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Peltenburg PJ, Gibson H, Wilde AAM, van der Werf C, Clur SAB, Blom NA. Prognosis and clinical management of asymptomatic family members with RYR2-mediated catecholaminergic polymorphic ventricular tachycardia: a review. Cardiol Young 2024:1-8. [PMID: 38653721 DOI: 10.1017/s1047951124000714] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Despite its low prevalence, the potential diagnosis of catecholaminergic polymorphic ventricular tachycardia (CPVT) should be at the forefront of a paediatric cardiologists mind in children with syncope during exercise or emotions. Over the years, the number of children with a genetic diagnosis of CPVT due to a (likely) pathogenic RYR2 variant early in life and prior to the onset of symptoms has increased due to cascade screening programmes. Limited guidance for this group of patients is currently available. Therefore, we aimed to summarise currently available literature for asymptomatic patients with a (likely) pathogenic RYR2 variant, particularly the history of CPVT and its genetic architecture, the currently available diagnostic tests and their limitations, and the development of a CPVT phenotype - both electrocardiographically and symptomatic - of affected family members. Their risk of arrhythmic events is presumably low and a phenotype seems to develop in the first two decades of life. Future research should focus on this group in particular, to better understand the development of a phenotype over time, and therefore, to be able to better guide clinical management - including the frequency of diagnostic tests, the timing of the initiation of drug therapy, and lifestyle recommendations.
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Affiliation(s)
- Puck J Peltenburg
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, UMC, University of Amsterdam, Heart Centre, Amsterdam, The Netherlands
- Department of Pediatric Cardiology, Amsterdam UMC, University of Amsterdam, Emma Children's Hospital, Amsterdam, The Netherlands
| | - Harry Gibson
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, UMC, University of Amsterdam, Heart Centre, Amsterdam, The Netherlands
| | - Arthur A M Wilde
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, UMC, University of Amsterdam, Heart Centre, Amsterdam, The Netherlands
| | - Christian van der Werf
- Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, UMC, University of Amsterdam, Heart Centre, Amsterdam, The Netherlands
| | - Sally-Ann B Clur
- Department of Pediatric Cardiology, Amsterdam UMC, University of Amsterdam, Emma Children's Hospital, Amsterdam, The Netherlands
| | - Nico A Blom
- Department of Pediatric Cardiology, Amsterdam UMC, University of Amsterdam, Emma Children's Hospital, Amsterdam, The Netherlands
- Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, Leiden University Medical Centre, Leiden, The Netherlands
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Bansal V, Winkelmann BR, Dietrich JW, Boehm BO. Whole-exome sequencing in familial type 2 diabetes identifies an atypical missense variant in the RyR2 gene. Front Endocrinol (Lausanne) 2024; 15:1258982. [PMID: 38444585 PMCID: PMC10913019 DOI: 10.3389/fendo.2024.1258982] [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] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 01/10/2024] [Indexed: 03/07/2024] Open
Abstract
Genome-wide association studies have identified several hundred loci associated with type 2 diabetes mellitus (T2DM). Additionally, pathogenic variants in several genes are known to cause monogenic diabetes that overlaps clinically with T2DM. Whole-exome sequencing of related individuals with T2DM is a powerful approach to identify novel high-penetrance disease variants in coding regions of the genome. We performed whole-exome sequencing on four related individuals with T2DM - including one individual diagnosed at the age of 33 years. The individuals were negative for mutations in monogenic diabetes genes, had a strong family history of T2DM, and presented with several characteristics of metabolic syndrome. A missense variant (p.N2291D) in the type 2 ryanodine receptor (RyR2) gene was one of eight rare coding variants shared by all individuals. The variant was absent in large population databases and affects a highly conserved amino acid located in a mutational hotspot for pathogenic variants in Catecholaminergic polymorphic ventricular tachycardia (CPVT). Electrocardiogram data did not reveal any cardiac abnormalities except a lower-than-normal resting heart rate (< 60 bpm) in two individuals - a phenotype observed in CPVT individuals with RyR2 mutations. RyR2-mediated Ca2+ release contributes to glucose-mediated insulin secretion and pathogenic RyR2 mutations cause glucose intolerance in humans and mice. Analysis of glucose tolerance testing data revealed that missense mutations in a CPVT mutation hotspot region - overlapping the p.N2291D variant - are associated with complete penetrance for glucose intolerance. In conclusion, we have identified an atypical missense variant in the RyR2 gene that co-segregates with diabetes in the absence of overt CPVT.
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Affiliation(s)
- Vikas Bansal
- Department of Pediatrics, University of California San Diego, La Jolla, CA, United States
- Institute of Genomic Medicine, University of California San Diego, La Jolla, CA, United States
| | | | - Johannes W Dietrich
- Diabetes, Endocrinology and Metabolism Section, Department of Internal Medicine I, St. Josef Hospital, Ruhr University Hospitals, Bochum, Germany
- Diabetes Center Bochum-Hattingen, St. Elisabeth-Hospital Blankenstein, Hattingen, Germany
- Center for Rare Endocrine Diseases, Ruhr Center for Rare Diseases (CeSER), Ruhr University Bochum and Witten/Herdecke University, Bochum, Germany
- Center for Diabetes Technology, Catholic Hospitals Bochum, Bochum, Germany
| | - Bernhard O Boehm
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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Askarinejad A, Esmaeili S, Dalili M, Biglari A, Kohansal E, Maleki M, Kalayinia S. Catecholaminergic polymorphic ventricular tachycardia (and seizure) caused by a novel homozygous likely pathogenic variant in CASQ2 gene. Gene 2024; 895:148012. [PMID: 37995796 DOI: 10.1016/j.gene.2023.148012] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/15/2023] [Indexed: 11/25/2023]
Abstract
BACKGROUND Although structural heart disease is frequently present among patients who experience sudden cardiac death (SCD), inherited arrhythmia syndromes can also play an important role in the occurrence of SCD. CPVT2, which is the second-most prevalent form of CPVT, arises from an abnormality in the CASQ2 gene. OBJECTIVE We represent a novel CASQ2 variant that causes CPVT2 and conduct a comprehensive review on this topic. METHODS The proband underwent Whole-exome sequencing (WES) in order to ascertain the etiology of CPVT. Subsequently, the process of segregating the available family members was carried out through the utilization of PCR and Sanger Sequencing. We searched the google scholar and PubMed/Medline for studies reporting CASQ2 variants, published up to May 10,2023. We used the following mesh term "Calsequestrin" and using free-text method with terms including "CASQ2","CASQ2 variants", and "CASQ2 mutation". RESULTS The CASQ2 gene was found to contain an autosomal recessive nonsense variant c.268_269insTA:p.Gly90ValfsTer4, which was identified by WES. This variant was determined to be the most probable cause of CPVT in the pedigree under investigation. CONCLUSION CASQ2 variants play an important role in pathogenesis of CPVT2. Notabely, based on results of our study and other findings in the literature the variant in this gene may cause an neurological signs in the patients with CPVT2. Further studies are needed for more details about the role of this gene in CPVT evaluation, diagnosis, and gene therapy.
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Affiliation(s)
- Amir Askarinejad
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Shiva Esmaeili
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Mohamad Dalili
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Alireza Biglari
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Erfan Kohansal
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Maleki
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Kalayinia
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
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Badura K, Buławska D, Dąbek B, Witkowska A, Lisińska W, Radzioch E, Skwira S, Młynarska E, Rysz J, Franczyk B. Primary Electrical Heart Disease-Principles of Pathophysiology and Genetics. Int J Mol Sci 2024; 25:1826. [PMID: 38339103 PMCID: PMC10855675 DOI: 10.3390/ijms25031826] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/27/2024] [Accepted: 01/28/2024] [Indexed: 02/12/2024] Open
Abstract
Primary electrical heart diseases, often considered channelopathies, are inherited genetic abnormalities of cardiomyocyte electrical behavior carrying the risk of malignant arrhythmias leading to sudden cardiac death (SCD). Approximately 54% of sudden, unexpected deaths in individuals under the age of 35 do not exhibit signs of structural heart disease during autopsy, suggesting the potential significance of channelopathies in this group of age. Channelopathies constitute a highly heterogenous group comprising various diseases such as long QT syndrome (LQTS), short QT syndrome (SQTS), idiopathic ventricular fibrillation (IVF), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and early repolarization syndromes (ERS). Although new advances in the diagnostic process of channelopathies have been made, the link between a disease and sudden cardiac death remains not fully explained. Evolving data in electrophysiology and genetic testing suggest previously described diseases as complex with multiple underlying genes and a high variety of factors associated with SCD in channelopathies. This review summarizes available, well-established information about channelopathy pathogenesis, genetic basics, and molecular aspects relative to principles of the pathophysiology of arrhythmia. In addition, general information about diagnostic approaches and management is presented. Analyzing principles of channelopathies and their underlying causes improves the understanding of genetic and molecular basics that may assist general research and improve SCD prevention.
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Affiliation(s)
- Krzysztof Badura
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Dominika Buławska
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Bartłomiej Dąbek
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Alicja Witkowska
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Wiktoria Lisińska
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Ewa Radzioch
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Sylwia Skwira
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Ewelina Młynarska
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
| | - Jacek Rysz
- Department of Nephrology, Hypertension and Family Medicine, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland
| | - Beata Franczyk
- Department of Nephrocardiology, Medical University of Lodz, Ul. Zeromskiego 113, 90-549 Lodz, Poland (S.S.)
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Bergeman AT, Robyns T, Amin AS, Wilde AAM, van der Werf C. Importance of exercise stress testing in evaluation of unexplained cardiac arrest survivor. Neth Heart J 2023; 31:444-451. [PMID: 37347419 PMCID: PMC10602994 DOI: 10.1007/s12471-023-01789-w] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND In sudden cardiac arrest survivors without an immediately identifiable cause, additional extensive yet individualised testing is required. METHODS We describe 3 survivors of sudden cardiac arrest in whom exercise stress testing was not performed during the initial hospital admission. RESULTS All 3 patients were incorrectly diagnosed with long QT syndrome based on temporary sudden cardiac arrest-related heart rate-corrected QT interval prolongation, and exercise stress testing was not performed during the initial work-up. When they were subjected to exercise stress testing during follow-up, a delayed diagnosis of catecholaminergic polymorphic ventricular tachycardia (CPVT) was made. As a result, these patients were initially managed inappropriately, and their family members were initially not screened for CPVT. CONCLUSION In sudden cardiac arrest survivors without an immediately identifiable cause, omission of exercise stress testing or erroneous interpretation of the results can lead to a delayed or missed diagnosis of CPVT, which may have considerable implications for survivors and their family.
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Affiliation(s)
- Auke T Bergeman
- Heart Centre, Department of Cardiology, Amsterdam University Medical Centres, location Academic Medical Centre, Amsterdam, The Netherlands
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (ERN GUARD-Heart), Brussels, Belgium
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, The Netherlands
| | - Tomas Robyns
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (ERN GUARD-Heart), Brussels, Belgium
- Department of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium
| | - Ahmad S Amin
- Heart Centre, Department of Cardiology, Amsterdam University Medical Centres, location Academic Medical Centre, Amsterdam, The Netherlands
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (ERN GUARD-Heart), Brussels, Belgium
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, The Netherlands
| | - Arthur A M Wilde
- Heart Centre, Department of Cardiology, Amsterdam University Medical Centres, location Academic Medical Centre, Amsterdam, The Netherlands
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (ERN GUARD-Heart), Brussels, Belgium
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, The Netherlands
| | - Christian van der Werf
- Heart Centre, Department of Cardiology, Amsterdam University Medical Centres, location Academic Medical Centre, Amsterdam, The Netherlands.
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (ERN GUARD-Heart), Brussels, Belgium.
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, The Netherlands.
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Ebrahim MA, Alkhabbaz AA, Albash B, AlSayegh AH, Webster G. Trans-2,3-enoyl-CoA reductase-like-related catecholaminergic polymorphic ventricular tachycardia with regular ventricular tachycardia and response to flecainide. J Cardiovasc Electrophysiol 2023; 34:1996-2001. [PMID: 37473425 DOI: 10.1111/jce.16011] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 06/23/2023] [Accepted: 07/10/2023] [Indexed: 07/22/2023]
Abstract
INTRODUCTION We describe a unique case of TECRL-CPVT presented with cardiac arrest. METHODS Post resuscitation, the patient developed regular ventricular tachycardia featuring a left purkinje system morphology. RESULTS There was clear suppression of arrhythmia with the addition of flecainide and isolated ventricular ectopy causing secondary T-wave changes. CONCLUSION A high index of suspicion was required to eventually make the diagnosis through whole exome sequencing.
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Affiliation(s)
- Mohammad A Ebrahim
- Department of Pediatrics, Affiliated with Chest Diseases Hospital, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | | | - Buthaina Albash
- Department of Genetics, Ghanima Al Ghanem Center, Ministry of Health, Kuwait City, Kuwait
| | - Ali H AlSayegh
- Department of Cardiology, Chest Diseases Hospital, Ministry of Health, Kuwait City, Kuwait
| | - Gregory Webster
- Division of Cardiology, Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Deb A, Tow BD, Qing Y, Walker M, Hodges ER, Stewart JA, Knollmann BC, Zheng Y, Wang Y, Liu B. Genetic Inhibition of Mitochondrial Permeability Transition Pore Exacerbates Ryanodine Receptor 2 Dysfunction in Arrhythmic Disease. Cells 2023; 12:204. [PMID: 36672139 PMCID: PMC9856515 DOI: 10.3390/cells12020204] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 01/06/2023] Open
Abstract
The brief opening mode of the mitochondrial permeability transition pore (mPTP) serves as a calcium (Ca2+) release valve to prevent mitochondrial Ca2+ (mCa2+) overload. Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a stress-induced arrhythmic syndrome due to mutations in the Ca2+ release channel complex of ryanodine receptor 2 (RyR2). We hypothesize that inhibiting the mPTP opening in CPVT exacerbates the disease phenotype. By crossbreeding a CPVT model of CASQ2 knockout (KO) with a mouse missing CypD, an activator of mPTP, a double KO model (DKO) was generated. Echocardiography, cardiac histology, and live-cell imaging were employed to assess the severity of cardiac pathology. Western blot and RNAseq were performed to evaluate the contribution of various signaling pathways. Although exacerbated arrhythmias were reported, the DKO model did not exhibit pathological remodeling. Myocyte Ca2+ handling was similar to that of the CASQ2 KO mouse at a low pacing frequency. However, increased ROS production, activation of the CaMKII pathway, and hyperphosphorylation of RyR2 were detected in DKO. Transcriptome analysis identified altered gene expression profiles associated with electrical instability in DKO. Our study provides evidence that genetic inhibition of mPTP exacerbates RyR2 dysfunction in CPVT by increasing activation of the CaMKII pathway and subsequent hyperphosphorylation of RyR2.
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Affiliation(s)
- Arpita Deb
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Brian D. Tow
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - You Qing
- Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Bioinformatics Center, Beijing University of Agriculture, Beijing 102206, China
| | - Madelyn Walker
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Emmanuel R. Hodges
- School of Pharmacy, Division of BioMolecular Sciences, University of Mississippi, Oxford, MS 38677, USA
| | - James A. Stewart
- School of Pharmacy, Division of BioMolecular Sciences, University of Mississippi, Oxford, MS 38677, USA
| | - Björn C. Knollmann
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yi Zheng
- Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Bioinformatics Center, Beijing University of Agriculture, Beijing 102206, China
| | - Ying Wang
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Bin Liu
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
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McCoy MD, Ullah A, Lederer WJ, Jafri MS. Understanding Calmodulin Variants Affecting Calcium-Dependent Inactivation of L-Type Calcium Channels through Whole-Cell Simulation of the Cardiac Ventricular Myocyte. Biomolecules 2022; 13:72. [PMID: 36671457 PMCID: PMC9855640 DOI: 10.3390/biom13010072] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 12/31/2022] Open
Abstract
Mutations in the calcium-sensing protein calmodulin (CaM) have been linked to two cardiac arrhythmia diseases, Long QT Syndrome 14 (LQT14) and Catecholaminergic Polymorphic Ventricular Tachycardia Type 4 (CPVT4), with varying degrees of severity. Functional characterization of the CaM mutants most strongly associated with LQT14 show a clear disruption of the calcium-dependent inactivation (CDI) of the L-Type calcium channel (LCC). CPVT4 mutants on the other hand are associated with changes in their affinity to the ryanodine receptor. In clinical studies, some variants have been associated with both CPVT4 and LQT15. This study uses simulations in a model for excitation-contraction coupling in the rat ventricular myocytes to understand how LQT14 variant might give the functional phenotype similar to CPVT4. Changing the CaM-dependent transition rate by a factor of 0.75 corresponding to the D96V variant and by a factor of 0.90 corresponding to the F142L or N98S variants, in a physiologically based stochastic model of the LCC prolonger, the action potential duration changed by a small amount in a cardiac myocyte but did not disrupt CICR at 1, 2, and 4 Hz. Under beta-adrenergic simulation abnormal excitation-contraction coupling was observed above 2 Hz pacing for the mutant CaM. The same conditions applied under beta-adrenergic stimulation led to the rapid onset of arrhythmia in the mutant CaM simulations. Simulations with the LQT14 mutations under the conditions of rapid pacing with beta-adrenergic stimulation drives the cardiac myocyte toward an arrhythmic state known as Ca2+ overload. These simulations provide a mechanistic link to a disease state for LQT14-associated mutations in CaM to yield a CPVT4 phenotype. The results show that small changes to the CaM-regulated inactivation of LCC promote arrhythmia and underscore the significance of CDI in proper heart function.
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Affiliation(s)
- Matthew D. McCoy
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
- Innovation Center for Biomedical Informatics, Department of Oncology, Georgetown University Medical Center, Georgetown University, Washington, DC 20057, USA
| | - Aman Ullah
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
| | - W. Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 20201, USA
| | - M. Saleet Jafri
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 20201, USA
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Tow BD, Deb A, Neupane S, Patel SM, Reed M, Loper AB, Eliseev RA, Knollmann BC, Györke S, Liu B. SR-Mitochondria Crosstalk Shapes Ca Signalling to Impact Pathophenotype in Disease Models Marked by Dysregulated Intracellular Ca Release. Cardiovasc Res 2022; 118:2819-2832. [PMID: 34677619 PMCID: PMC9724772 DOI: 10.1093/cvr/cvab324] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 04/09/2021] [Accepted: 10/12/2021] [Indexed: 12/29/2022] Open
Abstract
AIMS Diastolic Ca release (DCR) from sarcoplasmic reticulum (SR) Ca release channel ryanodine receptor (RyR2) has been linked to multiple cardiac pathologies, but its exact role in shaping divergent cardiac pathologies remains unclear. We hypothesize that the SR-mitochondria interplay contributes to disease phenotypes by shaping Ca signalling. METHODS AND RESULTS A genetic model of catecholaminergic polymorphic ventricular tachycardia (CPVT2 model of CASQ2 knockout) and a pre-diabetic cardiomyopathy model of fructose-fed mice (FFD), both marked by DCR, are employed in this study. Mitochondria Ca (mCa) is modulated by pharmacologically targeting mitochondria Ca uniporter (MCU) or permeability transition pore (mPTP), mCa uptake, and extrusion mechanisms, respectively. An MCU activator abolished Ca waves in CPVT2 but exacerbated waves in FFD cells. Mechanistically this is ascribed to mitochondria's function as a Ca buffer or source of reactive oxygen species (mtROS) to exacerbate RyR2 functionality, respectively. Enhancing mCa uptake reduced and elevated mtROS production in CPVT2 and FFD, respectively. In CPVT2, mitochondria took up more Ca in permeabilized cells, and had higher level of mCa content in intact cells vs. FFD. Conditional ablation of MCU in the CPVT2 model caused lethality and cardiac remodelling, but reduced arrhythmias in the FFD model. In parallel, CPVT2 mitochondria also employ up-regulated mPTP-mediated Ca efflux to avoid mCa overload, as seen by elevated incidence of MitoWinks (an indicator of mPTP-mediated Ca efflux) vs. FFD. Both pharmacological and genetic inhibition of mPTP promoted mtROS production and exacerbation of myocyte Ca handling in CPVT2. Further, genetic inhibition of mPTP exacerbated arrhythmias in CPVT2. CONCLUSION In contrast to FFD, which is more susceptible to mtROS-dependent RyR2 leak, in CPVT2 mitochondria buffer SR-derived DCR to mitigate Ca-dependent pathological remodelling and rely on mPTP-mediated Ca efflux to avoid mCa overload. SR-mitochondria interplay contributes to the divergent pathologies by disparately shaping intracellular Ca signalling.
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Affiliation(s)
- Brian D Tow
- Department of Biological Sciences, Mississippi State University, 295 Lee Blvd, Starkville, Mississippi, 39762, USA
| | - Arpita Deb
- Department of Biological Sciences, Mississippi State University, 295 Lee Blvd, Starkville, Mississippi, 39762, USA
| | - Shraddha Neupane
- Department of Biological Sciences, Mississippi State University, 295 Lee Blvd, Starkville, Mississippi, 39762, USA
| | - Shuchi M Patel
- Department of Biological Sciences, Mississippi State University, 295 Lee Blvd, Starkville, Mississippi, 39762, USA
| | - Meagan Reed
- Department of Biological Sciences, Mississippi State University, 295 Lee Blvd, Starkville, Mississippi, 39762, USA
| | - Anna-Beth Loper
- Department of Biological Sciences, Mississippi State University, 295 Lee Blvd, Starkville, Mississippi, 39762, USA
| | - Roman A Eliseev
- epartment of Orthopedics, Center for Musculoskeletal Research, University of Rochester, 601 Elmwood Ave, Rochester, New York 14624, USA
| | - Björn C Knollmann
- Department of Medicine, Vanderbilt University School of Medicine, 2215B Garland Ave, Nashville, Tennessee, 37232, USA
| | - Sándor Györke
- Davis Heart and Lung Research Institute and Department of Physiology and Cell Biology, The Ohio State University, 473 W. 12th Avenue, Columbus, Ohio 43210, USA
| | - Bin Liu
- Department of Biological Sciences, Mississippi State University, 295 Lee Blvd, Starkville, Mississippi, 39762, USA
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Leung J, Lee S, Zhou J, Jeevaratnam K, Lakhani I, Radford D, Coakley-Youngs E, Pay L, Çinier G, Altinsoy M, Behnoush AH, Mahmoudi E, Matusik PT, Bazoukis G, Garcia-Zamora S, Zeng S, Chen Z, Xia Y, Liu T, Tse G. Clinical Characteristics, Genetic Findings and Arrhythmic Outcomes of Patients with Catecholaminergic Polymorphic Ventricular Tachycardia from China: A Systematic Review. Life (Basel) 2022; 12:life12081104. [PMID: 35892906 PMCID: PMC9330865 DOI: 10.3390/life12081104] [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] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/12/2022] [Accepted: 07/19/2022] [Indexed: 11/16/2022]
Abstract
INTRODUCTION Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited cardiac ion channelopathy. The present study aims to examine the clinical characteristics, genetic basis, and arrhythmic outcomes of CPVT patients from China to elucidate the difference between CPVT patients in Asia and Western countries. METHODS PubMed and Embase were systematically searched for case reports or series reporting on CPVT patients from China until 19 February 2022 using the keyword: "Catecholaminergic Polymorphic Ventricular Tachycardia" or "CPVT", with the location limited to: "China" or "Hong Kong" or "Macau" in Embase, with no language or publication-type restriction. Articles that did not state a definite diagnosis of CPVT and articles with duplicate cases found in larger cohorts were excluded. All the included publications in this review were critically appraised based on the Joanna Briggs Institute Critical Appraisal Checklist. Clinical characteristics, genetic findings, and the primary outcome of spontaneous ventricular tachycardia/ventricular fibrillation (VT/VF) were analyzed. RESULTS A total of 58 unique cases from 15 studies (median presentation age: 8 (5.0-11.8) years old) were included. All patients, except one, presented at or before 19 years of age. There were 56 patients (96.6%) who were initially symptomatic. Premature ventricular complexes (PVCs) were present in 44 out of 51 patients (86.3%) and VT in 52 out of 58 patients (89.7%). Genetic tests were performed on 54 patients (93.1%) with a yield of 87%. RyR2, CASQ2, TERCL, and SCN10A mutations were found in 35 (71.4%), 12 (24.5%), 1 (0.02%) patient, and 1 patient (0.02%), respectively. There were 54 patients who were treated with beta-blockers, 8 received flecainide, 5 received amiodarone, 2 received verapamil and 2 received propafenone. Sympathectomy (n = 10), implantable cardioverter-defibrillator implantation (n = 8) and ablation (n = 1) were performed. On follow-up, 13 patients developed VT/VF. CONCLUSION This was the first systematic review of CPVT patients from China. Most patients had symptoms on initial presentation, with syncope as the presenting complaint. RyR2 mutation accounts for more than half of the CPVT cases, followed by CASQ2, TERCL and SCN10A mutations.
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Affiliation(s)
- Justin Leung
- Cardiac Electrophysiology Unit, Cardiovascular Analytics Group, China-UK Collaboration, Hong Kong, China; (J.L.); (S.L.); (I.L.)
| | - Sharen Lee
- Cardiac Electrophysiology Unit, Cardiovascular Analytics Group, China-UK Collaboration, Hong Kong, China; (J.L.); (S.L.); (I.L.)
| | - Jiandong Zhou
- School of Data Science, City University of Hong Kong, Hong Kong, China;
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK;
| | - Ishan Lakhani
- Cardiac Electrophysiology Unit, Cardiovascular Analytics Group, China-UK Collaboration, Hong Kong, China; (J.L.); (S.L.); (I.L.)
| | - Danny Radford
- Kent and Medway Medical School, Canterbury CT2 7FS, UK; (D.R.); (E.C.-Y.)
| | | | - Levent Pay
- Department of Cardiology, Dr Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul 34147, Turkey; (L.P.); (G.Ç.)
| | - Göksel Çinier
- Department of Cardiology, Dr Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital, Istanbul 34147, Turkey; (L.P.); (G.Ç.)
| | - Meltem Altinsoy
- Department of Cardiology, University of Health Sciences, Diskapi Yildirim Beyazit Training and Research Hospital, Ankara 06145, Turkey;
| | - Amir Hossein Behnoush
- Universal Scientific Education and Research Network (USERN), Tehran University of Medical Sciences, Tehran 1416643931, Iran; (A.H.B.); (E.M.)
| | - Elham Mahmoudi
- Universal Scientific Education and Research Network (USERN), Tehran University of Medical Sciences, Tehran 1416643931, Iran; (A.H.B.); (E.M.)
| | - Paweł T. Matusik
- Department of Electrocardiology, Institute of Cardiology, Jagiellonian University Medical College, John Paul II Hospital, 31-202 Kraków, Poland;
| | - George Bazoukis
- Department of Cardiology, Larnaca General Hospital, Larnaca 6301, Cyprus;
- Medical School, University of Nicosia, Nicosia 2408, Cyprus
| | - Sebastian Garcia-Zamora
- Cardiac Intensive Care Unit, Department of Cardiology, Delta Clinic, Rosario S2000, Argentina;
| | - Shaoying Zeng
- Department of Pediatric Cardiology, Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China;
| | - Ziliang Chen
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China;
| | - Yunlong Xia
- Department of Cardiology, First Affiliated Hospital of Dalian Medical University, Dalian 116014, China;
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China;
- Correspondence: (T.L.); or or (G.T.)
| | - Gary Tse
- Cardiac Electrophysiology Unit, Cardiovascular Analytics Group, China-UK Collaboration, Hong Kong, China; (J.L.); (S.L.); (I.L.)
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK;
- Kent and Medway Medical School, Canterbury CT2 7FS, UK; (D.R.); (E.C.-Y.)
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China;
- Department of Cardiology, First Affiliated Hospital of Dalian Medical University, Dalian 116014, China;
- Correspondence: (T.L.); or or (G.T.)
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11
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Mareddy C, ScM MT, McDaniel G, Monfredi O. Exercise in the Genetic Arrhythmia Syndromes - A Review. Clin Sports Med 2022; 41:485-510. [PMID: 35710274 DOI: 10.1016/j.csm.2022.02.008] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Provide a brief summary of your article (100-150 words; no references or figures/tables). The synopsis appears only in the table of contents and is often used by indexing services such as PubMed. Genetic arrhythmia syndromes are rare, yet harbor the potential for highly consequential, often unpredictable arrhythmias or sudden death events. There has been historical uncertainty regarding the correct advice to offer to affected patients who are reasonably wanting to participate in sporting and athletic endeavors. In some cases, this had led to abundantly cautious disqualifications, depriving individuals from participation unnecessarily. Societal guidance and expert opinion has evolved significantly over the last decade or 2, along with our understanding of the genetics and natural history of these conditions, and the emphasis has switched toward shared decision making with respect to the decision to participate or not, with patients and families becoming better informed, and willing participants in the decision making process. This review aims to give a brief update of the salient issues for the busy physician concerning these syndromes and to provide a framework for approaching their management in the otherwise aspirational or keen sports participant.
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Affiliation(s)
- Chinmaya Mareddy
- Division of Cardiovascular Medicine, Department of Medicine, University of Virginia, 1215 Lee St, Charlottesville, VA 22908, USA
| | - Matthew Thomas ScM
- Department of Pediatrics, P.O. Box 800386, Charlottesville, VA 22908, USA
| | - George McDaniel
- Department of Pediatric Cardiology, Battle Building 6th Floor, 1204 W. Main St, Charlottesville, VA 22903, USA
| | - Oliver Monfredi
- Division of Cardiovascular Medicine, Department of Medicine, University of Virginia, 1215 Lee St, Charlottesville, VA 22908, USA.
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12
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Szentandrássy N, Magyar ZÉ, Hevesi J, Bányász T, Nánási PP, Almássy J. Therapeutic Approaches of Ryanodine Receptor-Associated Heart Diseases. Int J Mol Sci 2022; 23:4435. [PMID: 35457253 DOI: 10.3390/ijms23084435] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 01/08/2023] Open
Abstract
Cardiac diseases are the leading causes of death, with a growing number of cases worldwide, posing a challenge for both healthcare and research. Therefore, the most relevant aim of cardiac research is to unravel the molecular pathomechanisms and identify new therapeutic targets. Cardiac ryanodine receptor (RyR2), the Ca2+ release channel of the sarcoplasmic reticulum, is believed to be a good therapeutic target in a group of certain heart diseases, collectively called cardiac ryanopathies. Ryanopathies are associated with the impaired function of the RyR, leading to heart diseases such as congestive heart failure (CHF), catecholaminergic polymorphic ventricular tachycardia (CPVT), arrhythmogenic right ventricular dysplasia type 2 (ARVD2), and calcium release deficiency syndrome (CRDS). The aim of the current review is to provide a short insight into the pathological mechanisms of ryanopathies and discuss the pharmacological approaches targeting RyR2.
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13
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Hopton C, Tijsen AJ, Maizels L, Arbel G, Gepstein A, Bates N, Brown B, Huber I, Kimber SJ, Newman WG, Venetucci L, Gepstein L. Characterization of the mechanism by which a nonsense variant in RYR2 leads to disordered calcium handling. Physiol Rep 2022; 10:e15265. [PMID: 35439358 PMCID: PMC9017975 DOI: 10.14814/phy2.15265] [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] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/19/2022] [Accepted: 03/25/2022] [Indexed: 06/14/2023] Open
Abstract
Heterozygous missense variants of the cardiac ryanodine receptor gene (RYR2) cause catecholaminergic polymorphic ventricular tachycardia (CPVT). These missense variants of RYR2 result in a gain of function of the ryanodine receptors, characterized by increased sensitivity to activation by calcium that results in an increased propensity to develop calcium waves and delayed afterdepolarizations. We have recently detected a nonsense variant in RYR2 in a young patient who suffered an unexplained cardiac arrest. To understand the mechanism by which this variant in RYR2, p.(Arg4790Ter), leads to ventricular arrhythmias, human induced pluripotent stem cells (hiPSCs) harboring the novel nonsense variant in RYR2 were generated and differentiated into cardiomyocytes (RYR2-hiPSC-CMs) and molecular and calcium handling properties were studied. RYR2-hiPSC-CMs displayed significant calcium handling abnormalities at baseline and following treatment with isoproterenol. Treatment with carvedilol and nebivolol resulted in a significant reduction in calcium handling abnormalities in the RYR2-hiPSC-CMs. Expression of the mutant RYR2 allele was confirmed at the mRNA level and partial silencing of the mutant allele resulted in a reduction in calcium handling abnormalities at baseline. The nonsense variant behaves similarly to other gain of function variants in RYR2. Carvedilol and nebivolol may be suitable treatments for patients with gain of function RYR2 variants.
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Affiliation(s)
- Claire Hopton
- Division of Evolution and Genomic SciencesFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- Manchester Centre for Genomic MedicineManchester University NHS Foundation TrustHealth Innovation ManchesterManchesterUK
- Division of Cardiovascular SciencesFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Anke J. Tijsen
- The Rappaport Faculty of Medicine and Research InstituteTechnion‐Institute of TechnologyHaifaIsrael
- Amsterdam UMCDepartment of Experimental CardiologyAmsterdam Cardiovascular SciencesUniversity of AmsterdamAmsterdamThe Netherlands
| | - Leonid Maizels
- The Rappaport Faculty of Medicine and Research InstituteTechnion‐Institute of TechnologyHaifaIsrael
- Division of CardiologySheba Medical Center HospitalTel HashomerIsrael
- The Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
- The Talpiot Sheba Medical Leadership ProgramIsrael
| | - Gil Arbel
- The Rappaport Faculty of Medicine and Research InstituteTechnion‐Institute of TechnologyHaifaIsrael
| | - Amira Gepstein
- The Rappaport Faculty of Medicine and Research InstituteTechnion‐Institute of TechnologyHaifaIsrael
| | - Nicola Bates
- Division of Cell Matrix Biology and Regenerative MedicineFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Benjamin Brown
- Department of CardiologyWythenshawe HospitalManchester University NHS Foundation TrustManchesterUK
| | - Irit Huber
- The Rappaport Faculty of Medicine and Research InstituteTechnion‐Institute of TechnologyHaifaIsrael
| | - Susan J. Kimber
- Division of Cell Matrix Biology and Regenerative MedicineFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - William G. Newman
- Division of Evolution and Genomic SciencesFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- Manchester Centre for Genomic MedicineManchester University NHS Foundation TrustHealth Innovation ManchesterManchesterUK
| | - Luigi Venetucci
- Division of Cardiovascular SciencesFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- Manchester Heart CentreManchester University NHS Foundation TrustHealth Innovation ManchesterManchesterUK
| | - Lior Gepstein
- The Rappaport Faculty of Medicine and Research InstituteTechnion‐Institute of TechnologyHaifaIsrael
- Cardiology DepartmentRambam Health Care CampusHaifaIsrael
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14
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Prakash O, Held M, McCormick LF, Gupta N, Lian LY, Antonyuk S, Haynes LP, Thomas NL, Helassa N. CPVT-associated calmodulin variants N53I and A102V dysregulate Ca2+ signalling via different mechanisms. J Cell Sci 2022; 135:274029. [PMID: 34888671 PMCID: PMC8917356 DOI: 10.1242/jcs.258796] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 11/29/2021] [Indexed: 12/26/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited condition that can cause fatal cardiac arrhythmia. Human mutations in the Ca2+ sensor calmodulin (CaM) have been associated with CPVT susceptibility, suggesting that CaM dysfunction is a key driver of the disease. However, the detailed molecular mechanism remains unclear. Focusing on the interaction with the cardiac ryanodine receptor (RyR2), we determined the effect of CPVT-associated variants N53I and A102V on the structural characteristics of CaM and on Ca2+ fluxes in live cells. We provide novel data showing that interaction of both Ca2+/CaM-N53I and Ca2+/CaM-A102V with the RyR2 binding domain is decreased. Ca2+/CaM-RyR23583-3603 high-resolution crystal structures highlight subtle conformational changes for the N53I variant, with A102V being similar to wild type (WT). We show that co-expression of CaM-N53I or CaM-A102V with RyR2 in HEK293 cells significantly increased the duration of Ca2+ events; CaM-A102V exhibited a lower frequency of Ca2+ oscillations. In addition, we show that CaMKIIδ (also known as CAMK2D) phosphorylation activity is increased for A102V, compared to CaM-WT. This paper provides novel insight into the molecular mechanisms of CPVT-associated CaM variants and will facilitate the development of strategies for future therapies.
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Affiliation(s)
- Ohm Prakash
- Liverpool Centre for Cardiovascular Science, Department of Cardiovascular Science and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Marie Held
- Liverpool Centre for Cardiovascular Science, Department of Cardiovascular Science and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Liam F. McCormick
- Liverpool Centre for Cardiovascular Science, Department of Cardiovascular Science and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Nitika Gupta
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Lu-Yun Lian
- Nuclear Magnetic Resonance Centre for Structural Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Svetlana Antonyuk
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Lee P. Haynes
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - N. Lowri Thomas
- School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, Redwood Building, CF10 3NB, UK
| | - Nordine Helassa
- Liverpool Centre for Cardiovascular Science, Department of Cardiovascular Science and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK,Author for correspondence ()
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15
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Sadredini M, Manotheepan R, Lehnart SE, Anderson ME, Sjaastad I, Stokke MK. The oxidation-resistant CaMKII-MM281/282VV mutation does not prevent arrhythmias in CPVT1. Physiol Rep 2021; 9:e15030. [PMID: 34558218 PMCID: PMC8461029 DOI: 10.14814/phy2.15030] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/11/2021] [Accepted: 08/16/2021] [Indexed: 11/24/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) is an inherited arrhythmogenic disorder caused by missense mutations in the cardiac ryanodine receptors (RyR2), that result in increased β-adrenoceptor stimulation-induced diastolic Ca2+ leak. We have previously shown that exercise training prevents arrhythmias in CPVT1, potentially by reducing the oxidation of Ca2+ /calmodulin-dependent protein kinase type II (CaMKII). Therefore, we tested whether an oxidation-resistant form of CaMKII protects mice carrying the CPVT1-causative mutation RyR2-R2474S (RyR2-RS) against arrhythmias. Antioxidant treatment (N-acetyl-L-cysteine) reduced the frequency of β-adrenoceptor stimulation-induced arrhythmogenic Ca2+ waves in isolated cardiomyocytes from RyR2-RS mice. To test whether the prevention of CaMKII oxidation exerts an antiarrhythmic effect, mice expressing the oxidation-resistant CaMKII-MM281/282VV variant (MMVV) were crossed with RyR2-RS mice to create a double transgenic model (RyR2-RS/MMVV). Wild-type mice served as controls. Telemetric ECG surveillance revealed an increased incidence of ventricular tachycardia and an increased arrhythmia score in both RyR2-RS and RyR2-RS/MMVV compared to wild-type mice, both following a β-adrenoceptor challenge (isoprenaline i.p.), and following treadmill exercise combined with a β-adrenoceptor challenge. There were no differences in the incidence of arrhythmias between RyR2-RS and RyR2-RS/MMVV mice. Furthermore, no differences were observed in β-adrenoceptor stimulation-induced Ca2+ waves in RyR2-RS/MMVV compared to RyR2-RS. In conclusion, antioxidant treatment reduces β-adrenoceptor stimulation-induced Ca2+ waves in RyR2-RS cardiomyocytes. However, oxidation-resistant CaMKII-MM281/282VV does not protect RyR2-RS mice from β-adrenoceptor stimulation-induced Ca2+ waves or arrhythmias. Hence, alternative oxidation-sensitive targets need to be considered to explain the beneficial effect of antioxidant treatment on Ca2+ waves in cardiomyocytes from RyR2-RS mice.
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Affiliation(s)
- Mani Sadredini
- Institute for Experimental Medical Research and KG Jebsen Cardiac Research CentreOslo University Hospital and University of OsloOsloNorway
| | - Ravinea Manotheepan
- Institute for Experimental Medical Research and KG Jebsen Cardiac Research CentreOslo University Hospital and University of OsloOsloNorway
| | - Stephan E. Lehnart
- Heart Research Center GöttingenDepartment of Cardiology and PulmonologyUniversity Medical Center GöttingenGeorg August University GöttingenGöttingenGermany
- Cluster of Excellence “Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells” (MBExC)University of GöttingenGöttingenGermany
- DZHK (German Centre for Cardiovascular Research)GöttingenGermany
| | - Mark E. Anderson
- Division of CardiologyDepartment of MedicineThe Johns Hopkins University School of MedicineBaltimoreUSA
| | - Ivar Sjaastad
- Institute for Experimental Medical Research and KG Jebsen Cardiac Research CentreOslo University Hospital and University of OsloOsloNorway
| | - Mathis K. Stokke
- Institute for Experimental Medical Research and KG Jebsen Cardiac Research CentreOslo University Hospital and University of OsloOsloNorway
- Department of CardiologyOslo University HospitalRikshospitaletOsloNorway
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16
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Rabbani B, Khorgami M, Dalili M, Zamani N, Mahdieh N, Gollob MH. Novel cases of pediatric sudden cardiac death secondary to TRDN mutations presenting as long QT syndrome at rest and catecholaminergic polymorphic ventricular tachycardia during exercise: The TRDN arrhythmia syndrome. Am J Med Genet A 2021; 185:3433-3445. [PMID: 34415104 DOI: 10.1002/ajmg.a.62464] [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] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 07/15/2021] [Accepted: 07/22/2021] [Indexed: 12/15/2022]
Abstract
TRDN mutations cause catecholaminergic polymorphic ventricular tachycardia (CPVT) but may present with abnormal electrocardiogram (ECG) findings provoking a diagnosis of long QT syndrome (LQTS). We report two novel cases of sudden cardiac death in children due to mutations of TRDN, providing further insight into this rare and aggressive inherited arrhythmia syndrome. Whole exome sequencing (WES) was performed in two unrelated children who experienced cardiac arrest during exercise and were negative for targeted testing of LQTS. WES identified a novel homozygous splice-site mutation in both patients, denoted c.22+1G>T, absent from gnomAD and suggesting a founder variant in the Iranian population. We now summarize the genetic architecture of all reported TRDN-related patients, including 27 patients from 21 families. The average age-onset was 30 months (range 1-10) for all cases. Adrenergic-mediated cardiac events were common, occurring in 23 of 27 cases (85%). LQTS was diagnosed in 10 cases (37%), CPVT in 10 (37%) cases, and in 7 cases. No phenotypic diagnosis was provided. Five cases (15%) had evidence for associated skeletal myopathy. Four missense TRDN variants (24%) were observed in diseased cases, while the remaining variants reflect putative loss-of-function (LOF) mutations. No disease phenotype was reported in 26 heterozygous carriers. In conclusion, TRDN mutations cause a rare autosomal recessive arrhythmia syndrome presenting with adrenergic-mediated arrhythmic events, but with ECG abnormalities leading to a diagnosis of LQTS in a proportion of cases. Heterozygous carriers are free of disease manifestations.
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Affiliation(s)
- Bahareh Rabbani
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammadrafi Khorgami
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Dalili
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Nasrin Zamani
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Nejat Mahdieh
- Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran.,Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Michael H Gollob
- Inherited Arrhythmia and Cardiomyopathy Program, Arrhythmia Service, Division of Cardiology, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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17
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Sander P, Feng M, Schweitzer MK, Wilting F, Gutenthaler SM, Arduino DM, Fischbach S, Dreizehnter L, Moretti A, Gudermann T, Perocchi F, Schredelseker J. Approved drugs ezetimibe and disulfiram enhance mitochondrial Ca 2+ uptake and suppress cardiac arrhythmogenesis. Br J Pharmacol 2021; 178:4518-4532. [PMID: 34287836 DOI: 10.1111/bph.15630] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 11/26/2020] [Revised: 06/21/2021] [Accepted: 06/30/2021] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Treatment of cardiac arrhythmia remains challenging due to severe side effects of common anti-arrhythmic drugs. We previously demonstrated that mitochondrial Ca2+ uptake in cardiomyocytes represents a promising new candidate structure for safer drug therapy. However, druggable agonists of mitochondrial Ca2+ uptake suitable for preclinical and clinical studies are still missing. EXPERIMENTAL APPROACH Herewe screened 727 compounds with a history of use in human clinical trials in a three-step screening approach. As a primary screening platform we used a permeabilized HeLa cell-based mitochondrial Ca2+ uptake assay. Hits were validated in cultured HL-1 cardiomyocytes and finally tested for anti-arrhythmic efficacy in three translational models: a Ca2+ overload zebrafish model and cardiomyocytes of both a mouse model for catecholaminergic polymorphic ventricular tachycardia (CPVT) and induced pluripotent stem cell derived cardiomyocytes from a CPVT patient. KEY RESULTS We identifiedtwo candidate compounds, the clinically approved drugs ezetimibe and disulfiram, which stimulate SR-mitochondria Ca2+ transfer at nanomolar concentrations. This is significantly lower compared to the previously described mitochondrial Ca2+ uptake enhancers (MiCUps) efsevin, a gating modifier of the voltage-dependent anion channel 2, and kaempferol, an agonist of the mitochondrial Ca2+ uniporter. Both substances restored rhythmic cardiac contractions in a zebrafish cardiac arrhythmia model and significantly suppressed arrhythmogenesis in freshly isolated ventricular cardiomyocytes from a CPVT mouse model as well as induced pluripotent stem cell derived cardiomyocytes from a CPVT patient. CONCLUSION AND IMPLICATIONS Taken together we identified ezetimibe and disulfiram as novel MiCUps and efficient suppressors of arrhythmogenesis and as such as, promising candidates for future preclinical and clinical studies.
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Affiliation(s)
- Paulina Sander
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Michael Feng
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München, Neuherberg, Germany
| | - Maria K Schweitzer
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Fabiola Wilting
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Sophie M Gutenthaler
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Daniela M Arduino
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München, Neuherberg, Germany
| | - Sandra Fischbach
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Lisa Dreizehnter
- I. Department of Medicine, Cardiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Alessandra Moretti
- I. Department of Medicine, Cardiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.,Partner Site Munich Heart Alliance (MHA), Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK), Munich, Germany
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany.,Partner Site Munich Heart Alliance (MHA), Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK), Munich, Germany
| | - Fabiana Perocchi
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center (HDC), Helmholtz Zentrum München, Neuherberg, Germany.,Munich Cluster for Systems Neurology, Munich, Germany
| | - Johann Schredelseker
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany.,Partner Site Munich Heart Alliance (MHA), Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK), Munich, Germany
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Blancard M, Touat-Hamici Z, Aguilar-Sanchez Y, Yin L, Vaksmann G, Roux-Buisson N, Fressart V, Denjoy I, Klug D, Neyroud N, Ramos-Franco J, Gomez AM, Guicheney P. A Type 2 Ryanodine Receptor Variant in the Helical Domain 2 Associated with an Impairment of the Adrenergic Response. J Pers Med 2021; 11:jpm11060579. [PMID: 34202968 PMCID: PMC8235491 DOI: 10.3390/jpm11060579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 05/06/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 11/17/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is triggered by exercise or acute emotion in patients with normal resting electrocardiogram. The major disease-causing gene is RYR2, encoding the cardiac ryanodine receptor (RyR2). We report a novel RYR2 variant, p.Asp3291Val, outside the four CPVT mutation hotspots, in three CPVT families with numerous sudden deaths. This missense variant was first identified in a four-generation family, where eight sudden cardiac deaths occurred before the age of 30 in the context of adrenergic stress. All affected subjects harbored at least one copy of the RYR2 variant. Three affected sisters were homozygous for the variant. The same variant was found in two additional CPVT families. It is located in the helical domain 2 and changes a negatively charged amino acid widely conserved through evolution. Functional analysis of D3291V channels revealed a normal response to cytosolic Ca2+, a markedly reduced luminal Ca2+ sensitivity and, more importantly, an absence of normal response to 8-bromo-cAMP and forskolin stimulation in both transfected HEK293 and HL-1 cells. Our data support that the D3291V-RyR2 is a loss-of-function RyR2 variant responsible for an atypical form of CPVT inducing a mild dysfunction in basal conditions but leading potentially to fatal events through its unresponsiveness to adrenergic stimulation.
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Affiliation(s)
- Malorie Blancard
- Inserm, UMRS 1166, Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, 75013 Paris, France; (Z.T.-H.); (N.N.); (P.G.)
- Correspondence:
| | - Zahia Touat-Hamici
- Inserm, UMRS 1166, Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, 75013 Paris, France; (Z.T.-H.); (N.N.); (P.G.)
| | - Yuriana Aguilar-Sanchez
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, IL 60612, USA; (Y.A.-S.); (J.R.-F.)
| | - Liheng Yin
- Inserm, UMRS 1180, Université Paris Saclay, 92290 Châtenay-Malabry, France; (L.Y.); (A.M.G.)
| | - Guy Vaksmann
- Service de Cardiologie Pédiatrique, Hôpital Privé de la Louvière, 59042 Lille, France;
| | | | | | - Isabelle Denjoy
- Département de Cardiologie, Centre de Référence des Maladies Cardiaques Héréditaires, Hôpital Bichat, AP-HP, 75018 Paris, France;
| | - Didier Klug
- Hôpital Cardiologique, CHRU de Lille, 59000 Lille, France;
| | - Nathalie Neyroud
- Inserm, UMRS 1166, Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, 75013 Paris, France; (Z.T.-H.); (N.N.); (P.G.)
| | - Josefina Ramos-Franco
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, IL 60612, USA; (Y.A.-S.); (J.R.-F.)
| | - Ana Maria Gomez
- Inserm, UMRS 1180, Université Paris Saclay, 92290 Châtenay-Malabry, France; (L.Y.); (A.M.G.)
| | - Pascale Guicheney
- Inserm, UMRS 1166, Institute of Cardiometabolism and Nutrition (ICAN), Sorbonne Université, 75013 Paris, France; (Z.T.-H.); (N.N.); (P.G.)
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19
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Roston TM, Grewal J, Krahn AD. Pregnancy in catecholaminergic polymorphic ventricular tachycardia: therapeutic optimization and multidisciplinary care are key to success. Herzschrittmacherther Elektrophysiol 2021; 32:199-206. [PMID: 33881608 DOI: 10.1007/s00399-021-00755-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 01/07/2021] [Accepted: 03/18/2021] [Indexed: 10/21/2022]
Abstract
Women of child-bearing age comprise a large proportion of the patients followed by inherited arrhythmia clinics. Despite being a rare and dangerous diagnosis, cardiac and obstetric care providers should know that catecholaminergic polymorphic ventricular tachycardia (CPVT) is not a contraindication to pregnancy. In fact, pregnancy was not associated with an increased risk of CPVT-associated arrhythmias in a recent large cohort study, and most guideline-based anti-arrhythmic drug treatments are life-saving and carry a low risk of teratogenesis. In principle, the potential for CPVT destabilization may be more likely to occur after anti-arrhythmic drugs are decreased or stopped during pregnancy, when an implantable cardioverter defibrillator (ICD) shock exacerbates catecholamine release, or if adrenaline surges are triggered by labor and delivery. Therefore, all pregnant women should be followed by a cardio-obstetrics team with extensive knowledge of CPVT diagnosis, as well as arrhythmia risk stratification fand management. This multidisciplinary care should begin preconception and involve counseling on preimplantation genetic testing, choosing safe and effective anti-arrhythmic drugs, stopping contraindicated medications, optimal programming of ICDs, and planning for the brief hyper-adrenergic period of labor and delivery. The latest data on pregnancy in CPVT is reviewed here and the optimal care for this rare and complex patient population outlined.
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Affiliation(s)
- Thomas M Roston
- Centre for Cardiovascular Innovation, Division of Cardiology, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Jasmine Grewal
- Centre for Cardiovascular Innovation, Division of Cardiology, Department of Medicine, The University of British Columbia, Vancouver, Canada
| | - Andrew D Krahn
- Centre for Cardiovascular Innovation, Division of Cardiology, Department of Medicine, The University of British Columbia, Vancouver, Canada. .,, 211-1033 Davie Street, V6E 1M7, Vancouver, BC, Canada.
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20
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Burg S, Attali B. Targeting of Potassium Channels in Cardiac Arrhythmias. Trends Pharmacol Sci 2021; 42:491-506. [PMID: 33858691 DOI: 10.1016/j.tips.2021.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 03/14/2021] [Accepted: 03/17/2021] [Indexed: 02/07/2023]
Abstract
Cardiomyocytes are endowed with a complex repertoire of ion channels, responsible for the generation of action potentials (APs), travelling waves of electrical excitation, propagating throughout the heart and leading to cardiac contractions. Cardiac AP waveforms are shaped by a striking diversity of K+ channels. The pivotal role of K+ channels in cardiac health and disease is underscored by the dramatic impact that K+ channel dysfunction has on cardiac arrhythmias. The development of drugs targeted to specific K+ channels is expected to provide an optimized approach to antiarrhythmic therapy. Here, we review the functional roles of cardiac potassium channels under normal and diseased states. We survey current antiarrhythmic drugs (AADs) targeted to voltage-gated and Ca2+-activated K+ channels and highlight future research opportunities.
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21
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Christina G, Peter J, Bernhard S, Gerhard P. Catecholaminergic polymorphic ventricular tachycardia complicated by dilated cardiomyopathy: a case report. Eur Heart J Case Rep 2021; 4:1-6. [PMID: 33447728 PMCID: PMC7793240 DOI: 10.1093/ehjcr/ytaa299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 05/02/2020] [Revised: 06/17/2020] [Accepted: 08/05/2020] [Indexed: 11/26/2022]
Abstract
Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a severe genetic arrhythmogenic disorder characterized by adrenergically induced ventricular tachycardia manifesting as stress-induced syncope and sudden cardiac death. While CPVT is not associated with dilated cardiomyopathy (DCM) in most cases, the combination of both disease entities poses a major diagnostic and therapeutic challenge. Case summary We present the case of a young woman with CPVT. The clinical course since childhood was characterized by repetitive episodes of exercise-induced ventricular arrhythmias and a brady-tachy syndrome due to rapid paroxysmal atrial fibrillation and sinus bradycardia. Medical treatment included propranolol and flecainide until echocardiography showed a dilated left ventricle with severely depressed ejection fraction when the patient was 32 years old. Cardiac magnetic resonance imaging revealed non-specific late gadolinium enhancement. Myocardial inflammation, however, was excluded by subsequent endomyocardial biopsy. Genetic analysis confirmed a mutation in the cardiac ryanodine receptor but no pathogenetic variant associated with DCM. Guideline-directed medical therapy for HFrEF was limited due to symptomatic hypotension. Over the next months, the patient developed progressive heart failure symptoms that were finally managed by heart transplantation. Discussion Management in patients with CPVT and DCM is challenging, as Class I antiarrhythmic drugs are not recommended in structural heart disease and prophylactic internal cardioverter-defibrillator implantation without adjuvant antiarrhythmic therapy can be detrimental. Regular echocardiographic screening for DCM is recommendable in patients with CPVT. A multidisciplinary team of heart failure specialists, electrophysiologists, geneticists, and imaging specialists is needed to collaborate in the delivery of clinical care.
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Affiliation(s)
- Granitz Christina
- Clinic of Internal Medicine II, Department of Cardiology, Paracelsus Medical University of Salzburg, Müllner Hauptstrasse 48, 5020 Salzburg, Austria
| | - Jirak Peter
- Clinic of Internal Medicine II, Department of Cardiology, Paracelsus Medical University of Salzburg, Müllner Hauptstrasse 48, 5020 Salzburg, Austria
| | - Strohmer Bernhard
- Clinic of Internal Medicine II, Department of Cardiology, Paracelsus Medical University of Salzburg, Müllner Hauptstrasse 48, 5020 Salzburg, Austria
| | - Pölzl Gerhard
- Clinic of Internal Medicine III, Department of Cardiology and Angiology, University Hospital Innsbruck, Anichstraße 35, 6020 Innsbruck, Austria
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Saljic A, Muthukumarasamy KM, la Cour JM, Boddum K, Grunnet M, Berchtold MW, Jespersen T. Impact of arrhythmogenic calmodulin variants on small conductance Ca 2+ -activated K + (SK3) channels. Physiol Rep 2020; 7:e14210. [PMID: 31587513 PMCID: PMC6778599 DOI: 10.14814/phy2.14210] [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: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 02/07/2023] Open
Abstract
Calmodulin (CaM) is a ubiquitous Ca2+‐sensing protein regulating many important cellular processes. Several CaM‐associated variants have been identified in a small group of patients with cardiac arrhythmias. The mechanism remains largely unknown, even though a number of ion channels, including the ryanodine receptors and the L‐type calcium channels have been shown to be functionally affected by the presence of mutant CaM. CaM is constitutively bound to the SK channel, which underlies the calcium‐gated ISK contributing to cardiac repolarization. The CaM binding to SK channels is essential for gating, correct assembly, and membrane expression. To elucidate the effect of nine different arrhythmogenic CaM variants on SK3 channel function, HEK293 cells stably expressing SK3 were transiently co‐transfected with CaMWT or variant and whole‐cell patch‐clamp recordings were performed with a calculated free Ca2+ concentration of 400 nmol/L. MDCK cells were transiently transfected with SK3 and/or CaMWT or variant to address SK3 and CaM localization by immunocytochemistry. The LQTS‐associated variants CaMD96V, CaMD130G, and CaMF142L reduced ISK,Ca compared with CaMWT (P < 0.01, P < 0.001, and P < 0.05, respectively). The CPVT associated variant CaMN54I also reduced the ISK,Ca (P < 0.05), which was linked to an accumulation of SK3/CaMN54I channel complexes in intracellular compartments (P < 0.05). The CPVT associated variants, CaMA103V and CaMD132E only revealed a tendency toward reduced current, while the variants CaMF90L and CaMN98S, causing LQTS syndrome, did not have any impact on ISK,Ca. In conclusion, we found that the arrhythmogenic CaM variants CaMN54I, CaMD96V, CaMD130G, and CaMF142L significantly down‐regulate the SK3 channel current, but with distinct mechanism.
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Affiliation(s)
- Arnela Saljic
- Laboratory of Cardiac Physiology, Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kalai Mangai Muthukumarasamy
- Laboratory of Cardiac Physiology, Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonas Marstrand la Cour
- Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kim Boddum
- Laboratory of Cardiac Physiology, Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Martin Werner Berchtold
- Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Laboratory of Cardiac Physiology, Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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Stępień-Wojno M, Ponińska J, Biernacka EK, Foss-Nieradko B, Chwyczko T, Syska P, Płoski R, Bilińska ZT. A Recurrent Exertional Syncope and Sudden Cardiac Arrest in a Young Athlete with Known Pathogenic p.Arg420Gln Variant in the RYR2 Gene. Diagnostics (Basel) 2020; 10:diagnostics10070435. [PMID: 32605058 PMCID: PMC7399804 DOI: 10.3390/diagnostics10070435] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [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: 05/26/2020] [Revised: 06/17/2020] [Accepted: 06/25/2020] [Indexed: 11/16/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is one of causes of sudden cardiac death in the young, especially in athletes. Diagnosis of CPVT may be difficult since all cardiological examinations performed at rest are usually normal, and exercise stress test-induced ventricular tachycardia is not commonly present. The identification of a pathogenic mutation in RYR2 or CASQ2 is diagnostic in CPVT. We report on a 20-year-old athlete who survived two sudden cardiac arrests during swimming. Moreover, he suffered repeated syncopal spells on exercise. The diagnosis was made only following genetic testing using a multi-gene panel, and the p.Arg420Gln RYR2 variant was identified. We present diagnostic and therapeutic issues in this young athlete with CPVT.
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Affiliation(s)
- Małgorzata Stępień-Wojno
- Unit for Screening Studies in Inherited Cardiovascular Diseases, National Institute of Cardiology, 04-628 Warsaw, Poland; (M.S.-W.); (B.F.-N.)
| | - Joanna Ponińska
- Department of Medical Biology, National Institute of Cardiology, 04-628 Warsaw, Poland;
| | - Elżbieta K. Biernacka
- Department of Congenital Heart Diseases, National Institute of Cardiology, 04-628 Warsaw, Poland;
| | - Bogna Foss-Nieradko
- Unit for Screening Studies in Inherited Cardiovascular Diseases, National Institute of Cardiology, 04-628 Warsaw, Poland; (M.S.-W.); (B.F.-N.)
| | - Tomasz Chwyczko
- Department of Coronary Artery Disease and Cardiac Rehabilitation, National Institute of Cardiology, 04-628 Warsaw, Poland;
| | - Piotr Syska
- 2nd Department of Arrhythmia, National Institute of Cardiology, 04-628 Warsaw, Poland;
| | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, 02-106 Warsaw, Poland;
| | - Zofia T. Bilińska
- Unit for Screening Studies in Inherited Cardiovascular Diseases, National Institute of Cardiology, 04-628 Warsaw, Poland; (M.S.-W.); (B.F.-N.)
- Correspondence:
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Holt C, Hamborg L, Lau K, Brohus M, Sørensen AB, Larsen KT, Sommer C, Van Petegem F, Overgaard MT, Wimmer R. The arrhythmogenic N53I variant subtly changes the structure and dynamics in the calmodulin N-terminal domain, altering its interaction with the cardiac ryanodine receptor. J Biol Chem 2020; 295:7620-7634. [PMID: 32317284 DOI: 10.1074/jbc.ra120.013430] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [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: 03/13/2020] [Revised: 04/18/2020] [Indexed: 12/11/2022] Open
Abstract
Mutations in the genes encoding the highly conserved Ca2+-sensing protein calmodulin (CaM) cause severe cardiac arrhythmias, including catecholaminergic polymorphic ventricular tachycardia or long QT syndrome and sudden cardiac death. Most of the identified arrhythmogenic mutations reside in the C-terminal domain of CaM and mostly affect Ca2+-coordinating residues. One exception is the catecholaminergic polymorphic ventricular tachycardia-causing N53I substitution, which resides in the N-terminal domain (N-domain). It does not affect Ca2+ coordination and has only a minor impact on binding affinity toward Ca2+ and on other biophysical properties. Nevertheless, the N53I substitution dramatically affects CaM's ability to reduce the open probability of the cardiac ryanodine receptor (RyR2) while having no effect on the regulation of the plasmalemmal voltage-gated Ca2+ channel, Cav1.2. To gain more insight into the molecular disease mechanism of this mutant, we used NMR to investigate the structures and dynamics of both apo- and Ca2+-bound CaM-N53I in solution. We also solved the crystal structures of WT and N53I CaM in complex with the primary calmodulin-binding domain (CaMBD2) from RyR2 at 1.84-2.13 Å resolutions. We found that all structures of the arrhythmogenic CaM-N53I variant are highly similar to those of WT CaM. However, we noted that the N53I substitution exposes an additional hydrophobic surface and that the intramolecular dynamics of the protein are significantly altered such that they destabilize the CaM N-domain. We conclude that the N53I-induced changes alter the interaction of the CaM N-domain with RyR2 and thereby likely cause the arrhythmogenic phenotype of this mutation.
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Affiliation(s)
- Christian Holt
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
| | - Louise Hamborg
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
| | - Kelvin Lau
- University of British Columbia, Department of Biochemistry and Molecular Biology, V6T 1Z3 Vancouver, British Columbia, Canada
| | - Malene Brohus
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
| | | | | | - Cordula Sommer
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
| | - Filip Van Petegem
- University of British Columbia, Department of Biochemistry and Molecular Biology, V6T 1Z3 Vancouver, British Columbia, Canada
| | | | - Reinhard Wimmer
- Aalborg University, Department of Chemistry and Bioscience, 9220 Aalborg, Denmark
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Veith M, El-Battrawy I, Roterberg G, Raschwitz L, Lang S, Wolpert C, Schimpf R, Zhou X, Akin I, Borggrefe M. Long-Term Follow-Up of Patients with Catecholaminergic Polymorphic Ventricular Arrhythmia. J Clin Med 2020; 9:jcm9040903. [PMID: 32218223 PMCID: PMC7230751 DOI: 10.3390/jcm9040903] [Citation(s) in RCA: 4] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 03/10/2020] [Indexed: 11/24/2022] Open
Abstract
Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited disorder causing life-threatening arrhythmias. Long-term outcome studies of the channelopathy are limited. Objective: The aim of the present study was to summarize our knowledge on CPVT patients, including the clinical profile treatment approach and long-term outcome. Methods: In this single center study, we retrospectively and prospectively collected data from nine CPVT patients and analyzed them. Results: We reviewed nine patients with CPVT in seven families (22% male), with a median follow-up time of 8.6 years. Mean age at diagnosis was 26.4 ± 12 years. Symptoms at admission were syncope (four patients) and aborted cardiac arrest (four patients). Family history of sudden cardiac death was screened in five patients. In genetic analyses, we found five patients with ryanodine type 2 receptor (RYR2) mutations. Seven patients were treated with beta-blockers, and if symptoms persisted flecainide was added (four patients). Despite beta-blocker treatment, three patients suffered from seven adverse cardiac events. An implantable cardioverter defibrillator was implanted in seven patients (one primary, six secondary prevention). Over the follow-up period, three patients suffered from ventricular tachycardia (ten times) and five patients from ventricular fibrillation (nine times). No one died during follow-up. Conclusion: Our CPVT cohort showed a high risk of cardiac events. Family screening, optimal medical therapy and individualized treatment are necessary in affected patients in referral centers.
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Affiliation(s)
- Michael Veith
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
- Correspondence: (M.V.); (I.E.-B.)
| | - Ibrahim El-Battrawy
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
- DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, 68167 Mannheim, Germany
- Correspondence: (M.V.); (I.E.-B.)
| | - Gretje Roterberg
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
| | - Laura Raschwitz
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
| | - Siegfried Lang
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
- DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, 68167 Mannheim, Germany
| | - Christian Wolpert
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
| | - Rainer Schimpf
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
| | - Xiaobo Zhou
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
- DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, 68167 Mannheim, Germany
| | - Ibrahim Akin
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
- DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, 68167 Mannheim, Germany
| | - Martin Borggrefe
- First Department of Medicine, Faculty of Medicine, University Medical Centre Mannheim (UMM), University of Heidelberg, 68167 Mannheim, Germany; (G.R.); (L.R.); (S.L.); (C.W.); (R.S.); (X.Z.); (I.A.); (M.B.)
- DZHK (German Center for Cardiovascular Research), Partner Site, Heidelberg-Mannheim, 68167 Mannheim, Germany
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Moscu-Gregor A, Marschall C, Müntjes C, Schönecker A, Schuessler-Hahn F, Hohendanner F, Parwani AS, Boldt LH, Ott CE, Bennewiz A, Paul T, Krause U, Rost I. Novel variants in TECRL cause recessive inherited CPVT type 3 with severe and variable clinical symptoms. J Cardiovasc Electrophysiol 2020; 31:1527-1535. [PMID: 32173957 DOI: 10.1111/jce.14446] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [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: 12/02/2019] [Revised: 01/27/2020] [Accepted: 02/17/2020] [Indexed: 12/20/2022]
Abstract
INTRODUCTION Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome characterized by adrenergically stimulated ventricular tachycardia. The most common form of CPVT is due to autosomal dominant variants in the cardiac ryanodine-receptor gene (RYR2). However, trans-2,3-enoyl-CoA reductase-like (TECRL) was recently suggested to be a novel candidate gene for life-threatening inherited arrhythmias. Patients previously reported with pathogenic changes in TECRL showed a special mixed phenotype of CPVT and long-QT-syndrome (LQTS) termed CPVT type 3 (CPVT3), an autosomal recessive disorder. METHODS AND RESULTS We implemented TECRL into our NGS panel diagnostics for CPVT and LQTS in April 2017. By December 2018, 631 index patients with suspected CPVT or LQTS had been referred to our laboratory for genetic testing. Molecular analysis identified four Caucasian families carrying novel variants in TECRL. One patient was homozygous for Gln139* resulting in a premature stop codon and loss-of-function of the TECRL protein. Another patient was homozygous for Pro290His, probably leading to an altered folding of the 3-oxo-5-alpha steroid 4-dehydrogenase domain of the TECRL protein. The LOF-variant Ser309* and the missense-variant Val298Ala have been shown to be compound heterozygous in another individual. NGS-based copy number variation analysis and quantitative PCR revealed a quadruplication of TECRL in the last individual, which is likely to be a homozygous duplication. CONCLUSION The data from our patient collective indicate that CPVT3 occurs much more frequently than previously expected. Variants in TECRL may be causative in up to 5% of all CPVT cases. According to these findings, the default analysis of this gene is recommended if CPVT is suspected.
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Affiliation(s)
| | - Christoph Marschall
- Department of Molecular Genetics, MVZ Martinsried GmbH, Martinsried, Germany
| | - Carsten Müntjes
- Department of Pediatric Cardiology, Clinic for Pediatrics III, Essen University Hospital, Essen, Germany
| | - Anne Schönecker
- Department of Pediatric Cardiology, Clinic for Pediatrics III, Essen University Hospital, Essen, Germany
| | | | - Felix Hohendanner
- Division of Cardiology, Medical Department, Charité Campus Virchow-Klinikum, Berlin, Germany
| | - Abdul Shokor Parwani
- Division of Cardiology, Medical Department, Charité Campus Virchow-Klinikum, Berlin, Germany
| | - Leif-Hendrik Boldt
- Division of Cardiology, Medical Department, Charité Campus Virchow-Klinikum, Berlin, Germany
| | - Claus-Eric Ott
- Institute of Medical Genetics and Human Genetics, Charité, Berlin, Germany
| | - Anja Bennewiz
- Praxis-Kinderherz, Gesundheitszentrum Am Borsigturm, Berlin, Germany
| | - Thomas Paul
- Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, University Medical Center/Göttingen, Göttingen, Germany
| | - Ulrich Krause
- Department of Pediatric Cardiology and Pediatric Intensive Care Medicine, University Medical Center/Göttingen, Göttingen, Germany
| | - Imma Rost
- Department of Molecular Genetics, MVZ Martinsried GmbH, Martinsried, Germany
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27
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Chazin WJ, Johnson CN. Calmodulin Mutations Associated with Heart Arrhythmia: A Status Report. Int J Mol Sci 2020; 21:E1418. [PMID: 32093079 DOI: 10.3390/ijms21041418] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [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: 02/03/2020] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 02/06/2023] Open
Abstract
Calmodulin (CaM) is a ubiquitous intracellular Ca2+ sensing protein that modifies gating of numerous ion channels. CaM has an extraordinarily high level of evolutionary conservation, which led to the fundamental assumption that mutation would be lethal. However, in 2012, complete exome sequencing of infants suffering from recurrent cardiac arrest revealed de novo mutations in the three human CALM genes. The correlation between mutations and pathophysiology suggests defects in CaM-dependent ion channel functions. Here, we review the current state of the field for all reported CaM mutations associated with cardiac arrhythmias, including knowledge of their biochemical and structural characteristics, and progress towards understanding how these mutations affect cardiac ion channel function.
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28
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Bennett JS, Bernhardt M, McBride KL, Reshmi SC, Zmuda E, Kertesz NJ, Garg V, Fitzgerald-Butt S, Kamp AN. Reclassification of Variants of Uncertain Significance in Children with Inherited Arrhythmia Syndromes is Predicted by Clinical Factors. Pediatr Cardiol 2019; 40:1679-1687. [PMID: 31535183 DOI: 10.1007/s00246-019-02203-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [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: 03/30/2019] [Accepted: 08/28/2019] [Indexed: 12/19/2022]
Abstract
Genetic testing is important to augment clinical diagnosis and inform management of inherited arrhythmias syndromes (IAS), but variants of uncertain significance (VUS) are common and remain a challenge in clinical practice. In 2015, American College of Medical Genetics (ACMG) published updated guidelines for interpretation of genetic results. Despite increasing understanding of human genomic variation, there are no guidelines for reinterpretation of prior genetic test results. Patients at a single tertiary children's hospital with genetic testing for an IAS that demonstrated a VUS were re-evaluated using 2015 ACMG guidelines, clinical information, and publically available databases. Search of the electronic medical record identified 116 patients with genetic testing results available, and 24/116 (21%) harbored a VUS for an IAS. 23 unique VUS were evaluated from 12 genes. Over half of the VUS (12/23 (52%)) were reclassified using 2015 criteria, and 8 (35%) changed to pathogenic and 4 (17%) to benign. Relative risk of reclassification of VUS to a pathogenic variant in a patient with confirmed clinical diagnosis was 4.1 (95% CI 1.23-15.4). Reclassification was not associated with initial testing year. These data demonstrate 52% of VUS in children with IAS are reclassified with application of 2015 ACMG guidelines. Strength of phenotyping is associated with eventual pathogenic classification of genetic variants and periodic re-evaluation of VUS identified on genetic testing for IAS is warranted.
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Affiliation(s)
- Jeffrey S Bennett
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,The Heart Center, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Madison Bernhardt
- Department of Medical Genetics, St. Luke's Mountain States Tumor Institute, Boise, ID, USA
| | - Kim L McBride
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Division of Genetic and Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, USA.,The Center for Cardiovascular Research, Nationwide Children's Hospital, Columbus, OH, USA
| | - Shalini C Reshmi
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Erik Zmuda
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Naomi J Kertesz
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,The Heart Center, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Vidu Garg
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,The Heart Center, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.,The Center for Cardiovascular Research, Nationwide Children's Hospital, Columbus, OH, USA
| | - Sara Fitzgerald-Butt
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anna N Kamp
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA. .,The Heart Center, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.
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29
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Pölönen RP, Swan H, Aalto-Setälä K. Mutation-specific differences in arrhythmias and drug responses in CPVT patients: simultaneous patch clamp and video imaging of iPSC derived cardiomyocytes. Mol Biol Rep 2019; 47:1067-1077. [PMID: 31786768 DOI: 10.1007/s11033-019-05201-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 11/21/2019] [Indexed: 12/26/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac disease characterized by arrhythmias under adrenergic stress. Mutations in the cardiac ryanodine receptor (RYR2) are the leading cause for CPVT. We characterized electrophysiological properties of CPVT patient-specific induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) carrying different mutations in RYR2 and evaluated effects of carvedilol and flecainide on action potential (AP) and contractile properties of hiPSC-CMs. iPSC-CMs were generated from skin biopsies of CPVT patients carrying exon 3 deletion (E3D) and L4115F mutation in RYR2. APs and contractile movement were recorded simultaneously from the same hiPSC-CMs. Differences in AP properties of ventricular like CMs were seen in CPVT and control CMs: APD90 of both E3D (n = 20) and L4115F (n = 25) CPVT CMs was shorter than in control CMs (n = 15). E3D-CPVT CMs had shortest AP duration, lowest AP amplitude, upstroke velocity and more depolarized diastolic potential than controls. Adrenaline had positive and carvedilol and flecainide negative chronotropic effect in all hiPSC CMs. CPVT CMs had increased amount of delayed after depolarizations (DADs) and early after depolarizations (EADs) after adrenaline exposure. E3D CPVT CMs had the most DADs, EADs, and tachyarrhythmia. Discordant negatively coupled alternans was seen in L4115F CPVT CMs. Carvedilol cured almost all arrhythmias in L4115F CPVT CMs. Both drugs decreased contraction amplitude in all hiPSC CMs. E3D CPVT CMs have electrophysiological properties, which render them more prone to arrhythmias. iPSC-CMs provide a unique platform for disease modeling and drug screening for CPVT. Combining electrophysiological measurements, we can gain deeper insight into mechanisms of arrhythmias.
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Affiliation(s)
- R P Pölönen
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, Arvo2 D441, 33520, Tampere, Finland.
| | - H Swan
- Helsinki University Hospital and Helsinki University, PO Box 340, 00029, Helsinki, Finland
| | - K Aalto-Setälä
- Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, Arvo2 D441, 33520, Tampere, Finland
- Heart Center, Tampere University Hospital, Arvo Ylpön katu 34, Arvo2 D437, 33520, Tampere, Finland
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30
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Baltogiannis GG, Lysitsas DN, di Giovanni G, Ciconte G, Sieira J, Conte G, Kolettis TM, Chierchia GB, de Asmundis C, Brugada P. CPVT: Arrhythmogenesis, Therapeutic Management, and Future Perspectives. A Brief Review of the Literature. Front Cardiovasc Med 2019; 6:92. [PMID: 31380394 PMCID: PMC6644488 DOI: 10.3389/fcvm.2019.00092] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 06/21/2019] [Indexed: 11/25/2022] Open
Abstract
Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a primary electrical disease characterized by a normal resting electrocardiogram and induction of malignant arrhythmias during adrenergic stress leading to syncope or sudden cardiac death (SCD). CPVT is caused by mutations in the cardiac ryanodine receptor (RyR2) or in the sarcoplasmic reticulum protein calsequestrin 2 genes (CASQ2). The RyR2 mutations are responsible for the autosomal dominant form of CPVT, while CASQ2 mutations are rare and account for the recessive form. These mutations cause a substantial inballance in the homeostasis of intracellular calcium resulting in polymorphic ventricular tachycardia through triggered activity. Beta blockers were for years the cornerstone of therapy in these patients. Sodium channel blockers, especially flecainide, have an additive role in those not responding in beta blockade. Implantation of defibrillators needs a meticulous evaluation since inappropriate shocks may lead to electrical storm. Finally, cardiac sympathetic denervation might also be an alternative therapeutic option. Early identification and risk stratification is of major importance in patients with CPVT. The aim of the present review is to present the arrhythmogenic mechanisms of the disease, the current therapies applied and potential future perspectives.
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Affiliation(s)
- Giannis G Baltogiannis
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium.,St. Luke's Hospital Thessaloniki, Thessaloniki, Greece
| | | | | | - Giuseppe Ciconte
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium
| | - Juan Sieira
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium
| | - Giulio Conte
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium
| | | | | | | | - Pedro Brugada
- Heart Rhythm Management Centre, Vrije University, Brussels, Belgium
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31
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Franciosi S, Roston TM, Perry FKG, Knollmann BC, Kannankeril PJ, Sanatani S. Chronotropic incompetence as a risk predictor in children and young adults with catecholaminergic polymorphic ventricular tachycardia. J Cardiovasc Electrophysiol 2019; 30:1923-1929. [PMID: 31231889 DOI: 10.1111/jce.14043] [Citation(s) in RCA: 9] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Risk stratification tools for catecholaminergic polymorphic ventricular tachycardia (CPVT) are limited. The exercise stress test (EST) is the most important diagnostic and prognostic test. We aimed to determine whether heart rate (HR) and blood pressure (BP) response during EST were associated with the risk of arrhythmias. MATERIALS AND METHODS We studied the association between HR and BP response and ventricular arrhythmia burden on EST in 20 CPVT patients. HR reserve values <80% and ≤62% were used to define chronotropic incompetence (CI) off and on therapy, respectively. Symptoms and ventricular arrhythmia score (VAS) in all patients with respect to CI and BP during index EST off therapy and on maximal therapy were compared. RESULTS CI in CPVT patients off therapy was associated with a worse VAS during EST (P = .046). Patients with CI also more frequently presented with syncope and/or cardiac arrest compared to patients with a normal chronotropic response (P = .008). Once on therapy, patients with CI had similar VAS compared to patients without CI (P = .50), suggesting that treatment attenuates risk related to CI. Patients with CI also had a lower peak systolic BP (P = .041) which persisted on maximal therapy (P = .033). CONCLUSION Untreated CPVT patients with CI have more ventricular arrhythmias than those without CI. This may serve as a simple disease prognosticator that can be modified by antiarrhythmic therapy. A mechanistic link between CI and arrhythmia susceptibility remains unknown. Larger studies are needed to confirm and establish the mechanism of these findings.
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Affiliation(s)
- Sonia Franciosi
- Division of Cardiology, Department of Pediatrics, Children's Heart Centre, BC Children's Hospital, University of British Columbia, Vancouver, Canada
| | - Thomas M Roston
- Division of Cardiology, Department of Pediatrics, Children's Heart Centre, BC Children's Hospital, University of British Columbia, Vancouver, Canada.,Department of Medicine, University of British Columbia, Vancouver, Canada.,Department of Medicine, University of Alberta, Edmonton, Canada
| | - Frances K G Perry
- Division of Cardiology, Department of Pediatrics, Children's Heart Centre, BC Children's Hospital, University of British Columbia, Vancouver, Canada
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Prince J Kannankeril
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee.,Department of Pediatrics, Vanderbilt University Medical Center, Monroe Carell Jr. Children's Hospital at Vanderbilt, Nashville, Tennessee
| | - Shubhayan Sanatani
- Division of Cardiology, Department of Pediatrics, Children's Heart Centre, BC Children's Hospital, University of British Columbia, Vancouver, Canada
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32
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Mahlke N, Dittmann S, Schulze-Bahr E, Ritz-Timme S, Hartung B. Sudden unexpected cardiac death and postmortem identification of a novel RYR2 gene mutation. Int J Legal Med 2019; 133:1835-8. [PMID: 31289932 DOI: 10.1007/s00414-019-02117-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 06/25/2019] [Indexed: 12/11/2022]
Abstract
A 13-year-old female was found lifeless at home. The autopsy and consecutive histological and toxicological examinations showed blood-rich and edematous lungs and foamy bloody content in the airways. No morphologic pathological findings were seen, especially no bleeding sources. Toxicological findings were unremarkable. The specific cause of death remained unclear. Due to reported losses of consciousness, a moleculargenetic postmortem testing was performed. A so far undescribed mutation in the cardiac ryanodine receptor gene RyR2 was detected. This mutation is suitable to explain the case history as well as the morphological findings. The cardiac ryanodine receptor gene RyR2 encodes the ryanodine receptor type 2, an ion channel in the cardiomyocytes. The ion channel regulates the influx of calcium ions and thus influences myocardial activity. Mutations in this channel may result in the catecholaminergic polymorphic ventricular tachycardia (CPVT), a cardiac arrhythmia that can lead to syncope and sudden cardiac death. This case demonstrates the usefulness and need of molecular autopsy, in particular to identify and treat possibly affected family members.
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33
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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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34
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Batiste SM, Blackwell DJ, Kim K, Kryshtal DO, Gomez-Hurtado N, Rebbeck RT, Cornea RL, Johnston JN, Knollmann BC. Unnatural verticilide enantiomer inhibits type 2 ryanodine receptor-mediated calcium leak and is antiarrhythmic. Proc Natl Acad Sci U S A 2019; 116:4810-5. [PMID: 30792355 DOI: 10.1073/pnas.1816685116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ca2+ leak via ryanodine receptor type 2 (RyR2) can cause potentially fatal arrhythmias in a variety of heart diseases and has also been implicated in neurodegenerative and seizure disorders, making RyR2 an attractive therapeutic target for drug development. Here we synthesized and investigated the fungal natural product and known insect RyR antagonist (-)-verticilide and several congeners to determine their activity against mammalian RyR2. Although the cyclooligomeric depsipeptide natural product (-)-verticilide had no effect, its nonnatural enantiomer [ent-(+)-verticilide] significantly reduced RyR2-mediated spontaneous Ca2+ leak both in cardiomyocytes from wild-type mouse and from a gene-targeted mouse model of Ca2+ leak-induced arrhythmias (Casq2-/-). ent-(+)-verticilide selectively inhibited RyR2-mediated Ca2+ leak and exhibited higher potency and a distinct mechanism of action compared with the pan-RyR inhibitors dantrolene and tetracaine and the antiarrhythmic drug flecainide. ent-(+)-verticilide prevented arrhythmogenic membrane depolarizations in cardiomyocytes without significant effects on the cardiac action potential and attenuated ventricular arrhythmia in catecholamine-challenged Casq2-/- mice. These findings indicate that ent-(+)-verticilide is a potent and selective inhibitor of RyR2-mediated diastolic Ca2+ leak, making it a molecular tool to investigate the therapeutic potential of targeting RyR2 hyperactivity in heart and brain pathologies. The enantiomer-specific activity and straightforward chemical synthesis of (unnatural) ent-(+)-verticilide provides a compelling argument to prioritize ent-natural product synthesis. Despite their general absence in nature, the enantiomers of natural products may harbor unprecedented activity, thereby leading to new scaffolds for probe and therapeutic development.
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35
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Abstract
Fluxes of calcium (Ca2+) across cell membranes enable fast cellular responses. Calmodulin (CaM) senses local changes in Ca2+ concentration and relays the information to numerous interaction partners. The critical role of accurate Ca2+ signaling on cellular function is underscored by the fact that there are three independent CaM genes (CALM1-3) in the human genome. All three genes are functional and encode the exact same CaM protein. Moreover, CaM has a completely conserved amino acid sequence across all vertebrates. Given this degree of conservation, it was long thought that mutations in CaM were incompatible with life. It was therefore a big surprise when the first CaM mutations in humans were identified six years ago. Today, more than a dozen human CaM missense mutations have been described, all found in patients with severe cardiac arrhythmias. Biochemical studies have demonstrated differential effects on Ca2+ binding affinities for these CaM variants. Moreover, CaM regulation of central cardiac ion channels is impaired, including the voltage-gated Ca2+ channel, CaV1.2, and the sarcoplasmic reticulum Ca2+ release channel, ryanodine receptor isoform 2, RyR2. Currently, no non-cardiac phenotypes have been described for CaM variant carriers. However, sequencing of large human cohorts reveals a cumulative frequency of additional rare CaM mutations that raise the possibility of CaM variants not exclusively causing severe cardiac arrhythmias. Here, we provide an overview of the identified CaM variants and their known consequences for target regulation and cardiac disease phenotype. We discuss experimental data, patient genotypes and phenotypes as well as which questions remain open to understand this complexity.
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Affiliation(s)
- Helene H Jensen
- Section for Biotechnology, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Malene Brohus
- Section for Biotechnology, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Mette Nyegaard
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Michael T Overgaard
- Section for Biotechnology, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
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36
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Acimovic I, Refaat MM, Moreau A, Salykin A, Reiken S, Sleiman Y, Souidi M, Přibyl J, Kajava AV, Richard S, Lu JT, Chevalier P, Skládal P, Dvořak P, Rotrekl V, Marks AR, Scheinman MM, Lacampagne A, Meli AC. Post-Translational Modifications and Diastolic Calcium Leak Associated to the Novel RyR2-D3638A Mutation Lead to CPVT in Patient-Specific hiPSC-Derived Cardiomyocytes. J Clin Med 2018; 7:jcm7110423. [PMID: 30413023 PMCID: PMC6262462 DOI: 10.3390/jcm7110423] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [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: 10/19/2018] [Revised: 10/31/2018] [Accepted: 11/04/2018] [Indexed: 12/14/2022] Open
Abstract
Background: Sarcoplasmic reticulum Ca2+ leak and post-translational modifications under stress have been implicated in catecholaminergic polymorphic ventricular tachycardia (CPVT), a highly lethal inherited arrhythmogenic disorder. Human induced pluripotent stem cells (hiPSCs) offer a unique opportunity for disease modeling. Objective: The aims were to obtain functional hiPSC-derived cardiomyocytes from a CPVT patient harboring a novel ryanodine receptor (RyR2) mutation and model the syndrome, drug responses and investigate the molecular mechanisms associated to the CPVT syndrome. Methods: Patient-specific cardiomyocytes were generated from a young athletic female diagnosed with CPVT. The contractile, intracellular Ca2+ handling and electrophysiological properties as well as the RyR2 macromolecular remodeling were studied. Results: Exercise stress electrocardiography revealed polymorphic ventricular tachycardia when treated with metoprolol and marked improvement with flecainide alone. We found abnormal stress-induced contractile and electrophysiological properties associated with sarcoplasmic reticulum Ca2+ leak in CPVT hiPSC-derived cardiomyocytes. We found inadequate response to metoprolol and a potent response of flecainide. Stabilizing RyR2 with a Rycal compound prevents those abnormalities specifically in CPVT hiPSC-derived cardiomyocytes. The RyR2-D3638A mutation is located in the conformational change inducing-central core domain and leads to RyR2 macromolecular remodeling including depletion of PP2A and Calstabin2. Conclusion: We identified a novel RyR2-D3638A mutation causing 3D conformational defects and aberrant biophysical properties associated to RyR2 macromolecular complex post-translational remodeling. The molecular remodeling is for the first time revealed using patient-specific hiPSC-derived cardiomyocytes which may explain the CPVT proband’s resistance. Our study promotes hiPSC-derived cardiomyocytes as a suitable model for disease modeling, testing new therapeutic compounds, personalized medicine and deciphering underlying molecular mechanisms.
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Affiliation(s)
- Ivana Acimovic
- Department of Biology, Faculty of Medicine, Masaryk University, Brno 62500, Czech Republic.
| | - Marwan M Refaat
- Department of Internal Medicine, Cardiology Division/Cardiac Electrophysiology Section and Department of Biochemistry and Molecular Genetics, American University of Beirut Faculty of Medicine and Medical Center, Beirut 1107 2020, Lebanon.
| | - Adrien Moreau
- NeuroMyoGène Institute, University of Claude Bernard Lyon 1, 69100 Villeurbanne, France.
- PhyMedExp, INSERM, University of Montpellier, CNRS, 371 Avenue du Doyen G. Giraud, 34295 Montpellier CEDEX 5, France.
| | - Anton Salykin
- Department of Biology, Faculty of Medicine, Masaryk University, Brno 62500, Czech Republic.
| | - Steve Reiken
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
| | - Yvonne Sleiman
- PhyMedExp, INSERM, University of Montpellier, CNRS, 371 Avenue du Doyen G. Giraud, 34295 Montpellier CEDEX 5, France.
| | - Monia Souidi
- PhyMedExp, INSERM, University of Montpellier, CNRS, 371 Avenue du Doyen G. Giraud, 34295 Montpellier CEDEX 5, France.
| | - Jan Přibyl
- CEITEC, Masaryk University, Brno 62500, Czech Republic.
| | - Andrey V Kajava
- CRBM, CNRS, University of Montpellier, 34293 Montpellier, France and University ITMO, St Petersburg 197101, Russia.
| | - Sylvain Richard
- PhyMedExp, INSERM, University of Montpellier, CNRS, 371 Avenue du Doyen G. Giraud, 34295 Montpellier CEDEX 5, France.
| | - Jonathan T Lu
- Department of Cardiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA.
| | - Philippe Chevalier
- NeuroMyoGène Institute, University of Claude Bernard Lyon 1, 69100 Villeurbanne, France.
| | - Petr Skládal
- CEITEC, Masaryk University, Brno 62500, Czech Republic.
| | - Petr Dvořak
- Department of Biology, Faculty of Medicine, Masaryk University, Brno 62500, Czech Republic.
| | - Vladimir Rotrekl
- Department of Biology, Faculty of Medicine, Masaryk University, Brno 62500, Czech Republic.
- International Clinical Research Center, St. Anne's University Hospital, Brno 60200, Czech Republic.
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
| | - Melvin M Scheinman
- San Francisco Medical Center, University of California, San Francisco, CA 94115, USA.
| | - Alain Lacampagne
- PhyMedExp, INSERM, University of Montpellier, CNRS, 371 Avenue du Doyen G. Giraud, 34295 Montpellier CEDEX 5, France.
| | - Albano C Meli
- PhyMedExp, INSERM, University of Montpellier, CNRS, 371 Avenue du Doyen G. Giraud, 34295 Montpellier CEDEX 5, France.
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37
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Seidlmayer LK, Riediger F, Pagonas N, Nordbeck P, Ritter O, Sasko B. Description of a novel RyR2 mutation in a juvenile patient with symptomatic catecholaminergic polymorphic ventricular tachycardia in sleep and during exercise: a case report. J Med Case Rep 2018; 12:298. [PMID: 30296944 PMCID: PMC6176516 DOI: 10.1186/s13256-018-1825-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 03/13/2018] [Accepted: 08/30/2018] [Indexed: 12/02/2022] Open
Abstract
Background Catecholaminergic polymorphic ventricular tachycardia is an inherited disease presenting with arrhythmic events during physical exercise or emotional stress. If untreated, catecholaminergic polymorphic ventricular tachycardia is a highly lethal condition: About 80% of affected individuals experience recurrent syncope, and 30% experience cardiac arrest. Catecholaminergic polymorphic ventricular tachycardia is caused by mutations in genes encoding ryanodine receptor type 2 (RyR2) and cardiac calsequestrin (CASQ2). In cases of sympathoadrenergic activation, both mutations result in a spontaneous Ca2+ release in cardiac cells, facilitating ventricular arrhythmias. Case presentation We present a case of a 17-year-old Caucasian boy who survived sudden cardiac death caused by ventricular fibrillation while performing running exercise in a fitness center. The diagnostic workup included blood tests, coronary angiography, electrophysiological testing, and cardiac magnetic resonance imaging, but all results were normal. Because the patient’s medical history included recurrent syncope during physical and emotional stress, we strongly suspected catecholaminergic polymorphic ventricular tachycardia as the underlying disease. Genetic screening was performed and confirmed the diagnosis, revealing a new heterozygous point mutation in the gene for RyR2, c.12520T>A (p.F4174 l, exon 90, RyR2 gene). The patient was discharged from our hospital after undergoing implantation of an implantable cardioverter defibrillator for secondary prevention. Shortly after implantation, the implantable cardioverter defibrillator terminated a sustaining ventricular tachycardia episode by antitachycardic pacing. This episode occurred early in the morning while the patient was asleep. Conclusions We present a case of catecholaminergic polymorphic ventricular tachycardia associated with a novel single point mutation in the RyR2 gene, which, to the best of our knowledge, has not been described in the literature so far. Our patient experienced arrhythmic events under both resting conditions and physical activity, an uncommon finding in patients with catecholaminergic polymorphic ventricular tachycardia. This novel mutation may cause arrhythmias independent of sympathoadrenergic stimulation, but further evidence is needed to prove causality.
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Affiliation(s)
- L K Seidlmayer
- Internal Medicine 1, Department of Cardiology, University Hospital of Wurzburg, Oberduerrbacherstrasse 6, 97080, Wurzburg, Germany.,Comprehensive Heart Failure Center, Am Schwarzenberg 15, 97078, Wurzburg, Germany
| | - F Riediger
- Department of Cardiology, Brandenburg Medical School Brandenburg - Theodor Fontane (MHB), University Hospital Brandenburg, Hochstrasse 29, 14470, Brandenburg an der Havel, Germany
| | - N Pagonas
- Department of Cardiology, Brandenburg Medical School Brandenburg - Theodor Fontane (MHB), University Hospital Brandenburg, Hochstrasse 29, 14470, Brandenburg an der Havel, Germany
| | - P Nordbeck
- Internal Medicine 1, Department of Cardiology, University Hospital of Wurzburg, Oberduerrbacherstrasse 6, 97080, Wurzburg, Germany.,Comprehensive Heart Failure Center, Am Schwarzenberg 15, 97078, Wurzburg, Germany
| | - O Ritter
- Department of Cardiology, Brandenburg Medical School Brandenburg - Theodor Fontane (MHB), University Hospital Brandenburg, Hochstrasse 29, 14470, Brandenburg an der Havel, Germany
| | - B Sasko
- Department of Cardiology, Brandenburg Medical School Brandenburg - Theodor Fontane (MHB), University Hospital Brandenburg, Hochstrasse 29, 14470, Brandenburg an der Havel, Germany.
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O’Callaghan BM, Hancox JC, Stuart AG, Armstrong C, Williams MM, Hills A, Pearce H, Dent CL, Gable M, Walsh MA. A unique triadin exon deletion causing a null phenotype. HeartRhythm Case Rep 2018; 4:514-518. [PMID: 30479949 PMCID: PMC6241331 DOI: 10.1016/j.hrcr.2018.07.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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: 11/18/2022] Open
Affiliation(s)
| | - Jules C. Hancox
- School of Physiology and Pharmacology, Cardiovascular Research Laboratories, University of Bristol, Bristol, United Kingdom
| | - Alan G. Stuart
- Bristol Royal Hospital for Children, Bristol, United Kingdom
| | | | - Maggie M. Williams
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Alison Hills
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Hazel Pearce
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Carolyn L. Dent
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Mary Gable
- Genomic Diagnostics Laboratory, University Hospital Bristol, Bristol, United Kingdom
| | - Mark A. Walsh
- Bristol Royal Hospital for Children, Bristol, United Kingdom
- Address reprint requests and correspondence: Dr Mark A. Walsh, Our Lady's Children's Hospital, Crumlin, Cooley Road, Drimnagh, Dublin, Ireland.
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Kushnir A, Wajsberg B, Marks AR. Ryanodine receptor dysfunction in human disorders. Biochim Biophys Acta Mol Cell Res 2018; 1865:1687-1697. [PMID: 30040966 DOI: 10.1016/j.bbamcr.2018.07.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 07/13/2018] [Accepted: 07/14/2018] [Indexed: 01/07/2023]
Abstract
Regulation of intracellular calcium (Ca2+) is critical in all cell types. The ryanodine receptor (RyR), an intracellular Ca2+ release channel located on the sarco/endoplasmic reticulum (SR/ER), releases Ca2+ from intracellular stores to activate critical functions including muscle contraction and neurotransmitter release. Dysfunctional RyR-mediated Ca2+ handling has been implicated in the pathogenesis of inherited and non-inherited conditions including heart failure, cardiac arrhythmias, skeletal myopathies, diabetes, and neurodegenerative diseases. Here we have reviewed the evidence linking human disorders to RyR dysfunction and describe novel approaches to RyR-targeted therapeutics.
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Affiliation(s)
- Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA; Department of Medicine, Division of Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Benjamin Wajsberg
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA.
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Wei H, Zhang XH, Clift C, Yamaguchi N, Morad M. CRISPR/Cas9 Gene editing of RyR2 in human stem cell-derived cardiomyocytes provides a novel approach in investigating dysfunctional Ca 2+ signaling. Cell Calcium. 2018;73:104-111. [PMID: 29730419 DOI: 10.1016/j.ceca.2018.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/20/2018] [Accepted: 04/21/2018] [Indexed: 12/27/2022]
Abstract
Type-2 ryanodine receptors (RyR2s) play a pivotal role in cardiac excitation-contraction coupling by releasing Ca2+ from sarcoplasmic reticulum (SR) via a Ca2+ -induced Ca2+ release (CICR) mechanism. Two strategies have been used to study the structure-function characteristics of RyR2 and its disease associated mutations: (1) heterologous cell expression of the recombinant mutant RyR2s, and (2) knock-in mouse models harboring RyR2 point mutations. Here, we establish an alternative approach where Ca2+ signaling aberrancy caused by the RyR2 mutation is studied in human cardiomyocytes with robust CICR mechanism. Specifically, we introduce point mutations in wild-type RYR2 of human induced pluripotent stem cells (hiPSCs) by CRISPR/Cas9 gene editing, and then differentiate them into cardiomyocytes. To verify the reliability of this approach, we introduced the same disease-associated RyR2 mutation, F2483I, which was studied by us in hiPSC-derived cardiomyocytes (hiPSC-CMs) from a patient biopsy. The gene-edited F2483I hiPSC-CMs exhibited longer and wandering Ca2+ sparks, elevated diastolic Ca2+ leaks, and smaller SR Ca2+ stores, like those of patient-derived cells. Our CRISPR/Cas9 gene editing approach validated the feasibility of creating myocytes expressing the various RyR2 mutants, making comparative mechanistic analysis and pharmacotherapeutic approaches for RyR2 pathologies possible.
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Klipp RC, Li N, Wang Q, Word TA, Sibrian-Vazquez M, Strongin RM, Wehrens XHT, Abramson JJ. EL20, a potent antiarrhythmic compound, selectively inhibits calmodulin-deficient ryanodine receptor type 2. Heart Rhythm 2017; 15:578-586. [PMID: 29248564 DOI: 10.1016/j.hrthm.2017.12.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Indexed: 01/06/2023]
Abstract
BACKGROUND Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an arrhythmogenic disorder caused by mutations in the cardiac ryanodine receptor RyR2 that increase diastolic calcium cation (Ca2+) leak from the sarcoplasmic reticulum (SR). Calmodulin (CaM) dissociation from RyR2 has been associated with diastolic Ca2+ leak in heart failure. OBJECTIVE Determine whether the tetracaine-derivative compound EL20 inhibits abnormal Ca2+ release from RyR2 in a CPVT model and investigate the underlying mechanism of inhibition. METHODS Spontaneous Ca2+ sparks in cardiomyocytes and inducible ventricular tachycardia were assessed in a CPVT mouse model, which is heterozygous for the R176Q mutation in RyR2 (R176Q/+ mice) in the presence of EL20 or vehicle. Single-channel studies using sheep cardiac SR or purified RyR2 reconstituted into proteoliposomes with and without exogenous CaM were used to assess mechanisms of inhibition. RESULTS EL20 potently inhibits abnormal Ca2+ release in R176Q/+ myocytes (half-maximal inhibitory concentration = 35.4 nM) and diminishes arrhythmia in R176Q/+ mice. EL20 inhibition of single-channel activity of purified RyR2 occurs in a similar range as seen in R176Q/+ myocytes (half-maximal inhibitory concentration = 8.2 nM). Inhibition of single-channel activity for cardiac SR or purified RyR2 supplemented with 100-nM or 1-μM CaM shows a 200- to 1000-fold reduction in potency. CONCLUSION This work provides a potential therapeutic mechanism for the development of antiarrhythmic compounds that inhibit leaky RyR2 resulting from CaM dissociation, which is often associated with failing hearts. Our data also suggest that CaM dissociation may contribute to the pathogenesis of arrhythmias with the CPVT-linked R176Q mutation.
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Affiliation(s)
- Robert C Klipp
- Department of Physics, Portland State University, Portland, Oregon
| | - Na Li
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas; Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Qiongling Wang
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
| | - Tarah A Word
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
| | | | - Robert M Strongin
- Department of Chemistry, Portland State University, Portland, Oregon
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas; Section of Cardiovascular Research, Department of Medicine, Baylor College of Medicine, Houston, Texas; Section of Cardiology, Department of Medicine, Baylor College of Medicine, Houston, Texas; Department of Pediatrics, Baylor College of Medicine, Houston, Texas; Center for Space Medicine, Baylor College of Medicine, Houston, Texas
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Schweitzer MK, Wilting F, Sedej S, Dreizehnter L, Dupper NJ, Tian Q, Moretti A, My I, Kwon O, Priori SG, Laugwitz KL, Storch U, Lipp P, Breit A, Mederos y Schnitzler M, Gudermann T, Schredelseker J. Suppression of Arrhythmia by Enhancing Mitochondrial Ca 2+ Uptake in Catecholaminergic Ventricular Tachycardia Models. JACC Basic Transl Sci 2017; 2:737-747. [PMID: 29354781 PMCID: PMC5774336 DOI: 10.1016/j.jacbts.2017.06.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 11/30/2022]
Abstract
Cardiovascular disease-related deaths frequently arise from arrhythmias, but treatment options are limited due to perilous side effects of commonly used antiarrhythmic drugs. Cardiac rhythmicity strongly depends on cardiomyocyte Ca2+ handling and prevalent cardiac diseases are causally associated with perturbations in intracellular Ca2+ handling. Therefore, intracellular Ca2+ transporters are lead candidate structures for novel and safer antiarrhythmic therapies. Mitochondria and mitochondrial Ca2+ transport proteins are important regulators of cardiac Ca2+ handling. Here we evaluated the potential of pharmacological activation of mitochondrial Ca2+ uptake for the treatment of cardiac arrhythmia. To this aim,we tested substances that enhance mitochondrial Ca2+ uptake for their ability to suppress arrhythmia in a murine model for ryanodine receptor 2 (RyR2)-mediated catecholaminergic polymorphic ventricular tachycardia (CPVT) in vitro and in vivo and in induced pluripotent stem cell-derived cardiomyocytes from a CPVT patient. In freshly isolated cardiomyocytes of RyR2R4496C/WT mice efsevin, a synthetic agonist of the voltage-dependent anion channel 2 (VDAC2) in the outer mitochondrial membrane, prevented the formation of diastolic Ca2+ waves and spontaneous action potentials. The antiarrhythmic effect of efsevin was abolished by blockade of the mitochondrial Ca2+ uniporter (MCU), but could be reproduced using the natural MCU activator kaempferol. Both mitochondrial Ca2+ uptake enhancers (MiCUps), efsevin and kaempferol, significantly reduced episodes of stress-induced ventricular tachycardia in RyR2R4496C/WT mice in vivo and abolished diastolic, arrhythmogenic Ca2+ events in human iPSC-derived cardiomyocytes.
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Affiliation(s)
- Maria K. Schweitzer
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Fabiola Wilting
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Lisa Dreizehnter
- Department of Medicine (Cardiology), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Nathan J. Dupper
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California
| | - Qinghai Tian
- Institute for Molecular Cell Biology, University Medical Center, Saarland University, Homburg/Saar, Germany
| | - Alessandra Moretti
- Department of Medicine (Cardiology), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Ilaria My
- Department of Medicine (Cardiology), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Ohyun Kwon
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California
| | - Silvia G. Priori
- Molecular Cardiology, Istituto di ricovero e cura a carattere scientifico (IRCCS) Salvatore Maugeri Foundation, Pavia, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Karl-Ludwig Laugwitz
- Department of Medicine (Cardiology), Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Ursula Storch
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Peter Lipp
- Institute for Molecular Cell Biology, University Medical Center, Saarland University, Homburg/Saar, Germany
| | - Andreas Breit
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Michael Mederos y Schnitzler
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Thomas Gudermann
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
- Deutsches Zentrum für Herz-Kreislauf-Forschung, Partner Site Munich Heart Alliance, Munich, Germany
| | - Johann Schredelseker
- Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
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Walweel K, Oo YW, Laver DR. The emerging role of calmodulin regulation of RyR2 in controlling heart rhythm, the progression of heart failure and the antiarrhythmic action of dantrolene. Clin Exp Pharmacol Physiol 2017; 44:135-142. [PMID: 27626620 DOI: 10.1111/1440-1681.12669] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [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: 06/23/2016] [Revised: 08/27/2016] [Accepted: 09/09/2016] [Indexed: 11/28/2022]
Abstract
Cardiac output and rhythm depend on the release and the take-up of calcium from the sarcoplasmic reticulum (SR). Excessive diastolic calcium leak from the SR due to dysfunctional calcium release channels (RyR2) contributes to the formation of delayed after-depolarizations, which underlie the fatal arrhythmias that occur in heart failure and inherited syndromes. Calmodulin (CaM) is a calcium-binding protein that regulates target proteins and acts as a calcium sensor. CaM is comprised of two calcium-binding EF-hand domains and a flexible linker. CaM is an accessory protein that partially inhibits RyR2 channel activity. CaM is critical for normal cardiac function, and altered CaM binding and efficacy may contribute to defects in SR calcium release. The present paper reviews CaM binding to RyR2 and how it regulates RyR2 channel activity. It then goes on to review how mutations in the CaM amino acid sequence give rise to inherited syndromes such as Catecholaminergic Polymorphic Ventricular Tachychardia (CPVT) and long QT syndrome (LQTS). In addition, the role of reduced CaM binding to RyR2 that results from RyR2 phosphorylation or from oxidation of either RyR2 or CaM contributes to the progression of heart failure is reviewed. Finally, this manuscript reviews recent evidence that CaM binding to RyR2 is required for the inhibitory action of a pharmaceutical agent (dantrolene) on RyR2. Dantrolene is a clinically used muscle relaxant that has recently been found to exert antiarrhythmic effects against SR Ca2+ overload arrhythmias.
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Affiliation(s)
- Kafa Walweel
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
| | - Ye Win Oo
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
| | - Derek R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
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Gonano LA, Jones PP. FK506-binding proteins 12 and 12.6 (FKBPs) as regulators of cardiac Ryanodine Receptors: Insights from new functional and structural knowledge. Channels (Austin) 2017. [PMID: 28636428 DOI: 10.1080/19336950.2017.1344799] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Ryanodine Receptors (RyRs) are intracellular Ca2+ channels that mediate Ca2+ flux from the sarco(endo)plasmic reticulum in many cell types. The interaction of RyRs with FK506-binding proteins (FKBPs) has been proposed as an important regulatory mechanism, where the loss of this interaction leads to channel dysfunction. In the heart, phosphorylation of RyR has been suggested to disrupt the RyR-FKBP interaction promoting altered Ca2+ signaling, heart failure and arrhythmias. However, the functional result of FKBP interaction with RyR and how this interaction is regulated remains highly controversial. Recently, high resolution structures of RyR have provided novel aspects to the ongoing debate. This review will discuss the most recent functional data in light of these new structures.
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Affiliation(s)
- Luis A Gonano
- a Department of Physiology , School of Biomedical Sciences and HeartOtago, University of Otago , Dunedin, Otago , New Zealand
| | - Peter P Jones
- a Department of Physiology , School of Biomedical Sciences and HeartOtago, University of Otago , Dunedin, Otago , New Zealand
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Abstract
The cardiac channelopathies are a group of diseases with (disease-) specific electrocardiographic (ECG) characteristics and a disease-specific risk of sudden cardiac death (SCD). This group includes the Long QT Syndromes (LQTS), Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT), Brugada Syndrome (BrS), Short QT Syndromes (SQTS), and Early Repolarization Syndrome (ERS). In the past 2 decades the genetic basis for these disease entities has largely been unraveled and that, together with the identification of the genetic basis of the cardiomyopathies, has paved the way for the complete new field of Cardiogenetics. By virtue of the identification of the genetic underpinning of a given disease, presymptomatic carriers of the genetic aberrancy can be identified and timely treatment can be installed. In addition, it has become clear that the pathophysiological substrate of some diseases previously considered to be one disease is not identical, and this has led to gene-specific treatment in some and complete new treatment, based on the newly developed insight, in others. Finally, the genetic information proved to be important in the prediction of risk on lethal ventricular arrhythmias of affected individuals and that is the topic of this brief review.
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Affiliation(s)
- Arthur A M Wilde
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands; Princess Al-Jawhara Albrahim Centre of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Ahmad Amin
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands.
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Broendberg AK, Nielsen JC, Bjerre J, Pedersen LN, Kristensen J, Henriksen FL, Bundgaard H, Jensen HK. Nationwide experience of catecholaminergic polymorphic ventricular tachycardia caused by RyR2 mutations. Heart 2017; 103:901-909. [PMID: 28237968 DOI: 10.1136/heartjnl-2016-310509] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [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: 08/24/2016] [Revised: 12/30/2016] [Accepted: 01/23/2017] [Indexed: 01/27/2023] Open
Abstract
OBJECTIVE The aim of this study was to characterise disease penetrance, course of disease and use of antiarrhythmic medication and implantable cardioverter-defibrillator (ICD) therapy in a Danish nationwide cohort of patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) due to mutations in the ryanodine receptor-2 (RyR2) gene. METHODS The study population was identified through the national hereditary heart disease database (Progeny). The study population was divided into three groups: probands, symptomatic and asymptomatic relatives. RESULTS We identified 23 symptomatic probands, 18 symptomatic and 10 asymptomatic relatives with a RyR2 mutation. Twenty (87%) probands and 10 (36%) relatives had severe presenting symptoms (sudden cardiac death (SCD), aborted SCD (ASCD) or syncope).As compared with symptomatic relatives, probands had lower age at onset of symptoms (16 years (IQR, 10-33) vs 43 years (IQR, 25-54), p<0.0001) and were more prone to fatal or near-fatal events (ASCD, SCD) (16vs5, p<0.0001). Twenty-eight patients had an ICD implanted, and eight experienced appropriate ICD therapy during follow-up (65 months (IQR, 43-175)). Electrical storm was seen in two of the 28 ICD treated patients (7%). No patients receiving treatment died during follow-up (57 months (IQR, 32-139)). Multifocal atrial tachycardia was the predominant symptom in five patients. CONCLUSIONS In a national cohort of RyR2 mutation-positive CPVT patients, SCD, ASCD and syncope were presenting events in the majority of probands and also occurred in 36% of relatives identified through family screening. Probands were younger at disease onset and more prone to fatal or near-fatal events than relatives.
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Affiliation(s)
| | | | - Jesper Bjerre
- Department of Pediatrics, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | | | - Jens Kristensen
- Department of Cardiology, Aarhus University Hospital, DK-8200 Aarhus N, Denmark
| | - Finn Lund Henriksen
- Department of Cardiology, Odense University Hospital, DK-5000 Odense, Denmark
| | - Henning Bundgaard
- Department of Cardiology, The Heart Centre, Unit for Inherited Cardiac Diseases, Rigshospitalet, DK-2100 Copenhagen, Denmark
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Lavorato M, Iyer VR, Dewight W, Cupo RR, Debattisti V, Gomez L, De la Fuente S, Zhao YT, Valdivia HH, Hajnóczky G, Franzini-Armstrong C. Increased mitochondrial nanotunneling activity, induced by calcium imbalance, affects intermitochondrial matrix exchanges. Proc Natl Acad Sci U S A 2017; 114:E849-58. [PMID: 28096415 DOI: 10.1073/pnas.1617788113] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Exchanges of matrix contents are essential to the maintenance of mitochondria. Cardiac mitochondrial exchange matrix content in two ways: by direct contact with neighboring mitochondria and over longer distances. The latter mode is supported by thin tubular protrusions, called nanotunnels, that contact other mitochondria at relatively long distances. Here, we report that cardiac myocytes of heterozygous mice carrying a catecholaminergic polymorphic ventricular tachycardia-linked RyR2 mutation (A4860G) show a unique and unusual mitochondrial response: a significantly increased frequency of nanotunnel extensions. The mutation induces Ca2+ imbalance by depressing RyR2 channel activity during excitation-contraction coupling, resulting in random bursts of Ca2+ release probably due to Ca2+ overload in the sarcoplasmic reticulum. We took advantage of the increased nanotunnel frequency in RyR2A4860G+/- cardiomyocytes to investigate and accurately define the ultrastructure of these mitochondrial extensions and to reconstruct the overall 3D distribution of nanotunnels using electron tomography. Additionally, to define the effects of communication via nanotunnels, we evaluated the intermitochondrial exchanges of matrix-targeted soluble fluorescent proteins, mtDsRed and photoactivable mtPA-GFP, in isolated cardiomyocytes by confocal microscopy. A direct comparison between exchanges occurring at short and long distances directly demonstrates that communication via nanotunnels is slower.
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Devalla HD, Gélinas R, Aburawi EH, Beqqali A, Goyette P, Freund C, Chaix MA, Tadros R, Jiang H, Le Béchec A, Monshouwer-Kloots JJ, Zwetsloot T, Kosmidis G, Latour F, Alikashani A, Hoekstra M, Schlaepfer J, Mummery CL, Stevenson B, Kutalik Z, de Vries AA, Rivard L, Wilde AA, Talajic M, Verkerk AO, Al-Gazali L, Rioux JD, Bhuiyan ZA, Passier R. TECRL, a new life-threatening inherited arrhythmia gene associated with overlapping clinical features of both LQTS and CPVT. EMBO Mol Med 2016; 8:1390-1408. [PMID: 27861123 PMCID: PMC5167130 DOI: 10.15252/emmm.201505719] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [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] [Indexed: 01/06/2023] Open
Abstract
Genetic causes of many familial arrhythmia syndromes remain elusive. In this study, whole‐exome sequencing (WES) was carried out on patients from three different families that presented with life‐threatening arrhythmias and high risk of sudden cardiac death (SCD). Two French Canadian probands carried identical homozygous rare variant in TECRL gene (p.Arg196Gln), which encodes the trans‐2,3‐enoyl‐CoA reductase‐like protein. Both patients had cardiac arrest, stress‐induced atrial and ventricular tachycardia, and QT prolongation on adrenergic stimulation. A third patient from a consanguineous Sudanese family diagnosed with catecholaminergic polymorphic ventricular tachycardia (CPVT) had a homozygous splice site mutation (c.331+1G>A) in TECRL. Analysis of intracellular calcium ([Ca2+]i) dynamics in human induced pluripotent stem cell‐derived cardiomyocytes (hiPSC‐CMs) generated from this individual (TECRLHom‐hiPSCs), his heterozygous but clinically asymptomatic father (TECRLHet‐hiPSCs), and a healthy individual (CTRL‐hiPSCs) from the same Sudanese family, revealed smaller [Ca2+]i transient amplitudes as well as elevated diastolic [Ca2+]i in TECRLHom‐hiPSC‐CMs compared with CTRL‐hiPSC‐CMs. The [Ca2+]i transient also rose markedly slower and contained lower sarcoplasmic reticulum (SR) calcium stores, evidenced by the decreased magnitude of caffeine‐induced [Ca2+]i transients. In addition, the decay phase of the [Ca2+]i transient was slower in TECRLHom‐hiPSC‐CMs due to decreased SERCA and NCX activities. Furthermore, TECRLHom‐hiPSC‐CMs showed prolonged action potentials (APs) compared with CTRL‐hiPSC‐CMs. TECRL knockdown in control human embryonic stem cell‐derived CMs (hESC‐CMs) also resulted in significantly longer APs. Moreover, stimulation by noradrenaline (NA) significantly increased the propensity for triggered activity based on delayed afterdepolarizations (DADs) in TECRLHom‐hiPSC‐CMs and treatment with flecainide, a class Ic antiarrhythmic drug, significantly reduced the triggered activity in these cells. In summary, we report that mutations in TECRL are associated with inherited arrhythmias characterized by clinical features of both LQTS and CPVT. Patient‐specific hiPSC‐CMs recapitulated salient features of the clinical phenotype and provide a platform for drug screening evidenced by initial identification of flecainide as a potential therapeutic. These findings have implications for diagnosis and treatment of inherited cardiac arrhythmias.
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Affiliation(s)
- Harsha D Devalla
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Roselle Gélinas
- Montreal Heart Institute, Montreal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Elhadi H Aburawi
- Department of Pediatrics, College of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates
| | - Abdelaziz Beqqali
- Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Christian Freund
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands.,Leiden University Medical Center hiPSC Core Facility, Leiden, The Netherlands
| | - Marie-A Chaix
- Montreal Heart Institute, Montreal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Rafik Tadros
- Montreal Heart Institute, Montreal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada.,Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Hui Jiang
- Beijing Genomics Institute, Shenzhen, China.,Shenzhen Key Laboratory of Genomics, Shenzhen, China.,The Guangdong Enterprise Key Laboratory of Human Disease Genomics, Shenzhen, China
| | - Antony Le Béchec
- Vital-IT group, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | - Tom Zwetsloot
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Georgios Kosmidis
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | | | | | - Maaike Hoekstra
- Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jurg Schlaepfer
- Service de Cardiologie, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Christine L Mummery
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Brian Stevenson
- Vital-IT group, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Zoltan Kutalik
- Vital-IT group, Swiss Institute of Bioinformatics, Lausanne, Switzerland.,Institute of Social and Preventive Medicine, University Hospital (CHUV) and University of Lausanne, Lausanne, Switzerland
| | - Antoine Af de Vries
- Laboratory of Experimental Cardiology, Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.,ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
| | - Léna Rivard
- Montreal Heart Institute, Montreal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Arthur Am Wilde
- Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia
| | - Mario Talajic
- Montreal Heart Institute, Montreal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Arie O Verkerk
- Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Lihadh Al-Gazali
- Department of Pediatrics, College of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates
| | - John D Rioux
- Montreal Heart Institute, Montreal, QC, Canada .,Department of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Zahurul A Bhuiyan
- Laboratoire Génétiqué Moléculaire, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland
| | - Robert Passier
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands .,Department of Applied Stem Cell Technologies, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
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49
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Paludan-Müller C, Ahlberg G, Ghouse J, Herfelt C, Svendsen JH, Haunsø S, Kanters JK, Olesen MS. Integration of 60,000 exomes and ACMG guidelines question the role of Catecholaminergic Polymorphic Ventricular Tachycardia-associated variants. Clin Genet 2016; 91:63-72. [PMID: 27538377 DOI: 10.1111/cge.12847] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [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: 06/09/2016] [Revised: 08/12/2016] [Accepted: 08/15/2016] [Indexed: 01/13/2023]
Abstract
Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a highly lethal cardiac arrhythmia disease occurring during exercise or psychological stress. CPVT has an estimated prevalence of 1:10,000 and has mainly been associated with variants in calcium-regulating genes. Identification of potential false-positive pathogenic variants was conducted by searching the Exome Aggregation Consortium (ExAC) database (n = 60,706) for variants reported to be associated with CPVT. The pathogenicity of the interrogated variants was assessed using guidelines from the American College of Medical Genetics and Genomics (ACMG) and in silico prediction tools. Of 246 variants 38 (15%) variants previously associated with CPVT were identified in the ExAC database. We predicted the CPVT prevalence to be 1:132. The ACMG standards classified 29% of ExAC variants as pathogenic or likely pathogenic. The in silico predictions showed a reduced probability of disease-causing effect for the variants identified in the exome database (p < 0.001). We have observed a large overrepresentation of previously CPVT-associated variants in a large exome database. Based on the frequency of CPVT in the general population, it is less likely that the previously proposed variants are associated with a highly penetrant monogenic form of the disease.
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Affiliation(s)
- C Paludan-Müller
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Denmark.,Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - G Ahlberg
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Denmark.,Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - J Ghouse
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Denmark.,Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - C Herfelt
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Denmark.,Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - J H Svendsen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Denmark.,Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health Sciences, Copenhagen, Denmark
| | - S Haunsø
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Denmark.,Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, Faculty of Health Sciences, Copenhagen, Denmark
| | - J K Kanters
- Laboratory of Experimental Cardiology, Department of Biomedicine, University of Copenhagen, Copenhagen, Denmark.,Department of Cardiology, Herlev and Gentofte University Hospitals, Copenhagen, Denmark
| | - M S Olesen
- Danish National Research Foundation Centre for Cardiac Arrhythmia, Department of Biomedical Sciences, University of Copenhagen, Denmark.,Laboratory for Molecular Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
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50
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Preininger MK, Jha R, Maxwell JT, Wu Q, Singh M, Wang B, Dalal A, Mceachin ZT, Rossoll W, Hales CM, Fischbach PS, Wagner MB, Xu C. A human pluripotent stem cell model of catecholaminergic polymorphic ventricular tachycardia recapitulates patient-specific drug responses. Dis Model Mech 2016; 9:927-39. [PMID: 27491078 PMCID: PMC5047684 DOI: 10.1242/dmm.026823] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 07/13/2016] [Indexed: 01/07/2023] Open
Abstract
Although β-blockers can be used to eliminate stress-induced ventricular arrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), this treatment is unsuccessful in ∼25% of cases. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) generated from these patients have potential for use in investigating the phenomenon, but it remains unknown whether they can recapitulate patient-specific drug responses to β-blockers. This study assessed whether the inadequacy of β-blocker therapy in an individual can be observed in vitro using patient-derived CPVT iPSC-CMs. An individual with CPVT harboring a novel mutation in the type 2 cardiac ryanodine receptor (RyR2) was identified whose persistent ventricular arrhythmias during β-blockade with nadolol were abolished during flecainide treatment. iPSC-CMs generated from this patient and two control individuals expressed comparable levels of excitation-contraction genes, but assessment of the sarcoplasmic reticulum Ca(2+) leak and load relationship revealed intracellular Ca(2+) homeostasis was altered in the CPVT iPSC-CMs. β-adrenergic stimulation potentiated spontaneous Ca(2+) waves and unduly frequent, large and prolonged Ca(2+) sparks in CPVT compared with control iPSC-CMs, validating the disease phenotype. Pursuant to the patient's in vivo responses, nadolol treatment during β-adrenergic stimulation achieved negligible reduction of Ca(2+) wave frequency and failed to rescue Ca(2+) spark defects in CPVT iPSC-CMs. In contrast, flecainide reduced both frequency and amplitude of Ca(2+) waves and restored the frequency, width and duration of Ca(2+) sparks to baseline levels. By recapitulating the improved response of an individual with CPVT to flecainide compared with β-blocker therapy in vitro, these data provide new evidence that iPSC-CMs can capture basic components of patient-specific drug responses.
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MESH Headings
- Adrenergic beta-Antagonists/pharmacology
- Adrenergic beta-Antagonists/therapeutic use
- Arrhythmias, Cardiac/drug therapy
- Arrhythmias, Cardiac/physiopathology
- Biomarkers/metabolism
- Calcium/metabolism
- Calcium Signaling/drug effects
- Catecholamines/metabolism
- Cell Differentiation/drug effects
- Cell Lineage/drug effects
- Electrophysiological Phenomena/drug effects
- Female
- Flecainide/pharmacology
- Flecainide/therapeutic use
- Homeostasis/drug effects
- Humans
- Induced Pluripotent Stem Cells/drug effects
- Induced Pluripotent Stem Cells/metabolism
- Male
- Middle Aged
- Models, Biological
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Pedigree
- Receptors, Adrenergic, beta/metabolism
- Tachycardia, Ventricular/drug therapy
- Tachycardia, Ventricular/pathology
- Tachycardia, Ventricular/physiopathology
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Affiliation(s)
- Marcela K Preininger
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Rajneesh Jha
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Joshua T Maxwell
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Qingling Wu
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Monalisa Singh
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Bo Wang
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Aarti Dalal
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Zachary T Mceachin
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA Laboratory of Translational Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Wilfried Rossoll
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA Laboratory of Translational Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Chadwick M Hales
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Peter S Fischbach
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Mary B Wagner
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
| | - Chunhui Xu
- Division of Pediatric Cardiology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA
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