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Zhuang Z, Li Y, Zhao Y, Huang N, Wang W, Xiao W, Du J, Dong X, Song Z, Jia J, Liu Z, Clarke R, Qi L, Huang T. Genetically determined blood pressure, antihypertensive drug classes, and frailty: A Mendelian randomization study. Aging Cell 2024; 23:e14173. [PMID: 38725159 PMCID: PMC11258474 DOI: 10.1111/acel.14173] [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: 10/08/2023] [Revised: 03/06/2024] [Accepted: 03/24/2024] [Indexed: 07/21/2024] Open
Abstract
Observational studies have suggested that the use of antihypertensive drugs was associated with the risk of frailty; however, these findings may be biased by confounding and reverse causality. This study aimed to explore the effect of genetically predicted lifelong lowering blood pressure (BP) through different antihypertensive medications on frailty. One-sample Mendelian randomization (MR) and summary data-based MR (SMR) were applied. We utilized two kinds of genetic instruments to proxy the antihypertensive medications, including genetic variants within or nearby drugs target genes associated with systolic/diastolic BP, and expression level of the corresponding gene. Among 298,618 UK Biobank participants, one-sample MR analysis observed that genetically proxied BB use (relative risk ratios, 0.76; 95% CI, 0.65-0.90; p = 0.001) and CCB use (0.83; 0.72-0.95; p = 0.007), equivalent to a 10-mm Hg reduction in systolic BP, was significantly associated with lower risk of pre-frailty. In addition, although not statistically significant, the effect directions of systolic BP through ACEi variants (0.72; 0.39-1.33; p = 0.296) or thiazides variants (0.74; 0.53-1.03; p = 0.072) on pre-frailty were also protective. Similar results were obtained in analyses for diastolic BP. SMR of expression in artery showed that decreased expression level of KCNH2, a target gene of BBs, was associated with lower frailty index (beta -0.02, p = 2.87 × 10-4). This MR analysis found evidence that the use of BBs and CCBs was potentially associated with reduced frailty risk in the general population, and identified KCNH2 as a promising target for further clinical trials to prevent manifestations of frailty.
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Affiliation(s)
- Zhenhuang Zhuang
- Department of Epidemiology and Biostatistics, School of Public HealthPeking UniversityBeijingChina
| | - Yueying Li
- Department of Epidemiology and Biostatistics, School of Public HealthPeking UniversityBeijingChina
| | - Yimin Zhao
- Department of Epidemiology and Biostatistics, School of Public HealthPeking UniversityBeijingChina
| | - Ninghao Huang
- Department of Epidemiology and Biostatistics, School of Public HealthPeking UniversityBeijingChina
| | - Wenxiu Wang
- Department of Epidemiology and Biostatistics, School of Public HealthPeking UniversityBeijingChina
| | - Wendi Xiao
- Department of Epidemiology and Biostatistics, School of Public HealthPeking UniversityBeijingChina
| | - Jie Du
- National Institute for Nutrition and HealthChinese Center for Diseases Control and PreventionBeijingChina
| | - Xue Dong
- Department of Epidemiology and Biostatistics, School of Public HealthPeking UniversityBeijingChina
| | - Zimin Song
- Department of Epidemiology and Biostatistics, School of Public HealthPeking UniversityBeijingChina
| | - Jinzhu Jia
- Department of Biostatistics, School of Public HealthPeking UniversityBeijingChina
| | - Zhonghua Liu
- Department of BiostatisticsColumbia UniversityNew YorkNew YorkUSA
| | - Robert Clarke
- Clinical Trial Service Unit and Epidemiological Studies Unit (CTSU), Nuffield Department of Population HealthUniversity of OxfordOxfordUK
| | - Lu Qi
- Department of Epidemiology, School of Public Health and Tropical MedicineTulane UniversityNew OrleansLouisianaUSA
- Department of NutritionHarvard T.H. Chan School of Public HealthBostonMassachusettsUSA
| | - Tao Huang
- Department of Epidemiology and Biostatistics, School of Public HealthPeking UniversityBeijingChina
- Key Laboratory of Epidemiology of Major Diseases (Peking University)Ministry of EducationBeijingChina
- Center for Intelligent Public Health, Academy for Artificial IntelligencePeking UniversityBeijingChina
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Zhao Z, Zang X, Niu K, Song W, Wang X, Mügge A, Aweimer A, Hamdani N, Zhou X, Zhao Y, Akin I, El-Battrawy I. Impacts of gene variants on drug effects-the foundation of genotype-guided pharmacologic therapy for long QT syndrome and short QT syndrome. EBioMedicine 2024; 103:105108. [PMID: 38653189 PMCID: PMC11041837 DOI: 10.1016/j.ebiom.2024.105108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 03/20/2024] [Accepted: 03/24/2024] [Indexed: 04/25/2024] Open
Abstract
The clinical significance of optimal pharmacotherapy for inherited arrhythmias such as short QT syndrome (SQTS) and long QT syndrome (LQTS) has been increasingly recognised. The advancement of gene technology has opened up new possibilities for identifying genetic variations and investigating the pathophysiological roles and mechanisms of genetic arrhythmias. Numerous variants in various genes have been proven to be causative in genetic arrhythmias. Studies have demonstrated that the effectiveness of certain drugs is specific to the patient or genotype, indicating the important role of gene-variants in drug response. This review aims to summarize the reported data on the impact of different gene-variants on drug response in SQTS and LQTS, as well as discuss the potential mechanisms by which gene-variants alter drug response. These findings may provide valuable information for future studies on the influence of gene variants on drug efficacy and the development of genotype-guided or precision treatment for these diseases.
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Affiliation(s)
- Zhihan Zhao
- Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, China
| | - Xiaobiao Zang
- Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, China
| | - Kerun Niu
- Department of Orthopaedic, Henan Provincial People's Hospital; Zhengzhou University People's Hospital, Zhengzhou, Henan, 450003, China
| | - Weifeng Song
- Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, China
| | - Xianqing Wang
- Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, China
| | - Andreas Mügge
- Department of Cardiology and Angiology, Bergmannsheil University Hospitals, Ruhr University of Bochum, 44789, Bochum, Germany
| | - Assem Aweimer
- Institute of Physiology, Department of Cellular and Translational Physiology, Medical Faculty and Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany
| | - Nazha Hamdani
- Institute of Physiology, Department of Cellular and Translational Physiology, Medical Faculty and Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany
- HCEMM-Cardiovascular Research Group, Department of Pharmacology and Pharmacotherapy, University of Budapest, Budapest, Hungary
- Department of Physiology, Cardiovascular Research Institute Maastricht University Maastricht, Maastricht, the Netherlands
| | - Xiaobo Zhou
- Cardiology, Angiology, Haemostaseology, and Medical Intensive Care, Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Heidelberg/Mannheim, Medical Centre Mannheim, Heidelberg University, Germany
- Key Laboratory of Medical Electrophysiology of Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yonghui Zhao
- Heart Center of Henan Provincial People's Hospital, Central China Fuwai Hospital, Central China Fuwai Hospital of Zhengzhou University, Zhengzhou, Henan, 450003, China
| | - Ibrahim Akin
- Cardiology, Angiology, Haemostaseology, and Medical Intensive Care, Medical Centre Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Heidelberg/Mannheim, Medical Centre Mannheim, Heidelberg University, Germany
| | - Ibrahim El-Battrawy
- Department of Cardiology and Angiology, Bergmannsheil University Hospitals, Ruhr University of Bochum, 44789, Bochum, Germany
- Institute of Physiology, Department of Cellular and Translational Physiology, Medical Faculty and Institut für Forschung und Lehre (IFL), Molecular and Experimental Cardiology, Ruhr University Bochum, Bochum, Germany
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3
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Krysov VA, Wilson RH, Ten NS, Youlton N, De Jong HN, Sutton S, Huang Y, Reuter CM, Grove ME, Wheeler MT, Ashley EA, Parikh VN. Regional Variation in Cardiovascular Genes Enables a Tractable Genome Editing Strategy. CIRCULATION. GENOMIC AND PRECISION MEDICINE 2024; 17:e004370. [PMID: 38506054 PMCID: PMC11020015 DOI: 10.1161/circgen.123.004370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 03/10/2024] [Indexed: 03/21/2024]
Abstract
BACKGROUND To realize the potential of genome engineering therapeutics, tractable strategies must be identified that balance personalized therapy with the need for off-the-shelf availability. We hypothesized that regional clustering of pathogenic variants can inform the design of rational prime editing therapeutics to treat the majority of genetic cardiovascular diseases with a limited number of reagents. METHODS We collated 2435 high-confidence pathogenic/likely pathogenic (P/LP) variants in 82 cardiovascular disease genes from ClinVar. We assessed the regional density of these variants by defining a regional clustering index. We then combined a highly active base editor with prime editing to demonstrate the feasibility of a P/LP hotspot-directed genome engineering therapeutic strategy in vitro. RESULTS P/LP variants in cardiovascular disease genes display higher regional density than rare variants found in the general population. P/LP missense variants displayed higher average regional density than P/LP truncating variants. Following hypermutagenesis at a pathogenic hotspot, mean prime editing efficiency across introduced variants was 57±27%. CONCLUSIONS Designing therapeutics that target pathogenic hotspots will not only address known missense P/LP variants but also novel P/LP variants identified in these hotspots as well. Moreover, the clustering of P/LP missense rather than truncating variants in these hotspots suggests that prime editing technology is particularly valuable for dominant negative disease. Although prime editing technology in relation to cardiac health continues to improve, this study presents an approach to targeting the most impactful regions of the genome for inherited cardiovascular disease.
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Affiliation(s)
- Vikki A. Krysov
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
- University of California, Davis School of Medicine, Sacramento, CA (V.A.K.)
| | - Rachel H. Wilson
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
| | - Nicholas S. Ten
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
| | - Nathan Youlton
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
| | - Hannah N. De Jong
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA (H.N.D.J., E.A.A.)
- Maze Therapeutics, Inc., San Francisco, CA (H.N.D.J.)
| | - Shirley Sutton
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
| | - Yong Huang
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
| | - Chloe M. Reuter
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
- Color Health, Burlingame, CA (C.M.R., M.E.G.)
| | | | - Matthew T. Wheeler
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
- Stanford Center for Inherited Cardiovascular Disease, Stanford Medicine, CA (M.T.W., E.A.A., V.N.P.)
| | - Euan A. Ashley
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
- Department of Genetics, Stanford University School of Medicine, Palo Alto, CA (H.N.D.J., E.A.A.)
- Stanford Center for Inherited Cardiovascular Disease, Stanford Medicine, CA (M.T.W., E.A.A., V.N.P.)
| | - Victoria N. Parikh
- Division of Cardiovascular Medicine (V.A.K., R.H.W., N.S.T., N.Y., H.N.D.J., S.S., Y.H., C.M.R., M.T.W., E.A.A., V.N.P.)
- Stanford Center for Inherited Cardiovascular Disease, Stanford Medicine, CA (M.T.W., E.A.A., V.N.P.)
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Li S, Zhang Z, Ding Y, Yu T, Qin Z, Guo S. Dissecting the associations of KCNH2 genetic polymorphisms with various types of cardiac arrhythmias. Gene 2024; 899:148132. [PMID: 38181928 DOI: 10.1016/j.gene.2024.148132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/16/2023] [Accepted: 01/02/2024] [Indexed: 01/07/2024]
Abstract
BACKGROUND Cardiac arrhythmia, a common cardiovascular disease, is closely related to genetic polymorphisms. However, the associations between polymorphisms in KCNH2 and various arrhythmias remain inadequately explored. METHODS Guided by the assumption that KCNH2 genetic polymorphisms significantly contribute to the development of arrhythmias, we thoroughly explored the associations between 85 KCNH2 genetic variations and 16 cardiac arrhythmias in a sample obtained from the UK Biobank (UKBB, N = 307,473). The illnesses documented in the electronic medical records of the sample were mapped to a phecode system for a more accurate representation of distinct phenotypes. Survival analysis was used to test the effect of KCNH2 variants on arrhythmia incidence, and a phenotype-wide association study (PheWAS) was performed to investigate the effect of KCNH2 polymorphisms on 102 traits, including physical measurements, biomarkers, and hematological indicators. RESULTS Novel associations of variants rs2269001 and rs7789585 in KCNH2 with paroxysmal tachycardia (PT) and atrial fibrillation/flutter (AF/AFL), respectively, were identified. Moreover, with an increase in the number of minor alleles of these two variants, the incidence rates of PT and AF/AFL decreased. In addition, the PheWAS results suggested that these two single nucleotide polymorphisms were associated with multiple parameters in physical measurements and neutrophil percentage. CONCLUSION The multiple novel associations observed in this study illustrate the importance of KCNH2 genetic variations in the pathogenesis of arrhythmia.
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Affiliation(s)
- Sen Li
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China.
| | - Zhang Zhang
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China.
| | - Yining Ding
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China.
| | - Tingting Yu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, China.
| | - Zongshi Qin
- Peking University Clinical Research Institute, Peking University, Beijing, China.
| | - Shuzhen Guo
- School of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China.
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5
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Lin M, Li C, Lin C, Xiong S, Xue Q, Li Y. Characterization of amiodarone action on currents in hERG-T618 gain-of-function mutations. Open Life Sci 2023; 18:20220749. [PMID: 37954102 PMCID: PMC10638844 DOI: 10.1515/biol-2022-0749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 11/14/2023] Open
Abstract
The purpose of this study was to determine the effect of amiodarone (Ami) on hERG-T618I currents in HEK293 cells. A transient transfection method was used to transfer hERG-T618I and hERG wild-type (WT) channel plasmids into HEK293 cells. An extracellular local perfusion method was used for administration. Currents were recorded using the whole-cell patch clamp technique. Ami (10 μM) had a greater retarding effect on the hERG-T618I channel than WT (P < 0.05). The half-inhibitory concentration for the mutant was approximately 1.82 times that of WT (P < 0.05). The WT current inhibition fraction against Ami was significantly greater than T618I in the same cell (P < 0.05). The STEP current of the mutant channel was larger than the WT channel, but the characteristic of inward rectification did not appear. Ami reduced the STEP current of the mutant channel, and the steady-state activation curve indicated that channel activation decreased (P > 0.05). Ami restored partial inactivation of the mutant channel. Ami effectively reduced the current in the phase 2 plateau (P < 0.05), but the phase 3 current did not exhibit the characteristics of a WT current. Ami inhibited hERG-T618I currents on HEK293 cells, but the effect was weaker than WT.
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Affiliation(s)
- Min Lin
- Department of Cardiology, People’s Hospital Affiliated to Fujian University of Traditional Chinese Medicine, Fuzhou, 350004, China
| | - Cuiyun Li
- Department of Cardiology, People’s Hospital Affiliated to Fujian University of Traditional Chinese Medicine, Fuzhou, 350004, China
| | - Chao Lin
- Department of Cardiology, People’s Hospital Affiliated to Fujian University of Traditional Chinese Medicine, Fuzhou, 350004, China
| | - Shangquan Xiong
- Department of Cardiology, People’s Hospital Affiliated to Fujian University of Traditional Chinese Medicine, Fuzhou, 350004, China
| | - Qiao Xue
- Department of Cardiology, Chinese PLA General Hospital, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China
| | - Yang Li
- Department of Cardiology, Chinese PLA General Hospital, No. 28 Fuxing Road, Haidian District, Beijing, 100853, China
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Zhang S, Lu W, Yang F, Li Z, Wang S, Jiang M, Wang X, Wei Z. Computational analysis of arrhythmogenesis in KCNH2 T618I mutation-associated short QT syndrome and the pharmacological effects of quinidine and sotalol. NPJ Syst Biol Appl 2022; 8:43. [PMID: 36333337 PMCID: PMC9636227 DOI: 10.1038/s41540-022-00254-5] [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: 06/13/2022] [Accepted: 10/18/2022] [Indexed: 11/06/2022] Open
Abstract
Short QT syndrome (SQTS) is a rare but dangerous genetic disease. In this research, we conducted a comprehensive in silico investigation into the arrhythmogenesis in KCNH2 T618I-associated SQTS using a multi-scale human ventricle model. A Markov chain model of IKr was developed firstly to reproduce the experimental observations. It was then incorporated into cell, tissue, and organ models to explore how the mutation provided substrates for ventricular arrhythmias. Using this T618I Markov model, we explicitly revealed the subcellular level functional alterations by T618I mutation, particularly the changes of ion channel states that are difficult to demonstrate in wet experiments. The following tissue and organ models also successfully reproduced the changed dynamics of reentrant spiral waves and impaired rate adaptions in hearts of T618I mutation. In terms of pharmacotherapy, we replicated the different effects of a drug under various conditions using identical mathematical descriptions for drugs. This study not only simulated the actions of an effective drug (quinidine) at various physiological levels, but also elucidated why the IKr inhibitor sotalol failed in SQT1 patients through profoundly analyzing its mutation-dependent actions.
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Affiliation(s)
- Shugang Zhang
- College of Computer Science and Technology, Ocean University of China, Qingdao, 266100, China
| | - Weigang Lu
- Department of Educational Technology, Ocean University of China, Qingdao, 266100, China.
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK.
| | - Fei Yang
- School of Mechanical, Electrical, and Information Engineering, Shandong University, Weihai, 264200, China
| | - Zhen Li
- College of Computer Science and Technology, Qingdao University, Qingdao, 266071, China
| | - Shuang Wang
- College of Computer Science and Technology, China University of Petroleum (East China), Qingdao, 266580, China
| | - Mingjian Jiang
- School of Information and Control Engineering, Qingdao University of Technology, Qingdao, 266033, China
| | | | - Zhiqiang Wei
- College of Computer Science and Technology, Ocean University of China, Qingdao, 266100, China
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Du C, Zhang H, Harmer SC, Hancox JC. Identification through action potential clamp of proarrhythmic consequences of the short QT syndrome T618I hERG 'hotspot' mutation. Biochem Biophys Res Commun 2022; 596:49-55. [PMID: 35114584 PMCID: PMC8865743 DOI: 10.1016/j.bbrc.2022.01.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 01/14/2022] [Indexed: 11/30/2022]
Abstract
The T618I KCNH2-encoded hERG mutation is the most frequently observed mutation in genotyped cases of the congenital short QT syndrome (SQTS), a cardiac condition associated with ventricular fibrillation and sudden death. Most T618I hERG carriers exhibit a pronounced U wave on the electrocardiogram and appear vulnerable to ventricular, but not atrial fibrillation (AF). The basis for these effects is unclear. This study used the action potential (AP) voltage clamp technique to determine effects of the T618I mutation on hERG current (IhERG) elicited by APs from different cardiac regions. Whole-cell patch-clamp recordings were made at 37 °C of IhERG from hERG-transfected HEK-293 cells. Maximal IhERG during a ventricular AP command was increased ∼4-fold for T618I IhERG and occurred much earlier during AP repolarization. The mutation also increased peak repolarizing currents elicited by Purkinje fibre (PF) APs. Maximal wild-type (WT) IhERG current during the PF waveform was 87.2 ± 4.5% of maximal ventricular repolarizing current whilst for the T618I mutant, the comparable value was 47.7 ± 2.7%. Thus, the T618I mutation exacerbated differences in repolarizing IhERG between PF and ventricular APs; this could contribute to heterogeneity of ventricular-PF repolarization and consequently to the U waves seen in T618I carriers. The comparatively shorter duration and lack of pronounced plateau of the atrial AP led to a smaller effect of the T618I mutation during the atrial AP, which may help account for the lack of reported AF in T618I carriers. Use of a paired ventricular AP protocol revealed an alteration to protective IhERG transients that affect susceptibility to premature excitation late in AP repolarization/early in diastole. These observations may help explain altered arrhythmia susceptibility in this form of the SQTS. T618I is a ‘hotspot’ hERG potassium channel mutation in the congenital short QT syndrome. Differences in hERG current during ventricular and Purkinje fibre action potentials are exacerbated by the T618I mutation. T618I has more modest effects on current during atrial action potentials. T618I modifies the protective response of hERG to premature ventricular excitation. These alterations to hERG function help explain ECG changes reported in T618I-hERG carriers.
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Affiliation(s)
- Chunyun Du
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Henggui Zhang
- Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - Stephen C Harmer
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Jules C Hancox
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK; Biological Physics Group, Department of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK.
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8
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Fan X, Yang G, Kowitz J, Duru F, Saguner AM, Akin I, Zhou X, El-Battrawy I. Preclinical short QT syndrome models: studying the phenotype and drug-screening. Europace 2021; 24:481-493. [PMID: 34516623 DOI: 10.1093/europace/euab214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 09/05/2021] [Indexed: 11/14/2022] Open
Abstract
Cardiovascular diseases are the main cause of sudden cardiac death (SCD) in developed and developing countries. Inherited cardiac channelopathies are linked to 5-10% of SCDs, mainly in the young. Short QT syndrome (SQTS) is a rare inherited channelopathy, which leads to both atrial and ventricular tachyarrhythmias, syncope, and even SCD. International European Society of Cardiology guidelines include as diagnostic criteria: (i) QTc ≤ 340 ms on electrocardiogram, (ii) QTc ≤ 360 ms plus one of the follwing, an affected short QT syndrome pathogenic gene mutation, or family history of SQTS, or aborted cardiac arrest, or family history of cardiac arrest in the young. However, further evaluation of the QTc ranges seems to be required, which might be possible by assembling large short QT cohorts and considering genetic screening of the newly described pathogenic mutations. Since the mechanisms underlying the arrhythmogenesis of SQTS is unclear, optimal therapy for SQTS is still lacking. The disease is rare, unclear genotype-phenotype correlations exist in a bevy of cases and the absence of an international short QT registry limit studies on the pathophysiological mechanisms of arrhythmogenesis and therapy of SQTS. This leads to the necessity of experimental models or platforms for studying SQTS. Here, we focus on reviewing preclinical SQTS models and platforms such as animal models, heterologous expression systems, human-induced pluripotent stem cell-derived cardiomyocyte models and computer models as well as three-dimensional engineered heart tissues. We discuss their usefulness for SQTS studies to examine genotype-phenotype associations, uncover disease mechanisms and test drugs. These models might be helpful for providing novel insights into the exact pathophysiological mechanisms of this channelopathy and may offer opportunities to improve the diagnosis and treatment of patients with SQT syndrome.
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Affiliation(s)
- Xuehui Fan
- University of Mannheim, University of Heidelberg, Germany.,Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Collaborative Innovation Center for Prevention of Cardiovascular Diseases, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Guoqiang Yang
- Department of Acupuncture and Rehabilitation, Hospital (T.CM.) Affiliated to Southwest Medical University, Luzhou, Sichuan, China.,Research Unit of Molecular Imaging Probes, Department of Radiologic Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | | | - Firat Duru
- Department of Cardiology, University Heart Centre, University Hospital Zurich, Zurich, Switzerland.,Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Ardan M Saguner
- Department of Cardiology, University Heart Centre, University Hospital Zurich, Zurich, Switzerland
| | - Ibrahim Akin
- University of Mannheim, University of Heidelberg, Germany.,DZHK (German Center for Cardiovascular Research) Partner Site, Heidelberg-Mannheim, Germany
| | - Xiaobo Zhou
- University of Mannheim, University of Heidelberg, Germany.,Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Collaborative Innovation Center for Prevention of Cardiovascular Diseases, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China.,DZHK (German Center for Cardiovascular Research) Partner Site, Heidelberg-Mannheim, Germany
| | - Ibrahim El-Battrawy
- University of Mannheim, University of Heidelberg, Germany.,Department of Cardiology, University Heart Centre, University Hospital Zurich, Zurich, Switzerland
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Crotti L, Odening KE, Sanguinetti MC. Heritable arrhythmias associated with abnormal function of cardiac potassium channels. Cardiovasc Res 2021; 116:1542-1556. [PMID: 32227190 DOI: 10.1093/cvr/cvaa068] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/24/2020] [Accepted: 03/26/2020] [Indexed: 12/16/2022] Open
Abstract
Cardiomyocytes express a surprisingly large number of potassium channel types. The primary physiological functions of the currents conducted by these channels are to maintain the resting membrane potential and mediate action potential repolarization under basal conditions and in response to changes in the concentrations of intracellular sodium, calcium, and ATP/ADP. Here, we review the diversity and functional roles of cardiac potassium channels under normal conditions and how heritable mutations in the genes encoding these channels can lead to distinct arrhythmias. We briefly review atrial fibrillation and J-wave syndromes. For long and short QT syndromes, we describe their genetic basis, clinical manifestation, risk stratification, traditional and novel therapeutic approaches, as well as insights into disease mechanisms provided by animal and cellular models.
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Affiliation(s)
- Lia Crotti
- Center for Cardiac Arrhythmias of Genetic Origin, Istituto Auxologico Italiano, IRCCS, Milan, Italy.,Laboratory of Cardiovascular Genetics, Istituto Auxologico Italiano, IRCCS, Milan, Italy.,Department of Cardiovascular, Neural and Metabolic Sciences, Istituto Auxologico Italiano, IRCCS, San Luca Hospital, Milan, Italy.,Department of Medicine and Surgery, University of Milano-Bicocca, Milan, Italy
| | - Katja E Odening
- Department of Cardiology and Angiology I, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Institute of Experimental Cardiovascular Medicine, Heart Center University of Freiburg, Medical Faculty, Freiburg, Germany.,Department of Cardiology, Translational Cardiology, Inselspital, Bern University Hospital, and Institute of Physiology, University of Bern, Bern, Switzerland
| | - Michael C Sanguinetti
- Department of Internal Medicine, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, USA
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10
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Abstract
The physiological heart function is controlled by a well-orchestrated interplay of different ion channels conducting Na+, Ca2+ and K+. Cardiac K+ channels are key players of cardiac repolarization counteracting depolarizating Na+ and Ca2+ currents. In contrast to Na+ and Ca2+, K+ is conducted by many different channels that differ in activation/deactivation kinetics as well as in their contribution to different phases of the action potential. Together with modulatory subunits these K+ channel α-subunits provide a wide range of repolarizing currents with specific characteristics. Moreover, due to expression differences, K+ channels strongly influence the time course of the action potentials in different heart regions. On the other hand, the variety of different K+ channels increase the number of possible disease-causing mutations. Up to now, a plethora of gain- as well as loss-of-function mutations in K+ channel forming or modulating proteins are known that cause severe congenital cardiac diseases like the long-QT-syndrome, the short-QT-syndrome, the Brugada syndrome and/or different types of atrial tachyarrhythmias. In this chapter we provide a comprehensive overview of different K+ channels in cardiac physiology and pathophysiology.
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11
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Belletti R, Romero L, Martinez-Mateu L, Cherry EM, Fenton FH, Saiz J. Arrhythmogenic Effects of Genetic Mutations Affecting Potassium Channels in Human Atrial Fibrillation: A Simulation Study. Front Physiol 2021; 12:681943. [PMID: 34135774 PMCID: PMC8201780 DOI: 10.3389/fphys.2021.681943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/05/2021] [Indexed: 11/16/2022] Open
Abstract
Genetic mutations in genes encoding for potassium channel protein structures have been recently associated with episodes of atrial fibrillation in asymptomatic patients. The aim of this study is to investigate the potential arrhythmogenicity of three gain-of-function mutations related to atrial fibrillation-namely, KCNH2 T895M, KCNH2 T436M, and KCNE3-V17M-using modeling and simulation of the electrophysiological activity of the heart. A genetic algorithm was used to tune the parameters' value of the original ionic currents to reproduce the alterations experimentally observed caused by the mutations. The effects on action potentials, ionic currents, and restitution properties were analyzed using versions of the Courtemanche human atrial myocyte model in different tissues: pulmonary vein, right, and left atrium. Atrial susceptibility of the tissues to spiral wave generation was also investigated studying the temporal vulnerability. The presence of the three mutations resulted in an overall more arrhythmogenic substrate. Higher current density, action potential duration shortening, and flattening of the restitution curves were the major effects of the three mutations at the single-cell level. The genetic mutations at the tissue level induced a higher temporal vulnerability to the rotor's initiation and progression, by sustaining spiral waves that perpetuate until the end of the simulation. The mutation with the highest pro-arrhythmic effects, exhibiting the widest sustained VW and the smallest meandering rotor's tip areas, was KCNE3-V17M. Moreover, the increased susceptibility to arrhythmias and rotor's stability was tissue-dependent. Pulmonary vein tissues were more prone to rotor's initiation, while in left atrium tissues rotors were more easily sustained. Re-entries were also progressively more stable in pulmonary vein tissue, followed by the left atrium, and finally the right atrium. The presence of the genetic mutations increased the susceptibility to arrhythmias by promoting the rotor's initiation and maintenance. The study provides useful insights into the mechanisms underlying fibrillatory events caused by KCNH2 T895M, KCNH2 T436M, and KCNE3-V17M and might aid the planning of patient-specific targeted therapies.
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Affiliation(s)
- Rebecca Belletti
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Lucia Romero
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
| | - Laura Martinez-Mateu
- Departamento de Teoría de la Señal y Comunicaciones y Sistemas Telemáticos y Computación, Universidad Rey Juan Carlos, Madrid, Spain
| | - Elizabeth M. Cherry
- School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, GA, United States
| | - Flavio H. Fenton
- School of Physics, Georgia Institute of Technology, Atlanta, GA, United States
| | - Javier Saiz
- Centro de Investigación e Innovación en Bioingeniería, Universitat Politècnica de València, Valencia, Spain
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12
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Targeting of Potassium Channels in Cardiac Arrhythmias. Trends Pharmacol Sci 2021; 42:491-506. [PMID: 33858691 DOI: 10.1016/j.tips.2021.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/14/2021] [Accepted: 03/17/2021] [Indexed: 02/07/2023]
Abstract
Cardiomyocytes are endowed with a complex repertoire of ion channels, responsible for the generation of action potentials (APs), travelling waves of electrical excitation, propagating throughout the heart and leading to cardiac contractions. Cardiac AP waveforms are shaped by a striking diversity of K+ channels. The pivotal role of K+ channels in cardiac health and disease is underscored by the dramatic impact that K+ channel dysfunction has on cardiac arrhythmias. The development of drugs targeted to specific K+ channels is expected to provide an optimized approach to antiarrhythmic therapy. Here, we review the functional roles of cardiac potassium channels under normal and diseased states. We survey current antiarrhythmic drugs (AADs) targeted to voltage-gated and Ca2+-activated K+ channels and highlight future research opportunities.
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13
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Guo F, Sun Y, Wang X, Wang H, Wang J, Gong T, Chen X, Zhang P, Su L, Fu G, Su J, Yang S, Lai R, Jiang C, Liang P. Patient-Specific and Gene-Corrected Induced Pluripotent Stem Cell-Derived Cardiomyocytes Elucidate Single-Cell Phenotype of Short QT Syndrome. Circ Res 2019; 124:66-78. [PMID: 30582453 DOI: 10.1161/circresaha.118.313518] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
RATIONALE Short QT syndrome (SQT) is a rare but arrhythmogenic disorder featured by shortened ventricular repolarization and a propensity toward life-threatening ventricular arrhythmias and sudden cardiac death. OBJECTIVE This study aimed to investigate the single-cell mechanism of SQT using patient-specific and gene-corrected induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). METHODS AND RESULTS One SQT patient carrying missense mutation T618I in potassium voltage-gated channel subfamily H member 2 ( KCNH2) was recruited as well as 2 healthy control subjects in this study. Control and SQT patient-specific iPSCs were generated from skin fibroblasts using nonintegrated Sendai virus. The KCNH2 T618I mutation was corrected by genome editing in SQT iPSC lines to generate isogenic controls. All iPSCs were differentiated into iPSC-CMs using monolayer-based differentiation protocol. SQT iPSC-CMs exhibited abnormal action potential phenotype featured by shortened action potential duration and increased beat-beat interval variability, when compared with control and gene-corrected iPSC-CMs. Furthermore, SQT iPSC-CMs showed KCNH2 gain-of-function with increased rapid delayed rectifying potassium current (IKr) density and enhanced membrane expression. Gene expression profiling of iPSC-CMs exhibited a differential cardiac ion-channel gene expression profile of SQT. Moreover, QTc of SQT patient and action potential durations of SQT iPSC-CMs were both normalized by quinidine, indicating that quinidine is beneficial to KCNH2 T618I of SQT. Importantly, shortened action potential duration phenotype observed in SQT iPSC-CMs was effectively rescued by a short-peptide scorpion toxin BmKKx2 with a mechanism of targeting KCNH2. CONCLUSIONS We demonstrate that patient-specific and gene-corrected iPSC-CMs are able to recapitulate single-cell phenotype of SQT, which is caused by the gain-of-function mutation KCNH2 T618I. These findings will help elucidate the mechanisms underlying SQT and discover therapeutic drugs for treating the disease by using peptide toxins as lead compounds.
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Affiliation(s)
- Fengfeng Guo
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yaxun Sun
- Department of Cardiology (Y.S., C.J.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaochen Wang
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.)
| | - Hao Wang
- Department of Prenatal Diagnosis (Screening) Center, Hangzhou Women's Hospital (Hangzhou Maternity and Child Health Care Hospital), China (H.W.)
| | - Jue Wang
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.)
| | - Tingyu Gong
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xianzhen Chen
- Department of Dermatology and Venerology (X.C.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ping Zhang
- Department of Cardiology, Beijing Tsinghua Changgeng Hospital, China (P.Z.)
| | - Lan Su
- Cardiovascular Medicine Department, The First Affiliated Hospital of Wenzhou Medical University, China (L.S.)
| | - Guosheng Fu
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.)
| | - Jun Su
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.).,Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences (S.Y., L.R.), Kunming Institute of Zoology, China
| | - Shilong Yang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences (S.Y., L.R.), Kunming Institute of Zoology, China.,Key Laboratory of Bioactive Peptides of Yunnan Province (S.Y., L.R.), Kunming Institute of Zoology, China
| | - Ren Lai
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences (S.Y., L.R.), Kunming Institute of Zoology, China.,Key Laboratory of Bioactive Peptides of Yunnan Province (S.Y., L.R.), Kunming Institute of Zoology, China
| | - Chenyang Jiang
- Department of Cardiology (Y.S., C.J.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ping Liang
- From the Key Laboratory of Combined Multi-organ Transplantation, Ministry of Public Health, the First Affiliated Hospital (F.G., X.W., J.W., T.G., J.S., P.L.), Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Institute of Translational Medicine, Zhejiang University, Hangzhou, China (F.G., X.W., J.W., J.S., P.L.)
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14
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Differential expression of genes participating in cardiomyocyte electrophysiological remodeling via membrane ionic mechanisms and Ca 2+-handling in human heart failure. Mol Cell Biochem 2019; 463:33-44. [PMID: 31520233 DOI: 10.1007/s11010-019-03626-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/04/2019] [Indexed: 12/16/2022]
Abstract
Excitation-contraction coupling in normal cardiac function is performed with well balanced and coordinated functioning but with complex dynamic interactions between functionally connected membrane ionic currents. However, their genomic investigations provide essential information on the regulation of diseases by their transcripts. Therefore, we examined the gene expression levels of the most important voltage-gated ionic channels such as Na+-channels (SCN5A), Ca2+-channels (CACNA1C and CACNA1H), and K+-channels, including transient outward (KCND2, KCNA2, KCNA5, KCNA8), inward rectifier (KCNJ2, KCNJ12, KCNJ4), and delayed rectifier (KCNB1) in left ventricular tissues from either ischemic or dilated cardiomyopathy (ICM or DCM). We also examined the mRNA levels of ATP-dependent K+-channels (KCNJ11, ABCC9) and ERG-family channels (KCNH2). We further determined the mRNA levels of ryanodine receptors (RyR2; ARVC2), phospholamban (PLB or PLN), SR Ca2+-pump (SERCA2; ATP2A1), an accessory protein FKBP12 (PPIASE), protein kinase A (PPNAD4), and Ca2+/calmodulin-dependent protein kinase II (CAMK2G). The mRNA levels of SCN5A, CACNA1C, and CACNA1H in both groups decreased markedly in the heart samples with similar significance, while KvLQT1 genes were high with depressed Kv4.2. The KCNJ11 and KCNJ12 in both groups were depressed, while the KCNJ4 level was significantly high. More importantly, the KCNA5 gene was downregulated only in the ICM, while the KCNJ2 was upregulated only in the DCM. Besides, mRNA levels of ARVC2 and PLB were significantly high compared to the controls, whereas others (ATP2A1, PPIASE, PPNAD4, and CAMK2G) were decreased. Importantly, the increases of KCNB1 and KCNJ11 were more prominent in the ICM than DCM, while the decreases in ATP2A1 and FKBP1A were more prominent in DCM compared to ICM. Overall, this study was the first to demonstrate that the different levels of changes in gene profiles via different types of cardiomyopathy are prominent particularly in some K+-channels, which provide further information about our knowledge of how remodeling processes can be differentiated in HF originated from different pathological conditions.
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15
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Rico-Mesa JS, Al Qaysi M, Sovic W, Endo-Carvajal M, Badin A. Rare but lethal short QT syndrome: most recent understanding of the disease. ELECTRONIC JOURNAL OF GENERAL MEDICINE 2019. [DOI: 10.29333/ejgm/108495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Campuzano O, Fernandez-Falgueras A, Lemus X, Sarquella-Brugada G, Cesar S, Coll M, Mates J, Arbelo E, Jordà P, Perez-Serra A, Del Olmo B, Ferrer-Costa C, Iglesias A, Fiol V, Puigmulé M, Lopez L, Pico F, Brugada J, Brugada R. Short QT Syndrome: A Comprehensive Genetic Interpretation and Clinical Translation of Rare Variants. J Clin Med 2019; 8:jcm8071035. [PMID: 31315195 PMCID: PMC6678338 DOI: 10.3390/jcm8071035] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 07/08/2019] [Accepted: 07/11/2019] [Indexed: 12/14/2022] Open
Abstract
Short QT syndrome, one of the most lethal entities associated with sudden cardiac death, is a rare genetic disease characterized by short QT intervals detected by electrocardiogram. Several genetic variants are causally linked to the disease, but there has yet to be a comprehensive analysis of variants among patients with short QT syndrome. To fill this gap, we performed an exhaustive study of variants currently catalogued as deleterious in short QT syndrome according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Analysis of the 32 variants described in the literature determined that only nine (28.12%) have a conclusive pathogenic role. All definitively pathogenic variants are located in KCNQ1, KCNH2, or KCNJ2; three genes encoding potassium channels. Other variants located in genes encoding calcium or sodium channels are associated with electrical alterations concomitant with shortened QT intervals but do not guarantee a diagnosis of short QT syndrome. We recommend caution regarding previously reported variants classified as pathogenic. An exhaustive re-analysis is necessary to clarify the role of each variant before routinely translating genetic findings to the clinical setting.
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Affiliation(s)
- Oscar Campuzano
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain.
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain.
- Medical Science Department, School of Medicine, University of Girona, 17071 Girona, Spain.
- Biochemistry and Molecular Genetics Department, Hospital Clinic, IDIBAPS, 08036 Barcelona, Spain.
| | | | - Ximena Lemus
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Georgia Sarquella-Brugada
- Medical Science Department, School of Medicine, University of Girona, 17071 Girona, Spain
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain
| | - Sergi Cesar
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain
| | - Monica Coll
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Jesus Mates
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Elena Arbelo
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Arrhythmias Unit, Hospital Clinic, University of Barcelona, 08036 Barcelona, Spain
| | - Paloma Jordà
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Arrhythmias Unit, Hospital Clinic, University of Barcelona, 08036 Barcelona, Spain
| | | | - Bernat Del Olmo
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Carles Ferrer-Costa
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Anna Iglesias
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Victoria Fiol
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain
| | - Marta Puigmulé
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Laura Lopez
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Ferran Pico
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Josep Brugada
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08950 Barcelona, Spain
- Arrhythmias Unit, Hospital Clinic, University of Barcelona, 08036 Barcelona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain.
- Centro Investigación Biomédica en Red Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain.
- Medical Science Department, School of Medicine, University of Girona, 17071 Girona, Spain.
- Cardiology Service, Hospital Josep Trueta, University of Girona, 17007 Girona, Spain.
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17
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Butler A, Zhang Y, Stuart AG, Dempsey CE, Hancox JC. Functional and pharmacological characterization of an S5 domain hERG mutation associated with short QT syndrome. Heliyon 2019; 5:e01429. [PMID: 31049424 PMCID: PMC6479114 DOI: 10.1016/j.heliyon.2019.e01429] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/21/2019] [Accepted: 03/22/2019] [Indexed: 11/18/2022] Open
Abstract
Congenital short QT syndrome (SQTS) is a repolarization disorder characterized by abbreviated QT intervals, atrial and ventricular arrhythmias and a risk of sudden death. This study characterized a missense mutation (I560T) in the S5 domain of the hERG K+ channel that has been associated with variant 1 of the SQTS. Whole cell patch clamp recordings of wild-type (WT) and I560T hERG current (IhERG) were made at 37 °C from hERG expressing HEK 293 cells, and the structural context of the mutation was investigated using a recently reported cryo-EM structure of hERG. Under conventional voltage clamp, the I560T mutation increased IhERG amplitude without altering the voltage-dependence of activation, although it accelerated activation time-course and also slowed deactivation time-course at some voltages. The voltage dependence of IhERG inactivation was positively shifted (by ∼24 mV) and the time-course of inactivation was slowed by the I560T mutation. There was also a modest decrease in K+ over Na+ ion selectivity with the I560T mutation. Under action potential (AP) voltage clamp, the net charge carried by hERG was significantly increased during ventricular, Purkinje fibre and atrial APs, with maximal IhERG also occurring earlier during the plateau phase of ventricular and Purkinje fibre APs. The I560T mutation exerted only a modest effect on quinidine sensitivity of IhERG: the IC50 for mutant IhERG was 2.3 fold that for WT IhERG under conventional voltage clamp. Under AP voltage clamp the inhibitory effect of 1 μM quinidine was largely retained for I560T hERG and the timing of peak I560T IhERG was altered towards that of the WT channel. In both the open channel structure and a closed hERG channel model based on the closely-related EAG structure, I560T side-chains were oriented towards membrane lipid and away from adjacent domains of the channel, contrasting with previous predictions based on homology modelling. In summary, the I560T mutation produces multiple effects on hERG channel operation that result in a gain-of-function that is expected to abbreviate ventricular, atrial and Purkinje fibre repolarization. Quinidine is likely to be of value in offsetting the increase in IhERG and altered IhERG timing during ventricular APs in SQTS with this mutation.
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Affiliation(s)
- Andrew Butler
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
| | - Yihong Zhang
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
- Corresponding author.
| | - A. Graham Stuart
- Bristol Heart Institute, University of Bristol, Bristol, BS2 8HW, United Kingdom
| | - Christopher E. Dempsey
- School of Biochemistry, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, BS8 1TD, United Kingdom
- Bristol Heart Institute, University of Bristol, Bristol, BS2 8HW, United Kingdom
- Corresponding author.
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18
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Hancox JC, Whittaker DG, Zhang H, Stuart AG. Learning from studying very rare cardiac conditions: the example of short QT syndrome. JOURNAL OF CONGENITAL CARDIOLOGY 2019. [DOI: 10.1186/s40949-019-0024-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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19
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20
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Hancox JC, Whittaker DG, Du C, Stuart AG, Zhang H. Emerging therapeutic targets in the short QT syndrome. Expert Opin Ther Targets 2018; 22:439-451. [DOI: 10.1080/14728222.2018.1470621] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jules C Hancox
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, United Kingdom
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Dominic G Whittaker
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Chunyun Du
- School of Physiology, Pharmacology and Neuroscience, Medical Sciences Building, University Walk, Bristol, United Kingdom
| | - A. Graham Stuart
- Cardiology, Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
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21
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Ion Channel Disorders and Sudden Cardiac Death. Int J Mol Sci 2018; 19:ijms19030692. [PMID: 29495624 PMCID: PMC5877553 DOI: 10.3390/ijms19030692] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 12/19/2022] Open
Abstract
Long QT syndrome, short QT syndrome, Brugada syndrome and catecholaminergic polymorphic ventricular tachycardia are inherited primary electrical disorders that predispose to sudden cardiac death in the absence of structural heart disease. Also known as cardiac channelopathies, primary electrical disorders respond to mutations in genes encoding cardiac ion channels and/or their regulatory proteins, which result in modifications in the cardiac action potential or in the intracellular calcium handling that lead to electrical instability and life-threatening ventricular arrhythmias. These disorders may have low penetrance and expressivity, making clinical diagnosis often challenging. However, because sudden cardiac death might be the first presenting symptom of the disease, early diagnosis becomes essential. Genetic testing might be helpful in this regard, providing a definite diagnosis in some patients. Yet important limitations still exist, with a significant proportion of patients remaining with no causative mutation identifiable after genetic testing. This review aims to provide the latest knowledge on the genetic basis of cardiac channelopathies and discuss the role of the affected proteins in the pathophysiology of each one of these diseases.
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22
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Sun YX, Gao J, Jiang CY, Xue YM, Xu YZ, Liu G, Guo JH, Sheng X, Ye Y, He H, Zhao YT, Barajas-Martinez H, Fu GS, Hu D. T Wave Safety Margin during the Process of ICD Implantation As a Novel Predictor of T Wave Oversensing. Front Physiol 2017; 8:659. [PMID: 28919866 PMCID: PMC5585188 DOI: 10.3389/fphys.2017.00659] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 08/18/2017] [Indexed: 11/13/2022] Open
Abstract
Introduction: T wave oversensing (TWOS) is a major drawback of implantable cardioverter defibrillator (ICD) and data on predictors of TWOS in ICD is limited. We aimed to calculate a novel index of T wave safety margin (TWSM) and assess its potential for evaluating TWOS during the procedure of ICD implantation. Methods and Results: Thirty-two consecutive patients with ICD implantation were enrolled. During each procedure of ICD implantation, different ICD generators were connected to implanted sensing lead through active-fixation leads and bridging cables. R and T wave amplitudes were measured on ICD printouts according to the gain. The ICDs were programed to the most sensitive settings to reveal possible TWOS. A novel index TWSM was calculated according to the corresponding sensing algorithm of ICD. There was discrepancy of R wave amplitudes measured by different ICDs (P < 0.01). In Fortify and Teligen ICDs, T wave amplitudes showed no difference (P > 0.05) and TWSMs were sufficiently high (post sensing: 13.0 ± 7.6 and 28.3 ± 16.5, respectively, post pacing: 5.0 ± 2.2 and 4.6 ± 0.9, respectively). In nine patients with 10 TWOS episodes detected during the procedure of ICD implantation, generators with the highest TWSM were chosen. Only one TWOS episode during pacing was recorded during the 25 ± 7 mo follow-up period. Conclusions: We first propose the index of TWSM during ICD implantation as a potentially efficient predictor for TWOS. Evaluation of TWSM might help to reduce TWOS episodes in patients with high risk of TWOS. Prospective studies are warranted to validate this index and its potential to reduce TWOS episodes.
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Affiliation(s)
- Ya-Xun Sun
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhou, China
| | - Jing Gao
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhou, China
| | - Chen-Yang Jiang
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhou, China
| | - Yu-Mei Xue
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General HospitalGuangzhou, China
| | - Yi-Zhou Xu
- Department of Cardiology, Hangzhou First People's HospitalHangzhou, China
| | - Gang Liu
- Department of Cardiology, First Hospital of Hebei Medical UniversityShijiazhuang, China
| | - Ji-Hong Guo
- Division of Cardiology, Peking University People's HospitalBeijing, China
| | - Xia Sheng
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhou, China
| | - Yang Ye
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhou, China
| | - Hong He
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhou, China
| | - Yun-Tao Zhao
- Department of Cardiology, Aerospace Center HospitalBeijing, China
| | | | - Guo-Sheng Fu
- Department of Cardiology, Sir Run Run Shaw Hospital, Zhejiang University School of MedicineHangzhou, China
| | - Dan Hu
- Masonic Medical Research LaboratoryUtica, NY, United States.,Department of Cardiology and Cardiovascular Research Institute, Renmin Hospital of Wuhan UniversityWuhan, China
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23
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Hu D, Li Y, Zhang J, Pfeiffer R, Gollob MH, Healey J, Harrell DT, Makita N, Abe H, Sun Y, Guo J, Zhang L, Yan G, Mah D, Walsh EP, Leopold HB, Giustetto C, Gaita F, Zienciuk-Krajka A, Mazzanti A, Priori SG, Antzelevitch C, Barajas-Martinez H. The Phenotypic Spectrum of a Mutation Hotspot Responsible for the Short QT Syndrome. JACC Clin Electrophysiol 2017; 3:727-743. [DOI: 10.1016/j.jacep.2016.11.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 11/18/2016] [Accepted: 11/22/2016] [Indexed: 10/20/2022]
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24
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Mazzanti A, Underwood K, Nevelev D, Kofman S, Priori SG. The new kids on the block of arrhythmogenic disorders: Short QT syndrome and early repolarization. J Cardiovasc Electrophysiol 2017; 28:1226-1236. [PMID: 28569435 DOI: 10.1111/jce.13265] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 05/10/2017] [Accepted: 05/25/2017] [Indexed: 12/20/2022]
Abstract
Short QT syndrome (SQTS) is one of the rarest inheritable cardiac channelopathies, characterized by an accelerated cardiac repolarization, which is also the substrate for the development of life-threatening ventricular arrhythmias. Up to this date, fewer than 200 SQTS cases have been reported in the literature worldwide. Patients with SQTS may experience a cardiac arrest as early as in the neonatal period or as late as 80 years old. The cumulative probability of experiencing a cardiac arrest by the fifth decade of life approaches 40%, highlighting the importance of early recognition and management. SQTS is an autosomal dominant disease with five identified causative genes, including three that encode for potassium channels (KCNH2, KCNQ1, and KCNJ2) and two that encode for subunits of the L-type calcium channels (CACNA1C and CACNB2). The term "early repolarization" (ER) has long been used to refer to a heterogeneous group of specific QRS-T junction patterns that are commonly found on the electrocardiograms of young healthy subjects. In the last decade, it has been suggested that in some individuals, the presence of ER may be associated with an increased risk of sudden cardiac death, and thus the term "early repolarization syndrome" (ERS) has progressively entered into use. Up to this point, however, whether ER constitutes a true primary arrhythmic disorder or whether it is simply a predisposing substrate that facilitates arrhythmias in the presence of other triggers remains an unresolved issue. In this review paper, we aim to integrate the current literature on SQTS and ERS. For each, we will describe the key steps that first led to the identification of the syndrome before moving into a discussion of our current understanding of each entity, including the epidemiology, genetics, diagnosis, clinical manifestations, and management.
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Affiliation(s)
| | | | | | - Shanna Kofman
- Molecular Cardiology, IRCCS ICS Maugeri, Pavia, Italy
| | - Silvia G Priori
- Molecular Cardiology, IRCCS ICS Maugeri, Pavia, Italy.,Department of Molecular Medicine, University of Pavia, Pavia, Italy.,Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
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25
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Interaction among hERG channel blockers is a potential mechanism of death in caffeine overdose. Eur J Pharmacol 2017; 800:23-33. [PMID: 28216052 DOI: 10.1016/j.ejphar.2017.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 02/09/2017] [Accepted: 02/10/2017] [Indexed: 11/22/2022]
Abstract
Caffeine overdose death is due to cardiac arrest, but its mechanism has not been explored in detail. In this study, our data showed that caffeine significantly prolonged the heart rate-corrected QT interval (QTc) of rabbits in vivo (P<0.05; n=7). Caffeine was also found to be a hERG channel blocker with an IC50 of 5.04mM (n=5). Although these two findings likely link caffeine overdose death with hERG channel blockade, the amount of caffeine consumption needed to reach the IC50 is very high. Further study demonstrated that addition another hERG blocker could lower the consumption of caffeine significantly, no matter whether two hERG blockers share the same binding sites. Our data does not rule out other possibility, however, it suggests that there is a potential causal relationship between caffeine overdose death with hERG channel and the interaction among these hERG blockers.
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26
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Omar A, Zhou M, Berman A, Sorrentino RA, Yar N, Weintraub NL, Kim IM, Lei W, Tang Y. Genomic-based diagnosis of arrhythmia disease in a personalized medicine era. EXPERT REVIEW OF PRECISION MEDICINE AND DRUG DEVELOPMENT 2016; 1:497-504. [PMID: 28944294 PMCID: PMC5606339 DOI: 10.1080/23808993.2016.1264258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Although thousands of potentially disease-causing mutations have been identified in a handful of genes, the genetic heterogeneity has led to diagnostic confusions, stemming directly from the limitations in our arsenal of genetic tools. AREAS COVERED We discuss the genetic basis of cardiac ion channelopathies, the gaps in our knowledge and how Next-generation sequencing technology (NGS) and can be used to bridge them, and how induced pluripotent stem cell (iPSC) derived-cardiomyocytes can be used for drug discovery. EXPERT COMMENTARY Univariate, arrhythmogenic arrhythmias can explain some congenital arrhythmias, however, it is far from a comprehensive understanding of the complexity of many arrhythmias. Mutational screening is a critical step in personalized medicine and is critical to the management of patients with arrhythmias. The success of personalized medicine requires a more efficient way to identify a high number of genetic variants potentially implicated in cardiac arrhythmogenic diseases than traditional sequencing methods (eg, Sanger sequencing). Next-generation sequencing technology provides us with unprecedented opportunities to achieve high-throughput, rapid, and cost-effective detection of congenital arrhythmias in patients. Moreover, in personalized medicine era, IPSC derived-cardiomyocytes can be used as 'cardiac arrhythmia in a dish' model for drug discovery, and help us improve management of arrhythmias in patients by developing patient-specific drug therapies with target specificity.
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Affiliation(s)
- Abdullah Omar
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Mi Zhou
- Cardiac Surgery department, Ruijin Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Adam Berman
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Robert A. Sorrentino
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Neela Yar
- Purdue University, West Lafayette, IN, USA
| | - Neal L. Weintraub
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Il-man Kim
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Wei Lei
- Cardiovascular Medicine Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Yaoliang Tang
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
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27
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Liu G, Liu T, Cohen D, Liu T, Yan GX. How to determine cardiac ion channels targeted by drugs using the isolated rabbit ventricular wedge model. J Pharmacol Toxicol Methods 2016; 81:161-70. [PMID: 27195944 DOI: 10.1016/j.vascn.2016.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 05/05/2016] [Accepted: 05/15/2016] [Indexed: 12/01/2022]
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Abstract
Cardiac delayed rectifier potassium channels conduct outward potassium currents during the plateau phase of action potentials and play pivotal roles in cardiac repolarization. These include IKs, IKr and the atrial specific IKur channels. In this article, we will review their molecular identities and biophysical properties. Mutations in the genes encoding delayed rectifiers lead to loss- or gain-of-function phenotypes, disrupt normal cardiac repolarization and result in various cardiac rhythm disorders, including congenital Long QT Syndrome, Short QT Syndrome and familial atrial fibrillation. We will also discuss the prospect of using delayed rectifier channels as therapeutic targets to manage cardiac arrhythmia.
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Affiliation(s)
- Lei Chen
- Department of Pharmacology, College of Physicians & Surgeons of Columbia University, 630 West 168th Street, New York, NY 10032, USA
| | - Kevin J Sampson
- Department of Pharmacology, College of Physicians & Surgeons of Columbia University, 630 West 168th Street, New York, NY 10032, USA
| | - Robert S Kass
- Department of Pharmacology, College of Physicians & Surgeons of Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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POULSEN KRISTIANL, HOTAIT MOSTAFA, CALLOE KIRSTINE, KLAERKE DANA, REBEIZ ABDALLAH, NEMER GEORGES, TEJADA MARIAA, REFAAT MARWANM. The Mutation P.T613a in the Pore Helix of the Kv11.1 Potassium Channel is Associated with Long QT Syndrome. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2015; 38:1304-9. [DOI: 10.1111/pace.12693] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/15/2015] [Accepted: 06/28/2015] [Indexed: 11/30/2022]
Affiliation(s)
- KRISTIAN L. POULSEN
- Department of Veterinary Clinical and Animal Science; University of Copenhagen; Frederiksberg C Denmark
| | - MOSTAFA HOTAIT
- Cardiology Division, Department of Internal Medicine; American University of Beirut; Beirut Lebanon
| | - KIRSTINE CALLOE
- Department of Veterinary Clinical and Animal Science; University of Copenhagen; Frederiksberg C Denmark
| | - DAN A. KLAERKE
- Department of Veterinary Clinical and Animal Science; University of Copenhagen; Frederiksberg C Denmark
| | - ABDALLAH REBEIZ
- Cardiology Division, Department of Internal Medicine; American University of Beirut; Beirut Lebanon
| | - GEORGES NEMER
- Department of Biochemistry and Molecular Genetics; American University of Beirut; Beirut Lebanon
| | - MARIA A. TEJADA
- Department of Veterinary Clinical and Animal Science; University of Copenhagen; Frederiksberg C Denmark
| | - MARWAN M. REFAAT
- Cardiology Division, Department of Internal Medicine; American University of Beirut; Beirut Lebanon
- Department of Biochemistry and Molecular Genetics; American University of Beirut; Beirut Lebanon
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30
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Giustetto C, Scrocco C, Giachino D, Rapezzi C, Mognetti B, Gaita F. The lack of effect of sotalol in short QT syndrome patients carrying the T618I mutation in the KCNH2 gene. HeartRhythm Case Rep 2015; 1:373-378. [PMID: 28491588 PMCID: PMC5419677 DOI: 10.1016/j.hrcr.2015.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Carla Giustetto
- Division of Cardiology, University of Torino, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Torino, Italy
- Address reprint requests and correspondence: Dr Carla Giustetto, Division of Cardiology, University of Torino, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Corso Bramante 88, 10126 Torino, Italy.
| | - Chiara Scrocco
- Division of Cardiology, University of Torino, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Torino, Italy
| | - Daniela Giachino
- Medical Genetics, University of Torino, Department of Clinical and Biological Sciences, Torino, Italy
- Medical Genetics San Luigi University Hospital, Orbassano, Italy
| | - Claudio Rapezzi
- Institute of Cardiology, University of Bologna, and S. Orsola-Malpighi Hospital, Bologna, Italy
| | - Barbara Mognetti
- Pharmacology Unit, University of Torino, Department of Clinical and Biological Sciences, Torino, Italy
| | - Fiorenzo Gaita
- Division of Cardiology, University of Torino, Department of Medical Sciences, Città della Salute e della Scienza Hospital, Torino, Italy
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31
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Harrell DT, Ashihara T, Ishikawa T, Tominaga I, Mazzanti A, Takahashi K, Oginosawa Y, Abe H, Maemura K, Sumitomo N, Uno K, Takano M, Priori SG, Makita N. Genotype-dependent differences in age of manifestation and arrhythmia complications in short QT syndrome. Int J Cardiol 2015; 190:393-402. [DOI: 10.1016/j.ijcard.2015.04.090] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 04/03/2015] [Accepted: 04/14/2015] [Indexed: 11/16/2022]
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32
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Giustetto C, Scrocco C, Schimpf R, Maury P, Mazzanti A, Levetto M, Anttonen O, Dalmasso P, Cerrato N, Gribaudo E, Wolpert C, Giachino D, Antzelevitch C, Borggrefe M, Gaita F. Usefulness of exercise test in the diagnosis of short QT syndrome. Europace 2015; 17:628-34. [DOI: 10.1093/europace/euu351] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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33
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Huang CLH. Computational analysis of the electromechanical consequences of short QT syndrome. Front Physiol 2015; 6:44. [PMID: 25717305 PMCID: PMC4324072 DOI: 10.3389/fphys.2015.00044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2014] [Accepted: 01/29/2015] [Indexed: 11/13/2022] Open
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34
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Melgari D, Du C, El Harchi A, Zhang Y, Hancox JC. Suppression of the hERG potassium channel response to premature stimulation by reduction in extracellular potassium concentration. Physiol Rep 2014; 2:2/10/e12165. [PMID: 25318749 PMCID: PMC4254092 DOI: 10.14814/phy2.12165] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Potassium channels encoded by human ether‐à‐go‐go‐related gene (hERG) mediate the cardiac rapid delayed rectifier K+ current (IKr), which participates in ventricular repolarization and has a protective role against unwanted premature stimuli late in repolarization and early in diastole. Ionic current carried by hERG channels (IhERG) is known to exhibit a paradoxical dependence on external potassium concentration ([K+]e), but effects of acute [K+]e changes on the response of IhERG to premature stimulation have not been characterized. Whole‐cell patch‐clamp measurements of hERG current were made at 37°C from hERG channels expressed in HEK293 cells. Under conventional voltage‐clamp, both wild‐type (WT) and S624A pore‐mutant IhERG during depolarization to +20 mV and subsequent repolarization to −40 mV were decreased when superfusate [K+]e was decreased from 4 to 1 mmol/L. When [K+]e was increased from 4 to 10 mmol/L, pulse current was increased and tail IhERG was decreased. Increasing [K+]e produced a +10 mV shift in voltage‐dependent inactivation of WT IhERG and slowed inactivation time course, while lowering [K+]e from 4 to 1 mmol/L produced little change in inactivation voltage dependence, but accelerated inactivation time course. Under action potential (AP) voltage‐clamp, lowering [K+]e reduced the amplitude of IhERG during the AP and suppressed the maximal IhERG response to premature stimuli. Raising [K+]e increased IhERG early during the AP and augmented the IhERG response to premature stimuli. Our results are suggestive that during hypokalemia not only is the contribution of IKr to ventricular repolarization reduced but its ability to protect against unwanted premature stimuli also becomes impaired. hERG potassium channels are important for ventricular repolarization and for protecting the ventricles of the heart from unwanted premature stimuli. This study shows that, in addition to reducing the contribution of hERG channel current to ventricular repolarization, hypokalemia impairs the protective response of hERG to premature stimulation.
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Affiliation(s)
- Dario Melgari
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, University of Bristol, Medical Sciences Building, Bristol, BS8 1TD, UK
| | - Chunyun Du
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, University of Bristol, Medical Sciences Building, Bristol, BS8 1TD, UK
| | - Aziza El Harchi
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, University of Bristol, Medical Sciences Building, Bristol, BS8 1TD, UK
| | - Yihong Zhang
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, University of Bristol, Medical Sciences Building, Bristol, BS8 1TD, UK
| | - Jules C Hancox
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, University of Bristol, Medical Sciences Building, Bristol, BS8 1TD, UK
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35
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Mitcheson J, Arcangeli A. The Therapeutic Potential of hERG1 K+ Channels for Treating Cancer and Cardiac Arrhythmias. ION CHANNEL DRUG DISCOVERY 2014. [DOI: 10.1039/9781849735087-00258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
hERG potassium channels present pharmacologists and medicinal chemists with a dilemma. On the one hand hERG is a major reason for drugs being withdrawn from the market because of drug induced long QT syndrome and the associated risk of inducing sudden cardiac death, and yet hERG blockers are still widely used in the clinic to treat cardiac arrhythmias. Moreover, in the last decade overwhelming evidence has been provided that hERG channels are aberrantly expressed in cancer cells and that they contribute to tumour cell proliferation, resistance to apoptosis, and neoangiogenesis. Here we provide an overview of the properties of hERG channels and their role in excitable cells of the heart and nervous system as well as in cancer. We consider the therapeutic potential of hERG, not only with regard to the negative impact due to drug induced long QT syndrome, but also its future potential as a treatment in the fight against cancer.
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Affiliation(s)
- John Mitcheson
- University of Leicester, Department of Cell Physiology and Pharmacology, Medical Sciences Building University Road Leicester LE1 9HN UK
| | - Annarosa Arcangeli
- Department of Experimental Pathology and Oncology, University of Florence Viale GB Morgagni, 50 50134 Firenze Italy
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36
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Perry MD, Wong S, Ng CA, Vandenberg JI. Hydrophobic interactions between the voltage sensor and pore mediate inactivation in Kv11.1 channels. ACTA ACUST UNITED AC 2014; 142:275-88. [PMID: 23980196 PMCID: PMC3753607 DOI: 10.1085/jgp.201310975] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Kv11.1 channels are critical for the maintenance of a normal heart rhythm. The flow of potassium ions through these channels is controlled by two voltage-regulated gates, termed "activation" and "inactivation," located at opposite ends of the pore. Crucially in Kv11.1 channels, inactivation gating occurs much more rapidly, and over a distinct range of voltages, compared with activation gating. Although it is clear that the fourth transmembrane segments (S4), within each subunit of the tetrameric channel, are important for controlling the opening and closing of the activation gate, their role during inactivation gating is much less clear. Here, we use rate equilibrium free energy relationship (REFER) analysis to probe the contribution of the S4 "voltage-sensor" helix during inactivation of Kv11.1 channels. Contrary to the important role that charged residues play during activation gating, it is the hydrophobic residues (Leu529, Leu530, Leu532, and Val535) that are the key molecular determinants of inactivation gating. Within the context of an interconnected multi-domain model of Kv11.1 inactivation gating, our REFER analysis indicates that the S4 helix and the S4-S5 linker undergo a conformational rearrangement shortly after that of the S5 helix and S5P linker, but before the S6 helix. Combining REFER analysis with double mutant cycle analysis, we provide evidence for a hydrophobic interaction between residues on the S4 and S5 helices. Based on a Kv11.1 channel homology model, we propose that this hydrophobic interaction forms the basis of an intersubunit coupling between the voltage sensor and pore domain that is an important mediator of inactivation gating.
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Affiliation(s)
- Matthew D Perry
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
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37
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Du C, El Harchi A, Zhang H, Hancox JC. Modification by KCNE1 variants of the hERG potassium channel response to premature stimulation and to pharmacological inhibition. Physiol Rep 2013; 1:e00175. [PMID: 24400172 PMCID: PMC3871485 DOI: 10.1002/phy2.175] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 11/02/2013] [Accepted: 11/04/2013] [Indexed: 01/08/2023] Open
Abstract
human Ether-à-go-go-Related Gene (hERG) encodes the pore-forming subunit of cardiac rapid delayed rectifier K(+) current (I Kr) channels, which play important roles in ventricular repolarization, in protecting the myocardium from unwanted premature stimuli, and in drug-induced Long QT Syndrome (LQTS). KCNE1, a small transmembrane protein, can coassemble with hERG. However, it is not known how KCNE1 variants influence the channel's response to premature stimuli or if they influence the sensitivity of hERG to pharmacological inhibition. Accordingly, whole-cell patch-clamp measurements of hERG current (I hERG) were made at 37°C from hERG channels coexpressed with either wild-type (WT) KCNE1 or with one of three KCNE1 variants (A8V, D76N, and D85N). Under both conventional voltage clamp and ventricular action potential (AP) clamp, the amplitude of I hERG was smaller for A8V, D76N, and D85N KCNE1 + hERG than for WT KCNE1 + hERG. Using paired AP commands, with the second AP waveform applied at varying time intervals following the first to mimic premature ventricular excitation, the response of I hERG carried by each KCNE1 variant was reduced compared to that with WT KCNE1 + hERG. The I hERG blocking potency of the antiarrhythmic drug quinidine was similar between WT KCNE1 and the three KCNE1 variants. However, the I hERG inhibitory potency of the antibiotic clarithromycin and of the prokinetic drug cisapride was altered by KCNE1 variants. These results demonstrate that naturally occurring KCNE1 variants can reduce the response of hERG channels to premature excitation and also alter the sensitivity of hERG channels to inhibition by some drugs linked to acquired LQTS.
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Affiliation(s)
- Chunyun Du
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, Medical Sciences Building, University of Bristol Bristol, BS8 1TD, U.K
| | - Aziza El Harchi
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, Medical Sciences Building, University of Bristol Bristol, BS8 1TD, U.K
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, University of Manchester Manchester, M13 9PL, U.K
| | - Jules C Hancox
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, Medical Sciences Building, University of Bristol Bristol, BS8 1TD, U.K
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38
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Sanguinetti MC. HERG1 channel agonists and cardiac arrhythmia. Curr Opin Pharmacol 2013; 15:22-7. [PMID: 24721650 DOI: 10.1016/j.coph.2013.11.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 11/06/2013] [Accepted: 11/07/2013] [Indexed: 01/25/2023]
Abstract
Type 1 human ether-a-go-go-related gene (hERG1) potassium channels are a key determinant of normal repolarization of cardiac action potentials. Loss of function mutations in hERG1 channels cause inherited long QT syndrome and increased risk of cardiac arrhythmia and sudden death. Many common medications that block hERG1 channels as an unintended side effect also increase arrhythmic risk. Routine preclinical screening for hERG1 block led to the discovery of agonists that shorten action potential duration and QT interval. Agonists have the potential to be used as pharmacotherapy for long QT syndrome, but can also be proarrhythmic. Recent studies have elucidated multiple mechanisms of action for these compounds and the structural basis for their binding to the pore domain of the hERG1 channel.
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Affiliation(s)
- Michael C Sanguinetti
- Department of Internal Medicine, Nora Eccles Harrison Cardiovascular Research & Training Institute, University of Utah, 95 South 2000 East, Salt Lake City, UT 84112, USA.
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Abriel H, Rougier JS. β-blockers in congenital short-QT syndrome as ion channel blockers. J Cardiovasc Electrophysiol 2013; 24:1172-4. [PMID: 23890274 DOI: 10.1111/jce.12204] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Hugues Abriel
- Department of Clinical Research, University of Bern, Bern, Switzerland
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Adeniran I, Hancox JC, Zhang H. In silico investigation of the short QT syndrome, using human ventricle models incorporating electromechanical coupling. Front Physiol 2013; 4:166. [PMID: 23847545 PMCID: PMC3701879 DOI: 10.3389/fphys.2013.00166] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 06/14/2013] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION Genetic forms of the Short QT Syndrome (SQTS) arise due to cardiac ion channel mutations leading to accelerated ventricular repolarization, arrhythmias and sudden cardiac death. Results from experimental and simulation studies suggest that changes to refractoriness and tissue vulnerability produce a substrate favorable to re-entry. Potential electromechanical consequences of the SQTS are less well-understood. The aim of this study was to utilize electromechanically coupled human ventricle models to explore electromechanical consequences of the SQTS. METHODS AND RESULTS The Rice et al. mechanical model was coupled to the ten Tusscher et al. ventricular cell model. Previously validated K(+) channel formulations for SQT variants 1 and 3 were incorporated. Functional effects of the SQTS mutations on [Ca(2+)] i transients, sarcomere length shortening and contractile force at the single cell level were evaluated with and without the consideration of stretch-activated channel current (I sac). Without I sac, at a stimulation frequency of 1Hz, the SQTS mutations produced dramatic reductions in the amplitude of [Ca(2+)] i transients, sarcomere length shortening and contractile force. When I sac was incorporated, there was a considerable attenuation of the effects of SQTS-associated action potential shortening on Ca(2+) transients, sarcomere shortening and contractile force. Single cell models were then incorporated into 3D human ventricular tissue models. The timing of maximum deformation was delayed in the SQTS setting compared to control. CONCLUSION The incorporation of I sac appears to be an important consideration in modeling functional effects of SQT 1 and 3 mutations on cardiac electro-mechanical coupling. Whilst there is little evidence of profoundly impaired cardiac contractile function in SQTS patients, our 3D simulations correlate qualitatively with reported evidence for dissociation between ventricular repolarization and the end of mechanical systole.
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Affiliation(s)
- Ismail Adeniran
- Computational Biology, Biological Physics Group, School of Physics and Astronomy, The University of Manchester Manchester, UK
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41
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Gao Y, Xue X, Hu D, Liu W, Yuan Y, Sun H, Li L, Timothy KW, Zhang L, Li C, Yan GX. Inhibition of Late Sodium Current by Mexiletine. Circ Arrhythm Electrophysiol 2013; 6:614-22. [PMID: 23580742 DOI: 10.1161/circep.113.000092] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yuanfeng Gao
- Heart Center, Peking University People's Hospital, Beijing, People's Republic of China
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Perry MD, Ng CA, Vandenberg JI. Pore helices play a dynamic role as integrators of domain motion during Kv11.1 channel inactivation gating. J Biol Chem 2013; 288:11482-91. [PMID: 23471968 DOI: 10.1074/jbc.m113.461442] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteins that form ion-selective pores in the membrane of cells are integral to many rapid signaling processes, including regulating the rhythm of the heartbeat. In potassium channels, the selectivity filter is critical for both endowing an exquisite selectivity for potassium ions, as well as for controlling the flow of ions through the pore. Subtle rearrangements in the complex hydrogen-bond network that link the selectivity filter to the surrounding pore helices differentiate conducting (open) from nonconducting (inactivated) conformations of the channel. Recent studies suggest that beyond the selectivity filter, inactivation involves widespread rearrangements of the channel protein. Here, we use rate equilibrium free energy relationship analysis to probe the structural changes that occur during selectivity filter gating in Kv11.1 channels, at near atomic resolution. We show that the pore helix plays a crucial dynamic role as a bidirectional interface during selectivity filter gating. We also define the molecular bases of the energetic coupling between the pore helix and outer helix of the pore domain that occurs early in the transition from open to inactivated states, as well as the coupling between the pore helix and inner helix late in the transition. Our data demonstrate that the pore helices are more than just static structural elements supporting the integrity of the selectivity filter; instead they play a crucial dynamic role during selectivity filter gating.
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Affiliation(s)
- Matthew D Perry
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
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43
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He FZ, McLeod HL, Zhang W. Current pharmacogenomic studies on hERG potassium channels. Trends Mol Med 2013; 19:227-38. [PMID: 23369369 DOI: 10.1016/j.molmed.2012.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 12/18/2012] [Accepted: 12/27/2012] [Indexed: 11/25/2022]
Abstract
Genetic polymorphisms in human ether-a-go-go-related gene (hERG) potassium channels are associated with many complex diseases and sensitivity to channel-related drugs. Genotypes may underlie different sensitivities to the same drug, and different drugs selectively repair the functional deficits caused by individual mutations. In fact, not all drugs that block hERG function have adverse effects as previously thought. This suggests that the severe adverse reactions observed clinically may only occur in subjects with a particular genotype, but to others may be safe. Similarly, a drug that is ineffective in one population may be both safe and effective in another. Therefore, detecting polymorphisms in KCNH2 encoding hERG1 is of great significance in guiding the prevention and treatment of related diseases, re-evaluating drug safety, and individualizing treatment. This article reviews current pharmacogenomic studies on hERG potassium channels to provide a reference for developing individualized treatments and evaluating their safety.
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Affiliation(s)
- Fa-Zhong He
- Pharmacogenetics Research Institute, Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Changsha, Hunan 410078, PR China
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El Harchi A, Melgari D, Zhang YH, Zhang H, Hancox JC. Action potential clamp and pharmacology of the variant 1 Short QT Syndrome T618I hERG K⁺ channel. PLoS One 2012; 7:e52451. [PMID: 23300672 PMCID: PMC3530446 DOI: 10.1371/journal.pone.0052451] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 11/14/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The familial Short QT Syndrome (SQTS) is associated with an increased risk of cardiac arrhythmia and sudden death. Gain-of-function mutations in the hERG K(+) channel protein have been linked to variant 1 of the SQTS. A hERG channel pore (T618I) mutation has recently been identified in families with heritable SQTS. This study aimed to determine effects of the T618I-hERG mutation on (i) hERG current (I(hERG)) elicited by ventricular action potentials; (ii) the sensitivity of I(hERG) to inhibition by four clinically used antiarrhythmic drugs. METHODS Electrophysiological recordings of I(hERG) were made at 37°C from HEK 293 cells expressing wild-type (WT) or T618I hERG. Whole-cell patch clamp recording was performed using both conventional voltage clamp and ventricular action potential (AP) clamp methods. RESULTS Under conventional voltage-clamp, WT I(hERG) peaked at 0-+10 mV, whilst for T618I I(hERG) maximal current was right-ward shifted to ∼ +40 mV. Voltage-dependent activation and inactivation of T618I I(hERG) were positively shifted (respectively by +15 and ∼ +25 mV) compared to WT I(hERG). The I(hERG) 'window' was increased for T618I compared to WT hERG. Under ventricular AP clamp, maximal repolarising WT I(hERG) occurred at ∼ -30 mV, whilst for T618I hERG peak I(hERG) occurred earlier during AP repolarisation, at ∼ +5 mV. Under conventional voltage clamp, half-maximal inhibitory concentrations (IC(50)) for inhibition of I(hERG) tails by quinidine, disopyramide, D-sotalol and flecainide for T618I hERG ranged between 1.4 and 3.2 fold that for WT hERG. Under action potential voltage clamp, T618I IC(50)s ranged from 1.2 to 2.0 fold the corresponding IC(50) values for WT hERG. CONCLUSIONS The T618I mutation produces a more modest effect on repolarising I(hERG) than reported previously for the N588K-hERG variant 1 SQTS mutation. All drugs studied here appear substantially to retain their ability to inhibit I(hERG) in the setting of the SQTS-linked T618I mutation.
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Affiliation(s)
- Aziza El Harchi
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, University of Bristol, Bristol, United Kingdom
| | - Dario Melgari
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, University of Bristol, Bristol, United Kingdom
| | - Yi Hong Zhang
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Jules C. Hancox
- School of Physiology and Pharmacology and Cardiovascular Research Laboratories, University of Bristol, Bristol, United Kingdom
- * E-mail:
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Wolpert C, Veltmann C, Schimpf R, Borggrefe M, Herrera-Siklody C, Parade U, Strotmann C, Rüb N. [Short QT syndrome]. Herzschrittmacherther Elektrophysiol 2012; 23:220-4. [PMID: 23001291 DOI: 10.1007/s00399-012-0229-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 07/20/2012] [Indexed: 11/24/2022]
Abstract
Short QT syndrome was first described in 2000. It is a sporadic or familial ion channel disease that is associated with abbreviation of the QT interval permanently or transiently. The time of first manifestation of symptoms such as atrial fibrillation or syncope or even sudden death is between the 2nd and 4th decade. Sudden death has also been described for newborns and adolescents. Therapy depends on the severity of the symptoms. The therapy of choice for secondary prevention of sudden death is the implantable cardioverter-defibrillator (ICD). Quinidine has been shown to be effective in preventing arrhythmias in a number of patients. It is mostly used as an adjunct to the ICD but has also been used with considerable success in children and individuals who refused ICD implantation.
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Affiliation(s)
- C Wolpert
- Klinik für Innere Medizin, Kardiologie, Nephrologie und internistische Intensivmedizin, Klinikum Ludwigsburg, Posilipostraße 4, 71640, Ludwigsburg, Germany.
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Vandenberg JI, Perry MD, Perrin MJ, Mann SA, Ke Y, Hill AP. hERG K+ Channels: Structure, Function, and Clinical Significance. Physiol Rev 2012; 92:1393-478. [DOI: 10.1152/physrev.00036.2011] [Citation(s) in RCA: 463] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The human ether-a-go-go related gene (hERG) encodes the pore-forming subunit of the rapid component of the delayed rectifier K+ channel, Kv11.1, which are expressed in the heart, various brain regions, smooth muscle cells, endocrine cells, and a wide range of tumor cell lines. However, it is the role that Kv11.1 channels play in the heart that has been best characterized, for two main reasons. First, it is the gene product involved in chromosome 7-associated long QT syndrome (LQTS), an inherited disorder associated with a markedly increased risk of ventricular arrhythmias and sudden cardiac death. Second, blockade of Kv11.1, by a wide range of prescription medications, causes drug-induced QT prolongation with an increase in risk of sudden cardiac arrest. In the first part of this review, the properties of Kv11.1 channels, including biogenesis, trafficking, gating, and pharmacology are discussed, while the second part focuses on the pathophysiology of Kv11.1 channels.
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Affiliation(s)
- Jamie I. Vandenberg
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Matthew D. Perry
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Mark J. Perrin
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Stefan A. Mann
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Ying Ke
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Adam P. Hill
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
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Chinushi M, Sato A, Izumi D, Furushima H. Nifekalant enlarged the transmural activation-recovery interval difference as well as the peak-to-end interval on surface ECG in a patient with short-QT syndrome. J Cardiovasc Electrophysiol 2012; 23:877-80. [PMID: 22494577 DOI: 10.1111/j.1540-8167.2012.02292.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
A 38-year-old woman with type 1 short-QT syndrome (SQTS) was referred to our hospital. Her ECG showed short QT/QTc interval and peaked T wave. Activation-recovery intervals (ARIs) were calculated from the intracardiac endocardial and epicardial electrode catheters placed in the left ventricle (LV). Intravenous administration of nifekalant prolonged effective refractory period at multiple ventricular sites as well as the QT/QTc interval (from 260/300 to 364/419 ms) on the surface ECG. Nifekalant also enlarged the transmural ARI dispersion of the ventricular repolarization, which was measured by the difference between the longest endocardial ARI and the shortest epicardial ARI during atrial pacing at 90 bpm, from 73 to 103-105 ms. These values corresponded to the intervals between the peak and end of the T wave on the surface ECG. Nifekalant-induced QT interval prolongation on the surface ECG may not indicate attenuation of the arrhythmogenic potential in the heart of SQTS patients.
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Affiliation(s)
- Masaomi Chinushi
- School of Health Science, First Department of Internal Medicine, Niigata University School of Medicine, Niigata, Japan.
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Abstract
The coordinated generation and propagation of action potentials within cardiomyocytes creates the intrinsic electrical stimuli that are responsible for maintaining the electromechanical pump function of the human heart. The synchronous opening and closing of cardiac Na(+), Ca(2+), and K(+) channels corresponds with the activation and inactivation of inward depolarizing (Na(+) and Ca(2+)) and outward repolarizing (K(+)) currents that underlie the various phases of the cardiac action potential (resting, depolarization, plateau, and repolarization). Inherited mutations in pore-forming α subunits and accessory β subunits of cardiac K(+) channels can perturb the atrial and ventricular action potential and cause various cardiac arrhythmia syndromes, including long QT syndrome, short QT syndrome, Brugada syndrome, and familial atrial fibrillation. In this Review, we summarize the current understanding of the molecular and cellular mechanisms that underlie K(+)-channel-mediated arrhythmia syndromes. We also describe translational advances that have led to the emerging role of genetic testing and genotype-specific therapy in the diagnosis and clinical management of individuals who harbor pathogenic mutations in genes that encode α or β subunits of cardiac K(+) channels.
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Giustetto C, Schimpf R, Mazzanti A, Scrocco C, Maury P, Anttonen O, Probst V, Blanc JJ, Sbragia P, Dalmasso P, Borggrefe M, Gaita F. Long-Term Follow-Up of Patients With Short QT Syndrome. J Am Coll Cardiol 2011; 58:587-95. [DOI: 10.1016/j.jacc.2011.03.038] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 02/28/2011] [Accepted: 03/29/2011] [Indexed: 10/17/2022]
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Zhang YH, Colenso CK, Sessions RB, Dempsey CE, Hancox JC. The hERG K(+) channel S4 domain L532P mutation: characterization at 37°C. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2477-87. [PMID: 21777565 PMCID: PMC3245891 DOI: 10.1016/j.bbamem.2011.07.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 06/28/2011] [Accepted: 07/06/2011] [Indexed: 11/10/2022]
Abstract
hERG (human Ether-à-go-go Related Gene) is responsible for ion channels mediating rapid delayed rectifier potassium current, IKr, which is key to cardiac action potential repolarization. Gain-of-function hERG mutations give rise to the SQT1 variant of the Short QT Syndrome (SQTS). Reggae mutant zebrafish, with a S4 zERG mutation (Leucine499Proline; L499P), display arrhythmic features analogous to those seen in the SQTS. The affected S4 domain ERG residue is highly conserved. This study was executed to determine how the homologous hERG mutation (L532P) influences channel function at 37 °C. Whole-cell measurements of current (IhERG) were made from HEK 293 cells expressing WT or L532P hERG. The half maximal activation voltage (V0.5) of L532P IhERG was positively shifted by ~+36 mV compared to WT IhERG; however at negative voltages a pronounced L532P IhERG was observed. Both activation and deactivation time-courses were accelerated for L532P IhERG. The inactivation V0.5 for L532P IhERG was shifted by ~+32 mV. Under action potential (AP) voltage-clamp, L532P IhERG exhibited a dome-shaped current peaking at ~+16 mV, compared to ~−31 mV for WT-IhERG. The L532P mutation produced an ~ 5-fold increase in the IC50 for dronedarone inhibition of IhERG. Homology modeling indicated that the L532 residue within the S4 helix lies closely apposed to the S5 region of an adjacent hERG subunit. Alterations to the S4 domain structure and, potentially, to interactions between adjacent hERG subunits are likely to account for the functional effects of this mutation.
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Affiliation(s)
- Yi H Zhang
- University of Bristol, University Walk, Bristol BS8 1TD, UK
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