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Li E, van der Heyden MAG. The network of cardiac K IR2.1: its function, cellular regulation, electrical signaling, diseases and new drug avenues. Naunyn Schmiedebergs Arch Pharmacol 2024:10.1007/s00210-024-03116-5. [PMID: 38683369 DOI: 10.1007/s00210-024-03116-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/19/2024] [Indexed: 05/01/2024]
Abstract
The functioning of the human heart relies on complex electrical and communication systems that coordinate cardiac contractions and sustain rhythmicity. One of the key players contributing to this intricate system is the KIR2.1 potassium ion channel, which is encoded by the KCNJ2 gene. KIR2.1 channels exhibit abundant expression in both ventricular myocytes and Purkinje fibers, exerting an important role in maintaining the balance of intracellular potassium ion levels within the heart. And by stabilizing the resting membrane potential and contributing to action potential repolarization, these channels have an important role in cardiac excitability also. Either gain- or loss-of-function mutations, but also acquired impairments of their function, are implicated in the pathogenesis of diverse types of cardiac arrhythmias. In this review, we aim to elucidate the system functions of KIR2.1 channels related to cellular electrical signaling, communication, and their contributions to cardiovascular disease. Based on this knowledge, we will discuss existing and new pharmacological avenues to modulate their function.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Yalelaan 50, 3584 CM, Utrecht, Netherlands.
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2
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Liu Q, Sun J, Dong Y, Li P, Wang J, Wang Y, Xu Y, Tian X, Wu B, He P, Yu Q, Lu X, Cao J. Tetramisole is a new I K1 channel agonist and exerts I K1 -dependent cardioprotective effects in rats. Pharmacol Res Perspect 2022; 10:e00992. [PMID: 35880674 PMCID: PMC9316008 DOI: 10.1002/prp2.992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 06/22/2022] [Accepted: 07/04/2022] [Indexed: 11/30/2022] Open
Abstract
Cardiac ischemia, hypoxia, arrhythmias, and heart failure share the common electrophysiological changes featured by the elevation of intracellular Ca2+ (Ca2+ overload) and inhibition of the inward rectifier potassium (IK1 ) channel. IK1 channel agonists have been considered a new type of anti-arrhythmia and cardioprotective agents. We predicted using a drug repurposing strategy that tetramisole (Tet), a known anthelminthic agent, was a new IK1 channel agonist. The present study aimed to experimentally identify the above prediction and further demonstrate that Tet has cardioprotective effects. Results of the whole-cell patch clamp technique showed that Tet at 1-100 μmol/L enhanced IK1 current, hyperpolarized resting potential (RP), and shortened action potential duration (APD) in isolated rat cardiomyocytes, while without effects on other ion channels or transporters. In adult Sprague-Dawley (SD) rats in vivo, Tet showed anti-arrhythmia and anticardiac remodeling effects, respectively, in the coronary ligation-induced myocardial infarction model and isoproterenol (Iso, i.p., 3 mg/kg/day, 10 days) infusion-induced cardiac remodeling model. Tet also showed anticardiomyocyte remodeling effect in Iso (1 μmol/L) infused adult rat ventricular myocytes or cultured H9c2 (2-1) cardiomyocytes. Tet at 0.54 mg/kg in vivo or 30 μmol/L in vitro showed promising protections on acute ischemic arrhythmias, myocardial hypertrophy, and fibrosis. Molecular docking was performed and identified the selective binding of Tet with Kir2.1. The cardioprotection of Tet was associated with the facilitation of IK1 channel forward trafficking, deactivation of PKA signaling, and inhibition of intracellular calcium overload. Enhancing IK1 may play dual roles in anti-arrhythmia and antiventricular remodeling mediated by restoration of Ca2+ homeostasis.
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Affiliation(s)
- Qinghua Liu
- Department of PathophysiologyShanxi Medical UniversityTaiyuanChina
| | - Jiaxing Sun
- Department of PathophysiologyShanxi Medical UniversityTaiyuanChina
| | - Yangdou Dong
- Department of PathophysiologyShanxi Medical UniversityTaiyuanChina
| | - Pan Li
- Department of PathophysiologyShanxi Medical UniversityTaiyuanChina
| | - Jin Wang
- Key Laboratory of Cellular Physiology, Ministry of EducationShanxi Medical UniversityTaiyuanChina
- Department of PhysiologyShanxi Medical UniversityTaiyuanChina
| | - Yulan Wang
- Key Laboratory of Cellular Physiology, Ministry of EducationShanxi Medical UniversityTaiyuanChina
- Department of PhysiologyShanxi Medical UniversityTaiyuanChina
| | - Yanwu Xu
- Department of BiochemistryShanghai University of Traditional Chinese MedicineShanghaiChina
| | - Xinrui Tian
- Department of Respiratory and Critical Care MedicineSecond Hospital of Shanxi Medical UniversityTaiyuanChina
| | - Bowei Wu
- Key Laboratory of Cellular Physiology, Ministry of EducationShanxi Medical UniversityTaiyuanChina
- Department of PhysiologyShanxi Medical UniversityTaiyuanChina
| | - Peifeng He
- Shanxi Key Laboratory of Big Data for Clinical Decision Research, School of ManagementShanxi Medical UniversityTaiyuanChina
| | - Qi Yu
- Shanxi Key Laboratory of Big Data for Clinical Decision Research, School of ManagementShanxi Medical UniversityTaiyuanChina
| | - Xuechun Lu
- Department of Hematology, The Second Medical Center, Chinese PLA General HospitalNational clinical research center for geriatric diseaseBeijingChina
| | - Jimin Cao
- Key Laboratory of Cellular Physiology, Ministry of EducationShanxi Medical UniversityTaiyuanChina
- Department of PhysiologyShanxi Medical UniversityTaiyuanChina
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3
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Manuel AIM, Gutiérrez LK, Pedrosa MLV, Uréndez FMC, Jiménez FJB, Carrascoso IM, Pérez PS, Macías Á, Jalife J. Molecular stratification of arrhythmogenic mechanisms in the Andersen Tawil Syndrome. Cardiovasc Res 2022; 119:919-932. [PMID: 35892314 PMCID: PMC10153646 DOI: 10.1093/cvr/cvac118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 06/20/2022] [Accepted: 07/01/2022] [Indexed: 11/12/2022] Open
Abstract
Andersen Tawil Syndrome (ATS) is a rare inheritable disease associated with loss-of-function mutations in KCNJ2, the gene coding the strong inward rectifier potassium channel Kir2.1, which forms an essential membrane protein controlling cardiac excitability. ATS is usually marked by a triad of periodic paralysis, life-threatening cardiac arrhythmias and dysmorphic features, but its expression is variable and not all patients with a phenotype linked to ATS have a known genetic alteration. The mechanisms underlying this arrhythmogenic syndrome are poorly understood. Knowing such mechanisms would be essential to distinguish ATS from other channelopathies with overlapping phenotypes and to develop individualized therapies. For example, the recently suggested role of Kir2.1 as a countercurrent to sarcoplasmic calcium reuptake might explain the arrhythmogenic mechanisms of ATS and its overlap with catecholaminergic polymorphic ventricular tachycardia (CPVT). Here we summarize current knowledge on the mechanisms of arrhythmias leading to sudden cardiac death in ATS. We first provide an overview of the syndrome and its pathophysiology, from the patient´s bedside to the protein, and discuss the role of essential regulators and interactors that could play a role in cases of ATS. The review highlights novel ideas related to some post-translational channel interactions with partner proteins that might help define the molecular bases of the arrhythmia phenotype. We then propose a new all-embracing classification of the currently known ATS loss-of-function mutations according to their position in the Kir2.1 channel structure and their functional implications. We also discuss specific ATS pathogenic variants, their clinical manifestations and treatment stratification. The goal is to provide a deeper mechanistic understanding of the syndrome toward the development of novel targets and personalized treatment strategies.
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Affiliation(s)
| | - Lilian K Gutiérrez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | | | | | - Francisco José Bermúdez Jiménez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain.,Departamento de Cardiología, Hospital Virgen de las Nieves, GranadaSpain
| | | | - Patricia Sánchez Pérez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | - Álvaro Macías
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain
| | - José Jalife
- Centro Nacional de Investigaciones Cardiovasculares (CNIC) Carlos III, 28029 Madrid, Spain.,CIBER de Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain.,Departments of Medicine and Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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4
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Eckhardt LL. Arrhythmogenesis and Prolonged Repolarization From Synthetic Opioids: Finally Sorted? J Am Heart Assoc 2022; 11:e025778. [PMID: 35658484 PMCID: PMC9238742 DOI: 10.1161/jaha.122.025778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lee L Eckhardt
- Department of Medicine University of Wisconsin-Madison Madison WI
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5
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Walsh R, Adler A, Amin AS, Abiusi E, Care M, Bikker H, Amenta S, Feilotter H, Nannenberg EA, Mazzarotto F, Trevisan V, Garcia J, Hershberger RE, Perez MV, Sturm AC, Ware JS, Zareba W, Novelli V, Wilde AAM, Gollob MH. Evaluation of gene validity for CPVT and short QT syndrome in sudden arrhythmic death. Eur Heart J 2022; 43:1500-1510. [PMID: 34557911 PMCID: PMC9009401 DOI: 10.1093/eurheartj/ehab687] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/11/2021] [Accepted: 09/09/2021] [Indexed: 12/02/2022] Open
Abstract
AIMS Catecholaminergic polymorphic ventricular tachycardia (CPVT) and short QT syndrome (SQTS) are inherited arrhythmogenic disorders that can cause sudden death. Numerous genes have been reported to cause these conditions, but evidence supporting these gene-disease relationships varies considerably. To ensure appropriate utilization of genetic information for CPVT and SQTS patients, we applied an evidence-based reappraisal of previously reported genes. METHODS AND RESULTS Three teams independently curated all published evidence for 11 CPVT and 9 SQTS implicated genes using the ClinGen gene curation framework. The results were reviewed by a Channelopathy Expert Panel who provided the final classifications. Seven genes had definitive to moderate evidence for disease causation in CPVT, with either autosomal dominant (RYR2, CALM1, CALM2, CALM3) or autosomal recessive (CASQ2, TRDN, TECRL) inheritance. Three of the four disputed genes for CPVT (KCNJ2, PKP2, SCN5A) were deemed by the Expert Panel to be reported for phenotypes that were not representative of CPVT, while reported variants in a fourth gene (ANK2) were too common in the population to be disease-causing. For SQTS, only one gene (KCNH2) was classified as definitive, with three others (KCNQ1, KCNJ2, SLC4A3) having strong to moderate evidence. The majority of genetic evidence for SQTS genes was derived from very few variants (five in KCNJ2, two in KCNH2, one in KCNQ1/SLC4A3). CONCLUSIONS Seven CPVT and four SQTS genes have valid evidence for disease causation and should be included in genetic testing panels. Additional genes associated with conditions that may mimic clinical features of CPVT/SQTS have potential utility for differential diagnosis.
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Affiliation(s)
- Roddy Walsh
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Arnon Adler
- Division of Cardiology, Department of Medicine, Peter Munk Cardiac Centre, University Health Network, University of Toronto, 585 University Avenue, Toronto, ON M5G 2N2, Canada
| | - Ahmad S Amin
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Emanuela Abiusi
- Fondazione Policlinico Universitario A. Gemelli IRCCS and Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, L.go F. Vito 1, Rome 00168, Italy
| | - Melanie Care
- Division of Cardiology, Toronto General Hospital, The Toronto General Hospital Research Institute, University Health Network, University of Toronto, 200 Elizabeth St, Toronto, ON M5G 2C4, Canada
- Department of Molecular Genetics, University of Toronto, 1 King's College Cir, Toronto, ON M5S 1A8, Canada
| | - Hennie Bikker
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Simona Amenta
- Fondazione Policlinico Universitario A. Gemelli IRCCS and Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, L.go F. Vito 1, Rome 00168, Italy
| | - Harriet Feilotter
- Department of Pathology and Molecular Medicine, Queen's University, 88 Stuart Street, Kingston, ON K7L 3N6, Canada
| | - Eline A Nannenberg
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, Amsterdam 1105 AZ, The Netherlands
| | - Francesco Mazzarotto
- Department of Experimental and Clinical Medicine, University of Florence, Viale Pieraccini 6, Florence 50139, Italy
- Faculty of Medicine, National Heart & Lung Institute, Imperial College London, Dovehouse St, London SW3 6LY, UK
- Cardiovascular Research Centre, Royal Brompton & Harefield Hospitals, Sydney St, London SW3 6NP, UK
| | - Valentina Trevisan
- Fondazione Policlinico Universitario A. Gemelli IRCCS and Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, L.go F. Vito 1, Rome 00168, Italy
| | - John Garcia
- Invitae Corp., 1400 16th St, San Francisco, CA 94103, USA
| | - Ray E Hershberger
- Division of Human Genetics, Department of Internal Medicine, The Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, 473 W 12th Ave, Columbus, OH 43210, USA
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, 473 W 12th Ave, Columbus, OH 43210, USA
| | - Marco V Perez
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, 300 Pasteur Dr, Stanford, CA 94305, USA
| | - Amy C Sturm
- Geisinger Genomic Medicine Institute, 100 N Academy Ave, Danville, PA 17822, USA
| | - James S Ware
- Faculty of Medicine, National Heart & Lung Institute, Imperial College London, Dovehouse St, London SW3 6LY, UK
- Cardiovascular Research Centre, Royal Brompton & Harefield Hospitals, Sydney St, London SW3 6NP, UK
- Cardiovascular Genomics and Precision Medicine, MRC London Institute of Medical Sciences, Imperial College London, Du Cane Rd, London W12 0NN, UK
| | - Wojciech Zareba
- Cardiology Unit of the Department of Medicine, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY 14642, USA
| | - Valeria Novelli
- Fondazione Policlinico Universitario A. Gemelli IRCCS and Istituto di Medicina Genomica, Università Cattolica del Sacro Cuore, L.go F. Vito 1, Rome 00168, Italy
| | - Arthur A M Wilde
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, University of Amsterdam, Heart Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Michael H Gollob
- Division of Cardiology, Toronto General Hospital, The Toronto General Hospital Research Institute, University Health Network, University of Toronto, 200 Elizabeth St, Toronto, ON M5G 2C4, Canada
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6
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Martínez-Barrios E, Cesar S, Cruzalegui J, Hernandez C, Arbelo E, Fiol V, Brugada J, Brugada R, Campuzano O, Sarquella-Brugada G. Clinical Genetics of Inherited Arrhythmogenic Disease in the Pediatric Population. Biomedicines 2022; 10:106. [PMID: 35052786 PMCID: PMC8773373 DOI: 10.3390/biomedicines10010106] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/27/2021] [Accepted: 12/31/2021] [Indexed: 12/19/2022] Open
Abstract
Sudden death is a rare event in the pediatric population but with a social shock due to its presentation as the first symptom in previously healthy children. Comprehensive autopsy in pediatric cases identify an inconclusive cause in 40-50% of cases. In such cases, a diagnosis of sudden arrhythmic death syndrome is suggested as the main potential cause of death. Molecular autopsy identifies nearly 30% of cases under 16 years of age carrying a pathogenic/potentially pathogenic alteration in genes associated with any inherited arrhythmogenic disease. In the last few years, despite the increasing rate of post-mortem genetic diagnosis, many families still remain without a conclusive genetic cause of the unexpected death. Current challenges in genetic diagnosis are the establishment of a correct genotype-phenotype association between genes and inherited arrhythmogenic disease, as well as the classification of variants of uncertain significance. In this review, we provide an update on the state of the art in the genetic diagnosis of inherited arrhythmogenic disease in the pediatric population. We focus on emerging publications on gene curation for genotype-phenotype associations, cases of genetic overlap and advances in the classification of variants of uncertain significance. Our goal is to facilitate the translation of genetic diagnosis to the clinical area, helping risk stratification, treatment and the genetic counselling of families.
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Affiliation(s)
- Estefanía Martínez-Barrios
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Sergi Cesar
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - José Cruzalegui
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Clara Hernandez
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Elena Arbelo
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, 08036 Barcelona, Spain
| | - Victoria Fiol
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
| | - Josep Brugada
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Arrhythmias Unit, Hospital Clinic, University of Barcelona-IDIBAPS, 08036 Barcelona, Spain
| | - Ramon Brugada
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
- Cardiology Service, Hospital Josep Trueta, University of Girona, 17007 Girona, Spain
| | - Oscar Campuzano
- Centro de Investigación Biomédica en Red, Enfermedades Cardiovasculares (CIBERCV), 28029 Madrid, Spain; (E.A.); (R.B.)
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
- Cardiovascular Genetics Center, University of Girona-IDIBGI, 17190 Girona, Spain
| | - Georgia Sarquella-Brugada
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, 08007 Barcelona, Spain; (E.M.-B.); (S.C.); (J.C.); (C.H.); (V.F.); (J.B.)
- Medical Science Department, School of Medicine, University of Girona, 17004 Girona, Spain
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7
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Le Tanno P, Folacci M, Revilloud J, Faivre L, Laurent G, Pinson L, Amedro P, Millat G, Janin A, Vivaudou M, Roux-Buisson N, Fauré J. Characterization of Loss-Of-Function KCNJ2 Mutations in Atypical Andersen Tawil Syndrome. Front Genet 2021; 12:773177. [PMID: 34899860 PMCID: PMC8655864 DOI: 10.3389/fgene.2021.773177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/03/2021] [Indexed: 12/02/2022] Open
Abstract
Andersen-Tawil Syndrome (ATS) is a rare disease defined by the association of cardiac arrhythmias, periodic paralysis and dysmorphic features, and is caused by KCNJ2 loss-of-function mutations. However, when extracardiac symptoms are atypical or absent, the patient can be diagnosed with Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT), a rare arrhythmia at high risk of sudden death, mostly due to RYR2 mutations. The identification of KCNJ2 variants in CPVT suspicion is very rare but important because beta blockers, the cornerstone of CPVT therapy, could be less efficient. We report here the cases of two patients addressed for CPVT-like phenotypes. Genetic investigations led to the identification of p. Arg82Trp and p. Pro186Gln de novo variants in the KCNJ2 gene. Functional studies showed that both variants forms of Kir2.1 monomers act as dominant negative and drastically reduced the activity of the tetrameric channel. We characterize here a new pathogenic variant (p.Pro186Gln) of KCNJ2 gene and highlight the interest of accurate cardiologic evaluation and of attention to extracardiac signs to distinguish CPVT from atypical ATS, and guide therapeutic decisions. We also confirm that the KCNJ2 gene must be investigated during CPVT molecular analysis.
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Affiliation(s)
- Pauline Le Tanno
- Université Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Mathilde Folacci
- CEA, CNRS, Institut de Biologie Structurale, Université Grenoble Alpes, Grenoble, France
| | - Jean Revilloud
- CEA, CNRS, Institut de Biologie Structurale, Université Grenoble Alpes, Grenoble, France
| | - Laurence Faivre
- Medical Genetics Department, Dijon Bourgogne University Hospital, François Mitterand Hospital, Dijon, France
| | - Gabriel Laurent
- Cardiology Department, Dijon Bourgogne University Hospital, François Mitterand Hospital, Dijon, France
| | - Lucile Pinson
- Medical Genetics Department, University Hospital, Montpellier, France.,Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Montpellier, France.,Genetic Department for Rare Diseases and Personalized Medicine, Clinical Division, Montpellier, France
| | - Pascal Amedro
- Pediatric and Congenital Cardiology Department, Clinical Investigation Centre, PhyMedExp, CNRS, INSERM, University of Montpellier, University Hospital, Montpellier, France
| | - Gilles Millat
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France
| | - Alexandre Janin
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France
| | - Michel Vivaudou
- CEA, CNRS, Institut de Biologie Structurale, Université Grenoble Alpes, Grenoble, France
| | - Nathalie Roux-Buisson
- Université Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Julien Fauré
- Université Grenoble Alpes, Inserm, U1216, CHU Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
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8
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Brown KA, Anderson C, Reilly L, Sondhi K, Ge Y, Eckhardt LL. Proteomic Analysis of the Functional Inward Rectifier Potassium Channel (Kir) 2.1 Reveals Several Novel Phosphorylation Sites. Biochemistry 2021; 60:3292-3301. [PMID: 34676745 DOI: 10.1021/acs.biochem.1c00555] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Membrane proteins represent a large family of proteins that perform vital physiological roles and represent key drug targets. Despite their importance, bioanalytical methods aiming to comprehensively characterize the post-translational modification (PTM) of membrane proteins remain challenging compared to other classes of proteins in part because of their inherent low expression and hydrophobicity. The inward rectifier potassium channel (Kir) 2.1, an integral membrane protein, is critical for the maintenance of the resting membrane potential and phase-3 repolarization of the cardiac action potential in the heart. The importance of this channel to cardiac physiology is highlighted by the recognition of several sudden arrhythmic death syndromes, Andersen-Tawil and short QT syndromes, which are associated with loss or gain of function mutations in Kir2.1, often triggered by changes in the β-adrenergic tone. Therefore, understanding the PTMs of this channel (particularly β-adrenergic tone-driven phosphorylation) is important for arrhythmia prevention. Here, we developed a proteomic method, integrating both top-down (intact protein) and bottom-up (after enzymatic digestion) proteomic analyses, to characterize the PTMs of recombinant wild-type and mutant Kir2.1, successfully mapping five novel sites of phosphorylation and confirming a sixth site. Our study provides a framework for future work to assess the role of PTMs in regulating Kir2.1 functions.
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Affiliation(s)
- Kyle A Brown
- Department of Surgery, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.,Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Corey Anderson
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Kunal Sondhi
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Ying Ge
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States.,Human Proteomics Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Lee L Eckhardt
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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9
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Sleiman Y, Lacampagne A, Meli AC. "Ryanopathies" and RyR2 dysfunctions: can we further decipher them using in vitro human disease models? Cell Death Dis 2021; 12:1041. [PMID: 34725342 PMCID: PMC8560800 DOI: 10.1038/s41419-021-04337-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/08/2021] [Accepted: 10/14/2021] [Indexed: 12/23/2022]
Abstract
The regulation of intracellular calcium (Ca2+) homeostasis is fundamental to maintain normal functions in many cell types. The ryanodine receptor (RyR), the largest intracellular calcium release channel located on the sarco/endoplasmic reticulum (SR/ER), plays a key role in the intracellular Ca2+ handling. Abnormal type 2 ryanodine receptor (RyR2) function, associated to mutations (ryanopathies) or pathological remodeling, has been reported, not only in cardiac diseases, but also in neuronal and pancreatic disorders. While animal models and in vitro studies provided valuable contributions to our knowledge on RyR2 dysfunctions, the human cell models derived from patients’ cells offer new hope for improving our understanding of human clinical diseases and enrich the development of great medical advances. We here discuss the current knowledge on RyR2 dysfunctions associated with mutations and post-translational remodeling. We then reviewed the novel human cellular technologies allowing the correlation of patient’s genome with their cellular environment and providing approaches for personalized RyR-targeted therapeutics.
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Affiliation(s)
- Yvonne Sleiman
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Alain Lacampagne
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Albano C Meli
- PhyMedExp, University of Montpellier, INSERM, CNRS, Montpellier, France.
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10
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Kamga MVK, Reppel M, Hescheler J, Nguemo F. Modeling genetic cardiac channelopathies using induced pluripotent stem cells - Status quo from an electrophysiological perspective. Biochem Pharmacol 2021; 192:114746. [PMID: 34461117 DOI: 10.1016/j.bcp.2021.114746] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 12/15/2022]
Abstract
Long QT syndrome (LQTS), Brugada syndrome (BrS), and catecholaminergic polymorphic ventricular tachycardia (CPVT) are genetic diseases of the heart caused by mutations in specific cardiac ion channels and are characterized by paroxysmal arrhythmias, which can deteriorate into ventricular fibrillation. In LQTS3 and BrS different mutations in the SCN5A gene lead to a gain-or a loss-of-function of the voltage-gated sodium channel Nav1.5, respectively. Although sharing the same gene mutation, these syndromes are characterized by different clinical manifestations and functional perturbations and in some cases even present an overlapping clinical phenotype. Several studies have shown that Na+ current abnormalities in LQTS3 and BrS can also cause Ca2+-signaling aberrancies in cardiomyocytes (CMs). Abnormal Ca2+ homeostasis is also the main feature of CPVT which is mostly caused by heterozygous mutations in the RyR2 gene. Large numbers of disease-causing mutations were identified in RyR2 and SCN5A but it is not clear how different variants in the SCN5A gene produce different clinical syndromes and if in CPVT Ca2+ abnormalities and drug sensitivities vary depending on the mutation site in the RyR2. These questions can now be addressed by using patient-specific in vitro models of these diseases based on induced pluripotent stem cells (iPSCs). In this review, we summarize different insights gained from these models with a focus on electrophysiological perturbations caused by different ion channel mutations and discuss how will this knowledge help develop better stratification and more efficient personalized therapies for these patients.
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Affiliation(s)
- Michelle Vanessa Kapchoup Kamga
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Michael Reppel
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany; Praxis für Kardiologie und Angiologie, Landsberg am Lech, Germany
| | - Jürgen Hescheler
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Filomain Nguemo
- Center for Physiology and Pathophysiology, Institute for Neurophysiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
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11
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Kallas D, Lamba A, Roston TM, Arslanova A, Franciosi S, Tibbits GF, Sanatani S. Pediatric Catecholaminergic Polymorphic Ventricular Tachycardia: A Translational Perspective for the Clinician-Scientist. Int J Mol Sci 2021; 22:ijms22179293. [PMID: 34502196 PMCID: PMC8431429 DOI: 10.3390/ijms22179293] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/21/2021] [Accepted: 08/24/2021] [Indexed: 12/17/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare and potentially lethal inherited arrhythmia disease characterized by exercise or emotion-induced bidirectional or polymorphic ventricular tachyarrhythmias. The median age of disease onset is reported to be approximately 10 years of age. The majority of CPVT patients have pathogenic variants in the gene encoding the cardiac ryanodine receptor, or calsequestrin 2. These lead to mishandling of calcium in cardiomyocytes resulting in after-depolarizations, and ventricular arrhythmias. Disease severity is particularly pronounced in younger individuals who usually present with cardiac arrest and arrhythmic syncope. Risk stratification is imprecise and long-term prognosis on therapy is unknown despite decades of research focused on pediatric CPVT populations. The purpose of this review is to summarize contemporary data on pediatric CPVT, highlight knowledge gaps and present future research directions for the clinician-scientist to address.
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Affiliation(s)
- Dania Kallas
- British Columbia Children’s Hospital Heart Center, 1F9-4480 Oak St., Vancouver, BC V6H 3V4, Canada; (D.K.); (A.L.); (T.M.R.); (S.F.)
| | - Avani Lamba
- British Columbia Children’s Hospital Heart Center, 1F9-4480 Oak St., Vancouver, BC V6H 3V4, Canada; (D.K.); (A.L.); (T.M.R.); (S.F.)
| | - Thomas M. Roston
- British Columbia Children’s Hospital Heart Center, 1F9-4480 Oak St., Vancouver, BC V6H 3V4, Canada; (D.K.); (A.L.); (T.M.R.); (S.F.)
- Clinician-Investigator Program, University of British Columbia, 2016-1874 East Mall, Vancouver, BC V6T 1Z1, Canada
| | - Alia Arslanova
- Cellular and Regenerative Medicine Centre, British Columbia Children’s Hospital Research Institute, 938 W 28th Ave, Vancouver, BC V5Z 4H4, Canada; (A.A.); (G.F.T.)
- Molecular Cardiac Physiology Group, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada
| | - Sonia Franciosi
- British Columbia Children’s Hospital Heart Center, 1F9-4480 Oak St., Vancouver, BC V6H 3V4, Canada; (D.K.); (A.L.); (T.M.R.); (S.F.)
| | - Glen F. Tibbits
- Cellular and Regenerative Medicine Centre, British Columbia Children’s Hospital Research Institute, 938 W 28th Ave, Vancouver, BC V5Z 4H4, Canada; (A.A.); (G.F.T.)
- Molecular Cardiac Physiology Group, Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada
| | - Shubhayan Sanatani
- British Columbia Children’s Hospital Heart Center, 1F9-4480 Oak St., Vancouver, BC V6H 3V4, Canada; (D.K.); (A.L.); (T.M.R.); (S.F.)
- Correspondence:
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12
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Reilly L, Eckhardt LL. Cardiac potassium inward rectifier Kir2: Review of structure, regulation, pharmacology, and arrhythmogenesis. Heart Rhythm 2021; 18:1423-1434. [PMID: 33857643 PMCID: PMC8328935 DOI: 10.1016/j.hrthm.2021.04.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/23/2021] [Accepted: 04/06/2021] [Indexed: 12/17/2022]
Abstract
Potassium inward rectifier channel Kir2 is an important component of terminal cardiac repolarization and resting membrane stability. This functionality is part of balanced cardiac excitability and is a defining feature of excitable cardiac membranes. “Gain-of-function” or “loss-of-function” mutations in KCNJ2, the gene encoding Kir2.1, cause genetic sudden cardiac death syndromes, and loss of the Kir2 current IK1 is a major contributing factor to arrhythmogenesis in failing human hearts. Here we provide a contemporary review of the functional structure, physiology, and pharmacology of Kir2 channels. Beyond the structure and functional relationships, we will focus on the elements of clinically used drugs that block the channel and the implications for treatment of atrial fibrillation with IK1-blocking agents. We will also review the clinical disease entities associated with KCNJ2 mutations and the growing area of research into associated arrhythmia mechanisms. Lastly, the presence of Kir2 channels has become a tipping point for electrical maturity in induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) and highlights the significance of understanding why Kir2 in iPS-CMs is important to consider for Comprehensive In Vitro Proarrhythmia Assay and drug safety testing.
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Affiliation(s)
- Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Lee L Eckhardt
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
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13
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Pérez-Riera AR, Barbosa-Barros R, Samesina N, Pastore CA, Scanavacca M, Daminello-Raimundo R, de Abreu LC, Nikus K, Brugada P. Andersen-Tawil Syndrome: A Comprehensive Review. Cardiol Rev 2021; 29:165-77. [PMID: 32947483 DOI: 10.1097/CRD.0000000000000326] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Andersen-Tawil syndrome (ATS) is a very rare orphan genetic multisystem channelopathy without structural heart disease (with rare exceptions). ATS type 1 is inherited in an autosomal dominant fashion and is caused by mutations in the KCNJ2 gene, which encodes the α subunit of the K+ channel protein Kir2.1 (in ≈ 50-60% of cases). ATS type 2 is in turn linked to a rare mutation in the KCNJ5-GIRK4 gene that encodes the G protein-sensitive-activated inwardly rectifying K+ channel Kir3.4 (15%), which carries the acetylcholine-induced potassium current. About 30% of cases are de novo/sporadic, suggesting that additional as-yet unidentified genes also cause the disorder. A triad of periodic muscle paralysis, repolarization changes in the electrocardiogram, and structural body changes characterize ATS. The typical muscular change is episodic flaccid muscle weakness. Prolongation of the QU/QUc intervals and normal or minimally prolonged QT/QTc intervals with a tendency to ventricular arrhythmias are typical repolarization changes. Bidirectional ventricular tachycardia is the hallmark ventricular arrhythmia, but also premature ventricular contractions, and rarely, polymorphic ventricular tachycardia of torsade de pointes type may be present. Patients with ATS have characteristic physical developmental dysmorphisms that affect the face, skull, limbs, thorax, and stature. Mild learning difficulties and a distinct neurocognitive phenotype (deficits in executive function and abstract reasoning) have been described. About 60% of affected individuals have all features of the major triad. The purpose of this review is to present historical aspects, nomenclature (observations/criticisms), epidemiology, genetics, electrocardiography, arrhythmias, electrophysiological mechanisms, diagnostic criteria/clues of periodic paralysis, prognosis, and management of ATS.
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14
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Köffer J, Scheiper-Welling S, Verhoff MA, Bajanowski T, Kauferstein S. Post-mortem genetic investigation of cardiac disease-associated genes in sudden infant death syndrome (SIDS) cases. Int J Legal Med 2021; 135:207-12. [PMID: 32789579 DOI: 10.1007/s00414-020-02394-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/03/2020] [Indexed: 12/29/2022]
Abstract
The sudden infant death syndrome (SIDS) is one of the leading causes of postneonatal infant death. It has been shown that there exists a complex relationship between SIDS and inherited cardiac disease. Next-generation sequencing and surveillance of cardiac channelopathy and cardiomyopathy genes represent an important tool for investigating the cause of death in SIDS cases. In the present study, targeted sequencing of 80 genes associated with genetic heart diseases in a cohort of 31 SIDS cases was performed. To determine the spectrum and prevalence of genetic heart disease associated mutations as a potential monogenic basis for SIDS, a stringent variant classification was applied and the percentage of rare (minor allele frequency ≤ 0.2%) and ultra-rare variants (minor allele frequency ≤ 0.005%) in these genes was assessed. With a minor allele frequency of ≤ 0.005%, about 20% of the SIDS cases exhibited a variant of uncertain significance (VUS), but in only 6% of these cases, gene variants proved to be “potentially informative.” The present study shows the importance of careful variant interpretation. Applying stringent criteria misinterpretations are avoided, as the results of genetic analyses may have an important impact of the family members involved.
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15
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Reilly L, Alvarado FJ, Lang D, Abozeid S, Van Ert H, Spellman C, Warden J, Makielski JC, Glukhov AV, Eckhardt LL. Genetic Loss of IK1 Causes Adrenergic-Induced Phase 3 Early Afterdepolariz ations and Polymorphic and Bidirectional Ventricular Tachycardia. Circ Arrhythm Electrophysiol 2020; 13:e008638. [PMID: 32931337 DOI: 10.1161/circep.120.008638] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Arrhythmia syndromes associated with KCNJ2 mutations have been described clinically; however, little is known of the underlying arrhythmia mechanism. We create the first patient inspired KCNJ2 transgenic mouse and study effects of this mutation on cardiac function, IK1, and Ca2+ handling, to determine the underlying cellular arrhythmic pathogenesis. METHODS A cardiac-specific KCNJ2-R67Q mouse was generated and bred for heterozygosity (R67Q+/-). Echocardiography was performed at rest, under anesthesia. In vivo ECG recording and whole heart optical mapping of intact hearts was performed before and after adrenergic stimulation in wild-type (WT) littermate controls and R67Q+/- mice. IK1 measurements, action potential characterization, and intracellular Ca2+ imaging from isolated ventricular myocytes at baseline and after adrenergic stimulation were performed in WT and R67Q+/- mice. RESULTS R67Q+/- mice (n=17) showed normal cardiac function, structure, and baseline electrical activity compared with WT (n=10). Following epinephrine and caffeine, only the R67Q+/- mice had bidirectional ventricular tachycardia, ventricular tachycardia, frequent ventricular ectopy, and/or bigeminy and optical mapping demonstrated high prevalence of spontaneous and sustained ventricular arrhythmia. Both R67Q+/- (n=8) and WT myocytes (n=9) demonstrated typical n-shaped IK1 IV relationship; however, following isoproterenol, max outward IK1 increased by ≈20% in WT but decreased by ≈24% in R67Q+/- (P<0.01). R67Q+/- myocytes (n=5) demonstrated prolonged action potential duration at 90% repolarization and after 10 nmol/L isoproterenol compared with WT (n=7; P<0.05). Ca2+ transient amplitude, 50% decay rate, and sarcoplasmic reticulum Ca2+ content were not different between WT (n=18) and R67Q+/- (n=16) myocytes. R67Q+/- myocytes (n=10) under adrenergic stimulation showed frequent spontaneous development of early afterdepolarizations that occurred at phase 3 of action potential repolarization. CONCLUSIONS KCNJ2 mutation R67Q+/- causes adrenergic-dependent loss of IK1 during terminal repolarization and vulnerability to phase 3 early afterdepolarizations. This model clarifies a heretofore unknown arrhythmia mechanism and extends our understanding of treatment implications for patients with KCNJ2 mutation.
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Affiliation(s)
- Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Francisco J Alvarado
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Di Lang
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Sara Abozeid
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Hannah Van Ert
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Cordell Spellman
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Jarrett Warden
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Jonathan C Makielski
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Alexey V Glukhov
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
| | - Lee L Eckhardt
- Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison
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16
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Handklo-Jamal R, Meisel E, Yakubovich D, Vysochek L, Beinart R, Glikson M, McMullen JR, Dascal N, Nof E, Oz S. Andersen-Tawil Syndrome Is Associated With Impaired PIP 2 Regulation of the Potassium Channel Kir2.1. Front Pharmacol 2020; 11:672. [PMID: 32499698 PMCID: PMC7243181 DOI: 10.3389/fphar.2020.00672] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 04/23/2020] [Indexed: 11/13/2022] Open
Abstract
Andersen-Tawil syndrome (ATS) type-1 is associated with loss-of-function mutations in KCNJ2 gene. KCNJ2 encodes the tetrameric inward-rectifier potassium channel Kir2.1, important to the resting phase of the cardiac action potential. Kir-channels' activity requires interaction with the agonist phosphatidylinositol-4,5-bisphosphate (PIP2). Two mutations were identified in ATS patients, V77E in the cytosolic N-terminal "slide helix" and M307V in the C-terminal cytoplasmic gate structure "G-loop." Current recordings in Kir2.1-expressing HEK cells showed that each of the two mutations caused Kir2.1 loss-of-function. Biotinylation and immunostaining showed that protein expression and trafficking of Kir2.1 to the plasma membrane were not affected by the mutations. To test the functional effect of the mutants in a heterozygote set, Kir2.1 dimers were prepared. Each dimer was composed of two Kir2.1 subunits joined with a flexible linker (i.e. WT-WT, WT dimer; WT-V77E and WT-M307V, mutant dimer). A tetrameric assembly of Kir2.1 is expected to include two dimers. The protein expression and the current density of WT dimer were equally reduced to ~25% of the WT monomer. Measurements from HEK cells and Xenopus oocytes showed that the expression of either WT-V77E or WT-M307V yielded currents of only about 20% compared to the WT dimer, supporting a dominant-negative effect of the mutants. Kir2.1 sensitivity to PIP2 was examined by activating the PIP2 specific voltage-sensitive phosphatase (VSP) that induced PIP2 depletion during current recordings, in HEK cells and Xenopus oocytes. PIP2 depletion induced a stronger and faster decay in Kir2.1 mutant dimers current compared to the WT dimer. BGP-15, a drug that has been demonstrated to have an anti-arrhythmic effect in mice, stabilized the Kir2.1 current amplitude following VSP-induced PIP2 depletion in cells expressing WT or mutant dimers. This study underlines the implication of mutations in cytoplasmic regions of Kir2.1. A newly developed calibrated VSP activation protocol enabled a quantitative assessment of changes in PIP2 regulation caused by the mutations. The results suggest an impaired function and a dominant-negative effect of the Kir2.1 variants that involve an impaired regulation by PIP2. This study also demonstrates that BGP-15 may be beneficial in restoring impaired Kir2.1 function and possibly in treating ATS symptoms.
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Affiliation(s)
| | - Eshcar Meisel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Heart Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Daniel Yakubovich
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Neonatology Department, Schneider Children's Medical Center, Petah-Tikva, Israel
| | | | - Roy Beinart
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Heart Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Michael Glikson
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Heart Center, Sheba Medical Center, Ramat-Gan, Israel
| | | | - Nathan Dascal
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eyal Nof
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Heart Center, Sheba Medical Center, Ramat-Gan, Israel
| | - Shimrit Oz
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Heart Center, Sheba Medical Center, Ramat-Gan, Israel
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17
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Nguyen D, Ferns SJ. Asymptomatic ventricular tachycardia: diagnostic pitfalls of Andersen-Tawil syndrome-a case report. Eur Heart J Case Rep 2019; 2:yty083. [PMID: 31020160 PMCID: PMC6177042 DOI: 10.1093/ehjcr/yty083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 07/06/2018] [Indexed: 01/28/2023]
Abstract
Background Andersen–Tawil syndrome (ATS) is a rare arrhythmia disorder caused by a mutation in the KCNJ2 gene. Typical presentation includes a triad of cardiac arrhythmia, dysmorphia, and periodic paralysis. However, KCNJ2 mutations can mimic other disorders such as catecholaminergic polymorphic ventricular tachycardia (CPVT) making treatment challenging. Case summary A 9-year-old asymptomatic female patient presented with an irregular heart rate noted at a well-child visit. Physical examination revealed short stature and facial dysmorphism. An initial rhythm strip showed intermittent runs of non-sustained bidirectional ventricular tachycardia with a prolonged QT interval of 485 ms at rest. Exercise testing showed no significant increase in ectopy from baseline at higher heart rates. Cardiac imaging was normal, and the burden of ventricular ectopy was significantly reduced on a beta-blocker and Class IC antiarrhythmic combination. Genetic testing marked a D71N mutation in the KCNJ2 gene. Discussion Clinical distinction between ATS and CPVT is a challenge. Genetic testing in the above patient attributed a likely pathogenic variant for both ATS and CPVT to a single D71N mutation in the KCNJ2 gene. Further evaluation revealed no clinical CPVT, emphasizing the need for cautious interpretation of genetic results in inherited arrhythmia disorders.
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Affiliation(s)
- Dustin Nguyen
- School of Medicine, Eastern Virginia Medical School, 825 Fairfax Ave, Norfolk, VA, USA
| | - Sunita J Ferns
- Department of Paediatrics, School of Medicine, University of North Carolina at Chapel Hill, 101 Manning Drive, Chapel Hill, NC, USA
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18
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Abstract
PURPOSE OF REVIEW Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a life-threatening syndrome defined by exercise-induced or emotion-induced ventricular arrhythmias, typically caused by gain-of-function mutations in RYR2-encoded ryanodine receptor-2 (RyR2). This review will discuss recent advances and ongoing challenges in devising genotype-specific CPVT therapies. RECENT FINDINGS CPVT patients were once universally thought to be at high risk of sudden death; however, as more cases emerge, CPVT is being re-defined as a complex syndrome of variable expressivity. Treatment was traditionally limited to β-blockers and implantable cardioverter defibrillators, and although β-blockers remain a mainstay of treatment, implantable cardioverter defibrillator use is associated with adverse events and should be limited. New applications for older therapies, like flecainide and cardiac denervation, appear to better target the mechanistic basis of CPVT arrhythmias. Recent advances in our understanding of RyR2 structure and function can help in identifying novel therapeutic targets. SUMMARY CPVT is usually related to RyR2 or associated proteins. Emerging studies reveal several genotype-phenotype correlations, which may eventually influence therapeutic decision-making. Flecainide has improved CPVT outcomes and will likely have broader clinical indications in the near future. Gene therapy has shown promise in animal models but has yet to be studied in humans. Sudden death can occur as a sentinel symptom, making preventive therapy that targets molecular mechanism(s) of arrhythmia a key area of ongoing investigation. VIDEO ABSTRACT.
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19
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Roston TM, Cunningham T, Lehman A, Laksman ZW, Krahn AD, Sanatani S. Beyond the Electrocardiogram: Mutations in Cardiac Ion Channel Genes Underlie Nonarrhythmic Phenotypes. Clin Med Insights Cardiol 2017; 11:1179546817698134. [PMID: 28469493 PMCID: PMC5392026 DOI: 10.1177/1179546817698134] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 02/01/2017] [Indexed: 12/19/2022]
Abstract
Cardiac ion channelopathies are an important cause of sudden death in the young and include long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, idiopathic ventricular fibrillation, and short QT syndrome. Genes that encode ion channels have been implicated in all of these conditions, leading to the widespread implementation of genetic testing for suspected channelopathies. Over the past half-century, researchers have also identified systemic pathologies that extend beyond the arrhythmic phenotype in patients with ion channel gene mutations, including deafness, epilepsy, cardiomyopathy, periodic paralysis, and congenital heart disease. A coexisting phenotype, such as cardiomyopathy, can influence evaluation and management. However, prior to recent molecular advances, our understanding and recognition of these overlapping phenotypes were poor. This review highlights the systemic and structural heart manifestations of the cardiac ion channelopathies, including their phenotypic spectrum and molecular basis.
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Affiliation(s)
- Thomas M Roston
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Taylor Cunningham
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Anna Lehman
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Zachary W Laksman
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Andrew D Krahn
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada
| | - Shubhayan Sanatani
- British Columbia Inherited Arrhythmia Program and University of British Columbia, Vancouver, BC, Canada.,Children's Heart Centre, BC Children's Hospital, Vancouver, BC, Canada
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20
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Van Ert HA, McCune EC, Orland KM, Maginot KR, Von Bergen NH, January CT, Eckhardt LL. Flecainide treats a novel KCNJ2 mutation associated with Andersen-Tawil syndrome. HeartRhythm Case Rep 2016; 3:151-154. [PMID: 28491792 PMCID: PMC5420046 DOI: 10.1016/j.hrcr.2016.11.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Hanora A Van Ert
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, Wisconsin
| | - Elise C McCune
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kate M Orland
- University of Wisconsin-Madison Inherited Arrhythmia Clinic, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kathleen R Maginot
- University of Wisconsin-Madison Inherited Arrhythmia Clinic, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Nicholas H Von Bergen
- University of Wisconsin-Madison Inherited Arrhythmia Clinic, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Craig T January
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, Wisconsin.,University of Wisconsin-Madison Inherited Arrhythmia Clinic, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Lee L Eckhardt
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, Wisconsin.,University of Wisconsin-Madison Inherited Arrhythmia Clinic, Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
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Manotheepan R, Danielsen TK, Sadredini M, Anderson ME, Carlson CR, Lehnart SE, Sjaastad I, Stokke MK. Exercise training prevents ventricular tachycardia in CPVT1 due to reduced CaMKII-dependent arrhythmogenic Ca2+ release. Cardiovasc Res 2016; 111:295-306. [PMID: 27161030 DOI: 10.1093/cvr/cvw095] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 05/01/2016] [Indexed: 01/05/2023] Open
Abstract
AIMS Catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) is caused by mutations in the cardiac ryanodine receptor (RyR2) that lead to disrupted Ca(2+) handling in cardiomyocytes and ventricular tachycardia. The aim of this study was to test whether exercise training could reduce the propensity for arrhythmias in mice with the CPVT1-causative missense mutation Ryr2-R2474S by restoring normal Ca(2+) handling. METHODS AND RESULTS Ryr2-R2474S mice (RyR-RS) performed a 2 week interval treadmill exercise training protocol. Each exercise session comprised five 8 min intervals at 80-90% of the running speed at maximal oxygen uptake (VO2max) and 2 min active rest periods at 60%. VO2max increased by 10 ± 2% in exercise trained RyR-RS (ET), while no changes were found in sedentary controls (SED). RyR-RS ET showed fewer episodes of ventricular tachycardia compared with RyR-RS SED, coinciding with fewer Ca(2+) sparks and waves, less diastolic Ca(2+) leak from the sarcoplasmic reticulum, and lower phosphorylation levels at RyR2 sites associated with Ca(2) (+)-calmodulin-dependent kinase type II (CaMKII) compared with RyR-RS SED. The CaMKII inhibitor autocamtide-2-related inhibitory peptide and also the antioxidant N-acetyl-l-cysteine reduced Ca(2+) wave frequency in RyR-RS equally to exercise training. Protein analysis as well as functional data indicated a mechanism depending on reduced levels of oxidized CaMKII after exercise training. Two weeks of detraining reversed the beneficial effects of the interval treadmill exercise training protocol in RyR-RS ET. CONCLUSION Long-term effects of interval treadmill exercise training reduce ventricular tachycardia episodes in mice with a CPVT1-causative Ryr2 mutation through lower CaMKII-dependent phosphorylation of RyR2.
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Affiliation(s)
- Ravinea Manotheepan
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Tore K Danielsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Mani Sadredini
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Mark E Anderson
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Cathrine R Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Stephan E Lehnart
- Clinic of Cardiology and Pulmonology, Heart Research Center Göttingen, Göttingen, Germany
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway
| | - Mathis K Stokke
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway Center for Heart Failure Research, University of Oslo, Oslo, Norway Clinic for Internal Medicine, Lovisenberg Diakonale Hospital, Oslo, Norway
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