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Molecular Aspects Implicated in Dantrolene Selectivity with Respect to Ryanodine Receptor Isoforms. Int J Mol Sci 2023; 24:ijms24065409. [PMID: 36982484 PMCID: PMC10049336 DOI: 10.3390/ijms24065409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/24/2023] [Accepted: 03/10/2023] [Indexed: 03/14/2023] Open
Abstract
Dantrolene is an intra-cellularly acting skeletal muscle relaxant used for the treatment of the rare genetic disorder, malignant hyperthermia (MH). In most cases, MH susceptibility is caused by dysfunction of the skeletal ryanodine receptor (RyR1) harboring one of nearly 230 single-point MH mutations. The therapeutic effect of dantrolene is the result of a direct inhibitory action on the RyR1 channel, thus suppressing aberrant Ca2+ release from the sarcoplasmic reticulum. Despite the almost identical dantrolene-binding sequence exits in all three mammalian RyR isoforms, dantrolene appears to be an isoform-selective inhibitor. Whereas RyR1 and RyR3 channels are competent to bind dantrolene, the RyR2 channel, predominantly expressed in the heart, is unresponsive. However, a large body of evidence suggests that the RyR2 channel becomes sensitive to dantrolene-mediated inhibition under certain pathological conditions. Although a consistent picture of the dantrolene effect emerges from in vivo studies, in vitro results are often contradictory. Hence, our goal in this perspective is to provide the best possible clues to the molecular mechanism of dantrolene’s action on RyR isoforms by identifying and discussing potential sources of conflicting results, mainly coming from cell-free experiments. Moreover, we propose that, specifically in the case of the RyR2 channel, its phosphorylation could be implicated in acquiring the channel responsiveness to dantrolene inhibition, interpreting functional findings in the structural context.
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Horváth B, Szentandrássy N, Almássy J, Dienes C, Kovács ZM, Nánási PP, Banyasz T. Late Sodium Current of the Heart: Where Do We Stand and Where Are We Going? Pharmaceuticals (Basel) 2022; 15:ph15020231. [PMID: 35215342 PMCID: PMC8879921 DOI: 10.3390/ph15020231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 02/05/2023] Open
Abstract
Late sodium current has long been linked to dysrhythmia and contractile malfunction in the heart. Despite the increasing body of accumulating information on the subject, our understanding of its role in normal or pathologic states is not complete. Even though the role of late sodium current in shaping action potential under physiologic circumstances is debated, it’s unquestioned role in arrhythmogenesis keeps it in the focus of research. Transgenic mouse models and isoform-specific pharmacological tools have proved useful in understanding the mechanism of late sodium current in health and disease. This review will outline the mechanism and function of cardiac late sodium current with special focus on the recent advances of the area.
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Affiliation(s)
- Balázs Horváth
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Norbert Szentandrássy
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
- Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, 4032 Debrecen, Hungary
| | - János Almássy
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Csaba Dienes
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Zsigmond Máté Kovács
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
| | - Péter P. Nánási
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
- Department of Dental Physiology and Pharmacology, University of Debrecen, 4032 Debrecen, Hungary
| | - Tamas Banyasz
- Department of Physiology, University of Debrecen, 4032 Debrecen, Hungary; (B.H.); (N.S.); (J.A.); (C.D.); (Z.M.K.); (P.P.N.)
- Correspondence: ; Tel.: +36-(52)-255-575; Fax: +36-(52)-255-116
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Carlson CR, Aronsen JM, Bergan-Dahl A, Moutty MC, Lunde M, Lunde PK, Jarstadmarken H, Wanichawan P, Pereira L, Kolstad TRS, Dalhus B, Subramanian H, Hille S, Christensen G, Müller OJ, Nikolaev V, Bers DM, Sjaastad I, Shen X, Louch WE, Klussmann E, Sejersted OM. AKAP18δ Anchors and Regulates CaMKII Activity at Phospholamban-SERCA2 and RYR. Circ Res 2022; 130:27-44. [PMID: 34814703 PMCID: PMC9500498 DOI: 10.1161/circresaha.120.317976] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The sarcoplasmic reticulum (SR) Ca2+-ATPase 2 (SERCA2) mediates Ca2+ reuptake into SR and thereby promotes cardiomyocyte relaxation, whereas the ryanodine receptor (RYR) mediates Ca2+ release from SR and triggers contraction. Ca2+/CaMKII (CaM [calmodulin]-dependent protein kinase II) regulates activities of SERCA2 through phosphorylation of PLN (phospholamban) and RYR through direct phosphorylation. However, the mechanisms for CaMKIIδ anchoring to SERCA2-PLN and RYR and its regulation by local Ca2+ signals remain elusive. The objective of this study was to investigate CaMKIIδ anchoring and regulation at SERCA2-PLN and RYR. METHODS A role for AKAP18δ (A-kinase anchoring protein 18δ) in CaMKIIδ anchoring and regulation was analyzed by bioinformatics, peptide arrays, cell-permeant peptide technology, immunoprecipitations, pull downs, transfections, immunoblotting, proximity ligation, FRET-based CaMKII activity and ELISA-based assays, whole cell and SR vesicle fluorescence imaging, high-resolution microscopy, adenovirus transduction, adenoassociated virus injection, structural modeling, surface plasmon resonance, and alpha screen technology. RESULTS Our results show that AKAP18δ anchors and directly regulates CaMKIIδ activity at SERCA2-PLN and RYR, via 2 distinct AKAP18δ regions. An N-terminal region (AKAP18δ-N) inhibited CaMKIIδ through binding of a region homologous to the natural CaMKII inhibitor peptide and the Thr17-PLN region. AKAP18δ-N also bound CaM, introducing a second level of control. Conversely, AKAP18δ-C, which shares homology to neuronal CaMKIIα activator peptide (N2B-s), activated CaMKIIδ by lowering the apparent Ca2+ threshold for kinase activation and inducing CaM trapping. While AKAP18δ-C facilitated faster Ca2+ reuptake by SERCA2 and Ca2+ release through RYR, AKAP18δ-N had opposite effects. We propose a model where the 2 unique AKAP18δ regions fine-tune Ca2+-frequency-dependent activation of CaMKIIδ at SERCA2-PLN and RYR. CONCLUSIONS AKAP18δ anchors and functionally regulates CaMKII activity at PLN-SERCA2 and RYR, indicating a crucial role of AKAP18δ in regulation of the heartbeat. To our knowledge, this is the first protein shown to enhance CaMKII activity in heart and also the first AKAP (A-kinase anchoring protein) reported to anchor a CaMKII isoform, defining AKAP18δ also as a CaM-KAP.
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Affiliation(s)
- Cathrine R. Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Jan Magnus Aronsen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo Norway,Department of Pharmacology, Oslo University Hospital, Norway
| | - Anna Bergan-Dahl
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Marie Christine Moutty
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Marianne Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Per Kristian Lunde
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Hilde Jarstadmarken
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Pimthanya Wanichawan
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Laetitia Pereira
- Department of Pharmacology, University of California at Davis, Davis, CA, USA
| | - Terje RS Kolstad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Bjørn Dalhus
- Department of Microbiology, Oslo University Hospital, Rikshospitalet, 0424 Oslo, Norway,Department of Medical Biochemistry, Institute for Clinical Medicine, University of Oslo, 0424 Oslo, Norway
| | - Hariharan Subramanian
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany,German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany
| | - Susanne Hille
- German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany,Department of Internal Medicine III, University of Kiel, Kiel, Germany
| | - Geir Christensen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Oliver J. Müller
- German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany,Department of Internal Medicine III, University of Kiel, Kiel, Germany
| | - Viacheslav Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany,German Centre for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Germany
| | - Donald M. Bers
- Department of Pharmacology, University of California at Davis, Davis, CA, USA
| | - Ivar Sjaastad
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Xin Shen
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - William E. Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
| | - Enno Klussmann
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany,German Centre for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany
| | - Ole M. Sejersted
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway,The KG Jebsen Cardiac Research Center, University of Oslo, Oslo, Norway
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Winkle AJ, Nassal DM, Shaheen R, Thomas E, Mohta S, Gratz D, Weinberg SH, Hund TJ. Emerging therapeutic targets for cardiac hypertrophy. Expert Opin Ther Targets 2022; 26:29-40. [PMID: 35076342 PMCID: PMC8885901 DOI: 10.1080/14728222.2022.2031974] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
INTRODUCTION Cardiac hypertrophy is associated with adverse outcomes across cardiovascular disease states. Despite strides over the last three decades in identifying molecular and cellular mechanisms driving hypertrophy, the link between pathophysiological stress stimuli and specific myocyte/heart growth profiles remains unclear. Moreover, the optimal strategy for preventing pathology in the setting of hypertrophy remains controversial. AREAS COVERED This review discusses molecular mechanisms underlying cardiac hypertrophy with a focus on factors driving the orientation of myocyte growth and the impact on heart function. We highlight recent work showing a novel role for the spectrin-based cytoskeleton, emphasizing regulation of myocyte dimensions but not hypertrophy per se. Finally, we consider opportunities for directing the orientation of myocyte growth in response to hypertrophic stimuli as an alternative therapeutic approach. Relevant publications on the topic were identified through Pubmed with open-ended search dates. EXPERT OPINION To define new therapeutic avenues, more precision is required when describing changes in myocyte and heart structure/function in response to hypertrophic stimuli. Recent developments in computational modeling of hypertrophic networks, in concert with more refined experimental approaches will catalyze translational discovery to advance the field and further our understanding of cardiac hypertrophy and its relationship with heart disease.
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Affiliation(s)
- Alexander J Winkle
- The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University, Columbus, OH, USA
| | - Drew M Nassal
- The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University, Columbus, OH, USA
| | - Rebecca Shaheen
- The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University, Columbus, OH, USA
| | - Evelyn Thomas
- The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University, Columbus, OH, USA
| | - Shivangi Mohta
- The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University, Columbus, OH, USA
| | - Daniel Gratz
- The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University, Columbus, OH, USA
| | - Seth H Weinberg
- The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University, Columbus, OH, USA
| | - Thomas J Hund
- The Frick Center for Heart Failure and Arrhythmia, The Dorothy M. Davis Heart and Lung Research Institute, the Ohio State University Wexner Medical Center, Columbus, OH, USA.,Department of Biomedical Engineering, College of Engineering, the Ohio State University, Columbus, OH, USA.,Department of Internal Medicine, College of Medicine, the Ohio State University Wexner Medical Center, Columbus, OH, USA
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Multisite phosphorylation of the cardiac ryanodine receptor: a random or coordinated event? Pflugers Arch 2020; 472:1793-1807. [PMID: 33078311 DOI: 10.1007/s00424-020-02473-3] [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: 07/09/2020] [Revised: 09/03/2020] [Accepted: 10/02/2020] [Indexed: 10/23/2022]
Abstract
Many proteins are phosphorylated at more than one phosphorylation site to achieve precise tuning of protein function and/or integrate a multitude of signals into the activity of one protein. Increasing the number of phosphorylation sites significantly broadens the complexity of molecular mechanisms involved in processing multiple phosphorylation sites by one or more distinct kinases. The cardiac ryanodine receptor (RYR2) is a well-established multiple phospho-target of kinases activated in response to β-adrenergic stimulation because this Ca2+ channel is a critical component of Ca2+ handling machinery which is responsible for β-adrenergic enhancement of cardiac contractility. Our review presents a selective overview of the extensive, often conflicting, literature which focuses on identifying reliable lines of evidence to establish if multiple RYR2 phosphorylation is achieved randomly or in a specific sequence, and whether phosphorylation at individual sites is functionally specific and additive or similar and can therefore be substituted.
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Zhang P. CaMKII: The molecular villain that aggravates cardiovascular disease. Exp Ther Med 2017; 13:815-820. [PMID: 28450904 PMCID: PMC5403363 DOI: 10.3892/etm.2017.4034] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 01/05/2017] [Indexed: 01/03/2023] Open
Abstract
Pathological remodeling of the myocardium is an integral part of the events that lead to heart failure (HF), which involves altered gene expression, disturbed signaling pathways and altered Ca2+ homeostasis and the players involved in this process. Of particular interest is the chronic activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) isoforms in heart, which further aggravate the injury to myocardium. Expression and activity of CaMKII have been found to be elevated in various conditions of stressed myocardium and in different heart diseases in both animal models as well as heart patients. CaMKII is a signaling molecule that regulates many cellular pathways by phosphorylating several proteins involved in excitation-contraction coupling and relaxation events in heart, cardiomyocyte apoptosis, transcriptional activation of genes related to cardiac hypertrophy, inflammation, and arrhythmias. CaMKII is activated by reactive oxygen species (ROS), which are elevated under conditions of ischemia-reperfusion injury and in a cyclical manner, CaMKII in turn elevates ROS production. Both ROS and activated CaMKII increase Ca-induced Ca release from sarcoplasmic reticulum, which leads to cardiomyocyte membrane depolarization and arrhythmias. These CaMKII-mediated changes in heart ultimately culminate in dysfunctional myocardium and HF. Genetic studies in animal models clearly demonstrated that inactivation of CaMKII is protective against a variety of stress induced cardiac dysfunctions. Despite significant leaps in understanding the structural details of CaMKII, which is a very complicated and multimeric modular protein, currently there is no specific and potent inhibitor of this enzyme, that can be developed for therapeutic purposes.
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Affiliation(s)
- Peiying Zhang
- Department of Cardiology, Xuzhou Central Hospital, The Affiliated Xuzhou Hospital of Medical College of Southeast University, Xuzhou, Jiangsu 221009, P.R. China
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Fu Y, Shaw SA, Naami R, Vuong CL, Basheer WA, Guo X, Hong T. Isoproterenol Promotes Rapid Ryanodine Receptor Movement to Bridging Integrator 1 (BIN1)-Organized Dyads. Circulation 2016; 133:388-97. [PMID: 26733606 DOI: 10.1161/circulationaha.115.018535] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/21/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND The key pathophysiology of human acquired heart failure is impaired calcium transient, which is initiated at dyads consisting of ryanodine receptors (RyRs) at sarcoplasmic reticulum apposing CaV1.2 channels at t-tubules. Sympathetic tone regulates myocardial calcium transients through β-adrenergic receptor (β-AR)-mediated phosphorylation of dyadic proteins. Phosphorylated RyRs (P-RyR) have increased calcium sensitivity and open probability, amplifying calcium transient at a cost of receptor instability. Given that bridging integrator 1 (BIN1) organizes t-tubule microfolds and facilitates CaV1.2 delivery, we explored whether β-AR-regulated RyRs are also affected by BIN1. METHODS AND RESULTS Isolated adult mouse hearts or cardiomyocytes were perfused for 5 minutes with the β-AR agonist isoproterenol (1 µmol/L) or the blockers CGP+ICI (baseline). Using biochemistry and superresolution fluorescent imaging, we identified that BIN1 clusters P-RyR and CaV1.2. Acute β-AR activation increases coimmunoprecipitation between P-RyR and cardiac spliced BIN1+13+17 (with exons 13 and 17). Isoproterenol redistributes BIN1 to t-tubules, recruiting P-RyRs and improving the calcium transient. In cardiac-specific Bin1 heterozygote mice, isoproterenol fails to concentrate BIN1 to t-tubules, impairing P-RyR recruitment. The resultant accumulation of uncoupled P-RyRs increases the incidence of spontaneous calcium release. In human hearts with end-stage ischemic cardiomyopathy, we find that BIN1 is also 50% reduced, with diminished P-RyR association with BIN1. CONCLUSIONS On β-AR activation, reorganization of BIN1-induced microdomains recruits P-RyR into dyads, increasing the calcium transient while preserving electric stability. When BIN1 is reduced as in human acquired heart failure, acute stress impairs microdomain formation, limiting contractility and promoting arrhythmias.
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Affiliation(s)
- Ying Fu
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Seiji A Shaw
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Robert Naami
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Caresse L Vuong
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Wassim A Basheer
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - Xiuqing Guo
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.)
| | - TingTing Hong
- From Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA (Y.F., S.A.S., R.N., C.L.V., W.A.B., T.H.); Institute for Translational Genomics and Population Sciences, Department of Pediatrics, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA (X.G.); and Departments of Medicine, Cedars-Sinai Medical Center and UCLA, Los Angeles, CA (T.H.).
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Grimm M, Ling H, Willeford A, Pereira L, Gray CBB, Erickson JR, Sarma S, Respress JL, Wehrens XHT, Bers DM, Brown JH. CaMKIIδ mediates β-adrenergic effects on RyR2 phosphorylation and SR Ca(2+) leak and the pathophysiological response to chronic β-adrenergic stimulation. J Mol Cell Cardiol 2015; 85:282-91. [PMID: 26080362 PMCID: PMC4530053 DOI: 10.1016/j.yjmcc.2015.06.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 06/06/2015] [Accepted: 06/09/2015] [Indexed: 12/21/2022]
Abstract
Chronic activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) has been implicated in the deleterious effects of β-adrenergic receptor (β-AR) signaling on the heart, in part, by enhancing RyR2-mediated sarcoplasmic reticulum (SR) Ca(2+) leak. We used CaMKIIδ knockout (CaMKIIδ-KO) mice and knock-in mice with an inactivated CaMKII site S2814 on the ryanodine receptor type 2 (S2814A) to investigate the involvement of these processes in β-AR signaling and cardiac remodeling. Langendorff-perfused hearts from CaMKIIδ-KO mice showed inotropic and chronotropic responses to isoproterenol (ISO) that were similar to those of wild type (WT) mice; however, in CaMKIIδ-KO mice, CaMKII phosphorylation of phospholamban and RyR2 was decreased and isolated myocytes from CaMKIIδ-KO mice had reduced SR Ca(2+) leak in response to isoproterenol (ISO). Chronic catecholamine stress with ISO induced comparable increases in relative heart weight and other measures of hypertrophy from day 9 through week 4 in WT and CaMKIIδ-KO mice, but the development of cardiac fibrosis was prevented in CaMKIIδ-KO animals. A 4-week challenge with ISO resulted in reduced cardiac function and pulmonary congestion in WT, but not in CaMKIIδ-KO or S2814A mice, implicating CaMKIIδ-dependent phosphorylation of RyR2-S2814 in the cardiomyopathy, independent of hypertrophy, induced by prolonged β-AR stimulation.
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Affiliation(s)
- Michael Grimm
- Department of Pharmacology, University of California, San Diego, CA, USA
| | - Haiyun Ling
- Department of Pharmacology, University of California, San Diego, CA, USA
| | - Andrew Willeford
- Department of Pharmacology, University of California, San Diego, CA, USA
| | - Laetitia Pereira
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Charles B B Gray
- Department of Pharmacology, University of California, San Diego, CA, USA
| | | | - Satyam Sarma
- Department of Molecular Physiology & Biophysics, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Jonathan L Respress
- Department of Molecular Physiology & Biophysics, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Xander H T Wehrens
- Department of Molecular Physiology & Biophysics, Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Joan Heller Brown
- Department of Pharmacology, University of California, San Diego, CA, USA.
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Duan DD. Calm down when the heart is stressed: Inhibiting calmodulin-dependent protein kinase II for antiarrhythmias. Trends Cardiovasc Med 2015; 25:398-400. [PMID: 25910598 DOI: 10.1016/j.tcm.2015.01.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 01/31/2015] [Indexed: 12/27/2022]
Abstract
Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) plays a pivotal role in many regulatory processes of cellular functions ranging from membrane potentials and electric-contraction (E-C) coupling to mitochondrial integrity and survival of cardiomyocytes. The review article by Hund and Mohler in this issue of Trends in Cardiovascular Medicine highlights the importance of the elevated CaMKII signaling pathways under stressed conditions such as myocardial hypertrophy and ischemia in the detrimental remodeling of ion channels and in the genesis of cardiac arrhythmias. Down-regulation of the elevated CaMKII is now emerging as a powerful therapeutic strategy for the treatment of cardiac arrhythmias and other forms of heart disease such as hypertrophic and ischemic heart failure. The development of new specific and effective CaMKII inhibitors as therapeutic agents for cardiac arrhythmias is challenged by the tremendous complexity of CaMKII expression and distribution of multi isoforms, as well as the multitude of downstream targets in the CaMKII signaling pathways and regulatory processes. A systematic understanding of the structure and regulation of the CaMKII signaling and functional network under the scope of genome and phenome may improve and extend our knowledge about the role of CaMKII in cardiac health and disease and accelerate the discovery of new CaMKII inhibitors that target not only the ATP-binding site but also the regulation sites in the CaMKII signaling and functional network.
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Affiliation(s)
- Dayue Darrel Duan
- The Laboratory of Cardiovascular Phenomics, Center for Molecular Medicine, School of Medicine University of Nevada, Reno, NV; Department of Pharmacology, School of Medicine University of Nevada, Reno, NV.
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Westenbrink BD, Ling H, Divakaruni AS, Gray CBB, Zambon AC, Dalton ND, Peterson KL, Gu Y, Matkovich SJ, Murphy AN, Miyamoto S, Dorn GW, Heller Brown J. Mitochondrial reprogramming induced by CaMKIIδ mediates hypertrophy decompensation. Circ Res 2015; 116:e28-39. [PMID: 25605649 DOI: 10.1161/circresaha.116.304682] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
RATIONALE Sustained activation of Gαq transgenic (Gq) signaling during pressure overload causes cardiac hypertrophy that ultimately progresses to dilated cardiomyopathy. The molecular events that drive hypertrophy decompensation are incompletely understood. Ca(2+)/calmodulin-dependent protein kinase II δ (CaMKIIδ) is activated downstream of Gq, and overexpression of Gq and CaMKIIδ recapitulates hypertrophy decompensation. OBJECTIVE To determine whether CaMKIIδ contributes to hypertrophy decompensation provoked by Gq. METHODS AND RESULTS Compared with Gq mice, compound Gq/CaMKIIδ knockout mice developed a similar degree of cardiac hypertrophy but exhibited significantly improved left ventricular function, less cardiac fibrosis and cardiomyocyte apoptosis, and fewer ventricular arrhythmias. Markers of oxidative stress were elevated in mitochondria from Gq versus wild-type mice and respiratory rates were lower; these changes in mitochondrial function were restored by CaMKIIδ deletion. Gq-mediated increases in mitochondrial oxidative stress, compromised membrane potential, and cell death were recapitulated in neonatal rat ventricular myocytes infected with constitutively active Gq and attenuated by CaMKII inhibition. Deep RNA sequencing revealed altered expression of 41 mitochondrial genes in Gq hearts, with normalization of ≈40% of these genes by CaMKIIδ deletion. Uncoupling protein 3 was markedly downregulated in Gq or by Gq expression in neonatal rat ventricular myocytes and reversed by CaMKIIδ deletion or inhibition, as was peroxisome proliferator-activated receptor α. The protective effects of CaMKIIδ inhibition on reactive oxygen species generation and cell death were abrogated by knock down of uncoupling protein 3. Conversely, restoration of uncoupling protein 3 expression attenuated reactive oxygen species generation and cell death induced by CaMKIIδ. Our in vivo studies further demonstrated that pressure overload induced decreases in peroxisome proliferator-activated receptor α and uncoupling protein 3, increases in mitochondrial protein oxidation, and hypertrophy decompensation, which were attenuated by CaMKIIδ deletion. CONCLUSIONS Mitochondrial gene reprogramming induced by CaMKIIδ emerges as an important mechanism contributing to mitotoxicity in decompensating hypertrophy.
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Affiliation(s)
- B Daan Westenbrink
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Haiyun Ling
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Ajit S Divakaruni
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Charles B B Gray
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Alexander C Zambon
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Nancy D Dalton
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Kirk L Peterson
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Yusu Gu
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Scot J Matkovich
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Anne N Murphy
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Shigeki Miyamoto
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Gerald W Dorn
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
| | - Joan Heller Brown
- From the Department of Pharmacology (B.D.W., H.L., A.S.D., C.B.B.G., A.C.Z., A.N.M., J.H.B.), Department of Medicine (N.D.D., K.L.P., Y.G.), and Biomedical Sciences Graduate Program (C.B.B.G.), University of California San Diego; School of Internal Medicine, Center for Pharmacogenomics, Washington University School of Medicine, St. Louis, MO (S.J.M., G.W.D.); Department of Cardiology, University Medical Center Groningen, Unversity of Groningen, Groningen, The Netherlands (B.D.W.)
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11
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Qu Z. Network Dynamics in Cardiac Electrophysiology. SYSTEMS BIOLOGY OF METABOLIC AND SIGNALING NETWORKS 2014. [DOI: 10.1007/978-3-642-38505-6_10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Westenbrink BD, Edwards AG, McCulloch AD, Brown JH. The promise of CaMKII inhibition for heart disease: preventing heart failure and arrhythmias. Expert Opin Ther Targets 2013; 17:889-903. [PMID: 23789646 DOI: 10.1517/14728222.2013.809064] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Calcium-calmodulin-dependent protein kinase II (CaMKII) has emerged as a central mediator of cardiac stress responses which may serve several critical roles in the regulation of cardiac rhythm, cardiac contractility and growth. Sustained and excessive activation of CaMKII during cardiac disease has, however, been linked to arrhythmias, and maladaptive cardiac remodeling, eventually leading to heart failure (HF) and sudden cardiac death. AREAS COVERED In the current review, the authors describe the unique structural and biochemical properties of CaMKII and focus on its physiological effects in cardiomyocytes. Furthermore, they provide evidence for a role of CaMKII in cardiac pathologies, including arrhythmogenesis, myocardial ischemia and HF development. The authors conclude by discussing the potential for CaMKII as a target for inhibition in heart disease. EXPERT OPINION CaMKII provides a promising nodal point for intervention that may allow simultaneous prevention of HF progression and development of arrhythmias. For future studies and drug development there is a strong rationale for the development of more specific CaMKII inhibitors. In addition, an improved understanding of the differential roles of CaMKII subtypes is required.
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Affiliation(s)
- B Daan Westenbrink
- University of California, Department of Pharmacology, San Diego, La Jolla, CA, USA
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Stokke MK, Tovsrud N, Louch WE, Øyehaug L, Hougen K, Sejersted OM, Swift F, Sjaastad I. I(CaL) inhibition prevents arrhythmogenic Ca(2+) waves caused by abnormal Ca(2+) sensitivity of RyR or SR Ca(2+) accumulation. Cardiovasc Res 2013; 98:315-25. [PMID: 23417043 DOI: 10.1093/cvr/cvt037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIMS Arrhythmogenic Ca(2+) waves result from uncontrolled Ca(2+) release from the sarcoplasmic reticulum (SR) that occurs with increased Ca(2+) sensitivity of the ryanodine receptor (RyR) or excessive Ca(2+) accumulation during β-adrenergic stimulation. We hypothesized that inhibition of the L-type Ca(2+) current (I(CaL)) could prevent such Ca(2+) waves in both situations. METHODS AND RESULTS Ca(2+) waves were induced in mouse left ventricular cardiomyocytes by isoproterenol combined with caffeine to increase RyR Ca(2+) sensitivity. I(CaL) inhibition by verapamil (0.5 µM) reduced Ca(2+) wave probability in cardiomyocytes during electrostimulation, and during a 10 s rest period after ceasing stimulation. A separate type of Ca(2+) release events occurred during the decay phase of the Ca(2+) transient and was not prevented by verapamil. Verapamil decreased Ca(2+) spark frequency, but not in permeabilized cells, indicating that this was not due to direct effects on RyR. The antiarrhythmic effect of verapamil was due to reduced SR Ca(2+) content following I(CaL) inhibition. Computational modelling supported that the level of I(CaL) inhibition obtained experimentally was sufficient to reduce the SR Ca(2+) content. Ca(2+) wave prevention through reduced SR Ca(2+) content was also effective in heterozygous ankyrin B knockout mice with excessive SR Ca(2+) accumulation during β-adrenergic stimulation. CONCLUSION I(CaL) inhibition prevents diastolic Ca(2+) waves caused by increased Ca(2+) sensitivity of RyR or excessive SR Ca(2+) accumulation during β-adrenergic stimulation. In contrast, unstimulated early Ca(2+) release during the decay of the Ca(2+) transient is not prevented, and merits further study to understand the full antiarrhythmic potential of I(CaL) inhibition.
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Affiliation(s)
- Mathis K Stokke
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway.
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Zhang X, Szeto C, Gao E, Tang M, Jin J, Fu Q, Makarewich C, Ai X, Li Y, Tang A, Wang J, Gao H, Wang F, Ge XJ, Kunapuli SP, Zhou L, Zeng C, Xiang KY, Chen X. Cardiotoxic and cardioprotective features of chronic β-adrenergic signaling. Circ Res 2012; 112:498-509. [PMID: 23104882 DOI: 10.1161/circresaha.112.273896] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE In the failing heart, persistent β-adrenergic receptor activation is thought to induce myocyte death by protein kinase A (PKA)-dependent and PKA-independent activation of calcium/calmodulin-dependent kinase II. β-adrenergic signaling pathways also are capable of activating cardioprotective mechanisms. OBJECTIVE This study used a novel PKA inhibitor peptide to inhibit PKA activity to test the hypothesis that β-adrenergic receptor signaling causes cell death through PKA-dependent pathways and cardioprotection through PKA-independent pathways. METHODS AND RESULTS In PKA inhibitor peptide transgenic mice, chronic isoproterenol failed to induce cardiac hypertrophy, fibrosis, and myocyte apoptosis, and decreased cardiac function. In cultured adult feline ventricular myocytes, PKA inhibition protected myocytes from death induced by β1-adrenergic receptor agonists by preventing cytosolic and sarcoplasmic reticulum Ca(2+) overload and calcium/calmodulin-dependent kinase II activation. PKA inhibition revealed a cardioprotective role of β-adrenergic signaling via cAMP/exchange protein directly activated by cAMP/Rap1/Rac/extracellular signal-regulated kinase pathway. Selective PKA inhibition causes protection in the heart after myocardial infarction that was superior to β-blocker therapy. CONCLUSIONS These results suggest that selective block of PKA could be a novel heart failure therapy.
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Affiliation(s)
- Xiaoying Zhang
- Cardiovascular Research Center, Department of Physiology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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15
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Vahedi F, Odenstedt J, Hartford M, Gilljam T, Bergfeldt L. Vectorcardiography analysis of the repolarization response to pharmacologically induced autonomic nervous system modulation in healthy subjects. J Appl Physiol (1985) 2012; 113:368-76. [PMID: 22582212 DOI: 10.1152/japplphysiol.01190.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Autonomic nervous system activity is essential for regulation of ventricular repolarization (VR) and plays an important role in several arrhythmogenic conditions. This study in 31 healthy adult subjects (16 men, 15 women) evaluated the VR response to pharmacologically modulated autonomic nervous system activity applying vectorcardiography (VCG) analysis. During continuous VCG recording, 0.01-0.1 μg·kg(-1)·min(-1) isoprenaline (Iso) was infused at an increasing flow rate until three targeted heart rates (HR) were reached. After Iso washout, one intravenous bolus of 0.04 mg/kg atropine was given followed by an intravenous bolus of 0.2 mg/kg propranolol. A 5-min steady-state VCG recording was analyzed for each of the seven phases (including baseline 1 and 2). Furthermore, during the first 4 min following atropine, six periods of 10-s VCG were selected for subanalysis to evaluate the time course of change. The analysis included QRS, QT, and T-peak to T-end intervals, measures of the QRS and T vectors and their relation, as well as T-loop morphology parameters. By increasing HR, Iso infusion decreased HR dependent parameters reflecting total heterogeneity of VR (T area) and action potential morphology (ventricular gradient). In contrast, Iso prolonged QT HR corrected according to Bazett and increased the T-peak to T-end-to-QT ratio to levels observed in arrhythmogenic conditions. HR acceleration after atropine was accompanied by a transient paradoxical QT prolongation and delayed HR adaptation of T area and ventricular gradient. In addition to the expected HR adaptation, the VR response to β-adrenoceptor stimulation with Iso and to muscarinic receptor blockade with atropine thus included alterations previously observed in congenital and acquired long QT syndromes, demonstrating substantial overlap between physiological and pathophysiological electrophysiology.
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Affiliation(s)
- Farzad Vahedi
- Department of Molecular and Clinical Medicine/Cardiology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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