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Reisqs JB, Qu YS, Boutjdir M. Ion channel trafficking implications in heart failure. Front Cardiovasc Med 2024; 11:1351496. [PMID: 38420267 PMCID: PMC10899472 DOI: 10.3389/fcvm.2024.1351496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 01/25/2024] [Indexed: 03/02/2024] Open
Abstract
Heart failure (HF) is recognized as an epidemic in the contemporary world, impacting around 1%-2% of the adult population and affecting around 6 million Americans. HF remains a major cause of mortality, morbidity, and poor quality of life. Several therapies are used to treat HF and improve the survival of patients; however, despite these substantial improvements in treating HF, the incidence of HF is increasing rapidly, posing a significant burden to human health. The total cost of care for HF is USD 69.8 billion in 2023, warranting a better understanding of the mechanisms involved in HF. Among the most serious manifestations associated with HF is arrhythmia due to the electrophysiological changes within the cardiomyocyte. Among these electrophysiological changes, disruptions in sodium and potassium currents' function and trafficking, as well as calcium handling, all of which impact arrhythmia in HF. The mechanisms responsible for the trafficking, anchoring, organization, and recycling of ion channels at the plasma membrane seem to be significant contributors to ion channels dysfunction in HF. Variants, microtubule alterations, or disturbances of anchoring proteins lead to ion channel trafficking defects and the alteration of the cardiomyocyte's electrophysiology. Understanding the mechanisms of ion channels trafficking could provide new therapeutic approaches for the treatment of HF. This review provides an overview of the recent advances in ion channel trafficking in HF.
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Affiliation(s)
- Jean-Baptiste Reisqs
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
| | - Yongxia Sarah Qu
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
- Department of Cardiology, New York Presbyterian Brooklyn Methodist Hospital, New York, NY, United States
| | - Mohamed Boutjdir
- Cardiovascular Research Program, VA New York Harbor Healthcare System, New York, NY, United States
- Department of Medicine, Cell Biology and Pharmacology, State University of New York Downstate Health Sciences University, New York, NY, United States
- Department of Medicine, New York University Grossman School of Medicine, New York, NY, United States
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2
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Tarantino A, Ciconte G, Ghiroldi A, Mastrocinque F, Micaglio E, Boccellino A, Negro G, Piccoli M, Cirillo F, Vicedomini G, Santinelli V, Anastasia L, Pappone C. Challenges in Brugada Syndrome Stratification: Investigating SCN5A Mutation Localization and Clinical Phenotypes. Int J Mol Sci 2023; 24:16658. [PMID: 38068978 PMCID: PMC10706434 DOI: 10.3390/ijms242316658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/15/2023] [Accepted: 11/19/2023] [Indexed: 12/18/2023] Open
Abstract
Brugada Syndrome (BrS) is a genetic heart condition linked to sudden cardiac death. Though the SCN5A gene is primarily associated with BrS, there is a lack of comprehensive studies exploring the connection between SCN5A mutation locations and the clinical presentations of the syndrome. This study aimed to address this gap and gain further understanding of the syndrome. The investigation classified 36 high-risk BrS patients based on SCN5A mutations within the transmembrane/structured (TD) and intra-domain loops (IDLs) lacking a 3D structure. We characterized the intrinsically disordered regions (IDRs) abundant in IDLs, using bioinformatics tools to predict IDRs and post-translational modifications (PTMs) in NaV1.5. Interestingly, it was found that current predictive tools often underestimate the impacts of mutations in IDLs and disordered regions. Moreover, patients with SCN5A mutations confined to IDL regions-previously deemed 'benign'-displayed clinical symptoms similar to those carrying 'damaging' variants. Our research illuminates the difficulty in stratifying patients based on SCN5A mutation locations, emphasizing the vital role of IDLs in the NaV1.5 channel's functioning and protein interactions. We advocate for caution when using predictive tools for mutation evaluation in these regions and call for the development of improved strategies in accurately assessing BrS risk.
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Affiliation(s)
- Adriana Tarantino
- Institute for Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (A.T.); (M.P.); (F.C.)
- School of Medicine, University Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy;
| | - Giuseppe Ciconte
- School of Medicine, University Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy;
- Arrhythmology Department, IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (F.M.); (E.M.); (A.B.); (G.N.); (G.V.); (V.S.)
| | - Andrea Ghiroldi
- Institute for Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (A.T.); (M.P.); (F.C.)
| | - Flavio Mastrocinque
- Arrhythmology Department, IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (F.M.); (E.M.); (A.B.); (G.N.); (G.V.); (V.S.)
| | - Emanuele Micaglio
- Arrhythmology Department, IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (F.M.); (E.M.); (A.B.); (G.N.); (G.V.); (V.S.)
| | - Antonio Boccellino
- Arrhythmology Department, IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (F.M.); (E.M.); (A.B.); (G.N.); (G.V.); (V.S.)
| | - Gabriele Negro
- Arrhythmology Department, IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (F.M.); (E.M.); (A.B.); (G.N.); (G.V.); (V.S.)
| | - Marco Piccoli
- Institute for Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (A.T.); (M.P.); (F.C.)
| | - Federica Cirillo
- Institute for Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (A.T.); (M.P.); (F.C.)
| | - Gabriele Vicedomini
- Arrhythmology Department, IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (F.M.); (E.M.); (A.B.); (G.N.); (G.V.); (V.S.)
| | - Vincenzo Santinelli
- Arrhythmology Department, IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (F.M.); (E.M.); (A.B.); (G.N.); (G.V.); (V.S.)
| | - Luigi Anastasia
- Institute for Molecular and Translational Cardiology (IMTC), IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (A.T.); (M.P.); (F.C.)
- School of Medicine, University Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy;
| | - Carlo Pappone
- School of Medicine, University Vita-Salute San Raffaele, Via Olgettina 58, 20132 Milan, Italy;
- Arrhythmology Department, IRCCS Policlinico San Donato, Piazza Malan 2, San Donato Milanese, 20097 Milan, Italy; (F.M.); (E.M.); (A.B.); (G.N.); (G.V.); (V.S.)
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3
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Yoon JY, Greiner AM, Jacobs JS, Kim YR, Rasmussen TP, Kutschke WJ, Matasic DS, Vikram A, Gaddam RR, Mehdi H, Irani K, London B. SUMOylation of the cardiac sodium channel Na V1.5 modifies inward current and cardiac excitability. Heart Rhythm 2023; 20:1548-1557. [PMID: 37543305 DOI: 10.1016/j.hrthm.2023.07.067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 07/07/2023] [Accepted: 07/31/2023] [Indexed: 08/07/2023]
Abstract
BACKGROUND Decreased peak sodium current (INa) and increased late sodium current (INa,L), through the cardiac sodium channel NaV1.5 encoded by SCN5A, cause arrhythmias. Many NaV1.5 posttranslational modifications have been reported. A recent report concluded that acute hypoxia increases INa,L by increasing a small ubiquitin-like modifier (SUMOylation) at K442-NaV1.5. OBJECTIVE The purpose of this study was to determine whether and by what mechanisms SUMOylation alters INa, INa,L, and cardiac electrophysiology. METHODS SUMOylation of NaV1.5 was detected by immunoprecipitation and immunoblotting. INa was measured by patch clamp with/without SUMO1 overexpression in HEK293 cells expressing wild-type (WT) or K442R-NaV1.5 and in neonatal rat cardiac myocytes (NRCMs). SUMOylation effects were studied in vivo by electrocardiograms and ambulatory telemetry using Scn5a heterozygous knockout (SCN5A+/-) mice and the de-SUMOylating protein SENP2 (AAV9-SENP2), AAV9-SUMO1, or the SUMOylation inhibitor anacardic acid. NaV1.5 trafficking was detected by immunofluorescence. RESULTS NaV1.5 was SUMOylated in HEK293 cells, NRCMs, and human heart tissue. HyperSUMOylation at NaV1.5-K442 increased INa in NRCMs and in HEK cells overexpressing WT but not K442R-Nav1.5. SUMOylation did not alter other channel properties including INa,L. AAV9-SENP2 or anacardic acid decreased INa, prolonged QRS duration, and produced heart block and arrhythmias in SCN5A+/- mice, whereas AAV9-SUMO1 increased INa and shortened QRS duration. SUMO1 overexpression enhanced membrane localization of NaV1.5. CONCLUSION SUMOylation of K442-Nav1.5 increases peak INa without changing INa,L, at least in part by altering membrane abundance. Our findings do not support SUMOylation as a mechanism for changes in INa,L. Nav1.5 SUMOylation may modify arrhythmic risk in disease states and represents a potential target for pharmacologic manipulation.
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Affiliation(s)
- Jin-Young Yoon
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa; Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Alexander M Greiner
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Julia S Jacobs
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Young-Rae Kim
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Tyler P Rasmussen
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - William J Kutschke
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Daniel S Matasic
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Ajit Vikram
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa; Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Ravinder R Gaddam
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa; Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Haider Mehdi
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa; Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Kaikobad Irani
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa; Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa; Fraternal Order of Eagles Diabetes Research Center, Pappajohn Biomedical Institute, and Heart and Vascular Center, University of Iowa, Iowa City, Iowa.
| | - Barry London
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa, Iowa City, Iowa; Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa.
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4
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Sharma AK, Singh S, Bhat M, Gill K, Zaid M, Kumar S, Shakya A, Tantray J, Jose D, Gupta R, Yangzom T, Sharma RK, Sahu SK, Rathore G, Chandolia P, Singh M, Mishra A, Raj S, Gupta A, Agarwal M, Kifayat S, Gupta A, Gupta P, Vashist A, Vaibhav P, Kathuria N, Yadav V, Singh RP, Garg A. New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models. Sci Rep 2023; 13:16420. [PMID: 37775650 PMCID: PMC10541452 DOI: 10.1038/s41598-023-41942-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/04/2023] [Indexed: 10/01/2023] Open
Abstract
Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.
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Affiliation(s)
- Ashish Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India.
| | - Shivam Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mehvish Bhat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Kartik Gill
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohammad Zaid
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sachin Kumar
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anjali Shakya
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Junaid Tantray
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Divyamol Jose
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rashmi Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Tsering Yangzom
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rajesh Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | | | - Gulshan Rathore
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Priyanka Chandolia
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mithilesh Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anurag Mishra
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Shobhit Raj
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Archita Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohit Agarwal
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sumaiya Kifayat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anamika Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Prashant Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ankit Vashist
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Parth Vaibhav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Nancy Kathuria
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Vipin Yadav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ravindra Pal Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Arun Garg
- MVN University, Palwal, Haryana, India
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5
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Remme CA. SCN5A channelopathy: arrhythmia, cardiomyopathy, epilepsy and beyond. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220164. [PMID: 37122208 PMCID: PMC10150216 DOI: 10.1098/rstb.2022.0164] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 12/31/2022] [Indexed: 05/02/2023] Open
Abstract
Influx of sodium ions through voltage-gated sodium channels in cardiomyocytes is essential for proper electrical conduction within the heart. Both acquired conditions associated with sodium channel dysfunction (myocardial ischaemia, heart failure) as well as inherited disorders secondary to mutations in the gene SCN5A encoding for the cardiac sodium channel Nav1.5 are associated with life-threatening arrhythmias. Research in the last decade has uncovered the complex nature of Nav1.5 distribution, function, in particular within distinct subcellular subdomains of cardiomyocytes. Nav1.5-based channels furthermore display previously unrecognized non-electrogenic actions and may impact on cardiac structural integrity, leading to cardiomyopathy. Moreover, SCN5A and Nav1.5 are expressed in cell types other than cardiomyocytes as well as various extracardiac tissues, where their functional role in, e.g. epilepsy, gastrointestinal motility, cancer and the innate immune response is increasingly investigated and recognized. This review provides an overview of these novel insights and how they deepen our mechanistic knowledge on SCN5A channelopathies and Nav1.5 (dys)function. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- Carol Ann Remme
- Department of Experimental Cardiology, Heart Centre, Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam UMC location AMC, University of Amsterdam, Amsterdam, The Netherlands
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6
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Bersell KR, Yang T, Mosley JD, Glazer AM, Hale AT, Kryshtal DO, Kim K, Steimle JD, Brown JD, Salem JE, Campbell CC, Hong CC, Wells QS, Johnson AN, Short L, Blair MA, Behr ER, Petropoulou E, Jamshidi Y, Benson MD, Keyes MJ, Ngo D, Vasan RS, Yang Q, Gerszten RE, Shaffer C, Parikh S, Sheng Q, Kannankeril PJ, Moskowitz IP, York JD, Wang TJ, Knollmann BC, Roden DM. Transcriptional Dysregulation Underlies Both Monogenic Arrhythmia Syndrome and Common Modifiers of Cardiac Repolarization. Circulation 2023; 147:824-840. [PMID: 36524479 PMCID: PMC9992308 DOI: 10.1161/circulationaha.122.062193] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/03/2022] [Indexed: 12/23/2022]
Abstract
BACKGROUND Brugada syndrome (BrS) is an inherited arrhythmia syndrome caused by loss-of-function variants in the cardiac sodium channel gene SCN5A (sodium voltage-gated channel alpha subunit 5) in ≈20% of subjects. We identified a family with 4 individuals diagnosed with BrS harboring the rare G145R missense variant in the cardiac transcription factor TBX5 (T-box transcription factor 5) and no SCN5A variant. METHODS We generated induced pluripotent stem cells (iPSCs) from 2 members of a family carrying TBX5-G145R and diagnosed with Brugada syndrome. After differentiation to iPSC-derived cardiomyocytes (iPSC-CMs), electrophysiologic characteristics were assessed by voltage- and current-clamp experiments (n=9 to 21 cells per group) and transcriptional differences by RNA sequencing (n=3 samples per group), and compared with iPSC-CMs in which G145R was corrected by CRISPR/Cas9 approaches. The role of platelet-derived growth factor (PDGF)/phosphoinositide 3-kinase (PI3K) pathway was elucidated by small molecule perturbation. The rate-corrected QT (QTc) interval association with serum PDGF was tested in the Framingham Heart Study cohort (n=1893 individuals). RESULTS TBX5-G145R reduced transcriptional activity and caused multiple electrophysiologic abnormalities, including decreased peak and enhanced "late" cardiac sodium current (INa), which were entirely corrected by editing G145R to wild-type. Transcriptional profiling and functional assays in genome-unedited and -edited iPSC-CMs showed direct SCN5A down-regulation caused decreased peak INa, and that reduced PDGF receptor (PDGFRA [platelet-derived growth factor receptor α]) expression and blunted signal transduction to PI3K was implicated in enhanced late INa. Tbx5 regulation of the PDGF axis increased arrhythmia risk due to disruption of PDGF signaling and was conserved in murine model systems. PDGF receptor blockade markedly prolonged normal iPSC-CM action potentials and plasma levels of PDGF in the Framingham Heart Study were inversely correlated with the QTc interval (P<0.001). CONCLUSIONS These results not only establish decreased SCN5A transcription by the TBX5 variant as a cause of BrS, but also reveal a new general transcriptional mechanism of arrhythmogenesis of enhanced late sodium current caused by reduced PDGF receptor-mediated PI3K signaling.
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Affiliation(s)
- Kevin R Bersell
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Tao Yang
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Jonathan D Mosley
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Andrew M Glazer
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Andrew T Hale
- Biochemistry (A.T.H., J.D.Y.), Vanderbilt University, Nashville, TN
| | - Dmytro O Kryshtal
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Kyungsoo Kim
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Jeffrey D Steimle
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, IL (J.D.S., I.P.M.)
| | - Jonathan D Brown
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Joe-Elie Salem
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Assistance Publique - Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Department of Pharmacology, CIC-1901, Sorbonne University, Paris, France (J-E.S.)
- Sorbonne Universités, UPMC Univ Paris 06, Faculty of Medicine, France (J-E.S.)
| | - Courtney C Campbell
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Charles C Hong
- Department of Medicine, University of Maryland School of Medicine, Baltimore (C.C.H.)
| | - Quinn S Wells
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Biomedical Informatics (Q.S.W., D.M.R.), Vanderbilt University, Nashville, TN
| | - Amanda N Johnson
- Molecular Physiology and Biophysics (A.N.J.), Vanderbilt University, Nashville, TN
| | - Laura Short
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Marcia A Blair
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | | | - Evmorfia Petropoulou
- Cardiology Clinical Academic Group, Molecular and Clinical Sciences Institute, St George's, University of London and St George's University Hospitals National Health Service Foundation Trust, London, UK (E.P., Y.J.)
| | - Yalda Jamshidi
- Cardiology Clinical Academic Group, Molecular and Clinical Sciences Institute, St George's, University of London and St George's University Hospitals National Health Service Foundation Trust, London, UK (E.P., Y.J.)
| | - Mark D Benson
- Cardiovascular Research Center (E.J.B., M.D.B., M.J.K., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, MA (M.D.B.)
| | - Michelle J Keyes
- Cardiovascular Research Center (E.J.B., M.D.B., M.J.K., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
| | - Debby Ngo
- Division of Pulmonary and Cardiovascular Medicine (D.N., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
| | | | - Qiong Yang
- Boston University School of Medicine, MA (R.S.V., Q.Y.)
| | - Robert E Gerszten
- Cardiovascular Research Center (E.J.B., M.D.B., M.J.K., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
- Division of Pulmonary and Cardiovascular Medicine (D.N., R.E.G.), Beth Israel Deaconess Hospital, Boston, MA
| | - Christian Shaffer
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Shan Parikh
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | | | | | - Ivan P Moskowitz
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, IL (J.D.S., I.P.M.)
| | - John D York
- Biochemistry (A.T.H., J.D.Y.), Vanderbilt University, Nashville, TN
| | - Thomas J Wang
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Bjorn C Knollmann
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
| | - Dan M Roden
- Departments of Pharmacology (K.R.B., A.M.G., D.O.K., K.K., J-E.S., C.C.C., Q.S.W., S.P., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Medicine (T.Y., J.D.M., J.D.B., J-E.S., Q.S.W., L.S., M.A.B., C.S., T.J.W., B.C.K., D.M.R.), Vanderbilt University, Nashville, TN
- Biomedical Informatics (Q.S.W., D.M.R.), Vanderbilt University, Nashville, TN
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7
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Abdelsayed M, Page D, Ruben PC. ARumenamides: A novel class of potential antiarrhythmic compounds. Front Pharmacol 2022; 13:976903. [PMID: 36249789 PMCID: PMC9554508 DOI: 10.3389/fphar.2022.976903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/02/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Most therapeutics targeting cardiac voltage-gated sodium channels (Nav1.5) attenuate the sodium current (INa) conducted through the pore of the protein. Whereas these drugs may be beneficial for disease states associated with gain-of-function (GoF) in Nav1.5, few attempts have been made to therapeutically treat loss-of-function (LoF) conditions. The primary impediment to designing efficacious therapies for LoF is a tendency for drugs to occlude the Nav1.5 central pore. We hypothesized that molecular candidates with a high affinity for the fenestrations would potentially reduce pore block.Methods and Results: Virtual docking was performed on 21 compounds, selected based on their affinity for the fenestrations in Nav1.5, which included a class of sulfonamides and carboxamides we identify as ARumenamide (AR). Six ARs, AR-051, AR-189, AR-674, AR-802, AR-807 and AR-811, were further docked against Nav1.5 built on NavAb and rNav1.5. Based on the virtual docking results, these particular ARs have a high affinity for Domain III-IV and Domain VI-I fenestrations. Upon functional characterization, a trend was observed in the effects of the six ARs on INa. An inverse correlation was established between the aromaticity of the AR’s functional moieties and compound block. Due to its aromaticity, AR-811 blocked INa the least compared with other aromatic ARs, which also decelerated fast inactivation onset. AR-674, with its aliphatic functional group, significantly suppresses INa and enhances use-dependence in Nav1.5. AR-802 and AR-811, in particular, decelerated fast inactivation kinetics in the most common Brugada Syndrome Type 1 and Long-QT Syndrome Type 3 mutant, E1784K, without affecting peak or persistent INa.Conclusion: Our hypothesis that LoF in Nav1.5 may be therapeutically treated was supported by the discovery of ARs, which appear to preferentially block the fenestrations. ARs with aromatic functional groups as opposed to aliphatic groups efficaciously maintained Nav1.5 availability. We predict that these bulkier side groups may have a higher affinity for the hydrophobic milieu of the fenestrations, remaining there rather than in the central pore of the channel. Future refinements of AR compound structures and additional validation by molecular dynamic simulations and screening against more Brugada variants will further support their potential benefits in treating certain LoF cardiac arrhythmias.
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Affiliation(s)
- Mena Abdelsayed
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, United States
- Department of Medicine, Stanford University, Stanford, CA, United States
- *Correspondence: Mena Abdelsayed, ; Peter C. Ruben,
| | - Dana Page
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - Peter C. Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
- *Correspondence: Mena Abdelsayed, ; Peter C. Ruben,
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8
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Zybura AS, Sahoo FK, Hudmon A, Cummins TR. CaMKII Inhibition Attenuates Distinct Gain-of-Function Effects Produced by Mutant Nav1.6 Channels and Reduces Neuronal Excitability. Cells 2022; 11:2108. [PMID: 35805192 PMCID: PMC9266207 DOI: 10.3390/cells11132108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/16/2022] [Accepted: 06/27/2022] [Indexed: 11/17/2022] Open
Abstract
Aberrant Nav1.6 activity can induce hyperexcitability associated with epilepsy. Gain-of-function mutations in the SCN8A gene encoding Nav1.6 are linked to epilepsy development; however, the molecular mechanisms mediating these changes are remarkably heterogeneous and may involve post-translational regulation of Nav1.6. Because calcium/calmodulin-dependent protein kinase II (CaMKII) is a powerful modulator of Nav1.6 channels, we investigated whether CaMKII modulates disease-linked Nav1.6 mutants. Whole-cell voltage clamp recordings in ND7/23 cells show that CaMKII inhibition of the epilepsy-related mutation R850Q largely recapitulates the effects previously observed for WT Nav1.6. We also characterized a rare missense variant, R639C, located within a regulatory hotspot for CaMKII modulation of Nav1.6. Prediction software algorithms and electrophysiological recordings revealed gain-of-function effects for R639C mutant channel activity, including increased sodium currents and hyperpolarized activation compared to WT Nav1.6. Importantly, the R639C mutation ablates CaMKII phosphorylation at a key regulatory site, T642, and, in contrast to WT and R850Q channels, displays a distinct response to CaMKII inhibition. Computational simulations demonstrate that modeled neurons harboring the R639C or R850Q mutations are hyperexcitable, and simulating the effects of CaMKII inhibition on Nav1.6 activity in modeled neurons differentially reduced hyperexcitability. Acute CaMKII inhibition may represent a promising mechanism to attenuate gain-of-function effects produced by Nav1.6 mutations.
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Affiliation(s)
- Agnes S. Zybura
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
| | - Firoj K. Sahoo
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (F.K.S.); (A.H.)
| | - Andy Hudmon
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; (F.K.S.); (A.H.)
| | - Theodore R. Cummins
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
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9
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Blackwell DJ, Schmeckpeper J, Knollmann BC. Animal Models to Study Cardiac Arrhythmias. Circ Res 2022; 130:1926-1964. [PMID: 35679367 DOI: 10.1161/circresaha.122.320258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.
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Affiliation(s)
- Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Schmeckpeper
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
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10
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Cervantes DO, Pizzo E, Ketkar H, Parambath SP, Tang S, Cianflone E, Cannata A, Vinukonda G, Jain S, Jacobson JT, Rota M. Scn1b expression in the adult mouse heart modulates Na + influx in myocytes and reveals a mechanistic link between Na + entry and diastolic function. Am J Physiol Heart Circ Physiol 2022; 322:H975-H993. [PMID: 35394857 PMCID: PMC9076421 DOI: 10.1152/ajpheart.00465.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 03/09/2022] [Accepted: 03/23/2022] [Indexed: 11/22/2022]
Abstract
Voltage-gated sodium channels (VGSCs) are macromolecular assemblies composed of a number of proteins regulating channel conductance and properties. VGSCs generate Na+ current (INa) in myocytes and play fundamental roles in excitability and impulse conduction in the heart. Moreover, VGSCs condition mechanical properties of the myocardium, a process that appears to involve the late component of INa. Variants in the gene SCN1B, encoding the VGSC β1- and β1B-subunits, result in inherited neurological disorders and cardiac arrhythmias. But the precise contributions of β1/β1B-subunits and VGSC integrity to the overall function of the adult heart remain to be clarified. For this purpose, adult mice with cardiac-restricted, inducible deletion of Scn1b (conditional knockout, cKO) were studied. Myocytes from cKO mice had increased densities of fast (+20%)- and slow (+140%)-inactivating components of INa, with respect to control cells. By echocardiography and invasive hemodynamics, systolic function was preserved in cKO mice, but diastolic properties and ventricular compliance were compromised, with respect to control animals. Importantly, inhibition of late INa with GS967 normalized left ventricular filling pattern and isovolumic relaxation time in cKO mice. At the cellular level, cKO myocytes presented delayed kinetics of Ca2+ transients and cell mechanics, defects that were corrected by inhibition of INa. Collectively, these results document that VGSC β1/β1B-subunits modulate electrical and mechanical function of the heart by regulating, at least in part, Na+ influx in cardiomyocytes.NEW & NOTEWORTHY We have investigated the consequences of deletion of Scn1b, the gene encoding voltage-gated sodium channel β1-subunits, on myocyte and cardiac function. Our findings support the notion that Scn1b expression controls properties of Na+ influx and Ca2+ cycling in cardiomyocytes affecting the modality of cell contraction and relaxation. These effects at the cellular level condition electrical recovery and diastolic function in vivo, substantiating the multifunctional role of β1-subunits in the physiology of the heart.
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Affiliation(s)
| | - Emanuele Pizzo
- Department of Physiology, New York Medical College, Valhalla, New York
| | - Harshada Ketkar
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, New York
| | - Sreema P Parambath
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, New York
| | - Samantha Tang
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, New York
| | - Eleonora Cianflone
- Department of Physiology, New York Medical College, Valhalla, New York
- Molecular and Cellular Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy
| | - Antonio Cannata
- School of Cardiovascular Medicine and Sciences, King's College London British Heart Foundation Centre of Excellence, London, United Kingdom
| | | | - Sudhir Jain
- Department of Pathology, Microbiology and Immunology, New York Medical College, Valhalla, New York
| | - Jason T Jacobson
- Department of Physiology, New York Medical College, Valhalla, New York
- Department of Cardiology, Westchester Medical Center, Valhalla, New York
| | - Marcello Rota
- Department of Physiology, New York Medical College, Valhalla, New York
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11
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Absolute Quantification of Nav1.5 Expression by Targeted Mass Spectrometry. Int J Mol Sci 2022; 23:ijms23084177. [PMID: 35456996 PMCID: PMC9028338 DOI: 10.3390/ijms23084177] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 11/20/2022] Open
Abstract
Nav1.5 is the pore forming α-subunit of the cardiac voltage-gated sodium channel that initiates cardiac action potential and regulates the human heartbeat. A normal level of Nav1.5 is crucial to cardiac function and health. Over- or under-expression of Nav1.5 can cause various cardiac diseases ranging from short PR intervals to Brugada syndromes. An assay that can directly quantify the protein amount in biological samples would be a priori to accurately diagnose and treat Nav1.5-associated cardiac diseases. Due to its large size (>200 KD), multipass transmembrane domains (24 transmembrane passes), and heavy modifications, Nav1.5 poses special quantitation challenges. To date, only the relative quantities of this protein have been measured in biological samples. Here, we describe the first targeted and mass spectrometry (MS)-based quantitative assay that can provide the copy numbers of Nav1.5 in cells with a well-defined lower limit of quantification (LLOQ) and precision. Applying the developed assay, we successfully quantified transiently expressed Nav1.5 in as few as 1.5 million Chinese hamster ovary (CHO) cells. The obtained quantity was 3 ± 2 fmol on the column and 3 ± 2 × 104 copies/cell. To our knowledge, this is the first absolute quantity of Nav1.5 measured in a biological sample.
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12
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Horváth B, Szentandrássy N, Almássy J, Dienes C, Kovács ZM, Nánási PP, Banyasz T. Late Sodium Current of the Heart: Where Do We Stand and Where Are We Going? Pharmaceuticals (Basel) 2022; 15:ph15020231. [PMID: 35215342 PMCID: PMC8879921 DOI: 10.3390/ph15020231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 02/05/2023] Open
Abstract
Late sodium current has long been linked to dysrhythmia and contractile malfunction in the heart. Despite the increasing body of accumulating information on the subject, our understanding of its role in normal or pathologic states is not complete. Even though the role of late sodium current in shaping action potential under physiologic circumstances is debated, it’s unquestioned role in arrhythmogenesis keeps it in the focus of research. Transgenic mouse models and isoform-specific pharmacological tools have proved useful in understanding the mechanism of late sodium current in health and disease. This review will outline the mechanism and function of cardiac late sodium current with special focus on the recent advances of the area.
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Affiliation(s)
- Balázs Horváth
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Norbert Szentandrássy
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
- Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, 4032 Debrecen, Hungary
| | - János Almássy
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Csaba Dienes
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Zsigmond Máté Kovács
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Péter P. Nánási
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
- Department of Dental Physiology and Pharmacology, University of Debrecen, 4032 Debrecen, Hungary
| | - Tamas Banyasz
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
- Correspondence: ; Tel.: +36-(52)-255-575; Fax: +36-(52)-255-116
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13
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Daimi H, Lozano-Velasco E, Aranega A, Franco D. Genomic and Non-Genomic Regulatory Mechanisms of the Cardiac Sodium Channel in Cardiac Arrhythmias. Int J Mol Sci 2022; 23:1381. [PMID: 35163304 PMCID: PMC8835759 DOI: 10.3390/ijms23031381] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/30/2021] [Accepted: 01/06/2022] [Indexed: 12/19/2022] Open
Abstract
Nav1.5 is the predominant cardiac sodium channel subtype, encoded by the SCN5A gene, which is involved in the initiation and conduction of action potentials throughout the heart. Along its biosynthesis process, Nav1.5 undergoes strict genomic and non-genomic regulatory and quality control steps that allow only newly synthesized channels to reach their final membrane destination and carry out their electrophysiological role. These regulatory pathways are ensured by distinct interacting proteins that accompany the nascent Nav1.5 protein along with different subcellular organelles. Defects on a large number of these pathways have a tremendous impact on Nav1.5 functionality and are thus intimately linked to cardiac arrhythmias. In the present review, we provide current state-of-the-art information on the molecular events that regulate SCN5A/Nav1.5 and the cardiac channelopathies associated with defects in these pathways.
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Affiliation(s)
- Houria Daimi
- Biochemistry and Molecular Biology Laboratory, Faculty of Pharmacy, University of Monastir, Monastir 5000, Tunisia
| | - Estefanía Lozano-Velasco
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
| | - Amelia Aranega
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
| | - Diego Franco
- Department of Experimental Biology, University of Jaen, 23071 Jaen, Spain; (E.L.-V.); (A.A.); (D.F.)
- Medina Foundation, Technology Park of Health Sciences, Av. del Conocimiento, 34, 18016 Granada, Spain
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14
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Zhong C, Zhao H, Xie X, Qi Z, Li Y, Jia L, Zhang J, Lu Y. Protein Kinase C-Mediated Hyperphosphorylation and Lateralization of Connexin 43 Are Involved in Autoimmune Myocarditis-Induced Prolongation of QRS Complex. Front Physiol 2022; 13:815301. [PMID: 35418879 PMCID: PMC9000987 DOI: 10.3389/fphys.2022.815301] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/25/2022] [Indexed: 02/05/2023] Open
Abstract
Myocarditis is a serious and potentially life-threatening disease, which leads to cardiac dysfunction and sudden cardiac death. An increasing number of evidence suggests that myocarditis is also a malignant complication of coronavirus pneumonia, associated with heart failure and sudden cardiac death. Prolonged QRS complexes that are related to malignant arrhythmias caused by myocarditis significantly increase the risk of sudden cardiac death in patients. However, the molecular mechanisms are not fully known at present. In this study, we identify protein kinase C (PKC) as a new regulator of the QRS complex. In isolated hearts of normal rats, the PKC agonist, phorbol-12-myristate-13-acetate (PMA), induced prolongation of the QRS complex. Mechanistically, hyperphosphorylation and lateralization of connexin 43 (Cx43) by PKC induced depolymerization and internalization of Cx43 gap junction channels and prolongation of the QRS duration. Conversely, administration of the PKC inhibitor, Ro-32-0432, in experimental autoimmune myocarditis (EAM) rats after the most severe inflammation period still significantly rescued the stability of the Cx43 gap junction and alleviated prolongation of the QRS complex. Ro-32-0432 reduced phosphorylation and blocked translocation of Cx43 in EAM rat heart but did not regulate the mRNA expression level of ventricular ion channels and the other regulatory proteins, which indicates that the inhibition of PKC might have no protective effect on ion channels that generate ventricular action potential in EAM rats. These results suggest that the pharmacological inhibition of PKC ameliorates the prolongation of the QRS complex via suppression of Cx43 hyperphosphorylation, lateralization, and depolymerization of Cx43 gap junction channels in EAM rats, which provides a potential therapeutic strategy for myocarditis-induced arrhythmias.
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Affiliation(s)
- Chunlian Zhong
- School of Material and Chemical Engineering, Minjiang University, Fuzhou, China
- Fuzhou Institute of Oceanography, Fuzhou, China
| | - Huan Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Sciences, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, China
| | - Xinwen Xie
- Liancheng County General Hospital, Longyan, China
| | - Zhi Qi
- Department of Basic Medical Sciences, Medical College of Xiamen University, Xiamen, China
| | - Yumei Li
- School of Basic Medicine, Gannan Medical University, Ganzhou, China
| | - Lee Jia
- School of Material and Chemical Engineering, Minjiang University, Fuzhou, China
- Fuzhou Institute of Oceanography, Fuzhou, China
- *Correspondence: Lee Jia, ,
| | - Jinwei Zhang
- Xiamen Key Laboratory of Cardiovascular Disease, Xiamen Cardiovascular Hospital Xiamen University, Xiamen, China
- Hatherly Laboratories, Medical School, College of Medicine and Health, Institute of Biomedical and Clinical Sciences, University of Exeter, Exeter, United Kingdom
- Jinwei Zhang,
| | - Yusheng Lu
- School of Material and Chemical Engineering, Minjiang University, Fuzhou, China
- Fuzhou Institute of Oceanography, Fuzhou, China
- Yusheng Lu, ,
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15
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van Weperen VYH, Vos MA, Ajijola OA. Autonomic modulation of ventricular electrical activity: recent developments and clinical implications. Clin Auton Res 2021; 31:659-676. [PMID: 34591191 PMCID: PMC8629778 DOI: 10.1007/s10286-021-00823-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/12/2021] [Indexed: 12/19/2022]
Abstract
PURPOSE This review aimed to provide a complete overview of the current stance and recent developments in antiarrhythmic neuromodulatory interventions, focusing on lifethreatening vetricular arrhythmias. METHODS Both preclinical studies and clinical studies were assessed to highlight the gaps in knowledge that remain to be answered and the necessary steps required to properly translate these strategies to the clinical setting. RESULTS Cardiac autonomic imbalance, characterized by chronic sympathoexcitation and parasympathetic withdrawal, destabilizes cardiac electrophysiology and promotes ventricular arrhythmogenesis. Therefore, neuromodulatory interventions that target the sympatho-vagal imbalance have emerged as promising antiarrhythmic strategies. These strategies are aimed at different parts of the cardiac neuraxis and directly or indirectly restore cardiac autonomic tone. These interventions include pharmacological blockade of sympathetic neurotransmitters and neuropeptides, cardiac sympathetic denervation, thoracic epidural anesthesia, and spinal cord and vagal nerve stimulation. CONCLUSION Neuromodulatory strategies have repeatedly been demonstrated to be highly effective and very promising anti-arrhythmic therapies. Nevertheless, there is still much room to gain in our understanding of neurocardiac physiology, refining the current neuromodulatory strategic options and elucidating the chronic effects of many of these strategic options.
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Affiliation(s)
- Valerie Y H van Weperen
- Department of Medical Physiology, Universitair Medisch Centrum Utrecht, Utrecht, The Netherlands
- UCLA Cardiac Arrhythmia Center, UCLA Neurocardiology Research Center, UCLA Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, University of California, 100 Medical Plaza, Suite 660, Westwood Blvd, Los Angeles, CA, 90095-1679, USA
| | - Marc A Vos
- Department of Medical Physiology, Universitair Medisch Centrum Utrecht, Utrecht, The Netherlands
| | - Olujimi A Ajijola
- UCLA Cardiac Arrhythmia Center, UCLA Neurocardiology Research Center, UCLA Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, University of California, 100 Medical Plaza, Suite 660, Westwood Blvd, Los Angeles, CA, 90095-1679, USA.
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16
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D'Imperio S, Monasky MM, Micaglio E, Ciconte G, Anastasia L, Pappone C. Brugada Syndrome: Warning of a Systemic Condition? Front Cardiovasc Med 2021; 8:771349. [PMID: 34722688 PMCID: PMC8553994 DOI: 10.3389/fcvm.2021.771349] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 09/23/2021] [Indexed: 12/19/2022] Open
Abstract
Brugada syndrome (BrS) is a hereditary disorder, characterized by a specific electrocardiogram pattern and highly related to an increased risk of sudden cardiac death. BrS has been associated with other cardiac and non-cardiac pathologies, probably because of protein expression shared by the heart and other tissue types. In fact, the most commonly found mutated gene in BrS, SCN5A, is expressed throughout nearly the entire body. Consistent with this, large meals and alcohol consumption can trigger arrhythmic events in patients with BrS, suggesting a role for organs involved in the digestive and metabolic pathways. Ajmaline, a drug used to diagnose BrS, can have side effects on non-cardiac tissues, such as the liver, further supporting the idea of a role for organs involved in the digestive and metabolic pathways in BrS. The BrS electrocardiogram (ECG) sign has been associated with neural, digestive, and metabolic pathways, and potential biomarkers for BrS have been found in the serum or plasma. Here, we review the known associations between BrS and various organ systems, and demonstrate support for the hypothesis that BrS is not only a cardiac disorder, but rather a systemic one that affects virtually the whole body. Any time that the BrS ECG sign is found, it should be considered not a single disease, but rather the final step in any number of pathways that ultimately threaten the patient's life. A multi-omics approach would be appropriate to study this syndrome, including genetics, epigenomics, transcriptomics, proteomics, metabolomics, lipidomics, and glycomics, resulting eventually in a biomarker for BrS and the ability to diagnose this syndrome using a minimally invasive blood test, avoiding the risk associated with ajmaline testing.
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Affiliation(s)
- Sara D'Imperio
- Arrhythmology Department, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico San Donato, Milan, Italy
| | - Michelle M Monasky
- Arrhythmology Department, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico San Donato, Milan, Italy
| | - Emanuele Micaglio
- Arrhythmology Department, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico San Donato, Milan, Italy
| | - Giuseppe Ciconte
- Arrhythmology Department, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico San Donato, Milan, Italy
| | - Luigi Anastasia
- Faculty of Medicine and Surgery, University of Vita-Salute San Raffaele, Milan, Italy
| | - Carlo Pappone
- Arrhythmology Department, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico San Donato, Milan, Italy.,Faculty of Medicine and Surgery, University of Vita-Salute San Raffaele, Milan, Italy
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17
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Sakla M, Breitinger U, Breitinger HG, Mansour S, Tammam SN. Delivery of trans-membrane proteins by liposomes; the effect of liposome size and formulation technique on the efficiency of protein delivery. Int J Pharm 2021; 606:120879. [PMID: 34265391 DOI: 10.1016/j.ijpharm.2021.120879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 06/29/2021] [Accepted: 07/09/2021] [Indexed: 01/06/2023]
Abstract
Channelopathies are disorders caused by reduced expression or impaired function of ion channels. Most current therapies rely on symptomatic treatment without addressing the underlying cause. We have recently established proof of principle for delivery of functional ion channel protein into the membrane of target cells using fusogenic liposomes incorporating glycine receptor (GlyR)-containing cell membrane fragments (CMF) that were formulated by thin film hydration. Here, the effect of liposome size and the formulation technique on the performance of the delivery vehicle was assessed. Three types of liposomes were prepared using lecithin and cholesterol, (i) small (SL), and (ii) large (LL) liposomes made by thin film hydration, and (iii) small liposomes prepared by vortex agitation (V-SL). All liposomes were evaluated for their ability to (i) incorporate GlyR-rich CMF, (ii) fuse with the cell membrane of target cells and (iii) deliver functional GlyR, as assessed by patch-clamp electrophysiology. SL prepared by thin film hydration offered the most effective delivery of glycine receptors that gave clear glycine-mediated currents in target cells. LL showed higher incorporation of CMF, but did not effectively fuse with the target cell membrane, while V-SL did not incorporate sufficient amounts of CMF. Additionally, SL showed minimalin vivotoxicity upon intrathecal injection in mice. Thus, liposome-mediated delivery of membrane proteins may be a promising therapeutic approach for the treatment of channelopathies.
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Affiliation(s)
- Monica Sakla
- Department of Pharmaceutical Technology, The German University in Cairo (GUC), Cairo, Egypt
| | - Ulrike Breitinger
- Department of Biochemistry, The German University in Cairo (GUC), Cairo, Egypt
| | | | - Samar Mansour
- Department of Pharmaceutical Technology, The German University in Cairo (GUC), Cairo, Egypt
| | - Salma N Tammam
- Department of Pharmaceutical Technology, The German University in Cairo (GUC), Cairo, Egypt.
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18
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Zybura A, Hudmon A, Cummins TR. Distinctive Properties and Powerful Neuromodulation of Na v1.6 Sodium Channels Regulates Neuronal Excitability. Cells 2021; 10:cells10071595. [PMID: 34202119 PMCID: PMC8307729 DOI: 10.3390/cells10071595] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/20/2021] [Accepted: 06/21/2021] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (Navs) are critical determinants of cellular excitability. These ion channels exist as large heteromultimeric structures and their activity is tightly controlled. In neurons, the isoform Nav1.6 is highly enriched at the axon initial segment and nodes, making it critical for the initiation and propagation of neuronal impulses. Changes in Nav1.6 expression and function profoundly impact the input-output properties of neurons in normal and pathological conditions. While mutations in Nav1.6 may cause channel dysfunction, aberrant changes may also be the result of complex modes of regulation, including various protein-protein interactions and post-translational modifications, which can alter membrane excitability and neuronal firing properties. Despite decades of research, the complexities of Nav1.6 modulation in health and disease are still being determined. While some modulatory mechanisms have similar effects on other Nav isoforms, others are isoform-specific. Additionally, considerable progress has been made toward understanding how individual protein interactions and/or modifications affect Nav1.6 function. However, there is still more to be learned about how these different modes of modulation interact. Here, we examine the role of Nav1.6 in neuronal function and provide a thorough review of this channel’s complex regulatory mechanisms and how they may contribute to neuromodulation.
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Affiliation(s)
- Agnes Zybura
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Andy Hudmon
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA;
| | - Theodore R. Cummins
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
- Correspondence:
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19
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Nieto-Marín P, Tinaquero D, Utrilla RG, Cebrián J, González-Guerra A, Crespo-García T, Cámara-Checa A, Rubio-Alarcón M, Dago M, Alfayate S, Filgueiras D, Peinado R, López-Sendón JL, Jalife J, Tamargo J, Bernal JA, Caballero R, Delpón E. Tbx5 variants disrupt Nav1.5 function differently in patients diagnosed with Brugada or Long QT Syndrome. Cardiovasc Res 2021; 118:1046-1060. [PMID: 33576403 DOI: 10.1093/cvr/cvab045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/22/2020] [Accepted: 02/04/2021] [Indexed: 12/14/2022] Open
Abstract
AIMS The transcription factor Tbx5 controls cardiogenesis and drives Scn5a expression in mice. We have identified two variants in TBX5 encoding p.D111Y and p.F206L Tbx5, respectively, in two unrelated patients with structurally normal hearts diagnosed with Long QT (LQTS) and Brugada (BrS) Syndrome. Here we characterized the consequences of each variant to unravel the underlying disease mechanisms. METHODS AND RESULTS We combined clinical analysis with in vivo and in vitro electrophysiological and molecular techniques in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), HL-1 cells, and cardiomyocytes from mice trans-expressing human wildtype (WT) or mutant proteins. Tbx5 increased transcription of SCN5A encoding cardiac Nav1.5 channels, while repressing CAMK2D and SPTBN4 genes encoding Ca-calmodulin kinase IIδ (CaMKIIδ) and βIV-spectrin, respectively. These effects significantly increased Na current (INa) in hiPSC-CMs and in cardiomyocytes from mice trans-expressing Tbx5. Consequently, action potential (AP) amplitudes increased and QRS interval narrowed in the mouse electrocardiogram. p.F206L Tbx5 bound to the SCN5A promoter failed to transactivate it, thus precluding the pro-transcriptional effect of WT Tbx5. Therefore, p.F206L markedly decreased INa in hiPSC-CM, HL-1 cells, and mouse cardiomyocytes. The INa decrease in p.F206L trans-expressing mice translated into QRS widening and increased flecainide sensitivity. p.D111Y Tbx5 increased SCN5A expression but failed to repress CAMK2D and SPTBN4. The increased CaMKIIδ and βIV-spectrin significantly augmented the late component of INa (INaL) which, in turn, significantly prolonged AP duration in both hiPSC-CMs and mouse cardiomyocytes. Ranolazine, a selective INaL inhibitor, eliminated the QT and QTc intervals prolongation seen in p.D111Y trans-expressing mice. CONCLUSIONS In addition to peak INa, Tbx5 critically regulates INaL and the duration of repolarization in human cardiomyocytes. Our original results suggest that TBX5 variants associate with and modulate the intensity of the electrical phenotype in LQTS and BrS patients.
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Affiliation(s)
- Paloma Nieto-Marín
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - David Tinaquero
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Raquel G Utrilla
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Jorge Cebrián
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | | | - Teresa Crespo-García
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Anabel Cámara-Checa
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Marcos Rubio-Alarcón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - María Dago
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Silvia Alfayate
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - David Filgueiras
- Fundación Centro Nacional de Investigaciones Cardiovasculares. 28029-Madrid, Spain
| | - Rafael Peinado
- Department of Cardiology. Hospital Universitario La Paz. Instituto de Investigación Sanitaria la Paz. 28046-Madrid Spain
| | - José Luis López-Sendón
- Department of Cardiology. Hospital Universitario La Paz. Instituto de Investigación Sanitaria la Paz. 28046-Madrid Spain
| | - José Jalife
- Fundación Centro Nacional de Investigaciones Cardiovasculares. 28029-Madrid, Spain.,Departments of Internal Medicine and Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Juan Tamargo
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Juan Antonio Bernal
- Fundación Centro Nacional de Investigaciones Cardiovasculares. 28029-Madrid, Spain
| | - Ricardo Caballero
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
| | - Eva Delpón
- Department of Pharmacology and Toxicology. School of Medicine. Universidad Complutense de Madrid. Instituto de Investigación Gregorio Marañón. CIBERCV. 28040-Madrid, Spain
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20
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Ubiquitination-activating enzymes UBE1 and UBA6 regulate ubiquitination and expression of cardiac sodium channel Nav1.5. Biochem J 2020; 477:1683-1700. [PMID: 32315024 DOI: 10.1042/bcj20200138] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 04/18/2020] [Accepted: 04/21/2020] [Indexed: 12/26/2022]
Abstract
Cardiac sodium channel Nav1.5 is associated with cardiac arrhythmias and heart failure. Protein ubiquitination is catalyzed by an E1-E2-E3 cascade of enzymes. However, the E1 enzyme catalyzing Nav1.5 ubiquitination is unknown. Here, we show that UBE1 and UBA6 are two E1 enzymes regulating Nav1.5 ubiquitination and expression. Western blot analysis and patch-clamping recordings showed that overexpression of UBE1 or UBA6 increased the ubiquitination of Nav1.5 and significantly reduced Nav1.5 expression and sodium current density, and knockdown of UBE1 or UBA6 expression significantly increased Nav1.5 expression and sodium current density in HEK293/Nav1.5 cells. Similar results were obtained in neonatal cardiomyocytes. Bioinformatic analysis predicted two ubiquitination sites at K590 and K591. Mutations of K590 and K591 to K590A and K591A abolished the effects of overexpression or knockdown of UBE1 or UBA6 on Nav1.5 expression and sodium current density. Western blot analysis showed that the effects of UBE1 or UBA6 overexpression on the ubiquitination and expression of Nav1.5 were abolished by knockdown of UBC9, a putative E2 enzyme reported for Nav1.5 ubiquitination by us. Interestingly, real-time RT-PCR analysis showed that the expression level of UBE1, but not UBA6, was significantly up-regulated in ventricular tissues from heart failure patients. These data establish UBE1 and UBA6 as the E1 enzymes involved in Nav1.5 ubiquitination, and suggest that UBE1 and UBA6 regulate ubiquitination of Nav1.5 through UBC9. Our study is the first to reveal the regulatory role of the UBE1 or UBA6 E1 enzyme in the ubiquitination of an ion channel and links UBE1 up-regulation to heart failure.
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21
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Kang GJ, Xie A, Liu H, Dudley SC. MIR448 antagomir reduces arrhythmic risk after myocardial infarction by upregulating the cardiac sodium channel. JCI Insight 2020; 5:140759. [PMID: 33108349 PMCID: PMC7714400 DOI: 10.1172/jci.insight.140759] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/21/2020] [Indexed: 12/17/2022] Open
Abstract
Cardiac ischemia is associated with arrhythmias; however, effective therapies are currently limited. The cardiac voltage-gated sodium channel α subunit (SCN5A), encoding the Nav1.5 current, plays a key role in the cardiac electrical conduction and arrhythmic risk. Here, we show that hypoxia reduces Nav1.5 through effects on a miR, miR-448. miR-448 expression is increased in ischemic cardiomyopathy. miR-448 has a conserved binding site in 3′-UTR of SCN5A. miR-448 binding to this site suppressed SCN5A expression and sodium currents. Hypoxia-induced HIF-1α and NF-κB were major transcriptional regulators for MIR448. Moreover, hypoxia relieved MIR448 transcriptional suppression by RE1 silencing transcription factor. Therefore, miR-448 inhibition reduced arrhythmic risk after myocardial infarction. Here, we show that ischemia drove miR-448 expression, reduced Nav1.5 current, and increased arrhythmic risk. Arrhythmic risk was improved by preventing Nav1.5 downregulation, suggesting a new approach to antiarrhythmic therapy. Ischemic induction of miR-448 negatively regulates the cardiac sodium channel Nav1.5, and inhibiting miR-448 raises Nav1.5 and reduces arrhythmic risk after myocardial infarction in mice.
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22
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Zybura AS, Baucum AJ, Rush AM, Cummins TR, Hudmon A. CaMKII enhances voltage-gated sodium channel Nav1.6 activity and neuronal excitability. J Biol Chem 2020; 295:11845-11865. [PMID: 32611770 DOI: 10.1074/jbc.ra120.014062] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/30/2020] [Indexed: 11/06/2022] Open
Abstract
Nav1.6 is the primary voltage-gated sodium channel isoform expressed in mature axon initial segments and nodes, making it critical for initiation and propagation of neuronal impulses. Thus, Nav1.6 modulation and dysfunction may have profound effects on input-output properties of neurons in normal and pathological conditions. Phosphorylation is a powerful and reversible mechanism regulating ion channel function. Because Nav1.6 and the multifunctional Ca2+/CaM-dependent protein kinase II (CaMKII) are independently linked to excitability disorders, we sought to investigate modulation of Nav1.6 function by CaMKII signaling. We show that inhibition of CaMKII, a Ser/Thr protein kinase associated with excitability, synaptic plasticity, and excitability disorders, with the CaMKII-specific peptide inhibitor CN21 reduces transient and persistent currents in Nav1.6-expressing Purkinje neurons by 87%. Using whole-cell voltage clamp of Nav1.6, we show that CaMKII inhibition in ND7/23 and HEK293 cells significantly reduces transient and persistent currents by 72% and produces a 5.8-mV depolarizing shift in the voltage dependence of activation. Immobilized peptide arrays and nanoflow LC-electrospray ionization/MS of Nav1.6 reveal potential sites of CaMKII phosphorylation, specifically Ser-561 and Ser-641/Thr-642 within the first intracellular loop of the channel. Using site-directed mutagenesis to test multiple potential sites of phosphorylation, we show that Ala substitutions of Ser-561 and Ser-641/Thr-642 recapitulate the depolarizing shift in activation and reduction in current density. Computational simulations to model effects of CaMKII inhibition on Nav1.6 function demonstrate dramatic reductions in spontaneous and evoked action potentials in a Purkinje cell model, suggesting that CaMKII modulation of Nav1.6 may be a powerful mechanism to regulate neuronal excitability.
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Affiliation(s)
- Agnes S Zybura
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Anthony J Baucum
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Biology Department, Indiana University-Purdue University Indianapolis, School of Science, Indianapolis, Indiana, USA
| | | | - Theodore R Cummins
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA.,Biology Department, Indiana University-Purdue University Indianapolis, School of Science, Indianapolis, Indiana, USA
| | - Andy Hudmon
- Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, Indiana, USA .,Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
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23
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Takla M, Huang CLH, Jeevaratnam K. The cardiac CaMKII-Na v1.5 relationship: From physiology to pathology. J Mol Cell Cardiol 2020; 139:190-200. [PMID: 31958466 DOI: 10.1016/j.yjmcc.2019.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/20/2019] [Accepted: 12/30/2019] [Indexed: 12/19/2022]
Abstract
The SCN5A gene encodes Nav1.5, which, as the cardiac voltage-gated Na+ channel's pore-forming α subunit, is crucial for the initiation and propagation of atrial and ventricular action potentials. The arrhythmogenic propensity of inherited SCN5A mutations implicates the Na+ channel in determining cardiomyocyte excitability under normal conditions. Cytosolic kinases have long been known to alter the kinetic profile of Nav1.5 inactivation via phosphorylation of specific residues. Recent substantiation of both the role of calmodulin-dependent kinase II (CaMKII) in modulating the properties of the Nav1.5 inactivation gate and the significant rise in oxidation-dependent autonomous CaMKII activity in structural heart disease has raised the possibility of a novel pathway for acquired arrhythmias - the CaMKII-Nav1.5 relationship. The aim of this review is to: (1) outline the relationship's translation from physiological adaptation to pathological vicious circle; and (2) discuss the relative merits of each of its components as pharmacological targets.
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Affiliation(s)
- Michael Takla
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, United Kingdom
| | - Christopher L-H Huang
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, United Kingdom; Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7AL, United Kingdom; Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, United Kingdom.
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24
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Grandi E, Ripplinger CM. Antiarrhythmic mechanisms of beta blocker therapy. Pharmacol Res 2019; 146:104274. [PMID: 31100336 DOI: 10.1016/j.phrs.2019.104274] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 05/04/2019] [Accepted: 05/13/2019] [Indexed: 02/07/2023]
Abstract
Sympathetic activity plays an important role in modulation of cardiac rhythm. Indeed, while exerting positive tropic effects in response to physiologic and pathologic stressors, β-adrenergic stimulation influences cardiac electrophysiology and can lead to disturbances of the heart rhythm and potentially lethal arrhythmias, particularly in pathological settings. For this reason, β-blockers are widely utilized clinically as antiarrhythmics. In this review, the molecular mechanisms of β-adrenergic action in the heart, the cellular and tissue level cardiac responses to β-adrenergic stimulation, and the clinical use of β-blockers as antiarrhythmic agents are reviewed. We emphasize the complex interaction between cardiomyocyte signaling, contraction, and electrophysiology occurring over multiple time- and spatial-scales during pathophysiological responses to β-adrenergic stimulation. An integrated understanding of this complex system is essential for optimizing therapies aimed at preventing arrhythmias.
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Affiliation(s)
- Eleonora Grandi
- Department of Pharmacology, University of California Davis, United States.
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25
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Iqbal SM, Lemmens‐Gruber R. Phosphorylation of cardiac voltage-gated sodium channel: Potential players with multiple dimensions. Acta Physiol (Oxf) 2019; 225:e13210. [PMID: 30362642 PMCID: PMC6590314 DOI: 10.1111/apha.13210] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 10/14/2018] [Accepted: 10/14/2018] [Indexed: 12/11/2022]
Abstract
Cardiomyocytes are highly coordinated cells with multiple proteins organized in micro domains. Minor changes or interference in subcellular proteins can cause major disturbances in physiology. The cardiac sodium channel (NaV1.5) is an important determinant of correct electrical activity in cardiomyocytes which are localized at intercalated discs, T‐tubules and lateral membranes in the form of a macromolecular complex with multiple interacting protein partners. The channel is tightly regulated by post‐translational modifications for smooth conduction and propagation of action potentials. Among regulatory mechanisms, phosphorylation is an enzymatic and reversible process which modulates NaV1.5 channel function by attaching phosphate groups to serine, threonine or tyrosine residues. Phosphorylation of NaV1.5 is implicated in both normal physiological and pathological processes and is carried out by multiple kinases. In this review, we discuss and summarize recent literature about the (a) structure of NaV1.5 channel, (b) formation and subcellular localization of NaV1.5 channel macromolecular complex, (c) post‐translational phosphorylation and regulation of NaV1.5 channel, and (d) how these phosphorylation events of NaV1.5 channel alter the biophysical properties and affect the channel during disease status. We expect, by reviewing these aspects will greatly improve our understanding of NaV1.5 channel biology, physiology and pathology, which will also provide an insight into the mechanism of arrythmogenesis at molecular level.
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Affiliation(s)
- Shahid M. Iqbal
- Department of Pharmacology and Toxicology University of Vienna Vienna Austria
- Drugs Regulatory Authority of Pakistan Telecom Foundation (TF) Complex Islamabad Pakistan
| | - Rosa Lemmens‐Gruber
- Department of Pharmacology and Toxicology University of Vienna Vienna Austria
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26
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Marionneau C, Abriel H. Cardiac Sodium Current Under Sympathetic Control Protein Phosphatase 2A Regulates Cardiac Na+ Channels. Circ Res 2019; 124:674-676. [PMID: 30817259 DOI: 10.1161/circresaha.119.314680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - Hugues Abriel
- Ion Channels and Channelopathies Laboratory, Institute for Biochemistry and Molecular Medicine, University of Bern, Switzerland (H.A.)
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27
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Hegyi B, Bányász T, Izu LT, Belardinelli L, Bers DM, Chen-Izu Y. β-adrenergic regulation of late Na + current during cardiac action potential is mediated by both PKA and CaMKII. J Mol Cell Cardiol 2018; 123:168-179. [PMID: 30240676 DOI: 10.1016/j.yjmcc.2018.09.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/28/2018] [Accepted: 09/16/2018] [Indexed: 12/12/2022]
Abstract
Late Na+ current (INaL) significantly contributes to shaping cardiac action potentials (APs) and increased INaL is associated with cardiac arrhythmias. β-adrenergic receptor (βAR) stimulation and its downstream signaling via protein kinase A (PKA) and Ca2+/calmodulin-dependent protein kinase II (CaMKII) pathways are known to regulate INaL. However, it remains unclear how each of these pathways regulates INaL during the AP under physiological conditions. Here we performed AP-clamp experiments in rabbit ventricular myocytes to delineate the impact of each signaling pathway on INaL at different AP phases to understand the arrhythmogenic potential. During the physiological AP (2 Hz, 37 °C) we found that INaL had a basal level current independent of PKA, but partially dependent on CaMKII. βAR activation (10 nM isoproterenol, ISO) further enhanced INaL via both PKA and CaMKII pathways. However, PKA predominantly increased INaL early during the AP plateau, whereas CaMKII mainly increased INaL later in the plateau and during rapid repolarization. We also tested the role of key signaling pathways through exchange protein activated by cAMP (Epac), nitric oxide synthase (NOS) and reactive oxygen species (ROS). Direct Epac stimulation enhanced INaL similar to the βAR-induced CaMKII effect, while NOS inhibition prevented the βAR-induced CaMKII-dependent INaL enhancement. ROS generated by NADPH oxidase 2 (NOX2) also contributed to the ISO-induced INaL activation early in the AP. Taken together, our data reveal differential modulations of INaL by PKA and CaMKII signaling pathways at different AP phases. This nuanced and comprehensive view on the changes in INaL during AP deepens our understanding of the important role of INaL in reshaping the cardiac AP and arrhythmogenic potential under elevated sympathetic stimulation, which is relevant for designing therapeutic treatment of arrhythmias under pathological conditions.
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Affiliation(s)
- Bence Hegyi
- Department of Pharmacology, University of California, Davis, CA, USA.
| | - Tamás Bányász
- Department of Pharmacology, University of California, Davis, CA, USA; Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Leighton T Izu
- Department of Pharmacology, University of California, Davis, CA, USA
| | | | - Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Ye Chen-Izu
- Department of Pharmacology, University of California, Davis, CA, USA; Department of Biomedical Engineering, University of California, Davis, CA, USA; Department of Internal Medicine/Cardiology, University of California, Davis, CA, USA.
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Predicting changes to I Na from missense mutations in human SCN5A. Sci Rep 2018; 8:12797. [PMID: 30143662 PMCID: PMC6109095 DOI: 10.1038/s41598-018-30577-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 07/23/2018] [Indexed: 11/08/2022] Open
Abstract
Mutations in SCN5A can alter the cardiac sodium current INa and increase the risk of potentially lethal conditions such as Brugada and long-QT syndromes. The relation between mutations and their clinical phenotypes is complex, and systems to predict clinical severity of unclassified SCN5A variants perform poorly. We investigated if instead we could predict changes to INa, leaving the link from INa to clinical phenotype for mechanistic simulation studies. An exhaustive list of nonsynonymous missense mutations and resulting changes to INa was compiled. We then applied machine-learning methods to this dataset, and found that changes to INa could be predicted with higher sensitivity and specificity than most existing predictors of clinical significance. The substituted residues’ location on the protein correlated with channel function and strongly contributed to predictions, while conservedness and physico-chemical properties did not. However, predictions were not sufficiently accurate to form a basis for mechanistic studies. These results show that changes to INa, the mechanism through which SCN5A mutations create cardiac risk, are already difficult to predict using purely in-silico methods. This partly explains the limited success of systems to predict clinical significance of SCN5A variants, and underscores the need for functional studies of INa in risk assessment.
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Morotti S, Grandi E. Quantitative systems models illuminate arrhythmia mechanisms in heart failure: Role of the Na + -Ca 2+ -Ca 2+ /calmodulin-dependent protein kinase II-reactive oxygen species feedback. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2018; 11:e1434. [PMID: 30015404 DOI: 10.1002/wsbm.1434] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/29/2018] [Accepted: 06/16/2018] [Indexed: 12/22/2022]
Abstract
Quantitative systems modeling aims to integrate knowledge in different research areas with models describing biological mechanisms and dynamics to gain a better understanding of complex clinical syndromes. Heart failure (HF) is a chronic complex cardiac disease that results from structural or functional disorders impairing the ability of the ventricle to fill with or eject blood. Highly interactive and dynamic changes in mechanical, structural, neurohumoral, metabolic, and electrophysiological properties collectively predispose the failing heart to cardiac arrhythmias, which are responsible for about a half of HF deaths. Multiscale cardiac modeling and simulation integrate structural and functional data from HF experimental models and patients to improve our mechanistic understanding of this complex arrhythmia syndrome. In particular, they allow investigating how disease-induced remodeling alters the coupling of electrophysiology, Ca2+ and Na+ handling, contraction, and energetics that lead to rhythm derangements. The Ca2+ /calmodulin-dependent protein kinase II, which expression and activity are enhanced in HF, emerges as a critical hub that modulates the feedbacks between these various subsystems and promotes arrhythmogenesis. This article is categorized under: Physiology > Mammalian Physiology in Health and Disease Models of Systems Properties and Processes > Mechanistic Models Models of Systems Properties and Processes > Cellular Models Models of Systems Properties and Processes > Organ, Tissue, and Physiological Models.
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Affiliation(s)
- Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, California
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, California
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Yu P, Hu L, Xie J, Chen S, Huang L, Xu Z, Liu X, Zhou Q, Yuan P, Yan X, Jin J, Shen Y, Zhu W, Fu L, Chen Q, Yu J, Hu J, Cao Q, Wan R, Hong K. O-GlcNAcylation of cardiac Nav1.5 contributes to the development of arrhythmias in diabetic hearts. Int J Cardiol 2018; 260:74-81. [PMID: 29530619 DOI: 10.1016/j.ijcard.2018.02.099] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 02/20/2018] [Accepted: 02/23/2018] [Indexed: 12/22/2022]
Abstract
BACKGROUND Cardiovascular complications are major causes of mortality and morbidity in diabetic patients. The mechanisms underlying the progression of diabetic heart (DH) to ventricular arrhythmias are unclear. O-linked GlcNAcylation (O-GlcNAc) is a reversible post-translational modification for the regulation of diverse cellular processes. The purpose of this study was to assess whether the cardiac voltage-gated sodium channel (Nav1.5) is subjected to O-linked GlcNAcylation (O-GlcNAc), which plays an essential role in DH-induced arrhythmias. METHODS AND RESULTS In this study, Sprague-Dawley rats (male, 200-230 g) were treated with a single high-dose of streptozotocin (STZ, 80 mg/kg) to generate a rat model of diabetes. STZ-induced 3-month diabetic rats displayed increased susceptibility to ventricular arrhythmias. The elevated O-GlcNAc modification was correlated with decreases in both total and cytoplasmic Nav1.5 expression in vivo and in vitro. In addition, both co-immunoprecipitation and immunostaining assays demonstrated that hyperglycemia could increase the O-GlcNAc-modified Nav1.5 levels and decrease the interaction between Nav1.5 and Nav1.5-binding proteins Nedd4-2/SAP-97. Furthermore, patch-clamp measurements in HEK-293 T cells showed that Nav1.5 current densities decreased by 30% after high-glucose treatment, and the sodium currents increased via O-GlcNAc inhibition. CONCLUSION Our data suggested that hyperglycemia increased the O-GlcNAc modification of Nav1.5 expression and decreased the interaction between Nav1.5 and Nedd4-2/SAP-97, which led to the abnormal expression and distribution of Nav1.5, loss of function of the sodium channel, and prolongation of the PR/QT interval. Excessive O-GlcNAc modification of Nav1.5 is a novel signaling event, which may be an underlying contributing factor for the development of the arrhythmogenesis in DH.
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Affiliation(s)
- Peng Yu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Lili Hu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Department of Nephrology, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - Jinyan Xie
- Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Sisi Chen
- Department of General Surgery, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, China
| | - Lin Huang
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Zixuan Xu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Xiao Liu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Qiongqiong Zhou
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Ping Yuan
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Xia Yan
- Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Jiejin Jin
- Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Yang Shen
- Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Wengen Zhu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Linghua Fu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Qi Chen
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China
| | - Jianhua Yu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China
| | - Jianxin Hu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China
| | - Qing Cao
- Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China
| | - Rong Wan
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China.
| | - Kui Hong
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, 330006, China; Jiangxi Key Laboratory of Molecular Medicine, Nanchang, Jiangxi 330006, China.
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Darling AL, Uversky VN. Intrinsic Disorder and Posttranslational Modifications: The Darker Side of the Biological Dark Matter. Front Genet 2018; 9:158. [PMID: 29780404 PMCID: PMC5945825 DOI: 10.3389/fgene.2018.00158] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 04/17/2018] [Indexed: 01/05/2023] Open
Abstract
Intrinsically disordered proteins (IDPs) and intrinsically disordered protein regions (IDPRs) are functional proteins and domains that devoid stable secondary and/or tertiary structure. IDPs/IDPRs are abundantly present in various proteomes, where they are involved in regulation, signaling, and control, thereby serving as crucial regulators of various cellular processes. Various mechanisms are utilized to tightly regulate and modulate biological functions, structural properties, cellular levels, and localization of these important controllers. Among these regulatory mechanisms are precisely controlled degradation and different posttranslational modifications (PTMs). Many normal cellular processes are associated with the presence of the right amounts of precisely activated IDPs at right places and in right time. However, wrecked regulation of IDPs/IDPRs might be associated with various human maladies, ranging from cancer and neurodegeneration to cardiovascular disease and diabetes. Pathogenic transformations of IDPs/IDPRs are often triggered by altered PTMs. This review considers some of the aspects of IDPs/IDPRs and their normal and aberrant regulation by PTMs.
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Affiliation(s)
- April L Darling
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Vladimir N Uversky
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, United States.,Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Russia
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Zhong P, Quan D, Huang Y, Huang H. CaMKII Activation Promotes Cardiac Electrical Remodeling and Increases the Susceptibility to Arrhythmia Induction in High-fat Diet-Fed Mice With Hyperlipidemia Conditions. J Cardiovasc Pharmacol 2017; 70:245-254. [PMID: 28662005 PMCID: PMC5642343 DOI: 10.1097/fjc.0000000000000512] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 06/08/2017] [Indexed: 01/09/2023]
Abstract
BACKGROUND Obesity/hyperlipidemia is closely related to both atrial and ventricular arrhythmias. CaMKII, a multifunctional serine/threonine kinase, has been involved in cardiac arrhythmias of different etiologies. However, its role in obesity/hyperlipidemia-related cardiac arrhythmia is unexplored. The aim of this was to determine the involvement of CaMKII in the process. METHODS Adult male APOE mice were fed a high-fat diet (HFD), administrated with KN93 (10 mg·kg·2d), a specific inhibitor of CaMKII. Serum lipid and glucose profile, cardiac function, and surface electrocardiogram were determined. Electrophysiological study and epicardial activation mapping were performed in Langendorff-perfused heart. Expression of cardiac ion channels, gap junction proteins, Ca handling proteins, and CaMKII were evaluated, coupled with histological analysis. RESULTS A hyperlipidemia condition was induced by HFD in the APOE mice, which was associated with increased expression and activity of CaMKII in the hearts. In Langendorff-perfused hearts, HFD-induced heart showed increased arrhythmia inducibility, prolonged action potential duration, and decreased action potential duration alternans thresholds, coupled with slow ventricular conduction, connexin-43 upregulation, and interstitial fibrosis. Downregulation of ion channels including Cav1.2 and Kv4.2/Kv4.3 and disturbed Ca handling proteins were also observed in HFD-induced heart. Interestingly, all these alterations were significantly inhibited by KN93 treatment. CONCLUSION Our results demonstrated an adverse effect of metabolic components on cardiac electrophysiology and implicated an important role of CaMKII underlying this process.
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Affiliation(s)
- Peng Zhong
- Department of Cardiology, Renming Hospital of Wuhan University, Wuhan, PR China
- Cardiovascular Research Institute, Wuhan University, Wuhan, PR China; and
- Huei Key Laboratory of Cardiology, Wuhan, PR China
| | - Dajun Quan
- Department of Cardiology, Renming Hospital of Wuhan University, Wuhan, PR China
- Cardiovascular Research Institute, Wuhan University, Wuhan, PR China; and
- Huei Key Laboratory of Cardiology, Wuhan, PR China
| | - Yan Huang
- Department of Cardiology, Renming Hospital of Wuhan University, Wuhan, PR China
- Cardiovascular Research Institute, Wuhan University, Wuhan, PR China; and
- Huei Key Laboratory of Cardiology, Wuhan, PR China
| | - He Huang
- Department of Cardiology, Renming Hospital of Wuhan University, Wuhan, PR China
- Cardiovascular Research Institute, Wuhan University, Wuhan, PR China; and
- Huei Key Laboratory of Cardiology, Wuhan, PR China
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Abdelsayed M, Baruteau A, Gibbs K, Sanatani S, Krahn AD, Probst V, Ruben PC. Differential calcium sensitivity in Na V 1.5 mixed syndrome mutants. J Physiol 2017; 595:6165-6186. [PMID: 28734073 PMCID: PMC5599485 DOI: 10.1113/jp274536] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/21/2017] [Indexed: 01/13/2023] Open
Abstract
KEY POINTS SCN5a mutations may express gain-of-function (Long QT Syndrome-3), loss-of-function (Brugada Syndrome 1) or both (mixed syndromes), depending on the mutation and environmental triggers. One such trigger may be an increase in cytosolic calcium, accompanying exercise. Many mixed syndromes mutants, including ∆KPQ, E1784K, 1795insD and Q1909R, are found in calcium-sensitive regions. Elevated cytosolic calcium attenuates gain-of-function properties in ∆KPQ, 1795insD and Q1909R, but not in E1784K. By contrast, elevated cytosolic calcium further exacerbates gain-of-function in E1784K by destabilizing slow inactivation. Action potential modelling, using a modified O'Hara Rudy model, suggests that elevated heart rate rescues action potential duration in ∆KPQ, 1795insD and Q1909R, but not in E1784K. Action potential simulations suggest that E1784K carriers have an increased intracellular sodium-to-calcium ratio under bradycardia and tachycardia conditions. Elevated cytosolic calcium, which is common during high heart rates, ameliorates or exacerbates the mixed syndrome phenotype depending on the genetic signature. ABSTRACT Inherited arrhythmias may arise from mutations in the gene for SCN5a, which encodes the cardiac voltage-gated sodium channel, NaV 1.5. Mutants in NaV 1.5 result in Brugada Syndrome (BrS1), Long-QT Syndrome (LQT3) or mixed syndromes (an overlap of BrS1/LQT3). Exercise is a potential arrhythmogenic trigger in mixed syndromes. We aimed to determine the effects of elevated cytosolic calcium, which is common during exercise, in mixed syndrome NaV 1.5 mutants. We used whole-cell patch clamp to assess the biophysical properties of NaV 1.5 wild-type (WT), ∆KPQ, E1784K, 1795insD and Q1909R mutants in human embryonic kidney 293 cells transiently transfected with the NaV 1.5 α subunit (WT or mutants), β1 subunit and enhanced green fluorescent protein. Voltage-dependence and kinetics were measured at cytosolic calcium levels of approximately 0, 500 and 2500 nm. In silico, action potential (AP) model simulations were performed using a modified O'Hara Rudy model. Elevated cytosolic calcium attenuates the late sodium current in ∆KPQ, 1795insD and Q1909R, but not in E1784K. Elevated cytosolic calcium restores steady-state slow inactivation (SSSI) to the WT-form in Q1909R, but depolarized SSSI in E1784K. Our AP simulations showed a frequency-dependent reduction of AP duration in ∆KPQ, 1795insD and Q1909R carriers. In E1784K, AP duration is relatively prolonged at both low and high heart rates, resulting in a sodium overload. Cellular perturbations during exercise may affect BrS1/LQT3 patients differently depending on their individual genetic signature. Thus, exercise may be therapeutic or may be an arrhythmogenic trigger in some SCN5a patients.
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Affiliation(s)
- Mena Abdelsayed
- Department of Biomedical Physiology and KinesiologySimon Fraser UniversityBurnabyCanada
| | - Alban‐Elouen Baruteau
- LIRYC Institute, Division of Pediatric Cardiology, Haut‐Lévèque HospitalBordeaux UniversityBordeauxFrance
| | - Karen Gibbs
- Division of CardiologyUniversity of British ColumbiaVancouverCanada
| | - Shubhayan Sanatani
- Department of Pediatrics, University of British ColumbiaBC Children's HospitalVancouverCanada
| | - Andrew D. Krahn
- Division of CardiologyUniversity of British ColumbiaVancouverCanada
| | - Vincent Probst
- L'institut du thorax, Inserm 1087Université de NantesNantesFrance
| | - Peter C. Ruben
- Department of Biomedical Physiology and KinesiologySimon Fraser UniversityBurnabyCanada
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Campos FO, Shiferaw Y, Vigmond EJ, Plank G. Stochastic spontaneous calcium release events and sodium channelopathies promote ventricular arrhythmias. CHAOS (WOODBURY, N.Y.) 2017; 27:093910. [PMID: 28964108 PMCID: PMC5568869 DOI: 10.1063/1.4999612] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Premature ventricular complexes (PVCs), the first initiating beats of a variety of cardiac arrhythmias, have been associated with spontaneous calcium release (SCR) events at the cell level. However, the mechanisms underlying the degeneration of such PVCs into arrhythmias are not fully understood. The objective of this study was to investigate the conditions under which SCR-mediated PVCs can lead to ventricular arrhythmias. In particular, we sought to determine whether sodium (Na+) current loss-of-function in the structurally normal ventricles provides a substrate for unidirectional conduction block and reentry initiated by SCR-mediated PVCs. To achieve this goal, a stochastic model of SCR was incorporated into an anatomically accurate compute model of the rabbit ventricles with the His-Purkinje system (HPS). Simulations with reduced Na+ current due to a negative-shift in the steady-state channel inactivation showed that SCR-mediated delayed afterdepolarizations led to PVC formation in the HPS, where the electrotonic load was lower, conduction block, and reentry in the 3D myocardium. Moreover, arrhythmia initiation was only possible when intrinsic electrophysiological heterogeneity in action potential within the ventricles was present. In conclusion, while benign in healthy individuals SCR-mediated PVCs can lead to life-threatening ventricular arrhythmias when combined with Na+ channelopathies.
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Affiliation(s)
- Fernando O Campos
- Department of Congenital Heart Diseases and Pediatric Cardiology, German Heart Institute Berlin, Berlin, Germany
| | - Yohannes Shiferaw
- Department of Physics, California State University, Northridge, California 91330, USA
| | | | - Gernot Plank
- Institute of Biophysics, Medical University of Graz, Graz, Austria
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Luo L, Ning F, Du Y, Song B, Yang D, Salvage SC, Wang Y, Fraser JA, Zhang S, Ma A, Wang T. Calcium-dependent Nedd4-2 upregulation mediates degradation of the cardiac sodium channel Nav1.5: implications for heart failure. Acta Physiol (Oxf) 2017; 221:44-58. [PMID: 28296171 DOI: 10.1111/apha.12872] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/08/2016] [Accepted: 03/03/2017] [Indexed: 12/18/2022]
Abstract
AIM Reductions in voltage-gated sodium channel (Nav1.5) function/expression provide a slowed-conduction substrate for cardiac arrhythmias. Nedd4-2, which is activated by calcium, post-translationally modulates Nav1.5. We aim to investigate whether elevated intracellular calcium ([Ca2+ ]i ) reduces Nav1.5 through Nedd4-2 and its role in heart failure (HF). METHODS Using a combination of biochemical, electrophysiological, cellular and in vivo methods, we tested the effect and mechanism of calcium on Nedd4-2 and in turn Nav1.5. RESULTS Increased [Ca2+ ]i , following 24-h ionomycin treatment, decreased sodium current (INa ) density and Nav1.5 protein without altering its mRNA in both neonatal rat cardiomyocytes (NRCMs) and HEK 293 cells stably expressing Nav1.5. The calcium chelator BAPTA-AM restored the reduced Nav1.5 and INa in NRCMs pre-treated by ionomycin. Nav1.5 was decreased by Nedd4-2 transfection and further decreased by 6-h ionomycin treatment. These effects were not observed in cells transfected with the catalytically inactive mutant, Nedd4-2 C801S, or with Y1977A-Nav1.5 mutant containing the impaired Nedd4-2 binding motif. Furthermore, elevated [Ca2+ ]i increased Nedd4-2, the interaction between Nedd4-2 and Nav1.5, and Nav1.5 ubiquitination. Nav1.5 protein is decreased, whereas Nedd4-2 is increased in volume-overload HF rat hearts, with increased co-localization of Nav1.5 with ubiquitin or Nedd4-2 as indicated by immunofluorescence staining. BAPTA-AM rescued the reduced Nav1.5 protein, INa and increased Nedd4-2 in hypertrophied NRCMs induced by isoproterenol or angiotensin II. CONCLUSION Calcium-mediated increases in Nedd4-2 downregulate Nav1.5 by ubiquitination. Nav1.5 is downregulated and co-localizes with Nedd4-2 and ubiquitin in failing rat heart. These data suggest a role of Nedd4-2 in Nav1.5 downregulation in HF.
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Affiliation(s)
- L. Luo
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Xi'an China
| | - F. Ning
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Xi'an China
| | - Y. Du
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Xi'an China
| | - B. Song
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Xi'an China
| | - D. Yang
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Xi'an China
| | - S. C. Salvage
- Physiological Laboratory; University of Cambridge; Cambridge UK
| | - Y. Wang
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Xi'an China
| | - J. A. Fraser
- Physiological Laboratory; University of Cambridge; Cambridge UK
| | - S. Zhang
- Department of Biomedical and Molecular Sciences; Queen's University; Kingston Ontario Canada
| | - A. Ma
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Xi'an China
- Key Laboratory of Molecular Cardiology; Xi'an Shaanxi Province China
- Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University); Ministry of Education; Xi'an China
| | - T. Wang
- Department of Cardiovascular Medicine; First Affiliated Hospital of Xi'an Jiaotong University; Xi'an China
- Key Laboratory of Molecular Cardiology; Xi'an Shaanxi Province China
- Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University); Ministry of Education; Xi'an China
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Bubb KJ, Birgisdottir AB, Tang O, Hansen T, Figtree GA. Redox modification of caveolar proteins in the cardiovascular system- role in cellular signalling and disease. Free Radic Biol Med 2017; 109:61-74. [PMID: 28188926 DOI: 10.1016/j.freeradbiomed.2017.02.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 01/18/2017] [Accepted: 02/05/2017] [Indexed: 02/07/2023]
Abstract
Rapid and coordinated release of a variety of reactive oxygen species (ROS) such as superoxide (O2.-), hydrogen peroxide (H2O2) and peroxynitrite, in specific microdomains, play a crucial role in cell signalling in the cardiovascular system. These reactions are mediated by reversible and functional modifications of a wide variety of key proteins. Dysregulation of this oxidative signalling occurs in almost all forms of cardiovascular disease (CVD), including at the very early phases. Despite the heavily publicized failure of "antioxidants" to improve CVD progression, pharmacotherapies such as those targeting the renin-angiotensin system, or statins, exert at least part of their large clinical benefit via modulating cellular redox signalling. Over 250 proteins, including receptors, ion channels and pumps, and signalling proteins are found in the caveolae. An increasing proportion of these are being recognized as redox regulated-proteins, that reside in the immediate vicinity of the two major cellular sources of ROS, nicotinamide adenine dinucleotide phosphate oxidase (Nox) and uncoupled endothelial nitric oxide synthase (eNOS). This review focuses on what is known about redox signalling within the caveolae, as well as endogenous protective mechanisms utilized by the cell, and new approaches to targeting dysregulated redox signalling in the caveolae as a therapeutic strategy in CVD.
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Affiliation(s)
- Kristen J Bubb
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Asa Birna Birgisdottir
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia; Department of Cardiothoracic and Vascular Surgery, Heart and Lung Clinic, University Hospital of North Norway, Tromsø, Norway
| | - Owen Tang
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Thomas Hansen
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Gemma A Figtree
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia.
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β1-Adrenergic receptor Arg389Gly polymorphism affects the antiarrhythmic efficacy of flecainide in patients with coadministration of β-blockers. Pharmacogenet Genomics 2017; 26:481-5. [PMID: 27500822 DOI: 10.1097/fpc.0000000000000239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE β1-Adrenergic receptor (β1-AR) stimulation modulates the antiarrhythmic activities of sodium channel blockers. The β1-AR Gly389 variant shows a marked decrease in agonist-stimulated cyclic AMP production compared with that of the wild-type Arg389 in vitro. We investigated whether the Arg389Gly polymorphism affects the efficacy of flecainide, a typical sodium channel blocker, in patients with or without coadministration of β-blockers. METHODS The effects of the β1-AR Arg389Gly polymorphism on the antiarrhythmic efficacy of flecainide were compared between with and without coadministered β-blockers in 159 patients with supraventricular tachyarrhythmia. The antiarrhythmic efficacy of flecainide was assessed for at least 2 months by evaluating symptomatology, 12-lead ECGs, and Holter monitoring results. RESULTS Genetic differences in the antiarrhythmic efficacy of flecainide were observed in patients with coadministration of β-blockers. Tachyarrhythmia was well controlled in 60% of Arg389-homozygotes, 30% of Gly389-heterozygotes, and 0% of Gly389-homozygotes (P=0.001). In contrast, no difference in the antiarrhythmic efficacy was observed among the three genotypes in the patients without coadministration of β-blockers (64, 70, and 60%, respectively). Heart rate in tachyarrhythmia in patients treated with flecainide was significantly higher in Gly389 carriers than in Arg389-homozygotes (P=0.013). CONCLUSION The Gly389 polymorphism decreased the antiarrhythmic efficacy of flecainide when coadministered with β-blockers. The results indicate that the Arg389Gly polymorphism may play an important role in predicting the efficacy of flecainide in patients with coadministration of β-blockers.
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Vikram A, Lewarchik CM, Yoon JY, Naqvi A, Kumar S, Morgan GM, Jacobs JS, Li Q, Kim YR, Kassan M, Liu J, Gabani M, Kumar A, Mehdi H, Zhu X, Guan X, Kutschke W, Zhang X, Boudreau RL, Dai S, Matasic DS, Jung SB, Margulies KB, Kumar V, Bachschmid MM, London B, Irani K. Sirtuin 1 regulates cardiac electrical activity by deacetylating the cardiac sodium channel. Nat Med 2017; 23:361-367. [PMID: 28191886 PMCID: PMC6218171 DOI: 10.1038/nm.4284] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 01/17/2017] [Indexed: 11/08/2022]
Abstract
The voltage-gated cardiac Na+ channel (Nav1.5), encoded by the SCN5A gene, conducts the inward depolarizing cardiac Na+ current (INa) and is vital for normal cardiac electrical activity. Inherited loss-of-function mutations in SCN5A lead to defects in the generation and conduction of the cardiac electrical impulse and are associated with various arrhythmia phenotypes. Here we show that sirtuin 1 deacetylase (Sirt1) deacetylates Nav1.5 at lysine 1479 (K1479) and stimulates INa via lysine-deacetylation-mediated trafficking of Nav1.5 to the plasma membrane. Cardiac Sirt1 deficiency in mice induces hyperacetylation of K1479 in Nav1.5, decreases expression of Nav1.5 on the cardiomyocyte membrane, reduces INa and leads to cardiac conduction abnormalities and premature death owing to arrhythmia. The arrhythmic phenotype of cardiac-Sirt1-deficient mice recapitulated human cardiac arrhythmias resulting from loss of function of Nav1.5. Increased Sirt1 activity or expression results in decreased lysine acetylation of Nav1.5, which promotes the trafficking of Nav1.5 to the plasma membrane and stimulation of INa. As compared to wild-type Nav1.5, Nav1.5 with K1479 mutated to a nonacetylatable residue increases peak INa and is not regulated by Sirt1, whereas Nav1.5 with K1479 mutated to mimic acetylation decreases INa. Nav1.5 is hyperacetylated on K1479 in the hearts of patients with cardiomyopathy and clinical conduction disease. Thus, Sirt1, by deacetylating Nav1.5, plays an essential part in the regulation of INa and cardiac electrical activity.
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Affiliation(s)
- Ajit Vikram
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | | | - Jin-Young Yoon
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Asma Naqvi
- University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Santosh Kumar
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Gina M Morgan
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Julia S Jacobs
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Qiuxia Li
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Young-Rae Kim
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Modar Kassan
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Jing Liu
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Mohanad Gabani
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Ajay Kumar
- University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Haider Mehdi
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Xiaodong Zhu
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Xiaoqun Guan
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - William Kutschke
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Xiaoming Zhang
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Ryan L Boudreau
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Shengchuan Dai
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Daniel S Matasic
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Saet-Byel Jung
- Research Center for Endocrine and Metabolic Diseases, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Kenneth B Margulies
- Cardiovascular Division, Department of Medicine, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Vikas Kumar
- Vascular Biology Section, Cardiovascular Proteomics Center, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Markus M Bachschmid
- Vascular Biology Section, Cardiovascular Proteomics Center, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Barry London
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Kaikobad Irani
- Division of Cardiovascular Medicine, Department of Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
- Fraternal Order of Eagles Diabetes Research Center, Pappajohn Biomedical Institute, and Heart and Vascular Center, University of Iowa, University of Iowa, Iowa City, Iowa, USA
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Yang Z, Lu D, Zhang L, Hu J, Nie Z, Xie C, Qiu F, Cheng H, Yan Y. p.N1380del mutation in the pore-forming region of SCN5A gene is associated with cardiac conduction disturbance and ventricular tachycardia. Acta Biochim Biophys Sin (Shanghai) 2017; 49:270-276. [PMID: 28159958 DOI: 10.1093/abbs/gmx003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Indexed: 12/11/2022] Open
Abstract
Cardiac sodium channel plays a key role in the fast depolarization and maintenance of impulse conduction in cardiomyocytes. Mutations of SCN5A gene can lead to many types of arrhythmias. A 14-year-old boy with familial paternal history of sudden unexpected nocturnal death was admitted to hospital with recurrent syncope. A cardiac channelopathy was suspected and a pathogenic ion channel was searched for mutation identification. The proband manifested sinus node dysfunction, ventricular tachycardia, cardiac conduction disturbance involving atrioventricular node and His bundle. The proband and his mother received whole exome sequencing. A heterozygous in-frame deletion N1380del on exon 23 of SCN5A gene locating in a highly conserved pore residue in domain III (S5-S6) was revealed in the proband. The mutation was assessed in other family members by Sanger sequencing. The proband's living uncle and two sisters were asymptomatic mutation carriers with different degrees of cardiac conduction disturbance. Functional analysis was conducted using whole-cell patch clamping in HEK293T cells transfected with wild-type or mutant channels. The HEK293T cells transfected with plasmid pcDNA3.1-N1380del-SCN5A had no detectable sodium current. Overall, N1380del mutation of SCN5A gene leads to loss of function of sodium channel. N1380del is a pathogenetic mutation which can cause cardiac conduction defect and ventricular tachycardia.
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Affiliation(s)
- Zhen Yang
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Danbo Lu
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Lei Zhang
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Jialu Hu
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Zhenning Nie
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Chang Xie
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai 200031, China
| | - Fang Qiu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai 200031, China
| | - Hua Cheng
- WuXi NextCODE Genomics, Shanghai 200131, China
| | - Yan Yan
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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Edwards AG, Louch WE. Species-Dependent Mechanisms of Cardiac Arrhythmia: A Cellular Focus. CLINICAL MEDICINE INSIGHTS-CARDIOLOGY 2017; 11:1179546816686061. [PMID: 28469490 PMCID: PMC5392019 DOI: 10.1177/1179546816686061] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/20/2016] [Indexed: 12/17/2022]
Abstract
Although ventricular arrhythmia remains a leading cause of morbidity and mortality, available antiarrhythmic drugs have limited efficacy. Disappointing progress in the development of novel, clinically relevant antiarrhythmic agents may partly be attributed to discrepancies between humans and animal models used in preclinical testing. However, such differences are at present difficult to predict, requiring improved understanding of arrhythmia mechanisms across species. To this end, we presently review interspecies similarities and differences in fundamental cardiomyocyte electrophysiology and current understanding of the mechanisms underlying the generation of afterdepolarizations and reentry. We specifically highlight patent shortcomings in small rodents to reproduce cellular and tissue-level arrhythmia substrate believed to be critical in human ventricle. Despite greater ease of translation from larger animal models, discrepancies remain and interpretation can be complicated by incomplete knowledge of human ventricular physiology due to low availability of explanted tissue. We therefore point to the benefits of mathematical modeling as a translational bridge to understanding and treating human arrhythmia.
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Affiliation(s)
- Andrew G Edwards
- Center for Biomedical Computing, Simula Research Laboratory, Lysaker, Norway.,Center for Cardiological Innovation, Simula Research Laboratory, Lysaker, Norway.,Department of Biosciences, University of Oslo, Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, University of Oslo, Oslo, Norway
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DeMarco KR, Clancy CE. Cardiac Na Channels: Structure to Function. CURRENT TOPICS IN MEMBRANES 2016; 78:287-311. [PMID: 27586288 DOI: 10.1016/bs.ctm.2016.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Heart rhythms arise from electrical activity generated by precisely timed opening and closing of ion channels in individual cardiac myocytes. Opening of the primary cardiac voltage-gated sodium (NaV1.5) channel initiates cellular depolarization and the propagation of an electrical action potential that promotes coordinated contraction of the heart. The regularity of these contractile waves is critically important since it drives the primary function of the heart: to act as a pump that delivers blood to the brain and vital organs. When electrical activity goes awry during a cardiac arrhythmia, the pump does not function, the brain does not receive oxygenated blood, and death ensues. Perturbations to NaV1.5 may alter the structure, and hence the function, of the ion channel and are associated downstream with a wide variety of cardiac conduction pathologies, such as arrhythmias.
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Affiliation(s)
- K R DeMarco
- University of California, Davis, Davis, CA, United States
| | - C E Clancy
- University of California, Davis, Davis, CA, United States
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43
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Ortiz-Bonnin B, Rinné S, Moss R, Streit AK, Scharf M, Richter K, Stöber A, Pfeufer A, Seemann G, Kääb S, Beckmann BM, Decher N. Electrophysiological characterization of a large set of novel variants in the SCN5A-gene: identification of novel LQTS3 and BrS mutations. Pflugers Arch 2016; 468:1375-87. [PMID: 27287068 DOI: 10.1007/s00424-016-1844-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/16/2016] [Accepted: 05/29/2016] [Indexed: 01/08/2023]
Abstract
SCN5A encodes for the α-subunit of the cardiac voltage-gated sodium channel Nav1.5. Gain-of-function mutations in SCN5A are related to congenital long QT syndrome (LQTS3) characterized by delayed cardiac repolarization, leading to a prolonged QT interval in the ECG. Loss-of-function mutations in SCN5A are related to Brugada syndrome (BrS), characterized by an ST-segment elevation in the right precordial leads (V1-V3). The aim of this study was the characterization of a large set of novel SCN5A variants found in patients with different cardiac phenotypes, mainly LQTS and BrS. SCN5A variants of 13 families were functionally characterized in Xenopus laevis oocytes using the two-electrode voltage-clamp technique. We found in most of the cases, but not all, that the electrophysiology of the variants correlated with the clinically diagnosed phenotype. A susceptibility to develop LQTS can be suggested in patients carrying the variants S216L, K480N, A572D, F816Y, and G983D. However, taking the phenotype into account, the presence of the variants in genomic data bases, the mutational segregation, combined with our in vitro and in silico experiments, the variants S216L, S262G, K480N, A572D, F816Y, G983D, and T1526P remain as variants of unknown significance. However, the SCN5A variants R568H and A993T can be classified as pathogenic LQTS3 causing mutations, while R222stop and R2012H are novel BrS causing mutations.
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Affiliation(s)
- Beatriz Ortiz-Bonnin
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 1-2, 35037, Marburg, Germany
| | - Susanne Rinné
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 1-2, 35037, Marburg, Germany
| | - Robin Moss
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg - Bad Krozingen, Medical Center, University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anne K Streit
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 1-2, 35037, Marburg, Germany
| | - Michael Scharf
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 1-2, 35037, Marburg, Germany
| | - Katrin Richter
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 1-2, 35037, Marburg, Germany
| | - Anika Stöber
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 1-2, 35037, Marburg, Germany
| | - Arne Pfeufer
- Helmholtz Zentrum München GmbH, Deutsches Forschungszentrum für Gesundheit und Umwelt, Institut für Humangenetik, Oberschleißheim, Germany
| | - Gunnar Seemann
- Institute for Experimental Cardiovascular Medicine, University Heart Centre Freiburg - Bad Krozingen, Medical Center, University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Stefan Kääb
- Department of Medicine, University Hospital of the Ludwig Maximilians University-Campus Innenstadt and Großhadern, Munich, Germany
| | - Britt-Maria Beckmann
- Department of Medicine, University Hospital of the Ludwig Maximilians University-Campus Innenstadt and Großhadern, Munich, Germany
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, Philipps-University of Marburg, Deutschhausstraße 1-2, 35037, Marburg, Germany.
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44
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Gawali V, Todt H. Mechanism of Inactivation in Voltage-Gated Na+ Channels. CURRENT TOPICS IN MEMBRANES 2016; 78:409-50. [DOI: 10.1016/bs.ctm.2016.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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45
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Wu H, Chen X, Cheng J, Qi Y. SUMOylation and Potassium Channels: Links to Epilepsy and Sudden Death. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 103:295-321. [PMID: 26920693 DOI: 10.1016/bs.apcsb.2015.11.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuronal potassium ion channels play an essential role in the generation of the action potential and excitability of neurons. The dysfunction of ion channel subunits can cause channelopathies, which are associated in some cases with sudden unexplained death in epilepsy SUDEP. The physiological roles of neuronal ion channels have been largely determined, but little is known about the molecular mechanisms underlying neurological channelopathies, especially the determinants of the channels' regulation. SUMO (small ubiquitin-like modifier) proteins covalently conjugate lysine residues in a large number of target proteins and modify their functions. SUMO modification (SUMOylation) has emerged as an important regulatory mechanism for protein stability, function, subcellular localization, and protein-protein interactions. Since SUMO was discovered almost 20 years ago, the biological contribution of SUMOylation has not fully understood. It is until recently that the physiological impacts of SUMOylation on the regulation of neuronal potassium ion channels have been investigated. It is well established that SUMOylation controls many aspects of nuclear function, but it is now clear that it is also a key determinant in the function of potassium channels, and SUMOylation has also been implicated in a wide range of channelopathies, including epilepsy and sudden death.
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Affiliation(s)
- Hongmei Wu
- College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, PR China
| | - Xu Chen
- College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, PR China
| | - Jinke Cheng
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, Shanghai, PR China
| | - Yitao Qi
- College of Life Sciences, Shaanxi Normal University, Xi'an, Shaanxi, PR China.
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46
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Clancy CE, Chen-Izu Y, Bers DM, Belardinelli L, Boyden PA, Csernoch L, Despa S, Fermini B, Hool LC, Izu L, Kass RS, Lederer WJ, Louch WE, Maack C, Matiazzi A, Qu Z, Rajamani S, Rippinger CM, Sejersted OM, O'Rourke B, Weiss JN, Varró A, Zaza A. Deranged sodium to sudden death. J Physiol 2015; 593:1331-45. [PMID: 25772289 DOI: 10.1113/jphysiol.2014.281204] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 10/14/2014] [Indexed: 12/19/2022] Open
Abstract
In February 2014, a group of scientists convened as part of the University of California Davis Cardiovascular Symposium to bring together experimental and mathematical modelling perspectives and discuss points of consensus and controversy on the topic of sodium in the heart. This paper summarizes the topics of presentation and discussion from the symposium, with a focus on the role of aberrant sodium channels and abnormal sodium homeostasis in cardiac arrhythmias and pharmacotherapy from the subcellular scale to the whole heart. Two following papers focus on Na(+) channel structure, function and regulation, and Na(+)/Ca(2+) exchange and Na(+)/K(+) ATPase. The UC Davis Cardiovascular Symposium is a biannual event that aims to bring together leading experts in subfields of cardiovascular biomedicine to focus on topics of importance to the field. The focus on Na(+) in the 2014 symposium stemmed from the multitude of recent studies that point to the importance of maintaining Na(+) homeostasis in the heart, as disruption of homeostatic processes are increasingly identified in cardiac disease states. Understanding how disruption in cardiac Na(+)-based processes leads to derangement in multiple cardiac components at the level of the cell and to then connect these perturbations to emergent behaviour in the heart to cause disease is a critical area of research. The ubiquity of disruption of Na(+) channels and Na(+) homeostasis in cardiac disorders of excitability and mechanics emphasizes the importance of a fundamental understanding of the associated mechanisms and disease processes to ultimately reveal new targets for human therapy.
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Affiliation(s)
- Colleen E Clancy
- Department of Pharmacology, University of California, Davis, Genome Building Rm 3503, Davis, CA, 95616-8636, USA
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Chen-Izu Y, Shaw RM, Pitt GS, Yarov-Yarovoy V, Sack JT, Abriel H, Aldrich RW, Belardinelli L, Cannell MB, Catterall WA, Chazin WJ, Chiamvimonvat N, Deschenes I, Grandi E, Hund TJ, Izu LT, Maier LS, Maltsev VA, Marionneau C, Mohler PJ, Rajamani S, Rasmusson RL, Sobie EA, Clancy CE, Bers DM. Na+ channel function, regulation, structure, trafficking and sequestration. J Physiol 2015; 593:1347-60. [PMID: 25772290 DOI: 10.1113/jphysiol.2014.281428] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 11/02/2014] [Indexed: 12/19/2022] Open
Abstract
This paper is the second of a series of three reviews published in this issue resulting from the University of California Davis Cardiovascular Symposium 2014: Systems approach to understanding cardiac excitation-contraction coupling and arrhythmias: Na(+) channel and Na(+) transport. The goal of the symposium was to bring together experts in the field to discuss points of consensus and controversy on the topic of sodium in the heart. The present review focuses on Na(+) channel function and regulation, Na(+) channel structure and function, and Na(+) channel trafficking, sequestration and complexing.
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Affiliation(s)
- Ye Chen-Izu
- Department of Pharmacology, University of California, Davis, USA; Department of Biomedical Engineering, University of California, Davis, USA; Department of Internal Medicine/Cardiology, University of California, Davis, USA
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Frolov RV, Weckström M. Harnessing the Flow of Excitation: TRP, Voltage-Gated Na(+), and Voltage-Gated Ca(2+) Channels in Contemporary Medicine. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 103:25-95. [PMID: 26920687 DOI: 10.1016/bs.apcsb.2015.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cellular signaling in both excitable and nonexcitable cells involves several classes of ion channels. Some of them are of minor importance, with very specialized roles in physiology, but here we concentrate on three major channel classes: TRP (transient receptor potential channels), voltage-gated sodium channels (Nav), and voltage-gated calcium channels (Cav). Here, we first propose a conceptual framework binding together all three classes of ion channels, a "flow-of-excitation model" that takes into account the inputs mediated by TRP and other similar channels, the outputs invariably provided by Cav channels, and the regenerative transmission of signals in the neural networks, for which Nav channels are responsible. We use this framework to examine the function, structure, and pharmacology of these channel classes both at cellular and also at whole-body physiological level. Building on that basis we go through the pathologies arising from the direct or indirect malfunction of the channels, utilizing ion channel defects, the channelopathies. The pharmacological interventions affecting these channels are numerous. Part of those are well-established treatments, like treatment of hypertension or some forms of epilepsy, but many other are deeply problematic due to poor drug specificity, ion channel diversity, and widespread expression of the channels in tissues other than those actually targeted.
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Affiliation(s)
- Roman V Frolov
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland.
| | - Matti Weckström
- Division of Biophysics, Department of Physics, University of Oulu, Oulun Yliopisto, Finland
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49
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Zhao Y, Huang H, Du Y, Li X, Lv T, Zhang S, Wei H, Shang J, Liu P, Liu H. β1-Adrenoceptor autoantibodies affect action potential duration and delayed rectifier potassium currents in guinea pigs. Cardiovasc Toxicol 2015; 15:1-9. [PMID: 24894912 DOI: 10.1007/s12012-014-9261-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
β1-Adrenoceptor autoantibodies (β1-AAs) affect the action potential duration (APD) in cardiomyocytes and are related to ventricular arrhythmias. The delayed rectifier potassium current (I K) plays a crucial role in APD, but the effects of β1-AAs on I K have not been completely illuminated. This work aimed to observe the effects of β1-AAs on I K and APD and further explore the mechanisms of β1-AA-mediated ventricular arrhythmias. β1-AAs were obtained from sera of patients with coronary heart disease (CHD) and nonsustained ventricular tachycardia. With whole-cell patch clamp technique, action potentials and I K were recorded. The results illustrated 0.1 μmol/L β1-AAs shortened APD at 50 % (APD50) and 90 % (APD90) of the repolarization. However, at 0.01 μmol/L, β1-AAs had no effects on either APD90 or APD50 (P > 0.05). At 0.001 μmol/L, β1-AAs significantly prolonged APD90 and APD50. Moreover, β1-AAs (0.001, 0.01, 0.1 μmol/L) dose-dependently increased the rapidly activating delayed rectifier potassium current (I Kr), but similarly decreased the slowly activating delayed rectifier potassium current (I Ks) and increased L-type calcium currents at the different concentrations. Taken together, the IKr increase induced by high β1-AA concentrations is responsible for a significant APD reduction which would contribute to repolarization changes and trigger the malignant ventricular arrhythmias in CHD patients.
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Affiliation(s)
- Yuhui Zhao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, 100069, China
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Liu MB, de Lange E, Garfinkel A, Weiss JN, Qu Z. Delayed afterdepolarizations generate both triggers and a vulnerable substrate promoting reentry in cardiac tissue. Heart Rhythm 2015; 12:2115-24. [PMID: 26072025 PMCID: PMC4583816 DOI: 10.1016/j.hrthm.2015.06.019] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND Delayed afterdepolarizations (DADs) have been well characterized as arrhythmia triggers, but their role in generating a tissue substrate vulnerable to reentry is not well understood. OBJECTIVE The purpose of this study was to test the hypothesis that random DADs can self-organize to generate both an arrhythmia trigger and a vulnerable substrate simultaneously in cardiac tissue as a result of gap junction coupling. METHODS Computer simulations in 1-dimensional cable and 2-dimensional tissue models were performed. The cellular DAD amplitude was varied by changing the strength of sarcoplasmic reticulum calcium release. Random DAD latency and amplitude in different cells were simulated using gaussian distributions. RESULTS Depending on the strength of spontaneous sarcoplasmic reticulum calcium release and other conditions, random DADs in cardiac tissue resulted in the following behaviors: (1) triggered activity (TA); (2) a vulnerable tissue substrate causing unidirectional conduction block and reentry by inactivating sodium channels; (3) both triggers and a vulnerable substrate simultaneously by generating TA in regions next to regions with subthreshold DADs susceptible to unidirectional conduction block and reentry. The probability of the latter 2 behaviors was enhanced by reduced sodium channel availability, reduced gap junction coupling, increased tissue heterogeneity, and less synchronous DAD latency. CONCLUSION DADs can self-organize in tissue to generate arrhythmia triggers, a vulnerable tissue substrate, and both simultaneously. Reduced sodium channel availability and gap junction coupling potentiate this mechanism of arrhythmias, which are relevant to a variety of heart disease conditions.
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Affiliation(s)
- Michael B Liu
- UCLA Cardiovascular Research Laboratory; Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California
| | - Enno de Lange
- UCLA Cardiovascular Research Laboratory; Department of Knowledge Engineering, Maastricht University, Maastricht, The Netherlands
| | - Alan Garfinkel
- UCLA Cardiovascular Research Laboratory; Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California; Department of Integrative Biology and Physiology, University of California, Los Angeles, California
| | - James N Weiss
- UCLA Cardiovascular Research Laboratory; Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California; Department of Integrative Biology and Physiology, University of California, Los Angeles, California; Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, California
| | - Zhilin Qu
- UCLA Cardiovascular Research Laboratory; Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, California.
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