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Walweel K, Beard N, van Helden DF, Laver DR. Dantrolene inhibition of ryanodine channels (RyR2) in artificial lipid bilayers depends on FKBP12.6. J Gen Physiol 2023; 155:e202213277. [PMID: 37279522 PMCID: PMC10244881 DOI: 10.1085/jgp.202213277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 03/18/2023] [Accepted: 05/22/2023] [Indexed: 06/08/2023] Open
Abstract
Dantrolene is a neutral hydantoin that is clinically used as a skeletal muscle relaxant to prevent overactivation of the skeletal muscle calcium release channel (RyR1) in response to volatile anesthetics. Dantrolene has aroused considerable recent interest as a lead compound for stabilizing calcium release due to overactive cardiac calcium release channels (RyR2) in heart failure. Previously, we found that dantrolene produces up to a 45% inhibition RyR2 with an IC50 of 160 nM, and that this inhibition requires the physiological association between RyR2 and CaM. In this study, we tested the hypothesis that dantrolene inhibition of RyR2 in the presence of CaM is modulated by RyR2 phosphorylation at S2808 and S2814. Phosphorylation was altered by incubations with either exogenous phosphatase (PP1) or kinases; PKA to phosphorylate S2808 or endogenous CaMKII to phosphorylate S2814. We found that PKA caused selective dissociation of FKBP12.6 from the RyR2 complex and a loss of dantrolene inhibition. Rapamycin-induced FKBP12.6 dissociation from RyR2 also resulted in the loss of dantrolene inhibition. Subsequent incubations of RyR2 with exogenous FKBP12.6 reinstated dantrolene inhibition. These findings indicate that the inhibitory action of dantrolene on RyR2 depends on RyR2 association with FKBP12.6 in addition to CaM as previously found.
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Affiliation(s)
- Kafa Walweel
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia
| | - Nicole Beard
- Faculty of Science and Technology, University of Canberra, Bruce, Australia
| | - Dirk F. van Helden
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia
| | - Derek R. Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, Australia
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Engel MA, Wörmann YR, Kaestner H, Schüler C. An Optogenetic Arrhythmia Model—Insertion of Several Catecholaminergic Polymorphic Ventricular Tachycardia Mutations Into Caenorhabditis elegans UNC-68 Disturbs Calstabin-Mediated Stabilization of the Ryanodine Receptor Homolog. Front Physiol 2022; 13:691829. [PMID: 35399287 PMCID: PMC8990320 DOI: 10.3389/fphys.2022.691829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 02/15/2022] [Indexed: 11/14/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited disturbance of the heart rhythm (arrhythmia) that is induced by stress or that occurs during exercise. Most mutations that have been linked to CPVT are found in two genes, i.e., ryanodine receptor 2 (RyR2) and calsequestrin 2 (CASQ2), two proteins fundamentally involved in the regulation of intracellular Ca2+ in cardiac myocytes. We inserted six CPVT-causing mutations via clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 into unc-68 and csq-1, the Caenorhabditis elegans homologs of RyR and CASQ, respectively. We characterized those mutations via video-microscopy, electrophysiology, and calcium imaging in our previously established optogenetic arrhythmia model. In this study, we additionally enabled high(er) throughput recordings of intact animals by combining optogenetic stimulation with a microfluidic chip system. Whereas only minor/no pump deficiency of the pharynx was observed at baseline, three mutations of UNC-68 (S2378L, P2460S, Q4623R; RyR2-S2246L, -P2328S, -Q4201R) reduced the ability of the organ to follow 4 Hz optogenetic stimulation. One mutation (Q4623R) was accompanied by a strong reduction of maximal pump rate. In addition, S2378L and Q4623R evoked an altered calcium handling during optogenetic stimulation. The 1,4-benzothiazepine S107, which is suggested to stabilize RyR2 channels by enhancing the binding of calstabin2, reversed the reduction of pumping ability in a mutation-specific fashion. However, this depends on the presence of FKB-2, a C. elegans calstabin2 homolog, indicating the involvement of calstabin2 in the disease-causing mechanisms of the respective mutations. In conclusion, we showed for three CPVT-like mutations in C. elegans RyR a reduced pumping ability upon light stimulation, i.e., an arrhythmia-like phenotype, that can be reversed in two cases by the benzothiazepine S107 and that depends on stabilization via FKB-2. The genetically amenable nematode in combination with optogenetics and high(er) throughput recordings is a promising straightforward system for the investigation of RyR mutations and the selection of mutation-specific drugs.
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Affiliation(s)
- Marcial Alexander Engel
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Yves René Wörmann
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Hanna Kaestner
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
| | - Christina Schüler
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany
- *Correspondence: Christina Schüler,
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Shimamoto K, Ohno S, Kato K, Takayama K, Sonoda K, Fukuyama M, Makiyama T, Okamura S, Asakura K, Imanishi N, Kato Y, Sakaguchi H, Kamakura T, Wada M, Yamagata K, Ishibashi K, Inoue Y, Miyamoto K, Nagase S, Kusano K, Horie M, Aiba T. Impact of cascade screening for catecholaminergic polymorphic ventricular tachycardia type 1. Heart 2022; 108:840-847. [PMID: 35135837 PMCID: PMC9120385 DOI: 10.1136/heartjnl-2021-320220] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 12/30/2021] [Indexed: 11/06/2022] Open
Abstract
Objective Human cardiac ryanodine receptor 2 (RYR2) shows autosomal-dominant inheritance in catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1); however, de novo variants have been observed in sporadic cases. Here, we investigated CPVT1-related RYR2 variant inheritance and its clinical significance between familial and de novo cases. Methods We enrolled 82 independent CPVT1 probands (median age: 10.0 (7.0–13.0) years; 45 male) carrying the RYR2 variants and whose biological origin could be confirmed by parental genetic analysis: assured familial inheritance (familial group: n=24) and de novo variants (de novo group: n=58). We examined the clinical characteristics of the probands and their family members carrying the RYR2 variants. Results In the de novo group, the RYR2 variants were more likely located in the C-terminus domain and less likely in the N-terminus domain than those in the familial group. The cumulative incidence of the first cardiac events (syncope and cardiac arrest (CA) or CA only) of the probands at the age of 5 and 10 years was higher in the de novo group than in the familial group. Nearly half of the probands in both groups experienced CA events before diagnosis. Only 37.5% of their genotype-positive parents had symptoms; however, at least 66.7% of the genotype-positive siblings were symptomatic. Conclusions CPVT1 probands harbouring de novo RYR2 variants showed an earlier onset of symptoms than those with assured familial inheritance. Cascade screening may enable early diagnosis, risk stratification and prophylactic therapeutic intervention to prevent sudden cardiac death of probands and potential genotype-positive family members.
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Affiliation(s)
- Keiko Shimamoto
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Seiko Ohno
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Koichi Kato
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Koichiro Takayama
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Keiko Sonoda
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Megumi Fukuyama
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Takeru Makiyama
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Satomi Okamura
- Department of Data Science, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Koko Asakura
- Department of Data Science, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Noriaki Imanishi
- Department of Genomic Care, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Yoshiaki Kato
- Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Heima Sakaguchi
- Department of Pediatric Cardiology, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Tsukasa Kamakura
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Mitsuru Wada
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Kenichiro Yamagata
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Kohei Ishibashi
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Yuko Inoue
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Koji Miyamoto
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Satoshi Nagase
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Kengo Kusano
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Minoru Horie
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Takeshi Aiba
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan .,Department of Clinical Laboratory and Genetics, National Cerebral and Cardiovascular Center, Suita, Japan
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Chen L, He Y, Wang X, Ge J, Li H. Ventricular voltage-gated ion channels: Detection, characteristics, mechanisms, and drug safety evaluation. Clin Transl Med 2021; 11:e530. [PMID: 34709746 PMCID: PMC8516344 DOI: 10.1002/ctm2.530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 02/06/2023] Open
Abstract
Cardiac voltage-gated ion channels (VGICs) play critical roles in mediating cardiac electrophysiological signals, such as action potentials, to maintain normal heart excitability and contraction. Inherited or acquired alterations in the structure, expression, or function of VGICs, as well as VGIC-related side effects of pharmaceutical drug delivery can result in abnormal cellular electrophysiological processes that induce life-threatening cardiac arrhythmias or even sudden cardiac death. Hence, to reduce possible heart-related risks, VGICs must be acknowledged as important targets in drug discovery and safety studies related to cardiac disease. In this review, we first summarize the development and application of electrophysiological techniques that are employed in cardiac VGIC studies alone or in combination with other techniques such as cryoelectron microscopy, optical imaging and optogenetics. Subsequently, we describe the characteristics, structure, mechanisms, and functions of various well-studied VGICs in ventricular myocytes and analyze their roles in and contributions to both physiological cardiac excitability and inherited cardiac diseases. Finally, we address the implications of the structure and function of ventricular VGICs for drug safety evaluation. In summary, multidisciplinary studies on VGICs help researchers discover potential targets of VGICs and novel VGICs in heart, enrich their knowledge of the properties and functions, determine the operation mechanisms of pathological VGICs, and introduce groundbreaking trends in drug therapy strategies, and drug safety evaluation.
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Affiliation(s)
- Lulan Chen
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Yue He
- Department of CardiologyShanghai Xuhui District Central Hospital & Zhongshan‐xuhui HospitalShanghaiChina
| | - Xiangdong Wang
- Institute of Clinical Science, Zhongshan HospitalFudan UniversityShanghaiChina
| | - Junbo Ge
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
| | - Hua Li
- Department of Cardiology, Shanghai Institute of Cardiovascular DiseasesShanghai Xuhui District Central Hospital & Zhongshan‐xuhui Hospital, Zhongshan Hospital, Fudan UniversityShanghaiChina
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Feng X, Yu T, Zhang Y, Li L, Qu M, Wang J, Dong F, Zhang L, Wang F, Zhang F, Zhou X, Xu Z, Man D. Prenatal High-Sucrose Diet Induced Vascular Dysfunction in Thoracic Artery of Fetal Offspring. Mol Nutr Food Res 2021; 65:e2100072. [PMID: 33938121 DOI: 10.1002/mnfr.202100072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 04/19/2021] [Indexed: 12/18/2022]
Abstract
SCOPE Maternal nutrition during pregnancy is related to intrauterine fetal development. The authors' previous work reports that prenatal high sucrose (HS) diet impaired micro-vascular functions in postnatal offspring. It is unclear whether/how prenatal HS causes vascular injury during fetal life. METHODS AND RESULTS Pregnant rats are fed with normal drinking water or 20% high-sucrose solution during the whole gestational period. Pregnant HS increases maternal weight before delivery. Fetal thoracic aorta is separated for experiments. Angiotensin II (AII)-stimulated vascular contraction of fetal thoracic arteries in HS group is greater, which mainly results from the enhanced AT1 receptor (AT1R) function and the downstream signaling. Nifedipine significantly increases vascular tension in HS group, indicating that the L-type calcium channels (LTCCs) function is strengthened. 2-Aminoethyl diphenylborinate (2-APB), inositol 1,4,5-trisphosphate receptors (IP3Rs) inhibitor, increases vascular tension induced by AII in HS group and ryanodine receptors-sensitive vascular tone shows no difference in the two groups, which suggested that the activity of IP3Rs-operated calcium channels is increased. CONCLUSION These findings suggest that prenatal HS induces vascular dysfunction of thoracic arteries in fetal offspring by enhancing AT1R, LTCCs function and IP3Rs-associated calcium channels, providing new information regarding the impact of prenatal HS on the functional development of fetal vascular systems.
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Affiliation(s)
- Xueqin Feng
- Department of Obstetrics, Affiliated Hospital of Jining Medical University, Guhuai Road 89, Jining, 272001, China
| | - Tiantian Yu
- Department of Clinical Medicine, Jining Medical University, Hehua Road 133, Jining, 272067, China
| | - Yumeng Zhang
- Institute for Fetology, First Hospital of Soochow University, Renmin Road 708, Jiangsu, 215006, China
| | - Lijuan Li
- Department of Obstetrics, Affiliated Hospital of Jining Medical University, Guhuai Road 89, Jining, 272001, China
| | - Miaomiao Qu
- Department of Obstetrics, Affiliated Hospital of Jining Medical University, Guhuai Road 89, Jining, 272001, China
| | - Jishui Wang
- Department of Obstetrics, Affiliated Hospital of Jining Medical University, Guhuai Road 89, Jining, 272001, China
| | - Fangxiang Dong
- Department of Obstetrics, Affiliated Hospital of Jining Medical University, Guhuai Road 89, Jining, 272001, China
| | - Lihua Zhang
- Department of Obstetrics, Affiliated Hospital of Jining Medical University, Guhuai Road 89, Jining, 272001, China
| | - Fengge Wang
- Department of Obstetrics, Affiliated Hospital of Jining Medical University, Guhuai Road 89, Jining, 272001, China
| | - Fanyong Zhang
- Department of Obstetrics, Affiliated Hospital of Jining Medical University, Guhuai Road 89, Jining, 272001, China
| | - Xiuwen Zhou
- Institute for Fetology, First Hospital of Soochow University, Renmin Road 708, Jiangsu, 215006, China
| | - Zhice Xu
- Institute for Fetology, First Hospital of Soochow University, Renmin Road 708, Jiangsu, 215006, China
- Institute for Fetology, Maternal and Child Health Care Hospital of Wuxi, Huaishu Road 48, Jiangsu, 214002, China
| | - Dongmei Man
- Department of Obstetrics, Affiliated Hospital of Jining Medical University, Guhuai Road 89, Jining, 272001, China
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Wleklinski MJ, Kannankeril PJ, Knollmann BC. Molecular and tissue mechanisms of catecholaminergic polymorphic ventricular tachycardia. J Physiol 2020; 598:2817-2834. [PMID: 32115705 PMCID: PMC7699301 DOI: 10.1113/jp276757] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/03/2020] [Indexed: 12/21/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a stress-induced cardiac channelopathy that has a high mortality in untreated patients. Our understanding has grown tremendously since CPVT was first described as a clinical syndrome in 1995. It is now established that the deadly arrhythmias are caused by unregulated 'pathological' calcium release from the sarcoplasmic reticulum (SR), the major calcium storage organelle in striated muscle. Important questions remain regarding the molecular mechanisms that are responsible for the pathological calcium release, regarding the tissue origin of the arrhythmic beats that initiate ventricular tachycardia, and regarding optimal therapeutic approaches. At present, mutations in six genes involved in SR calcium release have been identified as the genetic cause of CPVT: RYR2 (encoding ryanodine receptor calcium release channel), CASQ2 (encoding cardiac calsequestrin), TRDN (encoding triadin), CALM1, CALM2 and CALM3 (encoding identical calmodulin protein). Here, we review each CPVT subtype and how CPVT mutations alter protein function, RyR2 calcium release channel regulation, and cellular calcium handling. We then discuss research and hypotheses surrounding the tissue mechanisms underlying CPVT, such as the pathophysiological role of sinus node dysfunction in CPVT, and whether the arrhythmogenic beats originate from the conduction system or the ventricular working myocardium. Finally, we review the treatments that are available for patients with CPVT, their efficacy, and how therapy could be improved in the future.
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Affiliation(s)
- Matthew J Wleklinski
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Prince J Kannankeril
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Bjӧrn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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7
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Ashna A, van Helden DF, Dos Remedios C, Molenaar P, Laver DR. Phenytoin Reduces Activity of Cardiac Ryanodine Receptor 2; A Potential Mechanism for Its Cardioprotective Action. Mol Pharmacol 2020; 97:250-258. [PMID: 32015008 DOI: 10.1124/mol.119.117721] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
Phenytoin is a hydantoin derivative that is used clinically for the treatment of epilepsy and has been reported to have antiarrhythmic actions on the heart. In a failing heart, the elevated diastolic Ca2+ leak from the sarcoplasmic reticulum can be normalized by the cardiac ryanodine receptor 2 (RyR2) inhibitor, dantrolene, without inhibiting Ca2+ release during systole or affecting Ca2+ release in normal healthy hearts. Unfortunately, dantrolene is hepatotoxic and unsuitable for chronic long-term administration. Because phenytoin and dantrolene belong to the hydantoin class of compounds, we test the hypothesis that dantrolene and phenytoin have similar inhibitory effects on RyR2 using a single-channel recording of RyR2 activity in artificial lipid bilayers. Phenytoin produced a reversible inhibition of RyR2 channels from sheep and human failing hearts. It followed a hyperbolic dose response with maximal inhibition of ∼50%, Hill coefficient ∼1, and IC50 ranging from 10 to 20 µM. It caused inhibition at diastolic cytoplasmic [Ca2+] but not at Ca2+ levels in the dyadic cleft during systole. Notably, phenytoin inhibits RyR2 from failing human heart but not from healthy heart, indicating that phenytoin may selectively target defective RyR2 channels in humans. We conclude that phenytoin could effectively inhibit RyR2-mediated release of Ca2+ in a manner paralleling that of dantrolene. Moreover, the IC50 of phenytoin in RyR2 is at least threefold lower than for other ion channels and clinically used serum levels, pointing to phenytoin as a more human-safe alternative to dantrolene for therapies against heart failure and cardiac arrythmias. SIGNIFICANCE STATEMENT: We show that phenytoin, a Na channel blocker used clinically for treatment of epilepsy, is a diastolic inhibitor of cardiac calcium release channels [cardiac ryanodine receptor 2 (RyR2)] at doses threefold lower than its current therapeutic levels. Phenytoin inhibits RyR2 from failing human heart and not from healthy heart, indicating that phenytoin may selectively target defective RyR2 channels in humans and pointing to phenytoin as a more human-safe alternative to dantrolene for therapies against heart failure and cardiac arrhythmias.
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Affiliation(s)
- A Ashna
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
| | - D F van Helden
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
| | - C Dos Remedios
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
| | - P Molenaar
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
| | - D R Laver
- School of Biomedical Sciences and Pharmacy, University of Newcastle and Hunter Medical Research Institute, Callaghan, New South Wales, Australia (A.A., D.F.v.H., D.R.L.); Bosch Institute, Discipline of Anatomy, University of Sydney, Sydney, New South Wales, Australia (C.d.R.); School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia (P.M.); and Northside Clinical School of Medicine, University of Queensland, Cardio-vascular Molecular & Therapeutics Translational Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia (P.M.)
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8
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De Mandal S, Shakeel M, Prabhakaran VS, Karthi S, Xu X, Jin F. Alternative splicing and insect ryanodine receptor. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2019; 102:e21590. [PMID: 31218747 DOI: 10.1002/arch.21590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/20/2019] [Accepted: 05/22/2019] [Indexed: 06/09/2023]
Abstract
Phylogenetic tree of the ryanodine receptor (RyR) family based on maximum likelihood estimation.
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Affiliation(s)
- Surajit De Mandal
- Laboratory of Bio-Pesticide Creation and Application of Guangdong Province, College of Agriculture, Department of Entomology, South China Agricultural University, Guangzhou, People's Republic of China
| | - Muhammad Shakeel
- Laboratory of Bio-Pesticide Creation and Application of Guangdong Province, College of Agriculture, Department of Entomology, South China Agricultural University, Guangzhou, People's Republic of China
| | | | - Sengodan Karthi
- Department of Environmental Sciences, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, India
| | - Xiaoxia Xu
- Laboratory of Bio-Pesticide Creation and Application of Guangdong Province, College of Agriculture, Department of Entomology, South China Agricultural University, Guangzhou, People's Republic of China
| | - Fengliang Jin
- Laboratory of Bio-Pesticide Creation and Application of Guangdong Province, College of Agriculture, Department of Entomology, South China Agricultural University, Guangzhou, People's Republic of China
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9
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Raghuraman H, Chatterjee S, Das A. Site-Directed Fluorescence Approaches for Dynamic Structural Biology of Membrane Peptides and Proteins. Front Mol Biosci 2019; 6:96. [PMID: 31608290 PMCID: PMC6774292 DOI: 10.3389/fmolb.2019.00096] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/11/2019] [Indexed: 12/31/2022] Open
Abstract
Membrane proteins mediate a number of cellular functions and are associated with several diseases and also play a crucial role in pathogenicity. Due to their importance in cellular structure and function, they are important drug targets for ~60% of drugs available in the market. Despite the technological advancement and recent successful outcomes in determining the high-resolution structural snapshot of membrane proteins, the mechanistic details underlining the complex functionalities of membrane proteins is least understood. This is largely due to lack of structural dynamics information pertaining to different functional states of membrane proteins in a membrane environment. Fluorescence spectroscopy is a widely used technique in the analysis of functionally-relevant structure and dynamics of membrane protein. This review is focused on various site-directed fluorescence (SDFL) approaches and their applications to explore structural information, conformational changes, hydration dynamics, and lipid-protein interactions of important classes of membrane proteins that include the pore-forming peptides/proteins, ion channels/transporters and G-protein coupled receptors.
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Affiliation(s)
- H. Raghuraman
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute, Kolkata, India
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10
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Del Franco A, Gualandi F, Malagù M, Ferlini A, Xiao D, Ferrari R, Bertini M. A Clinical Case of Catecholaminergic Polymorphic Ventricular Tachycardia: The Clinical Suspicious and the Need of Genetics. Cardiology 2017; 138:69-72. [PMID: 28605744 DOI: 10.1159/000475461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 03/23/2017] [Indexed: 11/19/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a very rare genetic cardiac channelopathy, which has not been sufficiently studied yet. The first clinical manifestation has been described during the first decade of life, linked to strenuous exercise or acute emotion. The absence of structural heart disease and a family history of possible arrhythmogenic disorder generally guide the diagnosis towards a potential channelopathy. The opportunity to perform an extensive genetic analysis allows physicians to make the correct diagnosis and to optimize clinical management. The identification of more CPVT cases could affirm what we already know and primarily implement the current knowledge.
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Affiliation(s)
- Annamaria Del Franco
- Cardiovascular Istitute, Azienda Ospedaliera Universitaria di Ferrara, Universitaria di Ferrara, Ferrara, Italy
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11
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George CH, Edwards DH. Decoding Ca2+ Signals as a Non-electrophysiological Method for Assessing Drug Toxicity in Stem Cell-Derived Cardiomyocytes. METHODS IN PHARMACOLOGY AND TOXICOLOGY 2017. [DOI: 10.1007/978-1-4939-6661-5_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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12
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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.
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Gender Differences in the Inheritance Mode of RYR2 Mutations in Catecholaminergic Polymorphic Ventricular Tachycardia Patients. PLoS One 2015; 10:e0131517. [PMID: 26114861 PMCID: PMC4482545 DOI: 10.1371/journal.pone.0131517] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 06/03/2015] [Indexed: 11/19/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is one of the causes of sudden cardiac death in young people and results from RYR2 mutations in ~60% of CPVT patients. The inheritance of the RYR2 mutations follows an autosomal dominant trait, however, de novo mutations are often identified during familial analysis. In 36 symptomatic CPVT probands with RYR2 mutations, we genotyped their parents and confirmed the origin of the respective mutation. In 26 sets of proband and both parents (trio), we identified 17 de novo mutations (65.4%), seven from their mothers and only two mutations were inherited from their fathers. Among nine sets of proband and mother, five mutations were inherited from mothers. Four other mutations were of unknown origin. The inheritance of RYR2 mutations was significantly more frequent from mothers (n = 12, 34.3%) than fathers (n = 2, 5.7%) (P = 0.013). The mean ages of onset were not significantly different in probands between de novo mutations and those from mothers. Thus, half of the RYR2 mutations in our cohort were de novo, and most of the remaining mutations were inherited from mothers. These data would be useful for family analysis and risk stratification of the disease.
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14
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Ma L, Yang F, Zheng J. Application of fluorescence resonance energy transfer in protein studies. J Mol Struct 2014; 1077:87-100. [PMID: 25368432 DOI: 10.1016/j.molstruc.2013.12.071] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Since the physical process of fluorescence resonance energy transfer (FRET) was elucidated more than six decades ago, this peculiar fluorescence phenomenon has turned into a powerful tool for biomedical research due to its compatibility in scale with biological molecules as well as rapid developments in novel fluorophores and optical detection techniques. A wide variety of FRET approaches have been devised, each with its own advantages and drawbacks. Especially in the last decade or so, we are witnessing a flourish of FRET applications in biological investigations, many of which exemplify clever experimental design and rigorous analysis. Here we review the current stage of FRET methods development with the main focus on its applications in protein studies in biological systems, by summarizing the basic components of FRET techniques, most established quantification methods, as well as potential pitfalls, illustrated by example applications.
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Affiliation(s)
- Linlin Ma
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA 95616, USA ; Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Fan Yang
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA 95616, USA
| | - Jie Zheng
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA 95616, USA
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15
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Seidel M, Thomas NL, Williams AJ, Lai FA, Zissimopoulos S. Dantrolene rescues aberrant N-terminus intersubunit interactions in mutant pro-arrhythmic cardiac ryanodine receptors. Cardiovasc Res 2014; 105:118-28. [PMID: 25411383 DOI: 10.1093/cvr/cvu240] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS The ryanodine receptor (RyR2) is an intracellular Ca(2+) release channel essential for cardiac excitation-contraction coupling. Abnormal RyR2 channel function results in the generation of arrhythmias and sudden cardiac death. The present study was undertaken to investigate the mechanistic basis of RyR2 dysfunction in inherited arrhythmogenic cardiac disease. METHODS AND RESULTS We present several lines of complementary evidence, indicating that the arrhythmia-associated L433P mutation disrupts RyR2 N-terminus self-association. A combination of yeast two-hybrid, co-immunoprecipitation, and chemical cross-linking assays collectively demonstrate that a RyR2 N-terminal fragment carrying the L433P mutation displays substantially reduced self-interaction compared with wild type. Moreover, sucrose density gradient centrifugation reveals that the L433P mutation impairs tetramerization of the full-length channel. [(3)H]Ryanodine-binding assays demonstrate that disrupted N-terminal intersubunit interactions within RyR2(L433P) confer an altered sensitivity to Ca(2+) activation. Calcium imaging of RyR2(L433P)-expressing cells reveals substantially prolonged Ca(2+) transients and reduced Ca(2+) store content indicating defective channel closure. Importantly, dantrolene treatment reverses the L433P mutation-induced impairment and restores channel function. CONCLUSION The N-terminus domain constitutes an important structural determinant for the functional oligomerization of RyR2. Our findings are consistent with defective N-terminus self-association as a molecular mechanism underlying RyR2 channel deregulation in inherited arrhythmogenic cardiac disease. Significantly, the therapeutic action of dantrolene may occur via the restoration of normal RyR2 N-terminal intersubunit interactions.
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Affiliation(s)
- Monika Seidel
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - N Lowri Thomas
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - Alan J Williams
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - F Anthony Lai
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
| | - Spyros Zissimopoulos
- Wales Heart Research Institute, Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Cardiff CF14 4XN, UK
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16
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Siragam V, Cui X, Masse S, Ackerley C, Aafaqi S, Strandberg L, Tropak M, Fridman MD, Nanthakumar K, Liu J, Sun Y, Su B, Wang C, Liu X, Yan Y, Mendlowitz A, Hamilton RM. TMEM43 mutation p.S358L alters intercalated disc protein expression and reduces conduction velocity in arrhythmogenic right ventricular cardiomyopathy. PLoS One 2014; 9:e109128. [PMID: 25343256 PMCID: PMC4208740 DOI: 10.1371/journal.pone.0109128] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 09/08/2014] [Indexed: 01/04/2023] Open
Abstract
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a myocardial disease characterized by fibro-fatty replacement of myocardium in the right ventricular free wall and frequently results in life-threatening ventricular arrhythmias and sudden cardiac death. A heterozygous missense mutation in the transmembrane protein 43 (TMEM43) gene, p.S358L, has been genetically identified to cause autosomal dominant ARVC type 5 in a founder population from the island of Newfoundland, Canada. Little is known about the function of the TMEM43 protein or how it leads to the pathogenesis of ARVC. We sought to determine the distribution of TMEM43 and the effect of the p.S358L mutation on the expression and distribution of various intercalated (IC) disc proteins as well as functional effects on IC disc gap junction dye transfer and conduction velocity in cell culture. Through Western blot analysis, transmission electron microscopy (TEM), immunofluorescence (IF), and electrophysiological analysis, our results showed that the stable expression of p.S358L mutation in the HL-1 cardiac cell line resulted in decreased Zonula Occludens (ZO-1) expression and the loss of ZO-1 localization to cell-cell junctions. Junctional Plakoglobin (JUP) and α-catenin proteins were redistributed to the cytoplasm with decreased localization to cell-cell junctions. Connexin-43 (Cx43) phosphorylation was altered, and there was reduced gap junction dye transfer and conduction velocity in mutant TMEM43-transfected cells. These observations suggest that expression of the p.S358L mutant of TMEM43 found in ARVC type 5 may affect localization of proteins involved in conduction, alter gap junction function and reduce conduction velocity in cardiac tissue.
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Affiliation(s)
- Vinayakumar Siragam
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Xuezhi Cui
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Stephane Masse
- Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Cameron Ackerley
- Division of Pathology, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Shabana Aafaqi
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Linn Strandberg
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Michael Tropak
- Genetics and Genome Biology, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Michael D. Fridman
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | | | - Jun Liu
- Advanced Micro and Nanosystems Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Yu Sun
- Advanced Micro and Nanosystems Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Bin Su
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Caroline Wang
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Xiaoru Liu
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Yuqing Yan
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Ariel Mendlowitz
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
| | - Robert M. Hamilton
- Physiology and Experimental Medicine, The Hospital for Sick Children and Research Institute, Toronto, Ontario, Canada
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17
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Yuan GR, Shi WZ, Yang WJ, Jiang XZ, Dou W, Wang JJ. Molecular characteristics, mRNA expression, and alternative splicing of a ryanodine receptor gene in the oriental fruit fly, Bactrocera dorsalis (Hendel). PLoS One 2014; 9:e95199. [PMID: 24740254 PMCID: PMC3989282 DOI: 10.1371/journal.pone.0095199] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 03/24/2014] [Indexed: 01/13/2023] Open
Abstract
Ryanodine receptors (RyRs) are a distinct class of ligand-gated channels controlling the release of calcium from intracellular stores. The emergence of diamide insecticides, which selectively target insect RyRs, has promoted the study of insect RyRs. In the present study, the full-length RyR cDNA (BdRyR) was cloned and characterized from the oriental fruit fly, Bactrocera dorsalis (Hendel), a serious pest of fruits and vegetables throughout East Asia and the Pacific Rim. The cDNA of BdRyR contains a 15,420-bp open reading frame encoding 5,140 amino acids with a predicted molecular weight of 582.4 kDa and an isoelectric point of 5.38. BdRyR shows a high level of amino acid sequence identity (78 to 97%) to other insect RyR isoforms. All common structural features of the RyRs are present in the BdRyR, including a well-conserved C-terminal domain containing consensus calcium-binding EF-hands and six transmembrane domains, and a large N-terminal domain. Quantitative real-time PCR analyses revealed that BdRyR was expressed at the lowest and highest levels in egg and adult, respectively, and that the BdRyR expression levels in the third instar larva, pupa and adult were 166.99-, 157.56- and 808.56-fold higher, respectively, than that in the egg. Among different adult body parts, the highest expression level was observed in the thorax compared with the head and abdomen. In addition, four alternative splice sites were identified in the BdRyR gene, with the first, ASI, being located in the central part of the predicted second spore lysis A/RyR domain. Diagnostic PCR analyses revealed that alternative splice variants were generated not only in a tissue-specific manner but also in a developmentally regulated manner. These results lay the foundation for further understanding the structural and functional properties of BdRyR, and the molecular mechanisms for target site resistance in B. dorsalis.
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Affiliation(s)
- Guo-Rui Yuan
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Wen-Zhi Shi
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Wen-Jia Yang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Xuan-Zhao Jiang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Wei Dou
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Jin-Jun Wang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
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18
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Ohno S, Omura M, Kawamura M, Kimura H, Itoh H, Makiyama T, Ushinohama H, Makita N, Horie M. Exon 3 deletion of RYR2 encoding cardiac ryanodine receptor is associated with left ventricular non-compaction. Europace 2014; 16:1646-54. [PMID: 24394973 DOI: 10.1093/europace/eut382] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
AIMS Ryanodine receptor gene (RYR2) mutations are well known to cause catecholaminergic polymorphic ventricular tachycardia (CPVT). Recently, RYR2 exon 3 deletion has been identified in patients with dilated cardiomyopathy (DCM) and/or CPVT. This study aimed to screen for the RYR2 exon 3 deletion in CPVT probands, characterize its clinical pathology, and confirm the genomic rearrangement. METHODS AND RESULTS Our cohort consisted of 24 CPVT probands. Polymerase chain reaction (PCR)-based conventional genetic analysis did not identify any mutations in coding exons of RYR2 in these probands. They were screened using multiplex ligation-dependent probe amplification (MLPA). In probands identified with RYR2 exon 3 deletion, the precise location of the deletion was identified by quantitative PCR and direct sequencing methods. We identified two CPVT probands from unrelated families who harboured a large deletion including exon 3. The probands were 9- and 17-year-old girls. Both probands had a history of syncope related to emotional stress or exercise, exhibited bradycardia, and were diagnosed with left ventricular non-compaction (LVNC). We examined 10 family members and identified six more RYR2 exon 3 deletion carriers. In total, there were eight carriers, of which seven were diagnosed with LVNC (87.5%). Two carriers under the age of 4 years remained asymptomatic, although they were diagnosed with LVNC. Using quantitative PCR and direct sequencing, we confirmed that the deletions were 1.1 and 37.7 kb in length. CONCLUSION RYR2 exon 3 deletion is frequently associated with LVNC. Therefore, detection of the deletion offers a new modality for predicting the prognosis of patients with LVNC with ventricular/atrial arrhythmias, particularly in children.
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Affiliation(s)
- Seiko Ohno
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga 520-2192, Japan
| | - Masato Omura
- Cardiovasacular Department, Saiseikai Shimonoseki General Hospital, Shimonoseki 759-6603, Japan
| | - Mihoko Kawamura
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga 520-2192, Japan
| | - Hiromi Kimura
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga 520-2192, Japan
| | - Hideki Itoh
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga 520-2192, Japan
| | - Takeru Makiyama
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Hiroya Ushinohama
- Cardiovascular Department, Fukuoka Children's Hospital and Medical Center for infectious disease, Fukuoka 810-0063, Japan
| | - Naomasa Makita
- Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Science, Nagasaki 852-8523, Japan
| | - Minoru Horie
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga 520-2192, Japan
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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.
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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
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20
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Loaiza R, Benkusky NA, Powers PP, Hacker T, Noujaim S, Ackerman MJ, Jalife J, Valdivia HH. Heterogeneity of ryanodine receptor dysfunction in a mouse model of catecholaminergic polymorphic ventricular tachycardia. Circ Res 2012; 112:298-308. [PMID: 23152493 DOI: 10.1161/circresaha.112.274803] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Most cardiac ryanodine receptor (RyR2) mutations associated with catecholaminergic polymorphic ventricular tachycardia (CPVT) are postulated to cause a distinctive form of Ca(2+) release dysfunction. Considering the spread distribution of CPVT mutations, we hypothesized that dysfunctional heterogeneity also was feasible. OBJECTIVE To determine the molecular and cellular mechanisms by which a novel RyR2-V2475F mutation associated with CPVT in humans triggers Ca(2+)-dependent arrhythmias in whole hearts and intact mice. METHODS AND RESULTS Recombinant channels harboring CPVT-linked RyR2 mutations were functionally characterized using tritiated ryanodine binding and single-channel recordings. Homologous recombination was used to generate a knock-in mouse bearing the RyR2-V2475F mutation. Ventricular myocytes from mice heterozygous for the mutation (RyR2-V2475F(+/-)) and their wild-type littermates were Ca(2+)-imaged by confocal microscopy under conditions that mimic stress. The propensity of wild-type and RyR2-V2475F(+/-) mice to have development of arrhythmias was tested at the whole heart level and in intact animals. Recombinant RyR2-V2475F channels displayed increased cytosolic Ca(2+) activation, abnormal protein kinase A phosphorylation, and increased activation by luminal Ca(2+). The RyR2-V2475F mutation appears embryonic-lethal in homozygous mice, but heterozygous mice have no alterations at baseline. Spontaneous Ca(2+) release events were more frequent and had shorter latency in isoproterenol-stimulated cardiomyocytes from RyR2-V2475F(+/-) hearts, but their threshold was unchanged with respect to wild-type. Adrenergically triggered tachyarrhythmias were more frequent in RyR2-V2475F(+/-) mice. CONCLUSIONS The mutation RyR2-V2475F is phenotypically strong among other CPVT mutations and produces heterogeneous mechanisms of RyR2 dysfunction. In living mice, this mutation appears too severe to be harbored in all RyR2 channels but remains undetected under basal conditions if expressed at relatively low levels. β-adrenergic stimulation breaks the delicate Ca(2+) equilibrium of RyR2-V2475F(+/-) hearts and triggers life-threatening arrhythmias.
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Affiliation(s)
- Randall Loaiza
- Center for Arrhythmia Research, Cardiovascular Division, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
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van der Werf C, Nederend I, Hofman N, van Geloven N, Ebink C, Frohn-Mulder IM, Alings AMW, Bosker HA, Bracke FA, van den Heuvel F, Waalewijn RA, Bikker H, van Tintelen JP, Bhuiyan ZA, van den Berg MP, Wilde AA. Familial Evaluation in Catecholaminergic Polymorphic Ventricular Tachycardia. Circ Arrhythm Electrophysiol 2012; 5:748-56. [DOI: 10.1161/circep.112.970517] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Christian van der Werf
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Ineke Nederend
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Nynke Hofman
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Nan van Geloven
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Corné Ebink
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Ingrid M.E. Frohn-Mulder
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - A. Marco W. Alings
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Hans A. Bosker
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Frank A. Bracke
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Freek van den Heuvel
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Reinier A. Waalewijn
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Hennie Bikker
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - J. Peter van Tintelen
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Zahurul A. Bhuiyan
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Maarten P. van den Berg
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
| | - Arthur A.M. Wilde
- From the Department of Cardiology, Heart Failure Research Center (C.v.d.W., I.N., A.A.M.W.), Department of Clinical Genetics (N.H., H.B., Z.A.B.), and Clinical Research Unit (N.v.G.), Academic Medical Center, Amsterdam, The Netherlands; Department of Cardiology, Maasstad Hospital, Rotterdam, The Netherlands (C.E.); Department of Pediatrics, Division of Pediatric Cardiology, Erasmus MC-Sophia, Rotterdam, The Netherlands (I.M.E.F-M.); Department of Cardiology, Amphia Hospital, Breda, The Netherlands
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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.
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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.
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23
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Chen B, Guo A, Gao Z, Wei S, Xie YP, Chen SRW, Anderson ME, Song LS. In situ confocal imaging in intact heart reveals stress-induced Ca(2+) release variability in a murine catecholaminergic polymorphic ventricular tachycardia model of type 2 ryanodine receptor(R4496C+/-) mutation. Circ Arrhythm Electrophysiol 2012; 5:841-9. [PMID: 22722659 DOI: 10.1161/circep.111.969733] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Catecholaminergic polymorphic ventricular tachycardia is directly linked to mutations in proteins (eg, type 2 ryanodine receptor [RyR2](R4496C)) responsible for intracellular Ca(2+) homeostasis in the heart. However, the mechanism of Ca(2+) release dysfunction underlying catecholaminergic polymorphic ventricular tachycardia has only been investigated in isolated cells but not in the in situ undisrupted myocardium. METHODS AND RESULTS We investigated in situ myocyte Ca(2+) dynamics in intact Langendorff-perfused hearts (ex vivo) from wild-type and RyR2(R4496C+/-) mice using laser scanning confocal microscopy. We found that myocytes from both wild-type and RyR2(R4496C+/-) hearts displayed uniform, synchronized Ca(2+) transients. Ca(2+) transients from beat to beat were comparable in amplitude with identical activation and decay kinetics in wild-type and RyR2(R4496C+/-) hearts, suggesting that excitation-contraction coupling between the sarcolemmal Ca(2+) channels and mutated RyR2(R4496C+/-) channels remains intact under baseline resting conditions. On adrenergic stimulation, RyR2(R4496C+/-) hearts exhibited a high degree of Ca(2+) release variability. The varied pattern of Ca(2+) release was absent in single isolated myocytes, independent of cell cycle length, synchronized among neighboring myocytes, and correlated with catecholaminergic polymorphic ventricular tachycardia. A similar pattern of action potential variability, which was synchronized among neighboring myocytes, was also revealed under adrenergic stress in intact hearts but not in isolated myocytes. CONCLUSIONS Our studies using an in situ confocal imaging approach suggest that mutated RyR2s are functionally normal at rest but display a high degree of Ca(2+) release variability on intense adrenergic stimulation. Ca(2+) release variability is a Ca(2+) release abnormality, resulting from electric defects rather than the failure of the Ca(2+) release response to action potentials in mutated ventricular myocytes. Our data provide important insights into Ca(2+) release and electric dysfunction in an established model of catecholaminergic polymorphic ventricular tachycardia.
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Affiliation(s)
- Biyi Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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24
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Popov S, Venetsanou K, Chedrese PJ, Pinto V, Takemori H, Franco-Cereceda A, Eriksson P, Mochizuki N, Soares-da-Silva P, Bertorello AM. Increases in intracellular sodium activate transcription and gene expression via the salt-inducible kinase 1 network in an atrial myocyte cell line. Am J Physiol Heart Circ Physiol 2012; 303:H57-65. [PMID: 22467310 DOI: 10.1152/ajpheart.00512.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cardiac hypertrophy (CH) generally occurs as the result of the sustained mechanical stress caused by elevated systemic arterial blood pressure (BP). However, in animal models, elevated salt intake is associated with CH even in the absence of significant increases in BP. We hypothesize that CH is not exclusively the consequence of mechanical stress but also of other factors associated with elevated BP such as abnormal cell sodium homeostasis. We examined the effect of small increases in intracellular sodium concentration ([Na(+)](i)) on transcription factors and genes associated with CH in a cardiac cell line. Increases in [Na(+)](i) led to a time-dependent increase in the expression levels of mRNA for natriuretic peptide and myosin heavy chain genes and also increased myocyte enhancer factor (MEF)2/nuclear factor of activated T cell (NFAT) transcriptional activity. Increases in [Na(+)](i) are associated with activation of salt-inducible kinase 1 (snflk-1, SIK1), a kinase known to be critical for cardiac development. Moreover, increases in [Na(+)](i) resulted in increased SIK1 expression. Sodium did not increase MEF2/NFAT activity or gene expression in cells expressing a SIK1 that lacked kinase activity. The mechanism by which SIK1 activated MEF2 involved phosphorylation of HDAC5. Increases in [Na(+)](i) activate SIK1 and MEF2 via a parallel increase in intracellular calcium through the reverse mode of Na(+)/Ca(2+)-exchanger and activation of CaMK1. These data obtained in a cardiac cell line suggest that increases in intracellular sodium could influence myocardial growth by controlling transcriptional activation and gene expression throughout the activation of the SIK1 network.
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Affiliation(s)
- Sergej Popov
- Membrane Signaling Networks, Atherosclerosis Research Unit, Department of Medicine, CMM, Karolinska Institutet, Karolinska University Hospital-Solna, Stockholm, Sweden
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25
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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]
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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]
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27
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Divergent effect of mammalian PLCζ in generating Ca²⁺ oscillations in somatic cells compared with eggs. Biochem J 2011; 438:545-53. [PMID: 21692749 PMCID: PMC3195308 DOI: 10.1042/bj20101581] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Sperm PLCζ (phospholipase Cζ) is a distinct phosphoinositide-specific PLC isoform that is proposed to be the physiological trigger of egg activation and embryo development at mammalian fertilization. Recombinant PLCζ has the ability to trigger Ca²⁺ oscillations when expressed in eggs, but it is not known how PLCζ activity is regulated in sperm or eggs. In the present study, we have transfected CHO (Chinese-hamster ovary) cells with PLCζ fused with either YFP (yellow fluorescent protein) or luciferase and found that PLCζ-transfected cells did not display cytoplasmic Ca²⁺ oscillations any differently from control cells. PLCζ expression was not associated with changes in CHO cell resting Ca²⁺ levels, nor with a significantly changed Ca²⁺ response to extracellular ATP compared with control cells transfected with either YFP alone, a catalytically inactive PLCζ or luciferase alone. Sperm extracts containing PLCζ also failed to cause Ca²⁺ oscillations in CHO cells. Despite these findings, PLCζ-transfected CHO cell extracts exhibited high recombinant protein expression and PLC activity. Furthermore, either PLCζ-transfected CHO cells or derived cell extracts could specifically cause cytoplasmic Ca²⁺ oscillations when microinjected into mouse eggs. These data suggest that PLCζ-mediated Ca²⁺ oscillations may require specific factors that are only present within the egg cytoplasm or be inhibited by factors present only in somatic cell lines.
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Schimpf R, Borggrefe M. From ECG to mutation: Programmed ventricular stimulation providing a link to genetics of cardiac channelopathies. Heart Rhythm 2011; 8:1553-4. [DOI: 10.1016/j.hrthm.2011.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Indexed: 11/16/2022]
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Suetomi T, Yano M, Uchinoumi H, Fukuda M, Hino A, Ono M, Xu X, Tateishi H, Okuda S, Doi M, Kobayashi S, Ikeda Y, Yamamoto T, Ikemoto N, Matsuzaki M. Mutation-linked defective interdomain interactions within ryanodine receptor cause aberrant Ca²⁺release leading to catecholaminergic polymorphic ventricular tachycardia. Circulation 2011; 124:682-94. [PMID: 21768539 DOI: 10.1161/circulationaha.111.023259] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The molecular mechanism by which catecholaminergic polymorphic ventricular tachycardia is induced by single amino acid mutations within the cardiac ryanodine receptor (RyR2) remains elusive. In the present study, we investigated mutation-induced conformational defects of RyR2 using a knockin mouse model expressing the human catecholaminergic polymorphic ventricular tachycardia-associated RyR2 mutant (S2246L; serine to leucine mutation at the residue 2246). METHODS AND RESULTS All knockin mice we examined produced ventricular tachycardia after exercise on a treadmill. cAMP-dependent increase in the frequency of Ca²⁺ sparks was more pronounced in saponin-permeabilized knockin cardiomyocytes than in wild-type cardiomyocytes. Site-directed fluorescent labeling and quartz microbalance assays of the specific binding of DP2246 (a peptide corresponding to the 2232 to 2266 region: the 2246 domain) showed that DP2246 binds with the K201-binding sequence of RyR2 (1741 to 2270). Introduction of S2246L mutation into the DP2246 increased the affinity of peptide binding. Fluorescence quench assays of interdomain interactions within RyR2 showed that tight interaction of the 2246 domain/K201-binding domain is coupled with domain unzipping of the N-terminal (1 to 600)/central (2000 to 2500) domain pair in an allosteric manner. Dantrolene corrected the mutation-caused domain unzipping of the domain switch and stopped the exercise-induced ventricular tachycardia. CONCLUSIONS The catecholaminergic polymorphic ventricular tachycardia-linked mutation of RyR2, S2246L, causes an abnormally tight local subdomain-subdomain interaction within the central domain involving the mutation site, which induces defective interaction between the N-terminal and central domains. This results in an erroneous activation of Ca²⁺ channel in a diastolic state reflecting on the increased Ca²⁺ spark frequency, which then leads to lethal arrhythmia.
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Affiliation(s)
- Takeshi Suetomi
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, 755-8505, Japan
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Postpacing abnormal repolarization in catecholaminergic polymorphic ventricular tachycardia associated with a mutation in the cardiac ryanodine receptor gene. Heart Rhythm 2011; 8:1546-52. [PMID: 21699856 DOI: 10.1016/j.hrthm.2011.05.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Accepted: 05/17/2011] [Indexed: 11/23/2022]
Abstract
BACKGROUND Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an arrhythmogenic disease for which electrophysiological studies (EPS) have shown to be of limited value. OBJECTIVE This study presents a CPVT family in which marked postpacing repolarization abnormalities during EPS were the only consistent phenotypic manifestation of ryanodine receptor (RyR2) mutation carriers. METHODS The study was prompted by the observation of transient marked QT prolongation preceding initiation of ventricular fibrillation during atrial fibrillation in a boy with a family history of sudden cardiac death (SCD). Family members underwent exercise and pharmacologic electrocardiographic testing with epinephrine, adenosine, and flecainide. Noninvasive clinical test results were normal in 10 patients evaluated, except for both epinephrine- and exercise-induced ventricular arrhythmias in 1. EPS included bursts of ventricular pacing and programmed ventricular extrastimulation reproducing short-long sequences. Genetic screening involved direct sequencing of genes involved in long QT syndrome as well as RyR2. RESULTS Six patients demonstrated a marked increase in QT interval only in the first beat after cessation of ventricular pacing and/or extrastimulation. All 6 patients were found to have a heterozygous missense mutation (M4109R) in RyR2. Two of them, presenting with aborted SCD, also had a second missense mutation (I406T- RyR2). Four family members without RyR2 mutations did not display prominent postpacing QT changes. CONCLUSION M4109R- RyR2 is associated with a high incidence of SCD. The contribution of I406T to the clinical phenotype is unclear. In contrast to exercise testing, marked postpacing repolarization changes in a single beat accurately predicted carriers of M4109R- RyR2 in this family.
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Wei L, Dirksen RT. Ryanodinopathies: RyR-Linked Muscle Diseases. CURRENT TOPICS IN MEMBRANES 2010; 66:139-67. [PMID: 22353479 DOI: 10.1016/s1063-5823(10)66007-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
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Betzenhauser MJ, Marks AR. Ryanodine receptor channelopathies. Pflugers Arch 2010; 460:467-80. [PMID: 20179962 PMCID: PMC2885589 DOI: 10.1007/s00424-010-0794-4] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 01/26/2010] [Accepted: 01/28/2010] [Indexed: 02/07/2023]
Abstract
Ryanodine receptors (RyR) are intracellular Ca2+-permeable channels that provide the sarcoplasmic reticulum Ca2+ release required for skeletal and cardiac muscle contractions. RyR1 underlies skeletal muscle contraction, and RyR2 fulfills this role in cardiac muscle. Over the past 20 years, numerous mutations in both RyR isoforms have been identified and linked to skeletal and cardiac diseases. Malignant hyperthermia, central core disease, and catecholaminergic polymorphic ventricular tachycardia have been genetically linked to mutations in either RyR1 or RyR2. Thus, RyR channelopathies are both of interest because they cause significant human diseases and provide model systems that can be studied to elucidate important structure-function relationships of these ion channels.
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Affiliation(s)
- Matthew J Betzenhauser
- Department of Physiology, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
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33
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Nynke Hofman, Laura T van Lochem, Arthur AM Wilde. Genetic basis of malignant channelopathies and ventricular fibrillation in the structurally normal heart. Future Cardiol 2010; 6:395-408. [DOI: 10.2217/fca.10.11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Sudden cardiac death occurs in a minority of patients in the absence of structural or functional abnormalities. In this category, pure electrical heart diseases are responsible for a large number of these unexpected deaths. These conditions include the long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, short QT syndrome (collectively referred to as channelopathies) and idiopathic ventricular fibrillation. This article reviews the current molecular understanding of the electrical diseases of the heart associated with sudden cardiac death, and provides a summary of the causal genes and a flowchart with an overview of the genotype–phenotype correlation of the most common arrhythmia syndromes.
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34
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Uchinoumi H, Yano M, Suetomi T, Ono M, Xu X, Tateishi H, Oda T, Okuda S, Doi M, Kobayashi S, Yamamoto T, Ikeda Y, Ohkusa T, Ikemoto N, Matsuzaki M. Catecholaminergic polymorphic ventricular tachycardia is caused by mutation-linked defective conformational regulation of the ryanodine receptor. Circ Res 2010; 106:1413-24. [PMID: 20224043 DOI: 10.1161/circresaha.109.209312] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Catecholaminergic polymorphic ventricular tachycardia (CPVT) is caused by a single point mutation in a well-defined region of the cardiac type 2 ryanodine receptor (RyR)2. However, the underlying mechanism by which a single mutation in such a large molecule produces drastic effects on channel function remains unresolved. OBJECTIVE Using a knock-in (KI) mouse model with a human CPVT-associated RyR2 mutation (R2474S), we investigated the molecular mechanism by which CPVT is induced by a single point mutation within the RyR2. METHODS AND RESULTS The R2474S/+ KI mice showed no apparent structural or histological abnormalities in the heart, but they showed clear indications of other abnormalities. Bidirectional or polymorphic ventricular tachycardia was induced after exercise on a treadmill. The interaction between the N-terminal (amino acids 1 to 600) and central (amino acids 2000 to 2500) domains of the RyR2 (an intrinsic mechanism to close Ca(2+) channels) was weakened (domain unzipping). On protein kinase A-mediated phosphorylation of the RyR2, this domain unzipping further increased, resulting in a significant increase in the frequency of spontaneous Ca(2+) transients. cAMP-induced aberrant Ca(2+) release events (Ca(2+) sparks/waves) occurred at much lower sarcoplasmic reticulum Ca(2+) content as compared to the wild type. Addition of a domain-unzipping peptide, DPc10 (amino acids 2460 to 2495), to the wild type reproduced the aforementioned abnormalities that are characteristic of the R2474S/+ KI mice. Addition of DPc10 to the (cAMP-treated) KI cardiomyocytes produced no further effect. CONCLUSIONS A single point mutation within the RyR2 sensitizes the channel to agonists and reduces the threshold of luminal [Ca(2+)] for activation, primarily mediated by defective interdomain interaction within the RyR2.
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Affiliation(s)
- 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
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35
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Ryanodine receptor studies using genetically engineered mice. FEBS Lett 2010; 584:1956-65. [PMID: 20214899 DOI: 10.1016/j.febslet.2010.03.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 02/24/2010] [Accepted: 03/03/2010] [Indexed: 11/20/2022]
Abstract
Ryanodine receptors (RyR) regulate intracellular Ca(2+) release in many cell types and have been implicated in a number of inherited human diseases. Over the past 15 years genetically engineered mouse models have been developed to elucidate the role that RyRs play in physiology and pathophysiology. To date these models have implicated RyRs in fundamental biological processes including excitation-contraction coupling and long term plasticity as well as diseases including malignant hyperthermia, cardiac arrhythmias, heart failure, and seizures. In this review we summarize the RyR mouse models and how they have enhanced our understanding of the RyR channels and their roles in cellular physiology and disease.
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36
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Thomas NL, Maxwell C, Mukherjee S, Williams AJ. Ryanodine receptor mutations in arrhythmia: The continuing mystery of channel dysfunction. FEBS Lett 2010; 584:2153-60. [PMID: 20132818 DOI: 10.1016/j.febslet.2010.01.057] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 01/27/2010] [Accepted: 01/29/2010] [Indexed: 11/13/2022]
Abstract
Mutations in RyR2 are causative of an inherited disorder which often results in sudden cardiac death. Dysfunctional channel behaviour has been the subject of many investigations varying from single channel analysis through to complex animal models. This review discusses recent advances in the field, describes the controversy surrounding the exact consequences of RyR2 mutation and how the disparate data may be reconciled. This heterogeneity of function with respect to the effects of polymorphisms, phosphorylation, cytosolic and luminal Ca(2+) as well as inter-domain interactions may have important implications for the recent pharmaceutical therapies which have been put forward. We surmise that a comprehensive characterisation of mutations on a case-by-case basis may be beneficial for the development of specifically targeted therapies.
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Affiliation(s)
- N Lowri Thomas
- Department of Cardiology, Wales Heart Research Institute, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.
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Cerrone M, Napolitano C, Priori SG. Catecholaminergic polymorphic ventricular tachycardia: A paradigm to understand mechanisms of arrhythmias associated to impaired Ca(2+) regulation. Heart Rhythm 2009; 6:1652-9. [PMID: 19879546 DOI: 10.1016/j.hrthm.2009.06.033] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 07/25/2009] [Indexed: 11/30/2022]
Abstract
In the 8 years since the discovery of the genetic bases of catecholaminergic polymorphic ventricular tachycardia (CPVT), we have witnessed a remarkable improvement of knowledge on arrhythmogenic mechanisms involving disruption of cardiac Ca(2+) homeostasis. Studies on the consequences of RyR2 and CASQ2 mutations in cellular systems and mouse models have shed new light on pathways that are also implicated in arrhythmias occurring in highly prevalent diseases, such as heart failure. This research track has also led to the identification of therapeutic targets of potential clinical impact to abate the burden of sudden death in CPVT. Here, we review the current knowledge on the pathophysiology of CPVT also highlighting the existing controversies and possible future development.
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Affiliation(s)
- Marina Cerrone
- Cardiovascular Genetics, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York, USA
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38
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Blayney LM, Lai FA. Ryanodine receptor-mediated arrhythmias and sudden cardiac death. Pharmacol Ther 2009; 123:151-77. [PMID: 19345240 PMCID: PMC2704947 DOI: 10.1016/j.pharmthera.2009.03.006] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Accepted: 03/03/2009] [Indexed: 12/25/2022]
Abstract
The cardiac ryanodine receptor-Ca2+ release channel (RyR2) is an essential sarcoplasmic reticulum (SR) transmembrane protein that plays a central role in excitation–contraction coupling (ECC) in cardiomyocytes. Aberrant spontaneous, diastolic Ca2+ leak from the SR due to dysfunctional RyR2 contributes to the formation of delayed after-depolarisations, which are thought to underlie the fatal arrhythmia that occurs in both heart failure (HF) and in catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT is an inherited disorder associated with mutations in either the RyR2 or a SR luminal protein, calsequestrin. RyR2 shows normal function at rest in CPVT but the RyR2 dysfunction is unmasked by physical exercise or emotional stress, suggesting abnormal RyR2 activation as an underlying mechanism. Several potential mechanisms have been advanced to explain the dysfunctional RyR2 observed in HF and CPVT, including enhanced RyR2 phosphorylation status, altered RyR2 regulation at luminal/cytoplasmic sites and perturbed RyR2 intra/inter-molecular interactions. This review considers RyR2 dysfunction in the context of the structural and functional modulation of the channel, and potential therapeutic strategies to stabilise RyR2 function in cardiac pathology.
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Affiliation(s)
- Lynda M Blayney
- Wales Heart Research Institute, Cardiff University School of Medicine, Cardiff CF144XN, UK.
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Defective regulation of the ryanodine receptor induces hypertrophy in cardiomyocytes. Biochem Biophys Res Commun 2009; 380:493-7. [PMID: 19284993 DOI: 10.1016/j.bbrc.2009.01.152] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Accepted: 01/19/2009] [Indexed: 11/22/2022]
Abstract
Recent studies on cardiac hypertrophy animal model suggest that inter-domain interactions within the ryanodine receptor (RyR2) become defective concomitant with the development of hypertrophy (e.g. de-stabilization of the interaction between N-terminal and central domains of RyR2; T. Oda, M. Yano, T. Yamamoto, T. Tokuhisa, S. Okuda, M. Doi, T. Ohkusa, Y. Ikeda, S. Kobayashi, N. Ikemoto, M. Matsuzaki, Defective regulation of inter-domain interactions within the ryanodine receptor plays a key role in the pathogenesis of heart failure, Circulation 111 (2005) 3400-3410). To determine if de-stabilization of the inter-domain interaction in fact causes hypertrophy, we introduced DPc10 (a peptide corresponding to the G(2460)-P(2495) region of RyR2, which is known to de-stabilize the N-terminal/central domain interaction) into rat neonatal cardiomyocytes by mediation of peptide carrier BioPORTER. After incubation for 24h the peptide induced hypertrophy, as evidenced by significant increase in cell size and [(3)H]leucine uptake. K201 or dantrolene, the reagents known to correct the de-stabilized inter-domain interaction to a normal mode, prevented the DPc10-induced hypertrophy. These results suggest that disruption of the normal N-terminal/central inter-domain interaction within the RyR2 is a causative mechanism of cardiomyocyte hypertrophy.
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Katz G, Arad M, Eldar M. Catecholaminergic polymorphic ventricular tachycardia from bedside to bench and beyond. Curr Probl Cardiol 2009; 34:9-43. [PMID: 19068246 DOI: 10.1016/j.cpcardiol.2008.09.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a primary electrical myocardial disease characterized by exercise- and stress-related ventricular tachycardia manifested as syncope and sudden death. The disease has a heterogeneous genetic basis, with mutations in the cardiac Ryanodine Receptor channel (RyR2) gene accounting for an autosomal-dominant form (CPVT1) in approximately 50% and mutations in the cardiac calsequestrin gene (CASQ2) accounting for an autosomal-recessive form (CPVT2) in up to 2% of CPVT cases. Both RyR2 and calsequestrin are important participants in the cardiac cellular calcium homeostasis. We review the physiology of the cardiac calcium homeostasis, including the cardiac excitation contraction coupling and myocyte calcium cycling. The pathophysiology of cardiac arrhythmias related to myocyte calcium handling and the effects of different modulators are discussed. The putative derangements in myocyte calcium homeostasis responsible for CPVT, as well as the clinical manifestations and therapeutic options available, are described.
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Yano M, Yamamoto T, Kobayashi S, Matsuzaki M. Role of ryanodine receptor as a Ca²(+) regulatory center in normal and failing hearts. J Cardiol 2008; 53:1-7. [PMID: 19167631 DOI: 10.1016/j.jjcc.2008.10.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Accepted: 10/20/2008] [Indexed: 11/19/2022]
Abstract
Abnormal Ca²(+) cycling is important in various cardiac diseases. Evidence has accumulated that dysregulation of Ca²(+) release from the ryanodine receptor (RyR2) plays a significant role in cardiac dysfunction. Spontaneous Ca²(+) release through RyR2 during diastole decreases sarcoplasmic reticulum (SR) Ca²(+) content, and also induces delayed after depolarization (DAD) as a substrate for lethal arrhythmia. Several disease-linked mutations in the RyR have been reported in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) or arrythmogenic right ventricular cardiomyopathy type 2 (ARVC2). The unique distribution of these mutation sites has produced the concept that the interaction among the putative regulatory domains within the RyR may play a key role in regulating the channel opening, and that there seems to be a common abnormality in the channel disorder between heart failure and CPVT/ARVC2. We review here the considerable body of evidence regarding defective channel gating of RyR2 in the pathogenesis of heart failure and lethal arrhythmia.
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Affiliation(s)
- Masafumi Yano
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan.
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Tateishi H, Yano M, Mochizuki M, Suetomi T, Ono M, Xu X, Uchinoumi H, Okuda S, Oda T, Kobayashi S, Yamamoto T, Ikeda Y, Ohkusa T, Ikemoto N, Matsuzaki M. Defective domain-domain interactions within the ryanodine receptor as a critical cause of diastolic Ca2+ leak in failing hearts. Cardiovasc Res 2008; 81:536-45. [PMID: 18996969 DOI: 10.1093/cvr/cvn303] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS A domain peptide (DP) matching the Gly(2460)-Pro(2495) region of the cardiac type-2 ryanodine receptor (RyR2), DPc10, is known to mimic channel dysfunction associated with catecholaminergic polymorphic ventricular tachycardia (CPVT), owing to its interference in a normal interaction of the N-terminal (1-600) and central (2000-2500) domains (viz. domain unzipping). Using DPc10 and two other DPs harboring different mutation sites, we investigated the underlying mechanism of abnormal Ca(2+) cycling in failing hearts. METHODS AND RESULTS Sarcoplasmic reticulum (SR) vesicles and cardiomyocytes were isolated from dog left ventricular muscles for Ca(2+) leak and spark assays. The RyR2 moiety of the SR was fluorescently labelled with methylcoumarin acetate (MCA) using DPs corresponding to the 163-195 and 4090-4123 regions of RyR2 (DP163-195 and DP4090-4123, respectively) as site-directed carriers. Both DPs mediated a specific MCA fluorescence labelling of RyR2. Addition of either DP to the MCA-labelled SR induced domain unzipping, as evidenced by an increased accessibility of the bound MCA to a large-size fluorescence quencher. Both SR Ca(2+) leak and Ca(2+) spark frequency (SpF) were markedly increased in failing cardiomyocytes. Upon introduction of DP163-195 or DP4090-4123 into normal SR or cardiomyocytes, both Ca(2+) leak and SpF increased to the levels comparable with those of failing myocytes. K201 (JTV519) suppressed all of the effects induced by DP163-195 (domain unzipping and increased Ca(2+) leak and SpF) or those in failing cardiomyocytes, but did not suppress the effects induced by DP4090-4123. CONCLUSION Defective inter-domain interaction between N-terminal and central domains induces diastolic Ca(2+) leak, leading to heart failure and lethal arrhythmia. Mutation at the C-terminal region seen in CPVT does not seem to communicate with the aforementioned N-terminal and central inter-domain interaction, although spontaneous Ca(2+) leak is similarly induced.
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Affiliation(s)
- Hiroki Tateishi
- Division of Cardiology, Department of Medicine and Clinical Science, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505, Japan
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Liu N, Rizzi N, Boveri L, Priori SG. Ryanodine receptor and calsequestrin in arrhythmogenesis: what we have learnt from genetic diseases and transgenic mice. J Mol Cell Cardiol 2008; 46:149-59. [PMID: 19027025 DOI: 10.1016/j.yjmcc.2008.10.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 09/22/2008] [Accepted: 10/17/2008] [Indexed: 11/30/2022]
Abstract
The year 2001 has been pivotal for the identification of the molecular bases of catecholaminergic polymorphic ventricular tachycardia (CPVT): a life-threatening genetic disease that predisposes young individuals with normal cardiac structure to cardiac arrest. Interestingly CPVT has been linked to mutations in genes encoding the cardiac ryanodine receptor (RyR2) and cardiac calsequestrin (CASQ2): two fundamental proteins involved in regulation of intracellular Ca(2+) in cardiac myocytes. The critical role of the two proteins in the heart has attracted interests of the scientific community so that networks of investigators have embarked in translational studies to characterize in vitro and in vivo the mutant proteins. Overall in the last seven years the field has substantially advanced but considerable controversies still exist on the consequences of RyR2 and CASQ2 mutations and on the modalities by which they precipitate cardiac arrhythmias. With so many questions that need to be elucidated it is expected that in the near future the field will remain innovative and stimulating. In this review we will outline how research has advanced in the understanding of CPVT and we will present how the observations made have disclosed novel arrhythmogenic cascades that are likely to impact acquired heart diseases.
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Affiliation(s)
- Nian Liu
- Molecular Cardiology, Fondazione Salvatore Maugeri, Pavia, Italy
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Goddard CA, Ghais NS, Zhang Y, Williams AJ, Colledge WH, Grace AA, Huang CLH. Physiological consequences of the P2328S mutation in the ryanodine receptor (RyR2) gene in genetically modified murine hearts. Acta Physiol (Oxf) 2008; 194:123-40. [PMID: 18419777 PMCID: PMC2628439 DOI: 10.1111/j.1748-1716.2008.01865.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aim To explore the physiological consequences of the ryanodine receptor (RyR2)-P2328S mutation associated with catecholaminergic polymorphic ventricular tachycardia (CPVT). Methods We generated heterozygotic (RyR2p/s) and homozygotic (RyR2s/s) transgenic mice and studied Ca2+ signals from regularly stimulated, Fluo-3-loaded, cardiac myocytes. Results were compared with monophasic action potentials (MAPs) in Langendorff-perfused hearts under both regular and programmed electrical stimulation (PES). Results Evoked Ca2+ transients from wild-type (WT), heterozygote (RyR2p/s) and homozygote (RyR2s/s) myocytes had indistinguishable peak amplitudes with RyR2s/s showing subsidiary events. Adding 100 nm isoproterenol produced both ectopic peaks and subsidiary events in WT but not RyR2p/s and ectopic peaks and reduced amplitudes of evoked peaks in RyR2s/s. Regularly stimulated WT, RyR2p/s and RyR2s/s hearts showed indistinguishable MAP durations and refractory periods. RyR2p/s hearts showed non-sustained ventricular tachycardias (nsVTs) only with PES. Both nsVTs and sustained VTs (sVTs) occurred with regular stimuli and PES with isoproterenol treatment. RyR2s/s hearts showed higher incidences of nsVTs before but mainly sVTs after introduction of isoproterenol with both regular stimuli and PES, particularly at higher pacing frequencies. Additionally, intrinsically beating RyR2s/s showed extrasystolic events often followed by spontaneous sVT. Conclusion The RyR2-P2328S mutation results in marked alterations in cellular Ca2+ homeostasis and arrhythmogenic properties resembling CPVT with greater effects in the homozygote than the heterozygote demonstrating an important gene dosage effect.
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Affiliation(s)
- C A Goddard
- Physiological Laboratory, University of Cambridge, Cambridge, UK
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Györke S. Molecular basis of catecholaminergic polymorphic ventricular tachycardia. Heart Rhythm 2008; 6:123-9. [PMID: 19121813 DOI: 10.1016/j.hrthm.2008.09.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 09/11/2008] [Indexed: 11/27/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a malignant arrhythmia syndrome linked to mutations in the cardiac ryanodine receptor (RyR2) and calsequestrin (CASQ2). RyR2 and CASQ2 are parts of the multimolecular Ca(2+) release channel complex that is present on the sarcoplasmic reticulum (SR) to support myocyte Ca(2+) cycling and contractile activity. Whereas RyR2 operates as a Ca(2+) release channel, the SR Ca(2+) binding protein CASQ2 plays a dual role by serving as a SR Ca(2+) buffer and by regulating RyR2 function. Essential to stable Ca(2+) cycling, SR luminal Ca(2+)-dependent control of RyR2 activity by CASQ2 contributes to RyR2 deactivation and to the development of a temporary refractory state that occurs after each Ca(2+) release. Accumulating evidence suggests that the CPVT mutations act by reducing the extent and shortening the duration of Ca(2+) signaling refractoriness, thereby promoting untimely SR Ca(2+) release and arrhythmogenic delayed afterdepolarizations in cardiac myocytes. Similar mechanisms may apply to arrhythmias during various conditions, including heart failure and ischemic heart disease, associated with acquired defects in components of the Ca(2+) release channel complex.
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Affiliation(s)
- Sandor Györke
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, Ohio 43210, USA.
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Yano M, Yamamoto T, Kobayashi S, Ikeda Y, Matsuzaki M. Defective Ca2+ cycling as a key pathogenic mechanism of heart failure. Circ J 2008; 72 Suppl A:A22-30. [PMID: 18772523 DOI: 10.1253/circj.cj-08-0070] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Structural and functional alterations in the Ca(2+) regulatory proteins present in the sarcoplasmic reticulum (SR) have recently been shown to play a crucial role in the pathogenesis of heart failure (HF), and lethal arrhythmia as well. Chronic activation of the sympathetic nervous system induces abnormalities in both the function and structure of these proteins. For instance, the diastolic Ca(2+) leak through the SR Ca(2+) release channel (ryanodine receptor) reduces the SR Ca(2+) content, inducing contractile dysfunction. Moreover, the Ca(2+) leak provides a substrate for delayed after depolarization that leads to lethal arrhythmia. There is a considerable body of evidence regarding the role of Ca(2+) cycling abnormality in HF.
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Affiliation(s)
- Masafumi Yano
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, Ube, Japan.
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47
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Abstract
Abnormal intracellular Ca(2+) handling by the sarcoplasmic reticulum (SR) is a critical factor in the development of heart failure (HF). Not only decreased Ca(2+) uptake, but also uncoordinated Ca(2+) release plays a significant role in contractile and relaxation dysfunction. Spontaneous Ca(2+) release through ryanodine receptor (RyR) 2, a huge tetrameric protein, during diastole leads to a decrease in the SR Ca(2+) content, and also triggers delayed after depolarization that is a substrate for lethal arrhythmia. Several disease-linked mutations of RyR have been reported in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) or arrhythmogenic right ventricular cardiomyopathy type 2 (ARVC2). The unique distribution of these mutation sites has lead to the concept that an interaction among the putative regulatory domains within RyR may play a key role in regulating channel opening, and that there seems to be a common abnormality in the channel disorder of HF and CPVT/ARVC2. Recent knowledge gained from pathological conditions may lead to the development of a new therapeutic strategy for the treatment of HF or cardiac arrhythmia.
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Affiliation(s)
- Masafumi Yano
- Department of Medicine and Clinical Science, Division of Cardiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube 755-8505, Japan.
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48
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Abstract
Ventricular arrhythmias deteriorating into sudden cardiac death are a major cause of mortality worldwide. The recent linkage of a genetic form of cardiac arrhythmia to mutations in the gene encoding RyR2 (ryanodine receptor 2) has uncovered an important role of this SR (sarcoplasmic reticulum) calcium release channel in triggering arrhythmias. Mutant RyR2 channels give rise to spontaneous release of calcium (Ca(2+)) from the SR during diastole, which enhances the probability of ventricular arrhythmias. Several molecular mechanisms have been proposed to explain the gain-of-function phenotype observed in mutant RyR2 channels. Despite considerable differences between the models discussed in the present review, each predicts spontaneous diastolic Ca(2+) leak from the SR due to incomplete closure of the RyR2 channel. Enhanced SR Ca(2+) leak is also observed in common structural diseases of the heart, such as heart failure. In heart failure, defective channel regulation in the absence of inherited mutations may also increase SR Ca(2+) leak and initiate cardiac arrhythmias. Therefore inhibition of diastolic Ca(2+) leak through SR Ca(2+) release channels has emerged as a new and promising therapeutic target for cardiac arrhythmias.
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Mohler PJ, Wehrens XHT. Mechanisms of human arrhythmia syndromes: abnormal cardiac macromolecular interactions. Physiology (Bethesda) 2008; 22:342-50. [PMID: 17928548 DOI: 10.1152/physiol.00018.2007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Many cardiac ion channels exist within macromolecular signaling complexes, comprised of pore-forming subunits that associate with auxiliary subunits, regulatory enzymes, and targeting proteins. This complex protein assembly ensures proper modulation of channel activity and ion homeostasis. The association of genetic defects in regulatory and targeting proteins to inherited arrhythmia syndromes has led to a better understanding of the critical role these proteins play in ion channel modulation.
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Affiliation(s)
- Peter J Mohler
- Department of Internal Medicine, Division of Cardiology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
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Seidler T, Hasenfuss G, Maier LS. Targeting altered calcium physiology in the heart: translational approaches to excitation, contraction, and transcription. Physiology (Bethesda) 2008; 22:328-34. [PMID: 17928546 DOI: 10.1152/physiol.00015.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Calcium (Ca) is essential for excitation-contraction coupling. At the same time, Ca is of pivotal importance as a second messenger in cardiac signal transduction, where it regulates cardiac growth and function by activation of kinases and phosphatases, ultimately driving transcriptional responses and feeding back on Ca handling proteins, a phenomenon termed excitation-transcription coupling. Cardiac Ca homeostasis thus needs to be maintained via a delicate interplay of proteins to allow physiological function and adaptation, whereas disturbed Ca-handling and Ca-dependent signaling are hallmarks of heart failure. In this review, we will discuss the most recent mechanistic findings in Ca-handling and Ca-signaling proteins in the development of cardiac pathology with a focus on translational aspects.
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Affiliation(s)
- Tim Seidler
- Department of Cardiology and Pneumology, Heart Center Georg-August-University Göttingen, Göttingen, Germany
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