1
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Mushtaq I, Hsieh TH, Chen YC, Kao YH, Chen YJ. MicroRNA-452-5p regulates fibrogenesis via targeting TGF-β/SMAD4 axis in SCN5A-knockdown human cardiac fibroblasts. iScience 2024; 27:110084. [PMID: 38883840 PMCID: PMC11179076 DOI: 10.1016/j.isci.2024.110084] [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: 11/28/2023] [Revised: 04/20/2024] [Accepted: 05/20/2024] [Indexed: 06/18/2024] Open
Abstract
The mutated SCN5A gene encoding defective Nav1.5 protein causes arrhythmic ailments and is associated with enhanced cardiac fibrosis. This study investigated whether SCN5A mutation directly affects cardiac fibroblasts and explored how defective SCN5A relates to cardiac fibrosis. SCN5A knockdown (SCN5AKD) human cardiac fibroblasts (HCF) had higher collagen, α-SMA, and fibronectin expressions. Micro-RNA deep sequencing and qPCR analysis revealed the downregulation of miR-452-5p and bioinformatic analysis divulged maladaptive upregulation of transforming growth factor β (TGF-β) signaling in SCN5AKD HCF. Luciferase reporter assays validated miR-452-5p targets SMAD4 in SCN5AKD HCF. Moreover, miR-452-5p mimic transfection in SCN5AKD HCF or AAV9-mediated miR-452-5p delivery in isoproterenol-induced heart failure (HF) rats, resulted in the attenuation of TGF-β signaling and fibrogenesis. The exogenous miR-452-5p significantly improved the poor cardiac function in HF rats. In conclusion, miR-452-5p regulates cardiac fibrosis progression by targeting the TGF-β/SMAD4 axis under the loss of the SCN5A gene.
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Affiliation(s)
- Iqra Mushtaq
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tsung-Han Hsieh
- Joint Biobank, Office of Human Research, Taipei Medical University, Taipei, Taiwan
| | - Yao-Chang Chen
- Department of Biomedical Engineering, National Defense Medical Center, Taipei, Taiwan
| | - Yu-Hsun Kao
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Medical Education and Research, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yi-Jen Chen
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Cardiovascular Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Taipei Heart Institute, Taipei Medical University, Taipei, Taiwan
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2
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Chrispin J, Merchant FM, Lakdawala NK, Wu KC, Tomaselli GF, Navara R, Torbey E, Ambardekar AV, Kabra R, Arbustini E, Narula J, Guglin M, Albert CM, Chugh SS, Trayanova N, Cheung JW. Risk of Arrhythmic Death in Patients With Nonischemic Cardiomyopathy: JACC Review Topic of the Week. J Am Coll Cardiol 2023; 82:735-747. [PMID: 37587585 DOI: 10.1016/j.jacc.2023.05.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 04/21/2023] [Accepted: 05/30/2023] [Indexed: 08/18/2023]
Abstract
Nonischemic cardiomyopathy (NICM) is common and patients are at significant risk for early mortality secondary to ventricular arrhythmias. Current guidelines recommend implantable cardioverter-defibrillator (ICD) therapy to decrease sudden cardiac death (SCD) in patients with heart failure and reduced left ventricular ejection fraction. However, in randomized clinical trials comprised solely of patients with NICM, primary prevention ICDs did not confer significant mortality benefit. Moreover, left ventricular ejection fraction has limited sensitivity and specificity for predicting SCD. Therefore, precise risk stratification algorithms are needed to define those at the highest risk of SCD. This review examines mechanisms of sudden arrhythmic death in patients with NICM, discusses the role of ICD therapy and treatment of heart failure for prevention of SCD in patients with NICM, examines the role of cardiac magnetic resonance imaging and computational modeling for SCD risk stratification, and proposes new strategies to guide future clinical trials on SCD risk assessment in patients with NICM.
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Affiliation(s)
- Jonathan Chrispin
- Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
| | | | - Neal K Lakdawala
- Division of Cardiovascular Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Katherine C Wu
- Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Gordon F Tomaselli
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Rachita Navara
- Division of Cardiac Electrophysiology, University of California, San Fransisco, California, USA
| | - Estelle Torbey
- Division of Electrophysiology, Brown University, Providence, Rhode Island, USA
| | - Amrut V Ambardekar
- Department of Medicine, Division of Cardiology, University of Colorado, Aurora, Colorado, USA
| | - Rajesh Kabra
- Kansas City Heart Rhythm Institute, Overland Park, Kansas, USA
| | - Eloisa Arbustini
- Center for Inherited Cardiovascular Diseases, IRCCS Foundation Policlinico San Matteo, Pavia, Italy
| | - Jagat Narula
- McGovern Medical School at the University of Texas Health Science Center, Houston, Texas, USA
| | - Maya Guglin
- Advanced Heart Failure and Transplant, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Christine M Albert
- Cardiac Electrohysiology, Cedars Sinai Smidt Heart Institute, Los Angeles, California, USA
| | - Sumeet S Chugh
- Cardiac Electrohysiology, Cedars Sinai Smidt Heart Institute, Los Angeles, California, USA
| | - Natalia Trayanova
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jim W Cheung
- Division of Cardiology, Weill Cornell Medicine, New York, New York, USA
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3
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Dehghani K, Stanek A, Bagherabadi A, Atashi F, Beygi M, Hooshmand A, Hamedi P, Farhang M, Bagheri S, Zolghadri S. CCND1 Overexpression in Idiopathic Dilated Cardiomyopathy: A Promising Biomarker? Genes (Basel) 2023; 14:1243. [PMID: 37372424 DOI: 10.3390/genes14061243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/05/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Cardiomyopathy, a disorder of electrical or heart muscle function, represents a type of cardiac muscle failure and culminates in severe heart conditions. The prevalence of dilated cardiomyopathy (DCM) is higher than that of other types (hypertrophic cardiomyopathy and restrictive cardiomyopathy) and causes many deaths. Idiopathic dilated cardiomyopathy (IDCM) is a type of DCM with an unknown underlying cause. This study aims to analyze the gene network of IDCM patients to identify disease biomarkers. Data were first extracted from the Gene Expression Omnibus (GEO) dataset and normalized based on the RMA algorithm (Bioconductor package), and differentially expressed genes were identified. The gene network was mapped on the STRING website, and the data were transferred to Cytoscape software to determine the top 100 genes. In the following, several genes, including VEGFA, IGF1, APP, STAT1, CCND1, MYH10, and MYH11, were selected for clinical studies. Peripheral blood samples were taken from 14 identified IDCM patients and 14 controls. The RT-PCR results revealed no significant differences in the expression of the genes APP, MYH10, and MYH11 between the two groups. By contrast, the STAT1, IGF1, CCND1, and VEGFA genes were overexpressed in patients more than in controls. The highest expression was found for VEGFA, followed by CCND1 (p < 0.001). Overexpression of these genes may contribute to disease progression in patients with IDCM. However, more patients and genes need to be analyzed in order to achieve more robust results.
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Affiliation(s)
- Khatereh Dehghani
- Department of Cardiology, Jahrom University of Medical Sciences, Jahrom 7414846199, Iran
| | - Agata Stanek
- Department and Clinic of Internal Medicine, Angiology and Physical Medicine, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, Batorego 15 Street, 41-902 Bytom, Poland
| | - Arash Bagherabadi
- Department of Biology, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil 5619911367, Iran
| | - Fatemeh Atashi
- Faculty of Medicine, Jahrom University of Medical Sciences, Jahrom 7414846199, Iran
| | - Mohammad Beygi
- Department of Agricultural Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan 8415683111, Iran
| | - Amirreza Hooshmand
- Department of Molecular and Cellular Sciences, Faculty of Advanced Sciences & Technology, Tehran Medical Sciences, Islamic Azad University, Tehran 1916893813, Iran
| | - Pezhman Hamedi
- Research Center, Department of Medical Laboratory Sciences, Faculty of Medicine, Jahrom University of Medical Sciences, Jahrom 7414846199, Iran
| | - Mohsen Farhang
- Molecular Study and Diagnostic Center, Jahrom University of Medical Sciences, Jahrom 7414846199, Iran
| | - Soghra Bagheri
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah 6714415185, Iran
| | - Samaneh Zolghadri
- Department of Biology, Jahrom Branch, Islamic Azad University, Jahrom 7414785318, Iran
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4
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Liu M, Kang GJ, Dudley SC. Preventing unfolded protein response-induced ion channel dysregulation to treat arrhythmias. Trends Mol Med 2022; 28:443-451. [DOI: 10.1016/j.molmed.2022.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 01/15/2023]
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5
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Kim JS, Choi SW, Park YG, Kim SJ, Choi CH, Cha MJ, Chang JH. Impact of High-Dose Irradiation on Human iPSC-Derived Cardiomyocytes Using Multi-Electrode Arrays: Implications for the Antiarrhythmic Effects of Cardiac Radioablation. Int J Mol Sci 2021; 23:351. [PMID: 35008778 PMCID: PMC8745341 DOI: 10.3390/ijms23010351] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 12/19/2022] Open
Abstract
Cardiac radioablation is emerging as an alternative option for refractory ventricular arrhythmias. However, the immediate acute effect of high-dose irradiation on human cardiomyocytes remains poorly known. We measured the electrical activities of human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) upon irradiation with 0, 20, 25, 30, 40, and 50 Gy using a multi-electrode array, and cardiomyocyte function gene levels were evaluated. iPSC-CMs showed to recover their electrophysiological activities (total active electrode, spike amplitude and slope, and corrected field potential duration) within 3-6 h from the acute effects of high-dose irradiation. The beat rate immediately increased until 3 h after irradiation, but it steadily decreased afterward. Conduction velocity slowed in cells irradiated with ≥25 Gy until 6-12 h and recovered within 24 h; notably, 20 and 25 Gy-treated groups showed subsequent continuous increase. At day 7 post-irradiation, except for cTnT, cardiomyocyte function gene levels increased with increasing irradiation dose, but uniquely peaked at 25-30 Gy. Altogether, high-dose irradiation immediately and reversibly modifies the electrical conduction of cardiomyocytes. Thus, compensatory mechanisms at the cellular level may be activated after the high-dose irradiation acute effects, thereby, contributing to the immediate antiarrhythmic outcome of cardiac radioablation for refractory ventricular arrhythmias.
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Affiliation(s)
- Jae Sik Kim
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul 03080, Korea; (J.S.K.); (C.H.C.)
- Department of Radiation Oncology, Kyung Hee University Hospital at Gangdong, Seoul 05278, Korea
| | - Seong Woo Choi
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Korea;
| | - Yun-Gwi Park
- Stem Cell Research Institute, T&R Biofab Co., Ltd., Siheung 15073, Korea;
| | - Sung Joon Kim
- Department of Physiology & Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 03080, Korea;
| | - Chang Heon Choi
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul 03080, Korea; (J.S.K.); (C.H.C.)
- Department of Radiation Oncology, Seoul National University Hospital, Seoul 03080, Korea
| | - Myung-Jin Cha
- Division of Cardiology, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Ji Hyun Chang
- Department of Radiation Oncology, Seoul National University College of Medicine, Seoul 03080, Korea; (J.S.K.); (C.H.C.)
- Department of Radiation Oncology, Seoul National University Hospital, Seoul 03080, Korea
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6
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Husti Z, Varró A, Baczkó I. Arrhythmogenic Remodeling in the Failing Heart. Cells 2021; 10:cells10113203. [PMID: 34831426 PMCID: PMC8623396 DOI: 10.3390/cells10113203] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 12/12/2022] Open
Abstract
Chronic heart failure is a clinical syndrome with multiple etiologies, associated with significant morbidity and mortality. Cardiac arrhythmias, including ventricular tachyarrhythmias and atrial fibrillation, are common in heart failure. A number of cardiac diseases including heart failure alter the expression and regulation of ion channels and transporters leading to arrhythmogenic electrical remodeling. Myocardial hypertrophy, fibrosis and scar formation are key elements of arrhythmogenic structural remodeling in heart failure. In this article, the mechanisms responsible for increased arrhythmia susceptibility as well as the underlying changes in ion channel, transporter expression and function as well as alterations in calcium handling in heart failure are discussed. Understanding the mechanisms of arrhythmogenic remodeling is key to improving arrhythmia management and the prevention of sudden cardiac death in patients with heart failure.
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Affiliation(s)
- Zoltán Husti
- Department of Pharmacology and Pharmacotherapy, University of Szeged, 6720 Szeged, Hungary; (Z.H.); (A.V.)
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6720 Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, 6720 Szeged, Hungary; (Z.H.); (A.V.)
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6720 Szeged, Hungary
- ELKH-SZTE Research Group for Cardiovascular Pharmacology, Eötvös Loránd Research Network, 6720 Szeged, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, University of Szeged, 6720 Szeged, Hungary; (Z.H.); (A.V.)
- Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, 6720 Szeged, Hungary
- Correspondence:
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7
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Zhang DM, Navara R, Yin T, Szymanski J, Goldsztejn U, Kenkel C, Lang A, Mpoy C, Lipovsky CE, Qiao Y, Hicks S, Li G, Moore KMS, Bergom C, Rogers BE, Robinson CG, Cuculich PS, Schwarz JK, Rentschler SL. Cardiac radiotherapy induces electrical conduction reprogramming in the absence of transmural fibrosis. Nat Commun 2021; 12:5558. [PMID: 34561429 PMCID: PMC8463558 DOI: 10.1038/s41467-021-25730-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 08/25/2021] [Indexed: 02/08/2023] Open
Abstract
Cardiac radiotherapy (RT) may be effective in treating heart failure (HF) patients with refractory ventricular tachycardia (VT). The previously proposed mechanism of radiation-induced fibrosis does not explain the rapidity and magnitude with which VT reduction occurs clinically. Here, we demonstrate in hearts from RT patients that radiation does not achieve transmural fibrosis within the timeframe of VT reduction. Electrophysiologic assessment of irradiated murine hearts reveals a persistent supraphysiologic electrical phenotype, mediated by increases in NaV1.5 and Cx43. By sequencing and transgenic approaches, we identify Notch signaling as a mechanistic contributor to NaV1.5 upregulation after RT. Clinically, RT was associated with increased NaV1.5 expression in 1 of 1 explanted heart. On electrocardiogram (ECG), post-RT QRS durations were shortened in 13 of 19 patients and lengthened in 5 patients. Collectively, this study provides evidence for radiation-induced reprogramming of cardiac conduction as a potential treatment strategy for arrhythmia management in VT patients.
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Affiliation(s)
- David M Zhang
- Center for Noninvasive Cardiac Radioablation, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Rachita Navara
- Center for Noninvasive Cardiac Radioablation, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Tiankai Yin
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Jeffrey Szymanski
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Uri Goldsztejn
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Camryn Kenkel
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Adam Lang
- Department of Pathology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Cedric Mpoy
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Catherine E Lipovsky
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Developmental Biology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Yun Qiao
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Stephanie Hicks
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Gang Li
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Kaitlin M S Moore
- Center for Noninvasive Cardiac Radioablation, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Carmen Bergom
- Center for Noninvasive Cardiac Radioablation, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Buck E Rogers
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Clifford G Robinson
- Center for Noninvasive Cardiac Radioablation, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Phillip S Cuculich
- Center for Noninvasive Cardiac Radioablation, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Julie K Schwarz
- Center for Noninvasive Cardiac Radioablation, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA
| | - Stacey L Rentschler
- Center for Noninvasive Cardiac Radioablation, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA.
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA.
- Department of Biomedical Engineering, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA.
- Department of Developmental Biology, Washington University in St. Louis, School of Medicine, Saint Louis, MO, USA.
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8
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Zhang DM, Szymanski J, Bergom C, Cuculich PS, Robinson CG, Schwarz JK, Rentschler SL. Leveraging Radiobiology for Arrhythmia Management: A New Treatment Paradigm? Clin Oncol (R Coll Radiol) 2021; 33:723-734. [PMID: 34535357 DOI: 10.1016/j.clon.2021.09.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 08/04/2021] [Accepted: 09/01/2021] [Indexed: 01/01/2023]
Abstract
Radiation therapy is a well-established approach for safely and non-invasively treating solid tumours and benign diseases with high precision and accuracy. Cardiac radiation therapy has recently emerged as a non-invasive treatment option for the management of refractory ventricular tachycardia. Here we summarise existing clinical and preclinical literature surrounding cardiac radiobiology and discuss how these studies may inform basic and translational research, as well as clinical treatment paradigms in the management of arrhythmias.
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Affiliation(s)
- D M Zhang
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - J Szymanski
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - C Bergom
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - P S Cuculich
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA; Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - C G Robinson
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA; Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - J K Schwarz
- Department of Radiation Oncology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA
| | - S L Rentschler
- Department of Medicine, Cardiovascular Division, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA; Department of Biomedical Engineering, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA; Department of Developmental Biology, Washington University in St. Louis, School of Medicine, Saint Louis, Missouri, USA.
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9
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Marian AJ, Asatryan B, Wehrens XHT. Genetic basis and molecular biology of cardiac arrhythmias in cardiomyopathies. Cardiovasc Res 2021; 116:1600-1619. [PMID: 32348453 DOI: 10.1093/cvr/cvaa116] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/09/2020] [Accepted: 04/21/2020] [Indexed: 12/19/2022] Open
Abstract
Cardiac arrhythmias are common, often the first, and sometimes the life-threatening manifestations of hereditary cardiomyopathies. Pathogenic variants in several genes known to cause hereditary cardiac arrhythmias have also been identified in the sporadic cases and small families with cardiomyopathies. These findings suggest a shared genetic aetiology of a subset of hereditary cardiomyopathies and cardiac arrhythmias. The concept of a shared genetic aetiology is in accord with the complex and exquisite interplays that exist between the ion currents and cardiac mechanical function. However, neither the causal role of cardiac arrhythmias genes in cardiomyopathies is well established nor the causal role of cardiomyopathy genes in arrhythmias. On the contrary, secondary changes in ion currents, such as post-translational modifications, are common and contributors to the pathogenesis of arrhythmias in cardiomyopathies through altering biophysical and functional properties of the ion channels. Moreover, structural changes, such as cardiac hypertrophy, dilatation, and fibrosis provide a pro-arrhythmic substrate in hereditary cardiomyopathies. Genetic basis and molecular biology of cardiac arrhythmias in hereditary cardiomyopathies are discussed.
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Affiliation(s)
- Ali J Marian
- Department of Medicine, Center for Cardiovascular Genetics, Institute of Molecular Medicine, University of Texas Health Sciences Center at Houston, 6770 Bertner Street, Suite C900A, Houston, TX 77030, USA
| | - Babken Asatryan
- Department of Cardiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Xander H T Wehrens
- Department of Biophysics and Molecular Physiology, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
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10
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Liu M, Liu H, Parthiban P, Kang GJ, Shi G, Feng F, Zhou A, Gu L, Karnopp C, Tolkacheva EG, Dudley SC. Inhibition of the unfolded protein response reduces arrhythmic risk after myocardial infarction. J Clin Invest 2021; 131:e147836. [PMID: 34324437 DOI: 10.1172/jci147836] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 07/28/2021] [Indexed: 11/17/2022] Open
Abstract
Ischemic cardiomyopathy is associated with an increased risk of sudden death, activation of the unfolded protein response (UPR), and reductions in multiple cardiac ion channels. When activated, the protein kinase-like ER kinase (PERK) branch of the UPR reduces protein translation and abundance. We hypothesized that PERK inhibition could prevent ion channel downregulation and reduce arrhythmic risk after myocardial infarct (MI). MI induced by coronary artery ligation resulted in mice exhibited reduced ion channel levels, ventricular tachycardia (VT), and prolonged corrected intervals between the Q and T waves of the ECGs (QTc). Protein levels of major cardiac ion channels were decreased. MI cardiomyocytes showed significantly prolonged action potential duration and decreased maximum upstroke velocity. Cardiac-specific PERK knockout (PERKKO) reduced electrical remodeling in response to MI with shortened QTc intervals, less VT episodes, and higher survival rates (P<0.05 vs. MI). Pharmacological PERK inhibition had similar effects. In conclusion, activated PERK during MI contributed to arrhythmic risk by downregulation of select cardiac ion channels. PERK inhibition prevented these changes and reduced arrhythmic risk. These results suggest that ion channel downregulation during MI is a fundamental arrhythmic mechanism and maintaining ion channel levels is antiarrhythmic.
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Affiliation(s)
- Man Liu
- Lillehei Heart Institute, University of Minnesota, Minneapolis, United States of America
| | - Hong Liu
- Lillehei Heart Institute, University of Minnesota, Minneapolis, United States of America
| | - Preethy Parthiban
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, United States of America
| | - Gyeoung-Jin Kang
- Lillehei Heart Institute, University of Minnesota, Minneapolis, United States of America
| | - Guangbin Shi
- Department of Medicine, Brown University, Providence, United States of America
| | - Feng Feng
- Lillehei Heart Institute, University of Minnesota, Minneapolis, United States of America
| | - Anyu Zhou
- Department of Medicine, Brown University, Providence, United States of America
| | - Lianzhi Gu
- Lillehei Heart Institute, University of Minnesota, Minneapolis, United States of America
| | - Courtney Karnopp
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, United States of America
| | - Elena G Tolkacheva
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, United States of America
| | - Samuel C Dudley
- Lillehei Heart Institute, University of Minnesota, Minneapolis, United States of America
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11
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Imoto K, Sakai Y, Okada M, Otani K, Yamawaki H. A single injection of periostin decreases cardiac voltage-gated Na + channel in rat ventricles. J Vet Med Sci 2021; 83:997-1003. [PMID: 33952782 PMCID: PMC8267192 DOI: 10.1292/jvms.21-0040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Changes in electrophysiological properties, such as ion channel expression and activity,
are closely related to arrhythmogenesis during heart failure (HF). However, a causative
factor for the electrical remodeling in HF has not been determined. Periostin (POSTN), a
matricellular protein, is increased in heart tissues of patients with HF. In the present
study, we investigated whether a single injection of POSTN affects the
electrophysiological properties in rat ventricles. After male Wistar rats were
intravenously injected with recombinant rat POSTN (64 µg/kg, 24 hr), electrocardiogram
(ECG) was recorded. Whole-cell patch clamp was performed to measure action potential (AP)
and Na+ current (INa) in isolated ventricular
myocytes. Protein expression of cardiac voltage-gated Na+ channel
(NaV1.5) in isolated ventricles was examined by Western blotting. In ECG,
POSTN-injection significantly increased RS height. POSTN-injection significantly delayed
time to peak in AP and decreased INa in the isolated
ventricular myocytes. POSTN-injection decreased NaV1.5 expression in the
isolated ventricles. It was confirmed that POSTN (1 µg/ml, 24 hr) decreased
INa and NaV1.5 protein expression in neonatal rat
ventricular myocytes. This study for the first time demonstrated that a single injection
of POSTN in rats decreased INa by suppressing
NaV1.5 expression in the ventricular myocytes, which was accompanied by a
prolongation of time to peak in AP and an increase of RS height in ECG.
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Affiliation(s)
- Keisuke Imoto
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada-shi, Aomori 034-8628, Japan
| | - Yuho Sakai
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada-shi, Aomori 034-8628, Japan
| | - Muneyoshi Okada
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada-shi, Aomori 034-8628, Japan
| | - Kosuke Otani
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada-shi, Aomori 034-8628, Japan
| | - Hideyuki Yamawaki
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Higashi 23-35-1, Towada-shi, Aomori 034-8628, Japan
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12
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Lorenzini M, Burel S, Lesage A, Wagner E, Charrière C, Chevillard PM, Evrard B, Maloney D, Ruff KM, Pappu RV, Wagner S, Nerbonne JM, Silva JR, Townsend RR, Maier LS, Marionneau C. Proteomic and functional mapping of cardiac NaV1.5 channel phosphorylation sites. J Gen Physiol 2021; 153:211660. [PMID: 33410863 PMCID: PMC7797897 DOI: 10.1085/jgp.202012646] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 10/23/2020] [Accepted: 12/03/2020] [Indexed: 12/16/2022] Open
Abstract
Phosphorylation of the voltage-gated Na+ (NaV) channel NaV1.5 regulates cardiac excitability, yet the phosphorylation sites regulating its function and the underlying mechanisms remain largely unknown. Using a systematic, quantitative phosphoproteomic approach, we analyzed NaV1.5 channel complexes purified from nonfailing and failing mouse left ventricles, and we identified 42 phosphorylation sites on NaV1.5. Most sites are clustered, and three of these clusters are highly phosphorylated. Analyses of phosphosilent and phosphomimetic NaV1.5 mutants revealed the roles of three phosphosites in regulating NaV1.5 channel expression and gating. The phosphorylated serines S664 and S667 regulate the voltage dependence of channel activation in a cumulative manner, whereas the nearby S671, the phosphorylation of which is increased in failing hearts, regulates cell surface NaV1.5 expression and peak Na+ current. No additional roles could be assigned to the other clusters of phosphosites. Taken together, our results demonstrate that ventricular NaV1.5 is highly phosphorylated and that the phosphorylation-dependent regulation of NaV1.5 channels is highly complex, site specific, and dynamic.
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Affiliation(s)
- Maxime Lorenzini
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Sophie Burel
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Adrien Lesage
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Emily Wagner
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - Camille Charrière
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Pierre-Marie Chevillard
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Bérangère Evrard
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
| | - Dan Maloney
- Bioinformatics Solutions Inc., Waterloo, Ontario, Canada
| | - Kiersten M Ruff
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - Rohit V Pappu
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - Stefan Wagner
- Department of Internal Medicine II, University Heart Center, University Hospital Regensburg, Regensburg, Germany
| | - Jeanne M Nerbonne
- Department of Developmental Biology, Washington University Medical School, St. Louis, MO.,Department of Medicine, Washington University Medical School, St. Louis, MO
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO
| | - R Reid Townsend
- Department of Medicine, Washington University Medical School, St. Louis, MO.,Department of Cell Biology and Physiology, Washington University Medical School, St. Louis, MO
| | - Lars S Maier
- Department of Internal Medicine II, University Heart Center, University Hospital Regensburg, Regensburg, Germany
| | - Céline Marionneau
- Université de Nantes, Centre national de la recherche scientifique, Institut National de la Santé et de la Recherche Médicale, l'Institut du thorax, Nantes, France
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13
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Turan NN, Moshal KS, Roder K, Baggett BC, Kabakov AY, Dhakal S, Teramoto R, Chiang DYE, Zhong M, Xie A, Lu Y, Dudley SC, MacRae CA, Karma A, Koren G. The endosomal trafficking regulator LITAF controls the cardiac Nav1.5 channel via the ubiquitin ligase NEDD4-2. J Biol Chem 2020; 295:18148-18159. [PMID: 33093176 PMCID: PMC7939464 DOI: 10.1074/jbc.ra120.015216] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/20/2020] [Indexed: 01/14/2023] Open
Abstract
The QT interval is a recording of cardiac electrical activity. Previous genome-wide association studies identified genetic variants that modify the QT interval upstream of LITAF (lipopolysaccharide-induced tumor necrosis factor-α factor), a protein encoding a regulator of endosomal trafficking. However, it was not clear how LITAF might impact cardiac excitation. We investigated the effect of LITAF on the voltage-gated sodium channel Nav1.5, which is critical for cardiac depolarization. We show that overexpressed LITAF resulted in a significant increase in the density of Nav1.5-generated voltage-gated sodium current INa and Nav1.5 surface protein levels in rabbit cardiomyocytes and in HEK cells stably expressing Nav1.5. Proximity ligation assays showed co-localization of endogenous LITAF and Nav1.5 in cardiomyocytes, whereas co-immunoprecipitations confirmed they are in the same complex when overexpressed in HEK cells. In vitro data suggest that LITAF interacts with the ubiquitin ligase NEDD4-2, a regulator of Nav1.5. LITAF overexpression down-regulated NEDD4-2 in cardiomyocytes and HEK cells. In HEK cells, LITAF increased ubiquitination and proteasomal degradation of co-expressed NEDD4-2 and significantly blunted the negative effect of NEDD4-2 on INa We conclude that LITAF controls cardiac excitability by promoting degradation of NEDD4-2, which is essential for removal of surface Nav1.5. LITAF-knockout zebrafish showed increased variation in and a nonsignificant 15% prolongation of action potential duration. Computer simulations using a rabbit-cardiomyocyte model demonstrated that changes in Ca2+ and Na+ homeostasis are responsible for the surprisingly modest action potential duration shortening. These computational data thus corroborate findings from several genome-wide association studies that associated LITAF with QT interval variation.
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Affiliation(s)
- Nilüfer N Turan
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Karni S Moshal
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Karim Roder
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Brett C Baggett
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Anatoli Y Kabakov
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Saroj Dhakal
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - Ryota Teramoto
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - David Yi-Eng Chiang
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mingwang Zhong
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - An Xie
- Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Yichun Lu
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| | - Samuel C Dudley
- Cardiovascular Division, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Calum A MacRae
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Alain Karma
- Physics Department and Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, Massachusetts, USA
| | - Gideon Koren
- Cardiovascular Research Center, Division of Cardiology, Department of Medicine, Rhode Island Hospital, Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA.
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14
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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15
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Williams AL, Khadka VS, Anagaran MCT, Lee K, Avelar A, Deng Y, Shohet RV. miR-125 family regulates XIRP1 and FIH in response to myocardial infarction. Physiol Genomics 2020; 52:358-368. [PMID: 32716698 DOI: 10.1152/physiolgenomics.00041.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
MicroRNAs (miRNAs) are powerful regulators of protein expression. Many play important roles in cardiac development and disease. While several miRNAs and targets have been well characterized, the abundance of miRNAs and the numerous potential targets for each suggest that the vast majority of these interactions have yet to be described. The goal of this study was to characterize miRNA expression in the mouse heart after coronary artery ligation (LIG) and identify novel mRNA targets altered during the initial response to ischemic stress. We performed small RNA sequencing (RNA-Seq) of ischemic heart tissue 1 day and 3 days after ligation and identified 182 differentially expressed miRNAs. We then selected relevant mRNA targets from all potential targets by correlating miRNA and mRNA expression from a corresponding RNA-Seq data set. From this analysis we chose to focus, as proof of principle, on two miRNAs from the miR-125 family, miR-125a and miR-351, and two of their potential mRNA targets, Xin actin-binding repeat-containing protein 1 (XIRP1) and factor inhibiting hypoxia-inducible factor (FIH). We found miR-125a to be less abundant and XIRP1 more abundant after ligation. In contrast, the related murine miRNA miR-351 was substantially upregulated in response to ischemic injury, and FIH expression correspondingly decreased. Luciferase reporter assays confirmed direct interactions between these miRNAs and targets. In summary, we utilized a correlative analysis strategy combining miRNA and mRNA expression data to identify functional miRNA-mRNA relationships in the heart after ligation. These findings provide insight into the response to ischemic injury and suggest future therapeutic targets.
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Affiliation(s)
- Allison Lesher Williams
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Vedbar S Khadka
- Bioinformatics Core, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Ma C T Anagaran
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Katie Lee
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Abigail Avelar
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Youping Deng
- Bioinformatics Core, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
| | - Ralph V Shohet
- Center for Cardiovascular Research, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii
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16
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Munger MA, Olğar Y, Koleske ML, Struckman HL, Mandrioli J, Lou Q, Bonila I, Kim K, Ramos Mondragon R, Priori SG, Volpe P, Valdivia HH, Biskupiak J, Carnes CA, Veeraraghavan R, Györke S, Radwański PB. Tetrodotoxin-Sensitive Neuronal-Type Na + Channels: A Novel and Druggable Target for Prevention of Atrial Fibrillation. J Am Heart Assoc 2020; 9:e015119. [PMID: 32468902 PMCID: PMC7429002 DOI: 10.1161/jaha.119.015119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Atrial fibrillation (AF) is a comorbidity associated with heart failure and catecholaminergic polymorphic ventricular tachycardia. Despite the Ca2+‐dependent nature of both of these pathologies, AF often responds to Na+ channel blockers. We investigated how targeting interdependent Na+/Ca2+ dysregulation might prevent focal activity and control AF. Methods and Results We studied AF in 2 models of Ca2+‐dependent disorders, a murine model of catecholaminergic polymorphic ventricular tachycardia and a canine model of chronic tachypacing‐induced heart failure. Imaging studies revealed close association of neuronal‐type Na+ channels (nNav) with ryanodine receptors and Na+/Ca2+ exchanger. Catecholamine stimulation induced cellular and in vivo atrial arrhythmias in wild‐type mice only during pharmacological augmentation of nNav activity. In contrast, catecholamine stimulation alone was sufficient to elicit atrial arrhythmias in catecholaminergic polymorphic ventricular tachycardia mice and failing canine atria. Importantly, these were abolished by acute nNav inhibition (tetrodotoxin or riluzole) implicating Na+/Ca2+ dysregulation in AF. These findings were then tested in 2 nonrandomized retrospective cohorts: an amyotrophic lateral sclerosis clinic and an academic medical center. Riluzole‐treated patients adjusted for baseline characteristics evidenced significantly lower incidence of arrhythmias including new‐onset AF, supporting the preclinical results. Conclusions These data suggest that nNaVs mediate Na+‐Ca2+ crosstalk within nanodomains containing Ca2+ release machinery and, thereby, contribute to AF triggers. Disruption of this mechanism by nNav inhibition can effectively prevent AF arising from diverse causes.
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Affiliation(s)
- Mark A Munger
- Departments of Pharmacotherapy and Internal Medicine University of Utah Health Sciences Center Salt Lake City UT
| | - Yusuf Olğar
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH
| | - Megan L Koleske
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH
| | - Heather L Struckman
- Department of Biomedical Engineering College of Engineering The Ohio State University Columbus OH
| | - Jessica Mandrioli
- Department of Neuroscience St. Agostino Estense Hospital Azienda Ospedaliero Universitaria di Modena Italy
| | - Qing Lou
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
| | - Ingrid Bonila
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
| | - Kibum Kim
- Department of Pharmacotherapy University of Utah Health Sciences Center Salt Lake City UT
| | - Roberto Ramos Mondragon
- Department of Internal Medicine and of Molecular & Integrative Physiology University of Michigan Ann Arbor MI
| | - Silvia G Priori
- Molecular Cardiology Istituti Clinici Scientifici Maugeri IRCCS University of Pavia Italy.,Department of Molecular Medicine University of Pavia Italy
| | - Pompeo Volpe
- Department of Biomedical Sciences University of Padova Italy
| | - Héctor H Valdivia
- Department of Internal Medicine and of Molecular & Integrative Physiology University of Michigan Ann Arbor MI
| | - Joseph Biskupiak
- Department of Pharmacotherapy University of Utah Health Sciences Center Salt Lake City UT
| | - Cynthia A Carnes
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH
| | - Rengasayee Veeraraghavan
- Department of Biomedical Engineering College of Engineering The Ohio State University Columbus OH.,Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH
| | - Sándor Györke
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
| | - Przemysław B Radwański
- Dorothy M. Davis Heart and Lung Research Institute College of Medicine The Ohio State University Wexner Medical Center Columbus OH.,Division of Pharmacy Practice and Sciences College of Pharmacy The Ohio State University Columbus OH.,Department of Physiology and Cell Biology College of Medicine The Ohio State University Columbus OH
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17
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Dybkova N, Ahmad S, Pabel S, Tirilomis P, Hartmann N, Fischer TH, Bengel P, Tirilomis T, Ljubojevic S, Renner A, Gummert J, Ellenberger D, Wagner S, Frey N, Maier LS, Streckfuss-Bömeke K, Hasenfuss G, Sossalla S. Differential regulation of sodium channels as a novel proarrhythmic mechanism in the human failing heart. Cardiovasc Res 2019; 114:1728-1737. [PMID: 29931291 DOI: 10.1093/cvr/cvy152] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 06/15/2018] [Indexed: 12/18/2022] Open
Abstract
Aims In heart failure (HF), enhanced persistent Na+ current (INaL) exerts detrimental effects on cellular electrophysiology and can induce arrhythmias. However, the underlying regulatory mechanisms remain unclear. Our aim was to potentially investigate the regulation and electrophysiological contribution of neuronal sodium channel NaV1.8 in failing human heart and eventually to reveal a novel anti-arrhythmic therapy. Methods and results By western blot, we found that NaV1.8 protein expression is significantly up-regulated, while of the predominant cardiac isoform NaV1.5 is inversely reduced in human HF. Furthermore, to investigate the relation of NaV1.8 regulation with the cellular proarrhythmic events, we performed comprehensive electrophysiology recordings and explore the effect of NaV1.8 on INaL, action potential duration (APD), Ca2+ spark frequency, and arrhythmia induction in human failing cardiomyocytes. NaV1.8 inhibition with the specific blockers A-803467 and PF-01247324 decreased INaL, abbreviated APD and reduced cellular-spontaneous Ca2+-release and proarrhythmic events in human failing cardiomyocytes. Consistently, in mouse cardiomyocytes stressed with isoproterenol, pharmacologic inhibition and genetically knockout of NaV1.8 (SCN10A-/-), were associated with reduced INaL and abbreviated APD. Conclusion We provide first evidence of differential regulation of NaV1.8 and NaV1.5 in the failing human myocardium and their contribution to arrhythmogenesis due to generation of INaL. We propose inhibition of NaV1.8 thus constitutes a promising novel approach for selective anti-arrhythmic therapy in HF.
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Affiliation(s)
- Nataliya Dybkova
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Shakil Ahmad
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Steffen Pabel
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Petros Tirilomis
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Nico Hartmann
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Thomas H Fischer
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Philipp Bengel
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Theodoros Tirilomis
- Department of Thoracic, Cardiac and Vascular Surgery, Georg-August University Goettingen, Germany
| | | | - André Renner
- Department of Thoracic, Cardiac and Vascular Surgery (Heart and Diabetes Center), North Rhine Westphalia, Bad Oeynhausen, Germany
| | - Jan Gummert
- Department of Thoracic, Cardiac and Vascular Surgery (Heart and Diabetes Center), North Rhine Westphalia, Bad Oeynhausen, Germany
| | - David Ellenberger
- Department of Medical Statistics, University Medical Center Goettingen, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Norbert Frey
- Department of Internal Medicine III, Molecular Cardiology and Angiology, University Medical Center, Campus Kiel, Schleswig-Holstein, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Germany
| | - Katrin Streckfuss-Bömeke
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Gerd Hasenfuss
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany
| | - Samuel Sossalla
- Clinic for Cardiology & Pneumology, Georg-August University Goettingen, DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Germany.,Department of Internal Medicine II, University Medical Center Regensburg, Germany
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18
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Ahmad S, Tirilomis P, Pabel S, Dybkova N, Hartmann N, Molina CE, Tirilomis T, Kutschka I, Frey N, Maier LS, Hasenfuss G, Streckfuss-Bömeke K, Sossalla S. The functional consequences of sodium channel Na V 1.8 in human left ventricular hypertrophy. ESC Heart Fail 2018; 6:154-163. [PMID: 30378291 PMCID: PMC6352890 DOI: 10.1002/ehf2.12378] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/18/2018] [Accepted: 10/10/2018] [Indexed: 01/15/2023] Open
Abstract
Aims In hypertrophy and heart failure, the proarrhythmic persistent Na+ current (INaL) is enhanced. We aimed to investigate the electrophysiological role of neuronal sodium channel NaV1.8 in human hypertrophied myocardium. Methods and results Myocardial tissue of 24 patients suffering from symptomatic severe aortic stenosis and concomitant significant afterload‐induced hypertrophy with preserved ejection fraction was used and compared with 12 healthy controls. We performed quantitative real‐time PCR and western blot and detected a significant up‐regulation of NaV1.8 mRNA (2.34‐fold) and protein expression (1.96‐fold) in human hypertrophied myocardium compared with healthy hearts. Interestingly, NaV1.5 protein expression was significantly reduced in parallel (0.60‐fold). Using whole‐cell patch‐clamp technique, we found that the prominent INaL was significantly reduced after addition of novel NaV1.8‐specific blockers either A‐803467 (30 nM) or PF‐01247324 (1 μM) in human hypertrophic cardiomyocytes. This clearly demonstrates the relevant contribution of NaV1.8 to this proarrhythmic current. We observed a significant action potential duration shortening and performed confocal microscopy, demonstrating a 50% decrease in proarrhythmic diastolic sarcoplasmic reticulum (SR)‐Ca2+ leak and SR‐Ca2+ spark frequency after exposure to both NaV1.8 inhibitors. Conclusions We show for the first time that the neuronal sodium channel NaV1.8 is up‐regulated on mRNA and protein level in the human hypertrophied myocardium. Furthermore, inhibition of NaV1.8 reduced augmented INaL, abbreviated the action potential duration, and decreased the SR‐Ca2+ leak. The findings of our study suggest that NaV1.8 could be a promising antiarrhythmic therapeutic target and merits further investigation.
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Affiliation(s)
- Shakil Ahmad
- Department of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany.,Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Petros Tirilomis
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Steffen Pabel
- Department of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Nataliya Dybkova
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Nico Hartmann
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Cristina E Molina
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Theodoros Tirilomis
- Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, Georg-August University Goettingen, Goettingen, Germany
| | - Ingo Kutschka
- Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, Georg-August University Goettingen, Goettingen, Germany
| | - Norbert Frey
- Department of Internal Medicine III, Molecular Cardiology and Angiology, University Medical Center, Schleswig-Holstein, Campus Kiel, Kiel, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany
| | - Gerd Hasenfuss
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Katrin Streckfuss-Bömeke
- Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Samuel Sossalla
- Department of Internal Medicine II, University Medical Center Regensburg, Regensburg, Germany.,Department of Cardiology and Pneumology, University Hospital, Georg-August University Goettingen, and DZHK (German Centre for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
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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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20
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Nassal DM, Wan X, Liu H, Maleski D, Ramirez-Navarro A, Moravec CS, Ficker E, Laurita KR, Deschênes I. KChIP2 is a core transcriptional regulator of cardiac excitability. eLife 2017; 6. [PMID: 28263709 PMCID: PMC5338919 DOI: 10.7554/elife.17304] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 02/19/2017] [Indexed: 11/18/2022] Open
Abstract
Arrhythmogenesis from aberrant electrical remodeling is a primary cause of death among patients with heart disease. Amongst a multitude of remodeling events, reduced expression of the ion channel subunit KChIP2 is consistently observed in numerous cardiac pathologies. However, it remains unknown if KChIP2 loss is merely a symptom or involved in disease development. Using rat and human derived cardiomyocytes, we identify a previously unobserved transcriptional capacity for cardiac KChIP2 critical in maintaining electrical stability. Through interaction with genetic elements, KChIP2 transcriptionally repressed the miRNAs miR-34b and miR-34c, which subsequently targeted key depolarizing (INa) and repolarizing (Ito) currents altered in cardiac disease. Genetically maintaining KChIP2 expression or inhibiting miR-34 under pathologic conditions restored channel function and moreover, prevented the incidence of reentrant arrhythmias. This identifies the KChIP2/miR-34 axis as a central regulator in developing electrical dysfunction and reveals miR-34 as a therapeutic target for treating arrhythmogenesis in heart disease. DOI:http://dx.doi.org/10.7554/eLife.17304.001 The heart pumps blood throughout the body to provide oxygen and nourishment. To do so, proteins in the heart create electrical signals that tell the heart muscles to contract in a coordinated manner. Heart disease can cause cells to lose control of the production or activity of these proteins, creating disorganized electrical signals called arrhythmias that interfere with the heart’s ability to pump. Sometimes these arrhythmias lead to sudden death. Researchers do not know exactly what triggers these changes in the heart’s normal electrical rhythms. This has made it difficult to develop strategies to prevent these disruptions or to fix them when they occur. By studying rat and human heart cells, Nassal et al. now show that a protein called KChIP2 stops working properly during heart disease. Most importantly, because of the decreased level of KChIP2 in heart disease, KChIP2 loses the ability to restrict the production of two microRNA molecules – a role that KChIP2 was not previously known to perform. This loss of activity sets off a cascade of signals that worsens the balance of electrical activity in the heart cells, creating arrhythmias. Treatments that restored proper levels of the fully working KChIP2 protein to the heart cells or that blocked the signals set off by a lack of KChIP2 returned the electrical activity of the cells back to normal. This also stopped the development of arrhythmias. Further studies are now needed to investigate whether these treatments have the same effects in living mammals. If effective, this could ultimately lead to new treatments for heart diseases and arrhythmias. DOI:http://dx.doi.org/10.7554/eLife.17304.002
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Affiliation(s)
- Drew M Nassal
- Heart and Vascular Research Center, Department of Medicine, Case Western Reserve University, Cleveland, United States.,Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, United States
| | - Xiaoping Wan
- Heart and Vascular Research Center, Department of Medicine, Case Western Reserve University, Cleveland, United States
| | - Haiyan Liu
- Heart and Vascular Research Center, Department of Medicine, Case Western Reserve University, Cleveland, United States
| | - Danielle Maleski
- Heart and Vascular Research Center, Department of Medicine, Case Western Reserve University, Cleveland, United States
| | - Angelina Ramirez-Navarro
- Heart and Vascular Research Center, Department of Medicine, Case Western Reserve University, Cleveland, United States
| | - Christine S Moravec
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, United States
| | - Eckhard Ficker
- Heart and Vascular Research Center, Department of Medicine, Case Western Reserve University, Cleveland, United States
| | - Kenneth R Laurita
- Heart and Vascular Research Center, Department of Medicine, Case Western Reserve University, Cleveland, United States
| | - Isabelle Deschênes
- Heart and Vascular Research Center, Department of Medicine, Case Western Reserve University, Cleveland, United States.,Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, United States
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Pre- and Delayed Treatments With Ranolazine Ameliorate Ventricular Arrhythmias and Nav1.5 Downregulation in Ischemic/Reperfused Rat Hearts. J Cardiovasc Pharmacol 2016; 68:269-279. [DOI: 10.1097/fjc.0000000000000412] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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22
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Liu M, Yang KC, Dudley SC. Cardiac Sodium Channel Mutations: Why so Many Phenotypes? CURRENT TOPICS IN MEMBRANES 2016; 78:513-59. [PMID: 27586294 DOI: 10.1016/bs.ctm.2015.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cardiac Na(+) channel (Nav1.5) conducts a depolarizing inward Na(+) current that is responsible for the generation of the upstroke Phase 0 of the action potential. In heart tissue, changes in Na(+) currents can affect conduction velocity and impulse propagation. The cardiac Nav1.5 is also involved in determination of the action potential duration, since some channels may reopen during the plateau phase, generating a persistent or late inward current. Mutations of cardiac Nav1.5 can induce gain or loss of channel function because of an increased late current or a decrease of peak current, respectively. Gain-of-function mutations cause Long QT syndrome type 3 and possibly atrial fibrillation, while loss-of-function channel mutations are associated with a wider variety of phenotypes, such as Brugada syndrome, cardiac conduction disease, dilated cardiomyopathy, and sick sinus node syndrome. The penetrance and phenotypes resulting from Nav1.5 mutations also vary with age, gender, body temperature, circadian rhythm, and between regions of the heart. This phenotypic variability makes it difficult to correlate genotype-phenotype. We propose that mutations are only one contributor to the phenotype and additional modifications on Nav1.5 lead to the phenotypic variability. Possible modifiers include other genetic variations and alterations in the life cycle of Nav1.5 such as gene transcription, RNA processing, translation, posttranslational modifications, trafficking, complex assembly, and degradation. In this chapter, we summarize potential modifiers of cardiac Nav1.5 that could help explain the clinically observed phenotypic variability. Consideration of these modifiers could help improve genotype-phenotype correlations and lead to new therapeutic strategies.
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Affiliation(s)
- M Liu
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - K-C Yang
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - S C Dudley
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
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23
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Abstract
Optimal cardiac function depends on proper timing of excitation and contraction in various regions of the heart, as well as on appropriate heart rate. This is accomplished via specialized electrical properties of various components of the system, including the sinoatrial node, atria, atrioventricular node, His-Purkinje system, and ventricles. Here we review the major regionally determined electrical properties of these cardiac regions and present the available data regarding the molecular and ionic bases of regional cardiac function and dysfunction. Understanding these differences is of fundamental importance for the investigation of arrhythmia mechanisms and pharmacotherapy.
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Affiliation(s)
- Daniel C Bartos
- Department of Pharmacology, University of California Davis, Davis, California, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, California, USA
| | - Crystal M Ripplinger
- Department of Pharmacology, University of California Davis, Davis, California, USA
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24
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Deletion of PDK1 causes cardiac sodium current reduction in mice. PLoS One 2015; 10:e0122436. [PMID: 25781322 PMCID: PMC4363661 DOI: 10.1371/journal.pone.0122436] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/14/2015] [Indexed: 01/01/2023] Open
Abstract
Background The AGC protein kinase family regulates multiple cellular functions. 3-phosphoinositide-dependent protein kinase-1 (PDK1) is involved in the pathogenesis of arrhythmia, and its downstream factor, Forkhead box O1 (Foxo1), negatively regulates the expression of the cardiac sodium channel, Nav1.5. Mice are known to die suddenly after PDK1 deletion within 11 weeks, but the underlying electrophysiological bases are unclear. Thus, the aim of this study was to investigate the potential mechanisms between PDK1 signaling pathway and cardiac sodium current. Methods and Results Using patch clamp and western blotting techniques, we investigated the role of the PDK1-Foxo1 pathway in PDK1 knockout mice and cultured cardiomyocytes. We found that PDK1 knockout mice undergo slower heart rate, prolonged QRS and QTc intervals and abnormal conduction within the first few weeks of birth. Furthermore, the peak sodium current is decreased by 33% in cells lacking PDK1. The phosphorylation of Akt (308T) and Foxo1 (24T) and the expression of Nav1.5 in the myocardium of PDK1-knockout mice are decreased, while the nuclear localization of Foxo1 is increased. The role of the PDK1-Foxo1 pathway in regulating Nav1.5 levels and sodium current density was verified using selective PDK1, Akt and Foxo1 inhibitors and isolated neonatal rat cardiomyocytes. Conclusion These results indicate that PDK1 participates in the dysregulation of electrophysiological basis by regulating the PDK1-Foxo1 pathway, which in turn regulates the expression of Nav1.5 and cardiac sodium channel function.
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25
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Mishra S, Reznikov V, Maltsev VA, Undrovinas NA, Sabbah HN, Undrovinas A. Contribution of sodium channel neuronal isoform Nav1.1 to late sodium current in ventricular myocytes from failing hearts. J Physiol 2014; 593:1409-27. [PMID: 25772296 DOI: 10.1113/jphysiol.2014.278259] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 10/03/2014] [Indexed: 01/06/2023] Open
Abstract
KEY POINTS Late Na(+) current (INaL) contributes to action potential remodelling and Ca(2+)/Na(+) changes in heart failure. The molecular identity of INaL remains unclear. The contributions of different Na(+) channel isoforms, apart from the cardiac isoform, remain unknown. We discovered and characterized a substantial contribution of neuronal isoform Nav1.1 to INaL. This new component is physiologically relevant to the control of action potential shape and duration, as well as to cell Ca(2+) dynamics, especially in heart failure. ABSTRACT Late Na(+) current (INaL) contributes to action potential (AP) duration and Ca(2+) handling in cardiac cells. Augmented INaL was implicated in delayed repolarization and impaired Ca(2+) handling in heart failure (HF). We tested if Na(+) channel (Nav) neuronal isoforms contribute to INaL and Ca(2+) cycling defects in HF in 17 dogs in which HF was achieved via sequential coronary artery embolizations. Six normal dogs served as control. Transient Na(+) current (INaT ) and INaL in left ventricular cardiomyocytes (VCMs) were recorded by patch clamp while Ca(2+) dynamics was monitored using Fluo-4. Virally delivered short interfering RNA (siRNA) ensured Nav1.1 and Nav1.5 post-transcriptional silencing. The expression of six Navs was observed in failing VCMs as follows: Nav1.5 (57.3%) > Nav1.2 (15.3%) > Nav1.1 (11.6%) > Nav2.1 (10.7%) > Nav1.3 (4.6%) > Nav1.6 (0.5%). Failing VCMs showed up-regulation of Nav1.1 expression, but reduction of Nav1.6 mRNA. A similar Nav expression pattern was found in samples from human hearts with ischaemic HF. VCMs with silenced Nav1.5 exhibited residual INaT and INaL (∼30% of control) with rightwardly shifted steady-state activation and inactivation. These currents were tetrodotoxin sensitive but resistant to MTSEA, a specific Nav1.5 blocker. The amplitude of the tetrodotoxin-sensitive INaL was 0.1709 ± 0.0299 pA pF(-1) (n = 7 cells) and the decay time constant was τ = 790 ± 76 ms (n = 5). This INaL component was lacking in VCMs with a silenced Nav1.1 gene, indicating that, among neuronal isoforms, Nav1.1 provides the largest contribution to INaL. At -10 mV this contribution is ∼60% of total INaL. Our further experimental and in silico examinations showed that this new Nav1.1 INaL component contributes to Ca(2+) accumulation in failing VCMs and modulates AP shape and duration. In conclusion, we have discovered an Nav1.1-originated INaL component in dog heart ventricular cells. This component is physiologically relevant to controlling AP shape and duration, as well as to cell Ca(2+) dynamics.
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Affiliation(s)
- Sudhish Mishra
- Department of Internal Medicine, Henry Ford Hospital, Detroit, MI, USA
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26
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Abstract
Mutations of the cardiac sodium channel (Nav1.5) can induce gain or loss of channel function. Gain-of-function mutations can cause long QT syndrome type 3 and possibly atrial fibrillation, whereas loss-of-function mutations are associated with a variety of phenotypes, such as Brugada syndrome, cardiac conduction disease, sick sinus syndrome, and possibly dilated cardiomyopathy. The phenotypes produced by Nav1.5 mutations vary according to the direct effect of the mutation on channel biophysics, but also with age, sex, body temperature, and between regions of the heart. This phenotypic variability makes genotype-phenotype correlations difficult. In this Perspectives article, we propose that phenotypic variability not ascribed to mutation-dependent changes in channel function might be the result of additional modifiers of channel behaviour, such as other genetic variation and alterations in transcription, RNA processing, translation, post-translational modifications, and protein degradation. Consideration of these modifiers might help to improve genotype-phenotype correlations and lead to new therapeutic strategies.
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Affiliation(s)
- Man Liu
- Warren Alpert Medical School, Brown University, 593 Eddy Street, APC730, Providence, RI 02903, USA
| | - Kai-Chien Yang
- Warren Alpert Medical School, Brown University, 593 Eddy Street, APC730, Providence, RI 02903, USA
| | - Samuel C Dudley
- Warren Alpert Medical School, Brown University, 593 Eddy Street, APC730, Providence, RI 02903, USA
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27
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Abstract
Late I Na is an integral part of the sodium current, which persists long after the fast-inactivating component. The magnitude of the late I Na is relatively small in all species and in all types of cardiomyocytes as compared with the amplitude of the fast sodium current, but it contributes significantly to the shape and duration of the action potential. This late component had been shown to increase in several acquired or congenital conditions, including hypoxia, oxidative stress, and heart failure, or due to mutations in SCN5A, which encodes the α-subunit of the sodium channel, as well as in channel-interacting proteins, including multiple β subunits and anchoring proteins. Patients with enhanced late I Na exhibit the type-3 long QT syndrome (LQT3) characterized by high propensity for the life-threatening ventricular arrhythmias, such as Torsade de Pointes (TdP), as well as for atrial fibrillation. There are several distinct mechanisms of arrhythmogenesis due to abnormal late I Na, including abnormal automaticity, early and delayed after depolarization-induced triggered activity, and dramatic increase of ventricular dispersion of repolarization. Many local anesthetic and antiarrhythmic agents have a higher potency to block late I Na as compared with fast I Na. Several novel compounds, including ranolazine, GS-458967, and F15845, appear to be the most selective inhibitors of cardiac late I Na reported to date. Selective inhibition of late I Na is expected to be an effective strategy for correcting these acquired and congenital channelopathies.
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Differential gene expression of cardiac ion channels in human dilated cardiomyopathy. PLoS One 2013; 8:e79792. [PMID: 24339868 PMCID: PMC3855055 DOI: 10.1371/journal.pone.0079792] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 09/25/2013] [Indexed: 11/23/2022] Open
Abstract
Background Dilated cardiomyopathy (DCM) is characterized by idiopathic dilation and systolic contractile dysfunction of the cardiac chambers. The present work aimed to study the alterations in gene expression of ion channels involved in cardiomyocyte function. Methods and Results Microarray profiling using the Affymetrix Human Gene® 1.0 ST array was performed using 17 RNA samples, 12 from DCM patients undergoing cardiac transplantation and 5 control donors (CNT). The analysis focused on 7 cardiac ion channel genes, since this category has not been previously studied in human DCM. SCN2B was upregulated, while KCNJ5, KCNJ8, CLIC2, CLCN3, CACNB2, and CACNA1C were downregulated. The RT-qPCR (21 DCM and 8 CNT samples) validated the gene expression of SCN2B (p < 0.0001), KCNJ5 (p < 0.05), KCNJ8 (p < 0.05), CLIC2 (p < 0.05), and CACNB2 (p < 0.05). Furthermore, we performed an IPA analysis and we found a functional relationship between the different ion channels studied in this work. Conclusion This study shows a differential expression of ion channel genes involved in cardiac contraction in DCM that might partly underlie the changes in left ventricular function observed in these patients. These results could be the basis for new genetic therapeutic approaches.
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29
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Partemi S, Batlle M, Berne P, Berruezo A, Campos B, Mont L, Riuró H, Roig E, Pérez-Villa F, Ortiz J, Pascali VL, Oliva A, Brugada R, Brugada J. Analysis of the arrhythmogenic substrate in human heart failure. Cardiovasc Pathol 2012; 22:133-40. [PMID: 23036686 DOI: 10.1016/j.carpath.2012.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 07/26/2012] [Accepted: 07/26/2012] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND The mechanism of sudden cardiac death in patients with heart failure (HF) is uncertain. Both electrical instability and structural remodelling could be factors that lead to fatal arrhythmias. We sought to analyse the expression of the sodium (SCN5A) and potassium (KCND3) channels as well as the fibrosis content in the ventricles of human HF and of non-diseased hearts under different post-mortem intervals. METHODS AND RESULTS We analysed normal human hearts as controls [n=20 for the right ventricle (RV) and n=13 for the left ventricle (LV)] and human hearts from HF patients, which were obtained at the time of cardiac transplantation, as cases (n=48 for RV and n=34 for LV). Transcription of the SCN5A (probes SCN5A E4-5, E11-12, and E28) and KCND3 channels and of COLLAGEN I and III were assayed by real-time polymerase chain reaction. In addition, paraffin sections were used to analyse the percentage of collagen deposition in both cases and controls. KCND3 mRNA expression in the LV was lower in the cases than in controls (P<.001). Higher levels of SCN5A mRNA were found in the HF samples when analysed with probe SCN5A E4-5 (P<.05). SCN5A expression was lower in the controls with longer post-mortem interval (n=4) than in the controls with a shorter post- mortem interval (n=16, P<.01). KCND3 mRNA levels were also different between the two control groups (P<.05). Collagen deposition was higher in the LV tissues of the cases when compared to controls (P<.001), and it was higher in the LV from HF patients than in the RV (P<.05). Furthermore, collagen deposition was higher in the LV samples from patients with implanted cardiac defibrillator (ICD) therapy than in the LV of patients with no ICD therapy (P<.05). CONCLUSIONS These data indicate that ionic and structural remodelling could be pathophysiological mechanisms of cardiac arrhythmias in HF patients.
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Affiliation(s)
- Sara Partemi
- Thorax Institute-Hospital Clínic, University of Barcelona (Cardiology Department) Institute of Biomedical Research August Pi iSunyer (IDIBAPS), Spain.
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Moreno JD, Clancy CE. Pathophysiology of the cardiac late Na current and its potential as a drug target. J Mol Cell Cardiol 2011; 52:608-19. [PMID: 22198344 DOI: 10.1016/j.yjmcc.2011.12.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/30/2011] [Accepted: 12/07/2011] [Indexed: 12/19/2022]
Abstract
A pathological increase in the late component of the cardiac Na(+) current, I(NaL), has been linked to disease manifestation in inherited and acquired cardiac diseases including the long QT variant 3 (LQT3) syndrome and heart failure. Disruption in I(NaL) leads to action potential prolongation, disruption of normal cellular repolarization, development of arrhythmia triggers, and propensity to ventricular arrhythmia. Attempts to treat arrhythmogenic sequelae from inherited and acquired syndromes pharmacologically with common Na(+) channel blockers (e.g. flecainide, lidocaine, and amiodarone) have been largely unsuccessful. This is due to drug toxicity and the failure of most current drugs to discriminate between the peak current component, chiefly responsible for single cell excitability and propagation in coupled tissue, and the late component (I(NaL)) of the Na(+) current. Although small in magnitude as compared to the peak Na(+) current (~1-3%), I(NaL) alters action potential properties and increases Na(+) loading in cardiac cells. With the increasing recognition that multiple cardiac pathological conditions share phenotypic manifestations of I(NaL) upregulation, there has been renewed interest in specific pharmacological inhibition of I(Na). The novel antianginal agent ranolazine, which shows a marked selectivity for late versus peak Na(+) current, may represent a novel drug archetype for targeted reduction of I(NaL). This article aims to review common pathophysiological mechanisms leading to enhanced I(NaL) in LQT3 and heart failure as prototypical disease conditions. Also reviewed are promising therapeutic strategies tailored to alter the molecular mechanisms underlying I(Na) mediated arrhythmia triggers.
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Affiliation(s)
- Jonathan D Moreno
- Tri-Institutional MD-PhD Program, Weill Cornell Medical College/The Rockefeller University/Sloan-Kettering Cancer Institute, New York, NY 10021, USA
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Johnson CM, Pogwizd SM. Focal initiation of sustained and nonsustained ventricular tachycardia in a canine model of ischemic cardiomyopathy. J Cardiovasc Electrophysiol 2011; 23:543-52. [PMID: 22175759 DOI: 10.1111/j.1540-8167.2011.02239.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION To define the role of focal and reentrant mechanisms underlying nonsustained (NSVT) and sustained ventricular tachycardia (SuVT) induced by programmed stimulation, 3-dimensional cardiac mapping was performed in 8 dogs with heart failure (HF) created by multiple intracoronary microsphere embolizations. METHODS AND RESULTS Continuous recording from 232 intramural sites throughout the left and right ventricles and the interventricular septum was performed during programmed stimulation in the absence and presence of isoproterenol (Iso, 0.1 μg/kg/min). Sinus beats and the last extrastimuli preceding induced VT conducted with total activation times (TA) of 51 ± 10 and 111 ± 8 milliseconds, respectively, that did not change during Iso infusion (47 ± 4 and 109 ± 5 milliseconds, P = NS). NSVT was induced in 75% of HF dogs; SuVT was induced in 38%. In all cases, initiation and maintenance of SuVT and NSVT arose by a focal mechanism. Compared to NSVT, SuVT had a shorter coupling interval (CI; 150 ± 7 vs 186 ± 16, P < 0.05) and a predilection for certain critical subendocardial initiation sites (that were initiation sites for only 29% of NSVT beats). After 21-30 beats, acceleration of SuVT by a focal mechanism to a CI less than 120 milliseconds led to functional conduction delay (TA increasing from 111 ± 3 to 137 ± 3 milliseconds, P < 0.0001), intramural reentry, and transition to ventricular fibrillation. CONCLUSIONS Thus, initiation of SuVT in a model of ischemic HF is due to a focal mechanism. However, subsequent acceleration of this focal mechanism can ultimately lead to functional conduction delay and development of intramural reentry.
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Affiliation(s)
- Carolyn M Johnson
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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Liu HB, Yang BF, Dong DL. Calcineurin and electrical remodeling in pathologic cardiac hypertrophy. Trends Cardiovasc Med 2011; 20:148-53. [PMID: 21742270 DOI: 10.1016/j.tcm.2010.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 12/13/2010] [Indexed: 10/18/2022]
Abstract
Calcineurin is a cytoplasmic Ca(2+)/calmodulin-dependent protein phosphatase that contributes to cardiac hypertrophy. Numerous studies have demonstrated that calcineurin/nuclear factor of activated T cell pathway affects the architecture of the heart under pathologic conditions, and the effects of calcineurin/nuclear factor of activated T cell pathway on cardiac hypertrophy have been well reviewed. Cardiac electrical remodeling is generally accompanied with the cardiac hypertrophy, and alteration of cardiac ion channel activity also leads to the changes of calcineurin activity and cardiac hypertrophy. Many studies have linked calcineurin with changes of a variety of ion channels, but the therapeutic approaches to target calcineurin for correcting cardiac electrical disturbance have not been formulated. Here, we review the recent progress in calcineurin and electrical remodeling in pathologic cardiac hypertrophy.
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Affiliation(s)
- Hui-Bin Liu
- Department of Pharmacology, Harbin Medical University, Harbin 150086, PR China
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Mishra S, Undrovinas NA, Maltsev VA, Reznikov V, Sabbah HN, Undrovinas A. Post-transcriptional silencing of SCN1B and SCN2B genes modulates late sodium current in cardiac myocytes from normal dogs and dogs with chronic heart failure. Am J Physiol Heart Circ Physiol 2011; 301:H1596-605. [PMID: 21705762 DOI: 10.1152/ajpheart.00948.2009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The emerging paradigm for Na(+) current in heart failure (HF) is that its transient component (I(NaT)) responsible for the action potential (AP) upstroke is decreased, whereas the late component (I(NaL)) involved in AP plateau is augmented. Here we tested whether Na(v)β(1)- and Na(v)β(2)-subunits can modulate I(NaL) parameters in normal and failing ventricular cardiomyocytes (VCMs). Chronic HF was produced in nine dogs by multiple sequential coronary artery microembolizations, and six dogs served as a control. I(Na) and APs were measured by the whole cell and perforated patch-clamp in freshly isolated and cultured VCMs, respectively. I(NaL) was augmented with slower decay in HF VCMs compared with normal heart VCMs, and these properties remained unchanged within 5 days of culture. Post-transcriptional silencing SCN1B and SCN2B were achieved by virally delivered short interfering RNA (siRNA) specific to Na(v)β(1) and Na(v)β(2). The delivery and efficiency of siRNA were evaluated by green fluorescent protein expression, by the real-time RT-PCR, and Western blots, respectively. Five days after infection, the levels of mRNA and protein for Na(v)β(1) and Na(v)β(2) were reduced by >80%, but mRNA and protein of Na(v)1.5, as well as I(NaT), remained unchanged in HF VCMs. Na(v)β(1)-siRNA reduced I(NaL) density and accelerated I(NaL) two-exponential decay, whereas Na(v)β(2)-siRNA produced an opposite effect in VCMs from both normal and failing hearts. Physiological importance of the discovered I(NaL) modulation to affect AP shape and duration was illustrated both experimentally and by numerical simulations of a VCM excitation-contraction coupling model. We conclude that in myocytes of normal and failing dog hearts Na(v)β(1) and Na(v)β(2) exhibit oppositely directed modulation of I(NaL).
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Affiliation(s)
- Sudhish Mishra
- Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan 48202-2689, USA
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Undrovinas NA, Maltsev VA, Belardinelli L, Sabbah HN, Undrovinas A. Late sodium current contributes to diastolic cell Ca2+ accumulation in chronic heart failure. J Physiol Sci 2010; 60:245-57. [PMID: 20490740 PMCID: PMC2891122 DOI: 10.1007/s12576-010-0092-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 04/06/2010] [Indexed: 12/19/2022]
Abstract
We elucidate the role of late Na+ current (INaL) for diastolic intracellular Ca2+ (DCa) accumulation in chronic heart failure (HF). HF was induced in 19 dogs by multiple coronary artery microembolizations; 6 normal dogs served as control. Ca2+ transients were recorded in field-paced (0.25 or 1.5 Hz) fluo-4-loaded ventricular myocytes (VM). INaL and action potentials were recorded by patch-clamp. Failing VM, but not normal VM, exhibited (1) prolonged action potentials and Ca2+ transients at 0.25 Hz, (2) substantial DCa accumulation at 1.5 Hz, and (3) spontaneous Ca2+ releases, which occurred after 1.5 Hz stimulation trains in ~31% cases. Selective INaL blocker ranolazine (10 microM) or the prototypical Na+ channel blocker tetrodotoxin (2 microM) reversibly improved function of failing VM. The DCa accumulation and the beneficial effect of INaL blockade were reproduced in silico using an excitation-contraction coupling model. We conclude that INaL contributes to diastolic Ca2+ accumulation and spontaneous Ca2+ release in HF.
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Affiliation(s)
| | - Victor A. Maltsev
- National Institute on Aging, Intramural Research Program, NIH, Baltimore, MD USA
| | | | - Hani N. Sabbah
- Department of Internal Medicine, Henry Ford Hospital, Detroit, MI USA
| | - Albertas Undrovinas
- Department of Internal Medicine, Henry Ford Hospital, Detroit, MI USA
- Cardiovascular Research, Henry Ford Hospital, Education and Research Bldg. Room 4015, 2799 West Grand Boulevard, Detroit, MI 48202-2689 USA
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Casini S, Tan HL, Demirayak I, Remme CA, Amin AS, Scicluna BP, Chatyan H, Ruijter JM, Bezzina CR, van Ginneken ACG, Veldkamp MW. Tubulin polymerization modifies cardiac sodium channel expression and gating. Cardiovasc Res 2009; 85:691-700. [PMID: 19861310 DOI: 10.1093/cvr/cvp352] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
AIMS Treatment with the anticancer drug taxol (TXL), which polymerizes the cytoskeleton protein tubulin, may evoke cardiac arrhythmias based on reduced human cardiac sodium channel (Na(v)1.5) function. Therefore, we investigated whether enhanced tubulin polymerization by TXL affects Na(v)1.5 function and expression and whether these effects are beta1-subunit-mediated. METHODS AND RESULTS Human embryonic kidney (HEK293) cells, transfected with SCN5A cDNA alone (Na(v)1.5) or together with SCN1B cDNA (Na(v)1.5 + beta1), and neonatal rat cardiomyocytes (NRCs) were incubated in the presence and in the absence of 100 microM TXL. Sodium current (I(Na)) characteristics were studied using patch-clamp techniques. Na(v)1.5 membrane expression was determined by immunocytochemistry and confocal microscopy. Pre-treatment with TXL reduced peak I(Na) amplitude nearly two-fold in both Na(v)1.5 and Na(v)1.5 + beta1, as well as in NRCs, compared with untreated cells. Accordingly, HEK293 cells and NRCs stained with anti-Na(v)1.5 antibody revealed a reduced membrane-labelling intensity in the TXL-treated groups. In addition, TXL accelerated I(Na) decay of Na(v)1.5 + beta1, whereas I(Na) decay of Na(v)1.5 remained unaltered. Finally, TXL reduced the fraction of channels that slow inactivated from 31% to 18%, and increased the time constant of slow inactivation by two-fold in Na(v)1.5. Conversely, slow inactivation properties of Na(v)1.5 + beta1 were unchanged by TXL. CONCLUSION Enhanced tubulin polymerization reduces sarcolemmal Na(v)1.5 expression and I(Na) amplitude in a beta1-subunit-independent fashion and causes I(Na) fast and slow inactivation impairment in a beta1-subunit-dependent way. These changes may underlie conduction-slowing-dependent cardiac arrhythmias under conditions of enhanced tubulin polymerization, e.g. TXL treatment and heart failure.
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Affiliation(s)
- Simona Casini
- Department of Clinical and Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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Xi Y, Wu G, Yang L, Han K, Du Y, Wang T, Lei X, Bai X, Ma A. Increased late sodium currents are related to transcription of neuronal isoforms in a pressure-overload model. Eur J Heart Fail 2009; 11:749-57. [PMID: 19584134 DOI: 10.1093/eurjhf/hfp092] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Yutao Xi
- Department of Cardiovascular Medicine; the First Affiliated Hospital of Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education; Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
| | - Geru Wu
- Department of Cardiovascular Medicine; the First Affiliated Hospital of Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education; Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
| | - Lin Yang
- Department of Cardiovascular Medicine; the First Affiliated Hospital of Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education; Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
| | - Ke Han
- Department of Cardiovascular Medicine; the First Affiliated Hospital of Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education; Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
| | - Yuan Du
- Department of Cardiovascular Medicine; the First Affiliated Hospital of Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education; Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
| | - Tingzhong Wang
- Department of Cardiovascular Medicine; the First Affiliated Hospital of Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education; Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
| | - Xinjun Lei
- Department of Cardiovascular Medicine; the First Affiliated Hospital of Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education; Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
| | - Xiaojun Bai
- Department of Cardiovascular Medicine; the First Affiliated Hospital of Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education; Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
| | - Aiqun Ma
- Department of Cardiovascular Medicine; the First Affiliated Hospital of Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
- Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education; Xi'an Jiaotong University; 277 West Yanta Road Xi'an Shaanxi 710061 China
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Maltsev VA, Kyle JW, Undrovinas A. Late Na+ current produced by human cardiac Na+ channel isoform Nav1.5 is modulated by its beta1 subunit. J Physiol Sci 2009; 59:217-25. [PMID: 19340536 PMCID: PMC2744134 DOI: 10.1007/s12576-009-0029-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Accepted: 02/02/2009] [Indexed: 01/26/2023]
Abstract
Experimental data accumulated over the past decade show the emerging importance of the late sodium current (I(NaL)) for the function of both normal and, especially, failing myocardium, in which I(NaL) is reportedly increased. While recent molecular studies identified the cardiac Na(+) channel (NaCh) alpha subunit isoform (Na(v)1.5) as a major contributor to I (NaL), the molecular mechanisms underlying alterations of I(NaL) in heart failure (HF) are still unknown. Here we tested the hypothesis that I(NaL) is modulated by the NaCh auxiliary beta subunits. tsA201 cells were transfected simultaneously with human Na(v)1.5 (former hH1a) and cardiac beta(1) or beta(2) subunits, and whole-cell patch-clamp experiments were performed. We found that I(NaL) decay kinetics were significantly slower in cells expressing alpha + beta(1) (time constant tau = 0.73 +/- 0.16 s, n = 14, mean +/- SEM, P < 0.05) but remained unchanged in cells expressing alpha + beta(2) (tau = 0.52 +/- 0.09 s, n = 5), compared with cells expressing Na(v)1.5 alone (tau = 0.54 +/- 0.09 s, n = 20). Also, beta(1), but not beta(2), dramatically increased I(NaL) relative to the maximum peak current, I(NaT) (2.3 +/- 0.48%, n = 14 vs. 0.48 +/- 0.07%, n = 6, P < 0.05, respectively) and produced a rightward shift of the steady-state availability curve. We conclude that the auxiliary beta(1) subunit modulates I(NaL), produced by the human cardiac Na(+) channel Na(v)1.5 by slowing its decay and increasing I(NaL) amplitude relative to I(NaT). Because expression of Na(v)1.5 reportedly decreases but beta(1) remains unchanged in chronic HF, the relatively higher expression of beta(1) may contribute to the known I(NaL) increase in HF via the modulation mechanism found in this study.
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Affiliation(s)
- Victor A. Maltsev
- Department of Internal Medicine, Cardiovascular Research, Henry Ford Hospital Detroit, Education and Research Bldg. Room 4015, 2799 West Grand Boulevard, Detroit, MI 48202-2689 USA
- Present Address: Gerontology Research Center, National Institute on Aging, NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224-6825 USA
| | - John W. Kyle
- Department of Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, IL USA
| | - Albertas Undrovinas
- Department of Internal Medicine, Cardiovascular Research, Henry Ford Hospital Detroit, Education and Research Bldg. Room 4015, 2799 West Grand Boulevard, Detroit, MI 48202-2689 USA
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Casini S, Verkerk AO, van Borren MMGJ, van Ginneken ACG, Veldkamp MW, de Bakker JMT, Tan HL. Intracellular calcium modulation of voltage-gated sodium channels in ventricular myocytes. Cardiovasc Res 2008; 81:72-81. [PMID: 18829699 DOI: 10.1093/cvr/cvn274] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Cardiac voltage-gated sodium channels control action potential (AP) upstroke and cell excitability. Intracellular calcium (Ca(i)(2+)) regulates AP properties by modulating various ion channels. Whether Ca(i)(2+) modulates sodium channels in ventricular myocytes is unresolved. We studied whether Ca(i)(2+) modulates sodium channels in ventricular myocytes at Ca(i)(2+) concentrations ([Ca(i)(2+)]) present during the cardiac AP (0-500 nM), and how this modulation affects sodium channel properties in heart failure (HF), a condition in which Ca(i)(2+) homeostasis is disturbed. METHODS AND RESULTS Sodium current (I(Na)) and maximal AP upstroke velocity (dV/dt(max)), a measure of I(Na), were studied at 20 and 37 degrees C, respectively, in freshly isolated left ventricular myocytes of control and HF rabbits, using whole-cell patch-clamp methodology. [Ca(i)(2+)] was varied using different pipette solutions, the Ca(i)(2+) buffer BAPTA, and caffeine administration. Elevated [Ca(i)(2+)] reduced I(Na) density and dV/dt(max), but caused no I(Na) gating changes. Reductions in I(Na) density occurred simultaneously with increase in [Ca(i)(2+)], suggesting that these effects were due to permeation block. Accordingly, unitary sodium current amplitudes were reduced at higher [Ca(i)(2+)]. While I(Na) density and gating at fixed [Ca(i)(2+)] were not different between HF and control, reductions in dV/dt(max) upon increases in stimulation rate were larger in HF than in control; these differences were abolished by BAPTA. CONCLUSION Ca(i)(2+) exerts acute modulation of I(Na) density in ventricular myocytes, but does not modify I(Na) gating. These effects, occurring rapidly and in the [Ca(i)(2+)] range observed physiologically, may contribute to beat-to-beat regulation of cardiac excitability in health and disease.
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Affiliation(s)
- Simona Casini
- Department of Clinical and Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Meibergdreef 9, AZ 1105 Amsterdam, The Netherlands
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Undrovinas A, Maltsev VA. Late sodium current is a new therapeutic target to improve contractility and rhythm in failing heart. Cardiovasc Hematol Agents Med Chem 2008; 6:348-59. [PMID: 18855648 PMCID: PMC2575131 DOI: 10.2174/187152508785909447] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Most cardiac Na+ channels open transiently within milliseconds upon membrane depolarization and are responsible for the excitation propagation. However, some channels remain active during hundreds of milliseconds, carrying the so-called persistent or late Na+ current (I(NaL)) throughout the action potential plateau. I(NaL) is produced by special gating modes of the cardiac-specific Na+ channel isoform. Experimental data accumulated over the past decade show the emerging importance of this late current component for the function of both normal and especially failing myocardium, where I(NaL) is reportedly increased. Na+ channels represent a multi-protein complex and its activity is determined not only by the pore-forming alpha subunit but also by its auxiliary beta subunits, cytoskeleton, and by Ca2+ signaling and trafficking proteins. Remodeling of this protein complex and intracellular signaling pathways may lead to alterations of I(NaL) in pathological conditions. Increased I(NaL) and the corresponding Na+ influx in failing myocardium contribute to abnormal repolarization and an increased cell Ca2+ load. Interventions designed to correct I(NaL) rescue normal repolarization and improve Ca2+ handling and contractility of the failing cardiomyocytes. New therapeutic strategies to target both arrhythmias and deficient contractility in HF may not be limited to the selective inhibition of I(NaL) but also include multiple indirect, modulatory (e.g. Ca(2+)- or cytoskeleton- dependent) mechanisms of I(NaL) function.
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Affiliation(s)
- Albertas Undrovinas
- Department of Internal Medicine, Henry Ford Hospital, Detroit, MI 48202-2689, USA.
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Maltsev VA, Kyle JW, Mishra S, Undrovinas A. Molecular identity of the late sodium current in adult dog cardiomyocytes identified by Nav1.5 antisense inhibition. Am J Physiol Heart Circ Physiol 2008; 295:H667-76. [PMID: 18552167 DOI: 10.1152/ajpheart.00111.2008] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Late Na(+) current (I(NaL)) is a major component of the action potential plateau in human and canine myocardium. Since I(NaL) is increased in heart failure and ischemia, it represents a novel potential target for cardioprotection. However, the molecular identity of I(NaL) remains unclear. We tested the hypothesis that the cardiac Na(+) channel isoform (Na(v)1.5) is a major contributor to I(NaL) in adult dog ventricular cardiomyocytes (VCs). Cultured VCs were exposed to an antisense morpholino-based oligonucleotide (Na(v)1.5 asOligo) targeting the region around the start codon of Na(v)1.5 mRNA or a control nonsense oligonucleotide (nsOligo). Densities of both transient Na(+) current (I(NaT)) and I(NaL) (both in pA/pF) were monitored by whole cell patch clamp. In HEK293 cells expressing Na(v)1.5 or Na(v)1.2, Na(v)1.5 asOligo specifically silenced functional expression of Na(v)1.5 (up to 60% of the initial I(NaT)) but not Na(v)1.2. In both nsOligo-treated controls and untreated VCs, I(NaT) and I(NaL) remained unchanged for up to 5 days. However, both I(NaT) and I(NaL) decreased exponentially with similar time courses (tau = 46 and 56 h, respectively) after VCs were treated with Na(v)1.5 asOligo without changes in 1) decay kinetics, 2) steady-state activation and inactivation, and 3) the ratio of I(NaL) to I(NaT). Four days after exposure to Na(v)1.5 asOligo, I(NaT) and I(NaL) amounted to 68 +/- 6% (mean +/- SE; n = 20, P < 0.01) and 60 +/- 7% (n = 11, P < 0.018) of those in VCs treated by nsOligo, respectively. We conclude that in adult dog heart Na(v)1.5 sodium channels have a "functional half-life" of approximately 35 h (0.69tau) and make a major contribution to I(NaL).
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Affiliation(s)
- Victor A Maltsev
- Department of Internal Medicine, Henry Ford Hospital, Cardiovascular Research, Education & Research Bldg. Rm. 4015, 2799 West Grand Blvd., Detroit, MI 48202-2689, USA
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Maltsev VA, Reznikov V, Undrovinas NA, Sabbah HN, Undrovinas A. Modulation of late sodium current by Ca2+, calmodulin, and CaMKII in normal and failing dog cardiomyocytes: similarities and differences. Am J Physiol Heart Circ Physiol 2008; 294:H1597-608. [PMID: 18203851 PMCID: PMC2376056 DOI: 10.1152/ajpheart.00484.2007] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Augmented and slowed late Na(+) current (I(NaL)) is implicated in action potential duration variability, early afterdepolarizations, and abnormal Ca(2+) handling in human and canine failing myocardium. Our objective was to study I(NaL) modulation by cytosolic Ca(2+) concentration ([Ca(2+)](i)) in normal and failing ventricular myocytes. Chronic heart failure was produced in 10 dogs by multiple sequential coronary artery microembolizations; 6 normal dogs served as a control. I(NaL) fine structure was measured by whole cell patch clamp in ventricular myocytes and approximated by a sum of fast and slow exponentials produced by burst and late scattered modes of Na(+) channel gating, respectively. I(NaL) greatly enhanced as [Ca(2+)](i) increased from "Ca(2+) free" to 1 microM: its maximum density increased, decay of both exponentials slowed, and the steady-state inactivation (SSI) curve shifted toward more positive potentials. Testing the inhibition of CaMKII and CaM revealed similarities and differences of I(NaL) modulation in failing vs. normal myocytes. Similarities include the following: 1) CaMKII slows I(NaL) decay and decreases the amplitude of fast exponentials, and 2) Ca(2+) shifts SSI rightward. Differences include the following: 1) slowing of I(NaL) by CaMKII is greater, 2) CaM shifts SSI leftward, and 3) Ca(2+) increases the amplitude of slow exponentials. We conclude that Ca(2+)/CaM/CaMKII signaling increases I(NaL) and Na(+) influx in both normal and failing myocytes by slowing inactivation kinetics and shifting SSI. This Na(+) influx provides a novel Ca(2+) positive feedback mechanism (via Na(+)/Ca(2+) exchanger), enhancing contractions at higher beating rates but worsening cardiomyocyte contractile and electrical performance in conditions of poor Ca(2+) handling in heart failure.
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Affiliation(s)
- Victor A Maltsev
- Henry Ford Hosp., Cardiovascular Research, Education & Research, Detroit, MI 48202-2689, USA
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Wu L, Yong SL, Fan C, Ni Y, Yoo S, Zhang T, Zhang X, Obejero-Paz CA, Rho HJ, Ke T, Szafranski P, Jones SW, Chen Q, Wang QK. Identification of a New Co-factor, MOG1, Required for the Full Function of Cardiac Sodium Channel Nav1.5. J Biol Chem 2008; 283:6968-78. [DOI: 10.1074/jbc.m709721200] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Maltsev VA, Undrovinas A. Late sodium current in failing heart: friend or foe? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2008; 96:421-51. [PMID: 17854868 PMCID: PMC2267741 DOI: 10.1016/j.pbiomolbio.2007.07.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Most cardiac Na+ channels open transiently upon membrane depolarization and then are quickly inactivated. However, some channels remain active, carrying the so-called persistent or late Na+ current (INaL) throughout the action potential (AP) plateau. Experimental data and the results of numerical modeling accumulated over the past decade show the emerging importance of this late current component for the function of both normal and failing myocardium. INaL is produced by special gating modes of the cardiac-specific Na+ channel isoform. Heart failure (HF) slows channel gating and increases INaL, but HF-specific Na+ channel isoform underlying these changes has not been found. Na+ channels represent a multi-protein complex and its activity is determined not only by the pore-forming alpha subunit but also by its auxiliary beta subunits, cytoskeleton, calmodulin, regulatory kinases and phosphatases, and trafficking proteins. Disruption of the integrity of this protein complex may lead to alterations of INaL in pathological conditions. Increased INaL and the corresponding Na+ flux in failing myocardium contribute to abnormal repolarization and an increased cell Ca2+ load. Interventions designed to correct INaL rescue normal repolarization and improve Ca2+ handling and contractility of the failing cardiomyocytes. This review considers (1) quantitative integration of INaL into the established electrophysiological and Ca2+ regulatory mechanisms in normal and failing cardiomyocytes and (2) a new therapeutic strategy utilizing a selective inhibition of INaL to target both arrhythmias and impaired contractility in HF.
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Affiliation(s)
- Victor A Maltsev
- Gerontology Research Center, National Institute on Aging, NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
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Electrocardiographic manifestation of anatomical substrates underlying post–myocardial infarction tachycardias. J Electrocardiol 2007; 40:S21-5. [DOI: 10.1016/j.jelectrocard.2007.05.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Accepted: 05/30/2007] [Indexed: 11/17/2022]
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Lopez-Santiago LF, Meadows LS, Ernst SJ, Chen C, Malhotra JD, McEwen DP, Speelman A, Noebels JL, Maier SK, Lopatin AN, Isom LL. Sodium channel Scn1b null mice exhibit prolonged QT and RR intervals. J Mol Cell Cardiol 2007; 43:636-47. [PMID: 17884088 PMCID: PMC2099572 DOI: 10.1016/j.yjmcc.2007.07.062] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 07/19/2007] [Accepted: 07/31/2007] [Indexed: 11/20/2022]
Abstract
In neurons, voltage-gated sodium channel beta subunits regulate the expression levels, subcellular localization, and electrophysiological properties of sodium channel alpha subunits. However, the contribution of beta subunits to sodium channel function in heart is poorly understood. We examined the role of beta1 in cardiac excitability using Scn1b null mice. Compared to wildtype mice, electrocardiograms recorded from Scn1b null mice displayed longer RR intervals and extended QT(c) intervals, both before and after autonomic block. In acutely dissociated ventricular myocytes, loss of beta1 expression resulted in a approximately 1.6-fold increase in both peak and persistent sodium current while channel gating and kinetics were unaffected. Na(v)1.5 expression increased in null myocytes approximately 1.3-fold. Action potential recordings in acutely dissociated ventricular myocytes showed slowed repolarization, supporting the extended QT(c) interval. Immunostaining of individual myocytes or ventricular sections revealed no discernable alterations in the localization of sodium channel alpha or beta subunits, ankyrin(B), ankyrin(G), N-cadherin, or connexin-43. Together, these results suggest that beta1 is critical for normal cardiac excitability and loss of beta1 may be associated with a long QT phenotype.
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Affiliation(s)
| | | | - Sara J. Ernst
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Chunling Chen
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
| | - Jyoti Dhar Malhotra
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Dyke P. McEwen
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
| | - Audrey Speelman
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
| | - Jeffrey L. Noebels
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | | | - Anatoli N. Lopatin
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109
| | - Lori L. Isom
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
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Wu L, Archacki SR, Zhang T, Wang QK. Induction of high STAT1 expression in transgenic mice with LQTS and heart failure. Biochem Biophys Res Commun 2007; 358:449-54. [PMID: 17490620 PMCID: PMC3505674 DOI: 10.1016/j.bbrc.2007.04.119] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 04/19/2007] [Indexed: 10/23/2022]
Abstract
Cardiac-specific expression of the N1325S mutation of SCN5A in transgenic mouse hearts (TG-NS) resulted in long QT syndrome (LQTS), ventricular arrhythmias (VT), and heart failure. In this study we carried out oligonucleotide mircoarray analysis to identify genes that are differentially expressed in the TG-NS mouse hearts. We identified 33 genes in five different functional groups that showed differential expression. None of the 33 genes are ion channel genes. STAT1, which encodes a transcription factor involved in apoptosis and interferon response, showed the most significant difference of expression between TG-NS and control mice (a nearly 10-fold increase in expression, P=4x10(-6)). The results were further confirmed by quantitative real-time PCR and Western blot analyses. Accordingly, many interferon response genes also showed differential expression in TG-NS hearts. This study represents the first microarray analysis for LQTS and implicates STAT1 in the pathogenesis and progression of LQTS and heart failure.
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Affiliation(s)
- Ling Wu
- Center for Cardiovascular Genetics and Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115
| | - Stephen R. Archacki
- Center for Cardiovascular Genetics and Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115
| | - Teng Zhang
- Center for Cardiovascular Genetics and Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, 44195
| | - Qing K. Wang
- Center for Cardiovascular Genetics and Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, 44195
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan, P. R. China
- Corresponding author. Address: Center for Cardiovascular Genetics/NE4-202, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave., Cleveland, OH 44195, USA. Fax: +1 216 636 1231
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Silva GJJ, Pereira AC, Krieger EM, Krieger JE. Genetic mapping of a new heart rate QTL on chromosome 8 of spontaneously hypertensive rats. BMC MEDICAL GENETICS 2007; 8:17. [PMID: 17419875 PMCID: PMC1865373 DOI: 10.1186/1471-2350-8-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Accepted: 04/09/2007] [Indexed: 01/19/2023]
Abstract
Background Tachycardia is commonly observed in hypertensive patients, predominantly mediated by regulatory mechanisms integrated within the autonomic nervous system. The genetic loci and genes associated with increased heart rate in hypertension, however, have not yet been identified. Methods An F2 intercross of Spontaneously Hypertensive Rats (SHR) × Brown Norway (BN) linkage analysis of quantitative trait loci mapping was utilized to identify candidate genes associated with an increased heart rate in arterial hypertension. Results Basal heart rate in SHR was higher compared to that of normotensive BN rats (365 ± 3 vs. 314 ± 6 bpm, p < 0.05 for SHR and BN, respectively). A total genome scan identified one quantitative trait locus in a 6.78 cM interval on rat chromosome 8 (8q22–q24) that was responsible for elevated heart rate. This interval contained 241 genes, of which 65 are known genes. Conclusion Our data suggest that an influential genetic region located on the rat chromosome 8 contributes to the regulation of heart rate. Candidate genes that have previously been associated with tachycardia and/or hypertension were found within this QTL, strengthening our hypothesis that these genes are, potentially, associated with the increase in heart rate in a hypertension rat model.
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Affiliation(s)
- Gustavo JJ Silva
- Department of Medicine-LIM13, Heart Institute (InCor), University of São Paulo Medical School, Av. Dr. Enéas de Carvalho Aguiar, 44, 10o andar, 05403-000, São Paulo, SP, Brazil
| | - Alexandre C Pereira
- Department of Medicine-LIM13, Heart Institute (InCor), University of São Paulo Medical School, Av. Dr. Enéas de Carvalho Aguiar, 44, 10o andar, 05403-000, São Paulo, SP, Brazil
| | - Eduardo M Krieger
- Department of Medicine-LIM13, Heart Institute (InCor), University of São Paulo Medical School, Av. Dr. Enéas de Carvalho Aguiar, 44, 10o andar, 05403-000, São Paulo, SP, Brazil
| | - José E Krieger
- Department of Medicine-LIM13, Heart Institute (InCor), University of São Paulo Medical School, Av. Dr. Enéas de Carvalho Aguiar, 44, 10o andar, 05403-000, São Paulo, SP, Brazil
- Laboratório de Genética e Cardiologia Molecular, Instituto do Coração (InCor) da Faculdade de Medicina da Universidade de São Paulo, Brazil, Av. Dr. Enéas de Carvalho Aguiar, 44 São Paulo, Brazil
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Nattel S, Maguy A, Le Bouter S, Yeh YH. Arrhythmogenic Ion-Channel Remodeling in the Heart: Heart Failure, Myocardial Infarction, and Atrial Fibrillation. Physiol Rev 2007; 87:425-56. [PMID: 17429037 DOI: 10.1152/physrev.00014.2006] [Citation(s) in RCA: 597] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Rhythmic and effective cardiac contraction depends on appropriately timed generation and spread of cardiac electrical activity. The basic cellular unit of such activity is the action potential, which is shaped by specialized proteins (channels and transporters) that control the movement of ions across cardiac cell membranes in a highly regulated fashion. Cardiac disease modifies the operation of ion channels and transporters in a way that promotes the occurrence of cardiac rhythm disturbances, a process called “arrhythmogenic remodeling.” Arrhythmogenic remodeling involves alterations in ion channel and transporter expression, regulation and association with important protein partners, and has important pathophysiological implications that contribute in major ways to cardiac morbidity and mortality. We review the changes in ion channel and transporter properties associated with three important clinical and experimental paradigms: congestive heart failure, myocardial infarction, and atrial fibrillation. We pay particular attention to K+, Na+, and Ca2+channels; Ca2+transporters; connexins; and hyperpolarization-activated nonselective cation channels and discuss the mechanisms through which changes in ion handling processes lead to cardiac arrhythmias. We highlight areas of future investigation, as well as important opportunities for improved therapeutic approaches that are being opened by an improved understanding of the mechanisms of arrhythmogenic remodeling.
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Affiliation(s)
- Stanley Nattel
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Quebec, Canada.
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Liu XS, Jiang M, Zhang M, Tang D, Clemo HF, Higgins RSD, Tseng GN. Electrical remodeling in a canine model of ischemic cardiomyopathy. Am J Physiol Heart Circ Physiol 2007; 292:H560-71. [PMID: 16920806 DOI: 10.1152/ajpheart.00616.2006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The nature of electrical remodeling in a canine model of ischemic cardiomyopathy (ICM; induced by repetitive intracoronary microembolizations) that exhibits spontaneous ventricular tachycardia is not entirely clear. We used the patch-clamp technique to record action potentials and ionic currents of left ventricular myocytes isolated from the region affected by microembolizations. We also used the immunoblot technique to examine channel subunit expression in adjacent affected tissue. Ventricular myocytes and tissue isolated from the corresponding region of normal hearts served as control. ICM myocytes had prolonged action potential duration (APD) and more pronounced APD dispersion. Slow delayed rectifier current ( IKs) was reduced at voltages positive to 0 mV, along with a negative shift in its voltage dependence of activation. Immunoblots showed that there was no change in KCNQ1.1 ( IKs pore-forming or α-subunit), but KCNE1 ( IKs auxiliary or β-subunit) was reduced, and KCNQ1.2 (a truncated KCNQ1 splice variant with a dominant-negative effect on IKs) was increased. Transient outward current ( Ito) was reduced, along with an acceleration of the slow phase of recovery from inactivation. Immunoblots showed that there was no change in Kv4.3 (α-subunit of fast-recovering Ito component), but KChIP2 (β-subunit of fast-recovering component) and Kv1.4 (α-subunit of slow-recovering component) were reduced. Inward rectifier current was reduced. L-type Ca current was unaltered. The immunoblot data provide mechanistic insights into the observed changes in current amplitude and gating kinetics of IKs and Ito. We suggest that these changes, along with the decrease in inward rectifier current, contribute to APD prolongation in ICM hearts.
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Affiliation(s)
- Xian-Sheng Liu
- Dept. of Physiology, Virginia Commonwealth Univ., Richmond, VA 23298, USA
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Undrovinas AI, Belardinelli L, Undrovinas NA, Sabbah HN. Ranolazine improves abnormal repolarization and contraction in left ventricular myocytes of dogs with heart failure by inhibiting late sodium current. J Cardiovasc Electrophysiol 2006; 17 Suppl 1:S169-S177. [PMID: 16686675 PMCID: PMC1482456 DOI: 10.1111/j.1540-8167.2006.00401.x] [Citation(s) in RCA: 195] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Ventricular repolarization and contractile function are frequently abnormal in ventricular myocytes from human failing hearts as well as canine hearts with experimentally induced heart failure (HF). These abnormalities have been attributed to dysfunction involving various steps of the excitation-contraction coupling process, leading to impaired intracellular sodium and calcium homeostasis. We previously reported that the slow inactivating component of the Na(+) current (late I(Na)) is augmented in myocytes from failing hearts, and this appears to play a significant role in abnormal ventricular myocytes repolarization and function. We tested the effect of ranolazine, a novel drug being developed to treat angina, on (1) action potential duration (APD), (2) peak transient and late I(Na) (I(NaT) and I(NaL), respectively), (3) early afterdepolarizations (EADs), and (4) twitch contraction (TC), including after contractions and contracture. METHODS Myocytes were isolated from the left ventricle of normal dogs and of dogs with chronic HF caused by multiple sequential intracoronary micro-embolizations. I(NaT) and I(NaL) were recorded using conventional whole-cell patch-clamp techniques. APs were recorded using the beta-escin perforated patch-clamp configuration at frequencies of 0.25 and 0.5 Hz. TCs were recorded using an edge movement detector at stimulation frequencies ranging from 0.5 to 2.0 Hz. RESULTS Ranolazine significantly (P<0.05) and reversibly shortened the APD of myocytes stimulated at either 0.5 or 0.25 Hz in a concentration-dependent manner. At a stimulation frequency of 0.5 Hz, 5, 10, and 20 microM ranolazine shortened the APD(90) (APD measured at 90% repolarization) from 516+/-51 to 304+/-22, 212+/-34 and 160+/-11 ms, respectively, and markedly decreased beat-to-beat variability of APD(90), EADs, and dispersion of APDs. Ranolazine preferentially blocked I(NaL) relative to I(NaT) in a state-dependent manner, with a approximately 38-fold greater potency against I(NaL) to produce tonic block (IC(50)=6.5 microM) than I(NaT) (IC(50)=294 microM). When we evaluated inactivated state blockade of I(NaL) from the steady-state inactivation mid-potential shift using a theoretical model, ranolazine was found to bind more tightly to the inactivated state than the resting state of the sodium channel underlying I(NaL), with apparent dissociation constants K(dr)=7.47 microM and K(di)=1.71 microM, respectively. TCs of myocytes stimulated at 0.5 Hz were characterized by an initial spike followed by a dome-like after contraction, which was observed in 75% of myocytes from failing hearts and coincided with the long AP plateau and EADs. Ranolazine at 5 and 10 microM reversibly shortened the duration of TCs and abolished the after contraction. When the rate of myocyte stimulation was increased from 1.0 to 2.0 Hz, there was a progressive increase in diastolic "tension," that is, contracture. Ranolazine at 5 and 10 microM reversibly prevented this frequency-dependent contracture.
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Affiliation(s)
- Albertas I Undrovinas
- Heart and Vascular Institute, Henry Ford Hospital, Detroit, Michigan 48202-2689, USA.
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