1
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Dries E, Gilbert G, Roderick HL, Sipido KR. The ryanodine receptor microdomain in cardiomyocytes. Cell Calcium 2023; 114:102769. [PMID: 37390591 DOI: 10.1016/j.ceca.2023.102769] [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: 05/02/2023] [Revised: 06/11/2023] [Accepted: 06/12/2023] [Indexed: 07/02/2023]
Abstract
The ryanodine receptor type 2 (RyR) is a key player in Ca2+ handling during excitation-contraction coupling. During each heartbeat, RyR channels are responsible for linking the action potential with the contractile machinery of the cardiomyocyte by releasing Ca2+ from the sarcoplasmic reticulum. RyR function is fine-tuned by associated signalling molecules, arrangement in clusters and subcellular localization. These parameters together define RyR function within microdomains and are subject to disease remodelling. This review describes the latest findings on RyR microdomain organization, the alterations with disease which result in increased subcellular heterogeneity and emergence of microdomains with enhanced arrhythmogenic potential, and presents novel technologies that guide future research to study and target RyR channels within specific microdomains.
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Affiliation(s)
- Eef Dries
- Lab of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium.
| | - Guillaume Gilbert
- Lab of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium; Laboratoire ORPHY EA 4324, Université de Brest, Brest, France
| | - H Llewelyn Roderick
- Lab of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
| | - Karin R Sipido
- Lab of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
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2
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Deb A, Tow BD, Qing Y, Walker M, Hodges ER, Stewart JA, Knollmann BC, Zheng Y, Wang Y, Liu B. Genetic Inhibition of Mitochondrial Permeability Transition Pore Exacerbates Ryanodine Receptor 2 Dysfunction in Arrhythmic Disease. Cells 2023; 12:204. [PMID: 36672139 PMCID: PMC9856515 DOI: 10.3390/cells12020204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/12/2022] [Accepted: 12/21/2022] [Indexed: 01/06/2023] Open
Abstract
The brief opening mode of the mitochondrial permeability transition pore (mPTP) serves as a calcium (Ca2+) release valve to prevent mitochondrial Ca2+ (mCa2+) overload. Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a stress-induced arrhythmic syndrome due to mutations in the Ca2+ release channel complex of ryanodine receptor 2 (RyR2). We hypothesize that inhibiting the mPTP opening in CPVT exacerbates the disease phenotype. By crossbreeding a CPVT model of CASQ2 knockout (KO) with a mouse missing CypD, an activator of mPTP, a double KO model (DKO) was generated. Echocardiography, cardiac histology, and live-cell imaging were employed to assess the severity of cardiac pathology. Western blot and RNAseq were performed to evaluate the contribution of various signaling pathways. Although exacerbated arrhythmias were reported, the DKO model did not exhibit pathological remodeling. Myocyte Ca2+ handling was similar to that of the CASQ2 KO mouse at a low pacing frequency. However, increased ROS production, activation of the CaMKII pathway, and hyperphosphorylation of RyR2 were detected in DKO. Transcriptome analysis identified altered gene expression profiles associated with electrical instability in DKO. Our study provides evidence that genetic inhibition of mPTP exacerbates RyR2 dysfunction in CPVT by increasing activation of the CaMKII pathway and subsequent hyperphosphorylation of RyR2.
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Affiliation(s)
- Arpita Deb
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Brian D. Tow
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - You Qing
- Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Bioinformatics Center, Beijing University of Agriculture, Beijing 102206, China
| | - Madelyn Walker
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Emmanuel R. Hodges
- School of Pharmacy, Division of BioMolecular Sciences, University of Mississippi, Oxford, MS 38677, USA
| | - James A. Stewart
- School of Pharmacy, Division of BioMolecular Sciences, University of Mississippi, Oxford, MS 38677, USA
| | - Björn C. Knollmann
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yi Zheng
- Beijing Key Laboratory for Agricultural Application and New Technique, College of Plant Science and Technology, Bioinformatics Center, Beijing University of Agriculture, Beijing 102206, China
| | - Ying Wang
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
| | - Bin Liu
- Department of Biological Sciences, Mississippi State University, Starkville, MS 39762, USA
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3
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Uddin ME, Eisenmann ED, Li Y, Huang KM, Garrison DA, Talebi Z, Gibson AA, Jin Y, Nepal M, Bonilla IM, Fu Q, Sun X, Millar A, Tarasov M, Jay CE, Cui X, Einolf HJ, Pelis RM, Smith SA, Radwański PB, Sweet DH, König J, Fromm MF, Carnes CA, Hu S, Sparreboom A. MATE1 Deficiency Exacerbates Dofetilide-Induced Proarrhythmia. Int J Mol Sci 2022; 23:8607. [PMID: 35955741 PMCID: PMC9369325 DOI: 10.3390/ijms23158607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 07/30/2022] [Accepted: 07/30/2022] [Indexed: 02/04/2023] Open
Abstract
Dofetilide is a rapid delayed rectifier potassium current inhibitor widely used to prevent the recurrence of atrial fibrillation and flutter. The clinical use of this drug is associated with increases in QTc interval, which predispose patients to ventricular cardiac arrhythmias. The mechanisms involved in the disposition of dofetilide, including its movement in and out of cardiomyocytes, remain unknown. Using a xenobiotic transporter screen, we identified MATE1 (SLC47A1) as a transporter of dofetilide and found that genetic knockout or pharmacological inhibition of MATE1 in mice was associated with enhanced retention of dofetilide in cardiomyocytes and increased QTc prolongation. The urinary excretion of dofetilide was also dependent on the MATE1 genotype, and we found that this transport mechanism provides a mechanistic basis for previously recorded drug-drug interactions of dofetilide with various contraindicated drugs, including bictegravir, cimetidine, ketoconazole, and verapamil. The translational significance of these observations was examined with a physiologically-based pharmacokinetic model that adequately predicted the drug-drug interaction liabilities in humans. These findings support the thesis that MATE1 serves a conserved cardioprotective role by restricting excessive cellular accumulation and warrant caution against the concurrent administration of potent MATE1 inhibitors and cardiotoxic substrates with a narrow therapeutic window.
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Affiliation(s)
- Muhammad Erfan Uddin
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Eric D. Eisenmann
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Yang Li
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Kevin M. Huang
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Dominique A. Garrison
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Zahra Talebi
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Alice A. Gibson
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Yan Jin
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Mahesh Nepal
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Ingrid M. Bonilla
- Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA;
| | - Qiang Fu
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Xinxin Sun
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
| | - Alec Millar
- Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (A.M.); (M.T.); (P.B.R.); (C.A.C.); (S.H.)
| | - Mikhail Tarasov
- Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (A.M.); (M.T.); (P.B.R.); (C.A.C.); (S.H.)
| | - Christopher E. Jay
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298, USA; (C.E.J.); (D.H.S.)
| | - Xiaoming Cui
- Novartis Institute for Biomedical Research, East Hanover, NJ 07936, USA; (X.C.); (H.J.E.); (R.M.P.)
| | - Heidi J. Einolf
- Novartis Institute for Biomedical Research, East Hanover, NJ 07936, USA; (X.C.); (H.J.E.); (R.M.P.)
| | - Ryan M. Pelis
- Novartis Institute for Biomedical Research, East Hanover, NJ 07936, USA; (X.C.); (H.J.E.); (R.M.P.)
| | - Sakima A. Smith
- OSU Wexner Medical Center, Department of Internal Medicine, Division of Cardiovascular Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Przemysław B. Radwański
- Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (A.M.); (M.T.); (P.B.R.); (C.A.C.); (S.H.)
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
| | - Douglas H. Sweet
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298, USA; (C.E.J.); (D.H.S.)
| | - Jörg König
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; (J.K.); (M.F.F.)
| | - Martin F. Fromm
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany; (J.K.); (M.F.F.)
| | - Cynthia A. Carnes
- Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (A.M.); (M.T.); (P.B.R.); (C.A.C.); (S.H.)
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
- Division of Pharmacy Practice and Science, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Shuiying Hu
- Division of Outcomes and Translational Sciences, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (A.M.); (M.T.); (P.B.R.); (C.A.C.); (S.H.)
| | - Alex Sparreboom
- Division of Pharmaceutics and Pharmacology, College of Pharmacy and Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, USA; (M.E.U.); (E.D.E.); (Y.L.); (K.M.H.); (D.A.G.); (Z.T.); (A.A.G.); (Y.J.); (M.N.); (Q.F.); (X.S.)
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4
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Baine S, Bonilla I, Belevych A, Stepanov A, Dorn LE, Terentyeva R, Terentyev D, Accornero F, Carnes CA, Gyorke S. Pyridostigmine improves cardiac function and rhythmicity through RyR2 stabilization and inhibition of STIM1-mediated calcium entry in heart failure. J Cell Mol Med 2021; 25:4637-4648. [PMID: 33755308 PMCID: PMC8107086 DOI: 10.1111/jcmm.16356] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 01/12/2021] [Accepted: 01/25/2021] [Indexed: 12/20/2022] Open
Abstract
Heart failure (HF) is characterized by asymmetrical autonomic balance. Treatments to restore parasympathetic activity in human heart failure trials have shown beneficial effects. However, mechanisms of parasympathetic-mediated improvement in cardiac function remain unclear. The present study examined the effects and underpinning mechanisms of chronic treatment with the cholinesterase inhibitor, pyridostigmine (PYR), in pressure overload HF induced by transverse aortic constriction (TAC) in mice. TAC mice exhibited characteristic adverse structural (left ventricular hypertrophy) and functional remodelling (reduced ejection fraction, altered myocyte calcium (Ca) handling, increased arrhythmogenesis) with enhanced predisposition to arrhythmogenic aberrant sarcoplasmic reticulum (SR) Ca release, cardiac ryanodine receptor (RyR2) hyper-phosphorylation and up-regulated store-operated Ca entry (SOCE). PYR treatment resulted in improved cardiac contractile performance and rhythmic activity relative to untreated TAC mice. Chronic PYR treatment inhibited altered intracellular Ca handling by alleviating aberrant Ca release and diminishing pathologically enhanced SOCE in TAC myocytes. At the molecular level, these PYR-induced changes in Ca handling were associated with reductions of pathologically enhanced phosphorylation of RyR2 serine-2814 and STIM1 expression in HF myocytes. These results suggest that chronic cholinergic augmentation alleviates HF via normalization of both canonical RyR2-mediated SR Ca release and non-canonical hypertrophic Ca signaling via STIM1-dependent SOCE.
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Affiliation(s)
- Stephen Baine
- College of Pharmacy, The Ohio State University, Columbus, OH, USA
| | - Ingrid Bonilla
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Andriy Belevych
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Andrei Stepanov
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Lisa E Dorn
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Radmila Terentyeva
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Dmitry Terentyev
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Federica Accornero
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Cynthia A Carnes
- College of Pharmacy, The Ohio State University, Columbus, OH, USA.,Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
| | - Sandor Gyorke
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, USA
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5
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Zhou X, Li A, Lin PH, Zhou J, Ma J. TRIC-A regulates intracellular Ca 2+ homeostasis in cardiomyocytes. Pflugers Arch 2021; 473:547-556. [PMID: 33474637 PMCID: PMC7940156 DOI: 10.1007/s00424-021-02513-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/14/2020] [Accepted: 01/04/2021] [Indexed: 01/26/2023]
Abstract
Trimeric intracellular cation (TRIC) channels have been identified as monovalent cation channels that are located in the ER/SR membrane. Two isoforms discovered in mammals are TRIC-A (TMEM38a) and TRIC-B (TMEM38b). TRIC-B ubiquitously expresses in all tissues, and TRIC-B-/- mice is lethal at the neonatal stage. TRIC-A mainly expresses in excitable cells. TRIC-A-/- mice survive normally but show abnormal SR Ca2+ handling in both skeletal and cardiac muscle cells. Importantly, TRIC-A mutations have been identified in human patients with stress-induced arrhythmia. In the past decade, important discoveries have been made to understand the structure and function of TRIC channels, especially its role in regulating intracellular Ca2+ homeostasis. In this review article, we focus on the potential roles of TRIC-A in regulating cardiac function, particularly its effects on intracellular Ca2+ signaling of cardiomyocytes and discuss the current knowledge gaps.
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Affiliation(s)
- Xinyu Zhou
- Department of Surgery, The Ohio State University Columbus, Columbus, OH, 43210, USA
| | - Ang Li
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, 76019, USA
| | - Pei-Hui Lin
- Department of Surgery, The Ohio State University Columbus, Columbus, OH, 43210, USA
| | - Jingsong Zhou
- Department of Kinesiology, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, 76019, USA
| | - Jianjie Ma
- Department of Surgery, The Ohio State University Columbus, Columbus, OH, 43210, USA.
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6
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Baine S, Thomas J, Bonilla I, Ivanova M, Belevych A, Li J, Veeraraghavan R, Radwanski PB, Carnes C, Gyorke S. Muscarinic-dependent phosphorylation of the cardiac ryanodine receptor by protein kinase G is mediated by PI3K-AKT-nNOS signaling. J Biol Chem 2020; 295:11720-11728. [PMID: 32580946 PMCID: PMC7450129 DOI: 10.1074/jbc.ra120.014054] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/20/2020] [Indexed: 12/30/2022] Open
Abstract
Post-translational modifications of proteins involved in calcium handling in myocytes, such as the cardiac ryanodine receptor (RyR2), critically regulate cardiac contractility. Recent studies have suggested that phosphorylation of RyR2 by protein kinase G (PKG) might contribute to the cardioprotective effects of cholinergic stimulation. However, the specific mechanisms underlying these effects remain unclear. Here, using murine ventricular myocytes, immunoblotting, proximity ligation as-says, and nitric oxide imaging, we report that phosphorylation of Ser-2808 in RyR2 induced by the muscarinic receptor agonist carbachol is mediated by a signaling axis comprising phosphoinositide 3-phosphate kinase, Akt Ser/Thr kinase, nitric oxide synthase 1, nitric oxide, soluble guanylate cyclase, cyclic GMP (cGMP), and PKG. We found that this signaling pathway is compartmentalized in myocytes, as it was distinct from atrial natriuretic peptide receptor-cGMP-PKG-RyR2 Ser-2808 signaling and independent of muscarinic-induced phosphorylation of Ser-239 in vasodilator-stimulated phosphoprotein. These results provide detailed insights into muscarinic-induced PKG signaling and the mediators that regulate cardiac RyR2 phosphorylation critical for cardiovascular function.
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Affiliation(s)
- Stephen Baine
- College of Pharmacy, Ohio State University, Columbus, Ohio, USA
| | - Justin Thomas
- College of Pharmacy, Ohio State University, Columbus, Ohio, USA
| | - Ingrid Bonilla
- Department of Physiology and Cell Biology, Ohio State University, Columbus, Ohio, USA
| | - Marina Ivanova
- Department of Physiology and Cell Biology, Ohio State University, Columbus, Ohio, USA
| | - Andriy Belevych
- Department of Physiology and Cell Biology, Ohio State University, Columbus, Ohio, USA
| | - Jiaoni Li
- Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA
| | | | | | - Cynthia Carnes
- College of Pharmacy, Ohio State University, Columbus, Ohio, USA
| | - Sandor Gyorke
- Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA
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7
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Hamilton S, Terentyeva R, Martin B, Perger F, Li J, Stepanov A, Bonilla IM, Knollmann BC, Radwański PB, Györke S, Belevych AE, Terentyev D. Increased RyR2 activity is exacerbated by calcium leak-induced mitochondrial ROS. Basic Res Cardiol 2020; 115:38. [PMID: 32444920 PMCID: PMC7244455 DOI: 10.1007/s00395-020-0797-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 05/07/2020] [Indexed: 11/29/2022]
Abstract
Cardiac disease is associated with deleterious emission of mitochondrial reactive oxygen species (mito-ROS), as well as enhanced oxidation and activity of the sarcoplasmic reticulum (SR) Ca2+ release channel, the ryanodine receptor (RyR2). The transfer of Ca2+ from the SR via RyR2 to mitochondria is thought to play a key role in matching increased metabolic demand during stress. In this study, we investigated whether augmented RyR2 activity results in self-imposed exacerbation of SR Ca2+ leak, via altered SR-mitochondrial Ca2+ transfer and elevated mito-ROS emission. Fluorescent indicators and spatially restricted genetic ROS probes revealed that both pharmacologically and genetically enhanced RyR2 activity, in ventricular myocytes from rats and catecholaminergic polymorphic ventricular tachycardia (CPVT) mice, respectively, resulted in increased ROS emission under β-adrenergic stimulation. Expression of mitochondrial Ca2+ probe mtRCamp1h revealed diminished net mitochondrial [Ca2+] with enhanced SR Ca2+ leak, accompanied by depolarization of the mitochondrial matrix. While this may serve as a protective mechanism to prevent mitochondrial Ca2+ overload, protection is not complete and enhanced mito-ROS emission resulted in oxidation of RyR2, further amplifying proarrhythmic SR Ca2+ release. Importantly, the effects of augmented RyR2 activity could be attenuated by mitochondrial ROS scavenging, and experiments with dominant-negative paralogs of the mitochondrial Ca2+ uniporter (MCU) supported the hypothesis that SR-mitochondria Ca2+ transfer is essential for the increase in mito-ROS. We conclude that in a process whereby leak begets leak, augmented RyR2 activity modulates mitochondrial Ca2+ handling, promoting mito-ROS emission and driving further channel activity in a proarrhythmic feedback cycle in the diseased heart.
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Affiliation(s)
- Shanna Hamilton
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Radmila Terentyeva
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Benjamin Martin
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Fruzsina Perger
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Jiaoni Li
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Andrei Stepanov
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Laboratory of Cell Pathology, Institute RAS, Saint Petersburg, Russia
| | - Ingrid M Bonilla
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Björn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University Medical School, Nashville, TN, 37232, USA
| | - Przemyslaw B Radwański
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Division of Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH, 43210, USA
| | - Sandor Györke
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Andriy E Belevych
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Dmitry Terentyev
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA. .,Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA.
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8
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Conditional Up-Regulation of SERCA2a Exacerbates RyR2-Dependent Ventricular and Atrial Arrhythmias. Int J Mol Sci 2020; 21:ijms21072535. [PMID: 32260593 PMCID: PMC7178036 DOI: 10.3390/ijms21072535] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 03/31/2020] [Accepted: 04/01/2020] [Indexed: 12/16/2022] Open
Abstract
Ryanodine receptor 2 (RyR2) and SERCA2a are two major players in myocyte calcium (Ca) cycling that are modulated physiologically, affected by disease and thus considered to be potential targets for cardiac disease therapy. However, how RyR2 and SERCA2a influence each others’ activities, as well as the primary and secondary consequences of their combined manipulations remain controversial. In this study, we examined the effect of acute upregulation of SERCA2a on arrhythmogenesis by conditionally overexpressing SERCA2a in a mouse model featuring hyperactive RyR2s due to ablation of calsequestrin 2 (CASQ2). CASQ2 knock-out (KO) mice were crossbred with doxycycline (DOX)-inducible SERCA2a transgenic mice to generate KO-TG mice. In-vivo ECG studies have shown that induction of SERCA2a (DOX+) overexpression markedly exacerbated both ventricular and atrial arrhythmias in vivo, compared with uninduced KO-TG mice (DOX-). Consistent with that, confocal microscopy in both atrial and ventricular myocytes demonstrated that conditional upregulation of SERCA2a enhanced the rate of occurrence of diastolic Ca release events. Additionally, deep RNA sequencing identified 17 downregulated genes and 5 upregulated genes in DOX+ mice, among which Ppp1r13l, Clcn1, and Agt have previously been linked to arrhythmias. Our results suggest that conditional upregulation of SERCA2a exacerbates hyperactive RyR2-mediated arrhythmias by further elevating diastolic Ca release.
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Potenza DM, Janicek R, Fernandez-Tenorio M, Niggli E. Activation of endogenous protein phosphatase 1 enhances the calcium sensitivity of the ryanodine receptor type 2 in murine ventricular cardiomyocytes. J Physiol 2020; 598:1131-1150. [PMID: 31943206 DOI: 10.1113/jp278951] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/10/2020] [Indexed: 01/23/2023] Open
Abstract
KEY POINTS Increased protein phosphatase 1 (PP-1) activity has been found in end stage human heart failure. Although PP-1 has been extensively studied, a detailed understanding of its role in the excitation-contraction coupling mechanism, in normal and diseased hearts, remains elusive. The present study investigates the functional effect of the PP-1 activity on local Ca2+ release events in ventricular cardiomyocytes, by using an activating peptide (PDP3) for the stimulation of the endogenous PP-1 protein. We report that acute de-phosphorylation may increase the sensitivity of RyR2 channels to Ca2+ in situ, and that the RyR2-serine2808 phosphorylation site may mediate such a process. Our approach unmasks the functional importance of PP-1 in the regulation of RyR2 activity, suggesting a potential role in the generation of a pathophysiological sarcoplasmic reticulum Ca2+ leak in the diseased heart. ABSTRACT Changes in cardiac ryanodine receptor (RyR2) phosphorylation are considered to be important regulatory and disease related post-translational protein modifications. The extent of RyR2 phosphorylation is mainly determined by the balance of the activities of protein kinases and phosphatases, respectively. Increased protein phosphatase-1 (PP-1) activity has been observed in heart failure, although the regulatory role of this enzyme on intracellular Ca2+ handling remains poorly understood. To determine the physiological and pathophysiological significance of increased PP-1 activity, we investigated how the PP-1 catalytic subunit (PP-1c) alters Ca2+ sparks in permeabilized cardiomyocytes and we also applied a PP-1-disrupting peptide (PDP3) to specifically activate endogenous PP-1, including the one anchored on the RyR2 macromolecular complex. We compared wild-type and transgenic mice in which the usually highly phosphorylated site RyR2-S2808 has been ablated to investigate its involvement in RyR2 modulation (S2808A+/+ ). In wild-type myocytes, PP-1 increased Ca2+ spark frequency by two-fold, followed by depletion of the sarcoplasmic reticulum Ca2+ store. Similarly, PDP3 transiently increased spark frequency and decreased sarcoplasmic reticulum Ca2+ load. RyR2 Ca2+ sensitivity, which was assessed by Ca2+ spark recovery analysis, was increased in the presence of PDP3 compared to a negative control peptide. S2808A+/+ cardiomyocytes did not respond to both PP-1c and PDP3 treatment. Our results suggest an increased Ca2+ sensitivity of RyR2 upon de-phosphorylation by PP-1. Furthermore, we have confirmed the S2808 site as a target for PP-1 and as a potential link between RyR2s modulation and the cellular response.
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Affiliation(s)
| | | | | | - Ernst Niggli
- Department of Physiology, University of Bern, Bern, Switzerland
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Kim JC, Pérez-Hernández M, Alvarado FJ, Maurya SR, Montnach J, Yin Y, Zhang M, Lin X, Vasquez C, Heguy A, Liang FX, Woo SH, Morley GE, Rothenberg E, Lundby A, Valdivia HH, Cerrone M, Delmar M. Disruption of Ca 2+i Homeostasis and Connexin 43 Hemichannel Function in the Right Ventricle Precedes Overt Arrhythmogenic Cardiomyopathy in Plakophilin-2-Deficient Mice. Circulation 2019; 140:1015-1030. [PMID: 31315456 DOI: 10.1161/circulationaha.119.039710] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Plakophilin-2 (PKP2) is classically defined as a desmosomal protein. Mutations in PKP2 associate with most cases of gene-positive arrhythmogenic right ventricular cardiomyopathy. A better understanding of PKP2 cardiac biology can help elucidate the mechanisms underlying arrhythmic and cardiomyopathic events consequent to PKP2 deficiency. Here, we sought to capture early molecular/cellular events that can act as nascent arrhythmic/cardiomyopathic substrates. METHODS We used multiple imaging, biochemical and high-resolution mass spectrometry methods to study functional/structural properties of cells/tissues derived from cardiomyocyte-specific, tamoxifen-activated, PKP2 knockout mice (PKP2cKO) 14 days post-tamoxifen injection, a time point preceding overt electrical or structural phenotypes. Myocytes from right or left ventricular free wall were studied separately. RESULTS Most properties of PKP2cKO left ventricular myocytes were not different from control; in contrast, PKP2cKO right ventricular (RV) myocytes showed increased amplitude and duration of Ca2+ transients, increased Ca2+ in the cytoplasm and sarcoplasmic reticulum, increased frequency of spontaneous Ca2+ release events (sparks) even at comparable sarcoplasmic reticulum load, and dynamic Ca2+ accumulation in mitochondria. We also observed early- and delayed-after transients in RV myocytes and heightened susceptibility to arrhythmias in Langendorff-perfused hearts. In addition, ryanodine receptor 2 in PKP2cKO-RV cells presented enhanced Ca2+ sensitivity and preferential phosphorylation in a domain known to modulate Ca2+ gating. RNAseq at 14 days post-tamoxifen showed no relevant difference in transcript abundance between RV and left ventricle, neither in control nor in PKP2cKO cells. Instead, we found an RV-predominant increase in membrane permeability that can permit Ca2+ entry into the cell. Connexin 43 ablation mitigated the membrane permeability increase, accumulation of cytoplasmic Ca2+, increased frequency of sparks and early stages of RV dysfunction. Connexin 43 hemichannel block with GAP19 normalized [Ca2+]i homeostasis. Similarly, protein kinase C inhibition normalized spark frequency at comparable sarcoplasmic reticulum load levels. CONCLUSIONS Loss of PKP2 creates an RV-predominant arrhythmogenic substrate (Ca2+ dysregulation) that precedes the cardiomyopathy; this is, at least in part, mediated by a Connexin 43-dependent membrane conduit and repressed by protein kinase C inhibitors. Given that asymmetric Ca2+ dysregulation precedes the cardiomyopathic stage, we speculate that abnormal Ca2+ handling in RV myocytes can be a trigger for gross structural changes observed at a later stage.
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Affiliation(s)
- Joon-Chul Kim
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Marta Pérez-Hernández
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Francisco J Alvarado
- Department of Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health (F.J.A., H.H.V.)
| | - Svetlana R Maurya
- Department of Biomedical Sciences (S.R.M., A.L.), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Jerome Montnach
- Institut du Thorax, Nouvelle Universite a Nantes, INSERM, Nantes Cedex 1, France (J.M.)
| | - Yandong Yin
- Department of Pharmacology and Biochemistry (Y.Y., E.R.), New York University School of Medicine
| | - Mingliang Zhang
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Xianming Lin
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Carolina Vasquez
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Adriana Heguy
- Department of Pathology and Genome Technology Center (A.H., G.E.M.), New York University School of Medicine
| | - Feng-Xia Liang
- Microscopy Laboratory, Division of Advanced Research Technologies (F.X.L.), New York University School of Medicine
| | - Sun-Hee Woo
- Laboratory of Physiology, College of Pharmacy, Chungam National University, Daejeon, South Korea (S.H.W.)
| | - Gregory E Morley
- Department of Pathology and Genome Technology Center (A.H., G.E.M.), New York University School of Medicine
| | - Eli Rothenberg
- Department of Pharmacology and Biochemistry (Y.Y., E.R.), New York University School of Medicine
| | - Alicia Lundby
- Department of Biomedical Sciences (S.R.M., A.L.), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.,NNF Center for Protein Research (A.L.), Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Hector H Valdivia
- Department of Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health (F.J.A., H.H.V.)
| | - Marina Cerrone
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
| | - Mario Delmar
- The Leon H. Charney Division of Cardiology (J.C.K., M.P.H., M.Z., X.L., C.V., M.C., M.D.), New York University School of Medicine
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Liu B, Walton SD, Ho HT, Belevych AE, Tikunova SB, Bonilla I, Shettigar V, Knollmann BC, Priori SG, Volpe P, Radwański PB, Davis JP, Györke S. Gene Transfer of Engineered Calmodulin Alleviates Ventricular Arrhythmias in a Calsequestrin-Associated Mouse Model of Catecholaminergic Polymorphic Ventricular Tachycardia. J Am Heart Assoc 2018; 7:JAHA.117.008155. [PMID: 29720499 PMCID: PMC6015318 DOI: 10.1161/jaha.117.008155] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a familial arrhythmogenic syndrome characterized by sudden death. There are several genetic forms of CPVT associated with mutations in genes encoding the cardiac ryanodine receptor (RyR2) and its auxiliary proteins including calsequestrin (CASQ2) and calmodulin (CaM). It has been suggested that impairment of the ability of RyR2 to stay closed (ie, refractory) during diastole may be a common mechanism for these diseases. Here, we explore the possibility of engineering CaM variants that normalize abbreviated RyR2 refractoriness for subsequent viral‐mediated delivery to alleviate arrhythmias in non–CaM‐related CPVT. Methods and Results To that end, we have designed a CaM protein (GSH‐M37Q; dubbed as therapeutic CaM or T‐CaM) that exhibited a slowed N‐terminal Ca dissociation rate and prolonged RyR2 refractoriness in permeabilized myocytes derived from CPVT mice carrying the CASQ2 mutation R33Q. This T‐CaM was introduced to the heart of R33Q mice through recombinant adeno‐associated viral vector serotype 9. Eight weeks postinfection, we performed confocal microscopy to assess Ca handling and recorded surface ECGs to assess susceptibility to arrhythmias in vivo. During catecholamine stimulation with isoproterenol, T‐CaM reduced isoproterenol‐promoted diastolic Ca waves in isolated CPVT cardiomyocytes. Importantly, T‐CaM exposure abolished ventricular tachycardia in CPVT mice challenged with catecholamines. Conclusions Our results suggest that gene transfer of T‐CaM by adeno‐associated viral vector serotype 9 improves myocyte Ca handling and alleviates arrhythmias in a calsequestrin‐associated CPVT model, thus supporting the potential of a CaM‐based antiarrhythmic approach as a therapeutic avenue for genetically distinct forms of CPVT.
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Affiliation(s)
- Bin Liu
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH.,Department of Biological Sciences, Mississippi State University, Starkville, MI
| | - Shane D Walton
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH
| | - Hsiang-Ting Ho
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH
| | - Andriy E Belevych
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH
| | - Svetlana B Tikunova
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH
| | - Ingrid Bonilla
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH
| | - Vikram Shettigar
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH
| | - Bjorn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, Vanderbilt, TN
| | - Silvia G Priori
- Division of Cardiology and Molecular Cardiology, Maugeri Foundation-University of Pavia, Italy
| | - Pompeo Volpe
- Department of Biomedical Sciences, University of Padova, Italy
| | - Przemysław B Radwański
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH
| | - Jonathan P Davis
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH
| | - Sándor Györke
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, OH
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Vasostatin-1 Stops Structural Remodeling and Improves Calcium Handling via the eNOS-NO-PKG Pathway in Rat Hearts Subjected to Chronic β-Adrenergic Receptor Activation. Cardiovasc Drugs Ther 2017; 30:455-464. [PMID: 27595734 DOI: 10.1007/s10557-016-6687-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE Chronically elevated catecholamine levels activate cardiac β-adrenergic receptors, which play a vital role in the pathogenesis of heart failure. Evidence suggests that vasostatin-1 (VS-1) exerts anti-adrenergic effects on isolated and perfused hearts in vitro. Whether VS-1 ameliorates hypertrophy/remodeling by inducing the chronic activation of β-adrenergic receptors is unknown. The present study aims to test the efficacy of using VS-1 to treat the advanced hypertrophy/remodeling that result from chronic β-adrenergic receptor activation and to determine the cellular and molecular mechanisms that underlie this response. METHODS AND RESULT Rats were subjected to infusion with either isoprenaline (ISO, 5 mg/kg/d), ISO plus VS-1 (30 mg/kg/d) or placebo for 2 weeks. VS-1 suppressed chamber dilation, myocyte hypertrophy and fibrosis and improved in vivo heart function in the rats subjected to ISO infusion. VS-1 increased phosphorylated nitric oxide synthase levels and induced the activation of protein kinase G. VS-1 also deactivated multiple hypertrophy signaling pathways that were triggered by the chronic activation of β-adrenergic receptors, such as the phosphoinositide-3 kinase (PI3K)/Akt and Ca2+/calmodulin-dependent kinase (CaMK-II) pathways. Myocytes isolated from ISO + VS-1 hearts displayed higher Ca2+ transients, shorter Ca2+ decays, higher sarcoplasmic reticulum Ca2+ levels and higher L-type Ca2+ current densities than the ISO rat hearts. VS-1 treatment restored the protein expression of sarcoplasmic reticulum Ca2+ uptake ATPase, phospholamban and Cav1.2, indicating improved calcium handling. CONCLUSIONS Chronic VS-1 treatment inhibited the progression of hypertrophy, fibrosis, and chamber remodeling, and improved cardiac function in a rat model of ISO infusion. In addition, Ca2+ handling and its molecular modulation were also improved by VS-1. The beneficial effects of VS-1 on cardiac remodeling may be mediated by the enhanced activation of the eNOS-cGMP-PKG pathway.
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The effect of PKA-mediated phosphorylation of ryanodine receptor on SR Ca 2+ leak in ventricular myocytes. J Mol Cell Cardiol 2017; 104:9-16. [PMID: 28131630 DOI: 10.1016/j.yjmcc.2017.01.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/22/2016] [Accepted: 01/24/2017] [Indexed: 01/08/2023]
Abstract
Functional impact of cardiac ryanodine receptor (type 2 RyR or RyR2) phosphorylation by protein kinase A (PKA) remains highly controversial. In this study, we characterized a functional link between PKA-mediated RyR2 phosphorylation level and sarcoplasmic reticulum (SR) Ca2+ release and leak in permeabilized rabbit ventricular myocytes. Changes in cytosolic [Ca2+] and intra-SR [Ca2+]SR were measured with Fluo-4 and Fluo-5N, respectively. Changes in RyR2 phosphorylation at two PKA sites, serine-2031 and -2809, were measured with phospho-specific antibodies. cAMP (10μM) increased Ca2+ spark frequency approximately two-fold. This effect was associated with an increase in SR Ca2+ load from 0.84 to 1.24mM. PKA inhibitory peptide (PKI; 10μM) abolished the cAMP-dependent increase of SR Ca2+ load and spark frequency. When SERCA was completely blocked by thapsigargin, cAMP did not affect RyR2-mediated Ca2+ leak. The lack of a cAMP effect on RyR2 function can be explained by almost maximal phosphorylation of RyR2 at serine-2809 after sarcolemma permeabilization. This high RyR2 phosphorylation level is likely the consequence of a balance shift between protein kinase and phosphatase activity after permeabilization. When RyR2 phosphorylation at serine-2809 was reduced to its "basal" level (i.e. RyR2 phosphorylation level in intact myocytes) using kinase inhibitor staurosporine, SR Ca2+ leak was significantly reduced. Surprisingly, further dephosphorylation of RyR2 with protein phosphatase 1 (PP1) markedly increased SR Ca2+ leak. At the same time, phosphorylation of RyR2 at serine 2031 did not significantly change under identical experimental conditions. These results suggest that RyR2 phosphorylation by PKA has a complex effect on SR Ca2+ leak in ventricular myocytes. At an intermediate level of RyR2 phosphorylation SR Ca2+ leak is minimal. However, complete dephosphorylation and maximal phosphorylation of RyR2 increases SR Ca2+ leak.
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Alvarado FJ, Chen X, Valdivia HH. Ablation of the cardiac ryanodine receptor phospho-site Ser2808 does not alter the adrenergic response or the progression to heart failure in mice. Elimination of the genetic background as critical variable. J Mol Cell Cardiol 2017; 103:40-47. [PMID: 28065668 DOI: 10.1016/j.yjmcc.2017.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 01/04/2017] [Indexed: 10/20/2022]
Abstract
BACKGROUND Phosphorylation of the cardiac ryanodine receptor (RyR2) phospho-site S2808 has been touted by the Marks group as a hallmark of heart failure (HF) and a critical mediator of the physiological fight-or-flight response of the heart. In support of this hypothesis, mice unable to undergo phosphorylation at RyR2-S2808 (S2808A) were significantly protected against HF and displayed a blunted response to adrenergic stimulation. However, the issue remains highly controversial because several groups have been unable to reproduce these findings. An important variable not considered before is the genetic background of the mice used to obtain these divergent results. METHODS AND RESULTS We backcrossed a RyR2-S2808A mouse into a congenic C57Bl/6 strain, the same strain used by the Marks group to conduct their experiments. We then performed several key experiments to confirm or discard the genetic background of the mouse as a relevant variable, including induction of HF by myocardial infarction and tests of integrity of adrenergic response. Congenic C57Bl/6 harboring the S2808A mutation showed similar echocardiographic parameters that indicated identical progression towards HF compared to wild type controls, and had a normal response to adrenergic stimulation in whole animal and cellular experiments. CONCLUSIONS The genetic background of the different mouse models is unlikely to be the source of the divergent results obtained by the Marks group in comparison to several other groups. Cardiac adrenergic response and progression towards HF proceed unaltered in mice harboring the RyR2-S2808A mutation. Preventing RyR2-S2808 phosphorylation does not preclude a normal sympathetic response nor mitigates the pathophysiological consequences of MI.
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Affiliation(s)
- Francisco J Alvarado
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States.
| | - Xi Chen
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States
| | - Héctor H Valdivia
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, United States; Center for Arrhythmia Research, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, United States.
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Terentyev D, Hamilton S. Regulation of sarcoplasmic reticulum Ca 2+ release by serine-threonine phosphatases in the heart. J Mol Cell Cardiol 2016; 101:156-164. [PMID: 27585747 DOI: 10.1016/j.yjmcc.2016.08.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 08/26/2016] [Accepted: 08/27/2016] [Indexed: 12/17/2022]
Abstract
The amount and timing of Ca2+ release from the sarcoplasmic reticulum (SR) during cardiac cycle are the main determinants of cardiac contractility. Reversible phosphorylation of the SR Ca2+ release channel, ryanodine receptor type 2 (RyR2) is the central mechanism of regulation of Ca2+ release in cardiomyocytes. Three major serine-threonine phosphatases including PP1, PP2A and PP2B (calcineurin) have been implicated in modulation of RyR2 function. Changes in expression levels of these phosphatases, their activity and targeting to the RyR2 macromolecular complex were demonstrated in many animal models of cardiac disease and humans and are implicated in cardiac arrhythmia and heart failure. Here we review evidence in support of regulation of RyR2-mediated SR Ca2+ release by serine-threonine phosphatases and the role and mechanisms of dysregulation of phosphatases in various disease states.
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Affiliation(s)
- Dmitry Terentyev
- The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Department of Medicine, Cardiovascular Research Center, United States.
| | - Shanna Hamilton
- Cardiff University, School of Medicine, Wales Heart Research Institute, United Kingdom
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Radwański PB, Ho HT, Veeraraghavan R, Brunello L, Liu B, Belevych AE, Unudurthi SD, Makara MA, Priori SG, Volpe P, Armoundas AA, Dillmann WH, Knollmann BC, Mohler PJ, Hund TJ, Györke S. Neuronal Na + Channels Are Integral Components of Pro-arrhythmic Na +/Ca 2+ Signaling Nanodomain That Promotes Cardiac Arrhythmias During β-adrenergic Stimulation. JACC Basic Transl Sci 2016; 1:251-266. [PMID: 27747307 PMCID: PMC5065245 DOI: 10.1016/j.jacbts.2016.04.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Cardiac arrhythmias are a leading cause of death in the US. Vast majority of these arrhythmias including catecholaminergic polymorphic ventricular tachycardia (CPVT) are associated with increased levels of circulating catecholamines and involve abnormal impulse formation secondary to aberrant Ca2+ and Na+ handling. However, the mechanistic link between β-AR stimulation and the subcellular/molecular arrhythmogenic trigger(s) remains elusive. METHODS AND RESULTS We performed functional and structural studies to assess Ca2+ and Na+ signaling in ventricular myocyte as well as surface electrocardiograms in mouse models of cardiac calsequestrin (CASQ2)-associated CPVT. We demonstrate that a subpopulation of Na+ channels (neuronal Na+ channels; nNav) that colocalize with RyR2 and Na+/Ca2+ exchanger (NCX) are a part of the β-AR-mediated arrhythmogenic process. Specifically, augmented Na+ entry via nNav in the settings of genetic defects within the RyR2 complex and enhanced sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA)-mediated SR Ca2+ refill is both an essential and a necessary factor for the arrhythmogenesis. Furthermore, we show that augmentation of Na+ entry involves β-AR-mediated activation of CAMKII subsequently leading to nNav augmentation. Importantly, selective pharmacological inhibition as well as silencing of Nav1.6 inhibit myocyte arrhythmic potential and prevent arrhythmias in vivo. CONCLUSION These data suggest that the arrhythmogenic alteration in Na+/Ca2+ handling evidenced ruing β-AR stimulation results, at least in part, from enhanced Na+ influx through nNav. Therefore, selective inhibition of these channels and Nav1.6 in particular can serve as a potential antiarrhythmic therapy.
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Affiliation(s)
- Przemysław B Radwański
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US ; Division of Pharmacy Practice and Sciences, College of Pharmacy, The Ohio State University, Columbus, OH, US
| | - Hsiang-Ting Ho
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Rengasayee Veeraraghavan
- Center for Heart and Regenerative Medicine Research, Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, VA, USA
| | - Lucia Brunello
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Bin Liu
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Andriy E Belevych
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Sathya D Unudurthi
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, OH, USA
| | - Michael A Makara
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Silvia G Priori
- Division of Cardiology and Molecular Cardiology, Maugeri Foundation-University of Pavia, Pavia, Italy
| | - Pompeo Volpe
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, Charlestown, MA, USA
| | - Wolfgang H Dillmann
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Bjorn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University Medical School, Nashville, TN, USA
| | - Peter J Mohler
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
| | - Thomas J Hund
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Center for Heart and Regenerative Medicine Research, Virginia Tech Carilion Research Institute, Virginia Polytechnic University, Roanoke, VA, USA
| | - Sándor Györke
- Dorothy M. Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA ; Department of Physiology and Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, US
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Beta-Adrenoceptor Stimulation Reveals Ca2+ Waves and Sarcoplasmic Reticulum Ca2+ Depletion in Left Ventricular Cardiomyocytes from Post-Infarction Rats with and without Heart Failure. PLoS One 2016; 11:e0153887. [PMID: 27096943 PMCID: PMC4838269 DOI: 10.1371/journal.pone.0153887] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 04/05/2016] [Indexed: 11/25/2022] Open
Abstract
Abnormal cellular Ca2+ handling contributes to both contractile dysfunction and arrhythmias in heart failure. Reduced Ca2+ transient amplitude due to decreased sarcoplasmic reticulum Ca2+ content is a common finding in heart failure models. However, heart failure models also show increased propensity for diastolic Ca2+ release events which occur when sarcoplasmic reticulum Ca2+ content exceeds a certain threshold level. Such Ca2+ release events can initiate arrhythmias. In this study we aimed to investigate if both of these aspects of altered Ca2+ homeostasis could be found in left ventricular cardiomyocytes from rats with different states of cardiac function six weeks after myocardial infarction when compared to sham-operated controls. Video edge-detection, whole-cell Ca2+ imaging and confocal line-scan imaging were used to investigate cardiomyocyte contractile properties, Ca2+ transients and Ca2+ waves. In baseline conditions, i.e. without beta-adrenoceptor stimulation, cardiomyocytes from rats with large myocardial infarction, but without heart failure, did not differ from sham-operated animals in any of these aspects of cellular function. However, when exposed to beta-adrenoceptor stimulation, cardiomyocytes from both non-failing and failing rat hearts showed decreased sarcoplasmic reticulum Ca2+ content, decreased Ca2+ transient amplitude, and increased frequency of Ca2+ waves. These results are in line with a decreased threshold for diastolic Ca2+ release established by other studies. In the present study, factors that might contribute to a lower threshold for diastolic Ca2+ release were increased THR286 phosphorylation of Ca2+/calmodulin-dependent protein kinase II and increased protein phosphatase 1 abundance. In conclusion, this study demonstrates both decreased sarcoplasmic reticulum Ca2+ content and increased propensity for diastolic Ca2+ release events in ventricular cardiomyocytes from rats with heart failure after myocardial infarction, and that these phenomena are also found in rats with large myocardial infarctions without heart failure development. Importantly, beta-adrenoceptor stimulation is necessary to reveal these perturbations in Ca2+ handling after a myocardial infarction.
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The ryanodine receptor provides high throughput Ca2+-release but is precisely regulated by networks of associated proteins: a focus on proteins relevant to phosphorylation. Biochem Soc Trans 2016; 43:426-33. [PMID: 26009186 DOI: 10.1042/bst20140297] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Once opened, ryanodine receptors (RyR) are efficient pathways for the release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR). The precise nature of the Ca2+-release event, however, requires fine-tuning for the specific process and type of cell involved. For example, the spatial organization of RyRs, the luminal [Ca2+] and the influence of soluble regulators that fluctuate under physiological and pathophysiological control mechanisms, all affect the amplitude and duration of RyR Ca2+ fluxes. Various proteins are docked tightly to the huge bulky structure of RyR and there is growing evidence that, together, they provide a sophisticated and integrated system for regulating RyR channel gating. This review focuses on those proteins that are relevant to phosphorylation of RyR channels with particular reference to the cardiac isoform of RyR (RyR2). How phosphorylation of RyR affects channel activity and whether proteins such as the FK-506 binding proteins (FKBP12 and FKBP12.6) are involved, have been highly controversial subjects for more than a decade. But that is expected given the large number of participating proteins, the relevance of phosphorylation in heart failure and inherited arrhythmic diseases, and the frustrations of predicting relationships between structure and function before the advent of a high resolution structure of RyR.
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Weber S, Meyer-Roxlau S, Wagner M, Dobrev D, El-Armouche A. Counteracting Protein Kinase Activity in the Heart: The Multiple Roles of Protein Phosphatases. Front Pharmacol 2015; 6:270. [PMID: 26617522 PMCID: PMC4643138 DOI: 10.3389/fphar.2015.00270] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 10/28/2015] [Indexed: 12/19/2022] Open
Abstract
Decades of cardiovascular research have shown that variable and flexible levels of protein phosphorylation are necessary to maintain cardiac function. A delicate balance between phosphorylated and dephosphorylated states of proteins is guaranteed by a complex interplay of protein kinases (PKs) and phosphatases. Serine/threonine phosphatases, in particular members of the protein phosphatase (PP) family govern dephosphorylation of the majority of these cardiac proteins. Recent findings have however shown that PPs do not only dephosphorylate previously phosphorylated proteins as a passive control mechanism but are capable to actively control PK activity via different direct and indirect signaling pathways. These control mechanisms can take place on (epi-)genetic, (post-)transcriptional, and (post-)translational levels. In addition PPs themselves are targets of a plethora of proteinaceous interaction partner regulating their endogenous activity, thus adding another level of complexity and feedback control toward this system. Finally, novel approaches are underway to achieve spatiotemporal pharmacologic control of PPs which in turn can be used to fine-tune misleaded PK activity in heart disease. Taken together, this review comprehensively summarizes the major aspects of PP-mediated PK regulation and discusses the subsequent consequences of deregulated PP activity for cardiovascular diseases in depth.
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Affiliation(s)
- Silvio Weber
- Department of Pharmacology and Toxicology, Dresden University of Technology , Dresden, Germany
| | - Stefanie Meyer-Roxlau
- Department of Pharmacology and Toxicology, Dresden University of Technology , Dresden, Germany
| | - Michael Wagner
- Department of Pharmacology and Toxicology, Dresden University of Technology , Dresden, Germany
| | - Dobromir Dobrev
- Institute of Pharmacology, Faculty of Medicine, West German Heart and Vascular Center , Essen, Germany
| | - Ali El-Armouche
- Department of Pharmacology and Toxicology, Dresden University of Technology , Dresden, Germany
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20
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Liu B, Ho HT, Brunello L, Unudurthi SD, Lou Q, Belevych AE, Qian L, Kim DH, Cho C, Janssen PML, Hund TJ, Knollmann BC, Kranias EG, Györke S. Ablation of HRC alleviates cardiac arrhythmia and improves abnormal Ca handling in CASQ2 knockout mice prone to CPVT. Cardiovasc Res 2015; 108:299-311. [PMID: 26410369 DOI: 10.1093/cvr/cvv222] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 09/17/2015] [Indexed: 01/02/2023] Open
Abstract
AIMS Cardiac calsequestrin (CASQ2) and histidine-rich Ca-binding protein (HRC) are sarcoplasmic reticulum (SR) Ca-binding proteins that regulate SR Ca release in mammalian heart. Deletion of either CASQ2 or HRC results in relatively mild phenotypes characterized by preserved cardiac structure and function, although CASQ2 knockout (KO), or Cnull, shows increased arrhythmia burden under conditions of catecholaminergic stress. We hypothesized that given the apparent overlap of functions of CASQ2 and HRC, simultaneous ablation of both would deteriorate the cardiac phenotype compared with the single knockouts. METHODS AND RESULTS In contrast to this expectation, double knockout (DKO) mice lacking both CASQ2 and HRC exhibited normal cardiac ejection fraction and ultrastructure. Moreover, the predisposition to catecholamine-dependent arrhythmia that characterizes the Cnull phenotype was alleviated in the DKO mice. At the myocyte level, DKO mice displayed Ca transients of normal amplitude; additionally, the frequency of spontaneous Ca waves and sparks in the presence of isoproterenol were decreased markedly compared with Cnull. Furthermore, restitution of SR Ca release was slowed in DKO myocytes compared with Cnull cells. CONCLUSION Our results suggest that rather than being functionally redundant, CASQ2 and HRC modulate cardiac ryanodine receptor-mediated (RyR2) Ca release in an opposing manner. In particular, while CASQ2 stabilizes RyR2 rendering it refractory in the diastolic phase, HRC enhances RyR2 activity facilitating RyR2 recovery from refractoriness.
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Affiliation(s)
- Bin Liu
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
| | - Hsiang-Ting Ho
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
| | - Lucia Brunello
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
| | - Sathya D Unudurthi
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
| | - Qing Lou
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
| | - Andriy E Belevych
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
| | - Lan Qian
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
| | - Do Han Kim
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Chunghee Cho
- School of Life Sciences and Systems Biology Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
| | - Thomas J Hund
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
| | - Bjorn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University Medical School, Nashville, TN 37232, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Sándor Györke
- Department of Physiology and Cell Biology, College of Medicine, and Davis Heart and Lung Research Institute, The Ohio State University, 473 W. 12th Avenue, Columbus, OH 43210, USA
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21
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Lei M, Wang X, Ke Y, Solaro RJ. Regulation of Ca(2+) transient by PP2A in normal and failing heart. Front Physiol 2015; 6:13. [PMID: 25688213 PMCID: PMC4310266 DOI: 10.3389/fphys.2015.00013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/09/2015] [Indexed: 11/13/2022] Open
Abstract
Calcium transient in cardiomyocytes is regulated by multiple protein kinases and phosphatases. PP2A is a major protein phosphatase in the heart modulating Ca2+ handling through an array of ion channels, antiporters and pumps, etc. The assembly, localization/translocation, and substrate specificity of PP2A are controlled by different post-translational mechanisms, which in turn are linked to the activities of upstream signaling molecules. Abnormal PP2A expression and activities are associated with defective response to β-adrenergic stimulation and are indication and causal factors in arrhythmia and heart failure.
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Affiliation(s)
- Ming Lei
- Department of Pharmacology, University of Oxford Oxford, UK
| | - Xin Wang
- Faculty of Life Science, University of Manchester Manchester, UK
| | - Yunbo Ke
- Department of Physiology and Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago Chicago, IL, USA
| | - R John Solaro
- Department of Physiology and Biophysics, Center for Cardiovascular Research, University of Illinois at Chicago Chicago, IL, USA
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22
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Backx PH. Complexity, confusion and controversy continue complicating the contribution of RyR2 channel phosphorylation to heart function. J Physiol 2015; 592:1911-2. [PMID: 24786150 DOI: 10.1113/jphysiol.2014.272575] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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23
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Lou Q, Belevych AE, Radwański PB, Liu B, Kalyanasundaram A, Knollmann BC, Fedorov VV, Györke S. Alternating membrane potential/calcium interplay underlies repetitive focal activity in a genetic model of calcium-dependent atrial arrhythmias. J Physiol 2014; 593:1443-58. [PMID: 25384790 DOI: 10.1113/jphysiol.2014.280784] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 10/23/2014] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS Atrial fibrillation is often initiated and perpetuated by abnormal electrical pulses repetitively originating from regions outside the heart's natural pacemaker. In this study we examined the causal role of abnormal calcium releases from the sarcoplasmic reticulum in producing repetitive electrical discharges in atrial cells and tissues. Calsequestrin2 is a protein that stabilizes the closed state of calcium release channels, i.e. the ryanodine receptors. In the atria from mice predisposed to abnormal calcium releases secondary to the absence of calsequestrin2, we observed abnormal repetitive electrical discharges that may lead to atrial fibrillation. Here, we report a novel pathological rhythm generator. Specifically, abnormal calcium release leads to electrical activation, which in turn results in another abnormal calcium release. This process repeats itself and thus sustains the repetitive electrical discharges. These results suggest that improving the stability of ryanodine receptors might be useful to treat atrial fibrillation. ABSTRACT Aberrant diastolic calcium (Ca) release due to leaky ryanodine receptors (RyR2s) has been recently associated with atrial fibrillation (AF) and catecholaminergic polymorphic ventricular tachycardia (CPVT). However, it remains unclear how diastolic Ca release contributes to the rising of rapid repetitive focal activity, which is considered as a common AF triggering mechanism. To address this question, we conducted simultaneous voltage/Ca optical mapping in atrial tissue and one-/two-dimensional confocal imaging in atrial tissue and myocytes from wild-type (WT, n = 15) and CPVT mice lacking calsequestrin 2 (Casq2(-/-), n = 45), which promotes diastolic Ca release. During β-adrenergic stimulation (100 nM isoproterenol), only Casq2(-/-) atrial myocytes showed pacing-induced self-sustained repetitive activity (31 ± 21 s vs. none in WT). Importantly, in atrial tissue, this repetitive activity could translate to Ca-dependent focal arrhythmia. Ectopic action potential (AP) firing during repetitive activity occurred only when diastolic Ca release achieved a sufficient level of synchronization. The AP, in turn, synchronized subsequent diastolic Ca release by temporally aligning multiple sources of Ca waves both within individual myocytes and throughout the atrial tissue. This alternating interplay between AP and diastolic Ca release perpetuates the self-sustaining repetitive activity. In fact, pharmacological disruption of synchronized diastolic Ca release (by ryanodine) prevented aberrant APs; and vice versa, the inhibition of AP (by TTX or 0 Na, 0 Ca solution) de-synchronized diastolic Ca release. Taken together, these results suggest that a cyclical interaction between synchronized diastolic Ca release and AP forms a pathological rhythm generator that is involved in Ca-dependent atrial arrhythmias in CPVT.
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Affiliation(s)
- Qing Lou
- Department of Physiology & Cell Biology, College of Medicine, The Ohio State University, Columbus, OH, USA; Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, USA
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Poláková E, Illaste A, Niggli E, Sobie EA. Maximal acceleration of Ca2+ release refractoriness by β-adrenergic stimulation requires dual activation of kinases PKA and CaMKII in mouse ventricular myocytes. J Physiol 2014; 593:1495-507. [PMID: 25772298 DOI: 10.1113/jphysiol.2014.278051] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 08/30/2014] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Refractoriness of calcium release in heart cells is altered in several disease states, but the physiological mechanisms that regulate this process are incompletely understood. We examined refractoriness of calcium release in mouse ventricular myocytes and investigated how activation of different intracellular signalling pathways influenced this process. We found that refractoriness of calcium release is abbreviated by stimulation of the 'fight-or-flight' response, and that simultaneous activation of multiple intracellular signalling pathways contributes to this response. Data obtained under several conditions at the subcellular, microscopic level were consistent with results obtained at the cellular level. The results provide insight into regulation of cardiac calcium release and how alterations to this process may increase arrhythmia risk under different conditions. ABSTRACT Time-dependent refractoriness of calcium (Ca(2+)) release in cardiac myocytes is an important factor in determining whether pro-arrhythmic release patterns develop. At the subcellular level of the Ca(2+) spark, recent studies have suggested that recovery of spark amplitude is controlled by local sarcoplasmic reticulum (SR) refilling whereas refractoriness of spark triggering depends on both refilling and the sensitivity of the ryanodine receptor (RyR) release channels that produce sparks. Here we studied regulation of Ca(2+) spark refractoriness in mouse ventricular myocytes by examining how β-adrenergic stimulation influenced sequences of Ca(2+) sparks originating from individual RyR clusters. Our protocol allowed us to separately measure recovery of spark amplitude and delays between successive sparks, and data were interpreted quantitatively through simulations with a stochastic mathematical model. We found that, compared with spark sequences measured under control conditions: (1) β-adrenergic stimulation with isoproterenol (isoprenaline) accelerated spark amplitude recovery and decreased spark-to-spark delays; (2) activating protein kinase A (PKA) with forskolin accelerated amplitude recovery but did not affect spark-to-spark delays; (3) inhibiting PKA with H89 retarded amplitude recovery and increased spark-to-spark delays; (4) preventing phosphorylation of the RyR at serine 2808 with a knock-in mouse prevented the decrease in spark-to-spark delays seen with β-adrenergic stimulation; (5) inhibiting either PKA or Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) during β-adrenergic stimulation prevented the decrease in spark-to-spark delays seen without inhibition. The results suggest that activation of either PKA or CaMKII is sufficient to speed SR refilling, but activation of both kinases appears necessary to observe increased RyR sensitivity. The data provide novel insight into β-adrenergic regulation of Ca(2+) release refractoriness in mouse myocytes.
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Affiliation(s)
- Eva Poláková
- Department of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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25
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Dobrev D, Wehrens XHT. Role of RyR2 phosphorylation in heart failure and arrhythmias: Controversies around ryanodine receptor phosphorylation in cardiac disease. Circ Res 2014; 114:1311-9; discussion 1319. [PMID: 24723656 DOI: 10.1161/circresaha.114.300568] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cardiac ryanodine receptor type 2 plays a key role in excitation-contraction coupling. The ryanodine receptor type 2 channel protein is modulated by various post-translational modifications, including phosphorylation by protein kinase A and Ca(2+)/calmodulin protein kinase II. Despite extensive research in this area, the functional effects of ryanodine receptor type 2 phosphorylation remain disputed. In particular, the potential involvement of increased ryanodine receptor type 2 phosphorylation in the pathogenesis of heart failure and arrhythmias remains a controversial area, which is discussed in this review article.
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Affiliation(s)
- Dobromir Dobrev
- From the Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany (D.D.); and Cardiovascular Research Institute, Departments of Molecular Physiology and Biophysics, and Medicine-Cardiology, Baylor College of Medicine, Houston, TX (X.H.T.W.)
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