1
|
Calcium as a Key Player in Arrhythmogenic Cardiomyopathy: Adhesion Disorder or Intracellular Alteration? Int J Mol Sci 2019; 20:ijms20163986. [PMID: 31426283 PMCID: PMC6721231 DOI: 10.3390/ijms20163986] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 08/08/2019] [Accepted: 08/14/2019] [Indexed: 12/20/2022] Open
Abstract
Arrhythmogenic cardiomyopathy (ACM) is an inherited heart disease characterized by sudden death in young people and featured by fibro-adipose myocardium replacement, malignant arrhythmias, and heart failure. To date, no etiological therapies are available. Mutations in desmosomal genes cause abnormal mechanical coupling, trigger pro-apoptotic signaling pathways, and induce fibro-adipose replacement. Here, we discuss the hypothesis that the ACM causative mechanism involves a defect in the expression and/or activity of the cardiac Ca2+ handling machinery, focusing on the available data supporting this hypothesis. The Ca2+ toolkit is heavily remodeled in cardiomyocytes derived from a mouse model of ACM defective of the desmosomal protein plakophilin-2. Furthermore, ACM-related mutations were found in genes encoding for proteins involved in excitation‒contraction coupling, e.g., type 2 ryanodine receptor and phospholamban. As a consequence, the sarcoplasmic reticulum becomes more eager to release Ca2+, thereby inducing delayed afterdepolarizations and impairing cardiac contractility. These data are supported by preliminary observations from patient induced pluripotent stem-cell-derived cardiomyocytes. Assessing the involvement of Ca2+ signaling in the pathogenesis of ACM could be beneficial in the treatment of this life-threatening disease.
Collapse
|
2
|
Whole exome sequencing identified a pathogenic mutation in RYR2 in a Chinese family with unexplained sudden death. J Electrocardiol 2017; 51:309-315. [PMID: 29132927 DOI: 10.1016/j.jelectrocard.2017.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Indexed: 12/27/2022]
Abstract
OBJECTIVE This study aimed to identify the pathogenic mutation in a Chinese family with unexplained sudden death (USD) or occasional syncope. MATERIALS AND METHODS Whole exome sequencing and target capture sequencing were respectively conducted for two related patients. The genetic data was screened using the 1000 genomes project and SNP database (PubMed), and the identified mutations were assessed for predicted pathogenicity using the SIFT and Polyphen-2 algorithms. RESULTS We identified a heterozygous mutation in the RYR2 gene at c.490C>T (p.P164S), highly conserved across all species, in three family members of USD, syncope and malignant ventricular tachycardias induced by treadmill exercise test, while another heterozygous de novo mutation in SCN5A at c.5576G>A p.R1859H was detected in one family member. Both variants were verified by Sanger sequencing. Importantly, RYR2 p.P164S is associated with the risk of sudden cardiac death, such as in catecholaminergic polymorphic ventricular tachycardia. CONCLUSIONS A pathogenic mutation in RYR2 (p.P164S) is the likely cause of USD in a Chinese family associated with malignant ventricular arrhythmias. Whole exome and target capture sequencing can be useful for discovering the genetic causes of USD.
Collapse
|
3
|
Uehara A, Murayama T, Yasukochi M, Fill M, Horie M, Okamoto T, Matsuura Y, Uehara K, Fujimoto T, Sakurai T, Kurebayashi N. Extensive Ca2+ leak through K4750Q cardiac ryanodine receptors caused by cytosolic and luminal Ca2+ hypersensitivity. J Gen Physiol 2017; 149:199-218. [PMID: 28082361 PMCID: PMC5299618 DOI: 10.1085/jgp.201611624] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 10/19/2016] [Accepted: 12/07/2016] [Indexed: 12/20/2022] Open
Abstract
The K4750Q mutation in ryanodine receptor 2 causes severe catecholaminergic polymorphic ventricular tachycardia. Uehara et al. reveal extensive Ca2+ leak through this mutant receptor and show it is caused by altered gating kinetics, increased Ca2+ sensitivity, and the absence of Ca2+-dependent inactivation. Various ryanodine receptor 2 (RyR2) point mutations cause catecholamine-induced polymorphic ventricular tachycardia (CPVT), a life-threatening arrhythmia evoked by diastolic intracellular Ca2+ release dysfunction. These mutations occur in essential regions of RyR2 that regulate Ca2+ release. The molecular dysfunction caused by CPVT-associated RyR2 mutations as well as the functional consequences remain unresolved. Here, we study the most severe CPVT-associated RyR2 mutation (K4750Q) known to date. We define the molecular and cellular dysfunction generated by this mutation and detail how it alters RyR2 function, using Ca2+ imaging, ryanodine binding, and single-channel recordings. HEK293 cells and cardiac HL-1 cells expressing RyR2-K4750Q show greatly enhanced spontaneous Ca2+ oscillations. An endoplasmic reticulum–targeted Ca2+ sensor, R-CEPIA1er, revealed that RyR2-K4750Q mediates excessive diastolic Ca2+ leak, which dramatically reduces luminal [Ca2+]. We further show that the K4750Q mutation causes three RyR2 defects: hypersensitization to activation by cytosolic Ca2+, loss of cytosolic Ca2+/Mg2+-mediated inactivation, and hypersensitization to luminal Ca2+ activation. These defects combine to kinetically stabilize RyR2-K4750Q openings, thus explaining the extensive diastolic Ca2+ leak from the sarcoplasmic reticulum, frequent Ca2+ waves, and severe CPVT phenotype. As the multiple concurrent defects are induced by a single point mutation, the K4750 residue likely resides at a critical structural point at which cytosolic and luminal RyR2 control input converge.
Collapse
Affiliation(s)
- Akira Uehara
- Department of Physiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan
| | - Takashi Murayama
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - Midori Yasukochi
- Laboratory of Human Biology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan
| | - Michael Fill
- Department of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, IL 60612
| | - Minoru Horie
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Shiga 520-2192, Japan
| | - Toru Okamoto
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Yoshiharu Matsuura
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Kiyoko Uehara
- Department of Cell Biology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan
| | - Takahiro Fujimoto
- Department of Pathology and Applied Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Takashi Sakurai
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - Nagomi Kurebayashi
- Department of Pharmacology, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| |
Collapse
|
4
|
Prevalence and significance of rare RYR2 variants in arrhythmogenic right ventricular cardiomyopathy/dysplasia: Results of a systematic screening. Heart Rhythm 2014; 11:1999-2009. [DOI: 10.1016/j.hrthm.2014.07.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Indexed: 02/06/2023]
|
5
|
George CH, Parthimos D, Silvester NC. A network-oriented perspective on cardiac calcium signaling. Am J Physiol Cell Physiol 2012; 303:C897-910. [PMID: 22843795 DOI: 10.1152/ajpcell.00388.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The normal contractile, electrical, and energetic function of the heart depends on the synchronization of biological oscillators and signal integrators that make up cellular signaling networks. In this review we interpret experimental data from molecular, cellular, and transgenic models of cardiac signaling behavior in the context of established concepts in cell network architecture and organization. Focusing on the cellular Ca(2+) handling machinery, we describe how the plasticity and adaptability of normal Ca(2+) signaling is dependent on dynamic network configurations that operate across a wide range of functional states. We consider how (mal)adaptive changes in signaling pathways restrict the dynamic range of the network such that it cannot respond appropriately to physiologic stimuli or perturbation. Based on these concepts, a model is proposed in which pathologic abnormalities in cardiac rhythm and contractility (e.g., arrhythmias and heart failure) arise as a consequence of progressive desynchronization and reduction in the dynamic range of the Ca(2+) signaling network. We discuss how a systems-level understanding of the network organization, cellular noise, and chaotic behavior may inform the design of new therapeutic modalities that prevent or reverse the disease-linked unraveling of the Ca(2+) signaling network.
Collapse
Affiliation(s)
- Christopher H George
- Wales Heart Research Institute and Institute of Molecular and Experimental Medicine, School of Medicine, Cardiff Univ., Heath Park, Cardiff, Wales, UK CF14 4XN.
| | | | | |
Collapse
|
6
|
Mukherjee S, Thomas NL, Williams AJ. A mechanistic description of gating of the human cardiac ryanodine receptor in a regulated minimal environment. ACTA ACUST UNITED AC 2012; 140:139-58. [PMID: 22802361 PMCID: PMC3409104 DOI: 10.1085/jgp.201110706] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cardiac muscle contraction, triggered by the action potential, is mediated by the release of Ca2+ from the sarcoplasmic reticulum through ryanodine receptor (RyR)2 channels. In situ, RyR2 gating is modulated by numerous physiological and pharmacological agents, and altered RyR2 function underlies the occurrence of arrhythmias in both inherited and acquired diseases. To understand fully the mechanisms underpinning the regulation of RyR2 in the normal heart and how these systems are altered in pathological conditions, we must first gain a detailed knowledge of the fundamental processes of RyR2 gating. In this investigation, we provide key novel mechanistic insights into the physical reality of RyR2 gating revealed by new experimental and analytical approaches. We have examined in detail the single-channel gating kinetics of the purified human RyR2 when activated by cytosolic Ca2+ in a stringently regulated environment where the modulatory influence of factors external to the channel were minimized. The resulting gating schemes are based on an accurate description of single-channel kinetics using hidden Markov model analysis and reveal several novel aspects of RyR2 gating behavior: (a) constitutive gating is observed as unliganded opening events; (b) binding of Ca2+ to the channel stabilizes it in different open states; (c) RyR2 exists in two preopening closed conformations in equilibrium, one of which binds Ca2+ more readily than the other; (d) the gating of RyR2 when bound to Ca2+ can be described by a kinetic scheme incorporating bursts; and (e) analysis of flicker closing events within bursts reveals gating activity that is not influenced by ligand binding. The gating schemes generated in this investigation provide a framework for future studies in which the mechanisms of action of key physiological regulatory factors, disease-linked mutations, and potential therapeutic compounds can be described precisely.
Collapse
Affiliation(s)
- Saptarshi Mukherjee
- Institute of Molecular and Experimental Medicine, Wales Heart Research Institute, Cardiff University School of Medicine, Cardiff CF14 4XN, Wales, UK
| | | | | |
Collapse
|
7
|
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
|
8
|
Song DW, Lee JG, Youn HS, Eom SH, Kim DH. Ryanodine receptor assembly: A novel systems biology approach to 3D mapping. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2011; 105:145-61. [DOI: 10.1016/j.pbiomolbio.2010.09.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Revised: 09/14/2010] [Accepted: 09/28/2010] [Indexed: 10/19/2022]
|
9
|
Dhalla NS, Adameova A, Kaur M. Role of catecholamine oxidation in sudden cardiac death. Fundam Clin Pharmacol 2010; 24:539-46. [DOI: 10.1111/j.1472-8206.2010.00836.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
10
|
Lobo PA, Van Petegem F. Crystal structures of the N-terminal domains of cardiac and skeletal muscle ryanodine receptors: insights into disease mutations. Structure 2010; 17:1505-14. [PMID: 19913485 DOI: 10.1016/j.str.2009.08.016] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 08/12/2009] [Accepted: 08/22/2009] [Indexed: 11/17/2022]
Abstract
Ryanodine receptors (RyRs) are channels governing the release of Ca(2+) from the sarcoplasmic or endoplasmic reticulum. They are required for the contraction of both skeletal (RyR1) and cardiac (RyR2) muscles. Mutations in both RyR1 and RyR2 have been associated with severe genetic disorders, but high-resolution data describing the disease variants in detail have been lacking. Here we present the crystal structures of the N-terminal domains of both RyR2 (1-217) and RyR1 (9-205) at 2.55 A and 2.9 A, respectively. The domains map in a hot spot region for disease mutations. Both structures consist of a core beta trefoil domain flanked by an alpha helix. Crystal structures of two RyR2 disease mutants, A77V (2.2 A) and V186M (1.7 A), show that the mutations cause distinct local changes in the surface of the protein. A RyR2 deletion mutant causes significant changes in the thermal stability. The disease positions highlight two putative binding interfaces required for normal RyR function.
Collapse
Affiliation(s)
- Paolo Antonio Lobo
- University of British Columbia, Department of Biochemistry and Molecular Biology, Vancouver, BC V6T 1Z3 Canada
| | | |
Collapse
|
11
|
Marjamaa A, Laitinen-Forsblom P, Lahtinen AM, Viitasalo M, Toivonen L, Kontula K, Swan H. Search for cardiac calcium cycling gene mutations in familial ventricular arrhythmias resembling catecholaminergic polymorphic ventricular tachycardia. BMC MEDICAL GENETICS 2009; 10:12. [PMID: 19216760 PMCID: PMC2667497 DOI: 10.1186/1471-2350-10-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 02/12/2009] [Indexed: 11/18/2022]
Abstract
Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a severe inherited cardiac disorder caused by mutations predominantly in the ryanodine receptor (RyR2) gene. We sought to identify mutations in genes affecting cardiac calcium cycling in patients with CPVT and in less typical familial exercise-related ventricular arrhythmias. Methods and Results We recruited 33 consecutive patients with frequent ventricular premature complexes (VPCs) without structural heart disease and often history of syncope or sudden death in family. Sixteen of the patients featured a phenotype typical of CPVT. In 17 patients, VPCs emerged also at rest. Exercise stress test and echocardiography were performed to each patient and 232 family members. Familial background was evident in 42% of cases (n = 14). We sequenced all the coding exons of the RyR2, FKBP1B, ATP2A2 and SLC8A1 genes from the index patients. Single channel recordings of a mutant RyR2 were performed in planar lipid bilayers. Two novel RyR2 missense mutations (R1051P and S616L) and two RyR2 exon 3 deletions were identified, explaining 25% of the CPVT phenotypes. A rare variant (N3308S) with open probabilities similar to the wild type channels in vitro, was evident in a patient with resting VPCs. No disease-causing variants were detectable in the FKBP1B, ATP2A2 or SLC8A1 genes. Conclusion We report two novel CPVT-causing RyR2 mutations and a novel RyR2 variant of uncertain clinical significance in a patient with abundant resting VPCs. Our data also strengthen the previous assumption that exon 3 deletions of RyR2 should screened for in CPVT and related phenotypes.
Collapse
Affiliation(s)
- Annukka Marjamaa
- Department of Cardiology, University of Helsinki, Helsinki, Finland.
| | | | | | | | | | | | | |
Collapse
|
12
|
Yin CC, D’Cruz LG, Lai FA. Ryanodine receptor arrays: not just a pretty pattern? Trends Cell Biol 2008; 18:149-56. [DOI: 10.1016/j.tcb.2008.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2007] [Revised: 02/03/2008] [Accepted: 02/05/2008] [Indexed: 11/28/2022]
|