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Rahman RA, Zaman B, Khan MR, Islam MS, Rashid MH. Computational Studies Show How the H463R Mutation Turns hKv1.5 into an Inactivation State. J Phys Chem B 2024; 128:429-439. [PMID: 38179652 DOI: 10.1021/acs.jpcb.3c05634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
The KCNA5 gene provides the code for the α-subunit of the potassium channel Kv1.5. The genetic variant H463R in the Kv1.5 channel has been reported to cause a functional loss in atrial fibrillation (AF) patients. Understanding the mutations at a molecular level is key to developing improved therapeutics concerning cardiac hKv1.5 and hKv1.4 channels. Molecular dynamics and umbrella sampling free energy simulations are an effective tool to understand the mutation's effect on ion conduction, which we have employed and found that the hKv1.5[H463R] mutation imposes an energy barrier on the ion conduction pathway compared to the wild-type channel's ion free energy and pore structure. These results imply that the arginine mutation associated with the AF disease in particular modulates the inactivation process of hKv1.5. Kv1.4, encoded by the KCNA4 gene, is also present in the heart. Therefore, we considered simulation studies of the equivalent H507R mutation in the hKv1.4 channel and found that the mutation slightly reduces the ion conduction barrier in the ion conduction pathway, making it insignificant.
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Affiliation(s)
- Ramisha A Rahman
- Department of Mathematics & Physics, North South University, Plot # 15, Dhaka 1229, Bangladesh
| | - Bushra Zaman
- Department of Mathematics & Physics, North South University, Plot # 15, Dhaka 1229, Bangladesh
| | - Mohammad Radid Khan
- Department of Mathematics & Physics, North South University, Plot # 15, Dhaka 1229, Bangladesh
| | - Md Shariful Islam
- Department of Mathematics & Physics, North South University, Plot # 15, Dhaka 1229, Bangladesh
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003, United States
| | - Md Harunur Rashid
- Department of Mathematics & Physics, North South University, Plot # 15, Dhaka 1229, Bangladesh
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2
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Hwang S, Yoon B, Jo SH. Inhibitory effects of N-methyl-D-aspartate (NMDA) and α 1-adrenergic receptor antagonist ifenprodil on human Kv1.5 channel. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2023; 396:3149-3161. [PMID: 37166464 DOI: 10.1007/s00210-023-02521-6] [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: 12/12/2022] [Accepted: 05/04/2023] [Indexed: 05/12/2023]
Abstract
Ifenprodil has been known to reduce cardiac contractility and cerebral vasodilation by antagonizing α1-adrenergic and N-methyl D-aspartate receptor-mediated intracellular signals. This study aimed to investigate the direct effect of ifenprodil on the human voltage-gated Kv1.5 channel (hKv1.5) by using a Xenopus oocyte expression system and a two-microelectrode voltage clamp technique. The amplitudes of hKv1.5 currents, including peak and steady state, were suppressed in a concentration-dependent manner (IC50; 43.1 and 35.5 μM, respectively) after 6 min of ifenprodil treatment. However, these effects were ~ 80% reversed by washout, suggesting that ifenprodil directly inhibited the hKv1.5 independent of membrane receptors or intracellular signals. The inhibition rate of steady state showed voltage dependence, wherein the rates increased according to test voltage depolarization. Ifenprodil reduced the time constants of hKv1.5 inactivation but has higher effects on activation. hKv1.5 inhibition by ifenprodil showed use dependency because the drug more rapidly reduced the current at the higher activation frequencies, and subsequent reduction in frequency after high activation frequency caused a partial channel block relief. Therefore, ifenprodil directly blocked the hKv1.5 in an open state and accelerated the time course of the channel inactivation, which provided a biophysical mechanism for the hKv1.5 blocking effects of ifenprodil.
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Affiliation(s)
- Soobeen Hwang
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 plus Graduate Program, Kangwon National University College of Medicine, Hyoja-Dong, Chuncheon, 200-701, Korea
| | - Byeongjun Yoon
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 plus Graduate Program, Kangwon National University College of Medicine, Hyoja-Dong, Chuncheon, 200-701, Korea
| | - Su-Hyun Jo
- Department of Physiology, Institute of Bioscience and Biotechnology, BK21 plus Graduate Program, Kangwon National University College of Medicine, Hyoja-Dong, Chuncheon, 200-701, Korea.
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3
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Al-Owais MM, Hettiarachchi NT, Dallas ML, Scragg JL, Lippiat JD, Holden AV, Steele DS, Peers C. Inhibition of the voltage-gated potassium channel Kv1.5 by hydrogen sulfide attenuates remodeling through S-nitrosylation-mediated signaling. Commun Biol 2023; 6:651. [PMID: 37336943 PMCID: PMC10279668 DOI: 10.1038/s42003-023-05016-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 06/05/2023] [Indexed: 06/21/2023] Open
Abstract
The voltage-gated K+ channel plays a key role in atrial excitability, conducting the ultra-rapid rectifier K+ current (IKur) and contributing to the repolarization of the atrial action potential. In this study, we examine its regulation by hydrogen sulfide (H2S) in HL-1 cardiomyocytes and in HEK293 cells expressing human Kv1.5. Pacing induced remodeling resulted in shorting action potential duration, enhanced both Kv1.5 channel and H2S producing enzymes protein expression in HL-1 cardiomyocytes. H2S supplementation reduced these remodeling changes and restored action potential duration through inhibition of Kv1.5 channel. H2S also inhibited recombinant hKv1.5, lead to nitric oxide (NO) mediated S-nitrosylation and activated endothelial nitric oxide synthase (eNOS) by increased phosphorylation of Ser1177, prevention of NO formation precluded these effects. Regulation of Ikur by H2S has important cardiovascular implications and represents a novel and potential therapeutic target.
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Affiliation(s)
- Moza M Al-Owais
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| | - Nishani T Hettiarachchi
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, UK
| | - Mark L Dallas
- Reading School of Pharmacy, University of Reading, Reading, RG6 6UB, UK
| | - Jason L Scragg
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, UK
| | - Jonathan D Lippiat
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Arun V Holden
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Derek S Steele
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Chris Peers
- Division of Cardiovascular and Diabetes Research, LICAMM, Faculty of Medicine and Health, University of Leeds, Leeds, LS2 9JT, UK
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4
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Salvage SC, Jeevaratnam K, Huang CL, Jackson AP. Cardiac sodium channel complexes and arrhythmia: structural and functional roles of the β1 and β3 subunits. J Physiol 2023; 601:923-940. [PMID: 36354758 PMCID: PMC10953345 DOI: 10.1113/jp283085] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/04/2022] [Indexed: 11/12/2022] Open
Abstract
In cardiac myocytes, the voltage-gated sodium channel NaV 1.5 opens in response to membrane depolarisation and initiates the action potential. The NaV 1.5 channel is typically associated with regulatory β-subunits that modify gating and trafficking behaviour. These β-subunits contain a single extracellular immunoglobulin (Ig) domain, a single transmembrane α-helix and an intracellular region. Here we focus on the role of the β1 and β3 subunits in regulating NaV 1.5. We catalogue β1 and β3 domain specific mutations that have been associated with inherited cardiac arrhythmia, including Brugada syndrome, long QT syndrome, atrial fibrillation and sudden death. We discuss how new structural insights into these proteins raises new questions about physiological function.
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Affiliation(s)
| | | | - Christopher L.‐H. Huang
- Department of BiochemistryUniversity of CambridgeCambridgeUK
- Department of PhysiologyDevelopment and NeuroscienceUniversity of CambridgeCambridgeUK
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5
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Alameh M, Oliveira-Mendes BR, Kyndt F, Rivron J, Denjoy I, Lesage F, Schott JJ, De Waard M, Loussouarn G. A need for exhaustive and standardized characterization of ion channels activity. The case of K V11.1. Front Physiol 2023; 14:1132533. [PMID: 36860515 PMCID: PMC9968853 DOI: 10.3389/fphys.2023.1132533] [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: 12/27/2022] [Accepted: 01/30/2023] [Indexed: 02/16/2023] Open
Abstract
hERG, the pore-forming subunit of the rapid component of the delayed rectifier K+ current, plays a key role in ventricular repolarization. Mutations in the KCNH2 gene encoding hERG are associated with several cardiac rhythmic disorders, mainly the Long QT syndrome (LQTS) characterized by prolonged ventricular repolarization, leading to ventricular tachyarrhythmias, sometimes progressing to ventricular fibrillation and sudden death. Over the past few years, the emergence of next-generation sequencing has revealed an increasing number of genetic variants including KCNH2 variants. However, the potential pathogenicity of the majority of the variants remains unknown, thus classifying them as variants of uncertain significance or VUS. With diseases such as LQTS being associated with sudden death, identifying patients at risk by determining the variant pathogenicity, is crucial. The purpose of this review is to describe, on the basis of an exhaustive examination of the 1322 missense variants, the nature of the functional assays undertaken so far and their limitations. A detailed analysis of 38 hERG missense variants identified in Long QT French patients and studied in electrophysiology also underlies the incomplete characterization of the biophysical properties for each variant. These analyses lead to two conclusions: first, the function of many hERG variants has never been looked at and, second, the functional studies done so far are excessively heterogeneous regarding the stimulation protocols, cellular models, experimental temperatures, homozygous and/or the heterozygous condition under study, a context that may lead to conflicting conclusions. The state of the literature emphasizes how necessary and important it is to perform an exhaustive functional characterization of hERG variants and to standardize this effort for meaningful comparison among variants. The review ends with suggestions to create a unique homogeneous protocol that could be shared and adopted among scientists and that would facilitate cardiologists and geneticists in patient counseling and management.
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Affiliation(s)
- Malak Alameh
- CNRS, INSERM, l’institut du thorax, Nantes Université, CHU Nantes, Nantes, France,Labex ICST, INSERM, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d’Azur, Valbonne, France
| | - Barbara Ribeiro Oliveira-Mendes
- CNRS, INSERM, l’institut du thorax, Nantes Université, CHU Nantes, Nantes, France,*Correspondence: Barbara Ribeiro Oliveira-Mendes,
| | - Florence Kyndt
- CNRS, INSERM, l’institut du thorax, Nantes Université, CHU Nantes, Nantes, France
| | - Jordan Rivron
- CNRS, INSERM, l’institut du thorax, Nantes Université, CHU Nantes, Nantes, France
| | - Isabelle Denjoy
- Service de Cardiologie et CNMR Maladies Cardiaques Héréditaires Rares, Hôpital Bichat, Paris, France
| | - Florian Lesage
- Labex ICST, INSERM, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d’Azur, Valbonne, France
| | - Jean-Jacques Schott
- CNRS, INSERM, l’institut du thorax, Nantes Université, CHU Nantes, Nantes, France
| | - Michel De Waard
- CNRS, INSERM, l’institut du thorax, Nantes Université, CHU Nantes, Nantes, France,Labex ICST, INSERM, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d’Azur, Valbonne, France
| | - Gildas Loussouarn
- CNRS, INSERM, l’institut du thorax, Nantes Université, CHU Nantes, Nantes, France
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Lin L, Li K, Tian B, Jia M, Wang Q, Xu C, Xiong L, Wang Q, Zeng Y, Wang P. Two Novel Functional Mutations in Promoter Region of SCN3B Gene Associated with Atrial Fibrillation. Life (Basel) 2022; 12:life12111794. [PMID: 36362949 PMCID: PMC9698146 DOI: 10.3390/life12111794] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/01/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
The sodium voltage-gated channel beta subunit 3 (SCN3B) plays a crucial role in electrically excitable cells and conduction tissue in the heart. Some previous studies have established that genetic modification in sodium voltage-channel genes encoding for the cardiac β-subunits, such as SCN1B, SCN2B, SCN3B and SCN4B, can result in atrial fibrillation (AF). In the current study, we identified two rare variants in 5′UTR (NM_018400.4: c.-324C>A, rs976125894 and NM_018400.4: c.-303C>T, rs1284768362) of SCN3B in two unrelated lone AF patients. Our further functional studies discovered that one of them, the A allele of c.-324C>A (rs976125894), can improve transcriptional activity and may raise SCN3B expression levels. The A allele of c.-324C>A (rs976125894) has higher transcriptional activity when it interacts with GATA4, as we confirmed transcription factor GATA4 is a regulator of SCN3B. To the best of our knowledge, the current study is the first to demonstrate that the gain-of-function mutation of SCN3B can produce AF and the first to link a mutation occurring in the non-coding 5′UTR region of SCN3B to lone AF. The work also offers empirical proof that GATA4 is a critical regulator of SCN3B gene regulation. Our findings may serve as an encyclopedia for AF susceptibility variants and can also provide insight into the investigation of the functional mechanisms behind AF variants discovered by genetic methods.
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Affiliation(s)
- Liyan Lin
- Department of Clinical Laboratory, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430077, China
| | - Ke Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Cardio-X Institute, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Human Genome Research Center, College of Life and Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Beijia Tian
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Cardio-X Institute, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Human Genome Research Center, College of Life and Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Mengru Jia
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Cardio-X Institute, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Human Genome Research Center, College of Life and Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qianyan Wang
- Liyuan Cardiovascular Center, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430077, China
| | - Chengqi Xu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Cardio-X Institute, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Human Genome Research Center, College of Life and Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Liang Xiong
- Department of Clinical Laboratory, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430077, China
| | - Qing Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Cardio-X Institute, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
- Human Genome Research Center, College of Life and Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yali Zeng
- Department of Clinical Laboratory, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430077, China
- Correspondence: (Y.Z.); (P.W.)
| | - Pengyun Wang
- Department of Clinical Laboratory, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430077, China
- Correspondence: (Y.Z.); (P.W.)
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7
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Ramos-Mondragon R, Edokobi N, Hodges SL, Wang S, Bouza AA, Canugovi C, Scheuing C, Juratli L, Abel WR, Noujaim SF, Madamanchi NR, Runge MS, Lopez-Santiago LF, Isom LL. Neonatal Scn1b-null mice have sinoatrial node dysfunction, altered atrial structure, and atrial fibrillation. JCI Insight 2022; 7:152050. [PMID: 35603785 PMCID: PMC9220823 DOI: 10.1172/jci.insight.152050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 04/12/2022] [Indexed: 11/17/2022] Open
Abstract
Loss-of-function (LOF) variants in SCN1B, encoding the voltage-gated sodium channel β1/β1B subunits, are linked to neurological and cardiovascular diseases. Scn1b-null mice have spontaneous seizures and ventricular arrhythmias and die by approximately 21 days after birth. β1/β1B Subunits play critical roles in regulating the excitability of ventricular cardiomyocytes and maintaining ventricular rhythmicity. However, whether they also regulate atrial excitability is unknown. We used neonatal Scn1b-null mice to model the effects of SCN1B LOF on atrial physiology in pediatric patients. Scn1b deletion resulted in altered expression of genes associated with atrial dysfunction. Scn1b-null hearts had a significant accumulation of atrial collagen, increased susceptibility to pacing induced atrial fibrillation (AF), sinoatrial node (SAN) dysfunction, and increased numbers of cholinergic neurons in ganglia that innervate the SAN. Atropine reduced the incidence of AF in null animals. Action potential duration was prolonged in null atrial myocytes, with increased late sodium current density and reduced L-type calcium current density. Scn1b LOF results in altered atrial structure and AF, demonstrating the critical role played by Scn1b in atrial physiology during early postnatal mouse development. Our results suggest that SCN1B LOF variants may significantly impact the developing pediatric heart.
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Affiliation(s)
| | | | | | | | | | - Chandrika Canugovi
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | | | | | - Sami F. Noujaim
- Department of Molecular Pharmacology & Physiology, University of South Florida College of Medicine, Tampa, Florida, USA
| | - Nageswara R. Madamanchi
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Marschall S. Runge
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Lori L. Isom
- Department of Pharmacology and
- Department of Neurology and
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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8
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Ma R, Duan Y, Zhang L, Qi X, Zhang L, Pan S, Gao L, Wang C, Wang Y. SCN1A-Related Epilepsy: Novel Mutations and Rare Phenotypes. Front Mol Neurosci 2022; 15:826183. [PMID: 35663268 PMCID: PMC9162153 DOI: 10.3389/fnmol.2022.826183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/23/2022] [Indexed: 11/13/2022] Open
Abstract
ObjectivesTo expand the genotypes and phenotypes of sodium voltage-gated channel alpha subunit 1 (SCN1A)-related epilepsy.MethodsWe retrospectively collected the clinical and genetic information of 22 epilepsy patients (10 males, 12 females; mean: 9.2 ± 3.9 years; 3.9–20.3 years) carrying 22 variants of SCN1A. SCN1A mutations were identified by next-generation sequencing.ResultsTwenty-two variants were identified, among which 12 have not yet been reported. The median age at seizure onset was 6 months. Sixteen patients were diagnosed with Dravet syndrome (DS), two with genetic epilepsy with febrile seizures plus [one evolved into benign epilepsy with centrotemporal spikes (BECTS)], one with focal epilepsy, one with atypical childhood epilepsy with centrotemporal spikes (ABECTS) and two with unclassified epilepsy. Fourteen patients showed a global developmental delay/intellectual disability (GDD/ID). Slow background activities were observed in one patient and epileptiform discharges were observed in 11 patients during the interictal phase.SignificanceThis study enriches the genotypes and phenotypes of SCN1A-related epilepsy. The clinical characteristics of patients with 12 previously unreported variants were described.
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9
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Angsutararux P, Zhu W, Voelker TL, Silva JR. Molecular Pathology of Sodium Channel Beta-Subunit Variants. Front Pharmacol 2021; 12:761275. [PMID: 34867379 PMCID: PMC8640220 DOI: 10.3389/fphar.2021.761275] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/28/2021] [Indexed: 12/19/2022] Open
Abstract
The voltage-gated Na+ channel regulates the initiation and propagation of the action potential in excitable cells. The major cardiac isoform NaV1.5, encoded by SCN5A, comprises a monomer with four homologous repeats (I-IV) that each contain a voltage sensing domain (VSD) and pore domain. In native myocytes, NaV1.5 forms a macromolecular complex with NaVβ subunits and other regulatory proteins within the myocyte membrane to maintain normal cardiac function. Disturbance of the NaV complex may manifest as deadly cardiac arrhythmias. Although SCN5A has long been identified as a gene associated with familial atrial fibrillation (AF) and Brugada Syndrome (BrS), other genetic contributors remain poorly understood. Emerging evidence suggests that mutations in the non-covalently interacting NaVβ1 and NaVβ3 are linked to both AF and BrS. Here, we investigated the molecular pathologies of 8 variants in NaVβ1 and NaVβ3. Our results reveal that NaVβ1 and NaVβ3 variants contribute to AF and BrS disease phenotypes by modulating both NaV1.5 expression and gating properties. Most AF-linked variants in the NaVβ1 subunit do not alter the gating kinetics of the sodium channel, but rather modify the channel expression. In contrast, AF-related NaVβ3 variants directly affect channel gating, altering voltage-dependent activation and the time course of recovery from inactivation via the modulation of VSD activation.
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Affiliation(s)
- Paweorn Angsutararux
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States
| | - Wandi Zhu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States.,Department of Medicine, Brigham and Women's Hospital, Boston, MA, United States
| | - Taylor L Voelker
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, United States
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10
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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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11
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Ornelas-Loredo A, Kany S, Abraham V, Alzahrani Z, Darbar FA, Sridhar A, Ahmed M, Alamar I, Menon A, Zhang M, Chen Y, Hong L, Konda S, Darbar D. Association Between Obesity-Mediated Atrial Fibrillation and Therapy With Sodium Channel Blocker Antiarrhythmic Drugs. JAMA Cardiol 2021; 5:57-64. [PMID: 31774463 DOI: 10.1001/jamacardio.2019.4513] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Importance The association between obesity, an established risk factor for atrial fibrillation (AF), and response to antiarrhythmic drugs (AADs) remains unclear. Objective To test the hypothesis that obesity differentially mediates response to AADs in patients with symptomatic AF and in mice with diet-induced obesity (DIO) and pacing induced AF. Design, Setting, and Participants An observational cohort study was conducted including 311 patients enrolled in a clinical-genetic registry. Mice fed a high-fat diet for 10 weeks were also evaluated. The study was conducted from January 1, 2018, to June 2, 2019. Main Outcomes and Measures Symptomatic response was defined as continuation of the same AAD for at least 3 months. Nonresponse was defined as discontinuation of the AAD within 3 months of initiation because of poor symptomatic control of AF necessitating alternative rhythm control therapy. Outcome measures in DIO mice were pacing-induced AF and suppression of AF after 2 weeks of treatment with flecainide acetate or sotalol hydrochloride. Results A total of 311 patients (mean [SD] age, 65 [12] years; 120 women [38.6%]) met the entry criteria and were treated with a class I or III AAD for symptomatic AF. Nonresponse to class I AADs in patients with obesity was less than in those without obesity (30% [obese] vs 6% [nonobese]; difference, 0.24; 95% CI, 0.11-0.37; P = .001). Both groups had similar symptomatic response to a potassium channel blocker AAD. On multivariate analysis, obesity, AAD class (class I vs III AAD [obese] odds ratio [OR], 4.54; 95% Wald CI, 1.84-11.20; P = .001), female vs male sex (OR, 2.31; 95% Wald CI, 1.07-4.99; P = .03), and hyperthyroidism (OR, 4.95; 95% Wald CI, 1.23-20.00; P = .02) were significant indicators of the probability of failure to respond to AADs. Pacing induced AF in 100% of DIO mice vs 30% (P < .001) in controls. Furthermore, DIO mice showed a greater reduction in AF burden when treated with sotalol compared with flecainide (85% vs 25%; P < .01). Conclusions and Relevance Results suggest that obesity differentially mediates response to AADs in patients and in mice with AF, possibly reducing the therapeutic effectiveness of sodium channel blockers. These findings may have implications for the management of AF in patients with obesity.
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Affiliation(s)
- Aylin Ornelas-Loredo
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Shinwan Kany
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Vihas Abraham
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Zain Alzahrani
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Faisal A Darbar
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Arvind Sridhar
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Maha Ahmed
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Ihab Alamar
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Ambili Menon
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Meihang Zhang
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Yining Chen
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Liang Hong
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago
| | - Sreenivas Konda
- Division of Epidemiology and Biostatistics, University of Illinois at Chicago
| | - Dawood Darbar
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago.,Department of Medicine, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois
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12
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Hayashi K, Teramoto R, Nomura A, Asano Y, Beerens M, Kurata Y, Kobayashi I, Fujino N, Furusho H, Sakata K, Onoue K, Chiang DY, Kiviniemi TO, Buys E, Sips P, Burch ML, Zhao Y, Kelly AE, Namura M, Kita Y, Tsuchiya T, Kaku B, Oe K, Takeda Y, Konno T, Inoue M, Fujita T, Kato T, Funada A, Tada H, Hodatsu A, Nakanishi C, Sakamoto Y, Tsuda T, Nagata Y, Tanaka Y, Okada H, Usuda K, Cui S, Saito Y, MacRae CA, Takashima S, Yamagishi M, Kawashiri MA, Takamura M. Impact of functional studies on exome sequence variant interpretation in early-onset cardiac conduction system diseases. Cardiovasc Res 2020; 116:2116-2130. [PMID: 31977013 DOI: 10.1093/cvr/cvaa010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 10/02/2019] [Accepted: 01/17/2020] [Indexed: 12/20/2022] Open
Abstract
AIMS The genetic cause of cardiac conduction system disease (CCSD) has not been fully elucidated. Whole-exome sequencing (WES) can detect various genetic variants; however, the identification of pathogenic variants remains a challenge. We aimed to identify pathogenic or likely pathogenic variants in CCSD patients by using WES and 2015 American College of Medical Genetics and Genomics (ACMG) standards and guidelines as well as evaluating the usefulness of functional studies for determining them. METHODS AND RESULTS We performed WES of 23 probands diagnosed with early-onset (<65 years) CCSD and analysed 117 genes linked to arrhythmogenic diseases or cardiomyopathies. We focused on rare variants (minor allele frequency < 0.1%) that were absent from population databases. Five probands had protein truncating variants in EMD and LMNA which were classified as 'pathogenic' by 2015 ACMG standards and guidelines. To evaluate the functional changes brought about by these variants, we generated a knock-out zebrafish with CRISPR-mediated insertions or deletions of the EMD or LMNA homologs in zebrafish. The mean heart rate and conduction velocities in the CRISPR/Cas9-injected embryos and F2 generation embryos with homozygous deletions were significantly decreased. Twenty-one variants of uncertain significance were identified in 11 probands. Cellular electrophysiological study and in vivo zebrafish cardiac assay showed that two variants in KCNH2 and SCN5A, four variants in SCN10A, and one variant in MYH6 damaged each gene, which resulted in the change of the clinical significance of them from 'Uncertain significance' to 'Likely pathogenic' in six probands. CONCLUSION Of 23 CCSD probands, we successfully identified pathogenic or likely pathogenic variants in 11 probands (48%). Functional analyses of a cellular electrophysiological study and in vivo zebrafish cardiac assay might be useful for determining the pathogenicity of rare variants in patients with CCSD. SCN10A may be one of the major genes responsible for CCSD.
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Affiliation(s)
- Kenshi Hayashi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Ryota Teramoto
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.,Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Akihiro Nomura
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Yoshihiro Asano
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Suita, Japan
| | - Manu Beerens
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Yasutaka Kurata
- Department of Physiology, Kanazawa Medical University, Uchinada, Japan
| | - Isao Kobayashi
- Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Kanazawa, Japan
| | - Noboru Fujino
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Hiroshi Furusho
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Kenji Sakata
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Kenji Onoue
- Cardiovascular Medicine, Nara Medical University, Kashihara, Japan
| | - David Y Chiang
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Tuomas O Kiviniemi
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Eva Buys
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Patrick Sips
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.,Center for Medical Genetics Ghent, Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Micah L Burch
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Yanbin Zhao
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Amy E Kelly
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Masanobu Namura
- Department of Cardiology, Kanazawa Cardiovascular Hospital, Kanazawa, Japan
| | - Yoshihito Kita
- Department of Internal Medicine, Wajima Municipal Hospital, Wajima, Japan
| | - Taketsugu Tsuchiya
- Trans-catheter Cardiovascular Therapeutics, Kanazawa Medical University, Uchinada, Japan
| | - Bunji Kaku
- Division of Cardiovascular Medicine, Toyama Red Cross Hospital, Toyama, Japan
| | - Kotaro Oe
- Division of Internal Medicine, Saiseikai Kanazawa Hospital, Kanazawa, Japan
| | - Yuko Takeda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Tetsuo Konno
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Masaru Inoue
- Department of Cardiology, Ishikawa Prefectural Central Hospital, Kanazawa, Japan
| | - Takashi Fujita
- Division of Cardiology, Kouseiren Takaoka Hospital, Takaoka, Japan
| | - Takeshi Kato
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Akira Funada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Hayato Tada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Akihiko Hodatsu
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Chiaki Nakanishi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | | | - Toyonobu Tsuda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Yoji Nagata
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Yoshihiro Tanaka
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Hirofumi Okada
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Keisuke Usuda
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Shihe Cui
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Yoshihiko Saito
- Cardiovascular Medicine, Nara Medical University, Kashihara, Japan
| | - Calum A MacRae
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Seiji Takashima
- Department of Medical Biochemistry, Osaka University Graduate School of Medicine, Suita, Japan
| | - Masakazu Yamagishi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan.,Osaka University of Human Sciences, Settu, Japan
| | - Masa-Aki Kawashiri
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
| | - Masayuki Takamura
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, 13-1, Takara-machi, Kanazawa, Ishikawa 920-8641, Japan
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13
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McCauley MD, Hong L, Sridhar A, Menon A, Perike S, Zhang M, da Silva IB, Yan J, Bonini MG, Ai X, Rehman J, Darbar D. Ion Channel and Structural Remodeling in Obesity-Mediated Atrial Fibrillation. Circ Arrhythm Electrophysiol 2020; 13:e008296. [PMID: 32654503 PMCID: PMC7935016 DOI: 10.1161/circep.120.008296] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND Epidemiological studies have established obesity as an independent risk factor for atrial fibrillation (AF), but the underlying pathophysiological mechanisms remain unclear. Reduced cardiac sodium channel expression is a known causal mechanism in AF. We hypothesized that obesity decreases Nav1.5 expression via enhanced oxidative stress, thus reducing INa, and enhancing susceptibility to AF. METHODS To elucidate the underlying electrophysiological mechanisms a diet-induced obese mouse model was used. Weight, blood pressure, glucose, F2-isoprostanes, NOX2 (NADPH oxidase 2), and PKC (protein kinase C) were measured in obese mice and compared with lean controls. Invasive electrophysiological, immunohistochemistry, Western blotting, and patch clamping of membrane potentials was performed to evaluate the molecular and electrophysiological phenotype of atrial myocytes. RESULTS Pacing-induced AF in 100% of diet-induced obese mice versus 25% in controls (P<0.01) with increased AF burden. Cardiac sodium channel expression, INa and atrial action potential duration were reduced and potassium channel expression (Kv1.5) and current (IKur) and F2-isoprostanes, NOX2, and PKC-α/δ expression and atrial fibrosis were significantly increased in diet-induced obese mice as compared with controls. A mitochondrial antioxidant reduced AF burden, restored INa, ICa,L, IKur, action potential duration, and reversed atrial fibrosis in diet-induced obese mice as compared with controls. CONCLUSIONS Inducible AF in obese mice is mediated, in part, by a combined effect of sodium, potassium, and calcium channel remodeling and atrial fibrosis. Mitochondrial antioxidant therapy abrogated the ion channel and structural remodeling and reversed the obesity-induced AF burden. Our findings have important implications for the management of obesity-mediated AF in patients. Graphic Abstract: A graphic abstract is available for this article.
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Affiliation(s)
- Mark D. McCauley
- Department of Medicine, Rush University Medical Center
- Jesse Brown VA Medical Center, Rush University Medical Center
| | - Liang Hong
- Department of Medicine, Rush University Medical Center
| | | | - Ambili Menon
- Department of Medicine, Rush University Medical Center
| | | | - Meihong Zhang
- Department of Medicine, Rush University Medical Center
| | | | - JiaJie Yan
- Department of Physiology and Biophysics, Rush University Medical Center
| | | | - Xun Ai
- Department of Physiology and Biophysics, Rush University Medical Center
| | - Jalees Rehman
- Department of Medicine, Rush University Medical Center
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL
| | - Dawood Darbar
- Department of Medicine, Rush University Medical Center
- Jesse Brown VA Medical Center, Rush University Medical Center
- Department of Pharmacology, University of Illinois at Chicago, Chicago, IL
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14
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Hilderink S, Devalla HD, Bosch L, Wilders R, Verkerk AO. Ultrarapid Delayed Rectifier K + Channelopathies in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes. Front Cell Dev Biol 2020; 8:536. [PMID: 32850774 PMCID: PMC7399090 DOI: 10.3389/fcell.2020.00536] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/08/2020] [Indexed: 12/12/2022] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia. About 5-15% of AF patients have a mutation in a cardiac gene, including mutations in KCNA5, encoding the Kv1.5 α-subunit of the ion channel carrying the atrial-specific ultrarapid delayed rectifier K+ current (IKur). Both loss-of-function and gain-of-function AF-related mutations in KCNA5 are known, but their effects on action potentials (APs) of human cardiomyocytes have been poorly studied. Here, we assessed the effects of wild-type and mutant IKur on APs of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). We found that atrial-like hiPSC-CMs, generated by a retinoic acid-based differentiation protocol, have APs with faster repolarization compared to ventricular-like hiPSC-CMs, resulting in shorter APs with a lower AP plateau. Native IKur, measured as current sensitive to 50 μM 4-aminopyridine, was 1.88 ± 0.49 (mean ± SEM, n = 17) and 0.26 ± 0.26 pA/pF (n = 17) in atrial- and ventricular-like hiPSC-CMs, respectively. In both atrial- and ventricular-like hiPSC-CMs, IKur blockade had minimal effects on AP parameters. Next, we used dynamic clamp to inject various amounts of a virtual IKur, with characteristics as in freshly isolated human atrial myocytes, into 11 atrial-like and 10 ventricular-like hiPSC-CMs, in which native IKur was blocked. Injection of IKur with 100% density shortened the APs, with its effect being strongest on the AP duration at 20% repolarization (APD20) of atrial-like hiPSC-CMs. At IKur densities < 100% (compared to 100%), simulating loss-of-function mutations, significant AP prolongation and raise of plateau were observed. At IKur densities > 100%, simulating gain-of-function mutations, APD20 was decreased in both atrial- and ventricular-like hiPSC-CMs, but only upon a strong increase in IKur. In ventricular-like hiPSC-CMs, lowering of the plateau resulted in AP shortening. We conclude that a decrease in IKur, mimicking loss-of-function mutations, has a stronger effect on the AP of hiPSC-CMs than an increase, mimicking gain-of-function mutations, whereas in ventricular-like hiPSC-CMs such increase results in AP shortening, causing their AP morphology to become more atrial-like. Effects of native IKur modulation on atrial-like hiPSC-CMs are less pronounced than effects of virtual IKur injection because IKur density of atrial-like hiPSC-CMs is substantially smaller than that of freshly isolated human atrial myocytes.
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Affiliation(s)
- Sarah Hilderink
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Harsha D Devalla
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Leontien Bosch
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Ronald Wilders
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Arie O Verkerk
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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15
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Sawano M. Lone Atrial Fibrillation Reconfirmed as Unfavorable Arrhythmia. J Atheroscler Thromb 2020; 28:225-226. [PMID: 32684558 PMCID: PMC8048951 DOI: 10.5551/jat.ed137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Mitsuaki Sawano
- Keio University School of Medicine, Department of Cardiology.,Tokyo Dental College Ichikawa General Hospital, Department of Cardiology
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16
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Abstract
Susceptibility to atrial fibrillation (AF) is determined by well-recognized risk factors such as diabetes mellitus or hypertension, emerging risk factors such as sleep apnea or inflammation, and increasingly well-defined genetic variants. As discussed in detail in a companion article in this series, studies in families and in large populations have identified multiple genetic loci, specific genes, and specific variants increasing susceptibility to AF. Since it is becoming increasingly inexpensive to obtain genotype data and indeed whole genome sequence data, the question then becomes to define whether using emerging new genetics knowledge can improve care for patients both before and after development of AF. Examples of improvements in care could include identifying patients at increased risk for AF (and thus deploying increased surveillance or even low-risk preventive therapies should these be available), identifying patient subsets in whom specific therapies are likely to be effective or ineffective or in whom the driving biology could motivate the development of new mechanism-based therapies or identifying an underlying susceptibility to comorbid cardiovascular disease. While current guidelines for the care of patients with AF do not recommend routine genetic testing, this rapidly increasing knowledge base suggests that testing may now or soon have a place in the management of select patients. The opportunity is to generate, validate, and deploy clinical predictors (including family history) of AF risk, to assess the utility of incorporating genomic variants into those predictors, and to identify and validate interventions such as wearable or implantable device-based monitoring ultimately to intervene in patients with AF before they present with catastrophic complications like heart failure or stroke.
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Affiliation(s)
- M. Benjamin Shoemaker
- Department of Medicine (Cardiovascular Medicine), Vanderbilt University Medical Center, Nashville, TN
| | - Rajan L. Shah
- Department of Medicine (Cardiovascular Medicine), Stanford University Medical Center, Palo Alto, CA
| | - Dan M. Roden
- Departments of Medicine (Cardiovascular Medicine and Clinical Pharmacology), Pharmacology, and Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN
| | - Marco V. Perez
- Stanford Center for Inherited Cardiovascular Diseases, Stanford University, Palo Alto, CA
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17
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18
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Platonov PG, McNitt S, Polonsky B, Rosero SZ, Zareba W. Atrial Fibrillation in Long QT Syndrome by Genotype. Circ Arrhythm Electrophysiol 2019; 12:e007213. [PMID: 31610692 DOI: 10.1161/circep.119.007213] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Long QT syndrome (LQTS) is caused by the abnormal function of ion channels, which may also affect atrial electrophysiology and be associated with the risk of atrial fibrillation (AF). However, large-scale studies of AF risk among patients with LQTS and its relation to LQTS manifestations are lacking. We aimed to assess the risk of AF and its relationship to the LQTS genotype and the long-term prognosis in patients with LQTS. METHODS Genotype-positive patients with LQTS (784 LQT1, 746 LQT2, and 233 LQT3) were compared with 2043 genotype-negative family members. Information on the occurrence of AF was based on physician-reported ECG-verified events. Multivariate Cox proportional hazards regression analyses were performed for ages 0 to 60 and after 60 years (reflecting an early and late-onset of AF) to assess the risk of incident AF by genotype and the relationship of AF to the risk of cardiac events defined as syncope, documented torsades de pointes, and aborted cardiac arrest or sudden cardiac death. RESULTS In patients followed from birth to 60 years of age, patients with LQT3 had an increased risk of AF compared with genotype-negative family members (hazard ratio=6.62; 95% CI, 2.04-21.49; P<0.001), while neither LQT1 nor LQT2 demonstrated increased AF risk. After the age of 60 years, patients with LQT2 had significantly lower risk of AF compared with genotype-negative controls (hazard ratio=0.07; 95% CI, 0.01-0.53, P=0.011). AF was a significant predictor of cardiac events in patients with LQT3 through the age of 60 (hazard ratio=5.38; 95% CI, 1.17-24.82; P=0.031). CONCLUSIONS Our data demonstrate an increased risk of early age AF in patients with LQT3 and also indicate a protective effect of the LQT2 genotype in it's association with a decreased risk of AF after the age of 60.
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Affiliation(s)
- Pyotr G Platonov
- Department of Cardiology, Clinical Sciences, Lund University, Sweden (P.G.P.).,Clinical Cardiovascular Research Center, Division of Cardiology, University of Rochester Medical Center, NY (P.G.P., S.M., B.P., S.Z.R., W.Z.)
| | - Scott McNitt
- Clinical Cardiovascular Research Center, Division of Cardiology, University of Rochester Medical Center, NY (P.G.P., S.M., B.P., S.Z.R., W.Z.)
| | - Bronislava Polonsky
- Clinical Cardiovascular Research Center, Division of Cardiology, University of Rochester Medical Center, NY (P.G.P., S.M., B.P., S.Z.R., W.Z.)
| | - Spencer Z Rosero
- Clinical Cardiovascular Research Center, Division of Cardiology, University of Rochester Medical Center, NY (P.G.P., S.M., B.P., S.Z.R., W.Z.)
| | - Wojciech Zareba
- Clinical Cardiovascular Research Center, Division of Cardiology, University of Rochester Medical Center, NY (P.G.P., S.M., B.P., S.Z.R., W.Z.)
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19
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Aronis KN, Ali RL, Liang JA, Zhou S, Trayanova NA. Understanding AF Mechanisms Through Computational Modelling and Simulations. Arrhythm Electrophysiol Rev 2019; 8:210-219. [PMID: 31463059 PMCID: PMC6702471 DOI: 10.15420/aer.2019.28.2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/17/2019] [Indexed: 12/21/2022] Open
Abstract
AF is a progressive disease of the atria, involving complex mechanisms related to its initiation, maintenance and progression. Computational modelling provides a framework for integration of experimental and clinical findings, and has emerged as an essential part of mechanistic research in AF. The authors summarise recent advancements in development of multi-scale AF models and focus on the mechanistic links between alternations in atrial structure and electrophysiology with AF. Key AF mechanisms that have been explored using atrial modelling are pulmonary vein ectopy; atrial fibrosis and fibrosis distribution; atrial wall thickness heterogeneity; atrial adipose tissue infiltration; development of repolarisation alternans; cardiac ion channel mutations; and atrial stretch with mechano-electrical feedback. They review modelling approaches that capture variability at the cohort level and provide cohort-specific mechanistic insights. The authors conclude with a summary of future perspectives, as envisioned for the contributions of atrial modelling in the mechanistic understanding of AF.
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Affiliation(s)
- Konstantinos N Aronis
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
- Division of Cardiology, Johns Hopkins HospitalBaltimore, MD, US
| | - Rheeda L Ali
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
| | - Jialiu A Liang
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
| | - Shijie Zhou
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
| | - Natalia A Trayanova
- Department of Biomedical Engineering and the Institute for Computational Medicine, Johns Hopkins UniversityBaltimore, MD, US
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20
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Dehghani-Samani A, Madreseh-Ghahfarokhi S, Dehghani-Samani A. Mutations of Voltage-Gated Ionic Channels and Risk of Severe Cardiac Arrhythmias. ACTA CARDIOLOGICA SINICA 2019; 35:99-110. [PMID: 30930557 PMCID: PMC6434417 DOI: 10.6515/acs.201903_35(2).20181028a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 10/28/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND Arrhythmias as important malfunctions of heart are known as abnormal rhythm of heart. Several causes can make arrhythmias and most of them are related to generation and/or conduction of action potential in heart. Action potential in myocytes results from the sequential opening and closing of ion channel proteins that span the plasma membrane of individual myocytes. Action potential's conduction through the heart is depended on electrical coupling between myocytes, which is mediated by gap junctions. Generation and conduction of action potentials are related to perfect action of ionic channels in heart. OBJECTIVES This novel review comprehensively addressed the ionic mechanisms of the arrhythmogenic mutations in cardiac voltage-gated ionic channels including: CACNA1C, CACNA1D, KCNA5, KCND2, KCND3, KCNE1, KCNE2, KCNE5, KCNH2, KCNJ2, KCNJ5, KCNQ1, SCN4A, SCN5A, SCN1B, SCN2B, SCN3B and SCN4B. METHODS Current study, for the first time, review and discuses about relation between cardiac arrhythmias and whole of important voltage gated ionic channels from different families, altogether and at the same time. RESULTS This review clears that mutations in voltage-gated ionic channels play important roles in generation of severe cardiac arrhythmias, and among them it is looked that mutations in voltage-gated potassium channels are more important. CONCLUSIONS Most of induced arrhythmias due to voltage-gated ionic channels mutations result in action potentials prolongation and long QT syndromes. Study on ionic channel regulators can be considered as a subject for future research.
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Affiliation(s)
- Amir Dehghani-Samani
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord
| | - Samin Madreseh-Ghahfarokhi
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad
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Han M, Zhao M, Cheng C, Huang Y, Han S, Li W, Tu X, Luo X, Yu X, Liu Y, Chen Q, Ren X, Wang QK, Ke T. Lamin A mutation impairs interaction with nucleoporin NUP155 and disrupts nucleocytoplasmic transport in atrial fibrillation. Hum Mutat 2018; 40:310-325. [PMID: 30488537 DOI: 10.1002/humu.23691] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia. Here, we show the identification and functional characterization of one AF-associated mutation p.Arg399Cys in lamin A/C. Co-immunoprecipitation and GST pull-down assays demonstrate that lamin A/C interacts with NUP155, which is a nucleoporin and causes AF when mutated. Lamin A/C mutation p.Arg399Cys impairs the interaction between lamin A/C and NUP155, and increases extractability of NUP155 from the nuclear envelope (NE). Mutation p.Arg399Cys leads to aggregation of lamin A/C in the nucleus, although it does not impair the integrity of NE upon cellular stress. Mutation p.Arg399Cys inhibits the export of HSP70 mRNA and the nuclear import of HSP70 protein. Electrophysiological studies show that mutation p.Arg399Cys decreases the peak cardiac sodium current by decreasing the cell surface expression level of cardiac sodium channel Nav 1.5, but does not affect IKr potassium current. In conclusion, our results indicate that lamin A/C mutation p.Arg399Cys weakens the interaction between nuclear lamina (lamin A/C) and the nuclear pore complex (NUP155), leading to the development of AF. The findings provide a novel molecular mechanism for the pathogenesis of AF.
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Affiliation(s)
- Meng Han
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Miao Zhao
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Chen Cheng
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Yuan Huang
- National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Hubei University of Technology, Wuhan, P. R. China
| | - Shengna Han
- Department of Pharmacology, Basic Medical College, Zhengzhou University, Zhengzhou, P. R. China
| | - Wenjuan Li
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Xin Tu
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Xuan Luo
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Xiaoling Yu
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Yinan Liu
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Qiuyun Chen
- Center for Cardiovascular Genetics, Department of Molecular Cardiology, Lerner Research Institute, Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio
- Department of Molecular Medicine, Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio
| | - Xiang Ren
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Qing Kenneth Wang
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
- Center for Cardiovascular Genetics, Department of Molecular Cardiology, Lerner Research Institute, Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, Ohio
- Department of Molecular Medicine, Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio
| | - Tie Ke
- The Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, P. R. China
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Atrial Structural Remodeling Gene Variants in Patients with Atrial Fibrillation. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4862480. [PMID: 30276209 PMCID: PMC6151856 DOI: 10.1155/2018/4862480] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/30/2018] [Accepted: 07/17/2018] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is a common arrhythmia for which the genetic studies mainly focused on the genes involved in electrical remodeling, rather than left atrial muscle remodeling. To identify rare variants involved in atrial myopathy using mutational screening, a high-throughput next-generation sequencing (NGS) workflow was developed based on a custom AmpliSeq™ panel of 55 genes potentially involved in atrial myopathy. This workflow was applied to a cohort of 94 patients with AF, 76 with atrial dilatation and 18 without. Bioinformatic analyses used NextGENe® software and in silico tools for variant interpretation. The AmpliSeq custom-made panel efficiently explored 96.58% of the targeted sequences. Based on in silico analysis, 11 potentially pathogenic missense variants were identified that were not previously associated with AF. These variants were located in genes involved in atrial tissue structural remodeling. Three patients were also carriers of potential variants in prevalent arrhythmia-causing genes, usually associated with AF. Most of the variants were found in patients with atrial dilatation (n=9, 82%). This NGS approach was a sensitive and specific method that identified 11 potentially pathogenic variants, which are likely to play roles in the predisposition to left atrial myopathy. Functional studies are needed to confirm their pathogenicity.
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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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Furst ML, Saarel EV, Hussein AA, Wazni OM, Tchou P, Kanj M, Saliba WI, Aziz PF. Medical and Interventional Outcomes in Pediatric Lone Atrial Fibrillation. JACC Clin Electrophysiol 2018; 4:638-648. [DOI: 10.1016/j.jacep.2018.02.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 12/16/2022]
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Hayashi K, Tsuda T, Nomura A, Fujino N, Nohara A, Sakata K, Konno T, Nakanishi C, Tada H, Nagata Y, Teramoto R, Tanaka Y, Kawashiri MA, Yamagishi M. Impact of B-Type Natriuretic Peptide Level on Risk Stratification of Thromboembolism and Death in Patients With Nonvalvular Atrial Fibrillation - The Hokuriku-Plus AF Registry. Circ J 2018; 82:1271-1278. [PMID: 29491320 DOI: 10.1253/circj.cj-17-1085] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND B-type natriuretic peptide (BNP) may be a predictor of stroke risk in patients with nonvalvular atrial fibrillation (NVAF); because heart failure is associated with the incidence of stroke in AF patients. However, limited data exist regarding the association between BNP at baseline and risks of thromboembolic events (TE) and death in NVAF patients. Methods and Results: We prospectively studied 1,013 NVAF patients (725 men, 72.8±9.7 years old) from the Hokuriku-plus AF Registry to determine the relationship between BNP at baseline and prognosis among Japanese NVAF patients. During the follow-up period (median, 751 days); 31 patients experienced TE and there were 81 cases of TE/all-cause death. For each endpoint we constructed receiver-operating characteristic curves that gave cutoff points of BNP for TE (170 pg/mL) and TE/all-cause death (147 pg/mL). Multivariate analysis with the Cox-proportional hazards model indicated that high BNP was significantly associated with risks of TE (hazard ratio [HR] 3.86; 95% confidence interval [CI] 1.83-8.67; P=0.0003) and TE/all-cause death (HR 2.27; 95% CI 1.45-3.56; P=0.0003). Based on the C-index and net reclassification improvement, the addition of BNP to CHA2DS2-VASc statistically improved the prediction of TE. CONCLUSIONS In a real-world cohort of Japanese NVAF patients, high BNP was significantly associated with TE and death. Plasma BNP might be a useful biomarker for these adverse clinical events.
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Affiliation(s)
- Kenshi Hayashi
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Toyonobu Tsuda
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Akihiro Nomura
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Noboru Fujino
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Atsushi Nohara
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Kenji Sakata
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Tetsuo Konno
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Chiaki Nakanishi
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Hayato Tada
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Yoji Nagata
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Ryota Teramoto
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Yoshihiro Tanaka
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Masa-Aki Kawashiri
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
| | - Masakazu Yamagishi
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medical Science
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Barichello S, Roberts JD, Backx P, Boyle PM, Laksman Z. Personalizing therapy for atrial fibrillation: the role of stem cell and in silico disease models. Cardiovasc Res 2018; 114:931-943. [DOI: 10.1093/cvr/cvy090] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 04/06/2018] [Indexed: 11/12/2022] Open
Affiliation(s)
- Scott Barichello
- University of British Columbia, 2329 West Mall, Vancouver, BC V6T 1Z4, Canada
| | - Jason D Roberts
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, ON, Canada
| | | | - Patrick M Boyle
- Department of Biomedical Engineering and Institute for Computational Medicine, Johns Hopkins University
| | - Zachary Laksman
- Division of Cardiology, University of British Columbia, 211-1033 Davie Street Vancouver, BC V6E 1M7, Canada
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Strege PR, Mazzone A, Bernard CE, Neshatian L, Gibbons SJ, Saito YA, Tester DJ, Calvert ML, Mayer EA, Chang L, Ackerman MJ, Beyder A, Farrugia G. Irritable bowel syndrome patients have SCN5A channelopathies that lead to decreased Na V1.5 current and mechanosensitivity. Am J Physiol Gastrointest Liver Physiol 2018; 314:G494-G503. [PMID: 29167113 PMCID: PMC5966747 DOI: 10.1152/ajpgi.00016.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The SCN5A-encoded voltage-gated mechanosensitive Na+ channel NaV1.5 is expressed in human gastrointestinal smooth muscle cells and interstitial cells of Cajal. NaV1.5 contributes to smooth muscle electrical slow waves and mechanical sensitivity. In predominantly Caucasian irritable bowel syndrome (IBS) patient cohorts, 2-3% of patients have SCN5A missense mutations that alter NaV1.5 function and may contribute to IBS pathophysiology. In this study we examined a racially and ethnically diverse cohort of IBS patients for SCN5A missense mutations, compared them with IBS-negative controls, and determined the resulting NaV1.5 voltage-dependent and mechanosensitive properties. All SCN5A exons were sequenced from somatic DNA of 252 Rome III IBS patients with diverse ethnic and racial backgrounds. Missense mutations were introduced into wild-type SCN5A by site-directed mutagenesis and cotransfected with green fluorescent protein into HEK-293 cells. NaV1.5 voltage-dependent and mechanosensitive functions were studied by whole cell electrophysiology with and without shear force. Five of 252 (2.0%) IBS patients had six rare SCN5A mutations that were absent in 377 IBS-negative controls. Six of six (100%) IBS-associated NaV1.5 mutations had voltage-dependent gating abnormalities [current density reduction (R225W, R433C, R986Q, and F1293S) and altered voltage dependence (R225W, R433C, R986Q, G1037V, and F1293S)], and at least one kinetic parameter was altered in all mutations. Four of six (67%) IBS-associated SCN5A mutations (R225W, R433C, R986Q, and F1293S) resulted in altered NaV1.5 mechanosensitivity. In this racially and ethnically diverse cohort of IBS patients, we show that 2% of IBS patients harbor SCN5A mutations that are absent in IBS-negative controls and result in NaV1.5 channels with abnormal voltage-dependent and mechanosensitive function. NEW & NOTEWORTHY The voltage-gated Na+ channel NaV1.5 contributes to smooth muscle physiology and electrical slow waves. In a racially and ethnically mixed irritable bowel syndrome cohort, 2% had mutations in the NaV1.5 gene SCN5A. These mutations were absent in irritable bowel syndrome-negative controls. Most mutant NaV1.5 channels were loss of function in voltage dependence or mechanosensitivity.
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Affiliation(s)
- Peter R. Strege
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Amelia Mazzone
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Cheryl E. Bernard
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Leila Neshatian
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Simon J. Gibbons
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Yuri A. Saito
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - David J. Tester
- 2Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Melissa L. Calvert
- 2Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Emeran A. Mayer
- 3Oppenheimer Center for Neurobiology of Stress and Resilience, Division of Digestive Diseases, University of California Los Angeles, Los Angeles, California
| | - Lin Chang
- 3Oppenheimer Center for Neurobiology of Stress and Resilience, Division of Digestive Diseases, University of California Los Angeles, Los Angeles, California
| | - Michael J. Ackerman
- 2Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Arthur Beyder
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Gianrico Farrugia
- 1Enteric NeuroScience Program, Division of Gastroenterology and Hepatology, Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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Teramoto R, Fujino N, Konno T, Nomura A, Nagata Y, Tsuda T, Tada H, Sakata K, Yamagishi M, Hayashi K, Kawashiri MA. Late Gadolinium Enhancement for Prediction of Mutation-Positive Hypertrophic Cardiomyopathy on the Basis of Panel-Wide Sequencing. Circ J 2018; 82:1139-1148. [PMID: 29398688 DOI: 10.1253/circj.cj-17-1012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) revealed a substantial variation in the extent of myocardial scarring, a pathological hallmark of hypertrophic cardiomyopathy (HCM). However, few data exist regarding the relationship between the presence of gene mutations and the extent of LGE. Therefore, we aimed to investigate whether variations in the extent of LGE in HCM patients can be explained by the presence or absence of disease-causing mutations.Methods and Results:We analyzed data from 82 unrelated HCM patients who underwent both LGE-CMR and next-generation sequencing. We identified disease-causing sarcomere gene mutations in 44 cases (54%). The extent of LGE on CMR was an independent factor for predicting mutation-positive HCM (odds ratio 2.12 [95% confidence interval 1.51-3.83], P<0.01). The area under the curve of %LGE was greater than that of the conventional Toronto score for predicting the presence of a mutation (0.96 vs. 0.69, P<0.01). Sensitivity, specificity, positive predictive value, and negative predictive value of %LGE (cutoff >8.1%) were 93.2%, 89.5%, 91.1%, and 91.9%, respectively. CONCLUSIONS The results demonstrated that %LGE clearly discriminated mutation-positive from mutation-negative HCM in a clinically affected HCM population. HCM with few or no myocardial scars may be genetically different from HCM with a higher incidence of myocardial scars.
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Affiliation(s)
- Ryota Teramoto
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Noboru Fujino
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Tetsuo Konno
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Akihiro Nomura
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Yoji Nagata
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Toyonobu Tsuda
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Hayato Tada
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Kenji Sakata
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Masakazu Yamagishi
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Kenshi Hayashi
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
| | - Masa-Aki Kawashiri
- Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine
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Savio-Galimberti E, Argenziano M, Antzelevitch C. Cardiac Arrhythmias Related to Sodium Channel Dysfunction. Handb Exp Pharmacol 2018; 246:331-354. [PMID: 28965168 DOI: 10.1007/164_2017_43] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The voltage-gated cardiac sodium channel (Nav1.5) is a mega-complex comprised of a pore-forming α subunit and 4 ancillary β-subunits together with numerous protein partners. Genetic defects in the form of rare variants in one or more sodium channel-related genes can cause a loss- or gain-of-function of sodium channel current (INa) leading to the manifestation of various disease phenotypes, including Brugada syndrome, long QT syndrome, progressive cardiac conduction disease, sick sinus syndrome, multifocal ectopic Purkinje-related premature contractions, and atrial fibrillation. Some sodium channelopathies have also been shown to be responsible for sudden infant death syndrome (SIDS). Although these genetic defects often present as pure electrical diseases, recent studies point to a contribution of structural abnormalities to the electrocardiographic and arrhythmic manifestation in some cases, such as dilated cardiomyopathy. The same rare variants in SCN5A or related genes may present with different clinical phenotypes in different individuals and sometimes in members of the same family. Genetic background and epigenetic and environmental factors contribute to the expression of these overlap syndromes. Our goal in this chapter is to review and discuss what is known about the clinical phenotype and genotype of each cardiac sodium channelopathy, and to briefly discuss the underlying mechanisms.
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Affiliation(s)
| | - Mariana Argenziano
- Lankenau Institute for Medical Research, 100 E. Lancaster Avenue, Wynnewood, PA, 19096, USA
| | - Charles Antzelevitch
- Lankenau Institute for Medical Research, 100 E. Lancaster Avenue, Wynnewood, PA, 19096, USA.
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Teramoto R, Tada H, Kawashiri MA, Nohara A, Nakahashi T, Konno T, Inazu A, Mabuchi H, Yamagishi M, Hayashi K. Molecular and functional characterization of familial chylomicronemia syndrome. Atherosclerosis 2017; 269:272-278. [PMID: 29153744 DOI: 10.1016/j.atherosclerosis.2017.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/01/2017] [Accepted: 11/09/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND AND AIMS Familial chylomicronemia syndrome is a rare autosomal recessive disorder leading to severe hypertriglyceridemia (HTG) due to mutations in lipoprotein lipase (LPL)-associated genes. Few data exist on the clinical features of the disorder or on comprehensive genetic approaches to uncover the causative genes and mutations. METHODS Eight patients diagnosed with familial hyperchylomicronemia with recessive inheritance were included in this study (two males and six females; median age of onset 23.0 years; mean triglyceride level 3446 mg/dl). We evaluated their clinical features, including coronary artery disease using coronary computed tomography, and performed targeted next-generation sequencing on a panel comprising 4813 genes associated with known clinical phenotypes. After standard filtering for allele frequency <1% and in silico annotation prediction, we used three types of variant filtering to identify causative mutations: homozygous mutations in known familial hyperchylomicronemia-associated genes, homozygous mutations with high damaging scores in novel genes, and deleterious mutations within 37 genes known to be associated with HTG. RESULTS A total of 1810 variants out of the 73,389 identified with 94.3% mean coverage (×20) were rare and nonsynonymous. Among these, our schema detected four pathogenic or likely pathogenic mutations in the LPL gene (p.Ala248LeufsTer4, p.Arg270Cys, p.Ala361Thr, and p.Val227Gly), including one novel mutation and a variant of uncertain significance. Patients harboring LPL gene mutations showed no severe atherosclerotic changes in the coronary arteries, but recurrent pancreatitis with long-term exposure to HTG was observed. CONCLUSIONS These results demonstrate that LPL gene plays a major role in extreme HTG associated with hyperchylomicronemia, although the condition may not cause severe atherosclerosis.
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Affiliation(s)
- Ryota Teramoto
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Hayato Tada
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan.
| | - Masa-Aki Kawashiri
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Atsushi Nohara
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Takuya Nakahashi
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Tetsuo Konno
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Akihiro Inazu
- Department of Laboratory Science, Molecular Biochemistry and Molecular Biology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
| | - Hiroshi Mabuchi
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Masakazu Yamagishi
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Kenshi Hayashi
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
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Abstract
Atrial fibrillation (AF) is a common clinical arrhythmia that appears to be highly heritable, despite representing a complex interplay of several disease processes that generally do not manifest until later in life. In this manuscript, we will review the genetic basis of this complex trait established through studies of familial AF, linkage and candidate gene studies of common AF, genome wide association studies (GWAS) of common AF, and transcriptomic studies of AF. Since AF is associated with a five-fold increase in the risk of stroke, we also review the intersection of common genetic factors associated with both of these conditions. Similarly, we highlight the intersection of common genetic markers associated with some risk factors for AF, such as hypertension and obesity, and AF. Lastly, we describe a paradigm where genetic factors predispose to the risk of AF, but which may require additional stress and trigger factors in older age to allow for the clinical manifestation of AF.
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Affiliation(s)
| | - Mina K Chung
- Department of Cardiovascular Medicine, Heart & Vascular Institute, Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave., J2-2, Cleveland, OH, 44195, USA.
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Aguilar M, Feng J, Vigmond E, Comtois P, Nattel S. Rate-Dependent Role of I Kur in Human Atrial Repolarization and Atrial Fibrillation Maintenance. Biophys J 2017; 112:1997-2010. [PMID: 28494969 DOI: 10.1016/j.bpj.2017.03.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/06/2017] [Accepted: 03/23/2017] [Indexed: 11/24/2022] Open
Abstract
The atrial-specific ultrarapid delayed rectifier K+ current (IKur) inactivates slowly but completely at depolarized voltages. The consequences for IKur rate-dependence have not been analyzed in detail and currently available mathematical action-potential (AP) models do not take into account experimentally observed IKur inactivation dynamics. Here, we developed an updated formulation of IKur inactivation that accurately reproduces time-, voltage-, and frequency-dependent inactivation. We then modified the human atrial cardiomyocyte Courtemanche AP model to incorporate realistic IKur inactivation properties. Despite markedly different inactivation dynamics, there was no difference in AP parameters across a wide range of stimulation frequencies between the original and updated models. Using the updated model, we showed that, under physiological stimulation conditions, IKur does not inactivate significantly even at high atrial rates because the transmembrane potential spends little time at voltages associated with inactivation. Thus, channel dynamics are determined principally by activation kinetics. IKur magnitude decreases at higher rates because of AP changes that reduce IKur activation. Nevertheless, the relative contribution of IKur to AP repolarization increases at higher frequencies because of reduced activation of the rapid delayed-rectifier current IKr. Consequently, IKur block produces dose-dependent termination of simulated atrial fibrillation (AF) in the absence of AF-induced electrical remodeling. The inclusion of AF-related ionic remodeling stabilizes simulated AF and greatly reduces the predicted antiarrhythmic efficacy of IKur block. Our results explain a range of experimental observations, including recently reported positive rate-dependent IKur-blocking effects on human atrial APs, and provide insights relevant to the potential value of IKur as an antiarrhythmic target for the treatment of AF.
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Affiliation(s)
- Martin Aguilar
- Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Québec, Canada; Department of Pharmacology and Physiology/Institute of Biomedical Engineering, Université de Montréal, Montreal, Québec, Canada
| | | | - Edward Vigmond
- L'Institut de Rythmologie et Modélisation Cardiaque LIRYC, Fondation Université de Bordeaux, Hôpital Xavier-Arnozan, Pessac, France; Institut de Mathématiques de Bordeaux, Université de Bordeaux, Talence, France
| | - Philippe Comtois
- Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Québec, Canada; Department of Pharmacology and Physiology/Institute of Biomedical Engineering, Université de Montréal, Montreal, Québec, Canada
| | - Stanley Nattel
- Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Québec, Canada; Department of Medicine, McGill University, Montreal, Québec, Canada; Department of Pharmacology and Therapeutics, McGill University, Montreal, Québec, Canada; Department of Medicine, Université de Montréal, Montreal, Québec, Canada; West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany.
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33
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Marczenke M, Piccini I, Mengarelli I, Fell J, Röpke A, Seebohm G, Verkerk AO, Greber B. Cardiac Subtype-Specific Modeling of K v1.5 Ion Channel Deficiency Using Human Pluripotent Stem Cells. Front Physiol 2017; 8:469. [PMID: 28729840 PMCID: PMC5498524 DOI: 10.3389/fphys.2017.00469] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 06/19/2017] [Indexed: 12/31/2022] Open
Abstract
The ultrarapid delayed rectifier K+ current (IKur), mediated by Kv1.5 channels, constitutes a key component of the atrial action potential. Functional mutations in the underlying KCNA5 gene have been shown to cause hereditary forms of atrial fibrillation (AF). Here, we combine targeted genetic engineering with cardiac subtype-specific differentiation of human induced pluripotent stem cells (hiPSCs) to explore the role of Kv1.5 in atrial hiPSC-cardiomyocytes. CRISPR/Cas9-mediated mutagenesis of integration-free hiPSCs was employed to generate a functional KCNA5 knockout. This model as well as isogenic wild-type control hiPSCs could selectively be differentiated into ventricular or atrial cardiomyocytes at high efficiency, based on the specific manipulation of retinoic acid signaling. Investigation of electrophysiological properties in Kv1.5-deficient cardiomyocytes compared to isogenic controls revealed a strictly atrial-specific disease phentoype, characterized by cardiac subtype-specific field and action potential prolongation and loss of 4-aminopyridine sensitivity. Atrial Kv1.5-deficient cardiomyocytes did not show signs of arrhythmia under adrenergic stress conditions or upon inhibiting additional types of K+ current. Exposure of bulk cultures to carbachol lowered beating frequencies and promoted chaotic spontaneous beating in a stochastic manner. Low-frequency, electrical stimulation in single cells caused atrial and mutant-specific early afterdepolarizations, linking the loss of KCNA5 function to a putative trigger mechanism in familial AF. These results clarify for the first time the role of Kv1.5 in atrial hiPSC-cardiomyocytes and demonstrate the feasibility of cardiac subtype-specific disease modeling using engineered hiPSCs.
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Affiliation(s)
- Maike Marczenke
- Human Stem Cell Pluripotency Laboratory, Max Planck Institute for Molecular BiomedicineMünster, Germany.,Chemical Genomics Centre of the Max Planck SocietyDortmund, Germany
| | - Ilaria Piccini
- Human Stem Cell Pluripotency Laboratory, Max Planck Institute for Molecular BiomedicineMünster, Germany.,Department of Cardiovascular Medicine, Institute of Genetics of Heart Diseases, University of Münster Medical SchoolMünster, Germany
| | - Isabella Mengarelli
- Department of Clinical and Experimental Cardiology, Academic Medical Center, University of AmsterdamAmsterdam, Netherlands
| | - Jakob Fell
- Human Stem Cell Pluripotency Laboratory, Max Planck Institute for Molecular BiomedicineMünster, Germany.,Chemical Genomics Centre of the Max Planck SocietyDortmund, Germany
| | - Albrecht Röpke
- Institute of Human Genetics, University of MünsterMünster, Germany
| | - Guiscard Seebohm
- Department of Cardiovascular Medicine, Institute of Genetics of Heart Diseases, University of Münster Medical SchoolMünster, Germany
| | - Arie O Verkerk
- Department of Clinical and Experimental Cardiology, Academic Medical Center, University of AmsterdamAmsterdam, Netherlands.,Department of Medical Biology, Academic Medical Center, University of AmsterdamAmsterdam, Netherlands
| | - Boris Greber
- Human Stem Cell Pluripotency Laboratory, Max Planck Institute for Molecular BiomedicineMünster, Germany.,Chemical Genomics Centre of the Max Planck SocietyDortmund, Germany
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34
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Mah DY, Shakti D, Gauvreau K, Colan SD, Alexander ME, Abrams DJ, Brown DW. Relation of Left Atrial Size to Atrial Fibrillation in Patients Aged ≤22 Years. Am J Cardiol 2017; 119:52-56. [PMID: 27780555 DOI: 10.1016/j.amjcard.2016.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/13/2016] [Accepted: 09/13/2016] [Indexed: 11/26/2022]
Abstract
Left atrial (LA) dilation has been shown to be associated with atrial fibrillation (AF) in the adult population, with some studies indicating that larger LAs are more prone to AF recurrence. The relation of LA size to AF in the pediatric and young adult population has not been investigated. In this study, all pediatric patients (aged ≤22 years) who presented to Boston Children's Hospital from January 2002 to December 2012 with AF were reviewed. Patients with significant congenital heart disease, cardiomyopathies, proven channelopathies, previous cardiac surgery, end-stage renal disease, or severe lung disease/cystic fibrosis were excluded. LA measurements were taken using the echocardiogram performed at the initial presentation. In total, 48 patients with AF were identified. The median age at presentation was 17.1 years (range 3.7 to 22.9 years); 38 patients (79%) were men. Eleven patients (23%) had at least 1 recurrence of their AF. There was no difference in body mass index, prevalence of systemic hypertension, alcohol, stimulant, or illicit drug use between those who had an isolated episode of AF and those who had a recurrence. There was no significant difference in LA dimension Z-scores between groups, with only 2 patients (1 isolated AF, 1 recurrent AF) having Z-scores >2. In conclusion, AF in the young without underlying heart disease is not associated with LA dilation.
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35
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Roberts JD, Marcus GM. Ablatogenomics: can genotype guide catheter ablation for cardiac arrhythmias? Pharmacogenomics 2016; 17:1931-1940. [PMID: 27790939 DOI: 10.2217/pgs-2016-0114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Previously confined to the management of rare inherited arrhythmia syndromes, a role for genetics within cardiac electrophysiology has begun to emerge for more common arrhythmias, including atrial fibrillation (AF). Catheter ablation for AF is an invasive procedure effective for restoring normal rhythm, however, fails in up to 40% of those undergoing their first procedure and carries a risk for serious adverse events. Recent studies have suggested that a common genetic variant within chromosome 4q25 may be a powerful predictor of procedural success, highlighting the potential of an 'ablatogenomic' strategy. Although still in its infancy, an ablatogenomic approach for AF may facilitate delivery of ablation to those most likely to benefit, while sparing those prone to fail from its risks.
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Affiliation(s)
- Jason D Roberts
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, ON N6A 4A5, Canada
| | - Gregory M Marcus
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, University of California San Francisco, San Francisco, CA 94143-1354, USA
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36
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Abstract
Despite the epidemiological scale of atrial fibrillation, current treatment strategies are of limited efficacy and safety. Ideally, novel drugs should specifically correct the pathophysiological mechanisms responsible for atrial fibrillation with no other cardiac or extracardiac actions. Atrial-selective drugs are directed toward cellular targets with sufficiently different characteristics in atria and ventricles to modify only atrial function. Several potassium (K+) channels with either predominant expression in atria or distinct electrophysiological properties in atria and ventricles can serve as atrial-selective drug targets. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting IKur, the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting IK,ACh, the Ca2+-activated K+ channels of small conductance (SK) conducting ISK, and the two pore domain K+ (K2P) channels TWIK-1, TASK-1 and TASK-3 that are responsible for voltage-independent background currents ITWIK-1, ITASK-1, and ITASK-3. Here, we briefly review the characteristics of these K+ channels and their roles in atrial fibrillation. The antiarrhythmic potential of drugs targeting the described channels is discussed as well as their putative value in treatment of atrial fibrillation.
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Affiliation(s)
- Ursula Ravens
- Institute of Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany; Department of Cardiology and Angiology I, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany; Department of Physiology, Medical Faculty Carl-Gustav-Carus, TU Dresden, Dresden, Germany.
| | - Katja E Odening
- Institute of Experimental Cardiovascular Medicine, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany; Department of Cardiology and Angiology I, University Heart Center Freiburg-Bad Krozingen, Freiburg, Germany
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37
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Clauss S, Ellinor PT. Does Atrial Fibrillation Follow Function? Ion Channel Mutations and Lone Atrial Fibrillation. Circ Arrhythm Electrophysiol 2015; 8:1005-6. [PMID: 26487618 DOI: 10.1161/circep.115.003330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Sebastian Clauss
- From the Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA (S.C., P.T.E.); Department of Medicine I, Klinikum Grosshadern, University of Munich (LMU), Munich, Germany (S.C.); DZHK (German Centre for Cardiovascular Research), Partner site Munich, Germany (S.C.); and Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA (P.T.E.)
| | - Patrick T Ellinor
- From the Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA (S.C., P.T.E.); Department of Medicine I, Klinikum Grosshadern, University of Munich (LMU), Munich, Germany (S.C.); DZHK (German Centre for Cardiovascular Research), Partner site Munich, Germany (S.C.); and Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA (P.T.E.).
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38
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Nomura A, Tada H, Teramoto R, Konno T, Hodatsu A, Won HH, Kathiresan S, Ino H, Fujino N, Yamagishi M, Hayashi K. Whole exome sequencing combined with integrated variant annotation prediction identifies a causative myosin essential light chain variant in hypertrophic cardiomyopathy. J Cardiol 2015; 67:133-9. [PMID: 26443374 DOI: 10.1016/j.jjcc.2015.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 08/19/2015] [Accepted: 09/04/2015] [Indexed: 12/30/2022]
Abstract
BACKGROUND The development of candidate gene approaches to enable molecular diagnosis of hypertrophic cardiomyopathy (HCM) has required extensive and prolonged efforts. Whole exome sequencing (WES) technologies have already accelerated genetic studies of Mendelian disorders, yielding approximately 30% diagnostic success. As a result, there is great interest in extending the use of WES to any of Mendelian diseases. This study investigated the potential of WES for molecular diagnosis of HCM. METHODS WES was performed on seven relatives from a large HCM family with a clear HCM phenotype (five clinically affected and two unaffected) in the Kanazawa University Hypertrophic Cardiomyopathy Registry. Serial bioinformatics filtering methods as well as using combined annotation dependent depletion (CADD) score and high heart expression (HHE) gene data were applied to detect the causative variant. Moreover, additional carriers of the variant were investigated in the HCM registry, and clinical characteristics harboring the variant were collected and evaluated. RESULTS WES detected 60020 rare variants in the large HCM family. Of those, 3439 were missense, nonsense, splice-site, or frameshift variants. After genotype-phenotype matching, 13 putative variants remained. Using CADD score and HHE gene data, the number of candidates was reduced to one, a variant in the myosin essential light chain (MYL3, NM_000258.2:c.281G>A, p.Arg94His) that was shared by the five affected subjects. Additional screening of the HCM registry (n=600) identified two more subjects with this variant. Serial assessments of the variant carriers revealed the following phenotypic characteristics: (1) disease-penetrance of 88%; (2) all clinically affected carriers exhibited asymmetric septal hypertrophy with a substantial maximum left ventricular wall thickness of 18±3mm without any obstruction. CONCLUSIONS WES combined with CADD score and HHE gene data may be useful even in HCM. Furthermore, the MYL3 Arg94His variant was associated with high disease penetrance and substantial interventricular septal hypertrophy.
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Affiliation(s)
- Akihiro Nomura
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan; Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Hayato Tada
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Ryota Teramoto
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Tetsuo Konno
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan; Research and Education Center for Innovative and Preventive Medicine, Kanazawa University, Kanazawa, Japan.
| | - Akihiko Hodatsu
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Hong-Hee Won
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA; Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Sekar Kathiresan
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA, USA; Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA; Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Hidekazu Ino
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Noboru Fujino
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Masakazu Yamagishi
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Kenshi Hayashi
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
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