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Terrar DA. Timing mechanisms to control heart rhythm and initiate arrhythmias: roles for intracellular organelles, signalling pathways and subsarcolemmal Ca 2. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220170. [PMID: 37122228 PMCID: PMC10150226 DOI: 10.1098/rstb.2022.0170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Rhythms of electrical activity in all regions of the heart can be influenced by a variety of intracellular membrane bound organelles. This is true both for normal pacemaker activity and for abnormal rhythms including those caused by early and delayed afterdepolarizations under pathological conditions. The influence of the sarcoplasmic reticulum (SR) on cardiac electrical activity is widely recognized, but other intracellular organelles including lysosomes and mitochondria also contribute. Intracellular organelles can provide a timing mechanism (such as an SR clock driven by cyclic uptake and release of Ca2+, with an important influence of intraluminal Ca2+), and/or can act as a Ca2+ store involved in signalling mechanisms. Ca2+ plays many diverse roles including carrying electric current, driving electrogenic sodium-calcium exchange (NCX) particularly when Ca2+ is extruded across the surface membrane causing depolarization, and activation of enzymes which target organelles and surface membrane proteins. Heart function is also influenced by Ca2+ mobilizing agents (cADP-ribose, nicotinic acid adenine dinucleotide phosphate and inositol trisphosphate) acting on intracellular organelles. Lysosomal Ca2+ release exerts its effects via calcium/calmodulin-dependent protein kinase II to promote SR Ca2+ uptake, and contributes to arrhythmias resulting from excessive beta-adrenoceptor stimulation. A separate arrhythmogenic mechanism involves lysosomes, mitochondria and SR. Interacting intracellular organelles, therefore, have profound effects on heart rhythms and NCX plays a central role. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- Derek A Terrar
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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2
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Kanaporis G, Blatter LA. Activation of small conductance Ca 2+ -activated K + channels suppresses Ca 2+ transient and action potential alternans in ventricular myocytes. J Physiol 2023; 601:51-67. [PMID: 36426548 PMCID: PMC9878619 DOI: 10.1113/jp283870] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/22/2022] [Indexed: 11/27/2022] Open
Abstract
At the cellular level, cardiac alternans is observed as beat-to-beat alternations in contraction strength, action potential (AP) morphology and Ca2+ transient (CaT) amplitude, and is a risk factor for cardiac arrhythmia. The (patho)physiological roles of small conductance Ca2+ -activated K+ (SK) channels in ventricles are poorly understood. We tested the hypothesis that in single rabbit ventricular myocytes pharmacological modulation of SK channels plays a causative role for the development of pacing-induced CaT and AP duration (APD) alternans. SK channel blockers (apamin, UCL1684) had only a minor effect on AP repolarization. However, SK channel activation by NS309 resulted in significant APD shortening, demonstrating that functional SK channels are well expressed in ventricular myocytes. The effects of NS309 were prevented or reversed by apamin and UCL1684, indicating that NS309 acted on SK channels. SK channel activation abolished or reduced the degree of pacing-induced CaT and APD alternans. Inhibition of KV 7.1 (with HMR1556) and KV 11.1 (with E4031) channels was used to mimic conditions of long QT syndromes type-1 and type-2, respectively. Both HMR1556 and E4031 enhanced CaT alternans that was prevented by SK channel activation. In AP voltage-clamped cells the SK channel activator had no effect on CaT alternans, confirming that suppression of CaT alternans was caused by APD shortening. APD shortening contributed to protection from alternans by lowering sarcoplasmic reticulum Ca2+ content and curtailing Ca2+ release. The data suggest that SK activation could be a potential intervention to avert development of alternans with important ramifications for arrhythmia prevention and therapy for patients with long QT syndrome. KEY POINTS: At the cellular level, cardiac alternans is observed as beat-to-beat alternations in contraction strength, action potential (AP) morphology and intracellular Ca2+ release amplitude, and is a risk factor for cardiac arrhythmia. The (patho)physiological roles of small conductance Ca2+ -activated K+ (SK) channels in ventricles are poorly understood. We investigated whether pharmacological modulation of SK channels affects the development of cardiac alternans in normal ventricular cells and in cells with drug-induced long QT syndrome (LQTS). While SK channel blockers have only a minor effect on AP morphology, their activation leads to AP shortening and abolishes or reduces the degree of pacing-induced Ca2+ and AP alternans. AP shortening contributed to protection against alternans by lowering sarcoplasmic reticulum Ca2+ content and curtailing Ca2+ release. The data suggest SK activation as a potential intervention to avert the development of alternans with important ramifications for arrhythmia prevention for patients with LQTS.
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Affiliation(s)
- Giedrius Kanaporis
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, Illinois, USA
| | - Lothar A Blatter
- Department of Physiology & Biophysics, Rush University Medical Center, Chicago, Illinois, USA
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3
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Rotors anchored by refractory islands drive torsades de pointes in an experimental model of electrical storm. Heart Rhythm 2022; 19:318-329. [PMID: 34678525 PMCID: PMC8810573 DOI: 10.1016/j.hrthm.2021.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND Electrical storm (ES) is a life-threatening emergency in patients at high risk of ventricular tachycardia/ventricular fibrillation (VF), but the pathophysiology and molecular basis are poorly understood. OBJECTIVE The purpose of this study was to explore the electrophysiological substrate for experimental ES. METHODS A model was created by inducing chronic complete atrioventricular block in defibrillator-implanted rabbits, which recapitulates QT prolongation, torsades des pointes (TdP), and VF episodes. RESULTS Optical mapping revealed island-like regions with action potential duration (APD) prolongation in the left ventricle, leading to increased spatial APD dispersion, in rabbits with ES (defined as ≥3 VF episodes/24 h). The maximum APD and its dispersion correlated with the total number of VF episodes in vivo. TdP was initiated by an ectopic beat that failed to enter the island and formed a reentrant wave and perpetuated by rotors whose centers swirled in the periphery of the island. Epinephrine exacerbated the island by prolonging APD and enhancing APD dispersion, which was less evident after late Na+ current blockade with 10 μM ranolazine. Nonsustained ventricular tachycardia in a non-ES rabbit heart with homogeneous APD prolongation resulted from multiple foci with an electrocardiographic morphology different from TdP driven by drifting rotors in ES rabbit hearts. The neuronal Na+-channel subunit NaV1.8 was upregulated in ES rabbit left ventricular tissues and expressed within the myocardium corresponding to the island location in optically mapped ES rabbit hearts. The NaV1.8 blocker A-803467 (10 mg/kg, intravenously) attenuated QT prolongation and suppressed epinephrine-evoked TdP. CONCLUSION A tissue island with enhanced refractoriness contributes to the generation of drifting rotors that underlies ES in this model. NaV1.8-mediated late Na+ current merits further investigation as a contributor to the substrate for ES.
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Zong P, Lin Q, Feng J, Yue L. A Systemic Review of the Integral Role of TRPM2 in Ischemic Stroke: From Upstream Risk Factors to Ultimate Neuronal Death. Cells 2022; 11:491. [PMID: 35159300 PMCID: PMC8834171 DOI: 10.3390/cells11030491] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 01/26/2022] [Accepted: 01/29/2022] [Indexed: 02/04/2023] Open
Abstract
Ischemic stroke causes a heavy health burden worldwide, with over 10 million new cases every year. Despite the high prevalence and mortality rate of ischemic stroke, the underlying molecular mechanisms for the common etiological factors of ischemic stroke and ischemic stroke itself remain unclear, which results in insufficient preventive strategies and ineffective treatments for this devastating disease. In this review, we demonstrate that transient receptor potential cation channel, subfamily M, member 2 (TRPM2), a non-selective ion channel activated by oxidative stress, is actively involved in all the important steps in the etiology and pathology of ischemic stroke. TRPM2 could be a promising target in screening more effective prophylactic strategies and therapeutic medications for ischemic stroke.
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Affiliation(s)
- Pengyu Zong
- Department of Cell Biology, Calhoun Cardiology Center, University of Connecticut School of Medicine (UConnHealth), Farmington, CT 06030, USA; (P.Z.); (J.F.)
| | - Qiaoshan Lin
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA;
| | - Jianlin Feng
- Department of Cell Biology, Calhoun Cardiology Center, University of Connecticut School of Medicine (UConnHealth), Farmington, CT 06030, USA; (P.Z.); (J.F.)
| | - Lixia Yue
- Department of Cell Biology, Calhoun Cardiology Center, University of Connecticut School of Medicine (UConnHealth), Farmington, CT 06030, USA; (P.Z.); (J.F.)
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Angelini M, Pezhouman A, Savalli N, Chang MG, Steccanella F, Scranton K, Calmettes G, Ottolia M, Pantazis A, Karagueuzian HS, Weiss JN, Olcese R. Suppression of ventricular arrhythmias by targeting late L-type Ca2+ current. J Gen Physiol 2021; 153:212725. [PMID: 34698805 PMCID: PMC8552156 DOI: 10.1085/jgp.202012584] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/15/2021] [Accepted: 09/02/2021] [Indexed: 12/15/2022] Open
Abstract
Ventricular arrhythmias, a leading cause of sudden cardiac death, can be triggered by cardiomyocyte early afterdepolarizations (EADs). EADs can result from an abnormal late activation of L-type Ca2+ channels (LTCCs). Current LTCC blockers (class IV antiarrhythmics), while effective at suppressing EADs, block both early and late components of ICa,L, compromising inotropy. However, computational studies have recently demonstrated that selective reduction of late ICa,L (Ca2+ influx during late phases of the action potential) is sufficient to potently suppress EADs, suggesting that effective antiarrhythmic action can be achieved without blocking the early peak ICa,L, which is essential for proper excitation–contraction coupling. We tested this new strategy using a purine analogue, roscovitine, which reduces late ICa,L with minimal effect on peak current. Scaling our investigation from a human CaV1.2 channel clone to rabbit ventricular myocytes and rat and rabbit perfused hearts, we demonstrate that (1) roscovitine selectively reduces ICa,L noninactivating component in a human CaV1.2 channel clone and in ventricular myocytes native current, (2) the pharmacological reduction of late ICa,L suppresses EADs and EATs (early after Ca2+ transients) induced by oxidative stress and hypokalemia in isolated myocytes, largely preserving cell shortening and normal Ca2+ transient, and (3) late ICa,L reduction prevents/suppresses ventricular tachycardia/fibrillation in ex vivo rabbit and rat hearts subjected to hypokalemia and/or oxidative stress. These results support the value of an antiarrhythmic strategy based on the selective reduction of late ICa,L to suppress EAD-mediated arrhythmias. Antiarrhythmic therapies based on this idea would modify the gating properties of CaV1.2 channels rather than blocking their pore, largely preserving contractility.
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Affiliation(s)
- Marina Angelini
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Arash Pezhouman
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Nicoletta Savalli
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marvin G Chang
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Federica Steccanella
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Kyle Scranton
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Guillaume Calmettes
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Michela Ottolia
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,University of California, Los Angeles Cardiovascular Theme, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Antonios Pantazis
- Division of Neurobiology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.,Wallenberg Center for Molecular Medicine, Linköping University, Linköping, Sweden
| | - Hrayr S Karagueuzian
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - James N Weiss
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Riccardo Olcese
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,University of California, Los Angeles Cardiovascular Theme, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
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6
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Gonano LA, Mattiazzi A. Targeting late ICaL to close the window to ventricular arrhythmias. J Gen Physiol 2021; 153:212726. [PMID: 34699586 PMCID: PMC8552155 DOI: 10.1085/jgp.202113009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Luis A Gonano
- Centro de Investigaciones Cardiovasculares Horacio Cingolani, CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares Horacio Cingolani, CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
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7
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Different voltage dependence of I CaL blockade in nonselective I Kr blockers causes their opposite effects on early afterdepolarization in drug-induced arrhythmia. J Pharmacol Sci 2021; 147:95-103. [PMID: 34294379 DOI: 10.1016/j.jphs.2021.05.014] [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: 02/22/2021] [Revised: 05/05/2021] [Accepted: 05/24/2021] [Indexed: 11/20/2022] Open
Abstract
Several false-positive results in the human ether-à-gogo-related gene test suggest that blockers of the rapid component of delayed rectifier K+ current (IKr) do not necessarily produce drug-induced arrhythmias. Specifically, the occurrence of early afterdepolarization (EAD) differs among IKr blockers, even if the prolonged action potential duration is in the same range. To predict EAD in drug-induced arrhythmias, we proposed a prediction method based on the mechanisms underlying the difference in frequency of EAD among nonselective IKr blockers. The mechanisms were elucidated by examining how different blockade kinetics of L-type Ca2+ current (ICaL) affect the frequency of EAD, using mathematical models of human ventricular myocytes. Addition of voltage-independent ICaL blockade resulted in the suppression of EAD. However, when voltage-dependent ICaL blockade kinetics of amiodarone, bepridil, and terfenadine were incorporated into ICaL in the model, bepridil and terfenadine induced EAD more than the voltage-independent ICaL blockade, while amiodarone suppressed EAD more effectively. Opposite effects were accounted for by the difference in ICaL blockade at negatively polarized potential. EAD occurrence was found to be associated with ICaL blockade measured at -20 mV. These results suggest that voltage dependence of ICaL blockade may be useful in predicting the different risks of nonselective IKr blockers.
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8
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Hamilton S, Veress R, Belevych A, Terentyev D. The role of calcium homeostasis remodeling in inherited cardiac arrhythmia syndromes. Pflugers Arch 2021; 473:377-387. [PMID: 33404893 PMCID: PMC7940310 DOI: 10.1007/s00424-020-02505-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 02/07/2023]
Abstract
Sudden cardiac death due to malignant ventricular arrhythmias remains the major cause of mortality in the postindustrial world. Defective intracellular Ca2+ homeostasis has been well established as a key contributing factor to the enhanced propensity for arrhythmia in acquired cardiac disease, such as heart failure or diabetic cardiomyopathy. More recent advances provide a strong basis to the emerging view that hereditary cardiac arrhythmia syndromes are accompanied by maladaptive remodeling of Ca2+ homeostasis which substantially increases arrhythmic risk. This brief review will focus on functional changes in elements of Ca2+ handling machinery in cardiomyocytes that occur secondary to genetic mutations associated with catecholaminergic polymorphic ventricular tachycardia, and long QT syndrome.
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Affiliation(s)
- Shanna Hamilton
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Roland Veress
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Andriy Belevych
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Dmitry Terentyev
- Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Wexner Medical Center, The Ohio State University, Columbus, OH, USA.
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9
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Wang W, Shen W, Zhang S, Luo G, Wang K, Xu Y, Zhang H. The Role of CaMKII Overexpression and Oxidation in Atrial Fibrillation-A Simulation Study. Front Physiol 2021; 11:607809. [PMID: 33391023 PMCID: PMC7775483 DOI: 10.3389/fphys.2020.607809] [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: 09/18/2020] [Accepted: 11/19/2020] [Indexed: 11/13/2022] Open
Abstract
This simulation study aims to investigate how the Calcium/calmodulin-dependent protein kinase II (CaMKII) overexpression and oxidation would influence the cardiac electrophysiological behavior and its arrhythmogenic mechanism in atria. A new-built CaMKII oxidation module and a refitted CaMKII overexpression module were integrated into a mouse atrial cell model for analyzing cardiac electrophysiological variations in action potential (AP) characteristics and intracellular Ca2+ cycling under different conditions. Simulation results showed that CaMKII overexpression significantly increased the phosphorylation level of its downstream target proteins, resulting in prolonged AP and smaller calcium transient amplitude, and impaired the Ca2+ cycling stability. These effects were exacerbated by extra reactive oxygen species, which oxidized CaMKII and led to continuous high CaMKII activation in both systolic and diastolic phases. Intracellular Ca2+ depletion and sustained delayed afterdepolarizations (DADs) were observed under co-existing CaMKII overexpression and oxidation, which could be effectively reversed by clamping the phosphorylation level of ryanodine receptor (RyR). We also found that the stability of RyR release highly depended on a delicate balance between the level of RyR phosphorylation and sarcoplasmic reticulum Ca2+ concentration, which was closely related to the genesis of DADs. We concluded that the CaMKII overexpression and oxidation have a synergistic role in increasing the activity of CaMKII, and the unstable RyR may be the key downstream target in the CaMKII arrhythmogenic mechanism. Our simulation provides detailed mechanistic insights into the arrhythmogenic effect of CaMKII overexpression and oxidation, which suggests CaMKII as a promising target in the therapy of atrial fibrillation.
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Affiliation(s)
- Wei Wang
- Shenzhen Key Laboratory of Visual Object Detection and Recognition, Harbin Institute of Technology, Shenzhen, China.,Peng Cheng Lab, Shenzhen, China
| | - Weijian Shen
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Shanzhuo Zhang
- Department of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Gongning Luo
- Department of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Kuanquan Wang
- Department of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Yong Xu
- Shenzhen Key Laboratory of Visual Object Detection and Recognition, Harbin Institute of Technology, Shenzhen, China
| | - Henggui Zhang
- Peng Cheng Lab, Shenzhen, China.,Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
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10
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Role of Oxidation-Dependent CaMKII Activation in the Genesis of Abnormal Action Potentials in Atrial Cardiomyocytes: A Simulation Study. BIOMED RESEARCH INTERNATIONAL 2020; 2020:1597012. [PMID: 32685443 PMCID: PMC7327560 DOI: 10.1155/2020/1597012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 05/20/2020] [Accepted: 06/02/2020] [Indexed: 01/04/2023]
Abstract
Atrial fibrillation is a common cardiac arrhythmia with an increasing incidence rate. Particularly for the aging population, understanding the underlying mechanisms of atrial arrhythmia is important in designing clinical treatment. Recently, experiments have shown that atrial arrhythmia is associated with oxidative stress. In this study, an atrial cell model including oxidative-dependent Ca2+/calmodulin- (CaM-) dependent protein kinase II (CaMKII) activation was developed to explore the intrinsic mechanisms of atrial arrhythmia induced by oxidative stress. The simulation results showed that oxidative stress caused early afterdepolarizations (EADs) of action potentials by altering the dynamics of transmembrane currents and intracellular calcium cycling. Oxidative stress gradually elevated the concentration of calcium ions in the cytoplasm by enhancing the L-type Ca2+ current and sarcoplasmic reticulum (SR) calcium release. Owing to increased intracellular calcium concentration, the inward Na+/Ca2+ exchange current was elevated which slowed down the repolarization of the action potential. Thus, the action potential was prolonged and the L-type Ca2+ current was reactivated, resulting in the genesis of EAD. Furthermore, based on the atrial single-cell model, a two-dimensional (2D) ideal tissue model was developed to explore the effect of oxidative stress on the electrical excitation wave conduction in 2D tissue. Simulation results demonstrated that, under oxidative stress conditions, EAD hindered the conduction of electrical excitation and caused an unstable spiral wave, which could disrupt normal cardiac rhythm and cause atrial arrhythmia. This study showed the effects of excess reactive oxygen species on calcium cycling and action potential in atrial myocytes and provided insights regarding atrial arrhythmia induced by oxidative stress.
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11
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Ottesen AH, Carlson CR, Eken OS, Sadredini M, Myhre PL, Shen X, Dalhus B, Laver DR, Lunde PK, Kurola J, Lunde M, Hoff JE, Godang K, Sjaastad I, Pettilä V, Stridsberg M, Lehnart SE, Edwards AG, Lunde IG, Omland T, Stokke MK, Christensen G, Røsjø H, Louch WE. Secretoneurin Is an Endogenous Calcium/Calmodulin-Dependent Protein Kinase II Inhibitor That Attenuates Ca 2+-Dependent Arrhythmia. Circ Arrhythm Electrophysiol 2020; 12:e007045. [PMID: 30943765 DOI: 10.1161/circep.118.007045] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Circulating SN (secretoneurin) concentrations are increased in patients with myocardial dysfunction and predict poor outcome. Because SN inhibits CaMKIIδ (Ca2+/calmodulin-dependent protein kinase IIδ) activity, we hypothesized that upregulation of SN in patients protects against cardiomyocyte mechanisms of arrhythmia. METHODS Circulating levels of SN and other biomarkers were assessed in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT; n=8) and in resuscitated patients after ventricular arrhythmia-induced cardiac arrest (n=155). In vivo effects of SN were investigated in CPVT mice (RyR2 [ryanodine receptor 2]-R2474S) using adeno-associated virus-9-induced overexpression. Interactions between SN and CaMKIIδ were mapped using pull-down experiments, mutagenesis, ELISA, and structural homology modeling. Ex vivo actions were tested in Langendorff hearts and effects on Ca2+ homeostasis examined by fluorescence (fluo-4) and patch-clamp recordings in isolated cardiomyocytes. RESULTS SN levels were elevated in patients with CPVT and following ventricular arrhythmia-induced cardiac arrest. In contrast to NT-proBNP (N-terminal pro-B-type natriuretic peptide) and hs-TnT (high-sensitivity troponin T), circulating SN levels declined after resuscitation, as the risk of a new arrhythmia waned. Myocardial pro-SN expression was also increased in CPVT mice, and further adeno-associated virus-9-induced overexpression of SN attenuated arrhythmic induction during stress testing with isoproterenol. Mechanistic studies mapped SN binding to the substrate binding site in the catalytic region of CaMKIIδ. Accordingly, SN attenuated isoproterenol induced autophosphorylation of Thr287-CaMKIIδ in Langendorff hearts and inhibited CaMKIIδ-dependent RyR phosphorylation. In line with CaMKIIδ and RyR inhibition, SN treatment decreased Ca2+ spark frequency and dimensions in cardiomyocytes during isoproterenol challenge, and reduced the incidence of Ca2+ waves, delayed afterdepolarizations, and spontaneous action potentials. SN treatment also lowered the incidence of early afterdepolarizations during isoproterenol; an effect paralleled by reduced magnitude of L-type Ca2+ current. CONCLUSIONS SN production is upregulated in conditions with cardiomyocyte Ca2+ dysregulation and offers compensatory protection against cardiomyocyte mechanisms of arrhythmia, which may underlie its putative use as a biomarker in at-risk patients.
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Affiliation(s)
- Anett H Ottesen
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.).,Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Cathrine R Carlson
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Olav Søvik Eken
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Mani Sadredini
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Peder L Myhre
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.).,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Xin Shen
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Bjørn Dalhus
- Department for Microbiology, Clinic for Laboratory Medicine (B.D.), Oslo University Hospital, Norway.,Department for Medical Biochemistry, Institute for Clinical Medicine (B.D.), University of Oslo, Norway
| | - Derek R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (D.R.L.)
| | - Per Kristian Lunde
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Jouni Kurola
- Division of Intensive Care Medicine, Kuopio University Hospital, Finland (J.K.)
| | - Marianne Lunde
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Jon Erik Hoff
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.)
| | - Kristin Godang
- Section of Specialized Endocrinology, Department of Endocrinology (K.G.), Oslo University Hospital, Norway
| | - Ivar Sjaastad
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway.,K.G. Jebsen Center for Cardiac Research (I.S., G.C., W.E.L.), University of Oslo, Norway
| | - Ville Pettilä
- Division of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki & Helsinki University Hospital, Finland (V.P.)
| | - Mats Stridsberg
- Department of Medical Sciences, Uppsala University, Sweden (M. Stridsberg)
| | - Stephan E Lehnart
- Heart Research Center Goettingen, University Medicine Center Goettingen, Germany (S.E.L.)
| | - Andrew G Edwards
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway.,Simula Research Laboratory, Fornebu, Norway (A.G.E)
| | - Ida G Lunde
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Torbjørn Omland
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.).,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Mathis K Stokke
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - Geir Christensen
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway.,K.G. Jebsen Center for Cardiac Research (I.S., G.C., W.E.L.), University of Oslo, Norway
| | - Helge Røsjø
- Division of Medicine, Akershus University Hospital, Lørenskog, Norway (A.H.O., P.L.M., J.E.H., T.O., H.R.).,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway
| | - William E Louch
- Institute for Experimental Medical Research (A.H.O., C.R.C., O.S.E., M. Sadredini, X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., M.K.S., G.C., W.E.L.), Oslo University Hospital, Norway.,Center for Heart Failure Research (A.H.O., C.R.C., O.S.E., M. Sadredini, P.L.M., X.S., P.K.L., M.L., I.S., A.G.E., I.G.L., T.O., M.K.S., G.C., H.R., W.E.L.), University of Oslo, Norway.,K.G. Jebsen Center for Cardiac Research (I.S., G.C., W.E.L.), University of Oslo, Norway
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12
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Denham NC, Pearman CM, Caldwell JL, Madders GWP, Eisner DA, Trafford AW, Dibb KM. Calcium in the Pathophysiology of Atrial Fibrillation and Heart Failure. Front Physiol 2018; 9:1380. [PMID: 30337881 PMCID: PMC6180171 DOI: 10.3389/fphys.2018.01380] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 09/11/2018] [Indexed: 12/20/2022] Open
Abstract
Atrial fibrillation (AF) is commonly associated with heart failure. A bidirectional relationship exists between the two-AF exacerbates heart failure causing a significant increase in heart failure symptoms, admissions to hospital and cardiovascular death, while pathological remodeling of the atria as a result of heart failure increases the risk of AF. A comprehensive understanding of the pathophysiology of AF is essential if we are to break this vicious circle. In this review, the latest evidence will be presented showing a fundamental role for calcium in both the induction and maintenance of AF. After outlining atrial electrophysiology and calcium handling, the role of calcium-dependent afterdepolarizations and atrial repolarization alternans in triggering AF will be considered. The atrial response to rapid stimulation will be discussed, including the short-term protection from calcium overload in the form of calcium signaling silencing and the eventual progression to diastolic calcium leak causing afterdepolarizations and the development of an electrical substrate that perpetuates AF. The role of calcium in the bidirectional relationship between heart failure and AF will then be covered. The effects of heart failure on atrial calcium handling that promote AF will be reviewed, including effects on both atrial myocytes and the pulmonary veins, before the aspects of AF which exacerbate heart failure are discussed. Finally, the limitations of human and animal studies will be explored allowing contextualization of what are sometimes discordant results.
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Affiliation(s)
- Nathan C. Denham
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | | | | | | | | | | | - Katharine M. Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
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13
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Rat atrial engineered heart tissue: a new in vitro model to study atrial biology. Basic Res Cardiol 2018; 113:41. [DOI: 10.1007/s00395-018-0701-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 08/27/2018] [Indexed: 10/28/2022]
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14
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Duong E, Xiao J, Qi XY, Nattel S. MicroRNA-135a regulates sodium-calcium exchanger gene expression and cardiac electrical activity. Heart Rhythm 2017; 14:739-748. [PMID: 28188930 DOI: 10.1016/j.hrthm.2017.01.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Complete atrioventricular block (CAVB) causes arrhythmogenic remodeling and increases the risk of torsades de pointes arrhythmias. MicroRNAs (miRNAs) are key regulators of gene expression that contribute to cardiac remodeling. OBJECTIVE The purpose of this study was to assess miRNA changes after CAVB and identify novel candidates potentially involved in arrhythmogenic cardiac remodeling. METHODS CAVB was induced in mice via His-bundle ablation. Expression of miRNAs was evaluated by pan-miRNA microarray with quantitative polymerase chain reaction (qPCR) confirmation, on samples obtained 24 hours and 4 weeks post-CAVB. MiRNA target prediction algorithms were used to identify potential target genes. Targets confirmed by luciferase assays in HEK293 cells were followed up with overexpression studies in neonatal rat ventricular myocytes to evaluate regulation using real time- quantitative polymerase chain reaction (RT-qPCR), western blots, cell shortening measurements, and fura-2 Ca2+ fluorescence imaging. RESULTS Of >400 miRNAs assayed, only miRNA-135a (miR-135a) was altered at 24 hours, down-regulated 78% (P <.001). Algorithms predicted miR-135a regulation of the sodium-calcium exchanger type 1 (NCX1). miR-135a transfection suppressed NCX1 3'UTR reporter activity by 42% (P <.001), mRNA expression by 34% (P <.001), and protein levels by 45% (P <.001) vs noncoding miRNA control. miR-135a overexpression reduced spontaneous beating frequency of neonatal rat ventricular myocytes by 63% (P <.001) while slowing decay (by 56%, P <.05) of caffeine-induced Ca2+ transients. miR-135a also suppressed the Ca2+ loading effects of ouabain and ouabain-induced spontaneous Ca2+ release events. CONCLUSION NCX1 is negatively regulated by miR-135a, a microRNA that is down-regulated in the heart after CAVB in mice. By controlling NCX1 expression, miR-135a modulates cardiomyocyte automaticity, Ca2+ extrusion, and arrhythmogenic Ca2+ loading/spontaneous Ca2+ release events. Therefore, miR-135a may contribute to proarrhythmic remodeling after CAVB.
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Affiliation(s)
- Eric Duong
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada; Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Canada
| | - Jiening Xiao
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Canada
| | - Xiao Yan Qi
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Canada
| | - Stanley Nattel
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada; Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Canada; Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany.
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15
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Epigallocatechin-3-gallate modulates arrhythmogenic activity and calcium homeostasis of left atrium. Int J Cardiol 2017; 236:174-180. [PMID: 28117139 DOI: 10.1016/j.ijcard.2017.01.090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 11/20/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is the commonest sustained arrhythmia, and increases the risk of stroke, heart failure, and mortality. Calcium (Ca2+) overload and oxidative stress are thought to participate in the pathogenesis of AF. Epigallocatechin-3-gallate (EGCG) has an antioxidative effect and been shown to be beneficial in promoting cardiovascular health. However, it is not clear if EGCG directly modulates the electrophysiological characteristics and Ca2+ homeostasis of the left atrium (LA). METHODS AND RESULTS Conventional microelectrodes, whole-cell patch-clamp, and Fluo-3 fluorometric ratio technique were performed using the isolated rabbit LA preparations or isolated single LA cardiomyocytes before and after EGCG treatment. EGCG (0.01, 0.1, 1, and 10μM) which concentration-dependently decreased the APD20 by 13±8%, 25±5%, 31±6%, and 37±5%, APD50 by 9±8%, 22±6%, 32±7%, and 40±4%, and APD90 by 2±12%, 9±8%, 24±10%, and 34±5% in LA preparations. EGCG (0.1μM) decreased the late sodium (Na+) current, L-type Ca2+ current, nickel-sensitive Na+-Ca2+ exchanger current, and transient outward current, but did not change the Na+ current and ultra-rapid delayed rectifier potassium current in LA cardiomyocytes. EGCG decreased intracellular Ca2+ transient and sarcoplasmic reticulum Ca2+ content in LA cardiomyocytes. Furthermore, EGCG decreased isoproterenol (ISO, 1μM)-induced burst firing. KT5823 (1μM) or KN93 (1μM) decreased the incidences of ISO-induced LA burst firing, which became lower with EGCG treatment. H89 (10μM) and KN92 (1μM) did not suppress the incidence of ISO-induced LA burst firing. However, EGCG decreased the incidences of ISO-induced LA burst firing in the presence of H89 or KN92. CONCLUSION EGCG directly regulates LA electrophysiological characteristics and Ca2+ homeostasis, and suppresses ISO-induced atrial arrhythmogenesis through inhibiting Ca2+/calmodulin or cGMP-dependent protein kinases.
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16
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Brunetti ND, Pellegrino PL, D'Arienzo G, Sai R, Ziccardi L, Santoro F, Gaglione A, Di Biase M. Catecholaminergic polymorphic ventricular tachycardia associated with sinus node dysfunction and junctional rhythm: Case report and literature review. J Electrocardiol 2016; 49:940-943. [DOI: 10.1016/j.jelectrocard.2016.07.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Indexed: 10/21/2022]
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17
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Tsai FC, Lin YC, Chang SH, Chang GJ, Hsu YJ, Lin YM, Lee YS, Wang CL, Yeh YH. Differential left-to-right atria gene expression ratio in human sinus rhythm and atrial fibrillation: Implications for arrhythmogenesis and thrombogenesis. Int J Cardiol 2016; 222:104-112. [PMID: 27494721 DOI: 10.1016/j.ijcard.2016.07.103] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 12/26/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) causes atrial remodeling, and the left atrium (LA) is the favored substrate for maintaining AF. It remains unclear if AF remodels both atria differently and contributes to LA arrhythmogenesis and thrombogenesis. Therefore, we wished to characterize the transcript profiles in the LA and right atrium (RA) in sinus rhythm (SR) and AF respectively. METHODS Paired LA and RA appendages acquired from patients receiving cardiac surgery were used for ion-channel- and whole-exome-based transcriptome analysis. The ultrastructure was evaluated by immunohistochemistry. RESULTS Twenty-two and twenty ion-channels and transporters were differentially expressed between the LA and RA in AF and SR, respectively. Among these, 15 genes were differentially expressed in parallel between AF and SR. AF was associated with increased LA/RA expression ratio in 9 ion channel-related genes, including genes related to calcium handling. In microarray, AF was associated with a differential LA/RA gene expression ratio in 309 genes, and was involved in atherosclerosis-related signaling. AF was associated with the upregulation of thrombogenesis-related genes in the LA appendage, including P2Y12, CD 36 and ApoE. Immunohistochemistry showed higher expressions of collagen-1, oxidative stress and TGF-β1 in the RA compared to the LA. CONCLUSIONS AF was associated with differential LA-to-RA gene expression related to specific ion channels and pathways as well as upregulation of thrombogenesis-related genes in the LA appendage. Targeting the molecular mechanisms underlying the LA-to-RA difference and AF-related remodeling in the LA appendage may help provide new therapeutic options in treating AF and preventing thromboembolism in AF.
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Affiliation(s)
- Feng-Chun Tsai
- Division of Cardiac Surgery, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Yen-Chen Lin
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Shang-Hung Chang
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Gwo-Jyh Chang
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University College of Medicine, Chang-Gung University, Taiwan
| | - Yu-Juei Hsu
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Yuan-Min Lin
- School of Dentistry, National Yang-Ming University, Taipei, Taiwan
| | - Yun-Shien Lee
- Department of Biotechnology, Ming-Chuan University, Taoyuan, Taiwan
| | - Chun-Li Wang
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Yung-Hsin Yeh
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan.
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18
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Tsai FC, Chang GJ, Hsu YJ, Lin YM, Lee YS, Chen WJ, Kuo CT, Yeh YH. Proinflammatory gene expression in patients undergoing mitral valve surgery and maze ablation for atrial fibrillation. J Thorac Cardiovasc Surg 2015; 151:1673-1682.e5. [PMID: 26774166 DOI: 10.1016/j.jtcvs.2015.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 11/27/2015] [Accepted: 12/05/2015] [Indexed: 12/12/2022]
Abstract
OBJECTIVE It is difficult to achieve rhythm control in patients with long-standing persistent atrial fibrillation (AF). The radiofrequency maze procedure is an effective means in curing AF with a variable recurrence rate depending on patient characteristics and AF duration. In these patients, the characteristics of the atrial substrate have not been well investigated. Because the inflammatory process has been shown to be important in the pathogenesis of AF, we sought to characterize the proinflammatory gene expression in left atria obtained from patients with AF undergoing mitral valve surgery combined with the maze procedure to distinguish the changes associated with AF and its recurrence after the surgical ablation. METHODS Left atrial appendages from 35 patients receiving mitral valve surgery were used for study. Ten patients had sinus rhythm (SR) and 25 patients had persistent AF for more than 1 year and underwent the maze procedure. Among the AF patients, 13 patients remained in SR (AF-SR) and 12 patients had recurrent AF during the 1-year clinical follow-up (AF-AF). The nCounter Human Inflammation Array (NanoString Technologies, Seattle, Wash) was used for evaluating proinflammatory gene expression. Quantitative polymerase chain reaction, Western blot, and immunohistochemistry were applied for studying messenger RNA and protein expression. RESULTS Of 144 expressed proinflammatory genes, the inflammation array analysis revealed that 32 genes were differentially expressed between AF (including AF-SR and AF-AF) and SR. Thirteen genes were differentially expressed between AF-SR and AF-AF. The array and quantitative polymerase chain reaction produced parallel results in analyzing the expression of particular genes. Concordant with the gene expression difference between AF and SR patients, rapid pacing increased the expressions of SHC1, RHOA, PDGFA, and TRAF2 in HL-1 myocytes, implicating a causative effect of tachyarrhythmia on these genes. Compared with AF-SR, AF-AF expressed more intense oxidative stress, upregulations of collagen, transforming growth factor beta 1, and intranuclear nuclear factor of activated T-cells. Regression analysis showed that increased left atrial diameter was associated with the expression of RHOA and STAT1. CONCLUSIONS Differential expression profiles of proflammatory genes were presented between SR and AF and between maintained SR and recurrent AF after the maze procedure. The identified inflammatory molecules associated with AF and failed surgical ablation may provide clues for developing new potential therapeutic targets to improve AF rhythm control.
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Affiliation(s)
- Feng-Chun Tsai
- Division of Cardiac Surgery, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Gwo-Jyh Chang
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Yu-Juei Hsu
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Yuan-Min Lin
- School of Dentistry, National Yang-Ming University, Taipei, Taiwan
| | - Yun-Shien Lee
- Department of Biotechnology, Ming-Chuan University, Taoyuan, Taiwan
| | - Wei-Jan Chen
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Chi-Tai Kuo
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan
| | - Yung-Hsin Yeh
- Cardiovascular Division, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taoyuan, Taiwan.
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19
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Němec J, Kim JJ, Salama G. The link between abnormal calcium handling and electrical instability in acquired long QT syndrome--Does calcium precipitate arrhythmic storms? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:210-21. [PMID: 26631594 DOI: 10.1016/j.pbiomolbio.2015.11.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 11/17/2015] [Accepted: 11/19/2015] [Indexed: 12/19/2022]
Abstract
Release of Ca(2+) ions from sarcoplasmic reticulum (SR) into myocyte cytoplasm and their binding to troponin C is the final signal form myocardial contraction. Synchronous contraction of ventricular myocytes is necessary for efficient cardiac pumping function. This requires both shuttling of Ca(2+) between SR and cytoplasm in individual myocytes, and organ-level synchronization of this process by means of electrical coupling among ventricular myocytes. Abnormal Ca(2+) release from SR causes arrhythmias in the setting of CPVT (catecholaminergic polymorphic ventricular tachycardia) and digoxin toxicity. Recent optical mapping data indicate that abnormal Ca(2+) handling causes arrhythmias in models of both repolarization impairment and profound bradycardia. The mechanisms involve dynamic spatial heterogeneity of myocardial Ca(2+) handling preceding arrhythmia onset, cell-synchronous systolic secondary Ca(2+) elevation (SSCE), as well as more complex abnormalities of intracellular Ca(2+) handling detected by subcellular optical mapping in Langendorff-perfused hearts. The regional heterogeneities in Ca(2+) handling cause action potential (AP) heterogeneities through sodium-calcium exchange (NCX) activation and eventually overwhelm electrical coupling of the tissue. Divergent Ca(2+) dynamics among different myocardial regions leads to temporal instability of AP duration and - on the patient level - in T wave lability. Although T-wave alternans has been linked to cardiac arrhythmias, non-alternans lability is observed in pre-clinical models of the long QT syndrome (LQTS) and CPVT, and in LQTS patients. Analysis of T wave lability may provide a real-time window on the abnormal Ca(2+) dynamics causing specific arrhythmias such as Torsade de Pointes (TdP).
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Affiliation(s)
- Jan Němec
- Department of Medicine, Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jong J Kim
- Department of Medicine, Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Guy Salama
- Department of Medicine, Heart and Vascular Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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20
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Antoons G, Johnson DM, Dries E, Santiago DJ, Ozdemir S, Lenaerts I, Beekman JDM, Houtman MJC, Sipido KR, Vos MA. Calcium release near L-type calcium channels promotes beat-to-beat variability in ventricular myocytes from the chronic AV block dog. J Mol Cell Cardiol 2015; 89:326-34. [PMID: 26454162 DOI: 10.1016/j.yjmcc.2015.10.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 09/08/2015] [Accepted: 10/06/2015] [Indexed: 11/25/2022]
Abstract
Beat-to-beat variability of ventricular repolarization (BVR) has been proposed as a strong predictor of Torsades de Pointes (TdP). BVR is also observed at the myocyte level, and a number of studies have shown the importance of calcium handling in influencing this parameter. The chronic AV block (CAVB) dog is a model of TdP arrhythmia in cardiac hypertrophy, and myocytes from these animals show extensive remodeling, including of Ca(2+) handling. This remodeling process also leads to increased BVR. We aimed to determine the role that (local) Ca(2+) handling plays in BVR. In isolated LV myocytes an exponential relationship was observed between BVR magnitude and action potential duration (APD) at baseline. Inhibition of Ca(2+) release from sarcoplasmic reticulum (SR) with thapsigargin resulted in a reduction of [Ca(2+)]i, and of both BVR and APD. Increasing ICaL in the presence of thapsigargin restored APD but BVR remained low. In contrast, increasing ICaL with preserved Ca(2+) release increased both APD and BVR. Inhibition of Ca(2+) release with caffeine, as with thapsigargin, reduced BVR despite maintained APD. Simultaneous inhibition of Na(+)/Ca(2+) exchange and ICaL decreased APD and BVR to similar degrees, whilst increasing diastolic Ca(2+). Buffering of Ca(2+) transients with BAPTA reduced BVR for a given APD to a greater extent than buffering with EGTA, suggesting subsarcolemmal Ca(2+) transients modulated BVR to a larger extent than the cytosolic Ca(2+) transient. In conclusion, BVR in hypertrophied dog myocytes, at any APD, is strongly dependent on SR Ca(2+) release, which may act through modulation of the l-type Ca(2+) current in a subsarcolemmal microdomain.
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Affiliation(s)
- Gudrun Antoons
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands; Department of Physiology, Maastricht University, Maastricht, The Netherlands
| | - Daniel M Johnson
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium
| | - Eef Dries
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium
| | - Demetrio J Santiago
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium
| | - Semir Ozdemir
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium; Department of Biophysics, Akdeniz University, Antalya, Turkey
| | - Ilse Lenaerts
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium
| | - Jet D M Beekman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Marien J C Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
| | - Karin R Sipido
- Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven (University of Leuven), Leuven, Belgium.
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands
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Abstract
Despite improvements in the therapy of underlying heart disease, sudden cardiac death is a major cause of death worldwide. Disturbed Na and Ca handling is known to be a major predisposing factor for life-threatening tachyarrhythmias. In cardiomyocytes, many ion channels and transporters, including voltage-gated Na and Ca channels, cardiac ryanodine receptors, Na/Ca-exchanger, and SR Ca-ATPase are involved in this regulation. We have learned a lot about the pathophysiological relevance of disturbed ion channel function from monogenetic disorders. Changes in the gating of a single ion channel and the activity of an ion pump suffice to dramatically increase the propensity for arrhythmias even in structurally normal hearts. Nevertheless, patients with heart failure with acquired dysfunction in many ion channels and transporters exhibit profound dysregulation of Na and Ca handling and Ca/calmodulin-dependent protein kinase and are especially prone to arrhythmias. A deeper understanding of the underlying arrhythmic principles is mandatory if we are to improve their outcome. This review addresses basic tachyarrhythmic mechanisms, the underlying ionic mechanisms and the consequences for ion homeostasis, and the situation in complex diseases like heart failure.
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Affiliation(s)
- Stefan Wagner
- From the Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.W., L.S.M.); and Department of Pharmacology, University of California, Davis, CA (D.M.B.)
| | - Lars S Maier
- From the Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.W., L.S.M.); and Department of Pharmacology, University of California, Davis, CA (D.M.B.).
| | - Donald M Bers
- From the Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany (S.W., L.S.M.); and Department of Pharmacology, University of California, Davis, CA (D.M.B.)
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22
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Terentyev D, Rees CM, Li W, Cooper LL, Jindal HK, Peng X, Lu Y, Terentyeva R, Odening KE, Daley J, Bist K, Choi BR, Karma A, Koren G. Hyperphosphorylation of RyRs underlies triggered activity in transgenic rabbit model of LQT2 syndrome. Circ Res 2014; 115:919-28. [PMID: 25249569 DOI: 10.1161/circresaha.115.305146] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Loss-of-function mutations in human ether go-go (HERG) potassium channels underlie long QT syndrome type 2 (LQT2) and are associated with fatal ventricular tachyarrhythmia. Previously, most studies focused on plasma membrane-related pathways involved in arrhythmogenesis in long QT syndrome, whereas proarrhythmic changes in intracellular Ca(2+) handling remained unexplored. OBJECTIVE We investigated the remodeling of Ca(2+) homeostasis in ventricular cardiomyocytes derived from transgenic rabbit model of LQT2 to determine whether these changes contribute to triggered activity in the form of early after depolarizations (EADs). METHODS AND RESULTS Confocal Ca(2+) imaging revealed decrease in amplitude of Ca(2+) transients and sarcoplasmic reticulum Ca(2+) content in LQT2 myocytes. Experiments using sarcoplasmic reticulum-entrapped Ca(2+) indicator demonstrated enhanced ryanodine receptor (RyR)-mediated sarcoplasmic reticulum Ca(2+) leak in LQT2 cells. Western blot analyses showed increased phosphorylation of RyR in LQT2 myocytes versus controls. Coimmunoprecipitation experiments demonstrated loss of protein phosphatases type 1 and type 2 from the RyR complex. Stimulation of LQT2 cells with β-adrenergic agonist isoproterenol resulted in prolongation of the plateau of action potentials accompanied by aberrant Ca(2+) releases and EADs, which were abolished by inhibition of Ca(2+)/calmodulin-dependent protein kinase type 2. Computer simulations showed that late aberrant Ca(2+) releases caused by RyR hyperactivity promote EADs and underlie the enhanced triggered activity through increased forward mode of Na(+)/Ca(2+) exchanger type 1. CONCLUSIONS Hyperactive, hyperphosphorylated RyRs because of reduced local phosphatase activity enhance triggered activity in LQT2 syndrome. EADs are promoted by aberrant RyR-mediated Ca(2+) releases that are present despite a reduction of sarcoplasmic reticulum content. Those releases increase forward mode Na(+)/Ca(2+) exchanger type 1, thereby slowing repolarization and enabling L-type Ca(2+) current reactivation.
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Affiliation(s)
- Dmitry Terentyev
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.).
| | - Colin M Rees
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Weiyan Li
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Leroy L Cooper
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Hitesh K Jindal
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Xuwen Peng
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Yichun Lu
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Radmila Terentyeva
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Katja E Odening
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Jean Daley
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Kamana Bist
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Bum-Rak Choi
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Alain Karma
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.)
| | - Gideon Koren
- From the Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, Alpert Medical School of Brown University, Providence (D.T., W.L., L.L.C., H.K.J., Y.L., R.T., J.D., K.B., B.-R.C., G.K.); Physics Department, Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA (C.M.R., A.K.); Department of Comparative Medicine, Pennsylvania State University College of Medicine, Hershey (X.P.); and Department of Cardiology and Angiology I, Heart Center Freiburg University, Freiburg, Germany (K.E.O.).
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Heijman J, Voigt N, Wehrens XHT, Dobrev D. Calcium dysregulation in atrial fibrillation: the role of CaMKII. Front Pharmacol 2014; 5:30. [PMID: 24624086 PMCID: PMC3940963 DOI: 10.3389/fphar.2014.00030] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 02/15/2014] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most frequently encountered clinical arrhythmia and is associated with increased morbidity and mortality. Ectopic activity and reentry are considered major arrhythmogenic mechanisms contributing to the initiation and maintenance of AF. In addition, AF is self-reinforcing through progressive electrical and structural remodeling which stabilize the arrhythmia and make it more difficult to treat. Recent research has suggested an important role for Ca(2+)-dysregulation in AF. Ca(2+)-handling abnormalities may promote ectopic activity, conduction abnormalities facilitating reentry, and AF-related remodeling. In this review article, we summarize the Ca(2+)-handling derangements occurring in AF and discuss their impact on fundamental arrhythmogenic mechanisms. We focus in particular on the role of the multifunctional Ca(2+)/calmodulin-dependent protein kinase type-II (CaMKII), which acts as a major link between Ca(2+)-dysregulation and arrhythmogenesis. CaMKII expression and activity are increased in AF and promote arrhythmogenesis through phosphorylation of various targets involved in cardiac electrophysiology and excitation-contraction coupling. We discuss the implications for potential novel therapeutic strategies for AF based on CaMKII and Ca(2+)-handling abnormalities.
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Affiliation(s)
- Jordi Heijman
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen Essen, Germany
| | - Niels Voigt
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen Essen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Departments of Molecular Physiology and Biophysics, and Medicine-Cardiology, Baylor College of Medicine Houston, TX, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen Essen, Germany
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24
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Vandersickel N, Kazbanov IV, Nuitermans A, Weise LD, Pandit R, Panfilov AV. A study of early afterdepolarizations in a model for human ventricular tissue. PLoS One 2014; 9:e84595. [PMID: 24427289 PMCID: PMC3888406 DOI: 10.1371/journal.pone.0084595] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 11/15/2013] [Indexed: 12/13/2022] Open
Abstract
Sudden cardiac death is often caused by cardiac arrhythmias. Recently, special attention has been given to a certain arrhythmogenic condition, the long-QT syndrome, which occurs as a result of genetic mutations or drug toxicity. The underlying mechanisms of arrhythmias, caused by the long-QT syndrome, are not fully understood. However, arrhythmias are often connected to special excitations of cardiac cells, called early afterdepolarizations (EADs), which are depolarizations during the repolarizing phase of the action potential. So far, EADs have been studied mainly in isolated cardiac cells. However, the question on how EADs at the single-cell level can result in fibrillation at the tissue level, especially in human cell models, has not been widely studied yet. In this paper, we study wave patterns that result from single-cell EAD dynamics in a mathematical model for human ventricular cardiac tissue. We induce EADs by modeling experimental conditions which have been shown to evoke EADs at a single-cell level: by an increase of L-type Ca currents and a decrease of the delayed rectifier potassium currents. We show that, at the tissue level and depending on these parameters, three types of abnormal wave patterns emerge. We classify them into two types of spiral fibrillation and one type of oscillatory dynamics. Moreover, we find that the emergent wave patterns can be driven by calcium or sodium currents and we find phase waves in the oscillatory excitation regime. From our simulations we predict that arrhythmias caused by EADs can occur during normal wave propagation and do not require tissue heterogeneities. Experimental verification of our results is possible for experiments at the cell-culture level, where EADs can be induced by an increase of the L-type calcium conductance and by the application of I blockers, and the properties of the emergent patterns can be studied by optical mapping of the voltage and calcium.
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Affiliation(s)
- Nele Vandersickel
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
- * E-mail:
| | - Ivan V. Kazbanov
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
| | - Anita Nuitermans
- Department of Theoretical Biology, Utrecht University, Utrecht, The Netherlands
| | - Louis D. Weise
- Department of Physics and Astronomy, Ghent University, Ghent, Belgium
- Department of Theoretical Biology, Utrecht University, Utrecht, The Netherlands
| | - Rahul Pandit
- Center for Condensed Matter Theory - Department of Physics, Indian Institute of Science, Bangalore, India
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25
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Manning JR, Yin G, Kaminski CN, Magyar J, Feng H, Penn J, Sievert G, Thompson K, Jin J, Andres DA, Satin J. Rad GTPase deletion increases L-type calcium channel current leading to increased cardiac contraction. J Am Heart Assoc 2013; 2:e000459. [PMID: 24334906 PMCID: PMC3886777 DOI: 10.1161/jaha.113.000459] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND The small GTPase Rad is a negative regulator of voltage-dependent L-type calcium channel current (ICaL); however, the effects of Rad ablation on cardiomyocyte function are unknown. The objective of this study is to test the hypothesis that Rad-depletion causes positive inotropic effects without inducing cardiac hypertrophy. METHODS AND RESULTS Ventricular myocytes from adult Rad(-/-) mice were isolated and evaluated by patch-clamp recordings for I(Ca,L) and action potentials, Ca(2+) transients, and sarcomere shortening. Maximum I(CaL) is elevated in Rad(-/-) (maximal conductance 0.35 ± 0.04 picoSiemens/picoFarad (pS/pF) wild-type; 0.61 ± 0.14 pS/pF Rad(-/-)), decay kinetics are faster, and I(Ca,L) activates at lower voltages (activation midpoint -7.2 ± 0.6 wild-type; -11.7 ± 0.9 Rad(-/-)) mimicking effects of β-adrenergic receptor stimulation. Diastolic and twitch calcium are elevated in Rad(-/-) (F340/380: 1.03 diastolic and 0.35 twitch for wild-type; 1.47 diastolic and 0.736 twitch for Rad(-/-)) and sarcomere shortening is enhanced (4.31% wild-type; 14.13% Rad(-/-)) at lower pacing frequencies. Consequentially, frequency-dependence of Ca(2+) transients is less in Rad(-/-), and the frequency dependence of relaxation is also blunted. In isolated working hearts, similar results were obtained; chiefly, +dP/dt was elevated at baseline and developed pressure was relatively nonresponsive to acute β-adrenergic receptor stimulation. In single cells, at subphysiological frequencies, nonstimulated calmodulin-dependent protein kinase-sensitive calcium release is observed. Remarkably, Rad(-/-) hearts did not show hypertrophic growth despite elevated levels of diastolic calcium. CONCLUSIONS This study demonstrates that the depletion of Rad GTPase is equivalent to sympathomimetic β-adrenergic receptor, without stimulating cardiac hypertrophy. Thus, targeting Rad GTPase is a novel potential therapeutic target for Ca(2+)-homeostasis-driven positive inotropic support of the heart.
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Affiliation(s)
- Janet R. Manning
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY (J.R.M., G.Y., J.M., J.P., G.S., J.S.)
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY (J.R.M., C.N.K., D.A.A.)
| | - Guo Yin
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY (J.R.M., G.Y., J.M., J.P., G.S., J.S.)
| | - Catherine N. Kaminski
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY (J.R.M., C.N.K., D.A.A.)
| | - Janos Magyar
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY (J.R.M., G.Y., J.M., J.P., G.S., J.S.)
- Department of Physiology, University of Debrecen, Hungary (J.M.)
| | - Han‐Zhong Feng
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI (H.Z.F., J.)
| | - John Penn
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY (J.R.M., G.Y., J.M., J.P., G.S., J.S.)
| | - Gail Sievert
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY (J.R.M., G.Y., J.M., J.P., G.S., J.S.)
| | - Katherine Thompson
- Department of Statistics, University of Kentucky College of Medicine, Lexington, KY (K.T.)
| | - J.‐P. Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI (H.Z.F., J.)
| | - Douglas A. Andres
- Department of Molecular and Cellular Biochemistry, University of Kentucky College of Medicine, Lexington, KY (J.R.M., C.N.K., D.A.A.)
| | - Jonathan Satin
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY (J.R.M., G.Y., J.M., J.P., G.S., J.S.)
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26
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Li W, Wang YP, Gao L, Zhang PP, Zhou Q, Xu QF, Zhou ZW, Guo K, Chen RH, Yang HT, Li YG. Resveratrol protects rabbit ventricular myocytes against oxidative stress-induced arrhythmogenic activity and Ca2+ overload. Acta Pharmacol Sin 2013; 34:1164-73. [PMID: 23912472 DOI: 10.1038/aps.2013.82] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/15/2013] [Indexed: 12/31/2022] Open
Abstract
AIM To investigate whether resveratrol suppressed oxidative stress-induced arrhythmogenic activity and Ca(2+) overload in ventricular myocytes and to explore the underlying mechanisms. METHODS Hydrogen peroxide (H2O2, 200 μmol/L)) was used to induce oxidative stress in rabbit ventricular myocytes. Cell shortening and calcium transients were simultaneously recorded to detect arrhythmogenic activity and to measure intracellular Ca(2+) ([Ca(2+)]i). Ca(2+)/calmodulin-dependent protein kinases II (CaMKII) activity was measured using a CaMKII kit or Western blotting analysis. Voltage-activated Na(+) and Ca(2+) currents were examined using whole-cell recording in myocytes. RESULTS H2O2 markedly prolonged Ca(2+) transient duration (CaTD), and induced early afterdepolarization (EAD)-like and delayed afterdepolarization (DAD)-like arrhythmogenic activity in myocytes paced at 0.16 Hz or 0.5 Hz. Application of resveratrol (30 or 50 μmol/L) dose-dependently suppressed H2O2-induced EAD-like arrhythmogenic activity and attenuated CaTD prolongation. Co-treatment with resveratrol (50 μmol/L) effectively prevented both EAD-like and DAD-like arrhythmogenic activity induced by H2O2. In addition, resveratrol markedly blunted H2O2-induced diastolic [Ca(2+)]i accumulation and prevented the myocytes from developing hypercontracture. In whole-cell recording studies, H2O2 significantly enhanced the late Na(+) current (I(Na,L)) and L-type Ca(2+) current (I(Ca,L)) in myocytes, which were dramatically suppressed or prevented by resveratrol. Furthermore, H2O2-induced ROS production and CaMKII activation were significantly prevented by resveratrol. CONCLUSION Resveratrol protects ventricular myocytes against oxidative stress-induced arrhythmogenic activity and Ca(2+) overload through inhibition of I(Na,L)/I(Ca,L), reduction of ROS generation, and prevention of CaMKII activation.
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27
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Le Quang K, Benito B, Naud P, Qi XY, Shi YF, Tardif JC, Gillis MA, Dobrev D, Charpentier F, Nattel S. T-Type Calcium Current Contributes to Escape Automaticity and Governs the Occurrence of Lethal Arrhythmias After Atrioventricular Block in Mice. Circ Arrhythm Electrophysiol 2013; 6:799-808. [DOI: 10.1161/circep.113.000407] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Khai Le Quang
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
| | - Begoña Benito
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
| | - Patrice Naud
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
| | - Xiao Yan Qi
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
| | - Yan Fen Shi
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
| | - Jean-Claude Tardif
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
| | - Marc-Antoine Gillis
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
| | - Dobromir Dobrev
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
| | - Flavien Charpentier
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
| | - Stanley Nattel
- From the Department of Medicine and Research Centre, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada (K.L.Q., B.B., P.N., X.Y.Q., Y.F.S., J.-C.T., M.-A.G., S.N.); Department of Medicine, Laval University, Quebec, Canada (K.L.Q.); IMIM Parc de Salut Mar, Hospital del Mar, Barcelona, Spain (B.B.); Institute of Pharmacology, University of Duisburg-Essen, Essen, Germany (D.D.); Division of Experimental Cardiology, University of Heidelberg, Heidelberg, Germany (D.D.); and
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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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Saegusa N, Garg V, Spitzer KW. Modulation of ventricular transient outward K⁺ current by acidosis and its effects on excitation-contraction coupling. Am J Physiol Heart Circ Physiol 2013; 304:H1680-96. [PMID: 23585132 DOI: 10.1152/ajpheart.00070.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The contribution of transient outward current (Ito) to changes in ventricular action potential (AP) repolarization induced by acidosis is unresolved, as is the indirect effect of these changes on calcium handling. To address this issue we measured intracellular pH (pHi), Ito, L-type calcium current (ICa,L), and calcium transients (CaTs) in rabbit ventricular myocytes. Intracellular acidosis [pHi 6.75 with extracellular pH (pHo) 7.4] reduced Ito by ~50% in myocytes with both high (epicardial) and low (papillary muscle) Ito densities, with little effect on steady-state inactivation and activation. Of the two candidate α-subunits underlying Ito, human (h)Kv4.3 and hKv1.4, only hKv4.3 current was reduced by intracellular acidosis. Extracellular acidosis (pHo 6.5) shifted Ito inactivation toward less negative potentials but had negligible effect on peak current at +60 mV when initiated from -80 mV. The effects of low pHi-induced inhibition of Ito on AP repolarization were much greater in epicardial than papillary muscle myocytes and included slowing of phase 1, attenuation of the notch, and elevation of the plateau. Low pHi increased AP duration in both cell types, with the greatest lengthening occurring in epicardial myocytes. The changes in epicardial AP repolarization induced by intracellular acidosis reduced peak ICa,L, increased net calcium influx via ICa,L, and increased CaT amplitude. In summary, in contrast to low pHo, intracellular acidosis has a marked inhibitory effect on ventricular Ito, perhaps mediated by Kv4.3. By altering the trajectory of the AP repolarization, low pHi has a significant indirect effect on calcium handling, especially evident in epicardial cells.
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Affiliation(s)
- Noriko Saegusa
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112, USA
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30
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Electrical storm: recent pathophysiological insights and therapeutic consequences. Basic Res Cardiol 2013; 108:336. [DOI: 10.1007/s00395-013-0336-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 01/29/2013] [Accepted: 02/04/2013] [Indexed: 01/01/2023]
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31
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Rokita AG, Anderson ME. New therapeutic targets in cardiology: arrhythmias and Ca2+/calmodulin-dependent kinase II (CaMKII). Circulation 2013; 126:2125-39. [PMID: 23091085 DOI: 10.1161/circulationaha.112.124990] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Adam G Rokita
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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32
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van der Bijl P, Heradien M, Doubell A, Brink P. QTc prolongation prior to angiography predicts poor outcome and associates significantly with lower left ventricular ejection fractions and higher left ventricular end-diastolic pressures. Cardiovasc J Afr 2012. [PMID: 23192258 PMCID: PMC3721884 DOI: 10.5830/cvja-2012-060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Background QT prolongation on the surface ECG is associated with sudden cardiac death. The cause of QT prolongation in ischaemic heart disease (IHD) patients remains unknown, but may be due to a complex interplay between genetic factors and impaired systolic and/or diastolic function through as yet unexplained mechanisms. It was hypothesised that QT prolongation before elective coronary angiography is associated with an increased mortality at six months. Methods Complete records of 321 patients who underwent coronary angiography were examined for QT interval corrected for heart rate (QTc), left ventricular ejection fraction (LVEF), left ventricular end-diastolic pressure (LVEDP) and known ischaemic heart disease risk factors. Patients were designated long QTc (LQTc) when they had prolonged QTc intervals or normal QTc (NQTc) when the QTc interval was normal. Patients with atrial fibrillation, bundle branch blocks, no ECG in the 24 hours before angiography, or a creatinine level > 200 μmol/l were excluded. Survival was determined telephonically at six months. Results Twenty-eight per cent of the total population had LQTc. During follow up, 15 patients (4.7%) died suddenly, 73% of whom had a LQTc. LQTc was significantly associated with mortality (LQTc 12% vs NQTc 1.7%; p < 0.01), and with lower but normal LVEF (LQTc 52.9 ± 15.4% vs NQTc 61.6 ± 13.6%; p < 0.01), higher LVEDP at LVEF > 45% (LQTc 19.2 ± 9.0 mmHg vs NQTc 15.95 ± 7.5 mmHg; p < 0.05), hypercholesterolaemia and a negative family history of IHD. Conclusion In patients with sinus rhythm and normal QRS width, QTc prolongation before coronary angiography predicted increased mortality at six months. QTc also associated strongly with left ventricular systolic and diastolic dysfunction, hypercholesterolaemia and a negative family history of IHD.
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Affiliation(s)
- P van der Bijl
- Division of Cardiology, Department of Medicine, Stellenbosch University and Tygerberg Academic Hospital, Western Cape, South Africa
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Effects of calmodulin-dependent protein kinase II inhibitor, KN-93, on electrophysiological features of rabbit hypertrophic cardiac myocytes. ACTA ACUST UNITED AC 2012; 32:485-489. [PMID: 22886958 DOI: 10.1007/s11596-012-0084-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Indexed: 10/28/2022]
Abstract
Cardiac hypertrophy is an independent risk factor for sudden cardiac death in clinical settings and the incidence of sudden cardiac death and ventricular arrhythmias are closely related. The aim of this study was to determine the effects of the calmodulin-dependent protein kinase (CaMK) II inhibitor, KN-93, on L-type calcium current (I(Ca, L)) and early after-depolarizations (EADs) in hypertrophic cardiomyocytes. A rabbit model of myocardial hypertrophy was constructed through abdominal aortic coarctation (LVH group). The control group (sham group) received a sham operation, in which the abdominal aortic was dissected but not coarcted. Eight weeks later, the degree of left ventricular hypertrophy (LVH) was evaluated using echocardiography. Individual cardiomyocyte was isolated through collagenase digestion. Action potentials (APs) and I(Ca, L) were recorded using the perforated patch clamp technique. APs were recorded under current clamp conditions and I(Ca, L) was recorded under voltage clamp conditions. The incidence of EADs and I(ca, L) in the hypertrophic cardiomyocytes were observed under the conditions of low potassium (2 mmol/L), low magnesium (0.25 mmol/L) Tyrode's solution perfusion, and slow frequency (0.25-0.5 Hz) electrical stimulation. The incidence of EADs and I(ca, L) in the hypertrophic cardiomyocytes were also evaluated after treatment with different concentrations of KN-92 (KN-92 group) and KN-93 (KN-93 group). Eight weeks later, the model was successfully established. Under the conditions of low potassium, low magnesium Tyrode's solution perfusion, and slow frequency electrical stimulation, the incidence of EADs was 0/12, 11/12, 10/12, and 5/12 in sham group, LVH group, KN-92 group (0.5 μmol/L), and KN-93 group (0.5 μmol/L), respectively. When the drug concentration was increased to 1 μmol/L in KN-92 group and KN-93 group, the incidence of EADs was 10/12 and 2/12, respectively. At 0 mV, the current density was 6.7±1.0 and 6.3±0.7 PA·PF(-1) in LVH group and sham group, respectively (P>0.05, n=12). When the drug concentration was 0.5 μmol/L in KN-92 and KN-93 groups, the peak I(Ca, L) at 0 mV was decreased by (9.4±2.8)% and (10.5±3.0)% in the hypertrophic cardiomyocytes of the two groups, respectively (P>0.05, n=12). When the drug concentration was increased to 1 μmol/L, the peak I(Ca, L) values were lowered by (13.4±3.7)% and (40±4.9)%, respectively (P<0.01, n=12). KN-93, a specific inhibitor of CaMKII, can effectively inhibit the occurrence of EADs in hypertrophic cardiomyocytes partially by suppressing I(Ca, L), which may be the main action mechanism of KN-93 antagonizing the occurrence of ventricular arrhythmias in hypertrophic myocardium.
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Swaminathan PD, Purohit A, Hund TJ, Anderson ME. Calmodulin-dependent protein kinase II: linking heart failure and arrhythmias. Circ Res 2012; 110:1661-77. [PMID: 22679140 DOI: 10.1161/circresaha.111.243956] [Citation(s) in RCA: 215] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Understanding relationships between heart failure and arrhythmias, important causes of suffering and sudden death, remains an unmet goal for biomedical researchers and physicians. Evidence assembled over the past decade supports a view that activation of the multifunctional Ca(2+) and calmodulin-dependent protein kinase II (CaMKII) favors myocardial dysfunction and cell membrane electrical instability. CaMKII activation follows increases in intracellular Ca(2+) or oxidation, upstream signals with the capacity to transition CaMKII into a Ca(2+) and calmodulin-independent constitutively active enzyme. Constitutively active CaMKII appears poised to participate in disease pathways by catalyzing the phosphorylation of classes of protein targets important for excitation-contraction coupling and cell survival, including ion channels and Ca(2+) homeostatic proteins, and transcription factors that drive hypertrophic and inflammatory gene expression. This rich diversity of downstream targets helps to explain the potential for CaMKII to simultaneously affect mechanical and electrical properties of heart muscle cells. Proof-of-concept studies from a growing number of investigators show that CaMKII inhibition is beneficial for improving myocardial performance and for reducing arrhythmias. We review the molecular physiology of CaMKII and discuss CaMKII actions at key cellular targets and results of animal models of myocardial hypertrophy, dysfunction, and arrhythmias that suggest CaMKII inhibition may benefit myocardial function while reducing arrhythmias.
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Affiliation(s)
- Paari Dominic Swaminathan
- Division of Cardiovascular Medicine, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Bourgonje VJA, Schoenmakers M, Beekman JDM, van der Nagel R, Houtman MJC, Miedema LF, Antoons G, Sipido K, de Windt LJ, van Veen TAB, Vos MA. Relevance of calmodulin/CaMKII activation for arrhythmogenesis in the AV block dog. Heart Rhythm 2012; 9:1875-83. [PMID: 22846339 DOI: 10.1016/j.hrthm.2012.07.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Indexed: 11/25/2022]
Abstract
BACKGROUND The calcium-dependent signaling molecules calcineurin and calcium/calmodulin-dependent protein kinase II (CaMKII) both have been linked to decompensated hypertrophy and arrhythmias. CaMKII is also believed to be involved in acute modulation of ion channels. OBJECTIVE The purpose of this study was to determine the role of calcineurin and CaMKII in a dog model of compensated hypertrophy and a long QT phenotype. METHODS AV block was created in dogs to induce ventricular remodeling, including enhanced susceptibility to dofetilide-induced torsades de pointes arrhythmias. Dogs were treated with cyclosporin A for 3 weeks, which reduced calcineurin activity, as determined by mRNA expression levels of regulator of calcineurin 1 exon 4, but which was unable to prevent structural, contractile, or electrical remodeling and arrhythmias. Biopsies were taken before and at 2 or 9 weeks after AV block. Western blots were performed against phosphorylated and total CaMKII, phospholamban, Akt, and histone deacetylase 4 (HDAC4). RESULTS Chronic AV block showed an increase in Akt, CaMKII and phospholamban phosphorylation levels, but HDAC4 phosphorylation remained unaltered. Dofetilide induced torsades de pointes in vivo and early afterdepolarizations in cardiomyocytes, and increased [Ca(2+)](i) and CaMKII autophosphorylation. Both W-7 and KN-93 treatment counteracted this. CONCLUSION The calcineurin pathway seems not to be involved in long-term cardiac remodeling of the chronic AV block dog. Although CaMKII is chronically activated, this does not translate to HDAC4 phosphorylation. However, acute CaMKII overactivation is able to initiate arrhythmias based on triggered activity.
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Affiliation(s)
- Vincent J A Bourgonje
- Department of Medical Physiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht, The Netherlands.
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Nattel S, Dobrev D. The multidimensional role of calcium in atrial fibrillation pathophysiology: mechanistic insights and therapeutic opportunities. Eur Heart J 2012; 33:1870-7. [PMID: 22507975 DOI: 10.1093/eurheartj/ehs079] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and its prevalence is increasing with the ageing of the population. Presently available treatment options are far from optimal and new insights into underlying mechanisms are needed to improve therapy. A variety of recent lines of research are converging to reveal important and relatively underappreciated multidimensional roles of cellular Ca(2+) content, distribution, and handling in AF pathophysiology. The objective of the present paper is to review the participation of changes in cell Ca(2+) and related processes in the mechanisms that lead to AF initiation and maintenance, and to consider the relevance of new knowledge in this area to therapeutic innovation. We first review the involvement of Ca(2+)-related functions in the principal arrhythmia mechanisms underlying AF: focal ectopic activity due to afterdepolarizations and re-entrant mechanisms. The detailed molecular pathophysiology of focal ectopic and re-entrant activity is then discussed in relationship to the participation of cell Ca(2+) changes and related Ca(2+)-handling and Ca(2+)-sensitive signalling systems. We then go on to consider the participation of Ca(2+)-related functions in electrical and structural remodelling processes leading to the AF substrate. Finally, we consider the implications for development of new arrhythmia management approaches and future research and development.
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Affiliation(s)
- Stanley Nattel
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, 5000 Belanger St E, Montreal, Quebec, Canada H1T 1C8.
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Abstract
Electrical storm (ES), characterized by recurrent ventricular tachycardia/fibrillation, is a serious condition, adversely affecting prognosis in patients with implantable cardioverter/defibrillators. Electrical storm patients often die of progressive heart failure, but the underlying molecular basis is poorly understood. We have recently created an animal model of ES that features repetitive implantable cardioverter/defibrillator firing for recurrent ventricular fibrillation and found that ES events cause striking activation of Ca(2+)/calmodulin-dependent protein kinase II and prominent alteration of Ca(2+)-handling protein phosphorylation, possibly explaining mechanical dysfunction and arrhythmia promotion that characterize ES. Here, the pathophysiology and potential therapeutic strategies for ES, based on experimental and clinical studies by us and others, are described.
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Alternative strategies in arrhythmia therapy: evaluation of Na/Ca exchange as an anti-arrhythmic target. Pharmacol Ther 2011; 134:26-42. [PMID: 22197992 DOI: 10.1016/j.pharmthera.2011.12.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 11/22/2011] [Accepted: 11/22/2011] [Indexed: 01/08/2023]
Abstract
The search for alternative anti-arrhythmic strategies is fueled by an unmet medical need as well as by the opportunities arising from identification of novel targets and novel drugs. Na/Ca exchange is a potential target involved in several types of arrhythmias, such as those related to ischemia-reperfusion, heart failure and also some forms of genetic arrhythmias. Inhibition of Na/Ca exchange is theoretically not only anti-arrhythmic but also increases cellular Ca(2+) content. This could be an advantage in conditions of low inotropy, such as in heart failure, but may also worsen conditions such as the recovery from ischemia or relaxation abnormalities. With the available drugs such as KB-R7943 and SEA-0400 these theories have now been tested in a number of cellular and in vivo models. Experience is overall rather positive and seems less hampered by the potential drawbacks than expected. This may be because the currently available drugs are not highly selective, with additional benefit derived from concurrent effects. While this precludes a definite answer regarding the benefit of a pure NCX inhibitor, they indicate that Na/Ca exchange inhibition as part of a multi-target strategy is an avenue to be considered. Such studies will need further 'bench' work and testing in relevant preclinical models, including chronic disease.
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Madhvani RV, Xie Y, Pantazis A, Garfinkel A, Qu Z, Weiss JN, Olcese R. Shaping a new Ca²⁺ conductance to suppress early afterdepolarizations in cardiac myocytes. J Physiol 2011; 589:6081-92. [PMID: 22025660 DOI: 10.1113/jphysiol.2011.219600] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Sudden cardiac death (SCD) due to ventricular fibrillation (VF) is a major world-wide health problem. A common trigger of VF involves abnormal repolarization of the cardiac action potential causing early afterdepolarizations (EADs). Here we used a hybrid biological-computational approach to investigate the dependence of EADs on the biophysical properties of the L-type Ca(2+) current (I(Ca,L)) and to explore how modifications of these properties could be designed to suppress EADs. EADs were induced in isolated rabbit ventricular myocytes by exposure to 600 μmol l(-1) H(2)O(2) (oxidative stress) or lowering the external [K(+)] from 5.4 to 2.0-2.7 mmol l(-1) (hypokalaemia). The role of I(Ca,L) in EAD formation was directly assessed using the dynamic clamp technique: the paced myocyte's V(m) was input to a myocyte model with tunable biophysical parameters, which computed a virtual I(Ca,L), which was injected into the myocyte in real time. This virtual current replaced the endogenous I(Ca,L), which was suppressed with nifedipine. Injecting a current with the biophysical properties of the native I(Ca,L) restored EAD occurrence in myocytes challenged by H(2)O(2) or hypokalaemia. A mere 5 mV depolarizing shift in the voltage dependence of activation or a hyperpolarizing shift in the steady-state inactivation curve completely abolished EADs in myocytes while maintaining a normal Ca(i) transient. We propose that modifying the biophysical properties of I(Ca,L) has potential as a powerful therapeutic strategy for suppressing EADs and EAD-mediated arrhythmias.
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Affiliation(s)
- Roshni V Madhvani
- Division of Molecular Medicine, Department of Anesthesiology, David Geffen School of Medicine at University of California, Los Angeles, CA 90095-7115, USA
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Fernández-Velasco M, Ruiz-Hurtado G, Rueda A, Neco P, Mercado-Morales M, Delgado C, Napolitano C, Priori SG, Richard S, María Gómez A, Benitah JP. RyRCa2+ leak limits cardiac Ca2+ window current overcoming the tonic effect of calmodulinin mice. PLoS One 2011; 6:e20863. [PMID: 21673970 PMCID: PMC3108979 DOI: 10.1371/journal.pone.0020863] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 05/13/2011] [Indexed: 11/19/2022] Open
Abstract
Ca2+ mediates the functional coupling between L-type Ca2+ channel (LTCC) and sarcoplasmic reticulum (SR) Ca2+ release channel (ryanodine receptor, RyR), participating in key pathophysiological processes. This crosstalk manifests as the orthograde Ca2+-induced Ca2+-release (CICR) mechanism triggered by Ca2+ influx, but also as the retrograde Ca2+-dependent inactivation (CDI) of LTCC, which depends on both Ca2+ permeating through the LTCC itself and on SR Ca2+ release through the RyR. This latter effect has been suggested to rely on local rather than global Ca2+ signaling, which might parallel the nanodomain control of CDI carried out through calmodulin (CaM). Analyzing the CICR in catecholaminergic polymorphic ventricular tachycardia (CPVT) mice as a model of RyR-generated Ca2+ leak, we evidence here that increased occurrence of the discrete local SR Ca2+ releases through the RyRs (Ca2+ sparks) causea depolarizing shift in activation and a hyperpolarizing shift inisochronic inactivation of cardiac LTCC current resulting in the reduction of window current. Both increasing fast [Ca2+]i buffer capacity or depleting SR Ca2+ store blunted these changes, which could be reproduced in WT cells by RyRCa2+ leak induced with Ryanodol and CaM inhibition.Our results unveiled a new paradigm for CaM-dependent effect on LTCC gating and further the nanodomain Ca2+ control of LTCC, emphasizing the importance of spatio-temporal relationships between Ca2+ signals and CaM function.
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Affiliation(s)
- María Fernández-Velasco
- Inserm, U637, Université Montpellier-1, Université Montpellier-2, Montpellier, France
- Instituto de Investigaciones Biomédicas Alberto Sols CSIC-UAM, Madrid, Spain
| | - Gema Ruiz-Hurtado
- Inserm, U637, Université Montpellier-1, Université Montpellier-2, Montpellier, France
- Inserm, U769, IFR141, Faculté de Pharmacie, Université Paris-Sud 11, Chatenay-Malabry, France
| | - Angélica Rueda
- Inserm, U637, Université Montpellier-1, Université Montpellier-2, Montpellier, France
- Department of Biochemistry, CINVESTAV, Mexico City, Mexico
| | - Patricia Neco
- Inserm, U637, Université Montpellier-1, Université Montpellier-2, Montpellier, France
- Inserm, U769, IFR141, Faculté de Pharmacie, Université Paris-Sud 11, Chatenay-Malabry, France
| | | | - Carmen Delgado
- Departamento de Farmacología, Facultad de Medicina, Universidad Complutense, CyB, CSIC, Madrid, Spain
| | - Carlo Napolitano
- Molecular Cardiology, Fondazione Salvatore Maugeri, Pavia, Italy
- Cardiovascular Genetics, Leon Charney Division of Cardiology, Langone Medical Center, New York University School of Medicine, New York, United States of America
| | - Silvia G. Priori
- Molecular Cardiology, Fondazione Salvatore Maugeri, Pavia, Italy
- Cardiovascular Genetics, Leon Charney Division of Cardiology, Langone Medical Center, New York University School of Medicine, New York, United States of America
- Department of Cardiology, University of Pavia, Italy
| | - Sylvain Richard
- Inserm, U637, Université Montpellier-1, Université Montpellier-2, Montpellier, France
- Inserm, U1046, Université Montpellier-1, Université Montpellier-2, Montpellier, France
| | - Ana María Gómez
- Inserm, U637, Université Montpellier-1, Université Montpellier-2, Montpellier, France
- Inserm, U769, IFR141, Faculté de Pharmacie, Université Paris-Sud 11, Chatenay-Malabry, France
| | - Jean-Pierre Benitah
- Inserm, U637, Université Montpellier-1, Université Montpellier-2, Montpellier, France
- Inserm, U769, IFR141, Faculté de Pharmacie, Université Paris-Sud 11, Chatenay-Malabry, France
- * E-mail:
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Ca2+ disorder caused by rapid electrical field stimulation can be modulated by CaMKIIδ expression in primary rat atrial myocytes. Biochem Biophys Res Commun 2011; 409:287-92. [DOI: 10.1016/j.bbrc.2011.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Accepted: 05/02/2011] [Indexed: 11/19/2022]
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Tsuji Y, Hojo M, Voigt N, El-Armouche A, Inden Y, Murohara T, Dobrev D, Nattel S, Kodama I, Kamiya K. Ca
2+
-Related Signaling and Protein Phosphorylation Abnormalities Play Central Roles in a New Experimental Model of Electrical Storm. Circulation 2011; 123:2192-203. [DOI: 10.1161/circulationaha.110.016683] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yukiomi Tsuji
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
| | - Mayumi Hojo
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
| | - Niels Voigt
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
| | - Ali El-Armouche
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
| | - Yasuya Inden
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
| | - Toyoaki Murohara
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
| | - Dobromir Dobrev
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
| | - Stanley Nattel
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
| | - Itsuo Kodama
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
| | - Kaichiro Kamiya
- From the Department of Cardiovascular Research, Research Institute of Environmental Medicine, Nagoya University (Y.T., M.H., I.K., K.K.), and Department of Cardiology, Nagoya Graduate School of Medicine (Y.I., T.M.), Nagoya, Japan; Department of Pharmacology, University Medical Center Göttingen of the Georg-August Universität, Göttingen, Germany (A.E.-A.); Department of Pharmacology and Toxicology, Dresden University of Technology, Dresden, Germany (N.V., D.D.); Division of Experimental Cardiology,
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Takahara A, Wagatsuma H, Aritomi S, Konda T, Akie Y, Nakamura Y, Sugiyama A. Measurements of cardiac ion channel subunits in the chronic atrioventricular block dog. J Pharmacol Sci 2011; 116:132-5. [PMID: 21512305 DOI: 10.1254/jphs.11019sc] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
The chronic atrioventricular block (CAVB) dog has been widely used as an in vivo proarrhythmia model. mRNA levels of K(+) and Ca(2+) channels in the isolated ventricular tissues from normal and CAVB dogs were assayed using a real-time PCR. The mRNA levels of KvLQT1 and MiRP1 were significantly less in the CAVB heart compared with those in the intact heart, whereas no significant difference was detected in the mRNA levels of other K(+)- or Ca(2+)-channel subunits. Adaptation against chronic bradycardia-related pathophysiology may have decreased the mRNA levels of cardiac K(+) channels, which may partly explain the arrhythmogenic property of this model.
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Affiliation(s)
- Akira Takahara
- Department of Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Toho University, Funabashi, Chiba 274-8510, Japan.
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Farkas AS, Nattel S. Minimizing Repolarization-Related Proarrhythmic Risk in Drug Development and Clinical Practice. Drugs 2010; 70:573-603. [DOI: 10.2165/11535230-000000000-00000] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Nattel S, Frelin Y, Gaborit N, Louault C, Demolombe S. Ion-channel mRNA-expression profiling: Insights into cardiac remodeling and arrhythmic substrates. J Mol Cell Cardiol 2009; 48:96-105. [PMID: 19631654 DOI: 10.1016/j.yjmcc.2009.07.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 06/17/2009] [Accepted: 07/09/2009] [Indexed: 11/20/2022]
Abstract
Membrane ion channels and transporters are key determinants of cardiac electrical function. Their expression is affected by cardiac region, hemodynamic properties, heart-rate changes, neurohormones and cardiac disease. One of the important determinants of ion-channel function is the level of ion-channel subunit mRNA expression, which governs the production of ion-channel proteins that traffic to the cell-membrane to form functional ion-channels. Ion-channel mRNA-expression profiling can be performed with cDNA microarrays or high-throughput reverse transcription/polymerase chain reaction (PCR) methods. Expression profiling has been applied to evaluate the dependence of ion-channel expression on cardiac region, revealing the molecular basis of regionally-controlled electrical properties as well as the molecular determinants of specialized electrical functions like pacemaking activity. Ion-channel remodeling occurs with cardiac diseases like heart failure, congenital repolarization abnormalities, and atrial fibrillation, and expression profiling has provided insights into the mechanisms by which these conditions affect cardiac electrical stability. Expression profiling has also shown how hormonal changes, antiarrhythmic drugs, cardiac development and altered heart rate affect ion-channel expression patterns to modify cardiac electrical function and sometimes to produce cardiac rhythm disturbances. This article reviews the information obtained to date with the application of cardiac ion-channel expression profiling. With increasing availability and efficiency of high-throughput PCR methods for ion-channel subunit mRNA-expression characterization, it is likely that the application of ion-channel expression profiling will increase and that it will provide important new insights into the determinants of cardiac electrical function in both physiological and pathological situations.
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Affiliation(s)
- Stanley Nattel
- Department of Medicine and Research Center, Montreal Heart Institute, Université de Montréal, Canada.
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