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Chan M, Sahakyan H, Eldstrom J, Sastre D, Wang Y, Dou Y, Pourrier M, Vardanyan V, Fedida D. A generic binding pocket for small molecule IKs activators at the extracellular inter-subunit interface of KCNQ1 and KCNE1 channel complexes. eLife 2023; 12:RP87038. [PMID: 37707495 PMCID: PMC10501768 DOI: 10.7554/elife.87038] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023] Open
Abstract
The cardiac IKs ion channel comprises KCNQ1, calmodulin, and KCNE1 in a dodecameric complex which provides a repolarizing current reserve at higher heart rates and protects from arrhythmia syndromes that cause fainting and sudden death. Pharmacological activators of IKs are therefore of interest both scientifically and therapeutically for treatment of IKs loss-of-function disorders. One group of chemical activators are only active in the presence of the accessory KCNE1 subunit and here we investigate this phenomenon using molecular modeling techniques and mutagenesis scanning in mammalian cells. A generalized activator binding pocket is formed extracellularly by KCNE1, the domain-swapped S1 helices of one KCNQ1 subunit and the pore/turret region made up of two other KCNQ1 subunits. A few residues, including K41, A44 and Y46 in KCNE1, W323 in the KCNQ1 pore, and Y148 in the KCNQ1 S1 domain, appear critical for the binding of structurally diverse molecules, but in addition, molecular modeling studies suggest that induced fit by structurally different molecules underlies the generalized nature of the binding pocket. Activation of IKs is enhanced by stabilization of the KCNQ1-S1/KCNE1/pore complex, which ultimately slows deactivation of the current, and promotes outward current summation at higher pulse rates. Our results provide a mechanistic explanation of enhanced IKs currents by these activator compounds and provide a map for future design of more potent therapeutically useful molecules.
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Affiliation(s)
- Magnus Chan
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British ColumbiaVancouverCanada
| | - Harutyun Sahakyan
- Laboratory of Computational Modeling of Biological Processes, Institute of Molecular BiologyYerevanArmenia
| | - Jodene Eldstrom
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British ColumbiaVancouverCanada
| | - Daniel Sastre
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British ColumbiaVancouverCanada
| | - Yundi Wang
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British ColumbiaVancouverCanada
| | - Ying Dou
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British ColumbiaVancouverCanada
| | - Marc Pourrier
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British ColumbiaVancouverCanada
| | - Vitya Vardanyan
- Molecular Neuroscience Group, Institute of Molecular BiologyYerevanArmenia
| | - David Fedida
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British ColumbiaVancouverCanada
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2
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O'Sullivan JW, Raghavan S, Marquez-Luna C, Luzum JA, Damrauer SM, Ashley EA, O'Donnell CJ, Willer CJ, Natarajan P. Polygenic Risk Scores for Cardiovascular Disease: A Scientific Statement From the American Heart Association. Circulation 2022; 146:e93-e118. [PMID: 35862132 PMCID: PMC9847481 DOI: 10.1161/cir.0000000000001077] [Citation(s) in RCA: 86] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Cardiovascular disease is the leading contributor to years lost due to disability or premature death among adults. Current efforts focus on risk prediction and risk factor mitigation' which have been recognized for the past half-century. However, despite advances, risk prediction remains imprecise with persistently high rates of incident cardiovascular disease. Genetic characterization has been proposed as an approach to enable earlier and potentially tailored prevention. Rare mendelian pathogenic variants predisposing to cardiometabolic conditions have long been known to contribute to disease risk in some families. However, twin and familial aggregation studies imply that diverse cardiovascular conditions are heritable in the general population. Significant technological and methodological advances since the Human Genome Project are facilitating population-based comprehensive genetic profiling at decreasing costs. Genome-wide association studies from such endeavors continue to elucidate causal mechanisms for cardiovascular diseases. Systematic cataloging for cardiovascular risk alleles also enabled the development of polygenic risk scores. Genetic profiling is becoming widespread in large-scale research, including in health care-associated biobanks, randomized controlled trials, and direct-to-consumer profiling in tens of millions of people. Thus, individuals and their physicians are increasingly presented with polygenic risk scores for cardiovascular conditions in clinical encounters. In this scientific statement, we review the contemporary science, clinical considerations, and future challenges for polygenic risk scores for cardiovascular diseases. We selected 5 cardiometabolic diseases (coronary artery disease, hypercholesterolemia, type 2 diabetes, atrial fibrillation, and venous thromboembolic disease) and response to drug therapy and offer provisional guidance to health care professionals, researchers, policymakers, and patients.
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3
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Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia despite substantial efforts to understand the pathophysiology of the condition and develop improved treatments. Identifying the underlying causative mechanisms of AF in individual patients is difficult and the efficacy of current therapies is suboptimal. Consequently, the incidence of AF is steadily rising and there is a pressing need for novel therapies. Research has revealed that defects in specific molecular pathways underlie AF pathogenesis, resulting in electrical conduction disorders that drive AF. The severity of this so-called electropathology correlates with the stage of AF disease progression and determines the response to AF treatment. Therefore, unravelling the molecular mechanisms underlying electropathology is expected to fuel the development of innovative personalized diagnostic tools and mechanism-based therapies. Moreover, the co-creation of AF studies with patients to implement novel diagnostic tools and therapies is a prerequisite for successful personalized AF management. Currently, various treatment modalities targeting AF-related electropathology, including lifestyle changes, pharmaceutical and nutraceutical therapy, substrate-based ablative therapy, and neuromodulation, are available to maintain sinus rhythm and might offer a novel holistic strategy to treat AF.
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Affiliation(s)
- Bianca J J M Brundel
- Department of Physiology, Amsterdam University Medical Centers, VU Universiteit, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.
| | - Xun Ai
- Department of Physiology and Cell Biology, College of Medicine/Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | | | - Myrthe F Kuipers
- AFIPonline.org, Atrial Fibrillation Innovation Platform, Amsterdam, Netherlands
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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4
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Iop L, Iliceto S, Civieri G, Tona F. Inherited and Acquired Rhythm Disturbances in Sick Sinus Syndrome, Brugada Syndrome, and Atrial Fibrillation: Lessons from Preclinical Modeling. Cells 2021; 10:3175. [PMID: 34831398 PMCID: PMC8623957 DOI: 10.3390/cells10113175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/03/2021] [Accepted: 11/09/2021] [Indexed: 12/12/2022] Open
Abstract
Rhythm disturbances are life-threatening cardiovascular diseases, accounting for many deaths annually worldwide. Abnormal electrical activity might arise in a structurally normal heart in response to specific triggers or as a consequence of cardiac tissue alterations, in both cases with catastrophic consequences on heart global functioning. Preclinical modeling by recapitulating human pathophysiology of rhythm disturbances is fundamental to increase the comprehension of these diseases and propose effective strategies for their prevention, diagnosis, and clinical management. In silico, in vivo, and in vitro models found variable application to dissect many congenital and acquired rhythm disturbances. In the copious list of rhythm disturbances, diseases of the conduction system, as sick sinus syndrome, Brugada syndrome, and atrial fibrillation, have found extensive preclinical modeling. In addition, the electrical remodeling as a result of other cardiovascular diseases has also been investigated in models of hypertrophic cardiomyopathy, cardiac fibrosis, as well as arrhythmias induced by other non-cardiac pathologies, stress, and drug cardiotoxicity. This review aims to offer a critical overview on the effective ability of in silico bioinformatic tools, in vivo animal studies, in vitro models to provide insights on human heart rhythm pathophysiology in case of sick sinus syndrome, Brugada syndrome, and atrial fibrillation and advance their safe and successful translation into the cardiology arena.
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Affiliation(s)
- Laura Iop
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Via Giustiniani, 2, I-35124 Padua, Italy; (S.I.); (G.C.)
| | | | | | - Francesco Tona
- Department of Cardiac Thoracic Vascular Sciences and Public Health, University of Padua, Via Giustiniani, 2, I-35124 Padua, Italy; (S.I.); (G.C.)
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5
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Wong CK, Tse HF. New methodological approaches to atrial fibrillation drug discovery. Expert Opin Drug Discov 2020; 16:319-329. [PMID: 33016154 DOI: 10.1080/17460441.2021.1826432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice and rhythm control using pharmacological agents is required in selected patients. Nonetheless, current medication is only modestly efficacious and associated with significant cardiovascular and systemic side effects. More efficacious and safe drugs are required to restore and maintain sinus rhythm in patients with AF. AREAS COVERED In this review, several potential drug targets are discussed including trans-membrane ion channels, intracellular calcium signaling, gap junction signaling, atrial inflammation and fibrosis, and the autonomic nervous system. New tools and methodologies for AF drug development are also reviewed including gene therapy, genome-guided therapy, stem cell technologies, tissue engineering, and optogenetics. EXPERT OPINION In recent decades, there has been an increased understanding of the underlying pathogenesis of AF. As a result, there is a gradual paradigm shift from focusing only on trans-membrane ion channel inhibition to developing therapeutic agents that target other underlying arrhythmogenic mechanisms. Gene therapy and genome-guided therapy are emerging as novel treatments for AF with some success in proof-of-concept studies. Recent advances in stem cell technology, tissue engineering, and optogenetics may allow more effective in-vitro drug screening than conventional methodologies.
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Affiliation(s)
- Chun-Ka Wong
- Cardiology Division, Department of Medicine, The University of Hong Kong, Hong Kong, SAR China
| | - Hung-Fat Tse
- Cardiology Division, Department of Medicine, The University of Hong Kong, Hong Kong, SAR China
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6
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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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7
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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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8
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Cheniti G, Vlachos K, Pambrun T, Hooks D, Frontera A, Takigawa M, Bourier F, Kitamura T, Lam A, Martin C, Dumas-Pommier C, Puyo S, Pillois X, Duchateau J, Klotz N, Denis A, Derval N, Jais P, Cochet H, Hocini M, Haissaguerre M, Sacher F. Atrial Fibrillation Mechanisms and Implications for Catheter Ablation. Front Physiol 2018; 9:1458. [PMID: 30459630 PMCID: PMC6232922 DOI: 10.3389/fphys.2018.01458] [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: 04/30/2018] [Accepted: 09/26/2018] [Indexed: 01/14/2023] Open
Abstract
AF is a heterogeneous rhythm disorder that is related to a wide spectrum of etiologies and has broad clinical presentations. Mechanisms underlying AF are complex and remain incompletely understood despite extensive research. They associate interactions between triggers, substrate and modulators including ionic and anatomic remodeling, genetic predisposition and neuro-humoral contributors. The pulmonary veins play a key role in the pathogenesis of AF and their isolation is associated to high rates of AF freedom in patients with paroxysmal AF. However, ablation of persistent AF remains less effective, mainly limited by the difficulty to identify the sources sustaining AF. Many theories were advanced to explain the perpetuation of this form of AF, ranging from a single localized focal and reentrant source to diffuse bi-atrial multiple wavelets. Translating these mechanisms to the clinical practice remains challenging and limited by the spatio-temporal resolution of the mapping techniques. AF is driven by focal or reentrant activities that are initially clustered in a relatively limited atrial surface then disseminate everywhere in both atria. Evidence for structural remodeling, mainly represented by atrial fibrosis suggests that reentrant activities using anatomical substrate are the key mechanism sustaining AF. These reentries can be endocardial, epicardial, and intramural which makes them less accessible for mapping and for ablation. Subsequently, early interventions before irreversible remodeling are of major importance. Circumferential pulmonary vein isolation remains the cornerstone of the treatment of AF, regardless of the AF form and of the AF duration. No ablation strategy consistently demonstrated superiority to pulmonary vein isolation in preventing long term recurrences of atrial arrhythmias. Further research that allows accurate identification of the mechanisms underlying AF and efficient ablation should improve the results of PsAF ablation.
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Affiliation(s)
- Ghassen Cheniti
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France.,Cardiology Department, Hopital Sahloul, Universite de Sousse, Sousse, Tunisia
| | - Konstantinos Vlachos
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Thomas Pambrun
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Darren Hooks
- Cardiology Department, Wellington Hospital, Wellington, New Zealand
| | - Antonio Frontera
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Masateru Takigawa
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Felix Bourier
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Takeshi Kitamura
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Anna Lam
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Claire Martin
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | | | - Stephane Puyo
- Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Xavier Pillois
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France
| | - Josselin Duchateau
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Nicolas Klotz
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Arnaud Denis
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Nicolas Derval
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Pierre Jais
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Hubert Cochet
- Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France.,Department of Cardiovascular Imaging, Hopital Haut Leveque, Bordeaux, France
| | - Meleze Hocini
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Michel Haissaguerre
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
| | - Frederic Sacher
- Cardiac Electrophysiology Department, Hopital Haut Leveque, Bordeaux, France.,Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University, Pessac, France
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9
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Whittaker DG, Colman MA, Ni H, Hancox JC, Zhang H. Human Atrial Arrhythmogenesis and Sinus Bradycardia in KCNQ1-Linked Short QT Syndrome: Insights From Computational Modelling. Front Physiol 2018; 9:1402. [PMID: 30337886 PMCID: PMC6180159 DOI: 10.3389/fphys.2018.01402] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/14/2018] [Indexed: 11/25/2022] Open
Abstract
Atrial fibrillation (AF) and sinus bradycardia have been reported in patients with short QT syndrome variant 2 (SQT2), which is underlain by gain-of-function mutations in KCNQ1 encoding the α subunit of channels carrying slow delayed rectifier potassium current, IKs. However, the mechanism(s) underlying the increased atrial arrhythmogenesis and impaired cardiac pacemaking activity arising from increased IKs remain unclear. Possible pharmacological interventions of AF in the SQT2 condition also remain to be elucidated. Using computational modelling, we assessed the functional impact of SQT2 mutations on human sinoatrial node (SAN) pacemaking, atrial repolarisation and arrhythmogenesis, and efficacy of the anti-arrhythmic drug quinidine. Markov chain formulations of IKs describing two KCNQ1 mutations – V141M and V307L – were developed from voltage-clamp experimental data and then incorporated into contemporary action potential (AP) models of human atrial and SAN cells, the former of which were integrated into idealised and anatomically detailed tissue models. Both mutations shortened atrial AP duration (APD) through distinct IKs ‘gain-of-function’ mechanisms, whereas SAN pacemaking rate was slowed markedly only by the V141M mutation. Differences in APD restitution steepness influenced re-entry dynamics in tissue – the V141M mutation promoted stationary and stable spiral waves whereas the V307L mutation promoted non-stationary and unstable re-entrant waves. Both mutations shortened tissue excitation wavelength through reduced effective refractory period but not conduction velocity, which served to increase the lifespan of re-entrant excitation in a 3D anatomical human atria model, as well as the dominant frequency (DF), which was higher for the V141M mutation. Quinidine was effective at terminating arrhythmic excitation waves associated with the V307L but not V141M mutation, and reduced the DF in a dose-dependent manner under both mutation conditions. This study provides mechanistic insights into different AF/bradycardia phenotypes in SQT2 and the efficacy of quinidine pharmacotherapy.
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Affiliation(s)
- Dominic G Whittaker
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.,Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Michael A Colman
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Haibo Ni
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Jules C Hancox
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,School of Physiology, Pharmacology and Neuroscience, and Cardiovascular Research Laboratories, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Henggui Zhang
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom.,School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.,Space Institute of Southern China, Shenzhen, China.,Key Laboratory of Medical Electrophysiology, Ministry of Education, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease/Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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10
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Abstract
PURPOSE OF REVIEW To describe recent findings regarding the role of rare and common genetic variants in atrial fibrillation. RECENT FINDINGS Atrial fibrillation is associated with several clinical risk factors and its development is affected by genetic background. To date, rare variants from more than 30 genes have been identified from studies of familial cases or individuals with lone atrial fibrillation. In addition to using the candidate gene approach for the identification of rare variants, next-generation sequencing approaches such as genomic, whole exome and targeted sequencing have been employed. Furthermore, evidence of association between common variants and atrial fibrillation has been discovered through genome-wide association studies. Although the power of any one single-nucleotide polymorphism (SNP) associated with atrial fibrillation is weak, a genetic risk score comprising 12 SNPs may identify individuals at an increased risk for atrial fibrillation. This SNP panel may also delineate genotypes to enable stratification of atrial fibrillation ablation therapy or periinterventional management. SUMMARY Although studies have demonstrated that atrial fibrillation is highly heritable, many aspects of atrial fibrillation remain unknown. Rigorous research efforts continue with the expectation that the contribution of variants and candidate genes that contribute to the overall genetic architecture of atrial fibrillation will be identified and characterized in the coming years.
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11
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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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12
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Villatoro-Gómez K, Pacheco-Rojas DO, Moreno-Galindo EG, Navarro-Polanco RA, Tristani-Firouzi M, Gazgalis D, Cui M, Sánchez-Chapula JA, Ferrer T. Molecular determinants of Kv7.1/KCNE1 channel inhibition by amitriptyline. Biochem Pharmacol 2018; 152:264-271. [PMID: 29621539 DOI: 10.1016/j.bcp.2018.03.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/15/2018] [Indexed: 12/11/2022]
Abstract
Amitriptyline (AMIT) is a compound widely prescribed for psychiatric and non-psychiatric conditions including depression, migraine, chronic pain, and anorexia. However, AMIT has been associated with risks of cardiac arrhythmia and sudden death since it can induce prolongation of the QT interval on the surface electrocardiogram and torsade de pointes ventricular arrhythmia. These complications have been attributed to the inhibition of the rapid delayed rectifier potassium current (IKr). The slow delayed rectifier potassium current (IKs) is the main repolarizing cardiac current when IKr is compromised and it has an important role in cardiac repolarization at fast heart rates induced by an elevated sympathetic tone. Therefore, we sought to characterize the effects of AMIT on Kv7.1/KCNE1 and homomeric Kv7.1 channels expressed in HEK-293H cells. Homomeric Kv7.1 and Kv7.1/KCNE1 channels were inhibited by AMIT in a concentration-dependent manner with IC50 values of 8.8 ± 2.1 μM and 2.5 ± 0.8 μM, respectively. This effect was voltage-independent for both homomeric Kv7.1 and Kv7.1/KCNE1 channels. Moreover, mutation of residues located on the P-loop and S6 domain along with molecular docking, suggest that T312, I337 and F340 are the most important molecular determinants for AMIT-Kv7.1 channel interaction. Our experimental findings and modeling suggest that AMIT preferentially blocks the open state of Kv7.1/KCNE1 channels by interacting with specific residues that were previously reported to be important for binding of other compounds, such as chromanol 293B and the benzodiazepine L7.
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Affiliation(s)
- Kathya Villatoro-Gómez
- Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Col., Mexico
| | - David O Pacheco-Rojas
- Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Col., Mexico
| | - Eloy G Moreno-Galindo
- Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Col., Mexico
| | - Ricardo A Navarro-Polanco
- Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Col., Mexico
| | - Martin Tristani-Firouzi
- Nora Eccles Harrison CVRTI, University of Utah School of Medicine, Salt Lake City, UT 84112, USA; Division of Pediatric Cardiology, University of Utah School of Medicine, Salt Lake City, UT 83113, USA
| | - Dimitris Gazgalis
- Department of Pharmaceutical Sciences, Northeastern University School of Pharmacy, Boston, MA 02115, USA
| | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University School of Pharmacy, Boston, MA 02115, USA
| | - José A Sánchez-Chapula
- Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Col., Mexico
| | - Tania Ferrer
- Centro Universitario de Investigaciones Biomédicas de la Universidad de Colima, Colima, Col., Mexico.
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Barrese V, Stott JB, Greenwood IA. KCNQ-Encoded Potassium Channels as Therapeutic Targets. Annu Rev Pharmacol Toxicol 2018; 58:625-648. [DOI: 10.1146/annurev-pharmtox-010617-052912] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | | | - Iain A. Greenwood
- Vascular Biology Research Centre, Molecular and Clinical Sciences Institute, St George's, University of London, London, SW17 0RE, United Kingdom;, ,
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14
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Gating mechanisms underlying deactivation slowing by two KCNQ1 atrial fibrillation mutations. Sci Rep 2017; 7:45911. [PMID: 28383569 PMCID: PMC5382920 DOI: 10.1038/srep45911] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/03/2017] [Indexed: 01/13/2023] Open
Abstract
KCNQ1 is a voltage-gated potassium channel that is modulated by the beta-subunit KCNE1 to generate IKs, the slow delayed rectifier current, which plays a critical role in repolarizing the cardiac action potential. Two KCNQ1 gain-of-function mutations that cause a genetic form of atrial fibrillation, S140G and V141M, drastically slow IKs deactivation. However, the underlying gating alterations remain unknown. Voltage clamp fluorometry (VCF) allows simultaneous measurement of voltage sensor movement and current through the channel pore. Here, we use VCF and kinetic modeling to determine the effects of mutations on channel voltage-dependent gating. We show that in the absence of KCNE1, S140G, but not V141M, directly slows voltage sensor movement, which indirectly slows current deactivation. In the presence of KCNE1, both S140G and V141M slow pore closing and alter voltage sensor-pore coupling, thereby slowing current deactivation. Our results suggest that KCNE1 can mediate changes in pore movement and voltage sensor-pore coupling to slow IKs deactivation and provide a key step toward developing mechanism-based therapies.
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The Role of Pharmacogenetics in Atrial Fibrillation Therapeutics: Is Personalized Therapy in Sight? J Cardiovasc Pharmacol 2016; 67:9-18. [PMID: 25970841 DOI: 10.1097/fjc.0000000000000280] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia worldwide requiring therapy. Despite recent advances in catheter-based and surgical therapy, antiarrhythmic drugs (AADs) remain the mainstay of treatment for symptomatic AF. However, response in individual patients is highly variable with over half the patients treated with rhythm control therapy experiencing recurrence of AF within a year. Contemporary AADs used to suppress AF are incompletely and unpredictably effective and associated with significant risks of proarrhythmia and noncardiac toxicities. Furthermore, this "one-size" fits all strategy for selecting antiarrhythmics is based largely on minimizing risk of adverse effects rather than on the likelihood of suppressing AF. The limited success of rhythm control therapy is in part due to heterogeneity of the underlying substrate, interindividual differences in disease mechanisms, and our inability to predict response to AADs in individual patients. Genetic studies of AF over the past decade have revealed that susceptibility to and response to therapy for AF is modulated by the underlying genetic substrate. However, the bedside application of these new discoveries to the management of AF patients has thus far been disappointing. This may in part be related to our limited understanding about genetic predictors of drug response in general, the challenges associated with determining efficacy of response to AADs, and lack of randomized genotype-directed clinical trials. Nonetheless, recent studies have shown that common AF susceptibility risk alleles at the chromosome 4q25 locus modulated response to AADs, electrical cardioversion, and ablation therapy. This monograph discusses how genetic approaches to AF have not only provided important insights into underlying mechanisms but also identified AF subtypes that can be better targeted with more mechanism-based "personalized" therapy.
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Rothenberg I, Piccini I, Wrobel E, Stallmeyer B, Müller J, Greber B, Strutz-Seebohm N, Schulze-Bahr E, Schmitt N, Seebohm G. Structural interplay of K V7.1 and KCNE1 is essential for normal repolarization and is compromised in short QT syndrome 2 (K V7.1-A287T). HeartRhythm Case Rep 2016; 2:521-529. [PMID: 28491751 PMCID: PMC5420010 DOI: 10.1016/j.hrcr.2016.08.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Ina Rothenberg
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
| | - Ilaria Piccini
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
| | - Eva Wrobel
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
| | - Birgit Stallmeyer
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
| | - Jovanca Müller
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
| | - Boris Greber
- Human Stem Cell Pluripotency Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Chemical Genomics Centre of the Max Planck Society, Dortmund, Germany
| | - Nathalie Strutz-Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
| | - Eric Schulze-Bahr
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
- Interdisziplinäres Zentrum für Klinische Forschung Münster (IZKF Münster) and Innovative Medizinische Forschung (IMF Münster), Faculty of Medicine, University of Münster, Münster, Germany
| | - Nicole Schmitt
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, Münster, Germany
- Interdisziplinäres Zentrum für Klinische Forschung Münster (IZKF Münster) and Innovative Medizinische Forschung (IMF Münster), Faculty of Medicine, University of Münster, Münster, Germany
- Address reprint requests and correspondence: Dr Guiscard Seebohm, Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D48149 Münster, Germany.Institute for Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, D48149MünsterGermany
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17
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Abstract
INTRODUCTION Over the last decade, tremendous progress has been made in defining the genetic architecture of atrial fibrillation (AF). This has in part been driven by poor understanding of the pathophysiology of AF, limitations of current therapies and failure to target therapies to the underlying mechanisms. AREAS COVERED Genetic approaches to AF have identified mutations encoding cardiac ion channels, and signaling proteins linked with AF and genome-wide association studies have uncovered common genetic variants modulating AF risk. These studies have provided important insights into the underlying mechanisms of AF and defined responses to therapies. Common AF-risk alleles at the chromosome 4q25 locus modulate response to antiarrhythmic drugs, electrical cardioversion and catheter ablation. While the translation of these discoveries to the bedside care of individual patients has been limited, emerging evidence supports the hypothesis that genotype-directed approaches that target the underlying mechanisms of AF may not only improve therapeutic efficacy but also minimize adverse effects. Expert commentary: There is an urgent need for randomized controlled trials that are genotype-based for the treatment of AF. Nonetheless, emerging data suggest that selecting therapies for AF that are genotype-directed may soon be upon us.
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Affiliation(s)
- Henry Huang
- a Division of Cardiology, Department of Medicine , University of Illinois at Chicago , Chicago , IL , USA
| | - Dawood Darbar
- a Division of Cardiology, Department of Medicine , University of Illinois at Chicago , Chicago , IL , USA
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18
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Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia despite substantial efforts to understand the pathophysiology of the condition and develop improved treatments. Identifying the underlying causative mechanisms of AF in individual patients is difficult and the efficacy of current therapies is suboptimal. Consequently, the incidence of AF is steadily rising and there is a pressing need for novel therapies. Research has revealed that defects in specific molecular pathways underlie AF pathogenesis, resulting in electrical conduction disorders that drive AF. The severity of this so-called electropathology correlates with the stage of AF disease progression and determines the response to AF treatment. Therefore, unravelling the molecular mechanisms underlying electropathology is expected to fuel the development of innovative personalized diagnostic tools and mechanism-based therapies. Moreover, the co-creation of AF studies with patients to implement novel diagnostic tools and therapies is a prerequisite for successful personalized AF management. Currently, various treatment modalities targeting AF-related electropathology, including lifestyle changes, pharmaceutical and nutraceutical therapy, substrate-based ablative therapy, and neuromodulation, are available to maintain sinus rhythm and might offer a novel holistic strategy to treat AF.
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Affiliation(s)
- Bianca J. J. M. Brundel
- Department of Physiology, Amsterdam University Medical Centers, VU Universiteit, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,
| | - Xun Ai
- Department of Physiology and Cell Biology, College of Medicine/Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | | | - Myrthe F. Kuipers
- AFIPonline.org, Atrial Fibrillation Innovation Platform, Amsterdam, Netherlands
| | - Gregory Y. H. Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK.,Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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19
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Seccia TM, Caroccia B, Muiesan ML, Rossi GP. Atrial fibrillation and arterial hypertension: A common duet with dangerous consequences where the renin angiotensin-aldosterone system plays an important role. Int J Cardiol 2016; 206:71-6. [PMID: 26774837 DOI: 10.1016/j.ijcard.2016.01.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 11/24/2015] [Accepted: 01/01/2016] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) represents the most common sustained cardiac arrhythmia, as it affects 1%-2% of the general population and up to 15% of people over 80 years. High blood pressure, due to its high prevalence in the general population, is by far the most common condition associated with AF, although a variety of diseases, including valvular, coronary heart and metabolic diseases, are held to create the substrate favouring AF. Due to the concomitance of these conditions, it is quite challenging to dissect the precise role of high blood pressure in triggering/causing AF. Hence, even though the intimate association between high blood pressure and AF has been known for decades, the underlying mechanisms remain partially unknown. Accumulating evidences point to a major role of the renin-angiotensin-aldosterone system in inducing cardiac inflammation and fibrosis, and therefore electric and structural atrial and ventricular remodelling, with changes in ions and cell junctions leading to AF development. These evidences are herein reviewed with a particular emphasis to the role of the renin-angiotensin-system aldosterone system.
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20
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Hayashi K, Konno T, Tada H, Tani S, Liu L, Fujino N, Nohara A, Hodatsu A, Tsuda T, Tanaka Y, Kawashiri MA, Ino H, Makita N, Yamagishi M. Functional Characterization of Rare Variants Implicated in Susceptibility to Lone Atrial Fibrillation. Circ Arrhythm Electrophysiol 2015; 8:1095-104. [PMID: 26129877 DOI: 10.1161/circep.114.002519] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 06/19/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Few rare variants in atrial fibrillation (AF)-associated genes have been functionally characterized to identify a causal relationship between these variants and development of AF. We here sought to determine the clinical effect of rare variants in AF-associated genes in patients with lone AF and characterized these variants electrophysiologically and bioinformatically. METHODS AND RESULTS We screened all coding regions in 12 AF-associated genes in 90 patients with lone AF, with an onset of 47±11 years (66 men; mean age, 56±13 years) by high-resolution melting curve analysis and DNA sequencing. The potassium and sodium currents were analyzed using whole-cell patch clamping. In addition to using 4 individual in silico prediction tools, we extended those predictions to an integrated tool (Combined Annotation Dependent Depletion). We identified 7 rare variants in KCNA5, KCNQ1, KCNH2, SCN5A, and SCN1B genes in 8 patients: 2 of 8 probands had a family history of AF. Electrophysiological studies revealed that 2 variants showed a loss-of-function, and 4 variants showed a gain-of-function. Five of 6 variants with electrophysiological abnormalities were predicted as pathogenic by Combined Annotation Dependent Depletion scores. CONCLUSIONS In our cohort of patients with lone AF, 7 rare variants in cardiac ion channels were identified in 8 probands. A combination of electrophysiological studies and in silico predictions showed that these variants could contribute to the development of lone AF, although further in vivo study is necessary to confirm these results. More than half of AF-associated rare variants showed gain-of-function behavior, which may be targeted using genotype-specific pharmacological therapy.
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Affiliation(s)
- Kenshi Hayashi
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.).
| | - Tetsuo Konno
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Hayato Tada
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Satoyuki Tani
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Li Liu
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Noboru Fujino
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Atsushi Nohara
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Akihiko Hodatsu
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Toyonobu Tsuda
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Yoshihiro Tanaka
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Masa-aki Kawashiri
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Hidekazu Ino
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Naomasa Makita
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
| | - Masakazu Yamagishi
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (K.H., T.K., H.T., S.T., L.L., N.F., A.N., A.H., T.T., Y.T., M.K., M.Y.); Department of Cardiology, Komatsu Municipal Hospital, Komatsu, Japan (H.I.); and Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan (N.M.)
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Dvir M, Peretz A, Haitin Y, Attali B. Recent molecular insights from mutated IKS channels in cardiac arrhythmia. Curr Opin Pharmacol 2013; 15:74-82. [PMID: 24721657 DOI: 10.1016/j.coph.2013.12.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 12/04/2013] [Accepted: 12/06/2013] [Indexed: 12/19/2022]
Abstract
Co-assembly of KCNQ1 with KCNE1 generates the IKS potassium current that is vital for the proper repolarization of the cardiac action potential. Mutations in either KCNQ1 or KCNE1 genes lead to life-threatening cardiac arrhythmias causing long QT syndrome, short QT syndrome, sinus bradycardia and atrial fibrillation. Findings emerging from recent studies are beginning to provide a picture of how gain-of-function and loss-of-function mutations are associated with pleiotropic cardiac phenotypes in the clinics. In this review, we discuss recent molecular insights obtained from mutations altering different structural modules of the channel complex that are essential for proper IKS function. We present the possible molecular mechanisms underlying mutations impairing the voltage sensing functions, as well as those altering the channel regulation by phosphatidylinositol-4,5-bisphosphate, calmodulin and protein kinase A. We also discuss the significance of diseased IKS channels for adequate pharmacological targeting of cardiac arrhythmias.
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Affiliation(s)
- Meidan Dvir
- Department of Physiology & Pharmacology, The Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Asher Peretz
- Department of Physiology & Pharmacology, The Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Yoni Haitin
- Department of Physiology & Pharmacology, The Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Bernard Attali
- Department of Physiology & Pharmacology, The Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel.
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22
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Hasegawa K, Ohno S, Ashihara T, Itoh H, Ding WG, Toyoda F, Makiyama T, Aoki H, Nakamura Y, Delisle BP, Matsuura H, Horie M. A novel KCNQ1 missense mutation identified in a patient with juvenile-onset atrial fibrillation causes constitutively open IKs channels. Heart Rhythm 2013; 11:67-75. [PMID: 24096004 DOI: 10.1016/j.hrthm.2013.09.073] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Indexed: 12/19/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is one of the most common cardiac arrhythmias. In some patients, the disease is inheritable; however, hereditary aspects of AF remain not fully elucidated. OBJECTIVE The purpose of this study was to identify genetic backgrounds that contribute to juvenile-onset AF and to define the mechanism. METHODS In 30 consecutive juvenile-onset AF patients (onset age <50 years), we screened AF-related genes (KCNQ1, KCNH2, KCNE1-3, KCNE5, KCNJ2, SCN5A). We analyzed the function of mutant channels using whole-cell patch-clamp techniques and computer simulations. RESULTS Among the juvenile-onset AF patients, we identified three mutations (10%): SCN5A-M1875T, KCNJ2-M301K, and KCNQ1-G229D. Because KCNQ1 variant (G229D) identified in a 16-year-old boy was novel, we focused on the proband. The G229D-IKs was found to induce a large instantaneous activating component without deactivation after repolarization to -50 mV. In addition, wild-type (WT)/G229D-IKs (WT and mutant coexpression) displayed both instantaneous and time-dependent activating currents. Compared to WT-IKs, the tail current densities in WT/G229D-IKs were larger at test potentials between -130 and -40 mV but smaller at test potentials between 20 and 50 mV. Moreover, WT/G229D-IKs resulted in a negative voltage shift for current activation (-35.2 mV) and slower deactivation. WT/G229D-IKs conducted a large outward current induced by an atrial action potential waveform, and computer simulation incorporating the WT/G229D-IKs results revealed that the mutation shortened atrial but not ventricular action potential. CONCLUSION A novel KCNQ1-G229D mutation identified in a juvenile-onset AF patient altered the IKs activity and kinetics, thereby increasing the arrhythmogenicity to AF.
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Affiliation(s)
- Kanae Hasegawa
- Department of Cardiovascular Biology and Medicine, Niigata University School of Medical and Dental Sciences, Niigata, Japan; Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Seiko Ohno
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Takashi Ashihara
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Hideki Itoh
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Wei-Guang Ding
- Department of Physiology, Shiga University of Medical Science, Otsu, Japan
| | - Futoshi Toyoda
- Department of Physiology, Shiga University of Medical Science, Otsu, Japan
| | - Takeru Makiyama
- Department of Cardiovascular and Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hisaaki Aoki
- Department of Pediatrics, Kinki University Faculty Medicine, Osaka, Japan
| | - Yoshihide Nakamura
- Department of Pediatrics, Kinki University Faculty Medicine, Osaka, Japan
| | - Brian P Delisle
- Department of Physiology, University of Kentucky, Lexington, Kentucky
| | - Hiroshi Matsuura
- Department of Physiology, Shiga University of Medical Science, Otsu, Japan
| | - Minoru Horie
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan.
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