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Minato H, Endo R, Kurata Y, Notsu T, Kinugasa Y, Wakimizu T, Tsuneto M, Shirayoshi Y, Ninomiya H, Yamamoto K, Hisatome I, Otsuki A. Azelnidipine protects HL-1 cardiomyocytes from hypoxia/reoxygenation injury by enhancement of NO production independently of effects on gene expression. Heart Vessels 2024:10.1007/s00380-024-02415-4. [PMID: 38797744 DOI: 10.1007/s00380-024-02415-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 05/15/2024] [Indexed: 05/29/2024]
Abstract
It remains to be elucidated whether Ca2+ antagonists induce pharmacological preconditioning to protect the heart against ischemia/reperfusion injury. The aim of this study was to determine whether and how pretreatment with a Ca2+ antagonist, azelnidipine, could protect cardiomyocytes against hypoxia/reoxygenation (H/R) injury in vitro. Using HL-1 cardiomyocytes, we studied effects of azelnidipine on NO synthase (NOS) expression, NO production, cell death and apoptosis during H/R. Action potential durations (APDs) were determined by the whole-cell patch-clamp technique. Azelnidipine enhanced endothelial NOS phosphorylation and NO production in HL-1 cells under normoxia, which was abolished by a heat shock protein 90 inhibitor, geldanamycin, and an antioxidant, N-acetylcysteine. Pretreatment with azelnidipine reduced cell death and shortened APDs during H/R. These effects of azelnidipine were diminished by a NOS inhibitor, L-NAME, but were influenced by neither a T-type Ca2+ channel inhibitor, NiCl2, nor a N-type Ca2+ channel inhibitor, ω-conotoxin. The azelnidipine-induced reduction in cell death was not significantly enhanced by either additional azelnidipine treatment during H/R or increasing extracellular Ca2+ concentrations. RNA sequence (RNA-seq) data indicated that azelnidipine-induced attenuation of cell death, which depended on enhanced NO production, did not involve any significant modifications of gene expression responsible for the NO/cGMP/PKG pathway. We conclude that pretreatment with azelnidipine protects HL-1 cardiomyocytes against H/R injury via NO-dependent APD shortening and L-type Ca2+ channel blockade independently of effects on gene expression.
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Affiliation(s)
- Hiroyuki Minato
- Department of Anesthesiology, Tottori University Faculty of Medicine, 86 Nishi-Cho, Yonago, 683-8503, Japan
| | - Ryo Endo
- Department of Anesthesiology, Tottori University Faculty of Medicine, 86 Nishi-Cho, Yonago, 683-8503, Japan
| | - Yasutaka Kurata
- Department of Physiology II, Kanazawa Medical University, Ishikawa, 920-0293, Japan.
| | - Tomomi Notsu
- Department of Genomic Medicine and Regenerative Therapy, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Yoshiharu Kinugasa
- Department of Cardiovascular Medicine, and Endocrinology and Metabolism, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Takayuki Wakimizu
- Center for iPS Cell Research and Application, Kyoto University, Kyoto, 606-8507, Japan
- Takeda-CiRA Joint Program (T-CiRA), Fujisawa, 251-8555, Japan
| | - Motokazu Tsuneto
- Department of Genomic Medicine and Regenerative Therapy, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Yasuaki Shirayoshi
- Department of Genomic Medicine and Regenerative Therapy, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Haruaki Ninomiya
- Department of Biological Regulation, Tottori University, Yonago, 683-8503, Japan
| | - Kazuhiro Yamamoto
- Department of Cardiovascular Medicine, and Endocrinology and Metabolism, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Ichiro Hisatome
- Department of Cardiology, NHO Yonago Medical Center, Yonago, 683-0006, Japan
| | - Akihiro Otsuki
- Department of Anesthesiology, Tottori University Faculty of Medicine, 86 Nishi-Cho, Yonago, 683-8503, Japan
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Neeman-Egozi S, Livneh I, Dolgopyat I, Nussinovitch U, Milman H, Cohen N, Eisen B, Ciechanover A, Binah O. Stress-Induced Proteasome Sub-Cellular Translocation in Cardiomyocytes Causes Altered Intracellular Calcium Handling and Arrhythmias. Int J Mol Sci 2024; 25:4932. [PMID: 38732146 PMCID: PMC11084437 DOI: 10.3390/ijms25094932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/18/2024] [Accepted: 04/24/2024] [Indexed: 05/13/2024] Open
Abstract
The ubiquitin-proteasome system (UPS) is an essential mechanism responsible for the selective degradation of substrate proteins via their conjugation with ubiquitin. Since cardiomyocytes have very limited self-renewal capacity, as they are prone to protein damage due to constant mechanical and metabolic stress, the UPS has a key role in cardiac physiology and pathophysiology. While altered proteasomal activity contributes to a variety of cardiac pathologies, such as heart failure and ischemia/reperfusion injury (IRI), the environmental cues affecting its activity are still unknown, and they are the focus of this work. Following a recent study by Ciechanover's group showing that amino acid (AA) starvation in cultured cancer cell lines modulates proteasome intracellular localization and activity, we tested two hypotheses in human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs, CMs): (i) AA starvation causes proteasome translocation in CMs, similarly to the observation in cultured cancer cell lines; (ii) manipulation of subcellular proteasomal compartmentalization is associated with electrophysiological abnormalities in the form of arrhythmias, mediated via altered intracellular Ca2+ handling. The major findings are: (i) starving CMs to AAs results in proteasome translocation from the nucleus to the cytoplasm, while supplementation with the aromatic amino acids tyrosine (Y), tryptophan (W) and phenylalanine (F) (YWF) inhibits the proteasome recruitment; (ii) AA-deficient treatments cause arrhythmias; (iii) the arrhythmias observed upon nuclear proteasome sequestration(-AA+YWF) are blocked by KB-R7943, an inhibitor of the reverse mode of the sodium-calcium exchanger NCX; (iv) the retrograde perfusion of isolated rat hearts with AA starvation media is associated with arrhythmias. Collectively, our novel findings describe a newly identified mechanism linking the UPS to arrhythmia generation in CMs and whole hearts.
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Affiliation(s)
- Shunit Neeman-Egozi
- Department of Physiology, Biophysics and Systems Biology, Rappaport Faculty of Medicine, Technion—Israel Institute of Technology, Haifa 3190601, Israel; (S.N.-E.); (B.E.)
| | - Ido Livneh
- The Rappaport-Technion Integrated Cancer Center (R-TICC) and The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 319060, Israel; (I.L.); (N.C.)
| | - Irit Dolgopyat
- Department of Physiology, Biophysics and Systems Biology, Rappaport Faculty of Medicine, Technion—Israel Institute of Technology, Haifa 3190601, Israel; (S.N.-E.); (B.E.)
| | - Udi Nussinovitch
- Department of Cardiology, Edith Wolfson Medical Center, Holon 5822012, Israel
- The Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Helena Milman
- Department of Physiology, Biophysics and Systems Biology, Rappaport Faculty of Medicine, Technion—Israel Institute of Technology, Haifa 3190601, Israel; (S.N.-E.); (B.E.)
| | - Nadav Cohen
- The Rappaport-Technion Integrated Cancer Center (R-TICC) and The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 319060, Israel; (I.L.); (N.C.)
| | - Binyamin Eisen
- Department of Physiology, Biophysics and Systems Biology, Rappaport Faculty of Medicine, Technion—Israel Institute of Technology, Haifa 3190601, Israel; (S.N.-E.); (B.E.)
| | - Aaron Ciechanover
- The Rappaport-Technion Integrated Cancer Center (R-TICC) and The Rappaport Faculty of Medicine and Research Institute, Technion-Israel Institute of Technology, Haifa 319060, Israel; (I.L.); (N.C.)
| | - Ofer Binah
- Department of Physiology, Biophysics and Systems Biology, Rappaport Faculty of Medicine, Technion—Israel Institute of Technology, Haifa 3190601, Israel; (S.N.-E.); (B.E.)
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Santoro F, Mango F, Mallardi A, D'Alessandro D, Casavecchia G, Gravina M, Correale M, Brunetti ND. Arrhythmic Risk Stratification among Patients with Hypertrophic Cardiomyopathy. J Clin Med 2023; 12:jcm12103397. [PMID: 37240503 DOI: 10.3390/jcm12103397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/07/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a cardiac muscle disorder characterized by generally asymmetric abnormal hypertrophy of the left ventricle without abnormal loading conditions (such as hypertension or valvular heart disease) accounting for the left ventricular wall thickness or mass. The incidence of sudden cardiac death (SCD) in HCM patients is about 1% yearly in adults, but it is far higher in adolescence. HCM is the most frequent cause of death in athletes in the Unites States of America. HCM is an autosomal-dominant genetic cardiomyopathy, and mutations in the genes encoding sarcomeric proteins are identified in 30-60% of cases. The presence of this genetic mutation carries more than 2-fold increased risk for all outcomes, including ventricular arrhythmias. Genetic and myocardial substrate, including fibrosis and intraventricular dispersion of conduction, ventricular hypertrophy and microvascular ischemia, increased myofilament calcium sensitivity and abnormal calcium handling, all play a role as arrhythmogenic determinants. Cardiac imaging studies provide important information for risk stratification. Transthoracic echocardiography can be helpful to evaluate left ventricular (LV) wall thickness, LV outflow-tract gradient and left atrial size. Additionally, cardiac magnetic resonance can evaluate the prevalence of late gadolinium enhancement, which when higher than 15% of LV mass is a prognostic maker of SCD. Age, family history of SCD, syncope and non-sustained ventricular tachycardia at Holter ECG have also been validated as independent prognostic markers of SCD. Arrhythmic risk stratification in HCM requires careful evaluation of several clinical aspects. Symptoms combined with electrocardiogram, cardiac imaging tools and genetic counselling are the modern cornerstone for proper risk stratification.
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Affiliation(s)
- Francesco Santoro
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Federica Mango
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Adriana Mallardi
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Damiano D'Alessandro
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Grazia Casavecchia
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Matteo Gravina
- Radiology Unit, University Polyclinic Hospital of Foggia, 71100 Foggia, Italy
| | - Michele Correale
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | - Natale Daniele Brunetti
- Cardiology Unit, Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
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Li P, Kurata Y, Taufiq F, Kuwabara M, Ninomiya H, Higaki K, Tsuneto M, Shirayoshi Y, Lanaspa MA, Hisatome I. Kv1.5 channel mediates monosodium urate-induced activation of NLRP3 inflammasome in macrophages and arrhythmogenic effects of urate on cardiomyocytes. Mol Biol Rep 2022; 49:5939-5952. [PMID: 35368226 PMCID: PMC9270276 DOI: 10.1007/s11033-022-07378-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 03/15/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND Gout is usually found in patients with atrial fibrillation (AF). K+ efflux is a common trigger of NLRP3 inflammasome activation which is involved in the pathogenesis of AF. We investigated the role of the K+ channel Kv1.5 in monosodium urate crystal (MSU)-induced activation of the NLRP3 inflammasome and electrical remodeling in mouse and human macrophages J774.1 and THP-1, and mouse atrial myocytes HL-1. METHODS AND RESULTS Macrophages, primed with lipopolysaccharide (LPS), were stimulated by MSU. HL-1 cells were incubated with the conditioned medium (CM) from MSU-stimulated macrophages. Western blot, ELISA and patch clamp were used. MSU induced caspase-1 expression in LPS-primed J774.1 cells and IL-1β secretion, suggesting NLRP3 inflammasome activation. A selective Kv1.5 inhibitor, diphenyl phosphine oxide-1 (DPO-1), and siRNAs against Kv1.5 suppressed the levels of caspase-1 and IL-1β. MSU reduced intracellular K+ concentration which was prevented by DPO-1 and siRNAs against Kv1.5. MSU increased expression of Hsp70, and Kv1.5 on the plasma membrane. siRNAs against Hsp70 were suppressed but heat shock increased the expression of Hsp70, caspase-1, IL-1β, and Kv1.5 in MSU-stimulated J774.1 cells. The CM from MSU-stimulated macrophages enhanced the expression of caspase-1, IL-1β and Kv1.5 with increased Kv1.5-mediated currents that shortened action potential duration in HL-1 cells. These responses were abolished by DPO-1 and a siRNA against Kv1.5. CONCLUSIONS Kv1.5 regulates MSU-induced activation of NLRP3 inflammasome in macrophages. MSUrelated activation of NLRP3 inflammasome and electrical remodeling in HL-1 cells are via macrophages. Kv1.5 may have therapeutic value for diseases related to gout-induced activation of the NLRP3 inflammsome, including AF.
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Affiliation(s)
- Peili Li
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University, 36-1, Nishimachi, Yonago, Tottori, 683-8504, Japan.
| | - Yasutaka Kurata
- Department of Physiology II, Kanazawa Medical University, Kahoku, Ishikawa, 920-0293, Japan
| | - Fikri Taufiq
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University, 36-1, Nishimachi, Yonago, Tottori, 683-8504, Japan
| | - Masanari Kuwabara
- Intensive Care Unit and Department of Cardiology, Toranomon Hospital, Tokyo, 105-8470, Japan
| | - Haruaki Ninomiya
- Department of Biological Regulation, Tottori University, Yonago, 683-8504, Japan
| | - Katsumi Higaki
- Research Center for Bioscience and Technology, Tottori University, Yonago, 683-8504, Japan
| | - Motokazu Tsuneto
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University, 36-1, Nishimachi, Yonago, Tottori, 683-8504, Japan
| | - Yasuaki Shirayoshi
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University, 36-1, Nishimachi, Yonago, Tottori, 683-8504, Japan
| | - Miguel A Lanaspa
- Division of Renal Diseases and Hypertension, School of Medicine, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Ichiro Hisatome
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University, 36-1, Nishimachi, Yonago, Tottori, 683-8504, Japan
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Physiological Overview of the Potential Link between the UPS and Ca2+ Signaling. Antioxidants (Basel) 2022; 11:antiox11050997. [PMID: 35624861 PMCID: PMC9137615 DOI: 10.3390/antiox11050997] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/10/2022] [Accepted: 05/17/2022] [Indexed: 02/04/2023] Open
Abstract
The ubiquitin–proteasome system (UPS) is the main proteolytic pathway by which damaged target proteins are degraded after ubiquitination and the recruit of ubiquitinated proteins, thus regulating diverse physiological functions and the maintenance in various tissues and cells. Ca2+ signaling is raised by oxidative or ER stress. Although the basic function of the UPS has been extensively elucidated and has been continued to define its mechanism, the precise relationship between the UPS and Ca2+ signaling remains unclear. In the present review, we describe the relationship between the UPS and Ca2+ signaling, including Ca2+-associated proteins, to understand the end point of oxidative stress. The UPS modulates Ca2+ signaling via the degradation of Ca2+-related proteins, including Ca2+ channels and transporters. Conversely, the modulation of UPS is driven by increases in the intracellular Ca2+ concentration. The multifaceted relationship between the UPS and Ca2+ plays critical roles in different tissue systems. Thus, we highlight the potential crosstalk between the UPS and Ca2+ signaling by providing an overview of the UPS in different organ systems and illuminating the relationship between the UPS and autophagy.
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6
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Suay-Corredera C, Alegre-Cebollada J. The mechanics of the heart: zooming in on hypertrophic cardiomyopathy and cMyBP-C. FEBS Lett 2022; 596:703-746. [PMID: 35224729 DOI: 10.1002/1873-3468.14301] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 11/10/2022]
Abstract
Hypertrophic cardiomyopathy (HCM), a disease characterized by cardiac muscle hypertrophy and hypercontractility, is the most frequently inherited disorder of the heart. HCM is mainly caused by variants in genes encoding proteins of the sarcomere, the basic contractile unit of cardiomyocytes. The most frequently mutated among them is MYBPC3, which encodes cardiac myosin-binding protein C (cMyBP-C), a key regulator of sarcomere contraction. In this review, we summarize clinical and genetic aspects of HCM and provide updated information on the function of the healthy and HCM sarcomere, as well as on emerging therapeutic options targeting sarcomere mechanical activity. Building on what is known about cMyBP-C activity, we examine different pathogenicity drivers by which MYBPC3 variants can cause disease, focussing on protein haploinsufficiency as a common pathomechanism also in nontruncating variants. Finally, we discuss recent evidence correlating altered cMyBP-C mechanical properties with HCM development.
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Yang QL, Zuo L, Ma ZL, Lei CH, Zhu XL, Wang XY, Wang B, Zhao XL, Zhang J, Wang Y, Zhang YM, Liu LW. Gender- and age-related differences in distinct phenotypes of hypertrophic cardiomyopathy-associated mutation MYBPC3-E334K. Heart Vessels 2021; 36:1525-1535. [PMID: 33830315 DOI: 10.1007/s00380-021-01834-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/12/2021] [Indexed: 11/30/2022]
Abstract
The mutation MYBPC3-E334K is a culprit mutation of hypertrophic cardiomyopathy (HCM). The pathogenicity of MYBPC3-E334K is conflicting in ClinVar because of the limited segregation data and the relatively high frequency in gnomAD (0.03% overall, with 0.3% in East Asians and 0.8% in Japanese). The main aim is to clarify the clinical importance and phenotype-genotype correlations in subjects with or without MYBPC3-E334K alone. The prevalence of MYBPC3-E334K was sequenced in 1017 HCM unrelated probands. The clinical features, morphology phenotypes, and electrical phenotypes were further analyzed according to the phenotype and genotype status in families with single-mutation MYBPC3-E334K. Nine of 1017 (0.88%) unrelated HCM probands were detected harboring MYBPC3-E334K, and three of them harbored a second variant in sarcomere protein gene. Family study and co-segregation analyses indicated that patients with single-mutation MYBPC3-E334K showed autosomal dominant mode of inheritance with incomplete penetrance. The overall disease penetrance was 52.6%, and the disease penetrance was higher in males than in females (100% in men vs 25% in women, p = 0.003). The mean age at diagnosis of males was approximately 25 years younger than females (36.57 ± 18.65 vs 62.33 ± 12.10, p = 0.062). The variant MYBPC3-E334K was classified as a likely pathogenic variant, and a second sarcomere variant did not reveal obvious cumulative effects. The patients harboring single-mutation MYBPC3-E334K had incomplete penetrance, and males demonstrated higher penetrance and early onset HCM than females. A second sarcomere variant did not reveal obvious cumulative effects.
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Affiliation(s)
- Qian-Li Yang
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, Shaanxi, China
| | - Lei Zuo
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, Shaanxi, China
| | - Zhi-Ling Ma
- Department of Cardiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Chang-Hui Lei
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, Shaanxi, China
| | - Xiao-Li Zhu
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, Shaanxi, China
| | - Xuan-Ying Wang
- Department of Neurology, The Central Theater Command Air Force Hospital of People's Liberation Army, Datong, Shanxi, China
| | - Bo Wang
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, Shaanxi, China
| | - Xue-Li Zhao
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, Shaanxi, China
| | - Juan Zhang
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, Shaanxi, China
| | - Yue Wang
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, Shaanxi, China
| | - Yan-Min Zhang
- Department of Cardiology, Shaanxi Institute for Pediatric Diseases, Affiliate Children's Hospital of Xi'an Jiaotong University, No. 69, Xijuyuan land, Xi'an, Shaanxi, China.
| | - Li-Wen Liu
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, 127# Changle West Road, Xi'an, Shaanxi, China.
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Arif M, Nabavizadeh P, Song T, Desai D, Singh R, Bazrafshan S, Kumar M, Wang Y, Gilbert RJ, Dhandapany PS, Becker RC, Kranias EG, Sadayappan S. Genetic, clinical, molecular, and pathogenic aspects of the South Asian-specific polymorphic MYBPC3 Δ25bp variant. Biophys Rev 2020; 12:1065-1084. [PMID: 32656747 PMCID: PMC7429610 DOI: 10.1007/s12551-020-00725-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/03/2020] [Indexed: 02/06/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a cardiac genetic disease characterized by ventricular enlargement, diastolic dysfunction, and increased risk for sudden cardiac death. Sarcomeric genetic defects are the predominant known cause of HCM. In particular, mutations in the myosin-binding protein C gene (MYBPC3) are associated with ~ 40% of all HCM cases in which a genetic basis has been established. A decade ago, our group reported a 25-base pair deletion in intron 32 of MYBPC3 (MYBPC3Δ25bp) that is uniquely prevalent in South Asians and is associated with autosomal dominant cardiomyopathy. Although our studies suggest that this deletion results in left ventricular dysfunction, cardiomyopathies, and heart failure, the precise mechanism by which this variant predisposes to heart disease remains unclear. Increasingly appreciated, however, is the contribution of secondary risk factors, additional mutations, and lifestyle choices in augmenting or modifying the HCM phenotype in MYBPC3Δ25bp carriers. Therefore, the goal of this review article is to summarize the current research dedicated to understanding the molecular pathophysiology of HCM in South Asians with the MYBPC3Δ25bp variant. An emphasis is to review the latest techniques currently applied to explore the MYBPC3Δ25bp pathogenesis and to provide a foundation for developing new diagnostic strategies and advances in therapeutics.
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Affiliation(s)
- Mohammed Arif
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA.
| | - Pooneh Nabavizadeh
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Taejeong Song
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Darshini Desai
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Rohit Singh
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Sholeh Bazrafshan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Mohit Kumar
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Yigang Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati, College of Medicine, Cincinnati, OH, 45267, USA
| | - Richard J Gilbert
- Research Service, Providence VA Medical Center, Providence, RI, 02908, USA
| | - Perundurai S Dhandapany
- Centre for Cardiovascular Biology and Disease, Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore, India
- The Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
- Department of Medicine, Oregon Health and Science University, Portland, OR, USA
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Richard C Becker
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, 45267, USA
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
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9
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Kuster DWD, Lynch TL, Barefield DY, Sivaguru M, Kuffel G, Zilliox MJ, Lee KH, Craig R, Namakkal-Soorappan R, Sadayappan S. Altered C10 domain in cardiac myosin binding protein-C results in hypertrophic cardiomyopathy. Cardiovasc Res 2020; 115:1986-1997. [PMID: 31050699 DOI: 10.1093/cvr/cvz111] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/04/2019] [Accepted: 04/25/2019] [Indexed: 12/12/2022] Open
Abstract
AIMS A 25-base pair deletion in the cardiac myosin binding protein-C (cMyBP-C) gene (MYBPC3), proposed to skip exon 33, modifies the C10 domain (cMyBP-CΔC10mut) and is associated with hypertrophic cardiomyopathy (HCM) and heart failure, affecting approximately 100 million South Asians. However, the molecular mechanisms underlying the pathogenicity of cMyBP-CΔC10mutin vivo are unknown. We hypothesized that expression of cMyBP-CΔC10mut exerts a poison polypeptide effect leading to improper assembly of cardiac sarcomeres and the development of HCM. METHODS AND RESULTS To determine whether expression of cMyBP-CΔC10mut is sufficient to cause HCM and contractile dysfunction in vivo, we generated transgenic (TG) mice having cardiac-specific protein expression of cMyBP-CΔC10mut at approximately half the level of endogenous cMyBP-C. At 12 weeks of age, significant hypertrophy was observed in TG mice expressing cMyBP-CΔC10mut (heart weight/body weight ratio: 4.43 ± 0.11 mg/g non-transgenic (NTG) vs. 5.34 ± 0.25 mg/g cMyBP-CΔC10mut, P < 0.05). Furthermore, haematoxylin and eosin, Masson's trichrome staining, as well as second-harmonic generation imaging revealed the presence of significant fibrosis and a greater relative nuclear area in cMyBP-CΔC10mut hearts compared with NTG controls. M-mode echocardiography analysis revealed hypercontractile hearts (EF: 53.4%±2.9% NTG vs. 66.4% ± 4.7% cMyBP-CΔC10mut; P < 0.05) and early diastolic dysfunction (E/E': 28.7 ± 3.7 NTG vs. 46.3 ± 8.4 cMyBP-CΔC10mut; P < 0.05), indicating the presence of an HCM phenotype. To assess whether these changes manifested at the myofilament level, contractile function of single skinned cardiomyocytes was measured. Preserved maximum force generation and increased Ca2+-sensitivity of force generation were observed in cardiomyocytes from cMyBP-CΔC10mut mice compared with NTG controls (EC50: 3.6 ± 0.02 µM NTG vs. 2.90 ± 0.01 µM cMyBP-CΔC10mut; P < 0.0001). CONCLUSION Expression of cMyBP-C protein with a modified C10 domain is sufficient to cause contractile dysfunction and HCM in vivo.
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Affiliation(s)
- Diederik W D Kuster
- Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA.,Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Thomas L Lynch
- Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
| | - David Y Barefield
- Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA.,Center for Genetic Medicine, Northwestern University, Chicago, IL, USA
| | - Mayandi Sivaguru
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Gina Kuffel
- Public Health Sciences, Loyola University Chicago, Maywood, IL, USA
| | | | - Kyoung Hwan Lee
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Roger Craig
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Rajasekaran Namakkal-Soorappan
- Molecular and Cellular Pathology, Department of Pathology, School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sakthivel Sadayappan
- Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA.,Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, USA
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10
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Minato H, Hisatome I, Kurata Y, Notsu T, Nakasone N, Ninomiya H, Hamada T, Tomomori T, Okamura A, Miake J, Tsuneto M, Shirayoshi Y, Endo R, Otsuki A, Okada F, Inagaki Y. Pretreatment with cilnidipine attenuates hypoxia/reoxygenation injury in HL-1 cardiomyocytes through enhanced NO production and action potential shortening. Hypertens Res 2020; 43:380-388. [PMID: 31942044 DOI: 10.1038/s41440-019-0391-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/15/2019] [Accepted: 12/03/2019] [Indexed: 11/09/2022]
Abstract
Myocardial ischemia/reperfusion injury worsens in the absence of nitric oxide synthase (NOS). Cilnidipine, a Ca2+ channel blocker, has been reported to activate endothelial NOS (eNOS) and increases nitric oxide (NO) in vascular endothelial cells. We examined whether pretreatment with cilnidipine could attenuate cardiac cell deaths including apoptosis caused by hypoxia/reoxygenation (H/R) injury. HL-1 mouse atrial myocytes as well as H9c2 rat ventricular cells were exposed to H/R, and cell viability was evaluated by an autoanalyzer and flow cytometry; eNOS expression, NO production, and electrophysiological properties were also evaluated by western blotting, colorimetry, and patch clamping, respectively, in the absence and presence of cilnidipine. Cilnidipine enhanced phosphorylation of eNOS and NO production in a concentration-dependent manner, which was abolished by siRNAs against eNOS or an Hsp90 inhibitor, geldanamycin. Pretreatment with cilnidipine attenuated cell deaths including apoptosis during H/R; this effect was reproduced by an NO donor and a xanthine oxidase inhibitor. The NOS inhibitor L-NAME abolished the protective action of cilnidipine. Pretreatment with cilnidipine also attenuated H9c2 cell death during H/R. Additional cilnidipine treatment during H/R did not significantly enhance its protective action. There was no significant difference in the protective effect of cilnidipine under normal and high Ca2+ conditions. Action potential duration (APD) of HL-1 cells was shortened by cilnidipine, with this shortening augmented after H/R. L-NAME attenuated the APD shortening caused by cilnidipine. These findings indicate that cilnidipine enhances NO production, shortens APD in part by L-type Ca2+ channel block, and thereby prevents HL-1 cell deaths during H/R.
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Affiliation(s)
- Hiroyuki Minato
- Department of Anesthesiology and Critical Care Medicine, Tottori University Faculty of Medicine, 86 Nishi-cho, Yonago, 683-8503, Japan
| | - Ichiro Hisatome
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science, 86 Nishi-cho, Yonago, 683-8503, Japan
| | - Yasutaka Kurata
- Department of Physiology II, Kanazawa Medical University, Ishikawa, 920-0268, Japan.
| | - Tomomi Notsu
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science, 86 Nishi-cho, Yonago, 683-8503, Japan
| | - Naoe Nakasone
- Department of Biological Regulation, Tottori University, Yonago, 683-8503, Japan
| | - Haruaki Ninomiya
- Department of Biological Regulation, Tottori University, Yonago, 683-8503, Japan
| | - Toshihiro Hamada
- Department of Community-Based Family Medicine, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Takuya Tomomori
- Department of Molecular Medicine and Therapeutics, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Akihiro Okamura
- Department of Molecular Medicine and Therapeutics, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Junichiro Miake
- Department of Pharmacology, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Motokazu Tsuneto
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science, 86 Nishi-cho, Yonago, 683-8503, Japan
| | - Yasuaki Shirayoshi
- Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science, 86 Nishi-cho, Yonago, 683-8503, Japan
| | - Ryo Endo
- Department of Anesthesiology and Critical Care Medicine, Tottori University Faculty of Medicine, 86 Nishi-cho, Yonago, 683-8503, Japan
| | - Akihiro Otsuki
- Department of Anesthesiology and Critical Care Medicine, Tottori University Faculty of Medicine, 86 Nishi-cho, Yonago, 683-8503, Japan
| | - Futoshi Okada
- Division of Pathological Biochemistry, Tottori University Faculty of Medicine, Yonago, 683-8503, Japan
| | - Yoshimi Inagaki
- Department of Anesthesiology and Critical Care Medicine, Tottori University Faculty of Medicine, 86 Nishi-cho, Yonago, 683-8503, Japan
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11
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Ghani M, Nfonsam L, Pranckeviciene E, Daoud H, Potter R, Chisholm C, Harper PE, Schaffer A, Little L, Sinclair-Bourque E, McGowan-Jordan J, Smith A, Bronicki L, Jarinova O. Adopting High-Resolution Allele Frequencies Substantially Expedites Variant Interpretation in Genetic Diagnostic Laboratories. J Mol Diagn 2019; 21:602-611. [PMID: 31028938 DOI: 10.1016/j.jmoldx.2019.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 02/09/2019] [Accepted: 02/19/2019] [Indexed: 11/15/2022] Open
Abstract
A cohort of 1242 individuals tested in a clinical diagnostic laboratory was used to test whether the filtering allele frequencies (FAFs)-based framework, recently recommended for MHY7-associated cardiomyopathy, is extendable to 45 cardiomyopathy genes. Statistical analysis revealed a threshold of 0.00164% for the extreme outlier allele frequencies (AFs), based on the Genome Aggregation Database (exome fraction) total AFs of 138 unique pathogenic and likely pathogenic variants; 135 of them (97.8%) had AFs of <0.004%, the recommended threshold to apply moderate pathogenicity evidence for MYH7-associated cardiomyopathy. Of the 460 cases reported with only variant(s) of unknown clinical significance (VUCSs), 97 (21%) solely had VUCSs with FAFs >0.03%, frequencies above which were estimated herein as strong evidence against pathogenicity. Interestingly, 74.5% (172/231) of the unique VUCSs with FAFs >0.03% had Genome Aggregation Database maximum allele frequencies across all populations AFs >0.1%, deemed herein as stand-alone evidence against pathogenicity. Accordingly, using an FAF threshold of >0.1%, compared with AF >1%, led us to issue considerably more (25.9% versus 41.3%) negative patient reports. Also, 82.7% (N = 629) of the unique classified benign or likely benign variants with AFs <1% had FAFs >0.1%, reinforcing the use of this filtering strategy. Together, these data demonstrate that implementing FAF thresholds may considerably decrease the amount of variant interpretations and significantly reduce the cost of genetic testing for clinical genetic laboratories, without compromising the accuracy of genetic diagnostic services.
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Affiliation(s)
- Mahdi Ghani
- Department of Genetics, CHEO, Ottawa, Ontario, Canada.
| | | | - Erinija Pranckeviciene
- Department of Genetics, CHEO, Ottawa, Ontario, Canada; Department of Human and Medical Genetics, Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Hussein Daoud
- Department of Genetics, CHEO, Ottawa, Ontario, Canada
| | - Ryan Potter
- Department of Genetics, CHEO, Ottawa, Ontario, Canada
| | | | | | | | | | | | - Jean McGowan-Jordan
- Department of Genetics, CHEO, Ottawa, Ontario, Canada; Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Amanda Smith
- Department of Genetics, CHEO, Ottawa, Ontario, Canada; Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Lucas Bronicki
- Department of Genetics, CHEO, Ottawa, Ontario, Canada; Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Olga Jarinova
- Department of Genetics, CHEO, Ottawa, Ontario, Canada; Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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12
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Abstract
Cardiomyopathies are diseases of the myocardium, often genetically determined, associated with heterogeneous phenotypes and clinical manifestations. Despite significant progress in the understanding of these conditions, available treatments mostly target late complications, whereas approaches that promise to interfere with the primary mechanisms and natural history are just beginning to surface. The last decade has witnessed the establishment of large international cardiomyopathy registries, paralleled by advances in cardiac imaging and genetic testing, deeper understanding of the pathophysiology and growing involvement by the pharmaceutical industry. As a result, the number of molecular interventions under scrutiny is increasing sharply.
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13
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Smelter DF, de Lange WJ, Cai W, Ge Y, Ralphe JC. The HCM-linked W792R mutation in cardiac myosin-binding protein C reduces C6 FnIII domain stability. Am J Physiol Heart Circ Physiol 2018; 314:H1179-H1191. [PMID: 29451820 DOI: 10.1152/ajpheart.00686.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cardiac myosin-binding protein C (cMyBP-C) is a functional sarcomeric protein that regulates contractility in response to contractile demand, and many mutations in cMyBP-C lead to hypertrophic cardiomyopathy (HCM). To gain insight into the effects of disease-causing cMyBP-C missense mutations on contractile function, we expressed the pathogenic W792R mutation (substitution of a highly conserved tryptophan residue by an arginine residue at position 792) in mouse cardiomyocytes lacking endogenous cMyBP-C and studied the functional effects using three-dimensional engineered cardiac tissue constructs (mECTs). Based on complete conservation of tryptophan at this location in fibronectin type II (FnIII) domains, we hypothesized that the W792R mutation affects folding of the C6 FnIII domain, destabilizing the mutant protein. Adenoviral transduction of wild-type (WT) and W792R cDNA achieved equivalent mRNA transcript abundance, but not equivalent protein levels, with W792R compared with WT controls. mECTs expressing W792R demonstrated abnormal contractile kinetics compared with WT mECTs that were nearly identical to cMyBP-C-deficient mECTs. We studied whether common pathways of protein degradation were responsible for the rapid degradation of W792R cMyBP-C. Inhibition of both ubiquitin-proteasome and lysosomal degradation pathways failed to increase full-length mutant protein abundance to WT equivalence, suggesting rapid cytosolic degradation. Bacterial expression of WT and W792R protein fragments demonstrated decreased mutant stability with altered thermal denaturation and increased susceptibility to trypsin digestion. These data suggest that the W792R mutation destabilizes the C6 FnIII domain of cMyBP-C, resulting in decreased full-length protein expression. This study highlights the vulnerability of FnIII-like domains to mutations that alter domain stability and further indicates that missense mutations in cMyBP-C can cause disease through a mechanism of haploinsufficiency. NEW & NOTEWORTHY This study is one of the first to describe a disease mechanism for a missense mutation in cardiac myosin-binding protein C linked to hypertrophic cardiomyopathy. The mutation decreases stability of the fibronectin type III domain and results in substantially reduced mutant protein expression dissonant to transcript abundance.
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Affiliation(s)
- Dan F Smelter
- Department of Pediatrics, University of Wisconsin-Madison , Madison, Wisconsin
| | - Willem J de Lange
- Department of Pediatrics, University of Wisconsin-Madison , Madison, Wisconsin
| | - Wenxuan Cai
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison , Madison, Wisconsin.,Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison , Madison, Wisconsin
| | - Ying Ge
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison , Madison, Wisconsin.,Human Proteomics Program, University of Wisconsin-Madison , Madison, Wisconsin.,Department of Chemistry, School of Medicine and Public Health, University of Wisconsin-Madison , Madison, Wisconsin
| | - J Carter Ralphe
- Department of Pediatrics, University of Wisconsin-Madison , Madison, Wisconsin
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14
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Gilda JE, Gomes AV. Proteasome dysfunction in cardiomyopathies. J Physiol 2017; 595:4051-4071. [PMID: 28181243 DOI: 10.1113/jp273607] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/13/2017] [Indexed: 12/16/2022] Open
Abstract
The ubiquitin-proteasome system (UPS) plays a critical role in removing unwanted intracellular proteins and is involved in protein quality control, signalling and cell death. Because the heart is subject to continuous metabolic and mechanical stress, the proteasome plays a particularly important role in the heart, and proteasome dysfunction has been suggested as a causative factor in cardiac dysfunction. Proteasome impairment has been detected in cardiomyopathies, heart failure, myocardial ischaemia, and hypertrophy. Proteasome inhibition is also sufficient to cause cardiac dysfunction in healthy pigs, and patients using a proteasome inhibitor for cancer therapy have a higher incidence of heart failure. In this Topical Review we discuss the experimental data which suggest UPS dysfunction is a common feature of cardiomyopathies, with an emphasis on hypertrophic cardiomyopathy caused by sarcomeric mutations. We also propose potential mechanisms by which cardiomyopathy-causing mutations may lead to proteasome impairment, such as altered calcium handling and increased oxidative stress due to mitochondrial dysfunction.
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Affiliation(s)
- Jennifer E Gilda
- Department of Neurobiology, Physiology, and Behaviour, University of California, Davis, CA, 95616, USA
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology, and Behaviour, University of California, Davis, CA, 95616, USA.,Department of Physiology and Membrane Biology, University of California, Davis, CA, 95616, USA
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15
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Kondo T, Hisatome I, Yoshimura S, Mahati E, Notsu T, Li P, Iitsuka K, Kato M, Ogura K, Miake J, Aiba T, Shimizu W, Kurata Y, Sakata S, Nakasone N, Ninomiya H, Nakai A, Higaki K, Kawata Y, Shirayoshi Y, Yoshida A, Yamamoto K. Characterization of the novel mutant A78T-HERG from a long QT syndrome type 2 patient: Instability of the mutant protein and stabilization by heat shock factor 1. J Arrhythm 2016; 32:433-440. [PMID: 27761169 PMCID: PMC5063263 DOI: 10.1016/j.joa.2015.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 09/10/2015] [Accepted: 10/09/2015] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The human ether-a-go-go-related gene (HERG) encodes the α-subunit of rapidly activating delayed-rectifier potassium channels. Mutations in this gene cause long QT syndrome type 2 (LQT2). In most cases, mutations reduce the stability of the channel protein, which can be restored by heat shock (HS). METHODS We identified the novel mutant A78T-HERG in a patient with LQT2. The purpose of the current study was to characterize this mutant protein and test whether HS and heat shock factors (HSFs) could stabilize the mutant protein. A78T-HERG and wild-type HERG (WT-HERG) were expressed in HEK293 cells and analyzed by immunoblotting, immunoprecipitation, immunofluorescence, and whole-cell patch clamping. RESULTS When expressed in HEK293 cells, WT-HERG gave rise to immature and mature forms of the protein at 135 and 155 kDa, respectively. A78T-HERG gave rise only to the immature form, which was heavily ubiquitinated. The proteasome inhibitor MG132 increased the expression of immature A78T-HERG and increased both the immature and mature forms of WT-HERG. WT-HERG, but not A78T-HERG, was expressed on the plasma membrane. In whole-cell patch clamping experiments, depolarizing pulses evoked E4031-sensitive HERG channel currents in cells transfected with WT-HERG, but not in cells transfected with A78T-HERG. The A78V mutant, but not A78G mutant, remained in the immature form similarly to A78T. Maturation of the A78T-HERG protein was facilitated by HS, expression of HSF-1, or exposure to geranyl geranyl acetone. CONCLUSIONS A78T-HERG was characterized by protein instability and reduced expression on the plasma membrane. The stability of the mutant was partially restored by HSF-1, indicating that HSF-1 is a target for the treatment for LQT2 caused by the A78T mutation in HERG.
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Affiliation(s)
- Takehito Kondo
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University, Japan
| | - Ichiro Hisatome
- Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science, Japan
| | - Shouichi Yoshimura
- Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science, Japan
| | - Endang Mahati
- Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science, Japan
| | - Tomomi Notsu
- Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science, Japan
| | - Peili Li
- Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science, Japan
| | - Kazuhiko Iitsuka
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University, Japan
| | - Masaru Kato
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University, Japan
| | - Kazuyoshi Ogura
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University, Japan
| | - Junichiro Miake
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University, Japan
| | - Takeshi Aiba
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Wataru Shimizu
- Division of Cardiology and Regenerative Medicine, Nippon Medical School, Japan
| | - Yasutaka Kurata
- Department of Physiology II, Kanazawa Medical University, Japan
| | - Shinji Sakata
- Department of Pediatrics, Faculty of Medicine, Tottori University, Japan
| | - Naoe Nakasone
- Department of Biological Regulation, Faculty of Medicine, Tottori University, Japan
| | - Haruaki Ninomiya
- Department of Biological Regulation, Faculty of Medicine, Tottori University, Japan
| | - Akira Nakai
- Department of Biochemistry and Molecular Biology, Yamaguchi University School of Medicine, Japan
| | - Katsumi Higaki
- Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, Japan
| | - Yasushi Kawata
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Japan
| | - Yasuaki Shirayoshi
- Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science, Japan
| | - Akio Yoshida
- Division of Regenerative Medicine and Therapeutics, Tottori University Graduate School of Medical Science, Japan
| | - Kazuhiro Yamamoto
- Division of Cardiovascular Medicine, Department of Molecular Medicine and Therapeutics, Faculty of Medicine, Tottori University, Japan
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16
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Jaimes R, Walton RD, Pasdois P, Bernus O, Efimov IR, Kay MW. A technical review of optical mapping of intracellular calcium within myocardial tissue. Am J Physiol Heart Circ Physiol 2016; 310:H1388-401. [PMID: 27016580 DOI: 10.1152/ajpheart.00665.2015] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 03/21/2016] [Indexed: 12/18/2022]
Abstract
Optical mapping of Ca(2+)-sensitive fluorescence probes has become an extremely useful approach and adopted by many cardiovascular research laboratories to study a spectrum of myocardial physiology and disease conditions. Optical mapping data are often displayed as detailed pseudocolor images, providing unique insight for interpreting mechanisms of ectopic activity, action potential and Ca(2+) transient alternans, tachycardia, and fibrillation. Ca(2+)-sensitive fluorescent probes and optical mapping systems continue to evolve in the ongoing effort to improve therapies that ease the growing worldwide burden of cardiovascular disease. In this technical review we provide an updated overview of conventional approaches for optical mapping of Cai (2+) within intact myocardium. In doing so, a brief history of Cai (2+) probes is provided, and nonratiometric and ratiometric Ca(2+) probes are discussed, including probes for imaging sarcoplasmic reticulum Ca(2+) and probes compatible with potentiometric dyes for dual optical mapping. Typical measurements derived from optical Cai (2+) signals are explained, and the analytics used to compute them are presented. Last, recent studies using Cai (2+) optical mapping to study arrhythmias, heart failure, and metabolic perturbations are summarized.
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Affiliation(s)
- Rafael Jaimes
- Department of Biomedical Engineering, The George Washington University. Washington, District of Columbia
| | - Richard D Walton
- Université de Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France; Institut National de la Santé et de la Recherche Médicale, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France; and L'Institut de Rythmologie et Modélisation Cardiaque LIRYC, Université de Bordeaux, Bordeaux, France
| | - Philippe Pasdois
- Université de Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France; Institut National de la Santé et de la Recherche Médicale, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France; and L'Institut de Rythmologie et Modélisation Cardiaque LIRYC, Université de Bordeaux, Bordeaux, France
| | - Olivier Bernus
- Université de Bordeaux, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France; Institut National de la Santé et de la Recherche Médicale, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France; and L'Institut de Rythmologie et Modélisation Cardiaque LIRYC, Université de Bordeaux, Bordeaux, France
| | - Igor R Efimov
- Department of Biomedical Engineering, The George Washington University. Washington, District of Columbia; L'Institut de Rythmologie et Modélisation Cardiaque LIRYC, Université de Bordeaux, Bordeaux, France
| | - Matthew W Kay
- Department of Biomedical Engineering, The George Washington University. Washington, District of Columbia;
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17
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Kumar KR, Mandleywala SN, Link MS. Atrial and ventricular arrhythmias in hypertrophic cardiomyopathy. Card Electrophysiol Clin 2015; 7:173-86. [PMID: 26002384 DOI: 10.1016/j.ccep.2015.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease caused by mutations in genes coding for cardiac sarcomeres. HCM is the most common inherited heart disease, with a prevalence of 0.2%. There are multiple genetic variants that cause pleomorphic clinical attributes and disease characterized by myocardial disarray and myocardial hypertrophy. Patients are at an increased risk of atrial and ventricular arrhythmias. Management of these arrhythmias is complex. Atrial fibrillation is associated with increased mortality and thromboembolism. Ventricular arrhythmias are life threatening and best treated with an implantable defibrillator.
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Affiliation(s)
- Kartik R Kumar
- Department of Cardiology, Tufts Medical Center, 800 Washington Street, Boston, MA 02111, USA
| | - Swati N Mandleywala
- Department of Cardiology, Tufts Medical Center, 800 Washington Street, Boston, MA 02111, USA
| | - Mark S Link
- Department of Cardiology, Tufts Medical Center, 800 Washington Street, Boston, MA 02111, USA.
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18
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Ishikawa T, Jou CJ, Nogami A, Kowase S, Arrington CB, Barnett SM, Harrell DT, Arimura T, Tsuji Y, Kimura A, Makita N. Novel mutation in the α-myosin heavy chain gene is associated with sick sinus syndrome. Circ Arrhythm Electrophysiol 2015; 8:400-8. [PMID: 25717017 DOI: 10.1161/circep.114.002534] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/11/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Recent genome-wide association studies have demonstrated an association between MYH6, the gene encoding α-myosin heavy chain (α-MHC), and sinus node function in the general population. Moreover, a rare MYH6 variant, R721W, predisposing susceptibility to sick sinus syndrome has been identified. However, the existence of disease-causing MYH6 mutations for familial sick sinus syndrome and their underlying mechanisms remain unknown. METHODS AND RESULTS We screened 9 genotype-negative probands with sick sinus syndrome families for mutations in MYH6 and identified an in-frame 3-bp deletion predicted to delete one residue (delE933) at the highly conserved coiled-coil structure within the binding motif to myosin-binding protein C in one patient. Co-immunoprecipitation analysis revealed enhanced binding of delE933 α-MHC to myosin-binding protein C. Irregular fluorescent speckles retained in the cytoplasm with substantially disrupted sarcomere striation were observed in neonatal rat cardiomyocytes transfected with α-MHC mutants carrying delE933 or R721W. In addition to the sarcomere impairments, delE933 α-MHC exhibited electrophysiological abnormalities both in vitro and in vivo. The atrial cardiomyocyte cell line HL-1 stably expressing delE933 α-MHC showed a significantly slower conduction velocity on multielectrode array than those of wild-type α-MHC or control plasmid transfected cells. Furthermore, targeted morpholino knockdown of MYH6 in zebrafish significantly reduced the heart rate, which was rescued by coexpressed wild-type human α-MHC but not by delE933 α-MHC. CONCLUSIONS The novel MYH6 mutation delE933 causes both structural damage of the sarcomere and functional impairments on atrial action propagation. This report reinforces the relevance of MYH6 for sinus node function and identifies a novel pathophysiology underlying familial sick sinus syndrome.
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Affiliation(s)
- Taisuke Ishikawa
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.)
| | - Chuanchau J Jou
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.)
| | - Akihiko Nogami
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.)
| | - Shinya Kowase
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.)
| | - Cammon B Arrington
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.)
| | - Spencer M Barnett
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.)
| | - Daniel T Harrell
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.)
| | - Takuro Arimura
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.)
| | - Yukiomi Tsuji
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.)
| | - Akinori Kimura
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.).
| | - Naomasa Makita
- From the Department of Molecular Physiology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki (T.I., D.T.H., Y.T., N.M.); Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan (T.I., T.A., A.K.); Division of Pediatric Cardiology, University of Utah, Salt Lake City (C.J.J., C.B.A., S.M.B.); Cardiovascular Division, University of Tsukuba, Tsukuba (A.N.); Department of Heart Rhythm Management, Yokohama Rosai Hospital, Yokohama (A.N., S.K.); and Department of Veterinary Medicine, Kagoshima University, Kagoshima, Japan (T.A.).
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Saenen J, Van Craenenbroeck E, Proost D, Marchau F, Van Laer L, Vrints C, Loeys B. Genetics of sudden cardiac death in the young. Clin Genet 2014; 88:101-13. [DOI: 10.1111/cge.12519] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 10/06/2014] [Accepted: 10/06/2014] [Indexed: 11/29/2022]
Affiliation(s)
- J.B. Saenen
- Department of Cardiology; Antwerp University Hospital/University of Antwerp; Antwerp Belgium
| | - E.M. Van Craenenbroeck
- Department of Cardiology; Antwerp University Hospital/University of Antwerp; Antwerp Belgium
| | - D. Proost
- Center for Medical Genetics; Antwerp University Hospital/University of Antwerp; Antwerp Belgium
| | - F. Marchau
- Department of Pediatric Cardiology; Antwerp University Hospital/University of Antwerp; Antwerp Belgium
| | - L. Van Laer
- Center for Medical Genetics; Antwerp University Hospital/University of Antwerp; Antwerp Belgium
| | - C.J. Vrints
- Department of Cardiology; Antwerp University Hospital/University of Antwerp; Antwerp Belgium
| | - B.L. Loeys
- Center for Medical Genetics; Antwerp University Hospital/University of Antwerp; Antwerp Belgium
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20
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Puglisi JL, Goldspink PH, Gomes AV, Utter MS, Bers DM, Solaro RJ. Influence of a constitutive increase in myofilament Ca(2+)-sensitivity on Ca(2+)-fluxes and contraction of mouse heart ventricular myocytes. Arch Biochem Biophys 2014; 552-553:50-9. [PMID: 24480308 PMCID: PMC4043955 DOI: 10.1016/j.abb.2014.01.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/02/2014] [Accepted: 01/18/2014] [Indexed: 11/25/2022]
Abstract
Chronic increases in myofilament Ca(2+)-sensitivity in the heart are known to alter gene expression potentially modifying Ca(2+)-homeostasis and inducing arrhythmias. We tested age-dependent effects of a chronic increase in myofilament Ca(2+)-sensitivity on induction of altered alter gene expression and activity of Ca(2+) transport systems in cardiac myocytes. Our approach was to determine the relative contributions of the major mechanisms responsible for restoring Ca(2+) to basal levels in field stimulated ventricular myocytes. Comparisons were made from ventricular myocytes isolated from non-transgenic (NTG) controls and transgenic mice expressing the fetal, slow skeletal troponin I (TG-ssTnI) in place of cardiac TnI (cTnI). Replacement of cTnI by ssTnI induces an increase in myofilament Ca(2+)-sensitivity. Comparisons included myocytes from relatively young (5-7months) and older mice (11-13months). Employing application of caffeine in normal Tyrode and in 0Na(+) 0Ca(2+) solution, we were able to dissect the contribution of the sarcoplasmic reticulum Ca(2+) pump (SR Ca(2+)-ATPase), the Na(+)/Ca(2+) exchanger (NCX), and "slow mechanisms" representing the activity of the sarcolemmal Ca(2+) pump and the mitochondrial Ca(2+) uniporter. The relative contribution of the SR Ca(2+)-ATPase to restoration of basal Ca(2+) levels in younger TG-ssTnI myocytes was lower than in NTG (81.12±2.8% vs 92.70±1.02%), but the same in the older myocytes. Younger and older NTG myocytes demonstrated similar contributions from the SR Ca(2+)-ATPase and NCX to restoration of basal Ca(2+). However, the slow mechanisms for Ca(2+) removal were increased in the older NTG (3.4±0.3%) vs the younger NTG myocytes (1.4±0.1%). Compared to NTG, younger TG-ssTnI myocytes demonstrated a significantly bigger contribution of the NCX (16±2.7% in TG vs 6.9±0.9% in NTG) and slow mechanisms (3.3±0.4% in TG vs 1.4±0.1% in NTG). In older TG-ssTnI myocytes the contributions were not significantly different from NTG (NCX: 4.9±0.6% in TG vs 5.5±0.7% in NTG; slow mechanisms: 2.5±0.3% in TG vs 3.4±0.3% in NTG). Our data indicate that constitutive increases in myofilament Ca(2+)-sensitivity alter the relative significance of the NCX transport system involved in Ca(2+)-homeostasis only in a younger group of mice. This modification may be of significance in early changes in altered gene expression and electrical stability hearts with increased myofilament Ca-sensitivity.
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Affiliation(s)
- Jose L Puglisi
- Department of Pharmacology, University of California Davis, Davis, CA 95616, United States
| | - Paul H Goldspink
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology, and Behavior, University of California Davis, Davis, CA 95616, United States
| | - Megan S Utter
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Donald M Bers
- Department of Pharmacology, University of California Davis, Davis, CA 95616, United States
| | - R John Solaro
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, United States.
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21
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Rare variants in genes encoding MuRF1 and MuRF2 are modifiers of hypertrophic cardiomyopathy. Int J Mol Sci 2014; 15:9302-13. [PMID: 24865491 PMCID: PMC4100095 DOI: 10.3390/ijms15069302] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 04/23/2014] [Accepted: 04/30/2014] [Indexed: 11/24/2022] Open
Abstract
Modifier genes contribute to the diverse clinical manifestations of hypertrophic cardiomyopathy (HCM), but are still largely unknown. Muscle ring finger (MuRF) proteins are a class of muscle-specific ubiquitin E3-ligases that appear to modulate cardiac mass and function by regulating the ubiquitin-proteasome system. In this study we screened all the three members of the MuRF family, MuRF1, MuRF2 and MuRF3, in 594 unrelated HCM patients and 307 healthy controls by targeted resequencing. Identified rare variants were confirmed by capillary Sanger sequencing. The prevalence of rare variants in both MuRF1 and MuRF2 in HCM patients was higher than that in control subjects (MuRF1 13/594 (2.2%) vs. 1/307 (0.3%), p = 0.04; MuRF2 22/594 (3.7%) vs. 2/307 (0.7%); p = 0.007). Patients with rare variants in MuRF1 or MuRF2 were younger (p = 0.04) and had greater maximum left ventricular wall thickness (p = 0.006) than those without such variants. Mutations in genes encoding sarcomere proteins were present in 19 (55.9%) of the 34 HCM patients with rare variants in MuRF1 and MuRF2. These data strongly supported that rare variants in MuRF1 and MuRF2 are associated with higher penetrance and more severe clinical manifestations of HCM. The findings suggest that dysregulation of the ubiquitin-proteasome system contributes to the pathogenesis of HCM.
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22
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Schlossarek S, Frey N, Carrier L. Ubiquitin-proteasome system and hereditary cardiomyopathies. J Mol Cell Cardiol 2013; 71:25-31. [PMID: 24380728 DOI: 10.1016/j.yjmcc.2013.12.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 11/13/2013] [Accepted: 12/17/2013] [Indexed: 12/14/2022]
Abstract
Adequate protein turnover is essential for cardiac homeostasis. Different protein quality controls are involved in the maintenance of protein homeostasis, including molecular chaperones and co-chaperones, the autophagy-lysosomal pathway, and the ubiquitin-proteasome system (UPS). In the last decade, a series of evidence has underlined a major function of the UPS in cardiac physiology and disease. Particularly, recent studies have shown that dysfunctional proteasomal function leads to cardiac disorders. Hypertrophic and dilated cardiomyopathies are the two most prevalent inherited cardiomyopathies. Both are primarily transmitted as an autosomal-dominant trait and mainly caused by mutations in genes encoding components of the cardiac sarcomere, including a relevant striated muscle-specific E3 ubiquitin ligase. A growing body of evidence indicates impairment of the UPS in inherited cardiomyopathies as determined by measurement of the level of ubiquitinated proteins, the activities of the proteasome and/or the use of fluorescent UPS reporter substrates. The present review will propose mechanisms of UPS impairment in inherited cardiomyopathies, summarize the potential consequences of UPS impairment, including activation of the unfolded protein response, and underline some therapeutic options available to restore proteasome function and therefore cardiac homeostasis and function. This article is part of a Special Issue entitled "Protein Quality Control, the Ubiquitin Proteasome System, and Autophagy".
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Affiliation(s)
- Saskia Schlossarek
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Norbert Frey
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany; Department of Cardiology and Angiology, University of Kiel, Kiel, Germany
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany; Inserm, U974, Paris F-75013, France; Université Pierre et Marie Curie- Paris 6, UM 76, CNRS, UMR 7215, Institut de Myologie, IFR14, Paris F-75013, France.
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23
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The mitochondrial Na+-Ca2+ exchanger, NCLX, regulates automaticity of HL-1 cardiomyocytes. Sci Rep 2013; 3:2766. [PMID: 24067497 PMCID: PMC3783885 DOI: 10.1038/srep02766] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 09/05/2013] [Indexed: 01/10/2023] Open
Abstract
Mitochondrial Ca2+ is known to change dynamically, regulating mitochondrial as well as cellular functions such as energy metabolism and apoptosis. The NCLX gene encodes the mitochondrial Na+-Ca2+ exchanger (NCXmit), a Ca2+ extrusion system in mitochondria. Here we report that the NCLX regulates automaticity of the HL-1 cardiomyocytes. NCLX knockdown using siRNA resulted in the marked prolongation of the cycle length of spontaneous Ca2+ oscillation and action potential generation. The upstrokes of action potential and Ca2+ transient were markedly slower, and sarcoplasmic reticulum (SR) Ca2+ handling were compromised in the NCLX knockdown cells. Analyses using a mathematical model of HL-1 cardiomyocytes demonstrated that blocking NCXmit reduced the SR Ca2+ content to slow spontaneous SR Ca2+ leak, which is a trigger of automaticity. We propose that NCLX is a novel molecule to regulate automaticity of cardiomyocytes via modulating SR Ca2+ handling.
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24
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Costa MW, Guo G, Wolstein O, Vale M, Castro ML, Wang L, Otway R, Riek P, Cochrane N, Furtado M, Semsarian C, Weintraub RG, Yeoh T, Hayward C, Keogh A, Macdonald P, Feneley M, Graham RM, Seidman JG, Seidman CE, Rosenthal N, Fatkin D, Harvey RP. Functional characterization of a novel mutation in NKX2-5 associated with congenital heart disease and adult-onset cardiomyopathy. ACTA ACUST UNITED AC 2013; 6:238-47. [PMID: 23661673 DOI: 10.1161/circgenetics.113.000057] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND The transcription factor NKX2-5 is crucial for heart development, and mutations in this gene have been implicated in diverse congenital heart diseases and conduction defects in mouse models and humans. Whether NKX2-5 mutations have a role in adult-onset heart disease is unknown. METHODS AND RESULTS Mutation screening was performed in 220 probands with adult-onset dilated cardiomyopathy. Six NKX2-5 coding sequence variants were identified, including 3 nonsynonymous variants. A novel heterozygous mutation, I184M, located within the NKX2-5 homeodomain, was identified in 1 family. A subset of family members had congenital heart disease, but there was an unexpectedly high prevalence of dilated cardiomyopathy. Functional analysis of I184M in vitro demonstrated a striking increase in protein expression when transfected into COS-7 cells or HL-1 cardiomyocytes because of reduced degradation by the Ubiquitin-proteasome system. In functional assays, DNA-binding activity of I184M was reduced, resulting in impaired activation of target genes despite increased expression levels of mutant protein. CONCLUSIONS Certain NKX2-5 homeodomain mutations show abnormal protein degradation via the Ubiquitin-proteasome system and partially impaired transcriptional activity. We propose that this class of mutation can impair heart development and mature heart function and contribute to NKX2-5-related cardiomyopathies with graded severity.
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Affiliation(s)
- Mauro W Costa
- Developmental and Stem Cell Biology Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.
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25
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Abstract
Maintenance of protein quality control is a critical function of the ubiquitin proteasome system (UPS). Evidence is rapidly mounting to link proteasome dysfunction with a multitude of cardiac diseases, including ischemia, reperfusion, atherosclerosis, hypertrophy, heart failure, and cardiomyopathies. Recent studies have demonstrated a remarkable level of complexity in the regulation of the UPS in the heart and suggest that our understanding of how UPS dysfunction might contribute to the pathophysiology of such a wide range of cardiac afflictions is still very limited. Whereas experimental systems, including animal models, are invaluable for exploring mechanisms and establishing pathogenicity of UPS dysfunction in cardiac disease, studies using human heart tissue provide a vital adjunct for establishing clinical relevance of experimental findings and promoting new hypotheses. Accordingly, this review will focus on UPS dysfunction in human dilated and hypertrophic cardiomyopathies and highlight areas rich for further study in this expanding field.
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Affiliation(s)
- Sharlene M Day
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI, USA.
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26
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Preventive and therapeutic effects of MG132 by activating Nrf2-ARE signaling pathway on oxidative stress-induced cardiovascular and renal injury. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:306073. [PMID: 23533688 PMCID: PMC3606804 DOI: 10.1155/2013/306073] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 02/14/2013] [Indexed: 12/25/2022]
Abstract
So far, cardiovascular and renal diseases have brought us not only huge economic burden but also serious society problems. Since effective therapeutic strategies are still limited, to find new methods for the prevention or therapy of these diseases is important. Oxidative stress has been found to play a critical role in the initiation and progression of cardiovascular and renal diseases. In addition, activation of nuclear-factor-E2-related-factor-2- (Nrf2-) antioxidant-responsive element (ARE) signaling pathway protects cells and tissues from oxidative damage. As a proteasomal inhibitor, MG132 was reported to activate Nrf2 expression and function, which was accompanied with significant preventive and/or therapeutic effect on cardiovascular and renal diseases under most conditions; therefore, MG132 seems to be a potentially effective drug to be used in the prevention of oxidative damage. In this paper, we will summarize the information available regarding the effect of MG132 on oxidative stress-induced cardiovascular and renal damage, especially through Nrf2-ARE signaling pathway.
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27
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O'Mahony C, Elliott P, McKenna W. Sudden cardiac death in hypertrophic cardiomyopathy. Circ Arrhythm Electrophysiol 2012; 6:443-51. [PMID: 23022709 DOI: 10.1161/circep.111.962043] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Constantinos O'Mahony
- The Inherited Cardiac Diseases Unit, The Heart Hospital/University College London, London, United Kingdom
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28
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Sadayappan S, de Tombe PP. Cardiac myosin binding protein-C: redefining its structure and function. Biophys Rev 2012; 4:93-106. [PMID: 22707987 PMCID: PMC3374655 DOI: 10.1007/s12551-012-0067-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 01/13/2012] [Indexed: 01/10/2023] Open
Abstract
Mutations of cardiac myosin binding protein-C (cMyBP-C) are inherited by an estimated 60 million people worldwide, and the protein is the target of several kinases. Recent evidence further suggests that cMyBP-C mutations alter Ca(2+) transients, leading to electrophysiological dysfunction. Thus, while the importance of studying this cardiac sarcomere protein is clear, preliminary data in the literature have raised many questions. Therefore, in this article, we propose to review the structure and function of cMyBP-C with particular respect to the role(s) in cardiac contractility and whether its release into the circulatory system is a potential biomarker of myocardial infarction. We also discuss future directions and experimental designs that may lead to expanding the role(s) of cMyBP-C in the heart. In conclusion, we suggest that cMyBP-C is a regulatory protein that could offer a broad clinical utility in maintaining normal cardiac function.
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Affiliation(s)
- Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 South First Ave., Maywood, IL 60153 USA
| | - Pieter P. de Tombe
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, 2160 South First Ave., Maywood, IL 60153 USA
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29
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Pfuhl M, Gautel M. Structure, interactions and function of the N-terminus of cardiac myosin binding protein C (MyBP-C): who does what, with what, and to whom? J Muscle Res Cell Motil 2012; 33:83-94. [PMID: 22527637 DOI: 10.1007/s10974-012-9291-z] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 03/24/2012] [Indexed: 02/04/2023]
Abstract
The thick filament protein myosin-binding protein-C shows a highly modular architecture, with the C-terminal region responsible for tethering to the myosin and titin backbone of the thick filament. The N-terminal region shows the most significant differences between cardiac and skeletal muscle isogenes: an entire Ig-domain (C0) is added, together with highly regulated phosphorylation sites between Ig domains C1 and C2. These structural and functional differences at the N-terminus reflect important functions in cardiac muscle regulation in health and disease. Alternative interactions of this part of MyBP-C with the head-tail (S1-S2) junction of myosin or to actin filaments have been proposed, but with conflicting experimental evidence. The regulation of myosin or actin interaction by phosphorylation of the cardiac MyBP-C N-terminus may play an additional role in length-dependent contraction regulation. We discuss here the evidence for these proposed interactions, considering the required properties of MyBP-C, the way in which they may be regulated in muscle contraction and the way they might be related to heart disease. We also attempt to shed some light on experimental pitfalls and future strategies.
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Affiliation(s)
- Mark Pfuhl
- Randall Division for Cell and Molecular Biophysics and Cardiovascular Division, King's College London BHF Centre of Research Excellence, London, UK.
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