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Shugg T, Hudmon A, Overholser BR. Neurohormonal Regulation of I Ks in Heart Failure: Implications for Ventricular Arrhythmogenesis and Sudden Cardiac Death. J Am Heart Assoc 2020; 9:e016900. [PMID: 32865116 PMCID: PMC7726975 DOI: 10.1161/jaha.120.016900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Heart failure (HF) results in sustained alterations in neurohormonal signaling, including enhanced signaling through the sympathetic nervous system and renin-angiotensin-aldosterone system pathways. While enhanced sympathetic nervous system and renin-angiotensin-aldosterone system activity initially help compensate for the failing myocardium, sustained signaling through these pathways ultimately contributes to HF pathophysiology. HF remains a leading cause of mortality, with arrhythmogenic sudden cardiac death comprising a common mechanism of HF-related death. The propensity for arrhythmia development in HF occurs secondary to cardiac electrical remodeling that involves pathological regulation of ventricular ion channels, including the slow component of the delayed rectifier potassium current, that contribute to action potential duration prolongation. To elucidate a mechanistic explanation for how HF-mediated electrical remodeling predisposes to arrhythmia development, a multitude of investigations have investigated the specific regulatory effects of HF-associated stimuli, including enhanced sympathetic nervous system and renin-angiotensin-aldosterone system signaling, on the slow component of the delayed rectifier potassium current. The objective of this review is to summarize the current knowledge related to the regulation of the slow component of the delayed rectifier potassium current in response to HF-associated stimuli, including the intracellular pathways involved and the specific regulatory mechanisms.
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Affiliation(s)
- Tyler Shugg
- Division of Clinical PharmacologyIndiana University School of MedicineIndianapolisIN
| | - Andy Hudmon
- Department of Medicinal Chemistry and Molecular PharmacologyPurdue University College of PharmacyWest LafayetteIN
| | - Brian R. Overholser
- Division of Clinical PharmacologyIndiana University School of MedicineIndianapolisIN
- Department of Pharmacy PracticePurdue University College of PharmacyIndianapolisIN
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Long QQ, Wang H, Gao W, Fan Y, Li YF, Ma Y, Yang Y, Shi HJ, Chen BR, Meng HY, Wang QM, Wang F, Wang ZM, Wang LS. Long Noncoding RNA Kcna2 Antisense RNA Contributes to Ventricular Arrhythmias via Silencing Kcna2 in Rats With Congestive Heart Failure. J Am Heart Assoc 2017; 6:JAHA.117.005965. [PMID: 29263036 PMCID: PMC5778995 DOI: 10.1161/jaha.117.005965] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Congestive heart failure (CHF) is a common cardiovascular disease that is often accompanied by ventricular arrhythmias. The decrease of the slow component of the delayed rectifier potassium current (IKs) in CHF leads to action potential (AP) prolongation, and the IKs is an important contributor to the development of ventricular arrhythmias. However, the molecular mechanisms underlying ventricular arrhythmias are still unknown. METHODS AND RESULTS Kcna2 and Kcna2 antisense RNA (Kcna2 AS) transcript expression was measured in rat cardiac tissues using quantitative real-time reverse transcription-polymerase chain reaction and Western blotting. There was a 43% reduction in Kcna2 mRNA in the left ventricular myocardium of rats with CHF. Kcna2 knockdown in the heart decreased the IKs and prolonged APs in cardiomyocytes, consistent with the changes observed in heart failure. Conversely, Kcna2 overexpression in the heart significantly attenuated the CHF-induced decreases in the IKs, AP prolongation, and ventricular arrhythmias. Kcna2 AS was upregulated ≈1.7-fold in rats with CHF and with phenylephrine-induced cardiomyocyte hypertrophy. Kcna2 AS inhibition increased the CHF-induced downregulation of Kcna2. Consequently, Kcna2 AS mitigated the decrease in the IKs and the prolongation of APs in vivo and in vitro and reduced ventricular arrhythmias, as detected using electrocardiography. CONCLUSIONS Ventricular Kcna2 AS expression increases in rats with CHF and contributes to reduced IKs, prolonged APs, and the occurrence of ventricular arrhythmias by silencing Kcna2. Thus, Kcna2 AS may be a new target for the prevention and treatment of ventricular arrhythmias in patients with CHF.
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Affiliation(s)
- Qing-Qing Long
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hao Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Wei Gao
- Department of Geriatrics, Sir Run Run Hospital of Nanjing Medical University, Nanjing, China
| | - Yi Fan
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ya-Fei Li
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yao Ma
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yang Yang
- Department of Emergency and Intensive Care, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hao-Jie Shi
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Bing-Rui Chen
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Hao-Yu Meng
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Qi-Ming Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Fang Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ze-Mu Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Lian-Sheng Wang
- Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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Lee HC, Rudy Y, Liang H, Chen CC, Luo CH, Sheu SH, Cui J. Pro-arrhythmogenic Effects of the V141M KCNQ1 Mutation in Short QT Syndrome and Its Potential Therapeutic Targets: Insights from Modeling. J Med Biol Eng 2017; 37:780-789. [PMID: 29213224 PMCID: PMC5714284 DOI: 10.1007/s40846-017-0257-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Gain-of-function mutations in the pore-forming subunit of IKs channels, KCNQ1, lead to short QT syndrome (SQTS) and lethal arrhythmias. However, how mutant IKs channels cause SQTS and the possibility of IKs-specific pharmacological treatment remain unclear. V141M KCNQ1 is a SQTS associated mutation. We studied its effect on IKs gating properties and changes in the action potentials (AP) of human ventricular myocytes. Xenopus oocytes were used to study the gating mechanisms of expressed V141M KCNQ1/KCNE1 channels. Computational models were used to simulate human APs in endocardial, mid-myocardial, and epicardial ventricular myocytes with and without β-adrenergic stimulation. V141M KCNQ1 caused a gain-of-function in IKs characterized by increased current density, faster activation, and slower deactivation leading to IKs accumulation. V141M KCNQ1 also caused a leftward shift of the conductance-voltage curve compared to wild type (WT) IKs (V1/2 = 33.6 ± 4.0 mV for WT, and 24.0 ± 1.3 mV for heterozygous V141M). A Markov model of heterozygous V141M mutant IKs was developed and incorporated into the O’Hara–Rudy model. Compared to the WT, AP simulations demonstrated marked rate-dependent shortening of AP duration (APD) for V141M, predicting a SQTS phenotype. Transmural electrical heterogeneity was enhanced in heterozygous V141M AP simulations, especially under β-adrenergic stimulation. Computational simulations identified specific IK1 blockade as a beneficial pharmacologic target for reducing the transmural APD heterogeneity associated with V141M KCNQ1 mutation. V141M KCNQ1 mutation shortens ventricular APs and enhances transmural APD heterogeneity under β-adrenergic stimulation. Computational simulations identified IK1 blockers as a potential antiarrhythmic drug of choice for SQTS.
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Affiliation(s)
- Hsiang-Chun Lee
- Cardiac Bioelectricity and Arrhythmia Center, Washington University in St. Louis, St. Louis, MO 63130, USA.,Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, 100 Tzyou 1st Rd, Kaohsiung 807, Taiwan.,Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.,Center for Lipid Biosciences, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan.,Lipid Science and Aging Research Center, Kaohsiung Medical University, Kaohsiung 807, Taiwan.,Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Yoram Rudy
- Cardiac Bioelectricity and Arrhythmia Center, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Hongwu Liang
- Cardiac Bioelectricity and Arrhythmia Center, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Chih-Chieh Chen
- Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Ching-Hsing Luo
- Department of Electric Engineering, National Cheng Kung University, Tainan 804, Taiwan
| | - Sheng-Hsiung Sheu
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, 100 Tzyou 1st Rd, Kaohsiung 807, Taiwan.,Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.,Center for Lipid Biosciences, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Jianmin Cui
- Cardiac Bioelectricity and Arrhythmia Center, Washington University in St. Louis, St. Louis, MO 63130, USA
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Lee HC, Chiu CC, Chen CC, Huang JW, Lin HT, Hsiao YL, Sheu SH, Hsieh CC. Modulation of potassium channel KCNQ1 transcript in right atrial appendage of patients with postoperative atrial fibrillation. Int J Cardiol 2016; 222:696-698. [PMID: 27521539 DOI: 10.1016/j.ijcard.2016.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 08/02/2016] [Indexed: 11/25/2022]
Affiliation(s)
- Hsiang-Chun Lee
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan; Department of Internal Medicine, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Center for Lipid Biosciences, Kaohsiung Medical University Hospital, Taiwan; Lipid Science and Aging Research Center, Kaohsiung Medical University, Taiwan; Institute/Center of Medical Science and Technology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - Chaw-Chi Chiu
- Department of Chest Surgery, Division of Cardiovascular Surgery and Department of Surgery, Kaohsiung Medical University Hospital, Taiwan
| | - Chiu-Chen Chen
- Department of Chest Surgery, Division of Cardiovascular Surgery and Department of Surgery, Kaohsiung Medical University Hospital, Taiwan
| | - Jiann-Woei Huang
- Department of Chest Surgery, Division of Cardiovascular Surgery and Department of Surgery, Kaohsiung Medical University Hospital, Taiwan
| | - Hsin-Ting Lin
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan; Center for Lipid Biosciences, Kaohsiung Medical University Hospital, Taiwan; Lipid Science and Aging Research Center, Kaohsiung Medical University, Taiwan
| | - Yi-Lin Hsiao
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan; Center for Lipid Biosciences, Kaohsiung Medical University Hospital, Taiwan; Lipid Science and Aging Research Center, Kaohsiung Medical University, Taiwan
| | - Sheng-Hsiung Sheu
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan; Department of Internal Medicine, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan; Department of Internal Medicine, St. Joseph Hospital, Kaohsiung, Taiwan
| | - Chong-Chao Hsieh
- Department of Chest Surgery, Division of Cardiovascular Surgery and Department of Surgery, Kaohsiung Medical University Hospital, Taiwan.
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McKinnon D, Rosati B. Transmural gradients in ion channel and auxiliary subunit expression. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 122:165-186. [PMID: 27702655 DOI: 10.1016/j.pbiomolbio.2016.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/30/2016] [Indexed: 12/11/2022]
Abstract
Evolution has acted to shape the action potential in different regions of the heart in order to produce a maximally stable and efficient pump. This has been achieved by creating regional differences in ion channel expression levels within the heart as well as differences between equivalent cardiac tissues in different species. These region- and species-dependent differences in channel expression are established by regulatory evolution, evolution of the regulatory mechanisms that control channel expression levels. Ion channel auxiliary subunits are obvious targets for regulatory evolution, in order to change channel expression levels and/or modify channel function. This review focuses on the transmural gradients of ion channel expression in the heart and the role that regulation of auxiliary subunit expression plays in generating and shaping these gradients.
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Affiliation(s)
- David McKinnon
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Barbara Rosati
- Department of Veterans Affairs Medical Center, Northport, NY, USA; Institute of Molecular Cardiology, Stony Brook University, Stony Brook, NY, USA; Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, 11794, USA.
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The Effects of Puerarin on Rat Ventricular Myocytes and the Potential Mechanism. Sci Rep 2016; 6:35475. [PMID: 27762288 PMCID: PMC5071873 DOI: 10.1038/srep35475] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 09/28/2016] [Indexed: 12/22/2022] Open
Abstract
Puerarin, a known isoflavone, is commonly found as a Chinese herb medicine. It is widely used in China to treat cardiac diseases such as angina, cardiac infarction and arrhythmia. However, its cardioprotective mechanism remains unclear. In this study, puerarin significantly prolonged ventricular action potential duration (APD) with a dosage dependent manner in the micromolar range on isolated rat ventricular myocytes. However, submicromolar puerarin had no effect on resting membrane potential (RMP), action potential amplitude (APA) and maximal velocity of depolarization (Vmax) of action potential. Only above the concentration of 10 mM, puerarin exhibited more aggressive effect on action potential, and shifted RMP to the positive direction. Millimolar concentrations of puerarin significantly inhibited inward rectified K+ channels in a dosage dependent manner, and exhibited bigger effects upon Kir2.1 vs Kir2.3 in transfected HEK293 cells. As low as micromolar range concentrations of puerarin significantly inhibited Kv7.1 and IKs. These inhibitory effects may due to the direct inhibition of puerarin upon channels not via the PKA-dependent pathway. These results provided direct preclinical evidence that puerarin prolonged APD via its inhibitory effect upon Kv7.1 and IKs, contributing to a better understanding the mechanism of puerarin cardioprotection in the treatment of cardiovascular diseases.
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Abstract
Optimal cardiac function depends on proper timing of excitation and contraction in various regions of the heart, as well as on appropriate heart rate. This is accomplished via specialized electrical properties of various components of the system, including the sinoatrial node, atria, atrioventricular node, His-Purkinje system, and ventricles. Here we review the major regionally determined electrical properties of these cardiac regions and present the available data regarding the molecular and ionic bases of regional cardiac function and dysfunction. Understanding these differences is of fundamental importance for the investigation of arrhythmia mechanisms and pharmacotherapy.
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Affiliation(s)
- Daniel C Bartos
- Department of Pharmacology, University of California Davis, Davis, California, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, California, USA
| | - Crystal M Ripplinger
- Department of Pharmacology, University of California Davis, Davis, California, USA
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Schmitt N, Grunnet M, Olesen SP. Cardiac potassium channel subtypes: new roles in repolarization and arrhythmia. Physiol Rev 2014; 94:609-53. [PMID: 24692356 DOI: 10.1152/physrev.00022.2013] [Citation(s) in RCA: 160] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K+ channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K+ channels drive the late repolarization of the ventricle with some redundancy, and in atria this repolarization reserve is supplemented by the fairly atrial-specific KV1.5, Kir3, KCa, and K2P channels. The role of the latter two subtypes in atria is currently being clarified, and several findings indicate that they could constitute targets for new pharmacological treatment of atrial fibrillation. The interplay between the different K+ channel subtypes in both atria and ventricle is dynamic, and a significant up- and downregulation occurs in disease states such as atrial fibrillation or heart failure. The underlying posttranscriptional and posttranslational remodeling of the individual K+ channels changes their activity and significance relative to each other, and they must be viewed together to understand their role in keeping a stable heart rhythm, also under menacing conditions like attacks of reentry arrhythmia.
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Heijman J, Voigt N, Carlsson LG, Dobrev D. Cardiac safety assays. Curr Opin Pharmacol 2014; 15:16-21. [DOI: 10.1016/j.coph.2013.11.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Revised: 11/04/2013] [Accepted: 11/07/2013] [Indexed: 12/22/2022]
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Skinner JR, Waddell-Smith K, Anderson BJ. To the editor- amiloride concentrations in clinical practice. Heart Rhythm 2013; 10:e82-3. [PMID: 24055945 DOI: 10.1016/j.hrthm.2013.09.056] [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: 09/03/2013] [Indexed: 11/24/2022]
Affiliation(s)
- Jonathan R Skinner
- Green Lane Paediatric and Congenital Cardiac Services Starship Children's' Hospital Auckland, New Zealand; University of Auckland Auckland, New Zealand.
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Thomsen MB. Kv7.1 isoform gradients in the heart: new potential approach to alter repolarization reserve. Heart Rhythm 2013; 10:1229-30. [PMID: 23806322 DOI: 10.1016/j.hrthm.2013.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Indexed: 10/26/2022]
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