1
|
Abstract
Flecainide, a cardiac class 1C blocker of the surface membrane sodium channel (NaV1.5), has also been reported to reduce cardiac ryanodine receptor (RyR2)-mediated sarcoplasmic reticulum (SR) Ca2+ release. It has been introduced as a clinical antiarrhythmic agent for catecholaminergic polymorphic ventricular tachycardia (CPVT), a condition most commonly associated with gain-of-function RyR2 mutations. Current debate concerns both cellular mechanisms of its antiarrhythmic action and molecular mechanisms of its RyR2 actions. At the cellular level, it targets NaV1.5, RyR2, Na+/Ca2+ exchange (NCX), and additional proteins involved in excitation-contraction (EC) coupling and potentially contribute to the CPVT phenotype. This Viewpoint primarily addresses the various direct molecular actions of flecainide on isolated RyR2 channels in artificial lipid bilayers. Such studies demonstrate different, multifarious, flecainide binding sites on RyR2, with voltage-dependent binding in the channel pore or voltage-independent binding at distant peripheral sites. In contrast to its single NaV1.5 pore binding site, flecainide may bind to at least four separate inhibitory sites on RyR2 and one activation site. None of these binding sites have been specifically located in the linear RyR2 sequence or high-resolution structure. Furthermore, it is not clear which of the inhibitory sites contribute to flecainide's reduction of spontaneous Ca2+ release in cellular studies. A confounding observation is that flecainide binding to voltage-dependent inhibition sites reduces cation fluxes in a direction opposite to physiological Ca2+ flow from SR lumen to cytosol. This may suggest that, rather than directly blocking Ca2+ efflux, flecainide can reduce Ca2+ efflux by blocking counter currents through the pore which otherwise limit SR membrane potential change during systolic Ca2+ efflux. In summary, the antiarrhythmic effects of flecainide in CPVT seem to involve multiple components of EC coupling and multiple actions on RyR2. Their clarification may identify novel specific drug targets and facilitate flecainide's clinical utilization in CPVT.
Collapse
Affiliation(s)
| | - Christopher L.-H. Huang
- Department of Biochemistry, University of Cambridge, Cambridge, UK
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - James A. Fraser
- Physiological Laboratory, University of Cambridge, Cambridge, UK
| | - Angela F. Dulhunty
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Acton, Australia
| |
Collapse
|
2
|
Stutzman MJ, Kim CSJ, Tester DJ, Hamrick SK, Dotzler SM, Giudicessi JR, Miotto MC, Gc JB, Frank J, Marks AR, Ackerman MJ. Characterization of N-terminal RYR2 variants outside CPVT1 hotspot regions using patient iPSCs reveal pathogenesis and therapeutic potential. Stem Cell Reports 2022; 17:2023-2036. [PMID: 35931078 PMCID: PMC9481874 DOI: 10.1016/j.stemcr.2022.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 11/18/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a cardiac channelopathy causing ventricular tachycardia following adrenergic stimulation. Pathogenic variants in RYR2-encoded ryanodine receptor 2 (RYR2) cause CPVT1 and cluster into domains I–IV, with the most N-terminal domain involving residues 77–466. Patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were generated for RYR2-F13L, -L14P, -R15P, and -R176Q variants. Isogenic control iPSCs were generated using CRISPR-Cas9/PiggyBac. Fluo-4 Ca2+ imaging assessed Ca2+ handling with/without isoproterenol (ISO), nadolol (Nad), and flecainide (Flec) treatment. CPVT1 iPSC-CMs displayed increased Ca2+ sparking and Ca2+ transient amplitude following ISO compared with control. Combined Nad treatment/ISO stimulation reduced Ca2+ amplitude and sparking in variant iPSC-CMs. Molecular dynamic simulations visualized the structural role of these variants. We provide the first functional evidence that these most proximal N-terminal localizing variants alter calcium handling similar to CPVT1. These variants are located at the N-terminal domain and the central domain interface and could destabilize the RYR2 channel promoting Ca2+ leak-triggered arrhythmias. Extreme N-terminal RyR2 variants alter calcium handling similar to classical CPVT1 Abnormal Ca2+ kinetics as well as uncontrolled Ca2+ release underlies CPVT1 In vitro arrhythmia studies with iPSCs show nadolol is an effective treatment In silico 3D modeling of RYR2 revealed pathogenicity of N-terminal variants
Collapse
Affiliation(s)
- Marissa J Stutzman
- Department of Molecular Pharmacology and Experimental Therapeutics; Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN 55905, USA
| | - C S John Kim
- Department of Molecular Pharmacology and Experimental Therapeutics; Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN 55905, USA
| | - David J Tester
- Department of Molecular Pharmacology and Experimental Therapeutics; Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN 55905, USA; Department of Cardiovascular Medicine/Division of Heart Rhythm Services; Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, MN 55905, USA
| | - Samantha K Hamrick
- Department of Molecular Pharmacology and Experimental Therapeutics; Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN 55905, USA
| | - Steven M Dotzler
- Department of Molecular Pharmacology and Experimental Therapeutics; Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN 55905, USA
| | - John R Giudicessi
- Department of Molecular Pharmacology and Experimental Therapeutics; Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN 55905, USA; Department of Cardiovascular Medicine/Division of Heart Rhythm Services; Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, MN 55905, USA
| | - Marco C Miotto
- Department of Physiology and Cellular Biophysics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Jeevan B Gc
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York 10032, USA
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York 10032, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Michael J Ackerman
- Department of Molecular Pharmacology and Experimental Therapeutics; Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN 55905, USA; Department of Cardiovascular Medicine/Division of Heart Rhythm Services; Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, MN 55905, USA; Department of Pediatric and Adolescent Medicine/Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN 55905, USA.
| |
Collapse
|
3
|
Dulhunty AF. Molecular Changes in the Cardiac RyR2 With Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT). Front Physiol 2022; 13:830367. [PMID: 35222090 PMCID: PMC8867003 DOI: 10.3389/fphys.2022.830367] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/07/2022] [Indexed: 11/13/2022] Open
Abstract
The cardiac ryanodine receptor Ca2+ release channel (RyR2) is inserted into the membrane of intracellular sarcoplasmic reticulum (SR) myocyte Ca2+ stores, where it releases the Ca2+ essential for contraction. Mutations in proteins involved in Ca2+ signaling can lead to catecholaminergic polymorphic ventricular tachycardia (CPVT). The most common cellular phenotype in CPVT is higher than normal cytoplasmic Ca2+ concentrations during diastole due to Ca2+ leak from the SR through mutant RyR2. Arrhythmias are triggered when the surface membrane sodium calcium exchanger (NCX) lowers cytoplasmic Ca2+ by importing 3 Na+ ions to extrude one Ca2+ ion. The Na+ influx leads to delayed after depolarizations (DADs) which trigger arrhythmia when reaching action potential threshold. Present therapies use drugs developed for different purposes that serendipitously reduce RyR2 Ca2+ leak, but can adversely effect systolic Ca2+ release and other target processes. Ideal drugs would specifically reverse the effect of individual mutations, without altering normal channel function. Such drugs will depend on the location of the mutation in the 4967-residue monomer and the effect of the mutation on local structure, and downstream effects on structures along the conformational pathway to the pore. Such atomic resolution information is only now becoming available. This perspective provides a summary of known or predicted structural changes associated with a handful of CPVT mutations. Known molecular changes associated with RyR opening are discussed, as well one study where minute molecular changes with a particular mutation have been tracked from the N-terminal mutation site to gating residues in the channel pore.
Collapse
|
4
|
Woll KA, Van Petegem F. Calcium Release Channels: Structure and Function of IP3 Receptors and Ryanodine Receptors. Physiol Rev 2021; 102:209-268. [PMID: 34280054 DOI: 10.1152/physrev.00033.2020] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ca2+-release channels are giant membrane proteins that control the release of Ca2+ from the endoplasmic and sarcoplasmic reticulum. The two members, ryanodine receptors (RyRs) and inositol-1,4,5-trisphosphate Receptors (IP3Rs), are evolutionarily related and are both activated by cytosolic Ca2+. They share a common architecture, but RyRs have evolved additional modules in the cytosolic region. Their massive size allows for the regulation by tens of proteins and small molecules, which can affect the opening and closing of the channels. In addition to Ca2+, other major triggers include IP3 for the IP3Rs, and depolarization of the plasma membrane for a particular RyR subtype. Their size has made them popular targets for study via electron microscopic methods, with current structures culminating near 3Å. The available structures have provided many new mechanistic insights int the binding of auxiliary proteins and small molecules, how these can regulate channel opening, and the mechanisms of disease-associated mutations. They also help scrutinize previously proposed binding sites, as some of these are now incompatible with the structures. Many questions remain around the structural effects of post-translational modifications, additional binding partners, and the higher-order complexes these channels can make in situ. This review summarizes our current knowledge about the structures of Ca2+-release channels and how this informs on their function.
Collapse
Affiliation(s)
- Kellie A Woll
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
5
|
Pathological conformations of disease mutant Ryanodine Receptors revealed by cryo-EM. Nat Commun 2021; 12:807. [PMID: 33547325 PMCID: PMC7864917 DOI: 10.1038/s41467-021-21141-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 01/14/2021] [Indexed: 12/17/2022] Open
Abstract
Ryanodine Receptors (RyRs) are massive channels that release Ca2+ from the endoplasmic and sarcoplasmic reticulum. Hundreds of mutations are linked to malignant hyperthermia (MH), myopathies, and arrhythmias. Here, we explore the first MH mutation identified in humans by providing cryo-EM snapshots of the pig homolog, R615C, showing that it affects an interface between three solenoid regions. We also show the impact of apo-calmodulin (apoCaM) and how it can induce opening by bending of the bridging solenoid, mediated by its N-terminal lobe. For R615C RyR1, apoCaM binding abolishes a pathological ‘intermediate’ conformation, distributing the population to a mixture of open and closed channels, both different from the structure without apoCaM. Comparisons show that the mutation primarily affects the closed state, inducing partial movements linked to channel activation. This shows that disease mutations can cause distinct pathological conformations of the RyR and facilitate channel opening by disrupting interactions between different solenoid regions. Ryanodine Receptors (RyRs) release Ca2+ from the endoplasmic and sarcoplasmic reticulum. Mutations in RyR are linked to malignant hyperthermia (MH), myopathies, and arrhythmias. Here, a collection of cryoEM structures provides insights into the molecular consequences of MHrelated RyR mutation R615C, and how apoCaM opens RyR1.
Collapse
|
6
|
Kohno M, Kobayashi S, Yamamoto T, Yoshitomi R, Kajii T, Fujii S, Nakamura Y, Kato T, Uchinoumi H, Oda T, Okuda S, Watanabe K, Mizukami Y, Yano M. Enhancing calmodulin binding to cardiac ryanodine receptor completely inhibits pressure-overload induced hypertrophic signaling. Commun Biol 2020; 3:714. [PMID: 33244105 PMCID: PMC7691336 DOI: 10.1038/s42003-020-01443-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022] Open
Abstract
Cardiac hypertrophy is a well-known major risk factor for poor prognosis in patients with cardiovascular diseases. Dysregulation of intracellular Ca2+ is involved in the pathogenesis of cardiac hypertrophy. However, the precise mechanism underlying cardiac hypertrophy remains elusive. Here, we investigate whether pressure-overload induced hypertrophy can be induced by destabilization of cardiac ryanodine receptor (RyR2) through calmodulin (CaM) dissociation and subsequent Ca2+ leakage, and whether it can be genetically rescued by enhancing the binding affinity of CaM to RyR2. In the very initial phase of pressure-overload induced cardiac hypertrophy, when cardiac contractile function is preserved, reactive oxygen species (ROS)-mediated RyR2 destabilization already occurs in association with relaxation dysfunction. Further, stabilizing RyR2 by enhancing the binding affinity of CaM to RyR2 completely inhibits hypertrophic signaling and improves survival. Our study uncovers a critical missing link between RyR2 destabilization and cardiac hypertrophy.
Collapse
Affiliation(s)
- Michiaki Kohno
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Shigeki Kobayashi
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Takeshi Yamamoto
- Faculty of Health Sciences, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, 755-8505, Japan
| | - Ryosuke Yoshitomi
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Toshiro Kajii
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Shohei Fujii
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Yoshihide Nakamura
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Takayoshi Kato
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Hitoshi Uchinoumi
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Tetsuro Oda
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Shinichi Okuda
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan
| | - Kenji Watanabe
- Institute of Gene Research, Yamaguchi University Science Research Center, Yamaguchi, 755-8505, Japan
| | - Yoichi Mizukami
- Institute of Gene Research, Yamaguchi University Science Research Center, Yamaguchi, 755-8505, Japan
| | - Masafumi Yano
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi, 755-8505, Japan.
| |
Collapse
|
7
|
Connell P, Word TA, Wehrens XHT. Targeting pathological leak of ryanodine receptors: preclinical progress and the potential impact on treatments for cardiac arrhythmias and heart failure. Expert Opin Ther Targets 2020; 24:25-36. [PMID: 31869254 DOI: 10.1080/14728222.2020.1708326] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Introduction: Type-2 ryanodine receptor (RyR2) located on the sarcoplasmic reticulum initiate systolic Ca2+ transients within cardiomyocytes. Proper functioning of RyR2 is therefore crucial to the timing and force generated by cardiomyocytes within a healthy heart. Improper intracellular Ca2+ handing secondary to RyR2 dysfunction is associated with a variety of cardiac pathologies including catecholaminergic polymorphic ventricular tachycardia (CPVT), atrial fibrillation (AF), and heart failure (HF). Thus, RyR2 and its associated accessory proteins provide promising drug targets to scientists developing therapeutics for a variety of cardiac pathologies.Areas covered: In this article, we review the role of RyR2 in a variety of cardiac pathologies. We performed a literature search utilizing PubMed and MEDLINE as well as reviewed registries of trials from clinicaltrials.gov from 2010 to 2019 for novel therapeutic approaches that address the cellular mechanisms underlying CPVT, AF, and HF by specifically targeting defective RyR2 channels.Expert opinion: The negative impact of cardiac dysfunction on human health and medical economics are major motivating factors for establishing new and effective therapeutic approaches. Focusing on directly impacting the molecular mechanisms underlying defective Ca2+ handling by RyR2 in HF and arrhythmia has great potential to be translated into novel and innovative therapies.
Collapse
Affiliation(s)
- Patrick Connell
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.,Departments of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Tarah A Word
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.,Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA.,Departments of Pediatrics, Baylor College of Medicine, Houston, TX, USA.,Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA.,Medicine (Cardiology, Baylor College of Medicine, Houston, TX, USA.,Neuroscience, Baylor College of Medicine, Houston, TX, USA.,Center for Space Medicine, Baylor College of Medicine, Houston, TX, USA
| |
Collapse
|
8
|
Valdivia HH, Valdivia CR. Tetracaine derivatives for catecholaminergic polymorphic ventricular tachycardia: New drugs for correction of diastolic Ca 2+ leak? Heart Rhythm 2018; 15:587-588. [PMID: 29410362 DOI: 10.1016/j.hrthm.2018.01.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Indexed: 10/18/2022]
Affiliation(s)
- Héctor H Valdivia
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
| | - Carmen R Valdivia
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
| |
Collapse
|
9
|
Nishimura S, Yamamoto T, Nakamura Y, Kohno M, Hamada Y, Sufu Y, Fukui G, Nanno T, Ishiguchi H, Kato T, Xu X, Ono M, Oda T, Okuda S, Kobayashi S, Yano M. Mutation-linked, excessively tight interaction between the calmodulin binding domain and the C-terminal domain of the cardiac ryanodine receptor as a novel cause of catecholaminergic polymorphic ventricular tachycardia. Heart Rhythm 2018; 15:905-914. [PMID: 29427818 DOI: 10.1016/j.hrthm.2018.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUND Ryanodine receptor (RyR2) is known to be a causal gene of catecholaminergic polymorphic ventricular tachycardia (CPVT), an important inherited disease. Some of the human CPVT-associated mutations have been found in a domain (4026-4172) that has EF hand motifs, the so-called calmodulin (CaM)-like domain (CaMLD). OBJECTIVE The purpose of this study was to investigate the underlying mechanism by which CPVT is induced by a mutation at CaMLD. METHODS A new N4103K/+ knock-in (KI) mice model was generated. RESULTS Sustained ventricular tachycardia was frequently observed after infusion of caffeine plus epinephrine in KI mice. Endogenous CaM bound to RyR2 decreased even at baseline in isolated KI cardiomyocytes. Ca2+ spark frequency (CaSpF) was much higher in KI cells than in wild-type cells. Addition of GSH-CaM (higher affinity CaM to RyR2) significantly decreased CaSpF. In response to isoproterenol, spontaneous Ca2+ transient (SCaT) was frequently observed in intact KI cells. Incorporation of GSH-CaM into intact KI cells using a protein delivery kit decreased SCaT significantly. An assay using a quartz crystal microbalance technique revealed that mutated CaMLD peptide showed higher binding affinity to CaM binding domain (CaMBD) peptide. CONCLUSION In the N4103K mutant, CaM binding affinity to RyR2 was significantly reduced regardless of beta-adrenergic stimulation. We found that this was caused by an abnormally tight interaction between CaMBD and mutated CaM-like domain (N4103K-CaMBD). Thus, CaMBD-CaMLD interaction may be a novel therapeutic target for treatment of lethal arrhythmia.
Collapse
Affiliation(s)
- Shigehiko Nishimura
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Takeshi Yamamoto
- Faculty of Health Sciences, Yamaguchi University Graduate School of Medicine, Ube, Japan.
| | - Yoshihide Nakamura
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Michiaki Kohno
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Yoriomi Hamada
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Yoko Sufu
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Go Fukui
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Takuma Nanno
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Hironori Ishiguchi
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Takayoshi Kato
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Xiaojuan Xu
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Makoto Ono
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Tetsuro Oda
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Shinichi Okuda
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Shigeki Kobayashi
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Masafumi Yano
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| |
Collapse
|
10
|
Santulli G, Lewis D, des Georges A, Marks AR, Frank J. Ryanodine Receptor Structure and Function in Health and Disease. Subcell Biochem 2018; 87:329-352. [PMID: 29464565 PMCID: PMC5936639 DOI: 10.1007/978-981-10-7757-9_11] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Ryanodine receptors (RyRs) are ubiquitous intracellular calcium (Ca2+) release channels required for the function of many organs including heart and skeletal muscle, synaptic transmission in the brain, pancreatic beta cell function, and vascular tone. In disease, defective function of RyRs due either to stress (hyperadrenergic and/or oxidative overload) or genetic mutations can render the channels leaky to Ca2+ and promote defective disease-causing signals as observed in heat failure, muscular dystrophy, diabetes mellitus, and neurodegerative disease. RyRs are massive structures comprising the largest known ion channel-bearing macromolecular complex and exceeding 3 million Daltons in molecular weight. RyRs mediate the rapid release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR) to stimulate cellular functions through Ca2+-dependent processes. Recent advances in single-particle cryogenic electron microscopy (cryo-EM) have enabled the determination of atomic-level structures for RyR for the first time. These structures have illuminated the mechanisms by which these critical ion channels function and interact with regulatory ligands. In the present chapter we discuss the structure, functional elements, gating and activation mechanisms of RyRs in normal and disease states.
Collapse
Affiliation(s)
- Gaetano Santulli
- The Wu Center for Molecular Cardiology, Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, USA
- The Wilf Family Cardiovascular Research Institute and the Einstein-Mount Sinai Diabetes Research Center, Department of Medicine, Albert Einstein College of Medicine - Montefiore University Hospital, New York, NY, USA
| | - Daniel Lewis
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Amedee des Georges
- Advanced Science Research Center at the Graduate Center of the City University of New York, New York, NY, USA
- Department of Chemistry & Biochemistry, City College of New York, New York, NY, USA
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
- Department of Medicine, Columbia University, New York, NY, USA
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
- Department of Biological Sciences, Columbia University, New York, NY, USA.
| |
Collapse
|
11
|
Walweel K, Oo YW, Laver DR. The emerging role of calmodulin regulation of RyR2 in controlling heart rhythm, the progression of heart failure and the antiarrhythmic action of dantrolene. Clin Exp Pharmacol Physiol 2017; 44:135-142. [PMID: 27626620 DOI: 10.1111/1440-1681.12669] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 08/27/2016] [Accepted: 09/09/2016] [Indexed: 11/28/2022]
Abstract
Cardiac output and rhythm depend on the release and the take-up of calcium from the sarcoplasmic reticulum (SR). Excessive diastolic calcium leak from the SR due to dysfunctional calcium release channels (RyR2) contributes to the formation of delayed after-depolarizations, which underlie the fatal arrhythmias that occur in heart failure and inherited syndromes. Calmodulin (CaM) is a calcium-binding protein that regulates target proteins and acts as a calcium sensor. CaM is comprised of two calcium-binding EF-hand domains and a flexible linker. CaM is an accessory protein that partially inhibits RyR2 channel activity. CaM is critical for normal cardiac function, and altered CaM binding and efficacy may contribute to defects in SR calcium release. The present paper reviews CaM binding to RyR2 and how it regulates RyR2 channel activity. It then goes on to review how mutations in the CaM amino acid sequence give rise to inherited syndromes such as Catecholaminergic Polymorphic Ventricular Tachychardia (CPVT) and long QT syndrome (LQTS). In addition, the role of reduced CaM binding to RyR2 that results from RyR2 phosphorylation or from oxidation of either RyR2 or CaM contributes to the progression of heart failure is reviewed. Finally, this manuscript reviews recent evidence that CaM binding to RyR2 is required for the inhibitory action of a pharmaceutical agent (dantrolene) on RyR2. Dantrolene is a clinically used muscle relaxant that has recently been found to exert antiarrhythmic effects against SR Ca2+ overload arrhythmias.
Collapse
Affiliation(s)
- Kafa Walweel
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
| | - Ye Win Oo
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
| | - Derek R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, NSW, 2308, Australia
| |
Collapse
|
12
|
Faltinova A, Tomaskova N, Antalik M, Sevcik J, Zahradnikova A. The N-Terminal Region of the Ryanodine Receptor Affects Channel Activation. Front Physiol 2017; 8:443. [PMID: 28713282 PMCID: PMC5492033 DOI: 10.3389/fphys.2017.00443] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 06/12/2017] [Indexed: 11/29/2022] Open
Abstract
Mutations in the cardiac ryanodine receptor (RyR2), the ion channel responsible for release of calcium ions from intracellular stores into cytoplasm, are the cause of several inherited cardiac arrhythmias. At the molecular level, disease symptoms can be mimicked by domain peptides from mutation-prone regions of RyR2 that bind to RyR2 and activate it. Here we show that the domain peptide DPcpvtN2, corresponding to the central helix of the N-terminal region of RyR2, activates the RyR2 channel. Structural modeling of interaction between DPcpvtN2 and the N-terminal region of RyR2 in the closed and open conformation provided three plausible structures of the complex. Only one of them could explain the dependence of RyR2 activity on concentration of DPcpvtN2. The structure of the complex was at odds with the previously proposed “domain switch” mechanism of competition between domain peptides and ryanodine receptor domains. Likewise, in structural models of the N-terminal region, the conformational changes induced by DPcpvtN2 binding were different from those induced by mutation of central helix amino acids. The activating effect of DPcpvtN2 binding and of mutations in the central helix could be explained by their similar effect on the transition energy between the closed and open conformation of RyR2.
Collapse
Affiliation(s)
- Andrea Faltinova
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics of the Centre of Biosciences, Slovak Academy of SciencesBratislava, Slovakia.,Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of SciencesBratislava, Slovakia
| | - Nataša Tomaskova
- Faculty of Science, Institute of Chemical Sciences, Pavol Jozef Šafárik UniversityKošice, Slovakia
| | - Marián Antalik
- Faculty of Science, Institute of Chemical Sciences, Pavol Jozef Šafárik UniversityKošice, Slovakia
| | - Jozef Sevcik
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of SciencesBratislava, Slovakia
| | - Alexandra Zahradnikova
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics of the Centre of Biosciences, Slovak Academy of SciencesBratislava, Slovakia.,Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of SciencesBratislava, Slovakia
| |
Collapse
|
13
|
Santulli G, Lewis DR, Marks AR. Physiology and pathophysiology of excitation-contraction coupling: the functional role of ryanodine receptor. J Muscle Res Cell Motil 2017; 38:37-45. [PMID: 28653141 PMCID: PMC5813681 DOI: 10.1007/s10974-017-9470-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/06/2017] [Indexed: 12/21/2022]
Abstract
Calcium (Ca2+) release from intracellular stores plays a key role in the regulation of skeletal muscle contraction. The type 1 ryanodine receptors (RyR1) is the major Ca2+ release channel on the sarcoplasmic reticulum (SR) of myocytes in skeletal muscle and is required for excitation-contraction (E-C) coupling. This article explores the role of RyR1 in skeletal muscle physiology and pathophysiology.
Collapse
Affiliation(s)
- Gaetano Santulli
- The Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Daniel R Lewis
- The Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Andrew R Marks
- The Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA.
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, New York, NY, USA.
- Department of Medicine, Columbia University, New York, NY, USA.
| |
Collapse
|
14
|
Sasaki K, Makiyama T, Yoshida Y, Wuriyanghai Y, Kamakura T, Nishiuchi S, Hayano M, Harita T, Yamamoto Y, Kohjitani H, Hirose S, Chen J, Kawamura M, Ohno S, Itoh H, Takeuchi A, Matsuoka S, Miura M, Sumitomo N, Horie M, Yamanaka S, Kimura T. Patient-Specific Human Induced Pluripotent Stem Cell Model Assessed with Electrical Pacing Validates S107 as a Potential Therapeutic Agent for Catecholaminergic Polymorphic Ventricular Tachycardia. PLoS One 2016; 11:e0164795. [PMID: 27764147 PMCID: PMC5072719 DOI: 10.1371/journal.pone.0164795] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 09/30/2016] [Indexed: 12/21/2022] Open
Abstract
Introduction Human induced pluripotent stem cells (hiPSCs) offer a unique opportunity for disease modeling. However, it is not invariably successful to recapitulate the disease phenotype because of the immaturity of hiPSC-derived cardiomyocytes (hiPSC-CMs). The purpose of this study was to establish and analyze iPSC-based model of catecholaminergic polymorphic ventricular tachycardia (CPVT), which is characterized by adrenergically mediated lethal arrhythmias, more precisely using electrical pacing that could promote the development of new pharmacotherapies. Method and Results We generated hiPSCs from a 37-year-old CPVT patient and differentiated them into cardiomyocytes. Under spontaneous beating conditions, no significant difference was found in the timing irregularity of spontaneous Ca2+ transients between control- and CPVT-hiPSC-CMs. Using Ca2+ imaging at 1 Hz electrical field stimulation, isoproterenol induced an abnormal diastolic Ca2+ increase more frequently in CPVT- than in control-hiPSC-CMs (control 12% vs. CPVT 43%, p<0.05). Action potential recordings of spontaneous beating hiPSC-CMs revealed no significant difference in the frequency of delayed afterdepolarizations (DADs) between control and CPVT cells. After isoproterenol application with pacing at 1 Hz, 87.5% of CPVT-hiPSC-CMs developed DADs, compared to 30% of control-hiPSC-CMs (p<0.05). Pre-incubation with 10 μM S107, which stabilizes the closed state of the ryanodine receptor 2, significantly decreased the percentage of CPVT-hiPSC-CMs presenting DADs to 25% (p<0.05). Conclusions We recapitulated the electrophysiological features of CPVT-derived hiPSC-CMs using electrical pacing. The development of DADs in the presence of isoproterenol was significantly suppressed by S107. Our model provides a promising platform to study disease mechanisms and screen drugs.
Collapse
MESH Headings
- Action Potentials/drug effects
- Adult
- Animals
- Anti-Asthmatic Agents/chemistry
- Anti-Asthmatic Agents/pharmacology
- Anti-Asthmatic Agents/therapeutic use
- Calcium/metabolism
- Calreticulin/genetics
- Calreticulin/metabolism
- Calsequestrin/genetics
- Calsequestrin/metabolism
- Cell Differentiation/drug effects
- Cells, Cultured
- Electric Stimulation
- Fibroblasts/cytology
- Fibroblasts/metabolism
- Humans
- Induced Pluripotent Stem Cells/cytology
- Induced Pluripotent Stem Cells/metabolism
- Isoproterenol/pharmacology
- Mice
- Mice, Inbred NOD
- Mice, SCID
- Models, Biological
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/transplantation
- Ryanodine/pharmacology
- Ryanodine Receptor Calcium Release Channel/chemistry
- Ryanodine Receptor Calcium Release Channel/genetics
- Ryanodine Receptor Calcium Release Channel/metabolism
- Sarcoplasmic Reticulum Calcium-Transporting ATPases/genetics
- Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism
- Tachycardia, Ventricular/drug therapy
- Tachycardia, Ventricular/pathology
- Tachycardia, Ventricular/therapy
- Thiazepines/chemistry
- Thiazepines/pharmacology
- Thiazepines/therapeutic use
- Transplantation, Heterologous
Collapse
Affiliation(s)
- Kenichi Sasaki
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takeru Makiyama
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
- * E-mail: (TM); (Y. Yoshida)
| | - Yoshinori Yoshida
- Kyoto University iPS Cell Research and Application, Kyoto, Japan
- * E-mail: (TM); (Y. Yoshida)
| | - Yimin Wuriyanghai
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Tsukasa Kamakura
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Suguru Nishiuchi
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Mamoru Hayano
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takeshi Harita
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yuta Yamamoto
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hirohiko Kohjitani
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Sayako Hirose
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Jiarong Chen
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Mihoko Kawamura
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Seiko Ohno
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Hideki Itoh
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Ayako Takeuchi
- Department of Integrative and Systems Physiology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Satoshi Matsuoka
- Department of Integrative and Systems Physiology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Masaru Miura
- Division of Cardiology, Tokyo Metropolitan Children’s Medical Center, Tokyo, Japan
| | - Naokata Sumitomo
- Department of Pediatric Cardiology, Saitama Medical University International Medical Center, Saitama, Japan
| | - Minoru Horie
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Shinya Yamanaka
- Kyoto University iPS Cell Research and Application, Kyoto, Japan
| | - Takeshi Kimura
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| |
Collapse
|
15
|
Hartmann N, Pabel S, Herting J, Schatter F, Renner A, Gummert J, Schotola H, Danner BC, Maier LS, Frey N, Hasenfuss G, Fischer TH, Sossalla S. Antiarrhythmic effects of dantrolene in human diseased cardiomyocytes. Heart Rhythm 2016; 14:412-419. [PMID: 27650424 DOI: 10.1016/j.hrthm.2016.09.014] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Indexed: 01/27/2023]
Abstract
BACKGROUND Cardiac type 2 ryanodine receptors (RyR2s) play a pivotal role in cellular electrophysiology and contractility. Increased RyR2-mediated diastolic sarcoplasmic reticulum (SR) Ca2+ release is linked to heart failure (HF) and arrhythmias. Dantrolene, a drug used for the treatment of malignant hyperthermia, is known to stabilize RyRs in skeletal muscle. OBJECTIVE The purpose of this study was to investigate the effects of dantrolene on arrhythmogenic triggers and contractile function in human atrial fibrillation (AF) and HF cardiomyocytes (CM). METHODS Human CM were isolated from either patients with HF (ventricular) or patients with AF (atrial), and Ca2+ imaging, patch-clamp, or muscle strip experiments were performed. RESULTS After exposure to dantrolene, human atrial AF and left ventricular HF CM showed significant reductions in proarrhythmic SR Ca2+ spark frequency and diastolic SR Ca2+ leak. Moreover, dantrolene decreased the frequency of Ca2+ waves and spontaneous Ca2+ transients in HF CM. Patch-clamp experiments revealed that dantrolene significantly suppressed delayed afterdepolarizations in HF and AF CM. Importantly, dantrolene had no effect on action potential duration in AF or in HF CM. In addition, dantrolene had neutral effects on contractile force of human isometrically twitching ventricular HF trabeculae. CONCLUSION Our study showed that dantrolene beneficially influenced disrupted SR Ca2+ homeostasis in human HF and AF CM. Cellular arrhythmogenic triggers were potently suppressed by dantrolene, whereas action potential duration and contractility were not affected. As a clinically approved drug for the treatment of malignant hyperthermia, dantrolene may be a potential antiarrhythmic drug for patients with rhythm disorders and merits further clinical investigation.
Collapse
Affiliation(s)
- Nico Hartmann
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany
| | - Steffen Pabel
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany
| | - Jonas Herting
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany
| | - Felix Schatter
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany
| | - André Renner
- Department of Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Jan Gummert
- Department of Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany
| | - Hanna Schotola
- Department of Anesthesiology, Emergency and Intensive Care Medicine, Georg-August-University Göttingen, Göttingen, Germany
| | - Bernhard C Danner
- Department of Thoracic and Cardiovascular Surgery, Georg-August-University Göttingen, Göttingen, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Hospital Regensburg, Regensburg, Germany
| | - Norbert Frey
- Department of Internal Medicine III: Cardiology and Angiology, University of Kiel, Kiel, Germany; DZHK (German Center for Cardiovascular Research), partner site Göttingen, Göttingen, Germany
| | - Gerd Hasenfuss
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany; DZHK (German Center for Cardiovascular Research), partner site Göttingen, Göttingen, Germany
| | - Thomas H Fischer
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany
| | - Samuel Sossalla
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany; Department of Internal Medicine III: Cardiology and Angiology, University of Kiel, Kiel, Germany; DZHK (German Center for Cardiovascular Research), partner site Göttingen, Göttingen, Germany.
| |
Collapse
|
16
|
RyR2 QQ2958 Genotype and Risk of Malignant Ventricular Arrhythmias. Cardiol Res Pract 2016; 2016:2868604. [PMID: 26904356 PMCID: PMC4745938 DOI: 10.1155/2016/2868604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/05/2016] [Indexed: 11/21/2022] Open
Abstract
Ventricular arrhythmias are one of the most common causes of death in developed countries. The use of implantable cardiac defibrillators is the most effective treatment to prevent sudden cardiac death. To date, the ejection fraction is the only approved clinical variable used to determine suitability for defibrillator placement in subjects with heart failure. The purpose of this study was to assess whether genetic polymorphisms found in the ryanodine receptor type 2 (Q2958R) and histidine-rich calcium-binding protein (S96A) might serve as markers for arrhythmias. Genotyping was performed in 235 patients treated with defibrillator for primary and secondary prevention of arrhythmias. No significant association was found between the S96A polymorphism and arrhythmia onset, whereas the QQ2958 genotype in the ryanodine receptor gene was correlated with an increased risk of life-threatening arrhythmias. Concurrent stressor conditions, such as hypertension, seem to increase this effect. Our findings might help to better identify patients who could benefit from defibrillator implantation.
Collapse
|
17
|
Abstract
The ryanodine receptor/Ca2+ release channel plays a pivotal role in skeletal and cardiac muscle excitation-contraction coupling. Defective regulation leads to neuromuscular disorders and arrhythmogenic cardiac disease. This mini-review focuses on channel regulation through structural intra- and inter-subunit interactions and their implications in ryanodine receptor pathophysiology.
Collapse
|
18
|
FRET-based trilateration of probes bound within functional ryanodine receptors. Biophys J 2015; 107:2037-48. [PMID: 25418089 DOI: 10.1016/j.bpj.2014.09.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/08/2014] [Accepted: 09/19/2014] [Indexed: 02/05/2023] Open
Abstract
To locate the biosensor peptide DPc10 bound to ryanodine receptor (RyR) Ca(2+) channels, we developed an approach that combines fluorescence resonance energy transfer (FRET), simulated-annealing, cryo-electron microscopy, and crystallographic data. DPc10 is identical to the 2460-2495 segment within the cardiac muscle RyR isoform (RyR2) central domain. DPc10 binding to RyR2 results in a pathologically elevated Ca(2+) leak by destabilizing key interactions between the RyR2 N-terminal and central domains (unzipping). To localize the DPc10 binding site within RyR2, we measured FRET between five single-cysteine variants of the FK506-binding protein (FKBP) labeled with a donor probe, and DPc10 labeled with an acceptor probe (A-DPc10). Effective donor positions were calculated from simulated-annealing constrained by both the RyR cryo-EM map and the FKBP atomic structure docked to the RyR. FRET to A-DPc10 was measured in permeabilized cardiomyocytes via confocal microscopy, converted to distances, and used to trilaterate the acceptor locus within RyR. Additional FRET measurements between donor-labeled calmodulin and A-DPc10 were used to constrain the trilaterations. Results locate the DPc10 probe within RyR domain 3, ?35 Å from the previously docked N-terminal domain crystal structure. This multiscale approach may be useful in mapping other RyR sites of mechanistic interest within FRET range of FKBP.
Collapse
|
19
|
Tzimas C, Terrovitis J, Lehnart SE, Kranias EG, Sanoudou D. Calcium/calmodulin-dependent protein kinase II (CaMKII) inhibition ameliorates arrhythmias elicited by junctin ablation under stress conditions. Heart Rhythm 2015; 12:1599-610. [PMID: 25814413 PMCID: PMC4485547 DOI: 10.1016/j.hrthm.2015.03.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Indexed: 01/01/2023]
Abstract
BACKGROUND Aberrant calcium signaling is considered one of the key mechanisms contributing to arrhythmias, especially in the context of heart failure. In human heart failure, there is significant down-regulation of the sarcoplasmic reticulum (SR) protein junctin, and junctin deficiency in mice is associated with stress-induced arrhythmias. OBJECTIVE The purpose of this study was to determine whether the increased SR Ca(2+) leak and arrhythmias associated with junctin ablation may be associated with increased calcium/calmodulin-dependent protein kinase II (CaMKII) activity and phosphorylation of the cardiac ryanodine receptor (RyR2) and whether pharmacologic inhibition of CaMKII activity may prevent these arrhythmias. METHODS Using a combination of biochemical, cellular, and in vivo approaches, we tested the ability of KN-93 to reverse aberrant CaMKII phosphorylation of RyR2. Specifically, we performed protein phosphorylation analysis, in vitro cardiomyocyte contractility and Ca(2+) kinetics, and in vivo ECG analysis in junctin-deficient mice. RESULTS In the absence of junctin, RyR2 channels displayed CaMKII-dependent hyperphosphorylation. Notably, CaMKII inhibition by KN-93 reduced the in vivo incidence of stress-induced ventricular tachycardia by 65% in junctin null mice. At the cardiomyocyte level, KN-93 reduced the percentage of junctin null cells exhibiting spontaneous Ca(2+) aftertransients and aftercontractions under stress conditions by 35% and 37%, respectively. At the molecular level, KN-93 blunted the CaMKII-mediated hyperphosphorylation of RyR2 and phospholamban under stress conditions. CONCLUSION Our data suggest that CaMKII inhibition is effective in preventing arrhythmogenesis in the setting of junctin ablation through modulation of both SR Ca(2+) release and uptake. Thus, it merits further investigation as promising molecular therapy.
Collapse
Affiliation(s)
- Christos Tzimas
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - John Terrovitis
- 3rd Department of Cardiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Stephan E Lehnart
- Clinic of Cardiology & Pulmonology, University Medical Center Goettingen, Goettingen, Germany
| | - Evangelia G Kranias
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece; Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Despina Sanoudou
- Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece; Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece.
| |
Collapse
|
20
|
Murfitt L, Whiteley G, Iqbal MM, Kitmitto A. Targeting caveolin-3 for the treatment of diabetic cardiomyopathy. Pharmacol Ther 2015; 151:50-71. [PMID: 25779609 DOI: 10.1016/j.pharmthera.2015.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 03/09/2015] [Indexed: 12/21/2022]
Abstract
Diabetes is a global health problem with more than 550 million people predicted to be diabetic by 2030. A major complication of diabetes is cardiovascular disease, which accounts for over two-thirds of mortality and morbidity in diabetic patients. This increased risk has led to the definition of a diabetic cardiomyopathy phenotype characterised by early left ventricular dysfunction with normal ejection fraction. Here we review the aetiology of diabetic cardiomyopathy and explore the involvement of the protein caveolin-3 (Cav3). Cav3 forms part of a complex mechanism regulating insulin signalling and glucose uptake, processes that are impaired in diabetes. Further, Cav3 is key for stabilisation and trafficking of cardiac ion channels to the plasma membrane and so contributes to the cardiac action potential shape and duration. In addition, Cav3 has direct and indirect interactions with proteins involved in excitation-contraction coupling and so has the potential to influence cardiac contractility. Significantly, both impaired contractility and rhythm disturbances are hallmarks of diabetic cardiomyopathy. We review here how changes to Cav3 expression levels and altered relationships with interacting partners may be contributory factors to several of the pathological features identified in diabetic cardiomyopathy. Finally, the review concludes by considering ways in which levels of Cav3 may be manipulated in order to develop novel therapeutic approaches for treating diabetic cardiomyopathy.
Collapse
Affiliation(s)
- Lucy Murfitt
- Institute of Cardiovascular Sciences, Faculty of Medical and Human Sciences, University of Manchester, M13 9NT, UK
| | - Gareth Whiteley
- Institute of Cardiovascular Sciences, Faculty of Medical and Human Sciences, University of Manchester, M13 9NT, UK
| | - Mohammad M Iqbal
- Institute of Cardiovascular Sciences, Faculty of Medical and Human Sciences, University of Manchester, M13 9NT, UK
| | - Ashraf Kitmitto
- Institute of Cardiovascular Sciences, Faculty of Medical and Human Sciences, University of Manchester, M13 9NT, UK.
| |
Collapse
|
21
|
Van Petegem F. Ryanodine Receptors: Allosteric Ion Channel Giants. J Mol Biol 2015; 427:31-53. [DOI: 10.1016/j.jmb.2014.08.004] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 08/02/2014] [Accepted: 08/05/2014] [Indexed: 01/27/2023]
|
22
|
Lau K, Van Petegem F. Crystal structures of wild type and disease mutant forms of the ryanodine receptor SPRY2 domain. Nat Commun 2014; 5:5397. [DOI: 10.1038/ncomms6397] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 09/26/2014] [Indexed: 12/16/2022] Open
|
23
|
Borko Ľ, Bauerová-Hlinková V, Hostinová E, Gašperík J, Beck K, Lai FA, Zahradníková A, Ševčík J. Structural insights into the human RyR2 N-terminal region involved in cardiac arrhythmias. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:2897-912. [PMID: 25372681 PMCID: PMC4220973 DOI: 10.1107/s1399004714020343] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 09/10/2014] [Indexed: 01/11/2023]
Abstract
Human ryanodine receptor 2 (hRyR2) mediates calcium release from the sarcoplasmic reticulum, enabling cardiomyocyte contraction. The N-terminal region of hRyR2 (amino acids 1-606) is the target of >30 arrhythmogenic mutations and contains a binding site for phosphoprotein phosphatase 1. Here, the solution and crystal structures determined under near-physiological conditions, as well as a homology model of the hRyR2 N-terminal region, are presented. The N-terminus is held together by a unique network of interactions among its three domains, A, B and C, in which the central helix (amino acids 410-437) plays a prominent stabilizing role. Importantly, the anion-binding site reported for the mouse RyR2 N-terminal region is notably absent from the human RyR2. The structure concurs with the differential stability of arrhythmogenic mutations in the central helix (R420W, I419F and I419F/R420W) which are owing to disparities in the propensity of mutated residues to form energetically favourable or unfavourable contacts. In solution, the N-terminus adopts a globular shape with a prominent tail that is likely to involve residues 545-606, which are unresolved in the crystal structure. Docking the N-terminal domains into cryo-electron microscopy maps of the closed and open RyR1 conformations reveals C(α) atom movements of up to 8 Å upon channel gating, and predicts the location of the leucine-isoleucine zipper segment and the interaction site for spinophilin and phosphoprotein phosphatase 1 on the RyR surface.
Collapse
Affiliation(s)
- Ľubomír Borko
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Vladena Bauerová-Hlinková
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Eva Hostinová
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Juraj Gašperík
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Konrad Beck
- Cardiff University School of Dentistry, Heath Park, Cardiff CF14 4XY, Wales
| | - F. Anthony Lai
- Department of Cardiology, Wales Heart Research Institute, Cardiff University School of Medicine, Cardiff CF14 4XN, Wales
| | - Alexandra Zahradníková
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlárska 5, 833 34 Bratislava, Slovakia
| | - Jozef Ševčík
- Department of Biochemistry and Structural Biology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| |
Collapse
|
24
|
Fukuda M, Yamamoto T, Nishimura S, Kato T, Murakami W, Hino A, Ono M, Tateishi H, Oda T, Okuda S, Kobayashi S, Koseki N, Kyushiki H, Yano M. Enhanced binding of calmodulin to RyR2 corrects arrhythmogenic channel disorder in CPVT-associated myocytes. Biochem Biophys Res Commun 2014; 448:1-7. [DOI: 10.1016/j.bbrc.2014.03.152] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 03/31/2014] [Indexed: 11/29/2022]
|
25
|
Sedej S, Schmidt A, Denegri M, Walther S, Matovina M, Arnstein G, Gutschi EM, Windhager I, Ljubojević S, Negri S, Heinzel FR, Bisping E, Vos MA, Napolitano C, Priori SG, Kockskämper J, Pieske B. Subclinical abnormalities in sarcoplasmic reticulum Ca(2+) release promote eccentric myocardial remodeling and pump failure death in response to pressure overload. J Am Coll Cardiol 2013; 63:1569-79. [PMID: 24315909 DOI: 10.1016/j.jacc.2013.11.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/31/2013] [Accepted: 11/01/2013] [Indexed: 12/26/2022]
Abstract
OBJECTIVES This study sought to explore whether subclinical alterations of sarcoplasmic reticulum (SR) Ca(2+) release through cardiac ryanodine receptors (RyR2) aggravate cardiac remodeling in mice carrying a human RyR2(R4496C+/-) gain-of-function mutation in response to pressure overload. BACKGROUND RyR2 dysfunction causes increased diastolic SR Ca(2+) release associated with arrhythmias and contractile dysfunction in inherited and acquired cardiac diseases, such as catecholaminergic polymorphic ventricular tachycardia and heart failure (HF). METHODS Functional and structural properties of wild-type and catecholaminergic polymorphic ventricular tachycardia-associated RyR2(R4496C+/-) hearts were characterized under conditions of pressure overload induced by transverse aortic constriction (TAC). RESULTS Wild-type and RyR2(R4496C+/-) hearts had comparable structural and functional properties at baseline. After TAC, RyR2(R4496C+/-) hearts responded with eccentric hypertrophy, substantial fibrosis, ventricular dilation, and reduced fractional shortening, ultimately resulting in overt HF. RyR2(R4496C+/-)-TAC cardiomyocytes showed increased incidence of spontaneous SR Ca(2+) release events, reduced Ca(2+) transient peak amplitude, and SR Ca(2+) content as well as reduced SR Ca(2+)-ATPase 2a and increased Na(+)/Ca(2+)-exchanger protein expression. HF phenotype in RyR2(R4496C+/-)-TAC mice was associated with increased mortality due to pump failure but not tachyarrhythmic events. RyR2-stabilizer K201 markedly reduced Ca(2+) spark frequency in RyR2(R4496C+/-)-TAC cardiomyocytes. Mini-osmotic pump infusion of K201 prevented deleterious remodeling and improved survival in RyR2(R4496C+/-)-TAC mice. CONCLUSIONS The combination of subclinical congenital alteration of SR Ca(2+) release and pressure overload promoted eccentric remodeling and HF death in RyR2(R4496C+/-) mice, and pharmacological RyR2 stabilization prevented this deleterious interaction. These findings suggest potential clinical relevance for patients with acquired or inherited gain-of-function of RyR2-mediated SR Ca(2+) release.
Collapse
Affiliation(s)
- Simon Sedej
- Department of Cardiology, Medical University of Graz, Graz, Austria; Ludwig Boltzmann Institute for Translational Heart Failure Research, Graz, Austria.
| | - Albrecht Schmidt
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Marco Denegri
- IRCCS Salvatore Maugeri Foundation and Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Stefanie Walther
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Marinko Matovina
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Georg Arnstein
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Eva-Maria Gutschi
- Department of Cardiology, Medical University of Graz, Graz, Austria; Ludwig Boltzmann Institute for Translational Heart Failure Research, Graz, Austria
| | | | - Senka Ljubojević
- Department of Cardiology, Medical University of Graz, Graz, Austria; Ludwig Boltzmann Institute for Translational Heart Failure Research, Graz, Austria
| | - Sara Negri
- IRCCS Salvatore Maugeri Foundation and Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Frank R Heinzel
- Department of Cardiology, Medical University of Graz, Graz, Austria; Ludwig Boltzmann Institute for Translational Heart Failure Research, Graz, Austria
| | - Egbert Bisping
- Department of Cardiology, Medical University of Graz, Graz, Austria; Ludwig Boltzmann Institute for Translational Heart Failure Research, Graz, Austria
| | - Marc A Vos
- Department of Medical Physiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Carlo Napolitano
- IRCCS Salvatore Maugeri Foundation and Department of Molecular Medicine, University of Pavia, Pavia, Italy; Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York
| | - Silvia G Priori
- IRCCS Salvatore Maugeri Foundation and Department of Molecular Medicine, University of Pavia, Pavia, Italy; Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York
| | - Jens Kockskämper
- Institute of Pharmacology and Clinical Pharmacy, Philipps-University of Marburg, Marburg, Germany
| | - Burkert Pieske
- Department of Cardiology, Medical University of Graz, Graz, Austria; Ludwig Boltzmann Institute for Translational Heart Failure Research, Graz, Austria.
| |
Collapse
|
26
|
Stathopulos PB, Seo MD, Enomoto M, Amador FJ, Ishiyama N, Ikura M. Themes and variations in ER/SR calcium release channels: structure and function. Physiology (Bethesda) 2013; 27:331-42. [PMID: 23223627 DOI: 10.1152/physiol.00013.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Calcium (Ca(2+)) release from reticular stores is a vital regulatory signal in eukaryotes. Recent structural data on large NH(2)-terminal regions of IP(3)Rs and RyRs and their tetrameric arrangement in the full-length context reveal striking mechanistic similarities in Ca(2+) release channel function. A common ancestor found in unicellular genomes underscores the fundamentality of these elements to Ca(2+) release channels.
Collapse
Affiliation(s)
- Peter B Stathopulos
- Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | | | | | | | | | | |
Collapse
|
27
|
Okada H, Lai NC, Kawaraguchi Y, Liao P, Copps J, Sugano Y, Okada-Maeda S, Banerjee I, Schilling JM, Gingras AR, Asfaw EK, Suarez J, Kang SM, Perkins GA, Au CG, Israeli-Rosenberg S, Manso AM, Liu Z, Milner DJ, Kaufman SJ, Patel HH, Roth DM, Hammond HK, Taylor SS, Dillmann WH, Goldhaber JI, Ross RS. Integrins protect cardiomyocytes from ischemia/reperfusion injury. J Clin Invest 2013; 123:4294-308. [PMID: 24091324 DOI: 10.1172/jci64216] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 07/18/2013] [Indexed: 11/17/2022] Open
Abstract
Ischemic damage is recognized to cause cardiomyocyte (CM) death and myocardial dysfunction, but the role of cell-matrix interactions and integrins in this process has not been extensively studied. Expression of α7β1D integrin, the dominant integrin in normal adult CMs, increases during ischemia/reperfusion (I/R), while deficiency of β1 integrins increases ischemic damage. We hypothesized that the forced overexpression of integrins on the CM would offer protection from I/R injury. Tg mice with CM-specific overexpression of integrin α7β1D exposed to I/R had a substantial reduction in infarct size compared with that of α5β1D-overexpressing mice and WT littermate controls. Using isolated CMs, we found that α7β1D preserved mitochondrial membrane potential during hypoxia/reoxygenation (H/R) injury via inhibition of mitochondrial Ca2+ overload but did not alter H/R effects on oxidative stress. Therefore, we assessed Ca2+ handling proteins in the CM and found that β1D integrin colocalized with ryanodine receptor 2 (RyR2) in CM T-tubules, complexed with RyR2 in human and rat heart, and specifically bound to RyR2 amino acids 165-175. Integrins stabilized the RyR2 interdomain interaction, and this stabilization required integrin receptor binding to its ECM ligand. These data suggest that α7β1D integrin modifies Ca2+ regulatory pathways and offers a means to protect the myocardium from ischemic injury.
Collapse
|
28
|
Aiello EA, De Giusti VC. Regulation of the cardiac sodium/bicarbonate cotransporter by angiotensin II: potential Contribution to structural, ionic and electrophysiological myocardial remodelling. Curr Cardiol Rev 2013; 9:24-32. [PMID: 23116057 PMCID: PMC3584305 DOI: 10.2174/157340313805076340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 08/15/2012] [Accepted: 09/13/2012] [Indexed: 12/15/2022] Open
Abstract
The sodium/ bicarbonate cotransporter (NBC) is, with the Na+/H+ exchanger (NHE), an important alkalinizing mechanism that maintains cellular intracellular pH (pHi). In the heart exists at least three isoforms of NBC, one that promotes the co-influx of 1 molecule of Na+ per 1molecule of HCO3-(electroneutral isoform; nNBC) and two others that generates the co-influx of 1 molecule of Na+ per 2 molecules of HCO3- (electrogenic isoforms; eNBC). In addition, the eNBC generates an anionic repolarizing current that modulate the cardiac action potential (CAP), adding to such isoforms the relevance to modulate the electrophysiological function of the heart. Angiotensin II (Ang II) is one of the main hormones that regulate cardiac physiology. The alkalinizing mechanisms (NHE and NBC) are stimulated by Ang II, increasing pHi and intracellular Na+ concentration, which indirectly, due to the stimulation of the Na+/Ca2+ exchanger (NCX) operating in the reverse form, leads to an increase in the intracellular Ca2+ concentration. Interestingly, it has been shown that Ang II exhibits an opposite effect on NBC isoforms: it activates the nNBC and inhibits the eNBC. This inhibition generates a CAP prolongation, which could directly increase the intracellular Ca2+ concentration. The regulation of the intracellular Na+ and Ca2+ concentrations is crucial for the cardiac cellular physiology, but these ions are also involved in the development of cardiac hypertrophy and the damage produced by ischemia-reperfusion, suggesting a potential role of NBC in cardiac diseases.
Collapse
Affiliation(s)
- Ernesto Alejandro Aiello
- Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120, 1900, La Plata, Argentina.
| | | |
Collapse
|
29
|
Amador FJ, Stathopulos PB, Enomoto M, Ikura M. Ryanodine receptor calcium release channels: lessons from structure-function studies. FEBS J 2013; 280:5456-70. [PMID: 23413940 DOI: 10.1111/febs.12194] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/24/2013] [Accepted: 02/04/2013] [Indexed: 11/28/2022]
Abstract
Ryanodine receptors (RyRs) are the largest known ion channels. They are Ca(2+) release channels found primarily on the sarcoplasmic reticulum of myocytes. Several hundred mutations in RyRs are associated with skeletal or cardiomyocyte disease in humans. Many of these mutations can now be mapped onto the high resolution structures of individual RyR domains and on full-length tetrameric cryo-electron microscopy structures. A closely related Ca(2+) release channel, the inositol 1,4,5-trisphospate receptor (IP3 R), shows a conserved structural architecture at the N-terminus, suggesting that both channels evolved from an ancestral unicellular RyR/IP3 R. The functional insights provided by recent structural studies for both channels will aid in the development of rationale treatments for a myriad of Ca(2+)-signaled malignancies.
Collapse
Affiliation(s)
- Fernando J Amador
- Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Canada
| | | | | | | |
Collapse
|
30
|
Sacherer M, Sedej S, Wakuła P, Wallner M, Vos MA, Kockskämper J, Stiegler P, Sereinigg M, von Lewinski D, Antoons G, Pieske BM, Heinzel FR. JTV519 (K201) reduces sarcoplasmic reticulum Ca²⁺ leak and improves diastolic function in vitro in murine and human non-failing myocardium. Br J Pharmacol 2013; 167:493-504. [PMID: 22509897 DOI: 10.1111/j.1476-5381.2012.01995.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Ca²⁺ leak from the sarcoplasmic reticulum (SR) via ryanodine receptors (RyR2s) contributes to cardiomyocyte dysfunction. RyR2 Ca²⁺ leak has been related to RyR2 phosphorylation. In these conditions, JTV519 (K201), a 1,4-benzothiazepine derivative and multi-channel blocker, stabilizes RyR2s and decrease SR Ca²⁺ leak. We investigated whether JTV519 stabilizes RyR2s without increasing RyR2 phosphorylation in mice and in non-failing human myocardium and explored underlying mechanisms. EXPERIMENTAL APPROACH SR Ca²⁺ leak was induced by ouabain in murine cardiomyocytes. [Ca²⁺]-transients, SR Ca²⁺ load and RyR2-mediated Ca²⁺ leak (sparks/waves) were quantified, with or without JTV519 (1 µmol·L⁻¹). Contribution of Ca²⁺ -/calmodulin-dependent kinase II (CaMKII) was assessed by KN-93 and Western blot (RyR2-Ser(2814) phosphorylation). Effects of JTV519 on contractile force were investigated in non-failing human ventricular trabeculae. KEY RESULTS Ouabain increased systolic and diastolic cytosolic [Ca²⁺](i) , SR [Ca²⁺], and SR Ca²⁺ leak (Ca²⁺ spark (SparkF) and Ca²⁺ wave frequency), independently of CaMKII and RyR-Ser(2814) phosphorylation. JTV519 decreased SparkF but also SR Ca²⁺ load. At matched SR [Ca²⁺], Ca²⁺ leak was significantly reduced by JTV519, but it had no effect on fractional Ca²⁺ release or Ca²⁺ wave propagation velocity. In human muscle, JTV519 was negatively inotropic at baseline but significantly enhanced ouabain-induced force and reduced its deleterious effects on diastolic function. CONCLUSIONS AND IMPLICATIONS JTV519 was effective in reducing SR Ca²⁺ leak by specifically regulating RyR2 opening at diastolic [Ca²⁺](i) in the absence of increased RyR2 phosphorylation at Ser(2814) , extending the potential use of JTV519 to conditions of acute cellular Ca²⁺ overload.
Collapse
Affiliation(s)
- M Sacherer
- Division of Cardiology, Medical University of Graz, Austria
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Oda T, Yang Y, Nitu FR, Svensson B, Lu X, Fruen BR, Cornea RL, Bers DM. In cardiomyocytes, binding of unzipping peptide activates ryanodine receptor 2 and reciprocally inhibits calmodulin binding. Circ Res 2012; 112:487-97. [PMID: 23233753 DOI: 10.1161/circresaha.111.300290] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE One hypothesis for elevated Ca(2+) leak through cardiac ryanodine receptors (ryanodine receptor 2 [RyR2]) in heart failure is interdomain unzipping that can enhance aberrant channel activation. A peptide (domain peptide corresponding to RyR2 residues 2460-2495 [DPc10]) corresponding to RyR2 central domain residues 2460-2495 recapitulates this arrhythmogenic RyR2 leakiness by unzipping N-terminal and central domains. Calmodulin (CaM) and FK506-binding protein (FKBP12.6) bind to RyR2 and stabilize the closed channel. Little is known about DPc10 binding to the RyR2 and how that may interact with binding (and effects) of CaM and FKBP12.6 to RyR2. OBJECTIVE To measure, directly in cardiac myocytes, the kinetics and binding affinity of DPc10 to RyR2 and how that affects RyR2 interaction with FKBP12.6 and CaM. METHODS AND RESULTS We used permeabilized rat ventricular myocytes and fluorescently labeled DPc10, FKBP12.6, and CaM. DPc10 access to its binding site is extremely slow in resting RyR2 but is accelerated by promoting RyR opening or unzipping (by unlabeled DPc10). RyR2-bound CaM (but not FKBP12.6) drastically slowed DPc10 binding. Conversely, DPc10 binding significantly reduced CaM (but not FKBP12.6) binding to the RyR2. Fluorescence resonance energy transfer measurements indicate that DPc10-binding and CaM-binding sites are separate and allow triangulation of the structural DPc10 binding locus on RyR2 vs FKBP12.6-binding and CaM-binding sites. CONCLUSIONS DPc10-RyR2 binding is sterically limited by the resting zipped RyR2 state. CaM binding to RyR2 stabilizes this zipped state, whereas RyR2 activation or prebound DPc10 enhances DPc10 access. DPc10-binding and CaM-binding sites are distinct but are allosterically interacting RyR2 sites. Neither DPc10 nor FKBP12.6 influences RyR2 binding of the other.
Collapse
Affiliation(s)
- Tetsuro Oda
- Department of Pharmacology, University of California, Davis, CA 95616, USA
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Tencerová B, Zahradníková A, Gaburjáková J, Gaburjáková M. Luminal Ca2+ controls activation of the cardiac ryanodine receptor by ATP. ACTA ACUST UNITED AC 2012; 140:93-108. [PMID: 22851674 PMCID: PMC3409101 DOI: 10.1085/jgp.201110708] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The synergic effect of luminal Ca2+, cytosolic Ca2+, and cytosolic adenosine triphosphate (ATP) on activation of cardiac ryanodine receptor (RYR2) channels was examined in planar lipid bilayers. The dose–response of RYR2 gating activity to ATP was characterized at a diastolic cytosolic Ca2+ concentration of 100 nM over a range of luminal Ca2+ concentrations and, vice versa, at a diastolic luminal Ca2+ concentration of 1 mM over a range of cytosolic Ca2+ concentrations. Low level of luminal Ca2+ (1 mM) significantly increased the affinity of the RYR2 channel for ATP but without substantial activation of the channel. Higher levels of luminal Ca2+ (8–53 mM) markedly amplified the effects of ATP on the RYR2 activity by selectively increasing the maximal RYR2 activation by ATP, without affecting the affinity of the channel to ATP. Near-diastolic cytosolic Ca2+ levels (<500 nM) greatly amplified the effects of luminal Ca2+. Fractional inhibition by cytosolic Mg2+ was not affected by luminal Ca2+. In models, the effects of luminal and cytosolic Ca2+ could be explained by modulation of the allosteric effect of ATP on the RYR2 channel. Our results suggest that luminal Ca2+ ions potentiate the RYR2 gating activity in the presence of ATP predominantly by binding to a luminal site with an apparent affinity in the millimolar range, over which local luminal Ca2+ likely varies in cardiac myocytes.
Collapse
Affiliation(s)
- Barbora Tencerová
- Institute of Molecular Physiology and Genetics, Centre of Excellence for Cardiovascular Research, Slovak Academy of Sciences, 833 34 Bratislava, Slovak Republic
| | | | | | | |
Collapse
|
33
|
ZHANG YANMIN, WU JINGJING, JEEVARATNAM KAMALAN, KING JAMESH, GUZADHUR LAILA, REN XIAOLEI, GRACE ANDREWA, LEI MING, HUANG CHRISTOPHERLH, FRASER JAMESA. Conduction Slowing Contributes to Spontaneous Ventricular Arrhythmias in Intrinsically Active Murine RyR2-P2328S
Hearts. J Cardiovasc Electrophysiol 2012; 24:210-8. [DOI: 10.1111/jce.12015] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
34
|
Hino A, Yano M, Kato T, Fukuda M, Suetomi T, Ono M, Murakami W, Susa T, Okuda S, Doi M, Kobayashi S, Yamamoto T, Koseki N, Kyushiki H, Ikemoto N, Matsuzaki M. Enhanced binding of calmodulin to the ryanodine receptor corrects contractile dysfunction in failing hearts. Cardiovasc Res 2012; 96:433-43. [PMID: 22893680 DOI: 10.1093/cvr/cvs271] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIMS The channel function of the cardiac ryanodine receptor (RyR2) is modulated by calmodulin (CaM). However, the involvement of CaM in aberrant Ca(2+) release in diseased hearts remains unclear. Here, we investigated the pathogenic role of defective CaM binding to the RyR2 in the channel dysfunction associated with heart failure. METHODS AND RESULTS The involvement of CaM in aberrant Ca(2+) release was assessed in normal and pacing-induced failing canine hearts. The apparent affinity of CaM for RyR2 was considerably lower in failing sarcoplasmic reticulum (SR) compared with normal SR. Thus, the amount of CaM bound to RyR2 was markedly decreased in failing myocytes. Expression of the CaM isoform Gly-Ser-His-CaM (GSH-CaM), which has much higher binding affinity than wild-type CaM for RyR1, restored normal CaM binding to RyR2 in both SR and myocytes of failing hearts. The Ca(2+) spark frequency (SpF) was markedly higher and the SR Ca(2+) content was lower in failing myocytes compared with normal myocytes. The incorporation of GSH-CaM into the failing myocytes corrected the aberrant SpF and SR Ca(2+) content to normal levels. CONCLUSION Reduced CaM binding to RyR2 seems to play a critical role in the pathogenesis of aberrant Ca(2+) release in failing hearts. Correction of the reduced CaM binding to RyR2 stabilizes the RyR2 channel function and thereby restores normal Ca(2+) handling and contractile function to failing hearts.
Collapse
Affiliation(s)
- Akihiro Hino
- Division of Cardiology, Department of Medicine and Clinical Science, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Bito V, Biesmans L, Gellen B, Antoons G, Macquaide N, Rouet-Benzineb P, Pezet M, Mercadier JJ, Sipido KR. FKBP12.6 overexpression does not protect against remodelling after myocardial infarction. Exp Physiol 2012; 98:134-48. [PMID: 22689442 DOI: 10.1113/expphysiol.2011.064089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Reducing the open probability of the ryanodine receptor (RyR) has been proposed to have beneficial effects in heart failure. We investigated whether conditional FKBP12.6 overexpression at the time of myocardial infarction (MI) could improve cardiac remodelling and cell Ca(2+) handling. Wild-type (WT) mice and mice overexpressing FKBP12.6 (Tg) were studied on average 7.5 ± 0.2 weeks after MI and compared with sham-operated mice for in vivo, myocyte function and remodelling. At baseline, unloaded cell shortening in Tg was not different from WT. The [Ca(2+)](i) transient amplitude was similar, but sarcoplasmic reticulum (SR) Ca(2+) content was larger in Tg, suggesting reduced fractional release. Spontaneous spark frequency was similar despite the increased SR Ca(2+) content, consistent with a reduced RyR channel open probability in Tg. After MI, left ventricular dilatation and myocyte hypertrophy were present in both groups, but more pronounced in Tg. Cell shortening amplitude was unchanged with MI in WT, but increased with MI in Tg. The amplitude of the [Ca(2+)](i) transient was not affected by MI in either genotype, but time to peak was increased; this was most pronounced in Tg. The SR Ca(2+) content and Na(+)- Ca(2+) exchanger function were not affected by MI. Spontaneous spark frequency was increased significantly after MI in Tg, and larger than in WT (at 4 Hz, 2.6 ± 0.4 sparks (100 μm)(-1) s(-1) in Tg MI versus 1.6 ± 0.2 sparks (100 μm)(-1) s(-1) in WT MI; P < 0.05). We conclude that FKPB12.6 overexpression can effectively reduce RyR open probability with maintained cardiomyocyte contraction. However, this approach appears insufficient to prevent and reduce post-MI remodelling, indicating that additional pathways may need to be targeted.
Collapse
Affiliation(s)
- Virginie Bito
- Laboratory of Experimental Cardiology, University of Leuven, Belgium.
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Kelly A, Elliott EB, Matsuda R, Kaneko N, Smith GL, Loughrey CM. The effect of K201 on isolated working rabbit heart mechanical function during pharmacologically induced Ca2+ overload. Br J Pharmacol 2012; 165:1068-83. [PMID: 21658026 DOI: 10.1111/j.1476-5381.2011.01531.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Reduced cardiac contractility has been associated with disrupted myocardial Ca(2+) signalling. The 1,4 benzothiazepine K201 (JTV-519) acts on several Ca(2+) handling proteins and improves cardiac contractility in vivo in a variety of animal models of myocardial dysfunction. However, it is unclear whether this improvement depends on the systemic effects of K201 or if K201 reverses the effects of Ca(2+) dysregulation, regardless of the cause. EXPERIMENTAL APPROACH The effect of K201 on cardiac mechanical function was assessed in isolated working hearts from adult rabbits, using a ventricular pressure-volume catheter. In separate experiments, the effect of K201 was investigated in hearts following pharmacologically induced Ca(2+) overload using elevated extracellular [Ca(2+) ] ([Ca(2+) ](o) ) and β-adrenoceptor stimulation. KEY RESULTS K201 induced a concentration-dependent decline in systolic function (peak pressure, dP/dt(max) and preload recruitable stroke work), lusitropy (reduced dP/dt(min) and increased end diastolic pressure) and stroke volume, independent of decreased heart rate. In separate experiments, mechanical function in hearts exposed to 4.5 mmol·L(-1) [Ca(2+) ](o) and 150 nmol·L(-1) isoprenaline declined until cessation of aortic flow (in 6 out of 11 hearts). However, all hearts perfused with the addition of 1 µmol·L(-1) K201 maintained aortic flow and demonstrated significantly improved peak systolic pressures, dP/dt(max) and dP/dt(min) . CONCLUSIONS AND IMPLICATIONS K201 significantly improved mechanical function of the heart during Ca(2+) overload. This suggests that K201 can limit the detrimental effects of elevated intracellular Ca(2+) and exert beneficial effects on cardiac contractile function, independent of systemic effects previously observed in vivo.
Collapse
Affiliation(s)
- A Kelly
- Institute of Cardiovascular & Medical Sciences, University of Glasgow, Glasgow, UK
| | | | | | | | | | | |
Collapse
|
37
|
Structural and functional conservation of key domains in InsP3 and ryanodine receptors. Nature 2012; 483:108-12. [PMID: 22286060 PMCID: PMC3378505 DOI: 10.1038/nature10751] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Accepted: 12/02/2011] [Indexed: 01/20/2023]
Abstract
Inositol 1,4,5-trisphosphate receptors (InsP3R) and ryanodine receptors (RyR) are tetrameric intracellular Ca2+ channels1. For each, the pore is formed by C-terminal transmembrane domains and regulated by signals detected by the large cytosolic structures. InsP3R gating is initiated by InsP3 binding to the InsP3-binding core (IBC, residues 224-604 of InsP3R1)2 and it requires the suppressor domain (SD, residues 1-223)2-8. We present structures of the N-terminal region (NT) of InsP3R1 with (3.6 Å) and without (3.0 Å) InsP3 bound. The arrangement of the three NT domains, the SD, IBC-β and IBC-α, identifies two discrete interfaces (α and β) between the IBC and SD. Similar interfaces occur between equivalent domains (A, B and C) in RyR19. The orientations of the three domains docked into a tetrameric structure of InsP3R10 and of the ABC domains in RyR9 are remarkably similar. The importance of the α-interface for activation of InsP3R and RyR is confirmed by mutagenesis and, for RyR, by disease-causing mutations9,11,12. InsP3 causes partial closure of the clam-like IBC, disrupting the β-interface and pulling the SD towards the IBC. This reorients an exposed SD loop (HS-loop) that is essential for InsP3R activation7. The loop is conserved in RyR and includes mutations associated with malignant hyperthermia and central core disease9,11,12. The HS-loop interacts with an adjacent NT, suggesting that activation re-arranges inter-subunit interactions. The A-domain of RyR functionally replaced the SD in a full-length InsP3R, and an InsP3R in which its C-terminal transmembrane region was replaced by that from RyR1 was gated by InsP3 and blocked by ryanodine. Activation mechanisms are conserved between InsP3R and RyR. Allosteric modulation of two similar domain interfaces within an N-terminal subunit re-orients the first domain (SD or A-domain), allowing it, via interactions of the second domain of an adjacent subunit (IBC-β or B-domain), to gate the pore.
Collapse
|
38
|
Jung CB, Moretti A, Mederos y Schnitzler M, Iop L, Storch U, Bellin M, Dorn T, Ruppenthal S, Pfeiffer S, Goedel A, Dirschinger RJ, Seyfarth M, Lam JT, Sinnecker D, Gudermann T, Lipp P, Laugwitz KL. Dantrolene rescues arrhythmogenic RYR2 defect in a patient-specific stem cell model of catecholaminergic polymorphic ventricular tachycardia. EMBO Mol Med 2012; 4:180-91. [PMID: 22174035 PMCID: PMC3376852 DOI: 10.1002/emmm.201100194] [Citation(s) in RCA: 240] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 12/01/2011] [Accepted: 12/05/2011] [Indexed: 12/23/2022] Open
Abstract
Coordinated release of calcium (Ca2+) from the sarcoplasmic reticulum (SR) through cardiac ryanodine receptor (RYR2) channels is essential for cardiomyocyte function. In catecholaminergic polymorphic ventricular tachycardia (CPVT), an inherited disease characterized by stress-induced ventricular arrhythmias in young patients with structurally normal hearts, autosomal dominant mutations in RYR2 or recessive mutations in calsequestrin lead to aberrant diastolic Ca2+ release from the SR causing arrhythmogenic delayed after depolarizations (DADs). Here, we report the generation of induced pluripotent stem cells (iPSCs) from a CPVT patient carrying a novel RYR2 S406L mutation. In patient iPSC-derived cardiomyocytes, catecholaminergic stress led to elevated diastolic Ca2+ concentrations, a reduced SR Ca2+ content and an increased susceptibility to DADs and arrhythmia as compared to control myocytes. This was due to increased frequency and duration of elementary Ca2+ release events (Ca2+ sparks). Dantrolene, a drug effective on malignant hyperthermia, restored normal Ca2+ spark properties and rescued the arrhythmogenic phenotype. This suggests defective inter-domain interactions within the RYR2 channel as the pathomechanism of the S406L mutation. Our work provides a new in vitro model to study the pathogenesis of human cardiac arrhythmias and develop novel therapies for CPVT.
Collapse
Affiliation(s)
- Christian B Jung
- Klinikum rechts der Isar, Technische Universität München, I. Medizinische Klinik, Kardiologie, München, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Thomas NL, Williams AJ. Pharmacology of ryanodine receptors and Ca2+-induced Ca2+ release. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/wmts.34] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
40
|
Techniques and Methodologies to Study the Ryanodine Receptor at the Molecular, Subcellular and Cellular Level. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:183-215. [DOI: 10.1007/978-94-007-2888-2_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
41
|
Abstract
The Ca(2) (+) signals evoked by inositol 1,4,5-trisphosphate (IP(3)) are built from elementary Ca(2) (+) release events involving progressive recruitment of IP(3) receptors (IP(3)R), intracellular Ca(2) (+) channels that are expressed in almost all animal cells. The smallest events ('blips') result from opening of single IP(3)R. Larger events ('puffs') reflect the near-synchronous opening of a small cluster of IP(3)R. These puffs become more frequent as the stimulus intensity increases and they eventually trigger regenerative Ca(2) (+) waves that propagate across the cell. This hierarchical recruitment of IP(3)R is important in allowing Ca(2) (+) signals to be delivered locally to specific target proteins or more globally to the entire cell. Co-regulation of IP(3)R by Ca(2) (+) and IP(3), the ability of a single IP(3)R rapidly to mediate a large efflux of Ca(2) (+) from the endoplasmic reticulum, and the assembly of IP(3)R into clusters are key features that allow IP(3)R to propagate Ca(2) (+) signals regeneratively. We review these properties of IP(3)R and the structural basis of IP(3)R behavior.
Collapse
Affiliation(s)
- Colin W Taylor
- Department of Pharmacology, Tennis Court Road, CB2 1PD, Cambridge, UK,
| | | |
Collapse
|
42
|
Pamuru PR, Maithili DVN, Mohiuddin K, Calambur N, Nallari P. Novel mutations in arrhythmogenic right ventricular cardiomyopathy from Indian population. INDIAN JOURNAL OF HUMAN GENETICS 2011; 17:70-6. [PMID: 22090716 PMCID: PMC3214321 DOI: 10.4103/0971-6866.86182] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive condition with right ventricular myocardium being replaced by fibro-fatty tissue. The spectrum of the expression may range from benign palpitations to the most malignant sudden death. Most of the mutations identified for the condition are localized in desmosomal proteins although three other nondesmosomal genes (cardiac ryanodine receptor-2, TGF-β3, and TMEM43) have also been implicated in ARVC. Both desmosomal and nondesmosomal genes were screened in a set of patients from local population. MATERIALS AND METHODS: A set of 34 patients from local population were included in this study. Diagnosis was based on the criteria proposed by task force of European Society of Cardiology/International Society and Federation of Cardiology. Polymerase chain reaction-based single-strand conformation polymorphism analysis was carried out, and samples with abnormal band pattern were commercially sequenced. RESULTS: Screening of cardiac ryanodine receptor revealed an insertion of a base in the intronic region of exon-28 in a patient, leading to a creation of a cryptic splice site. Screening of plakohilin-2 for mutations revealed an abnormal band pattern in three patients. Two of them had similar abnormal band pattern for exon-3.1. Sequencing revealed a novel 2 base pair deletion (433_434 delCT), which would lead to premature truncation of the protein (L145EfsX8). Another patient showed abnormal band pattern for exon-3.2 and sequencing revealed a missense mutation C792T leading to amino acid change P244L, in N-terminal, and this substitution may cause disturbances in the various protein–protein interactions. CONCLUSION: This study reports novel cardiac ryanodine receptor (RyR-2) mutations and Pkp-2 for the first time from Indian population.
Collapse
Affiliation(s)
- Pranathi Rao Pamuru
- Department of Genetics, Osmania University, Hyderabad, Andhra Pradesh, India
| | | | | | | | | |
Collapse
|
43
|
Aberrant interaction of calmodulin with the ryanodine receptor develops hypertrophy in the neonatal cardiomyocyte. Biochem J 2011; 438:379-87. [PMID: 21649588 DOI: 10.1042/bj20110203] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have shown previously that the inter-domain interaction between the two domains of RyR (ryanodine receptor), CaMBD [CaM (calmodulin)-binding domain] and CaMLD (CaM-like domain), activates the Ca(2+) channel, and this process is called activation-link formation [Gangopadhyay and Ikemoto (2008) Biochem. J. 411, 415-423]. Thus CaM that is bound to CaMBD is expected to interfere the activation-link formation, thereby stabilizing the closed state of the channel under normal conditions. In the present paper, we report that, upon stimulation of neonatal cardiomyocytes with the pro-hypertrophy agonist ET-1 (endothelin-1), CaM dissociates from the RyR, which induces a series of intracellular events: increased frequency of Ca(2+) transients, translocation of the signalling molecules CaM, CaMKII (CaM kinase II) and the transcription factor NFAT (nuclear factor of activated T-cells) to the nucleus. These events then lead to the development of hypertrophy. Importantly, an anti-CaMBD antibody that interferes with activation-link formation prevented all of these intracellular events triggered by ET-1 and prevented the development of hypertrophy. These results indicate that the aberrant formation of the activation link between CaMBD and CaMLD of RyR is a key step in the development of hypertrophy in cultured cardiomyocytes.
Collapse
|
44
|
Lobo PA, Kimlicka L, Tung CC, Van Petegem F. The deletion of exon 3 in the cardiac ryanodine receptor is rescued by β strand switching. Structure 2011; 19:790-8. [PMID: 21645850 DOI: 10.1016/j.str.2011.03.016] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 02/17/2011] [Accepted: 03/22/2011] [Indexed: 11/29/2022]
Abstract
Mutations in the cardiac Ryanodine Receptor (RYR2) are linked to triggered arrhythmias. Removal of exon 3 results in a severe form of catecholaminergic polymorphic ventricular tachycardia (CPVT). This exon encodes secondary structure elements that are crucial for folding of the N-terminal domain (NTD), raising the question of why the deletion is neither lethal nor confers a loss of function. We determined the 2.3 Å crystal structure of the NTD lacking exon 3. The removal causes a structural rescue whereby a flexible loop inserts itself into the β trefoil domain and increases thermal stability. The exon 3 deletion is not tolerated in the corresponding RYR1 domain. The rescue shows a novel mechanism by which RYR2 channels can adjust their Ca²⁺ release properties through altering the structure of the NTD. Despite the rescue, the deletion affects interfaces with other RYR2 domains. We propose that relative movement of the NTD is allosterically coupled to the pore region.
Collapse
Affiliation(s)
- Paolo A Lobo
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, room 2.320, Vancouver, BC V6T1Z3, Canada
| | | | | | | |
Collapse
|
45
|
Varró A, Baczkó I. Cardiac ventricular repolarization reserve: a principle for understanding drug-related proarrhythmic risk. Br J Pharmacol 2011; 164:14-36. [PMID: 21545574 PMCID: PMC3171857 DOI: 10.1111/j.1476-5381.2011.01367.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 02/22/2011] [Accepted: 03/02/2011] [Indexed: 12/11/2022] Open
Abstract
Cardiac repolarization abnormalities can be caused by a wide range of cardiac and non-cardiac compounds and may lead to the development of life-threatening Torsades de Pointes (TdP) ventricular arrhythmias. Drug-induced torsades de pointes is associated with unexpected and unexplained sudden cardiac deaths resulting in the withdrawal of several compounds in the past. To better understand the mechanism of such unexpected sudden cardiac deaths, the concept of repolarization reserve has recently emerged. According to this concept, pharmacological, congenital or acquired impairment of one type of transmembrane ion channel does not necessarily result in excessive repolarization changes because other repolarizing currents can take over and compensate. In this review, the major factors contributing to repolarization reserve are discussed in the context of their clinical significance in physiological and pathophysiological conditions including drug administration, genetic defects, heart failure, diabetes mellitus, gender, renal failure, hypokalaemia, hypothyroidism and athletes' sudden deaths. In addition, pharmacological support of repolarization reserve as a possible therapeutic option is discussed. Some methods for the quantitative estimation of repolarization reserve are also recommended. It is concluded that repolarization reserve should be considered by safety pharmacologists to better understand, predict and prevent previously unexplained drug-induced sudden cardiac deaths.
Collapse
Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary.
| | | |
Collapse
|
46
|
Two candidates at the heart of dysfunction: The ryanodine receptor and calcium/calmodulin protein kinase II as potential targets for therapeutic intervention—An in vivo perspective. Pharmacol Ther 2011; 131:204-20. [DOI: 10.1016/j.pharmthera.2011.02.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 02/17/2011] [Indexed: 11/19/2022]
|
47
|
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic disease occurring in patients with a structurally normal heart: the disease is characterized by life-threatening arrhythmias elicited by stress and emotion. In 2001, the ryanodine receptor was identified as the gene that is linked to CPVT; shortly thereafter, cardiac calsequestrin was implicated in the recessive form of the same disease. It became clear that abnormalities in intracellular Ca(2+) regulation could profoundly disrupt the electrophysiological properties of the heart. In this article, we discuss the molecular basis of the disease and the pathophysiological mechanisms that are impacting clinical diagnosis and management of affected individuals. As of today, the interaction between basic scientists and clinicians to understand CPVT and identify new therapeutic strategies is one of the most compelling examples of the importance of translational research in cardiology.
Collapse
Affiliation(s)
- Silvia G Priori
- Molecular Cardiology Laboratories, IRCCS Fondazione Salvatore Maugeri, Via Maugeri 10/10A, Pavia, Italy.
| | | |
Collapse
|
48
|
Zhang GL, Dai DZ, Xi T, Cong XD, Zhang Y, Dai Y. Isoproterenol-induced FKBP12.6/12 downregulation is modulated by ETA and ETB receptors and reversed by argirhein, a derivative of rhein. Acta Pharmacol Sin 2011; 32:223-9. [PMID: 21293474 DOI: 10.1038/aps.2010.177] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AIM To investigate which endothelin receptors mediated isoproterenol (ISO)-induced downregulation of FKBP12.6/12 in cardiomyocytes and study whether argirhein, a novel compound containing rhein and L-arginine that has anti-inflammatory activity, could reverse the downregulation of FKBP12.6/12 induced by ISO. METHODS Neonatal rat cardiomyocytes were incubated with ISO to downregulate FKBP12.6/12. Then the cells were treated with a selective ET(A) blocker (PD156707) and a ET(B) blocker (IRL1038), a dual ET(A)/ET(B) antagonist (CPU0213), and argirhein, respectively. FKBP12.6/12 expression was assayed by RT-PCR, Western blot, and immunocytochemistry. RESULTS The expression of FKBP12.6 mRNA was reduced by 37.7% (P<0.01) and 28.9% (P<0.05) relative to the control by ISO 1 and 0.1 μmol/L, respectively, but no response to ISO 0.01 μmol/L was observed in vitro. FKBP12.6/12 protein expression was reduced by 47.2% (P<0.01) and 37.8% (P<0.05) by ISO 1 and 0.1 μmol/L, respectively. This decrease was reversed significantly by PD156707, or IRL1038, and CPU0213. CPU0213 was more potent than either PD156707 or IRL-1038. Argirhein 10 μmol/L blunted the downregulation of FKBP12.6/12 by ISO, as demonstrated by the rising mRNA and protein levels and by the fluorescent density of the ISO-incubated cardiomyocytes. CONCLUSION In cardiomyocytes, the ISO induced downregulation of FKBP12.6/12 is modulated by both ET(A) and ET(B). A new compound, argirein, reversed the down-regulation of FKBP12.6/12 expression in myocardial cells stimulated with ISO.
Collapse
|
49
|
Taylor CW, Tovey SC. IP(3) receptors: toward understanding their activation. Cold Spring Harb Perspect Biol 2010; 2:a004010. [PMID: 20980441 DOI: 10.1101/cshperspect.a004010] [Citation(s) in RCA: 170] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP(3)R) and their relatives, ryanodine receptors, are the channels that most often mediate Ca(2+) release from intracellular stores. Their regulation by Ca(2+) allows them also to propagate cytosolic Ca(2+) signals regeneratively. This brief review addresses the structural basis of IP(3)R activation by IP(3) and Ca(2+). IP(3) initiates IP(3)R activation by promoting Ca(2+) binding to a stimulatory Ca(2+)-binding site, the identity of which is unresolved. We suggest that interactions of critical phosphate groups in IP(3) with opposite sides of the clam-like IP(3)-binding core cause it to close and propagate a conformational change toward the pore via the adjacent N-terminal suppressor domain. The pore, assembled from the last pair of transmembrane domains and the intervening pore loop from each of the four IP(3)R subunits, forms a structure in which a luminal selectivity filter and a gate at the cytosolic end of the pore control cation fluxes through the IP(3)R.
Collapse
Affiliation(s)
- Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, United Kingdom.
| | | |
Collapse
|
50
|
Kobayashi S, Yano M, Uchinoumi H, Suetomi T, Susa T, Ono M, Xu X, Tateishi H, Oda T, Okuda S, Doi M, Yamamoto T, Matsuzaki M. Dantrolene, a therapeutic agent for malignant hyperthermia, inhibits catecholaminergic polymorphic ventricular tachycardia in a RyR2(R2474S/+) knock-in mouse model. Circ J 2010; 74:2579-84. [PMID: 20944434 DOI: 10.1253/circj.cj-10-0680] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Dantrolene, a specific agent for the treatment of malignant hyperthermia, was found to inhibit Ca(2+) leak through not only the skeletal ryanodine receptor (RyR1), but also the cardiac ryanodine receptor (RyR2) by correcting the defective inter-domain interaction between N-terminal (1-619 amino acid) and central (2,000-2,500 amino acid) domains of RyRs. Here, the in vivo anti-arrhythmic effect of dantrolene in a human catecholaminergic polymorphic ventricular tachycardia (CPVT)-associated RyR2(R2474S/+) knock-in (KI) mouse model was investigated. METHODS AND RESULTS ECG was monitored in KI mice (n=6) and wild-type (WT) mice (n=6), before and after an injection of epinephrine (1.0mg/kg) or on exercise using a treadmill. In all KI (but not WT) mice, bi-directional ventricular tachycardia (VT) was induced after an injection of epinephrine or on exercise. Pre-treatment with dantrolene (for 7-10 days) significantly inhibited the inducible VT (P<0.01). In KI cardiomyocytes, Ca(2+) spark frequency (SpF; s(-1)·100µm(-1): 5.8±0.3, P<0.01) was much more increased after the addition of isoproterenol than in WT cardiomyocytes (SpF: 3.6±0.2). The increase in SpF seen in KI cardiomyocytes was attenuated by 1.0µmol/L dantrolene (SpF: 3.6±0.5, P<0.01). CONCLUSIONS Dantrolene prevents CPVT, presumably by inhibiting Ca(2+) leak through the RyR2.
Collapse
Affiliation(s)
- Shigeki Kobayashi
- Department of Medicine and Clinical Science, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|