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Ahn HJ, An HY, Ryu G, Lim J, Sun C, Song H, Choi SY, Lee H, Maurer T, Nachun D, Kwon S, Lee SR, Lip GYH, Oh S, Jaiswal S, Koh Y, Choi EK. Clonal haematopoiesis of indeterminate potential and atrial fibrillation: an east Asian cohort study. Eur Heart J 2024; 45:778-790. [PMID: 38231881 DOI: 10.1093/eurheartj/ehad869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 11/12/2023] [Accepted: 12/19/2023] [Indexed: 01/19/2024] Open
Abstract
BACKGROUND AND AIMS Both clonal haematopoiesis of indeterminate potential (CHIP) and atrial fibrillation (AF) are age-related conditions. This study investigated the potential role of CHIP in the development and progression of AF. METHODS Deep-targeted sequencing of 24 CHIP mutations (a mean depth of coverage = 1000×) was performed in 1004 patients with AF and 3341 non-AF healthy subjects. Variant allele fraction ≥ 2.0% indicated the presence of CHIP mutations. The association between CHIP and AF was evaluated by the comparison of (i) the prevalence of CHIP mutations between AF and non-AF subjects and (ii) clinical characteristics discriminated by CHIP mutations within AF patients. Furthermore, the risk of clinical outcomes-the composite of heart failure, ischaemic stroke, or death-according to the presence of CHIP mutations in AF was investigated from the UK Biobank cohort. RESULTS The mean age was 67.6 ± 6.9 vs. 58.5 ± 6.5 years in AF (paroxysmal, 39.0%; persistent, 61.0%) and non-AF cohorts, respectively. CHIP mutations with a variant allele fraction of ≥2.0% were found in 237 (23.6%) AF patients (DNMT3A, 13.5%; TET2, 6.6%; and ASXL1, 1.5%) and were more prevalent than non-AF subjects [356 (10.7%); P < .001] across the age. After multivariable adjustment (age, sex, smoking, body mass index, diabetes, and hypertension), CHIP mutations were 1.4-fold higher in AF [adjusted odds ratio (OR) 1.38; 95% confidence interval 1.10-1.74, P < .01]. The ORs of CHIP mutations were the highest in the long-standing persistent AF (adjusted OR 1.50; 95% confidence interval 1.14-1.99, P = .004) followed by persistent (adjusted OR 1.44) and paroxysmal (adjusted OR 1.33) AF. In gene-specific analyses, TET2 somatic mutation presented the highest association with AF (adjusted OR 1.65; 95% confidence interval 1.05-2.60, P = .030). AF patients with CHIP mutations were older and had a higher prevalence of diabetes, a longer AF duration, a higher E/E', and a more severely enlarged left atrium than those without CHIP mutations (all P < .05). In UK Biobank analysis of 21 286 AF subjects (1297 with CHIP and 19 989 without CHIP), the CHIP mutation in AF is associated with a 1.32-fold higher risk of a composite clinical event (heart failure, ischaemic stroke, or death). CONCLUSIONS CHIP mutations, primarily DNMT3A or TET2, are more prevalent in patients with AF than non-AF subjects whilst their presence is associated with a more progressive nature of AF and unfavourable clinical outcomes.
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Affiliation(s)
- Hyo-Jeong Ahn
- Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
| | - Hong Yul An
- Genome Opinion Incorporation, Seoul 04799, Republic of Korea
| | - Gangpyo Ryu
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Cancer Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
| | - Jiwoo Lim
- Genome Opinion Incorporation, Seoul 04799, Republic of Korea
| | - Choonghyun Sun
- Genome Opinion Incorporation, Seoul 04799, Republic of Korea
| | - Han Song
- Genome Opinion Incorporation, Seoul 04799, Republic of Korea
| | - Su-Yeon Choi
- Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
- Department of Internal Medicine, Seoul National University Hospital Healthcare System Gangnam Center, Seoul, Korea
| | - Heesun Lee
- Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
- Department of Internal Medicine, Seoul National University Hospital Healthcare System Gangnam Center, Seoul, Korea
| | - Taylor Maurer
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Daniel Nachun
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Soonil Kwon
- Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
| | - So-Ryoung Lee
- Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
- Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University, Liverpool Chest and Heart Hospital, Liverpool, UK
- Danish Center for Health Services Research, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Seil Oh
- Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
- Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
| | - Siddhartha Jaiswal
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Youngil Koh
- Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
- Genome Opinion Incorporation, Seoul 04799, Republic of Korea
- Cancer Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
- Biomedical Research Institute, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
| | - Eue-Keun Choi
- Department of Internal Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
- Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea
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2
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Curcio A, Scalise R, Indolfi C. Pathophysiology of Atrial Fibrillation and Approach to Therapy in Subjects Less than 60 Years Old. Int J Mol Sci 2024; 25:758. [PMID: 38255832 PMCID: PMC10815447 DOI: 10.3390/ijms25020758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 12/27/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
Atrial fibrillation (AF) is an arrhythmia that affects the left atrium, cardiac function, and the patients' survival rate. Due to empowered diagnostics, it has become increasingly recognized among young individuals as well, in whom it is influenced by a complex interplay of autoimmune, inflammatory, and electrophysiological mechanisms. Deepening our understanding of these mechanisms could contribute to improving AF management and treatment. Inflammation is a complexly regulated process, with interactions among various immune cell types, signaling molecules, and complement components. Addressing circulating antibodies and designing specific autoantibodies are promising therapeutic options. In cardiomyopathies or channelopathies, the first manifestation could be paroxysmal AF; persistent forms tend not to respond to antiarrhythmic drugs in these conditions. Further research, both in vitro and in vivo, on the use of genomic biotechnology could lead to new therapeutic approaches. Additional triggers that can be encountered in AF patients below 60 years of age are systemic hypertension, overweight, diabetes, and alcohol abuse. The aims of this review are to briefly report evidence from basic science and results of clinical studies that might explain the juvenile burden of the most encountered sustained supraventricular tachyarrhythmias in the general population.
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Affiliation(s)
- Antonio Curcio
- Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, 88100 Catanzaro, Italy; (R.S.); (C.I.)
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3
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Lillo MA, Muñoz M, Rhana P, Gaul-Muller K, Quan J, Shirokova N, Xie LH, Santana LF, Fraidenraich D, Contreras JE. Remodeled connexin 43 hemichannels alter cardiac excitability and promote arrhythmias. J Gen Physiol 2023; 155:e202213150. [PMID: 37191672 PMCID: PMC10192603 DOI: 10.1085/jgp.202213150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 01/25/2023] [Accepted: 04/24/2023] [Indexed: 05/17/2023] Open
Abstract
Connexin-43 (Cx43) is the most abundant protein forming gap junction channels (GJCs) in cardiac ventricles. In multiple cardiac pathologies, including hypertrophy and heart failure, Cx43 is found remodeled at the lateral side of the intercalated discs of ventricular cardiomyocytes. Remodeling of Cx43 has been long linked to spontaneous ventricular arrhythmia, yet the mechanisms by which arrhythmias develop are still debated. Using a model of dystrophic cardiomyopathy, we previously showed that remodeled Cx43 function as aberrant hemichannels (non-forming GJCs) that alter cardiomyocyte excitability and, consequently, promote arrhythmias. Here, we aim to evaluate if opening of remodeled Cx43 can serve as a general mechanism to alter cardiac excitability independent of cellular dysfunction associated with a particular cardiomyopathy. To address this issue, we used a genetically modified Cx43 knock-in mouse (S3A) that promotes cardiac remodeling of Cx43 protein without apparent cardiac dysfunction. Importantly, when S3A mice were subjected to cardiac stress using the β-adrenergic agonist isoproterenol (Iso), they displayed acute and severe arrhythmias, which were not observed in WT mice. Pretreatment of S3A mice with the Cx43 hemichannel blocker, Gap19, prevented Iso-induced abnormal electrocardiographic behavior. At the cellular level, when compared with WT, Iso-treated S3A cardiomyocytes showed increased membrane permeability, greater plasma membrane depolarization, and Ca2+ overload, which likely caused prolonged action potentials, delayed after depolarizations, and triggered activity. All these cellular dysfunctions were also prevented by Cx43 hemichannel blockers. Our results support the notion that opening of remodeled Cx43 hemichannels, regardless of the type of cardiomyopathy, is sufficient to mediate cardiac-stress-induced arrhythmogenicity.
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Affiliation(s)
- Mauricio A. Lillo
- Department of Pharmacology, Physiology and Neuroscience, Rutgers University, New Jersey Medical School, Newark, NJ, USA
| | - Manuel Muñoz
- Department of Physiology and Membrane Biology, University of California, Davis. Davis, CA, USA
| | - Paula Rhana
- Department of Physiology and Membrane Biology, University of California, Davis. Davis, CA, USA
| | - Kelli Gaul-Muller
- Department of Pharmacology, Physiology and Neuroscience, Rutgers University, New Jersey Medical School, Newark, NJ, USA
| | - Jonathan Quan
- Department of Physiology and Membrane Biology, University of California, Davis. Davis, CA, USA
| | - Natalia Shirokova
- Department of Pharmacology, Physiology and Neuroscience, Rutgers University, New Jersey Medical School, Newark, NJ, USA
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, Rutgers University, New Jersey Medical School, Newark, NJ, USA
| | - Luis Fernando Santana
- Department of Physiology and Membrane Biology, University of California, Davis. Davis, CA, USA
| | - Diego Fraidenraich
- Department of Cell Biology and Molecular Medicine, Rutgers University, New Jersey Medical School, Newark, NJ, USA
| | - Jorge E. Contreras
- Department of Pharmacology, Physiology and Neuroscience, Rutgers University, New Jersey Medical School, Newark, NJ, USA
- Department of Physiology and Membrane Biology, University of California, Davis. Davis, CA, USA
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4
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Chevalier P, Moreau A, Bessière F, Richard S, Chahine M, Millat G, Morel E, Paganelli F, Lesavre N, Placide L, Montestruc F, Ankou B, Puertas RD, Asatryan B, Delinière A. Identification of Cx43 variants predisposing to ventricular fibrillation in the acute phase of ST-elevation myocardial infarction. Europace 2023; 25:101-111. [PMID: 35942675 PMCID: PMC10103570 DOI: 10.1093/europace/euac128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 07/01/2022] [Indexed: 11/13/2022] Open
Abstract
AIMS Ventricular fibrillation (VF) occurring in the acute phase of ST-elevation myocardial infarction (STEMI) is the leading cause of sudden cardiac death worldwide. Several studies showed that reduced connexin 43 (Cx43) expression and reduced conduction velocity increase the risk of VF in acute myocardial infarction (MI). Furthermore, genetic background might predispose individuals to primary VF (PVF). The primary objective was to evaluate the presence of GJA1 variants in STEMI patients. The secondary objective was to evaluate the arrhythmogenic impact of GJA1 variants in STEMI patients with VF. METHODS AND RESULTS The MAP-IDM prospective cohort study included 966 STEMI patients and was designed to identify genetic predisposition to VF. A total of 483 (50.0%) STEMI patients with PVF were included. The presence of GJA1 variants increased the risk of VF in STEMI patients [from 49.1 to 70.8%, P = 0.0423; odds ratio (OR): 0.40; 95% confidence interval: 0.16-0.97; P = 0.04]. The risk of PVF decreased with beta-blocker intake (from 53.5 to 44.8%, P = 0.0085), atrial fibrillation (from 50.7 to 26.4%, P = 0.0022), and with left ventricular ejection fraction >50% (from 60.2 to 41.4%, P < 0.0001). Among 16 GJA1 variants, three novel heterozygous missense variants were identified in three patients: V236I, H248R, and I327M. In vitro studies of these variants showed altered Cx43 localization and decreased cellular communication, mainly during acidosis. CONCLUSION Connexin 43 variants are associated with increased VF susceptibility in STEMI patients. Restoring Cx43 function may be a potential therapeutic target to prevent PVF in patients with acute MI. CLINICAL TRIAL REGISTRATION Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT00859300.
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Affiliation(s)
- Philippe Chevalier
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | - Adrien Moreau
- PhyMedExp, INSERM U1046, CNRS UMR9214, Université de Montpellier, CHU Arnaud de Villeneuve, 34295 Montpellier, France
| | - Francis Bessière
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | - Sylvain Richard
- PhyMedExp, INSERM U1046, CNRS UMR9214, Université de Montpellier, CHU Arnaud de Villeneuve, 34295 Montpellier, France
| | | | - Gilles Millat
- Laboratoire de Cardiogénétique moléculaire, Centre de biologie et pathologie Est, Bron, France
| | - Elodie Morel
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | | | | | - Leslie Placide
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | | | - Bénédicte Ankou
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
| | - Rosa Doñate Puertas
- Signaling and Cardiovascular Pathophysiology-UMR-S 1180, Inserm, Université Paris-Saclay, Paris, France
| | - Babken Asatryan
- Department of Cardiology, Inselspital, Bern University Hospital, Bern, Switzerland
| | - Antoine Delinière
- Université de Lyon, université Lyon 1, Inserm, CNRS, INMG, Lyon F-69008, France.,Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Rythmologie, Hôpital Cardiologique Louis Pradel, 59 Boulevard Pinel, 69677 Bron Cedex, France
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5
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Towards a Better Understanding of Genotype-Phenotype Correlations and Therapeutic Targets for Cardiocutaneous Genes: The Importance of Functional Studies above Prediction. Int J Mol Sci 2022; 23:ijms231810765. [PMID: 36142674 PMCID: PMC9503274 DOI: 10.3390/ijms231810765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/17/2022] Open
Abstract
Genetic variants in gene-encoding proteins involved in cell−cell connecting structures, such as desmosomes and gap junctions, may cause a skin and/or cardiac phenotype, of which the combination is called cardiocutaneous syndrome. The cardiac phenotype is characterized by cardiomyopathy and/or arrhythmias, while the skin particularly displays phenotypes such as keratoderma, hair abnormalities and skin fragility. The reported variants associated with cardiocutaneous syndrome, in genes DSP, JUP, DSC2, KLHL24, GJA1, are classified by interpretation guidelines from the American College of Medical Genetics and Genomics. The genotype−phenotype correlation, however, remains poorly understood. By providing an overview of variants that are assessed for a functional protein pathology, we show that this number (n = 115) is low compared to the number of variants that are assessed by in silico algorithms (>5000). As expected, there is a mismatch between the prediction of variant pathogenicity and the prediction of the functional effect compared to the real functional evidence. Aiding to improve genotype−phenotype correlations, we separate variants into ‘protein reducing’ or ‘altered protein’ variants and provide general conclusions about the skin and heart phenotype involved. We conclude by stipulating that adequate prognoses can only be given, and targeted therapies can only be designed, upon full knowledge of the protein pathology through functional investigation.
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6
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Tan R, Cong T, Xu G, Hao Z, Liao J, Xie Y, Lin Y, Yang X, Li Q, Liu Y, Xia YL. Anthracycline-Induced Atrial Structural and Electrical Remodeling Characterizes Early Cardiotoxicity and Contributes to Atrial Conductive Instability and Dysfunction. Antioxid Redox Signal 2022; 37:19-39. [PMID: 35081742 DOI: 10.1089/ars.2021.0002] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aims: Cancer patients treated with anthracyclines are susceptible to atrial fibrillation (AF), while the mechanisms remain unclear. Due to sudden and unpredictable features, prediction of anthracycline-induced AF at early phase is difficult. Clinically, we tested whether anthracycline-induced early atrial remodeling in patients could be detected by echocardiography. Experimentally, we investigated the mechanisms of doxorubicin-induced atrial remodeling and AF in mice, and the protective effects of dexrazoxane and antioxidants. Methods and Results: Postsurgery breast cancer patients with an anthracycline-containing or anthracycline exclusion regimen were recruited for echocardiography before chemotherapy, and 3 and 6 months after chemotherapy. Mice were injected with doxorubicin or vehicle (5 mg/kg/week, 4 weeks), and left atrial diameter, electrical transmission, and AF inducibility were measured. Meanwhile, the level of reactive oxygen species (ROS), activity of antioxidant enzymes, cardiomyocyte size, vacuolization, inflammation, and fibrosis were also measured in mouse atria. The therapeutic effects of dexrazoxane and antioxidants on doxorubicin-induced changes in the aforementioned parameters were also determined. While ventricular parameters and functions were unchanged in cancer patients receiving anthracyclines before and after chemotherapy, left atrial reservoir and conduit function were decreased at 3 months postchemotherapy versus prechemotherapy. Doxorubicin-induced susceptibility to AF occurred in mice before onset of ventricular dysfunction. Doxorubicin-induced AF was via inducing structural remodeling (cardiomyocyte death, hypotrophy, and vacuolization) and electrical remodeling (reduction and redistribution of connexin 43) in atria, which was effectively prevented by dexrazoxane or antioxidants through inhibiting ROS generation or enhancing ROS elimination. Innovation and Conclusion: AF inducibility was induced after doxorubicin injection, which can be inhibited by repressing the ROS level. Antioxid. Redox Signal. 37, 19-39. The Clinical Trial Registration number is PJ-KS-KY-2019-73.
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Affiliation(s)
- Ruopeng Tan
- Institute of Cardiovascular Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Tao Cong
- Department of Cardiology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Guiwen Xu
- Institute of Cardiovascular Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Zhujing Hao
- Institute of Cardiovascular Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Jiawei Liao
- Institute of Cardiovascular Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Yunpeng Xie
- Institute of Cardiovascular Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Yajuan Lin
- Institute of Cardiovascular Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Xiaolei Yang
- Institute of Cardiovascular Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Qingsong Li
- Department of Cardiology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Yang Liu
- Institute of Cardiovascular Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Yun-Long Xia
- Institute of Cardiovascular Diseases, The First Affiliated Hospital of Dalian Medical University, Dalian, China.,Department of Cardiology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
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7
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Young LJ, Antwi-Boasiako S, Ferrall J, Wold LE, Mohler PJ, El Refaey M. Genetic and non-genetic risk factors associated with atrial fibrillation. Life Sci 2022; 299:120529. [PMID: 35385795 PMCID: PMC9058231 DOI: 10.1016/j.lfs.2022.120529] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/08/2022] [Accepted: 03/31/2022] [Indexed: 12/15/2022]
Abstract
Atrial fibrillation (AF) is the most common arrhythmic disorder and its prevalence in the United States is projected to increase to more than twelve million cases in 2030. AF increases the risk of other forms of cardiovascular disease, including stroke. As the incidence of atrial fibrillation increases dramatically with age, it is paramount to elucidate risk factors underlying AF pathogenesis. Here, we review tissue and cellular pathways underlying AF, as well as critical components that impact AF susceptibility including genetic and environmental risk factors. Finally, we provide the latest information on potential links between SARS-CoV-2 and human AF. Improved understanding of mechanistic pathways holds promise in preventative care and early diagnostics, and also introduces novel targeted forms of therapy that might attenuate AF progression and maintenance.
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Affiliation(s)
- Lindsay J Young
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Steve Antwi-Boasiako
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Joel Ferrall
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Loren E Wold
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA; College of Nursing, The Ohio State University, Columbus, OH, USA
| | - Peter J Mohler
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA; Department of Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH, USA
| | - Mona El Refaey
- The Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA; Department of Surgery, Division of Cardiac Surgery, The Ohio State University, Columbus, OH, USA.
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8
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Jæger KH, Edwards AG, Giles WR, Tveito A. Arrhythmogenic influence of mutations in a myocyte-based computational model of the pulmonary vein sleeve. Sci Rep 2022; 12:7040. [PMID: 35487957 PMCID: PMC9054808 DOI: 10.1038/s41598-022-11110-1] [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: 01/12/2022] [Accepted: 04/12/2022] [Indexed: 11/09/2022] Open
Abstract
In the heart, electrophysiological dysregulation arises from defects at many biological levels (from point mutations in ion channel proteins to gross structural abnormalities). These defects disrupt the normal pattern of electrical activation, producing ectopic activity and reentrant arrhythmia. To interrogate mechanisms that link these primary biological defects to macroscopic electrophysiologic dysregulation most prior computational studies have utilized either (i) detailed models of myocyte ion channel dynamics at limited spatial scales, or (ii) homogenized models of action potential conduction that reproduce arrhythmic activity at tissue and organ levels. Here we apply our recent model (EMI), which integrates electrical activation and propagation across these scales, to study human atrial arrhythmias originating in the pulmonary vein (PV) sleeves. These small structures initiate most supraventricular arrhythmias and include pronounced myocyte-to-myocyte heterogeneities in ion channel expression and intercellular coupling. To test EMI's cell-based architecture in this physiological context we asked whether ion channel mutations known to underlie atrial fibrillation are capable of initiating arrhythmogenic behavior via increased excitability or reentry in a schematic PV sleeve geometry. Our results illustrate that EMI's improved spatial resolution can directly interrogate how electrophysiological changes at the individual myocyte level manifest in tissue and as arrhythmia in the PV sleeve.
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Affiliation(s)
| | | | - Wayne R Giles
- Simula Research Laboratory, Oslo, Norway.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
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9
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Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia despite substantial efforts to understand the pathophysiology of the condition and develop improved treatments. Identifying the underlying causative mechanisms of AF in individual patients is difficult and the efficacy of current therapies is suboptimal. Consequently, the incidence of AF is steadily rising and there is a pressing need for novel therapies. Research has revealed that defects in specific molecular pathways underlie AF pathogenesis, resulting in electrical conduction disorders that drive AF. The severity of this so-called electropathology correlates with the stage of AF disease progression and determines the response to AF treatment. Therefore, unravelling the molecular mechanisms underlying electropathology is expected to fuel the development of innovative personalized diagnostic tools and mechanism-based therapies. Moreover, the co-creation of AF studies with patients to implement novel diagnostic tools and therapies is a prerequisite for successful personalized AF management. Currently, various treatment modalities targeting AF-related electropathology, including lifestyle changes, pharmaceutical and nutraceutical therapy, substrate-based ablative therapy, and neuromodulation, are available to maintain sinus rhythm and might offer a novel holistic strategy to treat AF.
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Affiliation(s)
- Bianca J J M Brundel
- Department of Physiology, Amsterdam University Medical Centers, VU Universiteit, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.
| | - Xun Ai
- Department of Physiology and Cell Biology, College of Medicine/Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | | | - Myrthe F Kuipers
- AFIPonline.org, Atrial Fibrillation Innovation Platform, Amsterdam, Netherlands
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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10
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Guo YH, Yang YQ. Atrial Fibrillation: Focus on Myocardial Connexins and Gap Junctions. BIOLOGY 2022; 11:489. [PMID: 35453689 PMCID: PMC9029470 DOI: 10.3390/biology11040489] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
Atrial fibrillation (AF) represents the most common type of clinical cardiac arrhythmia worldwide and contributes to substantial morbidity, mortality and socioeconomic burden. Aggregating evidence highlights the strong genetic basis of AF. In addition to chromosomal abnormalities, pathogenic mutations in over 50 genes have been causally linked to AF, of which the majority encode ion channels, cardiac structural proteins, transcription factors and gap junction channels. In the heart, gap junctions comprised of connexins (Cxs) form intercellular pathways responsible for electrical coupling and rapid coordinated action potential propagation between adjacent cardiomyocytes. Among the 21 isoforms of connexins already identified in the mammal genomes, 5 isoforms (Cx37, Cx40, Cx43, Cx45 and Cx46) are expressed in human heart. Abnormal electrical coupling between cardiomyocytes caused by structural remodeling of gap junction channels (alterations in connexin distribution and protein levels) has been associated with enhanced susceptibility to AF and recent studies have revealed multiple causative mutations or polymorphisms in 4 isoforms of connexins predisposing to AF. In this review, an overview of the genetics of AF is made, with a focus on the roles of mutant myocardial connexins and gap junctions in the pathogenesis of AF, to underscore the hypothesis that cardiac connexins are a major molecular target in the management of AF.
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Affiliation(s)
- Yu-Han Guo
- Department of Cardiology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China;
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China;
- Cardiovascular Research Laboratory, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China
- Center Laboratory, Shanghai Fifth People’s Hospital, Fudan University, Shanghai 200240, China
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11
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Cytoskeletal Protein Variants Driving Atrial Fibrillation: Potential Mechanisms of Action. Cells 2022; 11:cells11030416. [PMID: 35159226 PMCID: PMC8834312 DOI: 10.3390/cells11030416] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/15/2022] [Accepted: 01/20/2022] [Indexed: 11/16/2022] Open
Abstract
The most common clinical tachyarrhythmia, atrial fibrillation (AF), is present in 1-2% of the population. Although common risk factors, including hypertension, diabetes, and obesity, frequently underlie AF onset, it has been recognized that in 15% of the AF population, AF is familial. In these families, genome and exome sequencing techniques identified variants in the non-coding genome (i.e., variant regulatory elements), genes encoding ion channels, as well as genes encoding cytoskeletal (-associated) proteins. Cytoskeletal protein variants include variants in desmin, lamin A/C, titin, myosin heavy and light chain, junctophilin, nucleoporin, nesprin, and filamin C. These cytoskeletal protein variants have a strong association with the development of cardiomyopathy. Interestingly, AF onset is often represented as the initial manifestation of cardiac disease, sometimes even preceding cardiomyopathy by several years. Although emerging research findings reveal cytoskeletal protein variants to disrupt the cardiomyocyte structure and trigger DNA damage, exploration of the pathophysiological mechanisms of genetic AF is still in its infancy. In this review, we provide an overview of cytoskeletal (-associated) gene variants that relate to genetic AF and highlight potential pathophysiological pathways that drive this arrhythmia.
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12
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Abstract
Advances in population-scale genomic sequencing have greatly expanded the understanding of the inherited basis of cardiovascular disease (CVD). Reanalysis of these genomic datasets identified an unexpected risk factor for CVD, somatically acquired DNA mutations. In this review, we provide an overview of somatic mutations and their contributions to CVD. We focus on the most common and well-described manifestation, clonal hematopoiesis of indeterminate potential. We also review the currently available data regarding how somatic mutations lead to tissue mosaicism in various forms of CVD, including atrial fibrillation and aortic aneurism associated with Marfan Syndrome. Finally, we highlight future research directions given current knowledge gaps and consider how technological advances will enhance the discovery of somatic mutations in CVD and management of patients with somatic mutations.
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Affiliation(s)
- J. Brett Heimlich
- Department of Medicine, Division of Cardiovascular Medicine, Vanderbilt University Medical Center
| | - Alexander G. Bick
- Department of Medicine, Division of Genetic Medicine, Vanderbilt University Medical Center
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13
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Maleszewski JJ, Lai CK, Nair V, Veinot JP. Anatomic considerations and examination of cardiovascular specimens (excluding devices). Cardiovasc Pathol 2022. [DOI: 10.1016/b978-0-12-822224-9.00013-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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14
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Guo G, Watterson S, Zhang SD, Bjourson A, McGilligan V, Peace A, Rai TS. The role of senescence in the pathogenesis of atrial fibrillation: A target process for health improvement and drug development. Ageing Res Rev 2021; 69:101363. [PMID: 34023420 DOI: 10.1016/j.arr.2021.101363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 01/24/2021] [Accepted: 05/12/2021] [Indexed: 12/11/2022]
Abstract
Cellular senescence is a state of growth arrest that occurs after cells encounter various stresses. Senescence contributes to tumour suppression, embryonic development, and wound healing. It impacts on the pathology of various diseases by secreting inflammatory chemokines, immune modulators and other bioactive factors. These secretory biosignatures ultimately cause inflammation, tissue fibrosis, immunosenescence and many ageing-related diseases such as atrial fibrillation (AF). Because the molecular mechanisms underpinning AF development remain unclear, current treatments are suboptimal and have serious side effects. In this review, we summarize recent results describing the role of senescence in AF. We propose that senescence factors induce AF and have a causative role. Hence, targeting senescence and its secretory phenotype may attenuate AF.
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15
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Kléber AG, Jin Q. Coupling between cardiac cells-An important determinant of electrical impulse propagation and arrhythmogenesis. ACTA ACUST UNITED AC 2021; 2:031301. [PMID: 34296210 DOI: 10.1063/5.0050192] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/09/2021] [Indexed: 01/30/2023]
Abstract
Cardiac arrhythmias are an important cause of sudden cardiac death-a devastating manifestation of many underlying causes, such as heart failure and ischemic heart disease leading to ventricular tachyarrhythmias and ventricular fibrillation, and atrial fibrillation causing cerebral embolism. Cardiac electrical propagation is a main factor in the initiation and maintenance of cardiac arrhythmias. In the heart, gap junctions are the basic unit at the cellular level that host intercellular low-resistance channels for the diffusion of ions and small regulatory molecules. The dual voltage clamp technique enabled the direct measurement of electrical conductance between cells and recording of single gap junction channel openings. The rapid turnover of gap junction channels at the intercalated disk implicates a highly dynamic process of trafficking and internalization of gap junction connexons. Recently, non-canonical roles of gap junction proteins have been discovered in mitochondria function, cytoskeletal organization, trafficking, and cardiac rescue. At the tissue level, we explain the concepts of linear propagation and safety factor based on the model of linear cellular structure. Working myocardium is adequately represented as a discontinuous cellular network characterized by cellular anisotropy and connective tissue heterogeneity. Electrical propagation in discontinuous cellular networks reflects an interplay of three main factors: cell-to-cell electrical coupling, flow of electrical charge through the ion channels, and the microscopic tissue structure. This review provides a state-of-the-art update of the cardiac gap junction channels and their role in cardiac electrical impulse propagation and highlights a combined approach of genetics, cell biology, and physics in modern cardiac electrophysiology.
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Affiliation(s)
- André G Kléber
- Department of Pathology, Harvard Medical School, Boston, Massachusetts 02215, USA
| | - Qianru Jin
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, Massachusetts 02134, USA
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16
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Wu Y, Jin X, Zhang Y, Zheng J, Yang R. Genetic and epigenetic mechanisms in the development of congenital heart diseases. WORLD JOURNAL OF PEDIATRIC SURGERY 2021; 4:e000196. [DOI: 10.1136/wjps-2020-000196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 03/28/2021] [Accepted: 03/30/2021] [Indexed: 02/06/2023] Open
Abstract
Congenital heart disease (CHD) is the most common of congenital cardiovascular malformations associated with birth defects, and it results in significant morbidity and mortality worldwide. The classification of CHD is still elusive owing to the complex pathogenesis of CHD. Advances in molecular medicine have revealed the genetic basis of some heart anomalies. Genes associated with CHD might be modulated by various epigenetic factors. Thus, the genetic and epigenetic factors are gradually accepted as important triggers in the pathogenesis of CHD. However, few literatures have comprehensively elaborated the genetic and epigenetic mechanisms of CHD. This review focuses on the etiology of CHD from genetics and epigenetics to discuss the role of these factors in the development of CHD. The interactions between genetic and epigenetic in the pathogenesis of CHD are also elaborated. Chromosome abnormalities and gene mutations in genetics, and DNA methylations, histone modifications and on-coding RNAs in epigenetics are summarized in detail. We hope the summative knowledge of these etiologies may be useful for improved diagnosis and further elucidation of CHD so that morbidity and mortality of children with CHD can be reduced in the near future.
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Li RG, Xu YJ, Ye WG, Li YJ, Chen H, Qiu XB, Yang YQ, Bai D. Connexin45 (GJC1) loss-of-function mutation contributes to familial atrial fibrillation and conduction disease. Heart Rhythm 2021; 18:684-693. [PMID: 33429106 DOI: 10.1016/j.hrthm.2020.12.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) represents the most common clinical cardiac arrhythmia and substantially increases the risk of cerebral stroke, heart failure, and death. Although causative genes for AF have been identified, the genetic determinants for AF remain largely unclear. OBJECTIVE This study aimed to investigate the molecular basis of AF in a Chinese kindred. METHODS A 4-generation family with autosomal-dominant AF and other arrhythmias (atrioventricular block, sinus bradycardia, and premature ventricular contractions) was recruited. Genome-wide scan with microsatellite markers and linkage analysis as well as whole-exome sequencing analysis were performed. Electrophysiological characteristics and subcellular localization of the AF-linked mutant were analyzed using dual whole-cell patch clamps and confocal microscopy, respectively. RESULTS A novel genetic locus for AF was mapped to chromosome 17q21.3, a 3.23-cM interval between markers D17S951 and D17S931, with a maximum 2-point logarithm of odds score of 4.2144 at marker D17S1868. Sequencing analysis revealed a heterozygous mutation in the mapping region, NM_005497.4:c.703A>T;p.(M235L), in the GJC1 gene encoding connexin45 (Cx45). The mutation cosegregated with AF in the family and was absent in 632 control individuals. The mutation decreased the coupling conductance in cell pairs (M235L/M235L, M235L/Cx45, M235L/Cx43, and M235L/Cx40), likely because of impaired subcellular localization. CONCLUSION This study defines a novel genetic locus for AF on chromosome 17q21.3 and reveals a loss-of-function mutation in GJC1 (Cx45) contributing to AF and other cardiac arrhythmias.
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Affiliation(s)
- Ruo-Gu Li
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Ying-Jia Xu
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Willy G Ye
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Yan-Jie Li
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Honghong Chen
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Xing-Biao Qiu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yi-Qing Yang
- Department of Cardiology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China; Cardiovascular Research Laboratory, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China; Center Laboratory, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China.
| | - Donglin Bai
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada.
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18
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Zhang J, Johnsen SP, Guo Y, Lip GYH. Epidemiology of Atrial Fibrillation: Geographic/Ecological Risk Factors, Age, Sex, Genetics. Card Electrophysiol Clin 2021; 13:1-23. [PMID: 33516388 DOI: 10.1016/j.ccep.2020.10.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Atrial fibrillation is the most common arrhythmia globally. The global prevalence of atrial fibrillation is positively correlated with the sociodemographic index of different regions. Advancing age, male sex, and Caucasian race are risk factors; female sex is correlated with higher atrial fibrillation mortality worldwide likely owing to thromboembolic risk. African American ethnicity is associated with lower atrial fibrillation risk, same as Asian and Hispanic/Latino ethnicities compared with Caucasians. Atrial fibrillation may be heritable, and more than 100 genetic loci have been identified. A polygenic risk score and clinical risk factors are feasible and effective in risk stratification of incident disease.
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Affiliation(s)
- Juqian Zhang
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart and Chest Hospital, Liverpool, L14 3PE, UK
| | - Søren Paaske Johnsen
- Department of Clinical Medicine, Aalborg University, Søndre Skovvej 15, Aalborg, Aalborg 9000, Denmark
| | - Yutao Guo
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart and Chest Hospital, Liverpool, L14 3PE, UK; Department of Cardiology, Medical School of Chinese PLA, Chinese PLA General Hospital, Beijing, China
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart and Chest Hospital, Liverpool, L14 3PE, UK; Department of Clinical Medicine, Aalborg University, Søndre Skovvej 15, Aalborg, Aalborg 9000, Denmark; Department of Cardiology, Medical School of Chinese PLA, Chinese PLA General Hospital, Beijing, China.
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19
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Atrial fibrillation-a complex polygenetic disease. Eur J Hum Genet 2020; 29:1051-1060. [PMID: 33279945 PMCID: PMC8298566 DOI: 10.1038/s41431-020-00784-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 10/27/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common type of arrhythmia. Epidemiological studies have documented a substantial genetic component. More than 160 genes have been associated with AF during the last decades. Some of these were discovered by classical linkage studies while the majority relies on functional studies or genome-wide association studies. In this review, we will evaluate the genetic basis of AF and the role of both common and rare genetic variants in AF. Rare variants in multiple ion-channel genes as well as gap junction and transcription factor genes have been associated with AF. More recently, a growing body of evidence has implicated structural genes with AF. An increased burden of atrial fibrosis in AF patients compared with non-AF patients has also been reported. These findings challenge our traditional understanding of AF being an electrical disease. We will focus on several quantitative landmark papers, which are transforming our understanding of AF by implicating atrial cardiomyopathies in the pathogenesis. This new AF research field may enable better diagnostics and treatment in the future.
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20
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Kotadia I, Whitaker J, Roney C, Niederer S, O’Neill M, Bishop M, Wright M. Anisotropic Cardiac Conduction. Arrhythm Electrophysiol Rev 2020; 9:202-210. [PMID: 33437488 PMCID: PMC7788398 DOI: 10.15420/aer.2020.04] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 10/09/2020] [Indexed: 01/06/2023] Open
Abstract
Anisotropy is the property of directional dependence. In cardiac tissue, conduction velocity is anisotropic and its orientation is determined by myocyte direction. Cell shape and size, excitability, myocardial fibrosis, gap junction distribution and function are all considered to contribute to anisotropic conduction. In disease states, anisotropic conduction may be enhanced, and is implicated, in the genesis of pathological arrhythmias. The principal mechanism responsible for enhanced anisotropy in disease remains uncertain. Possible contributors include changes in cellular excitability, changes in gap junction distribution or function and cellular uncoupling through interstitial fibrosis. It has recently been demonstrated that myocyte orientation may be identified using diffusion tensor magnetic resonance imaging in explanted hearts, and multisite pacing protocols have been proposed to estimate myocyte orientation and anisotropic conduction in vivo. These tools have the potential to contribute to the understanding of the role of myocyte disarray and anisotropic conduction in arrhythmic states.
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Affiliation(s)
- Irum Kotadia
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - Caroline Roney
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
| | - Steven Niederer
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
| | - Mark O’Neill
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
| | - Martin Bishop
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
| | - Matthew Wright
- School of Biomedical Engineering and Imaging Sciences, King’s College, London, UK
- Guy’s and St Thomas’ NHS Foundation Trust, London, UK
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21
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Genetics and Epigenetics of Atrial Fibrillation. Int J Mol Sci 2020; 21:ijms21165717. [PMID: 32784971 PMCID: PMC7460853 DOI: 10.3390/ijms21165717] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/22/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022] Open
Abstract
Atrial fibrillation (AF) is known to be the most common supraventricular arrhythmia affecting up to 1% of the general population. Its prevalence exponentially increases with age and could reach up to 8% in the elderly population. The management of AF is a complex issue that is addressed by extensive ongoing basic and clinical research. AF centers around different types of disturbances, including ion channel dysfunction, Ca2+-handling abnormalities, and structural remodeling. Genome-wide association studies (GWAS) have uncovered over 100 genetic loci associated with AF. Most of these loci point to ion channels, distinct cardiac-enriched transcription factors, as well as to other regulatory genes. Recently, the discovery of post-transcriptional regulatory mechanisms, involving non-coding RNAs (especially microRNAs), DNA methylation, and histone modification, has allowed to decipher how a normal heart develops and which modifications are involved in reshaping the processes leading to arrhythmias. This review aims to provide a current state of the field regarding the identification and functional characterization of AF-related epigenetic regulatory networks
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22
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Ragab AAY, Sitorus GDS, Brundel BBJJM, de Groot NMS. The Genetic Puzzle of Familial Atrial Fibrillation. Front Cardiovasc Med 2020; 7:14. [PMID: 32118049 PMCID: PMC7033574 DOI: 10.3389/fcvm.2020.00014] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/28/2020] [Indexed: 12/17/2022] Open
Abstract
Atrial fibrillation (AF) is the most common clinical tachyarrhythmia. In Europe, AF is expected to reach a prevalence of 18 million by 2060. This estimate will increase hospitalization for AF to 4 million and 120 million outpatient visits. Besides being an independent risk factor for mortality, AF is also associated with an increased risk of morbidities. Although there are many well-defined risk factors for developing AF, no identifiable risk factors or cardiac pathology is seen in up to 30% of the cases. The heritability of AF has been investigated in depth since the first report of familial atrial fibrillation (FAF) in 1936. Despite the limited value of animal models, the advances in molecular genetics enabled identification of many common and rare variants related to FAF. The importance of AF heritability originates from the high prevalence of lone AF and the lack of clear understanding of the underlying pathophysiology. A better understanding of FAF will facilitate early identification of people at high risk of developing FAF and subsequent development of more effective management options. In this review, we reviewed FAF epidemiological studies, identified common and rare variants, and discussed their clinical implications and contributions to developing new personalized therapeutic strategies.
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Affiliation(s)
- Ahmed A Y Ragab
- Department of Cardiology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Gustaf D S Sitorus
- Department of Cardiology, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Bianca B J J M Brundel
- Department of Physiology, Institute for Cardiovascular Research, VU Medical Center, Amsterdam, Netherlands
| | - Natasja M S de Groot
- Department of Cardiology, Erasmus University Medical Center, Rotterdam, Netherlands
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23
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Abstract
Background Atrial fibrillation (AF) is a common arrhythmia seen in clinical practice. Occasionally, no common risk factors are present in patients with this arrhythmia. This suggests the potential underlying role of genetic factors associated with predisposition to developing AF. Methods and Results We conducted a comprehensive review of the literature through large online libraries, including PubMed. Many different potassium and sodium channel mutations have been discussed in their relation to AF. There have also been non–ion channel mutations that have been linked to AF. Genome‐wide association studies have helped in identifying potential links between single‐nucleotide polymorphisms and AF. Ancestry studies have also highlighted a role of genetics in AF. Blacks with a higher percentage of European ancestry are at higher risk of developing AF. The emerging field of ablatogenomics involves the use of genetic profiles in their relation to recurrence of AF after catheter ablation. Conclusions The evidence for the underlying role of genetics in AF continues to expand. Ultimately, the role of genetics in risk stratification of AF and its recurrence is of significant interest. No established risk scores that are useful in clinical practice are present to date.
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Affiliation(s)
- Julien Feghaly
- 1 Department of Internal Medicine St Louis University Hospital St Louis MO
| | - Patrick Zakka
- 2 Department of Internal Medicine Emory University Hospital Atlanta GA
| | - Barry London
- 3 Department of Cardiovascular Medicine University of Iowa Carver College of Medicine Iowa City IA
| | - Calum A MacRae
- 4 Department of Cardiovascular Medicine Brigham and Women's Hospital Boston MA
| | - Marwan M Refaat
- 5 Department of Cardiovascular Medicine American University of Beirut Medical Center Beirut Lebanon
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24
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Zhong Y, Tang K, Li H, Zhao D, Kou W, Xu S, Zhang J, Yang H, Li S, Guo R, Peng W, Xu Y. Rs4968309 in Myosin Light Chain 4 (MYL4) Associated With Atrial Fibrillation Onset and Predicts Clinical Outcomes After Catheter Ablation in Atrial Fibrillation Patients Without Structural Heart Disease. Circ J 2019; 83:1994-2001. [PMID: 31406021 DOI: 10.1253/circj.cj-19-0415] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia with serious complications and a high rate of recurrence after catheter ablation. Recently, mutation ofMYL4was reported as responsible for familial atrial cardiomyopathy and AF. This study aimed to determine the association between polymorphism inMYL4with the onset and recurrence of AF.Methods and Results:A total of 7 single-nucleotide polymorphisms were selected by linkage disequilibrium and genotyped in 510 consecutive AF patients and 192 controls without structural heart disease. A total of 246 AF patients who underwent cryoballoon ablation had a 1-year scheduled follow-up study for AF recurrence. C allele and CC genotype of rs4968309 and A allele of rs1515751were associated with AF onset both before and after adjustment of covariation (age, sex, hypertension, and diabetes). AF type and left atrial size were different among the genotypes of rs4968309. Moreover, CC genotype of rs4968309 increased susceptibly of AF recurrence after cryoballoon ablation. The prevalence of hypertension was associated with rs1515752, and left atrial size was associated with the genotype of rs2071438. CONCLUSIONS C allele and CC genotype of rs4968309 inMYL4were associated with AF onset and recurrence. Moreover, the A allele of rs1515751 had a significant association with AF onset. The polymorphisms ofMYL4can predict AF onset and prognosis after ablation in AF patients without structural heart disease.
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Affiliation(s)
- Yuan Zhong
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Kai Tang
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Hailing Li
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Dongdong Zhao
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Wenxin Kou
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Shaojie Xu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Jun Zhang
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Haotian Yang
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Shuang Li
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Rong Guo
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Wenhui Peng
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
| | - Yawei Xu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine
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25
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Cruz D, Pinto R, Freitas-Silva M, Nunes JP, Medeiros R. GWAS contribution to atrial fibrillation and atrial fibrillation-related stroke: pathophysiological implications. Pharmacogenomics 2019; 20:765-780. [PMID: 31368859 DOI: 10.2217/pgs-2019-0054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Atrial fibrillation (AF) and stroke are included in a group of complex traits that have been approached regarding of their study by susceptibility genetic determinants. Since 2007, several genome-wide association studies (GWAS) aiming to identify genetic variants modulating AF risk have been conducted. Thus, 11 GWAS have identified 26 SNPs (p < 5 × 10-2), of which 19 reached genome-wide significance (p < 5 × 10-8). From those variants, seven were also associated with cardioembolic stroke and three reached genome-wide significance in stroke GWAS. These associations may shed a light on putative shared etiologic mechanisms between AF and cardioembolic stroke. Additionally, some of these identified variants have been incorporated in genetic risk scores in order to elucidate new approaches of stroke prediction, prevention and treatment.
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Affiliation(s)
- Diana Cruz
- Molecular Oncology & Viral Pathology Group-Research Center, Portuguese Institute of Oncology, Edifício Laboratórios. 4° piso, Rua Dr António Bernardino de Almeida, 4200-4072 Porto, Portugal.,FMUP, Faculty of Medicine, Porto University, Alameda Prof Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Ricardo Pinto
- Molecular Oncology & Viral Pathology Group-Research Center, Portuguese Institute of Oncology, Edifício Laboratórios. 4° piso, Rua Dr António Bernardino de Almeida, 4200-4072 Porto, Portugal
| | - Margarida Freitas-Silva
- FMUP, Faculty of Medicine, Porto University, Alameda Prof Hernâni Monteiro, 4200-319 Porto, Portugal.,Department of Medicine, Centro Hospitalar São João, Porto, Portugal
| | - José Pedro Nunes
- FMUP, Faculty of Medicine, Porto University, Alameda Prof Hernâni Monteiro, 4200-319 Porto, Portugal.,Department of Medicine, Centro Hospitalar São João, Porto, Portugal
| | - Rui Medeiros
- Molecular Oncology & Viral Pathology Group-Research Center, Portuguese Institute of Oncology, Edifício Laboratórios. 4° piso, Rua Dr António Bernardino de Almeida, 4200-4072 Porto, Portugal.,FMUP, Faculty of Medicine, Porto University, Alameda Prof Hernâni Monteiro, 4200-319 Porto, Portugal.,Research Department, Portuguese League Against Cancer (NRNorte), Estrada Interior da Circunvalação, 6657, 4200-172 Porto, Portugal.,CEBIMED, Faculty of Health Sciences, Fernando Pessoa University, Praça 9 de Abril, 349, 4249-004 Porto, Portugal
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Jiang S, Guo C, Zhang W, Che W, Zhang J, Zhuang S, Wang Y, Zhang Y, Liu B. The Integrative Regulatory Network of circRNA, microRNA, and mRNA in Atrial Fibrillation. Front Genet 2019; 10:526. [PMID: 31249590 PMCID: PMC6584754 DOI: 10.3389/fgene.2019.00526] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 05/14/2019] [Indexed: 01/29/2023] Open
Abstract
Atrial fibrillation (AF) is the most common irregular heart rhythm which influence approximately 1–2% of the general population. As a potential factor for ischemic stroke, AF could also cause heart failure. The mechanisms behind AF pathogenesis is complex and remains elusive. As a new category of non-coding RNAs (ncRNAs), circular RNAs (circRNAs) have been known as the key of developmental processes, regulation of cell function, pathogenesis of heart diseases and pathological responses which could provide novel sight into the pathogenesis of AF. circRNAs function as modulators of microRNAs in cardiac disease. To investigate the regulatory mechanism of circRNA in AF, especially the complex interactions among circRNA, microRNA and mRNA, we collected the heart tissues from three AF patients and three healthy controls and profiled their circRNA expressions with circRNA Microarray. The differentially expressed circRNAs were identified and the biological functions of their interaction microRNAs and mRNAs were analyzed. Our results provided novel insights of the circRNA roles in AF and proposed highly possible interaction mechanisms among circRNAs, microRNAs, and mRNAs.
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Affiliation(s)
- Shengyang Jiang
- Department of Cardiology, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Changfa Guo
- Department of Cardiac Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Wei Zhang
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Wenliang Che
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiology, Shanghai Tenth People's Hospital Chongming Branch, Tongji University School of Medicine, Shanghai, China
| | - Jie Zhang
- Key Laboratory of Arrhythmias, Ministry of Education, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Shaowei Zhuang
- Department of Cardiology, Seventh People's Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yiting Wang
- Key Laboratory of Arrhythmias, Ministry of Education, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.,Basic Medical College, Jinzhou Medical University, Jinzhou, China
| | - Yangyang Zhang
- Key Laboratory of Arrhythmias, Ministry of Education, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.,Department of Cardiovascular Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Ban Liu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
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27
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Chorin E, Hochstadt A, Granot Y, Khoury S, Schwartz AL, Margolis G, Barashi R, Viskin D, Ghantous E, Schnapper M, Mekori T, Fourey D, Guevara-Valdivia ME, Marquez MF, Zeltzer D, Rosso R, Viskin S. Grapefruit juice prolongs the QT interval of healthy volunteers and patients with long QT syndrome. Heart Rhythm 2019; 16:1141-1148. [PMID: 31075442 DOI: 10.1016/j.hrthm.2019.04.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Indexed: 11/24/2022]
Abstract
BACKGROUND The list of medications linked to drug-induced long QT syndrome (LQTS) is diverse. It is possible that food products too have QT-prolonging potential. OBJECTIVE We tested the effects of grapefruit juice on the QT interval with the methodology used by the pharmaceutical industry to test new drugs. METHODS This was an open-label, randomized, crossover study with blinded outcome evaluation, a thorough QT study of grapefruit juice performed according to the Guidelines for the Clinical Evaluation of QT/QTc for Non-antiarrhythmic Drugs. Thirty healthy volunteers and 10 patients with congenital LQTS were studied. Healthy volunteers drank 2 L of grapefruit juice (in divided doses), or received 400 mg oral moxifloxacin, in a randomized crossover study. Patients with LQTS were tested with only grapefruit. Repeated baseline, off-drug, and on-drug (grapefruit or moxifloxacin) electrocardiograms were scanned and coded. QT measurements were done with electronic calipers. RESULTS In comparison to off-drug electrocardiograms, grapefruit juice led to significant rate-corrected QT (QTc) prolongation. The absolute net QTc prolongation from grapefruit was 14.0 ms (95% confidence interval 6.2-21.7 ms; P < .001). The QT-prolonging effects of grapefruit in healthy volunteers were comparable with those of moxifloxacin. The QT-prolonging effects of grapefruit juice were greater in female patients and particularly marked in patients with LQTS (net QTc prolongation 21.8 ms; 95% confidence interval 3.4-35.3 ms; P = .034). CONCLUSION Grapefruit juice, at doses tested, prolongs the QT interval. The effect is significant in healthy volunteers, greater in female patients, and more so in patients with LQTS.
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Affiliation(s)
- Ehud Chorin
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Aviram Hochstadt
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yoav Granot
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shafik Khoury
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Arie Lorin Schwartz
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Gilad Margolis
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Rami Barashi
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dana Viskin
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eihab Ghantous
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Michael Schnapper
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tal Mekori
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dana Fourey
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | - Manlio F Marquez
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - David Zeltzer
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Raphael Rosso
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sami Viskin
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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28
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Lozano-Velasco E, Garcia-Padilla C, Aránega AE, Franco D. Genetics of Atrial Fibrilation: In Search of Novel Therapeutic Targets. Cardiovasc Hematol Disord Drug Targets 2019; 19:183-194. [PMID: 30727926 DOI: 10.2174/1871529x19666190206150349] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 01/16/2019] [Accepted: 01/23/2019] [Indexed: 06/09/2023]
Abstract
Atrial fibrillation (AF) is the most frequent arrhythmogenic disease in humans, ranging from 2% in the general population and rising up to 10-12% in 80+ years. Genetic analyses of AF familiar cases have identified a series of point mutations in distinct ion channels, supporting a causative link. However, these genetic defects only explain a minority of AF patients. Genomewide association studies identified single nucleotide polymorphisms (SNPs), close to PITX2 on 4q25 chromosome, that are highly associated to AF. Subsequent GWAS studies have identified several new loci, involving additional transcription and growth factors. Furthermore, these risk 4q25 SNPs serve as surrogate biomarkers to identify AF recurrence in distinct surgical and pharmacological interventions. Experimental studies have demonstrated an intricate signalling pathway supporting a key role of the homeobox transcription factor PITX2 as a transcriptional regulator. Furthermore, cardiovascular risk factors such as hyperthyroidism, hypertension and redox homeostasis have been identified to modulate PITX2 driven gene regulatory networks. We provide herein a state-of-the-art review of the genetic bases of atrial fibrillation, our current understanding of the genetic regulatory networks involved in AF and its plausible usage for searching novel therapeutic targets.
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Affiliation(s)
- Estefanía Lozano-Velasco
- Cardiovascular Development Group, Department of Experimental Biology, University of Jaen, Jaen, Spain
| | - Carlos Garcia-Padilla
- Cardiovascular Development Group, Department of Experimental Biology, University of Jaen, Jaen, Spain
| | - Amelia E Aránega
- Cardiovascular Development Group, Department of Experimental Biology, University of Jaen, Jaen, Spain
| | - Diego Franco
- Cardiovascular Development Group, Department of Experimental Biology, University of Jaen, Jaen, Spain
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29
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Search of Somatic Mutations of NKX2-5 and GATA4 Genes in Chinese Patients with Sporadic Congenital Heart Disease. Pediatr Cardiol 2019; 40:17-22. [PMID: 30121862 DOI: 10.1007/s00246-018-1955-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 08/08/2018] [Indexed: 12/30/2022]
Abstract
Congenital heart disease (CHD) usually occurs sporadically, with only a minority of cases associated with a known genetic mechanism. Cardiac-specific transcription factors NKX2-5 and GATA4 play key roles in the mammalian heart development, and the affected cardiac tissues of CHD patients are prone to somatic mutations which thus participate in the pathogenesis of CHD. We collected 98 patients with sporadic CHD, extracted genomic DNA from cardiac tissues and blood, and then screened NKX2-5 and GATA4 genes using PCR-direct sequence analysis. A novel heterozygous missense mutation (c.907G > A, p.V303I) of NKX2-5 gene was identified in a patient with tetralogy of Fallots. Functional assay revealed that this mutant was associated with significantly reduced transcriptional activity. In addition, we found two known single-nucleotide polymorphisms (SNPs) (rs2277923, rs3729753) in NKX2-5 and two known SNPs (rs56166237, rs3729856) in GATA4. All variations identified in cardiac tissues were consistent with those of peripheral blood, and no somatic mutations were found in cardiac tissues. Our study shows no evidence of NKX2-5 and GATA4 somatic mutations playing a role in the pathogenesis of sporadic CHD.
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30
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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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31
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Taşdelen E, Durmaz CD, Karabulut HG. Autosomal Recessive Oculodentodigital Dysplasia: A Case Report and Review of the Literature. Cytogenet Genome Res 2018; 154:181-186. [PMID: 29902798 DOI: 10.1159/000489000] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2018] [Indexed: 11/19/2022] Open
Abstract
Oculodentodigital dysplasia (ODDD) is a rare condition characterized by a typical facial appearance and variable findings of the eyes, teeth, and fingers. ODDD is caused by mutations in the GJA1 gene in chromosome 6q22 and inherited in an autosomal dominant manner in the majority of the patients. However, in recent clinical reports, autosomal recessive ODDD cases due to by GJA1 mutations were also described. Here, we report on a 14-year-old boy with microphthalmia, microcornea, narrow nasal bridge, hypoplastic alae nasi, prominent columnella, hypodontia, dental caries, and partial syndactyly of the 2nd and 3rd toes. These clinical findings were concordant with the diagnosis of ODDD, and a novel homozygous mutation (c.442C>T, p.Arg148Ter) was determined in the GJA1 gene leading to a premature stop codon. His phenotypically normal parents were found to be carriers of the same mutation. This is the third family in the literature in which ODDD segregates in an autosomal recessive manner.
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32
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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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33
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Noureldin M, Chen H, Bai D. Functional Characterization of Novel Atrial Fibrillation-Linked GJA5 (Cx40) Mutants. Int J Mol Sci 2018; 19:E977. [PMID: 29587382 PMCID: PMC5979441 DOI: 10.3390/ijms19040977] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/16/2018] [Accepted: 03/21/2018] [Indexed: 12/18/2022] Open
Abstract
Atrial fibrillation (AF) is the most common form of cardiac arrhythmia. Recently, four novel heterozygous Cx40 mutations-K107R, L223M, Q236H, and I257L-were identified in 4 of 310 unrelated AF patients and a followup genetic analysis of the mutant carriers' families showed that the mutants were present in all the affected members. To study possible alterations associated with these Cx40 mutants, including their cellular localization and gap junction (GJ) function, we expressed GFP-tagged and untagged mutants in connexin-deficient model cells. All four Cx40 mutants showed clustered localization at cell-cell junctions similar to that observed of wildtype Cx40. However, cell pairs expressing Cx40 Q236H, but not the other individual mutants, displayed a significantly lower GJ coupling conductance (Gj) than wildtype Cx40. Similarly, co-expression of Cx40 Q236H with Cx43 resulted in a significantly lower Gj. Transjunctional voltage-dependent gating (Vj gating) properties were also altered in the GJs formed by Q236H. Reduced GJ function and altered Vj gating may play a role in promoting the Q236H carriers to AF.
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Affiliation(s)
- Mahmoud Noureldin
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, N6A 5C1 Canada.
| | - Honghong Chen
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, N6A 5C1 Canada.
| | - Donglin Bai
- Department of Physiology and Pharmacology, University of Western Ontario, London, ON, N6A 5C1 Canada.
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34
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Carballo S, Pfenniger A, Carballo D, Garin N, James RW, Mach F, Shah D, Kwak BR. Differential Association of Cx37 and Cx40 Genetic Variants in Atrial Fibrillation with and without Underlying Structural Heart Disease. Int J Mol Sci 2018; 19:E295. [PMID: 29351227 PMCID: PMC5796240 DOI: 10.3390/ijms19010295] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/12/2018] [Accepted: 01/16/2018] [Indexed: 12/17/2022] Open
Abstract
Atrial fibrillation (AF) appears in the presence or absence of structural heart disease. The majority of foci causing AF are located near the ostia of pulmonary veins (PVs), where cardiomyocytes and vascular smooth muscle cells interdigitate. Connexins (Cx) form gap junction channels and participate in action potential propagation. Genetic variants in genes encoding Cx40 and Cx37 affect their expression or function and may contribute to PV arrhythmogenicity. DNA was obtained from 196 patients with drug-resistant, symptomatic AF with and without structural heart disease, who were referred for percutaneous catheter ablation. Eighty-nine controls were matched for age, gender, hypertension, and BMI. Genotyping of the Cx40 -44G > A, Cx40 +71A > G, Cx40 -26A > G, and Cx37 1019C > T polymorphisms was performed. The promoter A Cx40 polymorphisms (-44G > A and +71A > G) showed no association with non-structural or structural AF. Distribution of the Cx40 promoter B polymorphism (-26A > G) was different in structural AF when compared to controls (p = 0.03). There was no significant difference with non-structural AF (p = 0.50). The distribution of the Cx37 1019C > T polymorphism was different in non-structural AF (p = 0.03) but not in structural AF (p = 0.08) when compared to controls. Our study describes for the first time an association of drug-resistant non-structural heart disease AF with the Cx37 1019C > T gene polymorphism. We also confirmed the association of the Cx40 - 26G > A polymorphism in patients with AF and structural disease.
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Affiliation(s)
- Sebastian Carballo
- Service of General Internal medicine, University Hospitals of Geneva, 1211 Geneva, Switzerland.
| | - Anna Pfenniger
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
| | - David Carballo
- Service of Cardiology, University Hospitals of Geneva, 1211 Geneva, Switzerland.
| | - Nicolas Garin
- Service of General Internal medicine, University Hospitals of Geneva, 1211 Geneva, Switzerland.
| | - Richard W James
- Service of Endocrinology and Diabetes, University Hospitals of Geneva, 1211 Geneva, Switzerland.
| | - François Mach
- Service of Cardiology, University Hospitals of Geneva, 1211 Geneva, Switzerland.
| | - Dipen Shah
- Service of Cardiology, University Hospitals of Geneva, 1211 Geneva, Switzerland.
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
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35
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Li N, Wang ZS, Wang XH, Xu YJ, Qiao Q, Li XM, Di RM, Guo XJ, Li RG, Zhang M, Qiu XB, Yang YQ. A SHOX2 loss-of-function mutation underlying familial atrial fibrillation. Int J Med Sci 2018; 15:1564-1572. [PMID: 30443179 PMCID: PMC6216059 DOI: 10.7150/ijms.27424] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/29/2018] [Indexed: 01/01/2023] Open
Abstract
Atrial fibrillation (AF), as the most common sustained cardiac arrhythmia, is associated with substantially increased morbidity and mortality. Aggregating evidence demonstrates that genetic defects play a crucial role in the pathogenesis of AF, especially in familial AF. Nevertheless, AF is of pronounced genetic heterogeneity, and in an overwhelming majority of cases the genetic determinants underlying AF remain elusive. In the current study, 162 unrelated patients with familial AF and 238 unrelated healthy individuals served as controls were recruited. The coding exons and splicing junction sites of the SHOX2 gene, which encodes a homeobox-containing transcription factor essential for proper development and function of the cardiac conduction system, were sequenced in all study participants. The functional effect of the mutant SHOX2 protein was characterized with a dual-luciferase reporter assay system. As a result, a novel heterozygous SHOX2 mutation, c.580C>T or p.R194X, was identified in an index patient, which was absent from the 476 control chromosomes. Genetic analysis of the proband's pedigree revealed that the nonsense mutation co-segregated with AF in the family with complete penetrance. Functional assays demonstrated that the mutant SHOX2 protein had no transcriptional activity compared with its wild-type counterpart. In conclusion, this is the first report on the association of SHOX2 loss-of-function mutation with enhanced susceptibility to familial AF, which provides novel insight into the molecular mechanism underpinning AF, suggesting potential implications for genetic counseling and individualized management of AF patients.
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Affiliation(s)
- Ning Li
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China
| | - Zhang-Sheng Wang
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China
| | - Xin-Hua Wang
- Department of Cardiology, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, 1630 Dongfang Road, Shanghai 200127, China
| | - Ying-Jia Xu
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China
| | - Qi Qiao
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China
| | - Xiu-Mei Li
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China
| | - Ruo-Min Di
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China
| | - Xiao-Juan Guo
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China.,Department of Cardiovascular Research Laboratory, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China
| | - Ruo-Gu Li
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China
| | - Min Zhang
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China
| | - Xing-Biao Qiu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiao Tong University, 241 West Huaihai Road, Shanghai 200030, China
| | - Yi-Qing Yang
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China.,Department of Cardiovascular Research Laboratory, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China.,Department of Central Laboratory, The Fifth People's Hospital of Shanghai, Fudan University, 801 Heqing Road, Shanghai 200240, China
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36
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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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37
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McCauley M, Darbar D. Germline versus somatic mutations in genetic atrial fibrillation. Heart Rhythm 2017; 14:1539-1540. [PMID: 28734984 PMCID: PMC5705188 DOI: 10.1016/j.hrthm.2017.07.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Indexed: 11/25/2022]
Affiliation(s)
- Mark McCauley
- Division of Cardiology, University of Illinois at Chicago, Chicago, Illinois
| | - Dawood Darbar
- Division of Cardiology, University of Illinois at Chicago, Chicago, Illinois.
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38
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Leybaert L, Lampe PD, Dhein S, Kwak BR, Ferdinandy P, Beyer EC, Laird DW, Naus CC, Green CR, Schulz R. Connexins in Cardiovascular and Neurovascular Health and Disease: Pharmacological Implications. Pharmacol Rev 2017; 69:396-478. [PMID: 28931622 PMCID: PMC5612248 DOI: 10.1124/pr.115.012062] [Citation(s) in RCA: 164] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Connexins are ubiquitous channel forming proteins that assemble as plasma membrane hemichannels and as intercellular gap junction channels that directly connect cells. In the heart, gap junction channels electrically connect myocytes and specialized conductive tissues to coordinate the atrial and ventricular contraction/relaxation cycles and pump function. In blood vessels, these channels facilitate long-distance endothelial cell communication, synchronize smooth muscle cell contraction, and support endothelial-smooth muscle cell communication. In the central nervous system they form cellular syncytia and coordinate neural function. Gap junction channels are normally open and hemichannels are normally closed, but pathologic conditions may restrict gap junction communication and promote hemichannel opening, thereby disturbing a delicate cellular communication balance. Until recently, most connexin-targeting agents exhibited little specificity and several off-target effects. Recent work with peptide-based approaches has demonstrated improved specificity and opened avenues for a more rational approach toward independently modulating the function of gap junctions and hemichannels. We here review the role of connexins and their channels in cardiovascular and neurovascular health and disease, focusing on crucial regulatory aspects and identification of potential targets to modify their function. We conclude that peptide-based investigations have raised several new opportunities for interfering with connexins and their channels that may soon allow preservation of gap junction communication, inhibition of hemichannel opening, and mitigation of inflammatory signaling.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Paul D Lampe
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Stefan Dhein
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Brenda R Kwak
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Peter Ferdinandy
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Eric C Beyer
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Dale W Laird
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Christian C Naus
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Colin R Green
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Rainer Schulz
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
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39
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Kucera JP, Rohr S, Kleber AG. Microstructure, Cell-to-Cell Coupling, and Ion Currents as Determinants of Electrical Propagation and Arrhythmogenesis. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.117.004665. [DOI: 10.1161/circep.117.004665] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 07/17/2017] [Indexed: 11/16/2022]
Affiliation(s)
- Jan P. Kucera
- From the Department of Physiology, University of Bern, Switzerland (J.P.K., S.R.); and the Department of Pathology, Harvard Medical School, Boston, MA (A.G.K.)
| | - Stephan Rohr
- From the Department of Physiology, University of Bern, Switzerland (J.P.K., S.R.); and the Department of Pathology, Harvard Medical School, Boston, MA (A.G.K.)
| | - Andre G. Kleber
- From the Department of Physiology, University of Bern, Switzerland (J.P.K., S.R.); and the Department of Pathology, Harvard Medical School, Boston, MA (A.G.K.)
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40
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Epifantseva I, Shaw RM. Intracellular trafficking pathways of Cx43 gap junction channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:40-47. [PMID: 28576298 DOI: 10.1016/j.bbamem.2017.05.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 05/19/2017] [Accepted: 05/25/2017] [Indexed: 12/11/2022]
Abstract
Gap Junction (GJ) channels, including the most common Connexin 43 (Cx43), have fundamental roles in excitable tissues by facilitating rapid transmission of action potentials between adjacent cells. For instance, synchronization during each heartbeat is regulated by these ion channels at the cardiomyocyte cell-cell border. Cx43 protein has a short half-life, and rapid synthesis and timely delivery of those proteins to particular subdomains are crucial for the cellular organization of gap junctions and maintenance of intracellular coupling. Impairment in gap junction trafficking contributes to dangerous complications in diseased hearts such as the arrhythmias of sudden cardiac death. Of recent interest are the protein-protein interactions with the Cx43 carboxy-terminus. These interactions have significant impact on the full length Cx43 lifecycle and also contribute to trafficking of Cx43 as well as possibly other functions. We are learning that many of the known non-canonical roles of Cx43 can be attributed to the recently identified six endogenous Cx43 truncated isoforms which are produced by internal translation. In general, alternative translation is a new leading edge for proteome expansion and therapeutic drug development. This review highlights recent mechanisms identified in the trafficking of gap junction channels, involvement of other proteins contributing to the delivery of channels to the cell-cell border, and understanding of possible roles of the newly discovered alternatively translated isoforms in Cx43 biology. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Irina Epifantseva
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Robin M Shaw
- Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA.; Department of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA..
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41
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Zhong G, Akoum N, Appadurai DA, Hayrapetyan V, Ahmed O, Martinez AD, Beyer EC, Moreno AP. Mono-Heteromeric Configurations of Gap Junction Channels Formed by Connexin43 and Connexin45 Reduce Unitary Conductance and Determine both Voltage Gating and Metabolic Flux Asymmetry. Front Physiol 2017; 8:346. [PMID: 28611680 PMCID: PMC5447054 DOI: 10.3389/fphys.2017.00346] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/11/2017] [Indexed: 11/29/2022] Open
Abstract
In cardiac tissues, the expression of multiple connexins (Cx40, Cx43, Cx45, and Cx30.2) is a requirement for proper development and function. Gap junctions formed by these connexins have distinct permeability and gating mechanisms. Since a single cell can express more than one connexin isoform, the formation of hetero-multimeric gap junction channels provides a tissue with an enormous repertoire of combinations to modulate intercellular communication. To study further the perm-selectivity and gating properties of channels containing Cx43 and Cx45, we studied two monoheteromeric combinations in which a HeLa cell co-transfected with Cx43 and Cx45 was paired with a cell expressing only one of these connexins. Macroscopic measurements of total conductance between cell pairs indicated a drastic reduction in total conductance for mono-heteromeric channels. In terms of Vj dependent gating, Cx43 homomeric connexons facing heteromeric connexons only responded weakly to voltage negativity. Cx45 homomeric connexons exhibited no change in Vj gating when facing heteromeric connexons. The distributions of unitary conductances (γj) for both mono-heteromeric channels were smaller than predicted, and both showed low permeability to the fluorescent dyes Lucifer yellow and Rhodamine123. For both mono-heteromeric channels, we observed flux asymmetry regardless of dye charge: flux was higher in the direction of the heteromeric connexon for MhetCx45 and in the direction of the homomeric Cx43 connexon for MhetCx43. Thus, our data suggest that co-expression of Cx45 and Cx43 induces the formation of heteromeric connexons with greatly reduced permeability and unitary conductance. Furthermore, it increases the asymmetry for voltage gating for opposing connexons, and it favors asymmetric flux of molecules across the junction that depends primarily on the size (not the charge) of the crossing molecules.
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Affiliation(s)
- Guoqiang Zhong
- Department of Cardiology, First Affiliated Hospital of Guangxi Medical UniversityGuangxi, China
| | - Nazem Akoum
- University Medical Center, University of WashingtonSeattle, WA, United States
| | | | | | - Osman Ahmed
- Atlanta Heart SpecialistsAtlanta, GA, United States
| | - Agustin D Martinez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de ValparaísoValparaíso, Chile
| | - Eric C Beyer
- Department of Pediatrics, University of ChicagoChicago, IL, United States
| | - Alonso P Moreno
- Cardiovascular Research and Training Institute (CVRTI), Department of Bioengineering, University of UtahSalt Lake Citiy, UT, United States
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42
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Gregers E, Ahlberg G, Christensen T, Jabbari J, Larsen KO, Herfelt CB, Henningsen KM, Andreasen L, Thiis JJ, Lund J, Holme S, Haunsø S, Bentzen BH, Schmitt N, Svendsen JH, Olesen MS. Deep sequencing of atrial fibrillation patients with mitral valve regurgitation shows no evidence of mosaicism but reveals novel rare germline variants. Heart Rhythm 2017; 14:1531-1538. [PMID: 28549997 DOI: 10.1016/j.hrthm.2017.05.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common cardiac arrhythmia. Valvular heart disease is a strong predictor, yet the underlying molecular mechanisms are unknown. OBJECTIVE The purpose of this study was to investigate the prevalence of somatic variants in AF candidate genes in an AF patient population undergoing surgery for mitral valve regurgitation (MVR) to determine whether these patients are genetically predisposed to AF. METHODS DNA was extracted from blood and left atrial tissue from 44 AF patients with MVR. Using next-generation sequencing, we investigated 110 genes using the HaloPlex Target Enrichment System. MuTect software was used for identification of somatic point variants. We functionally characterized selected variants using electrophysiologic techniques. RESULTS No somatic variants were identified in the cardiac tissue. Thirty-three patients (75%) had a rare germline variation in ≥1 candidate genes. Fourteen variants were novel. Fifteen variants were predicted damaging or likely damaging in ≥6 in silico predictions. We identified rare variants in genes never directly associated with AF: KCNE4, SCN4B, NEURL1, and CAND2. Interestingly, 7 patients (16%) had variants in genes involved in cellular potassium handling. The variants KCNQ1 (p.G272S) and KCNH2 (p.A913V) resulted in gain of function due to faster activation (KCNQ1) and slowed deactivation kinetics (KCNQ1, KCNH2). CONCLUSION We did not find any somatic variants in patients with AF and MVR. Surprisingly, we found that our cohort of non-lone AF patients might, like lone AF patients, be predisposed to AF by rare germline variants. Our findings emphasize the extent of still unknown factors in the pathogenesis of AF.
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Affiliation(s)
- Emilie Gregers
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Laboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Gustav Ahlberg
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Laboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thea Christensen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Science, University of Copenhagen, Copenhagen, Denmark
| | - Javad Jabbari
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Laboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kirstine O Larsen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Science, University of Copenhagen, Copenhagen, Denmark
| | - Cecilie B Herfelt
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Laboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristoffer M Henningsen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Laboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Laura Andreasen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Laboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Thiis
- Department of Cardiothoracic Surgery, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jens Lund
- Department of Cardiothoracic Surgery, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Susanne Holme
- Department of Cardiothoracic Surgery, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Stig Haunsø
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Laboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bo H Bentzen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Science, University of Copenhagen, Copenhagen, Denmark
| | - Nicole Schmitt
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Science, University of Copenhagen, Copenhagen, Denmark
| | - Jesper H Svendsen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Laboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Morten S Olesen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark; Laboratory for Molecular Cardiology, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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43
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Abstract
Objective: Atrial fibrillation (AF) is the most common rapid cardiac arrhythmia associated with high morbidity and mortality. Stimulation of the sympathetic nerve is involved in AF occurrence. The gap junction protein connexin 43 (Cx43) plays a key role in electrical conduction velocity in cardiac tissues, and under expression of Cx43 was linked with AF. The aim of this study was to investigate whether Cx43 was involved in sympathetic AF. Methods: Fifteen dogs were randomly divided into 3 groups (5 in each group). Sympathetic AF was induced in dogs and isolated canine atrial myocytes by isoproterenol (ISO) perfusion and rapid atrium pacing (RAP). The expression levels of nerve growth factor (NGF) and tyrosine hydroxylase (TH) in the atrial tissues were detected using immunohistochemical staining. The transcription and protein expression of Cx43 in the AF cell model was measured. Subsequently, Cx43 was blocked by short interfering (si) RNA in atrial myocytes and the gap junctional inter-cellular communication was detected using the scrape-loading and dye transfer assay. Results: Sympathetic AF was successfully induced by a combination of ISO perfusion and RAP. The expression levels of NGF and TH were increased in the RAP group, and further increased in the RAP + ISO group. Tissue samples from the AF dogs had a lower Cx43 level than those of the control group (p<0.05). The expressions of mRNA and protein of Cx43 in sympathetic AF cell model decreased by 26% and 28%, respectively, when compared with the control group, with p<0.05. Silencing Cx43 in cells by siRNA could also efficiently reduce Cx43 expression. The relative levels of Cx45 mRNA were decreased by 73% compared with unaffected cells. The scrape-loading and dye transfer assay showed that gap junctional intercellular communication was hampered in the sympathetic AF cell model and silencing Cx43 could impede channel conduction. Conclusion: The results suggested that low expression of Cx43 was involved in sympathetic AF by influencing intercellular channel conduction. Intervention of Cx43 expression might be an appealing therapy to sympathetic AF.
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44
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Gundlund A, Olesen JB, Peterson ED, Gislason GH, Fosbøl EL. Familial clustering of atrial fibrillation and comparative longitudinal outcomes of familial and non-familial atrial fibrillation. J Comp Eff Res 2017; 6:257-263. [PMID: 28485191 DOI: 10.2217/cer-2016-0088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Several studies have suggested that family history of atrial fibrillation (AF) is an important risk factor for AF, with several specific genetic regions now implicated through Genome Wide Association Studies. In addition, familial AF is associated with earlier age of onset and affects patients with fewer comorbid conditions than their non-familial counterparts. While those with familial AF have worse symptoms, all-cause mortality and risk of thromboembolic complications are similar among familial and non-familial AF patients.
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Affiliation(s)
- Anna Gundlund
- Department of Cardiology, Copenhagen University Hospital Herlev-Gentofte, Hellerup, Denmark
| | - Jonas B Olesen
- Department of Cardiology, Copenhagen University Hospital Herlev-Gentofte, Hellerup, Denmark
| | | | - Gunnar H Gislason
- Department of Cardiology, Copenhagen University Hospital Herlev-Gentofte, Hellerup, Denmark
- The National Institute of Public Health, University of Southern Denmark, Denmark
- The Danish Heart Foundation, Copenhagen, Denmark
| | - Emil L Fosbøl
- The Danish Heart Foundation, Copenhagen, Denmark
- Department of Cardiology, University Hospital of Copenhagen, Rigshospitalet, Denmark
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45
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Chen YY, Sun ZW, Jiang JP, Kang XD, Wang LL, Shen YL, Xie XD, Zheng LR. α-adrenoceptor-mediated enhanced inducibility of atrial fibrillation in a canine system inflammation model. Mol Med Rep 2017; 15:3767-3774. [PMID: 28440455 DOI: 10.3892/mmr.2017.6477] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 02/23/2017] [Indexed: 11/06/2022] Open
Abstract
The exact mechanism associated with inflammation and atrial fibrillation (AF) remains unknown. The aim of the present study was to investigate the roles of connexin 43 (Cx43) and a1‑adrenergic receptor (α1‑AR) activation in the pathogenesis of system inflammation‑induced AF. A canine model of chronic low‑grade system inflammation was established by administrating a low dose of lipopolysaccharide (LPS; 0.1 µg/kg) for 2 weeks. Programmed stimulation was applied on the right atrial appendage to determine the effective refractory periods (ERP) and the window of vulnerability (WOV). Tumor necrosis factor α (TNF‑α) and interleukin 6 (IL‑6) levels in plasma and atrial tissue were measured by ELISA. Cx43, Toll‑like receptor 4 (TLR4) and nuclear factor κB (NF‑κB) proteins were analyzed using western blotting or immunohistochemistry. Administration of LPS for 2 weeks increased the concentration of TNF‑α and IL‑6 in the plasma and right atrium. ERP was markedly shortened and cumulative WOV was significantly widened in the LPS group. Following treatment with LPS, the amount of Cx43 protein in the area of intercalated disk increased. In addition, a high‑density of Cx43 in the lateral connection was identified. LPS also induced the activation of NF‑κB in the canine atrium. Administration with the α1‑AR blocker doxazosin prevented the production of LPS‑induced inflammatory cytokine and reversed the enhanced vulnerability to atrial fibrillation. Doxazosin inhibited the LPS‑induced increase in Cx43 protein and heterogeneous distribution, and prevented the activation of NF‑κB. These results indicated that chronic low‑grade system inflammation may increase the inducibility of AF in a canine model. The underlying mechanism may be involved in the LPS‑induced activation of NF‑κB, and the increase in Cx43 expression and lateral distribution via an α1-AR-dependent pathway.
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Affiliation(s)
- Ying-Ying Chen
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Ze-Wei Sun
- Department of Cardiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
| | - Jian-Ping Jiang
- Department of Clinical Medicine, Zhejiang Medical College, Hangzhou, Zhejiang 310053, P.R. China
| | - Xiao-Dong Kang
- Experimental Animal Center, Hangzhou Normal University, Hangzhou, Zhejiang 311121, P.R. China
| | - Lin-Lin Wang
- Center for Stem Cell and Tissue Engineering, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Yue-Liang Shen
- Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, P.R. China
| | - Xu-Dong Xie
- Department of Cardiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
| | - Liang-Rong Zheng
- Department of Cardiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, P.R. China
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Atrial structure, function and arrhythmogenesis in aged and frail mice. Sci Rep 2017; 7:44336. [PMID: 28290548 PMCID: PMC5349540 DOI: 10.1038/srep44336] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/07/2017] [Indexed: 01/01/2023] Open
Abstract
Atrial fibrillation (AF) is prevalent in aging populations; however not all individuals age at the same rate. Instead, individuals of the same chronological age can vary in health status from fit to frail. Our objective was to determine the impacts of age and frailty on atrial function and arrhythmogenesis in mice using a frailty index (FI). Aged mice were more frail and demonstrated longer lasting AF compared to young mice. Consistent with this, aged mice showed longer P wave duration and PR intervals; however, both parameters showed substantial variability suggesting differences in health status among mice of similar chronological age. In agreement with this, P wave duration and PR interval were highly correlated with FI score. High resolution optical mapping of the atria demonstrated reduced conduction velocity and action potential duration in aged hearts that were also graded by FI score. Furthermore, aged mice had increased interstitial fibrosis along with changes in regulators of extracellular matrix remodelling, which also correlated with frailty. These experiments demonstrate that aging results in changes in atrial structure and function that create a substrate for atrial arrhythmias. Importantly, these changes were heterogeneous due to differences in health status, which could be identified using an FI.
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Mademont-Soler I, Pinsach-Abuin M, Riuró H, Mates J, Pérez-Serra A, Coll M, Porres JM, del Olmo B, Iglesias A, Selga E, Picó F, Pagans S, Ferrer-Costa C, Sarquella-Brugada G, Arbelo E, Cesar S, Brugada J, Campuzano Ó, Brugada R. Large Genomic Imbalances in Brugada Syndrome. PLoS One 2016; 11:e0163514. [PMID: 27684715 PMCID: PMC5042553 DOI: 10.1371/journal.pone.0163514] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/09/2016] [Indexed: 01/01/2023] Open
Abstract
Purpose Brugada syndrome (BrS) is a form of cardiac arrhythmia which may lead to sudden cardiac death. The recommended genetic testing (direct sequencing of SCN5A) uncovers disease-causing SNVs and/or indels in ~20% of cases. Limited information exists about the frequency of copy number variants (CNVs) in SCN5A in BrS patients, and the role of CNVs in BrS-minor genes is a completely unexplored field. Methods 220 BrS patients with negative genetic results were studied to detect CNVs in SCN5A. 63 cases were also screened for CNVs in BrS-minor genes. Studies were performed by Multiplex ligation-dependent probe amplification or Next-Generation Sequencing (NGS). Results The detection rate for CNVs in SCN5A was 0.45% (1/220). The detected imbalance consisted of a duplication from exon 15 to exon 28, and could potentially explain the BrS phenotype. No CNVs were found in BrS-minor genes. Conclusion CNVs in current BrS-related genes are uncommon among BrS patients. However, as these rearrangements may underlie a portion of cases and they undergo unnoticed by traditional sequencing, an appealing alternative to conventional studies in these patients could be targeted NGS, including in a single experiment the study of SNVs, indels and CNVs in all the known BrS-related genes.
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Affiliation(s)
| | | | - Helena Riuró
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
| | - Jesus Mates
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
| | | | - Mònica Coll
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
| | | | - Bernat del Olmo
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
| | - Anna Iglesias
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
| | - Elisabet Selga
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
| | - Ferran Picó
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
| | - Sara Pagans
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
- Department of Medical Sciences, School of Medicine, University of Girona, Girona, Spain
| | | | | | - Elena Arbelo
- Arrhythmia Unit, Hospital Clinic de Barcelona, University of Barcelona, Barcelona, Spain
| | - Sergi Cesar
- Arrhythmia Unit, Hospital Clinic de Barcelona, University of Barcelona, Barcelona, Spain
| | - Josep Brugada
- Arrhythmia Unit, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
- Arrhythmia Unit, Hospital Clinic de Barcelona, University of Barcelona, Barcelona, Spain
| | - Óscar Campuzano
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
- Department of Medical Sciences, School of Medicine, University of Girona, Girona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Center, University of Girona-IDIBGI, Girona, Spain
- Department of Medical Sciences, School of Medicine, University of Girona, Girona, Spain
- Cardiovascular Genetics Unit, Hospital Josep Trueta, Girona, Spain
- * E-mail:
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Abstract
Somatic mosaicism, the occurrence and propagation of genetic variation in cell lineages after fertilization, is increasingly recognized to play a causal role in a variety of human diseases. We investigated the case of life-threatening arrhythmia in a 10-day-old infant with long QT syndrome (LQTS). Rapid genome sequencing suggested a variant in the sodium channel NaV1.5 encoded by SCN5A, NM_000335:c.5284G > T predicting p.(V1762L), but read depth was insufficient to be diagnostic. Exome sequencing of the trio confirmed read ratios inconsistent with Mendelian inheritance only in the proband. Genotyping of single circulating leukocytes demonstrated the mutation in the genomes of 8% of patient cells, and RNA sequencing of cardiac tissue from the infant confirmed the expression of the mutant allele at mosaic ratios. Heterologous expression of the mutant channel revealed significantly delayed sodium current with a dominant negative effect. To investigate the mechanism by which mosaicism might cause arrhythmia, we built a finite element simulation model incorporating Purkinje fiber activation. This model confirmed the pathogenic consequences of cardiac cellular mosaicism and, under the presenting conditions of this case, recapitulated 2:1 AV block and arrhythmia. To investigate the extent to which mosaicism might explain undiagnosed arrhythmia, we studied 7,500 affected probands undergoing commercial gene-panel testing. Four individuals with pathogenic variants arising from early somatic mutation events were found. Here we establish cardiac mosaicism as a causal mechanism for LQTS and present methods by which the general phenomenon, likely to be relevant for all genetic diseases, can be detected through single-cell analysis and next-generation sequencing.
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García IE, Prado P, Pupo A, Jara O, Rojas-Gómez D, Mujica P, Flores-Muñoz C, González-Casanova J, Soto-Riveros C, Pinto BI, Retamal MA, González C, Martínez AD. Connexinopathies: a structural and functional glimpse. BMC Cell Biol 2016; 17 Suppl 1:17. [PMID: 27228968 PMCID: PMC4896260 DOI: 10.1186/s12860-016-0092-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Mutations in human connexin (Cx) genes have been related to diseases, which we termed connexinopathies. Such hereditary disorders include nonsyndromic or syndromic deafness (Cx26, Cx30), Charcot Marie Tooth disease (Cx32), occulodentodigital dysplasia and cardiopathies (Cx43), and cataracts (Cx46, Cx50). Despite the clinical phenotypes of connexinopathies have been well documented, their pathogenic molecular determinants remain elusive. The purpose of this work is to identify common/uncommon patterns in channels function among Cx mutations linked to human diseases. To this end, we compiled and discussed the effect of mutations associated to Cx26, Cx32, Cx43, and Cx50 over gap junction channels and hemichannels, highlighting the function of the structural channel domains in which mutations are located and their possible role affecting oligomerization, gating and perm/selectivity processes.
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Affiliation(s)
- Isaac E García
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Pavel Prado
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Amaury Pupo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Oscar Jara
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Diana Rojas-Gómez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Paula Mujica
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Carolina Flores-Muñoz
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Jorge González-Casanova
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Carolina Soto-Riveros
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Bernardo I Pinto
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Mauricio A Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
| | - Carlos González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Agustín D Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.
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Franco D, Lozano-Velasco E, Aranega A. Gene regulatory networks in atrial fibrillation. World J Med Genet 2016; 6:1-16. [DOI: 10.5496/wjmg.v6.i1.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 12/15/2015] [Accepted: 02/17/2016] [Indexed: 02/06/2023] Open
Abstract
Atrial fibrillation (AF) is the most frequent arrhythmogenic syndrome in humans. With an estimate incidence of 1%-2% in the general population, AF raises up to almost 10%-12% in 80+ years. Thus, AF represents nowadays a highly prevalent medical problem generating a large economic burden. At the electrophysiological level, distinct mechanisms have been elucidated. Yet, despite its prevalence, the genetic and molecular culprits of this pandemic cardiac electrophysiological abnormality have remained largely obscure. Molecular genetics of AF familiar cases have demonstrated that single nucleotide mutations in distinct genes encoding for ion channels underlie the onset of AF, albeit such alterations only explain a minor subset of patients with AF. In recent years, analyses by means of genome-wide association studies have unraveled a more complex picture of the etiology of AF, pointing out to distinct cardiac-enriched transcription factors, as well as to other regulatory genes. Furthermore a new layer of regulatory mechanisms have emerged, i.e., post-transcriptional regulation mediated by non-coding RNA, which have been demonstrated to exert pivotal roles in cardiac electrophysiology. In this manuscript, we aim to provide a comprehensive review of the genetic regulatory networks that if impaired exert electrophysiological abnormalities that contribute to the onset, and subsequently, on self-perpetuation of AF.
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