stratification models for patients with arrhythmias. In this review, we give an overview of genetic variants related to ECG intervals and arrhythmogenic pathologies and discuss how these variants may influence cardiac electrophysiology and the occurrence of arrhythmias.
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Affiliation(s)
- Koen T Scholman
- Department of Medical Biology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Veronique M F Meijborg
- Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Netherlands Heart Institute, Utrecht, Netherlands
| | - Carolina Gálvez-Montón
- ICREC Research Program, Germans Trias i Pujol Health Science Research Institute, Badalona, Spain.,CIBERCV, Instituto de Salud Carlos III, Madrid, Spain
| | - Elisabeth M Lodder
- Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Bastiaan J Boukens
- Department of Medical Biology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
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20
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Jansen HJ, Bohne LJ, Gillis AM, Rose RA. Atrial remodeling and atrial fibrillation in acquired forms of cardiovascular disease. Heart Rhythm O2 2020; 1:147-159. [PMID: 34113869 PMCID: PMC8183954 DOI: 10.1016/j.hroo.2020.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Atrial fibrillation (AF) is prevalent in common conditions and acquired forms of heart disease, including diabetes mellitus (DM), hypertension, cardiac hypertrophy, and heart failure. AF is also prevalent in aging. Although acquired heart disease is common in aging individuals, age is also an independent risk factor for AF. Importantly, not all individuals age at the same rate. Rather, individuals of the same chronological age can vary in health status from fit to frail. Frailty can be quantified using a frailty index, which can be used to assess heterogeneity in individuals of the same chronological age. AF is thought to occur in association with electrical remodeling due to changes in ion channel expression or function as well as structural remodeling due to fibrosis, myocyte hypertrophy, or adiposity. These forms of remodeling can lead to triggered activity and electrical re-entry, which are fundamental mechanisms of AF initiation and maintenance. Nevertheless, the underlying determinants of electrical and structural remodeling are distinct in different conditions and disease states. In this focused review, we consider the factors leading to atrial electrical and structural remodeling in human patients and animal models of acquired cardiovascular disease or associated risk factors. Our goal is to identify similarities and differences in the cellular and molecular bases for atrial electrical and structural remodeling in conditions including DM, hypertension, hypertrophy, heart failure, aging, and frailty.
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Affiliation(s)
- Hailey J Jansen
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Loryn J Bohne
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Anne M Gillis
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robert A Rose
- Department of Cardiac Sciences, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Physiology and Pharmacology, Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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21
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Asfaw TN, Tyan L, Glukhov AV, Bondarenko VE. A compartmentalized mathematical model of mouse atrial myocytes. Am J Physiol Heart Circ Physiol 2020; 318:H485-H507. [PMID: 31951471 DOI: 10.1152/ajpheart.00460.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Various experimental mouse models are extensively used to research human diseases, including atrial fibrillation, the most common cardiac rhythm disorder. Despite this, there are no comprehensive mathematical models that describe the complex behavior of the action potential and [Ca2+]i transients in mouse atrial myocytes. Here, we develop a novel compartmentalized mathematical model of mouse atrial myocytes that combines the action potential, [Ca2+]i dynamics, and β-adrenergic signaling cascade for a subpopulation of right atrial myocytes with developed transverse-axial tubule system. The model consists of three compartments related to β-adrenergic signaling (caveolae, extracaveolae, and cytosol) and employs local control of Ca2+ release. It also simulates ionic mechanisms of action potential generation and describes atrial-specific Ca2+ handling as well as frequency dependences of the action potential and [Ca2+]i transients. The model showed that the T-type Ca2+ current significantly affects the later stage of the action potential, with little effect on [Ca2+]i transients. The block of the small-conductance Ca2+-activated K+ current leads to a prolongation of the action potential at high intracellular Ca2+. Simulation results obtained from the atrial model cells were compared with those from ventricular myocytes. The developed model represents a useful tool to study complex electrical properties in the mouse atria and could be applied to enhance the understanding of atrial physiology and arrhythmogenesis.NEW & NOTEWORTHY A new compartmentalized mathematical model of mouse right atrial myocytes was developed. The model simulated action potential and Ca2+ dynamics at baseline and after stimulation of the β-adrenergic signaling system. Simulations showed that the T-type Ca2+ current markedly prolonged the later stage of atrial action potential repolarization, with a minor effect on [Ca2+]i transients. The small-conductance Ca2+-activated K+ current block resulted in prolongation of the action potential only at the relatively high intracellular Ca2+.
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Affiliation(s)
- Tesfaye Negash Asfaw
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia
| | - Leonid Tyan
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Alexey V Glukhov
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Vladimir E Bondarenko
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia.,Neuroscience Institute, Georgia State University, Atlanta, Georgia
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22
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Endothelium-Dependent Hyperpolarization (EDH) in Diabetes: Mechanistic Insights and Therapeutic Implications. Int J Mol Sci 2019; 20:ijms20153737. [PMID: 31370156 PMCID: PMC6695796 DOI: 10.3390/ijms20153737] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/25/2019] [Accepted: 07/30/2019] [Indexed: 02/07/2023] Open
Abstract
Diabetes mellitus is one of the major risk factors for cardiovascular disease and is an important health issue worldwide. Long-term diabetes causes endothelial dysfunction, which in turn leads to diabetic vascular complications. Endothelium-derived nitric oxide is a major vasodilator in large-size vessels, and the hyperpolarization of vascular smooth muscle cells mediated by the endothelium plays a central role in agonist-mediated and flow-mediated vasodilation in resistance-size vessels. Although the mechanisms underlying diabetic vascular complications are multifactorial and complex, impairment of endothelium-dependent hyperpolarization (EDH) of vascular smooth muscle cells would contribute at least partly to the initiation and progression of microvascular complications of diabetes. In this review, we present the current knowledge about the pathophysiology and underlying mechanisms of impaired EDH in diabetes in animals and humans. We also discuss potential therapeutic approaches aimed at the prevention and restoration of EDH in diabetes.
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23
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Metformin Regulates the Expression of SK2 and SK3 in the Atria of Rats With Type 2 Diabetes Mellitus Through the NOX4/p38MAPK Signaling Pathway. J Cardiovasc Pharmacol 2019; 72:205-213. [PMID: 30188871 DOI: 10.1097/fjc.0000000000000615] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
We previously found that metformin regulates the ion current conducted by the small conductance calcium-activated potassium channels (SK channels) in the atria of rats with type 2 diabetes mellitus (T2DM) as well as the mRNA and protein expression of the SK2 and SK3 subtypes of SK channels. In this study, we hypothesized that the nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4)/p38 mitogen-activated protein kinase (p38MAPK) signaling pathway was involved in the metformin-mediated regulation of SK2 and SK3 expression in the atria of rats with T2DM. We randomly divided Wistar rats into the control group, the untreated T2DM group, the metformin-treated group, the group receiving subcutaneous injections of the nicotinamide adenine dinucleotide phosphate oxidase (NOX) inhibitor diphenyleneiodonium (DPI), and the group receiving tail vein injections of the p38MAPK agonist anisomycin. Real-time polymerase chain reaction, Western blot, and immunohistochemistry were applied to examine the expression levels of SK2, SK3, NOX4, and phospho-p38MAPK (p-p38MAPK) mRNAs and proteins in the atrial tissue of relevant groups. We observed that the expression levels of NOX4 mRNA and protein and p-p38MAPK protein were significantly elevated in the atria of rats with T2DM compared with the control group. In addition, SK2 protein expression was reduced, whereas SK3 protein expression was increased. The 8-week treatment with metformin markedly reduced the expression levels of NOX4 mRNA and protein and p-p38MAPK protein, upregulated the SK2 expression, and downregulated the SK3 expression. Tail vein injection with anisomycin significantly increased the p-p38MAPK expression while further inhibiting the expression of SK2 and enhancing the expression of SK3. Subcutaneous injection with DPI considerably inhibited the expression of NOX4, further enhanced the expression of SK2 and suppressed the expression of SK3. In addition, subcutaneous injection with DPI significantly suppressed the phosphorylation of p38MAPK. In conclusion, the NOX4/p38MAPK signaling pathway mediates the downregulation of SK2 and the upregulation of SK3 in the atria of rats with T2DM. Long-term metformin treatment upregulates SK2 protein expression and downregulates SK3 protein expression by inhibiting the NOX4/p38MAPK signaling pathway.
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24
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Jin X, Jiang Y, Xue G, Yuan Y, Zhu H, Zhan L, Zhuang Y, Huang Q, Shi L, Zhao Y, Li P, Sun Y, Su W, Zhang Y, Yang B, Lu Y, Wang Z, Pan Z. Increase of late sodium current contributes to enhanced susceptibility to atrial fibrillation in diabetic mice. Eur J Pharmacol 2019; 857:172444. [PMID: 31185218 DOI: 10.1016/j.ejphar.2019.172444] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/02/2019] [Accepted: 06/07/2019] [Indexed: 01/10/2023]
Abstract
Studies demonstrated that the incidence of atrial fibrillation is significantly increased in patients with diabetes mellitus. Increase of late sodium current (INaL) has been associated with atrial arrhythmias. However, the role of INaL in the setting of atrial fibrillation in diabetes mellitus remained unknown. In this study, we investigated the alteration of INaL in the atria of diabetic mice and the therapeutic effect of its inhibitor (GS967) on the susceptibility of atrial fibrillation. The whole-cell patch-clamp technique was used to detect single cell electrical activities. The results showed that the density of INaL in diabetic cardiomyocytes was larger than that of the control cells at the holding potential of -100 mV. The action potential duration at both 50% and 90% repolarization, APD50 and APD90, respectively, was markedly increased in diabetic mice than in controls. GS967 application inhibited INaL and shortened APD of diabetic mice. High-frequency electrical stimuli were used to induce atrial arrhythmias. We found that the occurrence rate of atrial fibrillation was significantly increased in diabetic mice, which was alleviated by the administration of GS967. In GS967-treated diabetic mice, the INaL current density was reduced and APD was shortened. In conclusion, the susceptibility to atrial fibrillation was increased in diabetic mice, which is associated with the increased late sodium current and the consequent prolongation of action potential. Inhibition of INaL by GS967 is beneficial against the occurrence of atrial fibrillation in diabetic mice.
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Affiliation(s)
- Xuexin Jin
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Yuan Jiang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Genlong Xue
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Yin Yuan
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Haixia Zhu
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Linfeng Zhan
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Yuting Zhuang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Qihe Huang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Ling Shi
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Yue Zhao
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Penghui Li
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Yilin Sun
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Wanzhen Su
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Yang Zhang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China
| | - Baofeng Yang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China.
| | - Yanjie Lu
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China.
| | - Zhiguo Wang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China.
| | - Zhenwei Pan
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Medicine Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, Heilongjiang, 150081, PR China.
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25
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Bohne LJ, Johnson D, Rose RA, Wilton SB, Gillis AM. The Association Between Diabetes Mellitus and Atrial Fibrillation: Clinical and Mechanistic Insights. Front Physiol 2019; 10:135. [PMID: 30863315 PMCID: PMC6399657 DOI: 10.3389/fphys.2019.00135] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 02/04/2019] [Indexed: 01/16/2023] Open
Abstract
A number of clinical studies have reported that diabetes mellitus (DM) is an independent risk factor for Atrial fibrillation (AF). After adjustment for other known risk factors including age, sex, and cardiovascular risk factors, DM remains a significant if modest risk factor for development of AF. The mechanisms underlying the increased susceptibility to AF in DM are incompletely understood, but are thought to involve electrical, structural, and autonomic remodeling in the atria. Electrical remodeling in DM may involve alterations in gap junction function that affect atrial conduction velocity due to changes in expression or localization of connexins. Electrical remodeling can also occur due to changes in atrial action potential morphology in association with changes in ionic currents, such as sodium or potassium currents, that can affect conduction velocity or susceptibility to triggered activity. Structural remodeling in DM results in atrial fibrosis, which can alter conduction patterns and susceptibility to re-entry in the atria. In addition, increases in atrial adipose tissue, especially in Type II DM, can lead to disruptions in atrial conduction velocity or conduction patterns that may affect arrhythmogenesis. Whether the insulin resistance in type II DM activates unique intracellular signaling pathways independent of obesity requires further investigation. In addition, the relationship between incident AF and glycemic control requires further study.
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Affiliation(s)
- Loryn J Bohne
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Dustin Johnson
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Robert A Rose
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Stephen B Wilton
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
| | - Anne M Gillis
- Department of Cardiac Sciences and Department of Physiology and Pharmacology, University of Calgary and Libin Cardiovascular Institute of Alberta, Calgary, AB, Canada
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26
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Ling TY, Yi F, Lu T, Wang XL, Sun X, Willis MS, Wu LQ, Shen WK, Adelman JP, Lee HC. F-box protein-32 down-regulates small-conductance calcium-activated potassium channel 2 in diabetic mouse atria. J Biol Chem 2019; 294:4160-4168. [PMID: 30635400 DOI: 10.1074/jbc.ra118.003837] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 12/28/2018] [Indexed: 11/06/2022] Open
Abstract
Diabetes mellitus (DM) is an independent risk factor for atrial fibrillation, but the underlying ionic mechanism for this association remains unclear. We recently reported that expression of the small-conductance calcium-activated potassium channel 2 (SK2, encoded by KCCN2) in atria from diabetic mice is significantly down-regulated, resulting in reduced SK currents in atrial myocytes from these mice. We also reported that the level of SK2 mRNA expression is not reduced in DM atria but that the ubiquitin-proteasome system (UPS), a major mechanism of intracellular protein degradation, is activated in vascular smooth muscle cells in DM. This suggests a possible role of the UPS in reduced SK currents. To test this possibility, we examined the role of the UPS in atrial SK2 down-regulation in DM. We found that a muscle-specific E3 ligase, F-box protein 32 (FBXO-32, also called atrogin-1), was significantly up-regulated in diabetic mouse atria. Enhanced FBXO-32 expression in atrial cells significantly reduced SK2 protein expression, and siRNA-mediated FBXO-32 knockdown increased SK2 protein expression. Furthermore, co-transfection of SK2 with FBXO-32 complementary DNA in HEK293 cells significantly reduced SK2 expression, whereas co-transfection with atrogin-1ΔF complementary DNA (a nonfunctional FBXO-32 variant in which the F-box domain is deleted) did not have any effects on SK2. These results indicate that FBXO-32 contributes to SK2 down-regulation and that the F-box domain is essential for FBXO-32 function. In conclusion, DM-induced SK2 channel down-regulation appears to be due to an FBXO-32-dependent increase in UPS-mediated SK2 protein degradation.
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Affiliation(s)
- Tian-You Ling
- From the Department of Cardiology, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China.,the Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Fu Yi
- the Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota 55905, .,the Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
| | - Tong Lu
- the Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Xiao-Li Wang
- the Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Xiaojing Sun
- the Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | - Monte S Willis
- the Department of Pathology and Laboratory Medicine, Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Li-Qun Wu
- From the Department of Cardiology, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai 200025, China
| | - Win-Kuang Shen
- the Department of Cardiovascular Diseases, Mayo Clinic, Phoenix, Arizona 85259, and
| | - John P Adelman
- the Vollum Institute, Oregon Health and Science University, Portland, Oregon 97239
| | - Hon-Chi Lee
- the Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota 55905,
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27
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Gu M, Zhu Y, Yin X, Zhang DM. Small-conductance Ca 2+-activated K + channels: insights into their roles in cardiovascular disease. Exp Mol Med 2018; 50:1-7. [PMID: 29651007 PMCID: PMC5938042 DOI: 10.1038/s12276-018-0043-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 12/11/2017] [Accepted: 12/12/2017] [Indexed: 12/13/2022] Open
Abstract
Life-threatening malignant arrhythmias in pathophysiological conditions can increase the mortality and morbidity of patients with cardiovascular diseases. Cardiac electrical activity depends on the coordinated propagation of excitatory stimuli and the generation of action potentials in cardiomyocytes. Action potential formation results from the opening and closing of ion channels. Recent studies have indicated that small-conductance calcium-activated potassium (SK) channels play a critical role in cardiac repolarization in pathophysiological but not normal physiological conditions. The aim of this review is to describe the role of SK channels in healthy and diseased hearts, to suggest cardiovascular pathophysiologic targets for intervention, and to discuss studies of agents that target SK channels for the treatment of cardiovascular diseases.
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Affiliation(s)
- Mingxia Gu
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Jiangsu, 210006, Nanjing, China
- Department of Cardiology, Nanjing Central Hospital, Jiangsu, 210018, Nanjing, China
| | - Yanrong Zhu
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Jiangsu, 210006, Nanjing, China
| | - Xiaorong Yin
- Department of Cardiology, Nanjing Central Hospital, Jiangsu, 210018, Nanjing, China
| | - Dai-Min Zhang
- Department of Cardiology, Nanjing First Hospital, Nanjing Medical University, Jiangsu, 210006, Nanjing, China.
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28
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Fu X, Pan Y, Cao Q, Li B, Wang S, Du H, Duan N, Li X. Metformin restores electrophysiology of small conductance calcium-activated potassium channels in the atrium of GK diabetic rats. BMC Cardiovasc Disord 2018; 18:63. [PMID: 29636010 PMCID: PMC5894224 DOI: 10.1186/s12872-018-0805-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/04/2018] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Small conductance calcium-activated potassium channels (SK channels) play a critical role in action potential repolarization in cardiomyocytes. Recently, the potential anti-arrhythmic effect of metformin in diabetic patients has been recognized, yet the underlying mechanism remains elusive. METHODS Diabetic Goto-Kakizaki (GK) rats were untreated or treated with metformin (300 mg/kg/day) for 12 weeks, and age-matched Wistar rats were used as control (n = 6 per group). Electrocardiography, Hematoxylin-eosin staining and Masson's trichome staining were performed to assess cardiac function, histology and fibrosis. The expression levels of the SK channels in the myocardium were determined by real-time PCR and Western blotting. The electrophysiology of the SK channels in the cardiomyocytes isolated from the three groups of rats was examined by patch clamp assay, with specific blockade of the SK channels with apamin. RESULTS Metformin treatment significantly reduced cardiac fibrosis and alleviated arrhythmia in the diabetic rats. In the atrial myocytes from control, GK and metformin-treated GK rats, the expression of KCa2.2 (SK2 channel) was down-regulated and the expression of KCa2.3 (SK3 channel) was up-regulated in the atrium of GK rats as compared with that of control rats, and metformin reversed diabetes-induced alterations in atrial SK channel expression. Moreover, patch clamp assay revealed that the SK current was markedly reduced and the action potential duration was prolonged in GK atrial myocytes, and the SK channel function was partially restored in the atrial myocytes from metformin-treated GK rats. CONCLUSIONS Our data suggests an involvement of the SK channels in the development of arrhythmia under diabetic conditions, and supports a potential beneficial effect of metformin on atrial electrophysiology.
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Affiliation(s)
- Xi Fu
- Department of Cardiology, Shengjing Hospital of China Medical University, Shenyang, 110004, People's Republic of China
| | - Yilong Pan
- Department of Cardiology, Shengjing Hospital of China Medical University, Shenyang, 110004, People's Republic of China
| | - Qian Cao
- Department of Cardiology, Shengjing Hospital of China Medical University, Shenyang, 110004, People's Republic of China
| | - Bin Li
- Department of Cardiology, Shengjing Hospital of China Medical University, Shenyang, 110004, People's Republic of China
| | - Shuo Wang
- Department of Cardiology, Shengjing Hospital of China Medical University, Shenyang, 110004, People's Republic of China
| | - Hongjiao Du
- Department of Cardiology, Shengjing Hospital of China Medical University, Shenyang, 110004, People's Republic of China
| | - Na Duan
- Department of Cardiology, The People's Hospital of Liaoning Province, Shenyang, 110016, People's Republic of China
| | - Xiaodong Li
- Department of Cardiology, Shengjing Hospital of China Medical University, Shenyang, 110004, People's Republic of China.
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Lu T, Wang XL, Chai Q, Sun X, Sieck GC, Katusic ZS, Lee HC. Role of the endothelial caveolae microdomain in shear stress-mediated coronary vasorelaxation. J Biol Chem 2017; 292:19013-19023. [PMID: 28924052 DOI: 10.1074/jbc.m117.786152] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 09/08/2017] [Indexed: 12/31/2022] Open
Abstract
In this study, we determined the role of caveolae and the ionic mechanisms that mediate shear stress-mediated vasodilation (SSD). We found that both TRPV4 and SK channels are targeted to caveolae in freshly isolated bovine coronary endothelial cells (BCECs) and that TRPV4 and KCa2.3 (SK3) channels are co-immunoprecipitated by anti-caveolin-1 antibodies. Acute exposure of BCECs seeded in a capillary tube to 10 dynes/cm2 of shear stress (SS) resulted in activation of TRPV4 and SK currents. However, after incubation with HC067047 (TRPV4 inhibitor), SK currents could no longer be activated by SS, suggesting SK channel activation by SS was mediated through TRPV4. SK currents in BCECs were also activated by isoproterenol or by GSK1016790A (TRPV4 activator). In addition, preincubation of isolated coronary arterioles with apamin (SK inhibitor) resulted in a significant diminution of SSD whereas preincubation with HC067047 produced vasoconstriction by SS. Exposure of BCECs to SS (15 dynes/cm2 16 h) enhanced the production of nitric oxide and prostacyclin (PGI2) and facilitated the translocation of TRPV4 to the caveolae. Inhibition of TRPV4 abolished the SS-mediated intracellular Ca2+ ([Ca2+] i ) increase in BCECs. These results indicate a dynamic interaction in the vascular endothelium among caveolae TRPV4 and SK3 channels. This caveolae-TRPV4-SK3 channel complex underlies the molecular and ionic mechanisms that modulate SSD in the coronary circulation.
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Affiliation(s)
- Tong Lu
- From the Department of Cardiovascular Medicine
| | | | - Qiang Chai
- From the Department of Cardiovascular Medicine.,the Department of Physiology, Institute of Basic Medicine, Shandong Academy of Medical Science, Jinan 250062, China
| | | | - Garry C Sieck
- Department of Physiology and Biomedical Engineering, and
| | - Zvonimir S Katusic
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota 55905 and
| | - Hon-Chi Lee
- From the Department of Cardiovascular Medicine,
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Howarth FC, Parekh K, Jayaprakash P, Inbaraj ES, Oz M, Dobrzynski H, Adrian TE. Altered profile of mRNA expression in atrioventricular node of streptozotocin‑induced diabetic rats. Mol Med Rep 2017; 16:3720-3730. [PMID: 28731153 PMCID: PMC5646948 DOI: 10.3892/mmr.2017.7038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 07/11/2017] [Indexed: 02/07/2023] Open
Abstract
Prolonged action potential duration, reduced action potential firing rate, upstroke velocity and rate of diastolic depolarization have been demonstrated in atrioventricular node (AVN) cells from streptozotocin (STZ)-induced diabetic rats. To further clarify the molecular basis of these electrical disturbances, the mRNA profiles encoding a variety of proteins associated with the generation and conduction of electrical activity in the AVN, were evaluated in the STZ-induced diabetic rat heart. Expression of mRNA was measured in AVN biopsies using reverse transcription-quantitative polymerase chain reaction techniques. Notable differences in mRNA expression included upregulation of genes encoding membrane and intracellular Ca2+ transport, including solute carrier family 8 member A1, transient receptor potential channel 1, ryanodine receptor 2/3, hyperpolarization-activated cyclic-nucleotide 2 and 3, calcium channel voltage-dependent, β2 subunit and sodium channels 3a, 4a, 7a and 3b. In addition to this, potassium channels potassium voltage-gated channel subfamily A member 4, potassium channel calcium activated intermediate/small conductance subfamily N α member 2, potassium voltage-gated channel subfamily J members 3, 5, and 11, potassium channel subfamily K members 1, 2, 3 and natriuretic peptide B (BNP) were upregulated in AVN of STZ heart, compared with controls. Alterations in gene expression were associated with upregulation of various proteins including the inwardly rectifying, potassium channel Kir3.4, NCX1 and BNP. The present study demonstrated notable differences in the profile of mRNA encoding proteins associated with the generation, conduction and regulation of electrical signals in the AVN of the STZ-induced diabetic rat heart. These data will provide a basis for a substantial range of future studies to investigate whether variations in mRNA translate into alterations in electrophysiological function.
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Affiliation(s)
- Frank Christopher Howarth
- Department of Physiology, College of Medicine and Health Sciences, UAE University, Al Ain 17666, United Arab Emirates
| | - Khatija Parekh
- Department of Physiology, College of Medicine and Health Sciences, UAE University, Al Ain 17666, United Arab Emirates
| | - Petrilla Jayaprakash
- Department of Physiology, College of Medicine and Health Sciences, UAE University, Al Ain 17666, United Arab Emirates
| | - Edward Samuel Inbaraj
- Department of Physiology, College of Medicine and Health Sciences, UAE University, Al Ain 17666, United Arab Emirates
| | - Murat Oz
- Department of Pharmacology, College of Medicine and Health Sciences, UAE University, Al Ain 17666, United Arab Emirates
| | - Halina Dobrzynski
- Institute of Cardiovascular Sciences, University of Manchester, Manchester M13 9NT, United Kingdom
| | - Thomas Edward Adrian
- Department of Physiology, College of Medicine and Health Sciences, UAE University, Al Ain 17666, United Arab Emirates
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Torrente AG, Zhang R, Wang H, Zaini A, Kim B, Yue X, Philipson KD, Goldhaber JI. Contribution of small conductance K + channels to sinoatrial node pacemaker activity: insights from atrial-specific Na + /Ca 2+ exchange knockout mice. J Physiol 2017; 595:3847-3865. [PMID: 28346695 DOI: 10.1113/jp274249] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 03/22/2017] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Repolarizing currents through K+ channels are essential for proper sinoatrial node (SAN) pacemaking, but the influence of intracellular Ca2+ on repolarization in the SAN is uncertain. We identified all three isoforms of Ca2+ -activated small conductance K+ (SK) channels in the murine SAN. SK channel blockade slows repolarization and subsequent depolarization of SAN cells. In the atrial-specific Na+ /Ca2+ exchanger (NCX) knockout mouse, cellular Ca2+ accumulation during spontaneous SAN pacemaker activity produces intermittent hyperactivation of SK channels, leading to arrhythmic pauses alternating with bursts of pacing. These findings suggest that Ca2+ -sensitive SK channels can translate changes in cellular Ca2+ into a repolarizing current capable of modulating pacemaking. SK channels are a potential pharmacological target for modulating SAN rate or treating SAN dysfunction, particularly under conditions characterized by abnormal increases in diastolic Ca2+ . ABSTRACT Small conductance K+ (SK) channels have been implicated as modulators of spontaneous depolarization and electrical conduction that may be involved in cardiac arrhythmia. However, neither their presence nor their contribution to sinoatrial node (SAN) pacemaker activity has been investigated. Using quantitative PCR (q-PCR), immunostaining and patch clamp recordings of membrane current and voltage, we identified all three SK isoforms (SK1, SK2 and SK3) in mouse SAN. Inhibition of SK channels with the specific blocker apamin prolonged action potentials (APs) in isolated SAN cells. Apamin also slowed diastolic depolarization and reduced pacemaker rate in isolated SAN cells and intact tissue. We investigated whether the Ca2+ -sensitive nature of SK channels could explain arrhythmic SAN pacemaker activity in the atrial-specific Na+ /Ca2+ exchange (NCX) knockout (KO) mouse, a model of cellular Ca2+ overload. SAN cells isolated from the NCX KO exhibited higher SK current than wildtype (WT) and apamin prolonged their APs. SK blockade partially suppressed the arrhythmic burst pacing pattern of intact NCX KO SAN tissue. We conclude that SK channels have demonstrable effects on SAN pacemaking in the mouse. Their Ca2+ -dependent activation translates changes in cellular Ca2+ into a repolarizing current capable of modulating regular pacemaking. This Ca2+ dependence also promotes abnormal automaticity when these channels are hyperactivated by elevated Ca2+ . We propose SK channels as a potential target for modulating SAN rate, and for treating patients affected by SAN dysfunction, particularly in the setting of Ca2+ overload.
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Affiliation(s)
- Angelo G Torrente
- Cedars-Sinai Heart Institute, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Rui Zhang
- Cedars-Sinai Heart Institute, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Heidi Wang
- Cedars-Sinai Heart Institute, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Audrey Zaini
- Cedars-Sinai Heart Institute, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Brian Kim
- Cedars-Sinai Heart Institute, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Xin Yue
- Cedars-Sinai Heart Institute, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
| | - Kenneth D Philipson
- Department of Physiology, David Geffen School of Medicine at UCLA, 650 Charles Young Drive South, Los Angeles, CA, 90095-1751, USA
| | - Joshua I Goldhaber
- Cedars-Sinai Heart Institute, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA.,Department of Biomedical Sciences, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA
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Voos P, Yazar M, Lautenschläger R, Rauh O, Moroni A, Thiel G. The small neurotoxin apamin blocks not only small conductance Ca 2+ activated K + channels (SK type) but also the voltage dependent Kv1.3 channel. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017; 46:517-523. [PMID: 28108814 DOI: 10.1007/s00249-016-1196-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 12/12/2016] [Accepted: 12/30/2016] [Indexed: 11/29/2022]
Abstract
Apamin is frequently used as a specific blocker of small-conductance Ca2+-activated (SK type) K+ channels. Here we show that the small neurotoxin is not as specific as anticipated. It is also a high-affinity inhibitor with an IC50 of 13 nM of the Kv1.3 channel; it blocks the latter with potency similar to the Kv1.3 blocker PAP-1. Since SK type channels and Kv1.3 channels are frequently coexpressed in different tissues such as cells of the immune system, apamin must be used with caution as a pharmacological tool.
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Affiliation(s)
- Patrick Voos
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany
| | - Mehtap Yazar
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany
| | - René Lautenschläger
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany
| | - Oliver Rauh
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany
| | - Anna Moroni
- Department of Biology and CNR IBF-Mi, Università degli Studi di Milano, Milan, Italy
| | - Gerhard Thiel
- Department of Biology, Plant Membrane Biophysics, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany.
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Yu CC, Chia-Ti T, Chen PL, Wu CK, Chiu FC, Chiang FT, Chen PS, Chen CL, Lin LY, Juang JM, Ho LT, Lai LP, Yang WS, Lin JL. KCNN2 polymorphisms and cardiac tachyarrhythmias. Medicine (Baltimore) 2016; 95:e4312. [PMID: 27442679 PMCID: PMC5265796 DOI: 10.1097/md.0000000000004312] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Potassium calcium-activated channel subfamily N member 2 (KCNN2) encodes an integral membrane protein that forms small-conductance calcium-activated potassium (SK) channels. Recent studies in animal models show that SK channels are important in atrial and ventricular repolarization and arrhythmogenesis. However, the importance of SK channels in human arrhythmia remains unclear. The purpose of the present study was to test the association between genetic polymorphism of the SK2 channel and the occurrence of cardiac tachyarrhythmias in humans. We enrolled 327 Han Chinese, including 72 with clinically significant ventricular tachyarrhythmias (VTa) who had a history of aborted sudden cardiac death (SCD) or unexplained syncope, 98 with a history of atrial fibrillation (AF), and 144 normal controls. We genotyped 12 representative tag single nucleotide polymorphisms (SNPs) across a 141-kb genetic region containing the KCNN2 gene; these captured the full haplotype information. The rs13184658 and rs10076582 variants of KCNN2 were associated with VTa in both the additive and dominant models (odds ratio [OR] 2.89, 95% confidence interval [CI] = 1.505-5.545, P = 0.001; and OR 2.55, 95% CI = 1.428-4.566, P = 0.002, respectively). After adjustment for potential risk factors, the association remained significant. The population attributable risks of these 2 variants of VTa were 17.3% and 10.6%, respectively. One variant (rs13184658) showed weak but significant association with AF in a dominant model (OR 1.91, CI = 1.025-3.570], P = 0.042). There was a significant association between the KCNN2 variants and clinically significant VTa. These findings suggest an association between KCNN2 and VTa; it also appears that KCNN2 variants may be adjunctive markers for risk stratification in patients susceptible to SCD.
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Affiliation(s)
- Chih-Chieh Yu
- Department of Internal Medicine, National Taiwan University Hospital
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
| | - Tsai Chia-Ti
- Department of Internal Medicine, National Taiwan University Hospital
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
| | - Pei-Lung Chen
- Department of Internal Medicine, National Taiwan University Hospital
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
- Department of Medical Genetics, National Taiwan University Hospital
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine
- Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei
| | - Cho-Kai Wu
- Department of Internal Medicine, National Taiwan University Hospital
| | - Fu-Chun Chiu
- Department of Internal Medicine, National Taiwan University Hospital, Yun-Lin Branch, Yun-Lin, Taiwan
| | - Fu-Tien Chiang
- Department of Internal Medicine, National Taiwan University Hospital
| | - Peng-Sheng Chen
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Chi-Ling Chen
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
- Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Lian-Yu Lin
- Department of Internal Medicine, National Taiwan University Hospital
| | - Jyh-Ming Juang
- Department of Internal Medicine, National Taiwan University Hospital
| | - Li-Ting Ho
- Department of Internal Medicine, National Taiwan University Hospital
| | - Ling-Ping Lai
- Department of Internal Medicine, National Taiwan University Hospital
| | - Wei-Shiung Yang
- Department of Internal Medicine, National Taiwan University Hospital
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine
- Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei
- Correspondence: Jiunn-Lee Lin, Wei-Shiung Yang, Department of Internal Medicine, National Taiwan University Hospital, No. 7, Chung San South Road, Taipei City 100, Taiwan (R.O.C.) (e-mail: , )
| | - Jiunn-Lee Lin
- Department of Internal Medicine, National Taiwan University Hospital
- Correspondence: Jiunn-Lee Lin, Wei-Shiung Yang, Department of Internal Medicine, National Taiwan University Hospital, No. 7, Chung San South Road, Taipei City 100, Taiwan (R.O.C.) (e-mail: , )
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Hancox JC, James AF, Marrion NV, Zhang H, Thomas D. Novel ion channel targets in atrial fibrillation. Expert Opin Ther Targets 2016; 20:947-58. [DOI: 10.1517/14728222.2016.1159300] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, University Walk, Bristol, UK
| | - Andrew F. James
- School of Physiology, Pharmacology and Neuroscience, University Walk, Bristol, UK
| | - Neil V. Marrion
- School of Physiology, Pharmacology and Neuroscience, University Walk, Bristol, UK
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Dierk Thomas
- Department of Cardiology, University of Heidelberg, Heidelberg, Germany
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Ohya S, Kito H, Hatano N, Muraki K. Recent advances in therapeutic strategies that focus on the regulation of ion channel expression. Pharmacol Ther 2016; 160:11-43. [PMID: 26896566 DOI: 10.1016/j.pharmthera.2016.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A number of different ion channel types are involved in cell signaling networks, and homeostatic regulatory mechanisms contribute to the control of ion channel expression. Profiling of global gene expression using microarray technology has recently provided novel insights into the molecular mechanisms underlying the homeostatic and pathological control of ion channel expression. It has demonstrated that the dysregulation of ion channel expression is associated with the pathogenesis of neural, cardiovascular, and immune diseases as well as cancers. In addition to the transcriptional, translational, and post-translational regulation of ion channels, potentially important evidence on the mechanisms controlling ion channel expression has recently been accumulated. The regulation of alternative pre-mRNA splicing is therefore a novel therapeutic strategy for the treatment of dominant-negative splicing disorders. Epigenetic modification plays a key role in various pathological conditions through the regulation of pluripotency genes. Inhibitors of pre-mRNA splicing and histone deacetyalase/methyltransferase have potential as potent therapeutic drugs for cancers and autoimmune and inflammatory diseases. Moreover, membrane-anchoring proteins, lysosomal and proteasomal degradation-related molecules, auxiliary subunits, and pharmacological agents alter the protein folding, membrane trafficking, and post-translational modifications of ion channels, and are linked to expression-defect channelopathies. In this review, we focused on recent insights into the transcriptional, spliceosomal, epigenetic, and proteasomal regulation of ion channel expression: Ca(2+) channels (TRPC/TRPV/TRPM/TRPA/Orai), K(+) channels (voltage-gated, KV/Ca(2+)-activated, KCa/two-pore domain, K2P/inward-rectifier, Kir), and Ca(2+)-activated Cl(-) channels (TMEM16A/TMEM16B). Furthermore, this review highlights expression of these ion channels in expression-defect channelopathies.
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Affiliation(s)
- Susumu Ohya
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan.
| | - Hiroaki Kito
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Kyoto 607-8414, Japan
| | - Noriyuki Hatano
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan
| | - Katsuhiko Muraki
- Laboratory of Cellular Pharmacology, School of Pharmacy, Aichi-Gakuin University, Nagoya 464-8650, Japan.
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RamaKrishnan AM, Sankaranarayanan K. Understanding autoimmunity: The ion channel perspective. Autoimmun Rev 2016; 15:585-620. [PMID: 26854401 DOI: 10.1016/j.autrev.2016.02.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 01/29/2016] [Indexed: 12/11/2022]
Abstract
Ion channels are integral membrane proteins that orchestrate the passage of ions across the cell membrane and thus regulate various key physiological processes of the living system. The stringently regulated expression and function of these channels hold a pivotal role in the development and execution of various cellular functions. Malfunction of these channels results in debilitating diseases collectively termed channelopathies. In this review, we highlight the role of these proteins in the immune system with special emphasis on the development of autoimmunity. The role of ion channels in various autoimmune diseases is also listed out. This comprehensive review summarizes the ion channels that could be used as molecular targets in the development of new therapeutics against autoimmune disorders.
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Affiliation(s)
| | - Kavitha Sankaranarayanan
- AU-KBC Research Centre, Madras Institute of Technology, Anna University, Chrompet, Chennai 600 044, India.
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Tse G, Lai ETH, Tse V, Yeo JM. Molecular and Electrophysiological Mechanisms Underlying Cardiac Arrhythmogenesis in Diabetes Mellitus. J Diabetes Res 2016; 2016:2848759. [PMID: 27642609 PMCID: PMC5011530 DOI: 10.1155/2016/2848759] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 04/28/2016] [Indexed: 01/11/2023] Open
Abstract
Diabetes is a common endocrine disorder with an ever increasing prevalence globally, placing significant burdens on our healthcare systems. It is associated with significant cardiovascular morbidities. One of the mechanisms by which it causes death is increasing the risk of cardiac arrhythmias. The aim of this article is to review the cardiac (ion channel abnormalities, electrophysiological and structural remodelling) and extracardiac factors (neural pathway remodelling) responsible for cardiac arrhythmogenesis in diabetes. It is concluded by an outline of molecular targets for future antiarrhythmic therapy for the diabetic population.
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Affiliation(s)
- Gary Tse
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Shatin, Hong Kong
- *Gary Tse:
| | - Eric Tsz Him Lai
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong
| | - Vivian Tse
- Department of Physiology, McGill University, Montreal, QC, Canada H3G 1Y6
| | - Jie Ming Yeo
- School of Medicine, Imperial College London, London SW7 2AZ, UK
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Calcium-Activated Potassium Channels: Potential Target for Cardiovascular Diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 104:233-261. [PMID: 27038376 DOI: 10.1016/bs.apcsb.2015.11.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Ca(2+)-activated K(+) channels (KCa) are classified into three subtypes: big conductance (BKCa), intermediate conductance (IKCa), and small conductance (SKCa) KCa channels. The three types of KCa channels have distinct physiological or pathological functions in cardiovascular system. BKCa channels are mainly expressed in vascular smooth muscle cells (VSMCs) and inner mitochondrial membrane of cardiomyocytes, activation of BKCa channels in these locations results in vasodilation and cardioprotection against cardiac ischemia. IKCa channels are expressed in VSMCs, endothelial cells, and cardiac fibroblasts and involved in vascular smooth muscle proliferation, migration, vessel dilation, and cardiac fibrosis. SKCa channels are widely expressed in nervous and cardiovascular system, and activation of SKCa channels mainly contributes membrane hyperpolarization. In this chapter, we summarize the physiological and pathological roles of the three types of KCa channels in cardiovascular system and put forward the possibility of KCa channels as potential target for cardiovascular diseases.
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Hu XQ, Huang X, Xiao D, Zhang L. Direct effect of chronic hypoxia in suppressing large conductance Ca(2+)-activated K(+) channel activity in ovine uterine arteries via increasing oxidative stress. J Physiol 2015; 594:343-56. [PMID: 26613808 DOI: 10.1113/jp271626] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 11/24/2015] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS Chronic hypoxia has a direct effect in down-regulating the BKCa channel β1 subunit and inhibiting the BKCa channel activity in uterine arteries of pregnant sheep. Oxidative stress plays a causal role in hypoxia-mediated suppression of BKCa channel function. The steroid hormone-induced effect on BKCa channels is a target of hypoxia-mediated oxidative stress. Inhibition of oxidative stress ameliorates the adverse effect of hypoxia both ex vivo and in vivo in pregnant sheep exposed to long-term high-altitude hypoxia. Our findings provide novel evidence of a causative role of oxidative stress in hypoxia-mediated inhibition of the BKCa channel activity in uterine arteries and new insights in understanding and alleviating pregnancy complications associated with gestational hypoxia such as pre-eclampsia and fetal growth restriction. ABSTRACT Uterine arteries of pregnant sheep acclimatized to long-term high-altitude hypoxia were associated with a decrease in large-conductance Ca(2+)-activated K(+) (BKCa) channel activity. The present study tested the hypothesis that prolonged hypoxia has a direct effect in suppressing BKCa channel activity by increasing oxidative stress. Uterine arteries were isolated from non-pregnant and near-term (∼142 days) pregnant sheep, and were treated ex vivo with 21.0 or 10.5% O2 for 48 h. The hypoxia treatment significantly increased the production of reactive oxygen species in uterine arteries, which was blocked by N-acetylcysteine. In uterine arteries of pregnant sheep, hypoxia significantly inhibited BKCa channel current density, decreased NS1619-induced relaxations and increased pressure-dependent tone, which were annulled by N-acetylcysteine. In accordance, hypoxia resulted in down-regulation of BKCa channel β1 subunit, which was restored in the presence of N-acetylcysteine. In addition, the N-acetylcysteine treatment significantly increased BKCa channel β1 subunit abundance and BKCa channel current density in uterine arteries from pregnant sheep exposed to high-altitude hypoxia (3801 m, PaO2: 60 mmHg) for 110 days. In uterine arteries of non-pregnant animals, hypoxia inhibited steroid hormone-induced up-regulation of BKCa channel current density and NS1619-mediated relaxations, which were reversed by N-acetylcysteine. Furthermore, the synthetic superoxide dismutase and catalase mimetic EUK-134 also ablated the effects of hypoxia on BKCa channel currents in uterine arteries. The results demonstrate a direct effect of hypoxia in inhibiting the BKCa channel activity in uterine arteries via increased oxidative stress.
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Affiliation(s)
- Xiang-Qun Hu
- Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California, USA
| | - Xiaohui Huang
- Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California, USA
| | - Daliao Xiao
- Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California, USA
| | - Lubo Zhang
- Center for Perinatal Biology, Division of Pharmacology, Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California, USA
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Grunnet M. Cardiac SK channels: Friend or foe? Heart Rhythm 2015; 12:1016-7. [PMID: 25678058 DOI: 10.1016/j.hrthm.2015.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Indexed: 10/24/2022]
Affiliation(s)
- Morten Grunnet
- Acesion Pharma A/S and Institute for Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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